|
Concentration producing 50% of the maximal increase in the force of contraction in isolated guinea pig left atrium
|
Cavia porcellus
|
380.0
nM
|
|
Journal : J. Med. Chem.
Title : 17beta-O-Aminoalkyloximes of 5beta-androstane-3beta,14beta-diol with digitalis-like activity: synthesis, cardiotonic activity, structure-activity relationships, and molecular modeling of the Na(+),K(+)-ATPase receptor.
Year : 2000
Volume : 43
Issue : 12
First Page : 2332
Last Page : 2349
Authors : Cerri A, Almirante N, Barassi P, Benicchio A, Fedrizzi G, Ferrari P, Micheletti R, Quadri L, Ragg E, Rossi R, Santagostino M, Schiavone A, Serra F, Zappavigna MP, Melloni P.
Abstract : A series of digitalis-like compounds with a 17-aminoalkoxyiminoalkyl or -alkenyl substituent was synthesized and evaluated for inhibition of Na(+),K(+)-ATPase and for inotropic activity. The highest inhibition was found with compounds having the substituent in configuration 17beta and the amino group at a distance of 6 or 7 bonds from C(17) of the digitoxigenin skeleton. The presence of the oxime function strengthens the interaction with the receptor, more if alpha,beta-unsaturated, thus mimicking the electronic situation of the unsaturated lactone in natural digitalis compounds. The most active compounds showed Na(+),K(+)-ATPase inhibitory potencies (IC(50)) 17-25 times higher than the standards digitoxigenin and digoxin and 3-11 times higher inotropic potencies (EC(50)) in isolated guinea pig left atria. These features are supported by a molecular model suggesting the possible interactions of the groups described above with particular amino acid residues in the H1-H2 domains of Na(+),K(+)-ATPase. Some interactions are the classical ones already described in the literature; a new, very strong interaction of the basic group with the Cys138 was found and adds new possibilities to design compounds interacting with this region of the receptor. The most interesting compounds were also studied in vivo in the anesthetized guinea pig for evaluating their inotropic effect versus the lethal dose. Compounds 9 and 12 showed a slightly higher safety ratio than digoxin and deserve further evaluation.
|
In vitro inotropic activity was determined by the affects of contractile force on guinea pig left atrium.
|
Cavia porcellus
|
400.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis, cardiotonic activity, and structure-activity relationships of 17 beta-guanylhydrazone derivatives of 5 beta-androstane-3 beta, 14 beta-diol acting on the Na+,K(+)-ATPase receptor.
Year : 1997
Volume : 40
Issue : 21
First Page : 3484
Last Page : 3488
Authors : Cerri A, Serra F, Ferrari P, Folpini E, Padoani G, Melloni P.
Abstract : A series of digitalis-like compounds, with the lactone ring shifted from the original position through a spacer or replaced by a series of guanylhydrazone substituent-bearing chains, was synthesized and evaluated for inhibition of Na+,K(+)-ATPase and for inotropic activity. The highest Na+,K(+)-ATPase inhibition (IC50) and inotropic activity (EC50) were reached with the vinylogous guanylhydrazone 5 where a cardenolide-like polarized alpha,beta-unsaturated system and a basic guanidino group were both present at the 17 beta-position; for this compound IC50 and EC50 values were comparable to or higher than those of Thomas' parent guanylhydrazone 1, digitoxigenin, and digoxin. A substantial improvement of the desired positive inotropic activity versus the toxic arrhythmogenic concentration was not reached within this series; only a slightly better therapeutic index can be envisaged for compounds 5 and 4, even though, for the latter, to the detriment of potency, presumably because of a weaker interaction with the receptor, due to the lack of a cardenolide-like polarized system.
|
Kinetic parameter against Monoclonal antibody mAB-1B3
|
None
|
3.1
nM
|
|
Journal : J. Med. Chem.
Title : Three-dimensional quantitative structure-activity relationship analysis of ligand binding to human sequence antidigoxin monoclonal antibodies using comparative molecular field analysis.
Year : 2002
Volume : 45
Issue : 15
First Page : 3257
Last Page : 3270
Authors : Farr CD, Tabet MR, Ball WJ, Fishwild DM, Wang X, Nair AC, Welsh WJ.
Abstract : The present study indicates that the newly generated human sequence antidigoxin monoclonal antibody (mAb), 1B3, binds digoxin with a different fine specificity binding than our previously obtained human sequence monoclonal antibodies (mAbs) (Ball, W. J.; et al. J. Immunol. 1999, 163, 2291-2298). Uniquely, 1B3 has a higher affinity for digitoxin than digoxin, the immunizing hapten, and a strong requirement for at least one sugar residue linked to the aglycone (-genin). By means of comparative molecular field analysis (CoMFA), the results of competition binding studies for 56 cardiotonic and hormonal steroids were employed to develop three-dimensional quantitative structure-activity relationship (3D-QSAR) models for ligand binding to 1B3 and to three additional human sequence mAbs, as well as the murine antidigoxin mAb 40-50 (Mudgett-Hunter, M.; et al. Mol. Immunol. 1985, 22, 447-488). All five 3D-QSAR models yielded cross-validated q(2) values greater than 0.5, which indicates that they have significant predictive ability. The CoMFA StDevCoeff contour plots, as well as the competition results, indicate that 1B3 binds ligands in a manner distinct from the other four mAbs. The CoMFA contour plots for 40-50 were also compared with the known X-ray crystallographic structure of the 40-50-ouabain complex (Jeffrey, P. D.; et al. J. Mol. Biol. 1995, 248, 344-360) in order to identify correlations between residues in the mAb binding site and specific contour plot regions. These 3D-QSAR models and their respective contour plots should be useful tools to further understand the molecular nature of antibody-antigen interactions and to aid in the redesign or enhancement of therapeutic antibodies.
|
Binding affinity against Monoclonal antibody mAB-1B3 using [3H]digoxin as radioligand
|
None
|
1.2
nM
|
|
Journal : J. Med. Chem.
Title : Three-dimensional quantitative structure-activity relationship analysis of ligand binding to human sequence antidigoxin monoclonal antibodies using comparative molecular field analysis.
Year : 2002
Volume : 45
Issue : 15
First Page : 3257
Last Page : 3270
Authors : Farr CD, Tabet MR, Ball WJ, Fishwild DM, Wang X, Nair AC, Welsh WJ.
Abstract : The present study indicates that the newly generated human sequence antidigoxin monoclonal antibody (mAb), 1B3, binds digoxin with a different fine specificity binding than our previously obtained human sequence monoclonal antibodies (mAbs) (Ball, W. J.; et al. J. Immunol. 1999, 163, 2291-2298). Uniquely, 1B3 has a higher affinity for digitoxin than digoxin, the immunizing hapten, and a strong requirement for at least one sugar residue linked to the aglycone (-genin). By means of comparative molecular field analysis (CoMFA), the results of competition binding studies for 56 cardiotonic and hormonal steroids were employed to develop three-dimensional quantitative structure-activity relationship (3D-QSAR) models for ligand binding to 1B3 and to three additional human sequence mAbs, as well as the murine antidigoxin mAb 40-50 (Mudgett-Hunter, M.; et al. Mol. Immunol. 1985, 22, 447-488). All five 3D-QSAR models yielded cross-validated q(2) values greater than 0.5, which indicates that they have significant predictive ability. The CoMFA StDevCoeff contour plots, as well as the competition results, indicate that 1B3 binds ligands in a manner distinct from the other four mAbs. The CoMFA contour plots for 40-50 were also compared with the known X-ray crystallographic structure of the 40-50-ouabain complex (Jeffrey, P. D.; et al. J. Mol. Biol. 1995, 248, 344-360) in order to identify correlations between residues in the mAb binding site and specific contour plot regions. These 3D-QSAR models and their respective contour plots should be useful tools to further understand the molecular nature of antibody-antigen interactions and to aid in the redesign or enhancement of therapeutic antibodies.
|
Binding affinity against Monoclonal antibody mAB-1B3 using [3H]digitoxin as radioligand
|
None
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Three-dimensional quantitative structure-activity relationship analysis of ligand binding to human sequence antidigoxin monoclonal antibodies using comparative molecular field analysis.
Year : 2002
Volume : 45
Issue : 15
First Page : 3257
Last Page : 3270
Authors : Farr CD, Tabet MR, Ball WJ, Fishwild DM, Wang X, Nair AC, Welsh WJ.
Abstract : The present study indicates that the newly generated human sequence antidigoxin monoclonal antibody (mAb), 1B3, binds digoxin with a different fine specificity binding than our previously obtained human sequence monoclonal antibodies (mAbs) (Ball, W. J.; et al. J. Immunol. 1999, 163, 2291-2298). Uniquely, 1B3 has a higher affinity for digitoxin than digoxin, the immunizing hapten, and a strong requirement for at least one sugar residue linked to the aglycone (-genin). By means of comparative molecular field analysis (CoMFA), the results of competition binding studies for 56 cardiotonic and hormonal steroids were employed to develop three-dimensional quantitative structure-activity relationship (3D-QSAR) models for ligand binding to 1B3 and to three additional human sequence mAbs, as well as the murine antidigoxin mAb 40-50 (Mudgett-Hunter, M.; et al. Mol. Immunol. 1985, 22, 447-488). All five 3D-QSAR models yielded cross-validated q(2) values greater than 0.5, which indicates that they have significant predictive ability. The CoMFA StDevCoeff contour plots, as well as the competition results, indicate that 1B3 binds ligands in a manner distinct from the other four mAbs. The CoMFA contour plots for 40-50 were also compared with the known X-ray crystallographic structure of the 40-50-ouabain complex (Jeffrey, P. D.; et al. J. Mol. Biol. 1995, 248, 344-360) in order to identify correlations between residues in the mAb binding site and specific contour plot regions. These 3D-QSAR models and their respective contour plots should be useful tools to further understand the molecular nature of antibody-antigen interactions and to aid in the redesign or enhancement of therapeutic antibodies.
|
In vitro inhibitory concentration against dog kidney Na+,K+-ATPase
|
Canis lupus familiaris
|
500.0
nM
|
|
Journal : J. Med. Chem.
Title : 17beta-O-Aminoalkyloximes of 5beta-androstane-3beta,14beta-diol with digitalis-like activity: synthesis, cardiotonic activity, structure-activity relationships, and molecular modeling of the Na(+),K(+)-ATPase receptor.
Year : 2000
Volume : 43
Issue : 12
First Page : 2332
Last Page : 2349
Authors : Cerri A, Almirante N, Barassi P, Benicchio A, Fedrizzi G, Ferrari P, Micheletti R, Quadri L, Ragg E, Rossi R, Santagostino M, Schiavone A, Serra F, Zappavigna MP, Melloni P.
Abstract : A series of digitalis-like compounds with a 17-aminoalkoxyiminoalkyl or -alkenyl substituent was synthesized and evaluated for inhibition of Na(+),K(+)-ATPase and for inotropic activity. The highest inhibition was found with compounds having the substituent in configuration 17beta and the amino group at a distance of 6 or 7 bonds from C(17) of the digitoxigenin skeleton. The presence of the oxime function strengthens the interaction with the receptor, more if alpha,beta-unsaturated, thus mimicking the electronic situation of the unsaturated lactone in natural digitalis compounds. The most active compounds showed Na(+),K(+)-ATPase inhibitory potencies (IC(50)) 17-25 times higher than the standards digitoxigenin and digoxin and 3-11 times higher inotropic potencies (EC(50)) in isolated guinea pig left atria. These features are supported by a molecular model suggesting the possible interactions of the groups described above with particular amino acid residues in the H1-H2 domains of Na(+),K(+)-ATPase. Some interactions are the classical ones already described in the literature; a new, very strong interaction of the basic group with the Cys138 was found and adds new possibilities to design compounds interacting with this region of the receptor. The most interesting compounds were also studied in vivo in the anesthetized guinea pig for evaluating their inotropic effect versus the lethal dose. Compounds 9 and 12 showed a slightly higher safety ratio than digoxin and deserve further evaluation.
|
Inhibition of Na+/K+ ATPase from dog kidney
|
Canis lupus familiaris
|
500.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis, cardiotonic activity, and structure-activity relationships of 17 beta-guanylhydrazone derivatives of 5 beta-androstane-3 beta, 14 beta-diol acting on the Na+,K(+)-ATPase receptor.
Year : 1997
Volume : 40
Issue : 21
First Page : 3484
Last Page : 3488
Authors : Cerri A, Serra F, Ferrari P, Folpini E, Padoani G, Melloni P.
Abstract : A series of digitalis-like compounds, with the lactone ring shifted from the original position through a spacer or replaced by a series of guanylhydrazone substituent-bearing chains, was synthesized and evaluated for inhibition of Na+,K(+)-ATPase and for inotropic activity. The highest Na+,K(+)-ATPase inhibition (IC50) and inotropic activity (EC50) were reached with the vinylogous guanylhydrazone 5 where a cardenolide-like polarized alpha,beta-unsaturated system and a basic guanidino group were both present at the 17 beta-position; for this compound IC50 and EC50 values were comparable to or higher than those of Thomas' parent guanylhydrazone 1, digitoxigenin, and digoxin. A substantial improvement of the desired positive inotropic activity versus the toxic arrhythmogenic concentration was not reached within this series; only a slightly better therapeutic index can be envisaged for compounds 5 and 4, even though, for the latter, to the detriment of potency, presumably because of a weaker interaction with the receptor, due to the lack of a cardenolide-like polarized system.
|
Inhibitory activity against Na+/K+ ATPase was determined
|
Canis lupus familiaris
|
400.0
nM
|
|
Journal : J. Med. Chem.
Title : Structure-based design and synthesis of novel potent Na+,K+ -ATPase inhibitors derived from a 5alpha,14alpha-androstane scaffold as positive inotropic compounds.
Year : 2003
Volume : 46
Issue : 17
First Page : 3644
Last Page : 3654
Authors : De Munari S, Cerri A, Gobbini M, Almirante N, Banfi L, Carzana G, Ferrari P, Marazzi G, Micheletti R, Schiavone A, Sputore S, Torri M, Zappavigna MP, Melloni P.
Abstract : The design, synthesis, and biological properties of novel inhibitors of the Na(+),K(+)-ATPase as potential positive inotropic compounds are reported. Following our model of superposition between cassaine and digitoxigenin, digitalis-like activity has been elicited from a non-digitalis steroidal structure by suitable modifications of the 5alpha,14alpha-androstane skeleton. The strong hydrophobic interaction of the digitalis or cassaine polycyclic cores can be effectively obtained with the androstane skeleton taken in a reversed orientation. Thus, oxidation of C-6 and introduction in the C-3 position of the potent pharmacophoric group recently introduced by us, in the 17 position of the digitalis skeleton, namely, O-(omega-aminoalkyl)oxime, led to a series of substituted androstanes able to inhibit the Na(+),K(+)-ATPase, most of them with an IC(50) in the low micromolar level, and to induce a positive inotropic effect in guinea pig. Within this series, androstane-3,6,17-trione (E,Z)-3-(2-aminoethyl)oxime (22b, PST 2744) induced a strong positive inotropic effect while being less arrhythmogenic than digoxin, when the two compounds were compared at equiinotropic doses.
|
Inhibition of P-gp was determined using rhodamine-assay in human CaCo-2 cells
|
None
|
1.0
%
|
|
Journal : J. Med. Chem.
Title : Comparison of in vitro P-glycoprotein screening assays: recommendations for their use in drug discovery.
Year : 2003
Volume : 46
Issue : 9
First Page : 1716
Last Page : 1725
Authors : Schwab D, Fischer H, Tabatabaei A, Poli S, Huwyler J.
Abstract : The ATP-dependent drug efflux pump P-glycoprotein (P-gp) affects the absorption and disposition of many compounds. P-gp may also play role in clinically significant drug-drug interactions. Therefore, it is important to find potential substrates or inhibitors of P-gp early in the drug discovery process. To identify compounds that interact with this transporter, several P-gp assays were validated and compared by testing a set of 28 reference compounds, including inhibitors of cytochrome P450 3A4 (CYP3A4). The assays included in silico predictions, inhibition assays (based on cellular uptake of rhodamine-123 or calcein AM), and functional assays (ATPase activity assay and transcellular transport assay, the latter for a subset of compounds). In addition, species differences were studied in an indirect fluorescence indicator screening assay and test systems expressing porcine, mouse, or human P-gp. Our results suggest that several P-gp assays should be used in combination to classify compounds as substrates or inhibitors of P-gp. Recommendations are given on screening strategies which can be applied to different phases of the drug discovery and development process.
|
Concentration of compound producing 50% of the maximal increase in force of contraction in electrically driven guinea pig left atrium
|
Cavia porcellus
|
380.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and inotropic activity of 1-(O-aminoalkyloximes) of perhydroindene derivatives as simplified digitalis-like compounds acting on the Na(+),K(+)-ATPase.
Year : 2002
Volume : 45
Issue : 1
First Page : 189
Last Page : 207
Authors : Cerri A, Almirante N, Barassi P, Benicchio A, De Munari S, Marazzi G, Molinari I, Serra F, Melloni P.
Abstract : A series of 5-substituted (3aS,7aR)-7a-methylperhydroinden-3a-ol derivatives bearing a 1(S)-(omega-aminoalkoxy)iminoalkyl or -alkenyl substituent was synthesized, starting from the Hajos-Parrish ketol 47, as simplified analogues of very potent 17beta-aminoalkyloximes with digitalis skeleton, previously reported. The target compounds were evaluated in vitro for displacement of the specific [3H]ouabain binding from the dog kidney Na(+),K(+)-ATPase receptor. Some of them revealed IC(50) values in the micromolar range. The most active compounds possess a cyclohexyl group in the 5(S) position and in position 1(S) the same aminoalkyloxime groups already reported for the digitoxigenin-like series in position 17beta. Although the ring conformation of these derivatives was comparable to that of uzarigenin, the binding affinities of the most active ones were 4/8-fold lower in comparison to that standard. Three compounds among those with the highest affinities were assayed in vitro for their inotropic activity on an electrically driven guinea pig left atrium and were found to be less potent than both digoxin, the most widely used inotropic agent, and the corresponding digitalis 17beta-aminoalkyloximes.
|
Inhibition of dog kidney Na+,K+-ATPase by [32P]ATP hydrolysis method
|
Canis lupus familiaris
|
220.0
nM
|
|
Journal : J. Med. Chem.
Title : Novel analogues of istaroxime, a potent inhibitor of Na+,K+-ATPase: synthesis and structure-activity relationship.
Year : 2008
Volume : 51
Issue : 15
First Page : 4601
Last Page : 4608
Authors : Gobbini M, Armaroli S, Banfi L, Benicchio A, Carzana G, Fedrizzi G, Ferrari P, Giacalone G, Giubileo M, Marazzi G, Micheletti R, Moro B, Pozzi M, Scotti PE, Torri M, Cerri A.
Abstract : We report the synthesis and biological properties of novel inhibitors of the Na(+),K(+)-ATPase as positive inotropic compounds. Following our previously described model from which Istaroxime was generated, the 5alpha,14alpha-androstane skeleton was used as a scaffold to study the space around the basic chain of our lead compound. Some compounds demonstrated higher potencies than Istaroxime on the receptor and the (E)-3-[(R)-3-pyrrolidinyl]oxime derivative, 15, was the most potent; as further confirmation of our model, the E isomers of the oxime are more potent than the Z form. The compounds tested in the guinea pig model induced positive inotropic effects, which are correlated to the in vitro inhibitory potency on the Na(+),K(+)-ATPase. The finding that all tested compounds resulted less proarrhythmogenic than digoxin, a currently clinically used positive inotropic agent, suggests that this could be a feature of the 3-aminoalkyloxime derivative class of 5alpha,14alpha-androstane.
|
Inhibition of 4-(4-(dimethylamino)styryl)-N-methylpyridinium uptake at human OCT1 expressed in HEK293 cells at 100 uM by confocal microscopy
|
Homo sapiens
|
46.9
%
|
|
Journal : J. Med. Chem.
Title : Structural requirements for drug inhibition of the liver specific human organic cation transport protein 1.
Year : 2008
Volume : 51
Issue : 19
First Page : 5932
Last Page : 5942
Authors : Ahlin G, Karlsson J, Pedersen JM, Gustavsson L, Larsson R, Matsson P, Norinder U, Bergström CA, Artursson P.
Abstract : The liver-specific organic cation transport protein (OCT1; SLC22A1) transports several cationic drugs including the antidiabetic drug metformin and the anticancer agents oxaliplatin and imatinib. In this study, we explored the chemical space of registered oral drugs with the aim of studying the inhibition pattern of OCT1 and of developing predictive computational models of OCT1 inhibition. In total, 191 structurally diverse compounds were examined in HEK293-OCT1 cells. The assay identified 47 novel inhibitors and confirmed 15 previously known inhibitors. The enrichment of OCT1 inhibitors was seen in several drug classes including antidepressants. High lipophilicity and a positive net charge were found to be the key physicochemical properties for OCT1 inhibition, whereas a high molecular dipole moment and many hydrogen bonds were negatively correlated to OCT1 inhibition. The data were used to generate OPLS-DA models for OCT1 inhibitors; the final model correctly predicted 82% of the inhibitors and 88% of the noninhibitors of the test set.
|
Cytotoxicity against human TK10 cells after 48 hrs by SRB assay
|
Homo sapiens
|
14.6
nM
|
|
Journal : J. Nat. Prod.
Title : Digitoxin inhibits the growth of cancer cell lines at concentrations commonly found in cardiac patients.
Year : 2005
Volume : 68
Issue : 11
First Page : 1642
Last Page : 1645
Authors : López-Lázaro M, Pastor N, Azrak SS, Ayuso MJ, Austin CA, Cortés F.
Abstract : The cardiac glycosides digitoxin (1) and digoxin (3) have been used in cardiac diseases for many years. During this time several reports have suggested the possible use of digitalis in medical oncology. Several analogues of digitoxin (1) were evaluated for growth inhibition activity in three human cancer cell lines; this study showed that digitoxin (1) was the most active compound and revealed some structural features that may play a role in the growth inhibition activity of these drugs. The IC50 values for 1 (3-33 nM) were within or below the concentration range seen in the plasma of patients with cardiac disease receiving this glycoside (20-33 nM). A renal adenocarcinoma cancer cell line (TK-10) was hypersensitive to this drug, and digitoxin toxicity on these cells was mediated by apoptosis. In vitro experiments showed that 1 at 30 nM induced levels of DNA-topoisomerase II cleavable complexes similar to etoposide, a topoisomerase II poison widely used in cancer chemotherapy. Using the individual cell assay TARDIS, cells exposed to 1 for 30 min showed low but statistically significant levels of DNA-topoisomerase II cleavable complexes; however these complexes disappeared after 24 h exposure.
|
Cytotoxicity against human MCF7 cells after 48 hrs by SRB assay
|
Homo sapiens
|
24.1
nM
|
|
Journal : J. Nat. Prod.
Title : Digitoxin inhibits the growth of cancer cell lines at concentrations commonly found in cardiac patients.
Year : 2005
Volume : 68
Issue : 11
First Page : 1642
Last Page : 1645
Authors : López-Lázaro M, Pastor N, Azrak SS, Ayuso MJ, Austin CA, Cortés F.
Abstract : The cardiac glycosides digitoxin (1) and digoxin (3) have been used in cardiac diseases for many years. During this time several reports have suggested the possible use of digitalis in medical oncology. Several analogues of digitoxin (1) were evaluated for growth inhibition activity in three human cancer cell lines; this study showed that digitoxin (1) was the most active compound and revealed some structural features that may play a role in the growth inhibition activity of these drugs. The IC50 values for 1 (3-33 nM) were within or below the concentration range seen in the plasma of patients with cardiac disease receiving this glycoside (20-33 nM). A renal adenocarcinoma cancer cell line (TK-10) was hypersensitive to this drug, and digitoxin toxicity on these cells was mediated by apoptosis. In vitro experiments showed that 1 at 30 nM induced levels of DNA-topoisomerase II cleavable complexes similar to etoposide, a topoisomerase II poison widely used in cancer chemotherapy. Using the individual cell assay TARDIS, cells exposed to 1 for 30 min showed low but statistically significant levels of DNA-topoisomerase II cleavable complexes; however these complexes disappeared after 24 h exposure.
|
Cytotoxicity against human UACC62 cells after 48 hrs by SRB assay
|
Homo sapiens
|
29.5
nM
|
|
Journal : J. Nat. Prod.
Title : Digitoxin inhibits the growth of cancer cell lines at concentrations commonly found in cardiac patients.
Year : 2005
Volume : 68
Issue : 11
First Page : 1642
Last Page : 1645
Authors : López-Lázaro M, Pastor N, Azrak SS, Ayuso MJ, Austin CA, Cortés F.
Abstract : The cardiac glycosides digitoxin (1) and digoxin (3) have been used in cardiac diseases for many years. During this time several reports have suggested the possible use of digitalis in medical oncology. Several analogues of digitoxin (1) were evaluated for growth inhibition activity in three human cancer cell lines; this study showed that digitoxin (1) was the most active compound and revealed some structural features that may play a role in the growth inhibition activity of these drugs. The IC50 values for 1 (3-33 nM) were within or below the concentration range seen in the plasma of patients with cardiac disease receiving this glycoside (20-33 nM). A renal adenocarcinoma cancer cell line (TK-10) was hypersensitive to this drug, and digitoxin toxicity on these cells was mediated by apoptosis. In vitro experiments showed that 1 at 30 nM induced levels of DNA-topoisomerase II cleavable complexes similar to etoposide, a topoisomerase II poison widely used in cancer chemotherapy. Using the individual cell assay TARDIS, cells exposed to 1 for 30 min showed low but statistically significant levels of DNA-topoisomerase II cleavable complexes; however these complexes disappeared after 24 h exposure.
|
Cytotoxicity against human K562 cells by XTT assay
|
Homo sapiens
|
28.2
nM
|
|
Journal : J. Nat. Prod.
Title : Digitoxin inhibits the growth of cancer cell lines at concentrations commonly found in cardiac patients.
Year : 2005
Volume : 68
Issue : 11
First Page : 1642
Last Page : 1645
Authors : López-Lázaro M, Pastor N, Azrak SS, Ayuso MJ, Austin CA, Cortés F.
Abstract : The cardiac glycosides digitoxin (1) and digoxin (3) have been used in cardiac diseases for many years. During this time several reports have suggested the possible use of digitalis in medical oncology. Several analogues of digitoxin (1) were evaluated for growth inhibition activity in three human cancer cell lines; this study showed that digitoxin (1) was the most active compound and revealed some structural features that may play a role in the growth inhibition activity of these drugs. The IC50 values for 1 (3-33 nM) were within or below the concentration range seen in the plasma of patients with cardiac disease receiving this glycoside (20-33 nM). A renal adenocarcinoma cancer cell line (TK-10) was hypersensitive to this drug, and digitoxin toxicity on these cells was mediated by apoptosis. In vitro experiments showed that 1 at 30 nM induced levels of DNA-topoisomerase II cleavable complexes similar to etoposide, a topoisomerase II poison widely used in cancer chemotherapy. Using the individual cell assay TARDIS, cells exposed to 1 for 30 min showed low but statistically significant levels of DNA-topoisomerase II cleavable complexes; however these complexes disappeared after 24 h exposure.
|
Cytotoxicity against human CC20 cells after 72 hrs by FMCA method
|
Homo sapiens
|
240.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic effects of cardiac glycosides in colon cancer cells, alone and in combination with standard chemotherapeutic drugs.
Year : 2009
Volume : 72
Issue : 11
First Page : 1969
Last Page : 1974
Authors : Felth J, Rickardson L, Rosén J, Wickström M, Fryknäs M, Lindskog M, Bohlin L, Gullbo J.
Abstract : Cardiac glycosides have been reported to exhibit cytotoxic activity against several different cancer types, but studies against colorectal cancer are lacking. In a screening procedure aimed at identifying natural products with activity against colon cancer, several cardiac glycosides were shown to be of interest, and five of these were further evaluated in different colorectal cancer cell lines and primary cells from patients. Convallatoxin (1), oleandrin (4), and proscillaridin A (5) were identified as the most potent compounds (submicromolar IC50 values), and digitoxin (2) and digoxin (3), which are used in cardiac disease, exhibited somewhat lower activity (IC50 values 0.27-4.1 microM). Selected cardiac glycosides were tested in combination with four clinically relevant cytotoxic drugs (5-fluorouracil, oxaliplatin, cisplatin, irinotecan). The combination of 2 and oxaliplatin exhibited synergism including the otherwise highly drug-resistant HT29 cell line. A ChemGPS-NP application comparing modes of action of anticancer drugs identified cardiac glycosides as a separate cluster. These findings demonstrate that such substances may exhibit significant activity against colorectal cancer cell lines, by mechanisms disparate from currently used anticancer drugs, but at concentrations generally considered not achievable in patient plasma.
|
Cytotoxicity against human HCT116 cells after 72 hrs by FMCA method
|
Homo sapiens
|
270.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic effects of cardiac glycosides in colon cancer cells, alone and in combination with standard chemotherapeutic drugs.
Year : 2009
Volume : 72
Issue : 11
First Page : 1969
Last Page : 1974
Authors : Felth J, Rickardson L, Rosén J, Wickström M, Fryknäs M, Lindskog M, Bohlin L, Gullbo J.
Abstract : Cardiac glycosides have been reported to exhibit cytotoxic activity against several different cancer types, but studies against colorectal cancer are lacking. In a screening procedure aimed at identifying natural products with activity against colon cancer, several cardiac glycosides were shown to be of interest, and five of these were further evaluated in different colorectal cancer cell lines and primary cells from patients. Convallatoxin (1), oleandrin (4), and proscillaridin A (5) were identified as the most potent compounds (submicromolar IC50 values), and digitoxin (2) and digoxin (3), which are used in cardiac disease, exhibited somewhat lower activity (IC50 values 0.27-4.1 microM). Selected cardiac glycosides were tested in combination with four clinically relevant cytotoxic drugs (5-fluorouracil, oxaliplatin, cisplatin, irinotecan). The combination of 2 and oxaliplatin exhibited synergism including the otherwise highly drug-resistant HT29 cell line. A ChemGPS-NP application comparing modes of action of anticancer drugs identified cardiac glycosides as a separate cluster. These findings demonstrate that such substances may exhibit significant activity against colorectal cancer cell lines, by mechanisms disparate from currently used anticancer drugs, but at concentrations generally considered not achievable in patient plasma.
|
Cytotoxicity against human colon cancer cells after 72 hrs by FMCA method
|
Homo sapiens
|
100.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic effects of cardiac glycosides in colon cancer cells, alone and in combination with standard chemotherapeutic drugs.
Year : 2009
Volume : 72
Issue : 11
First Page : 1969
Last Page : 1974
Authors : Felth J, Rickardson L, Rosén J, Wickström M, Fryknäs M, Lindskog M, Bohlin L, Gullbo J.
Abstract : Cardiac glycosides have been reported to exhibit cytotoxic activity against several different cancer types, but studies against colorectal cancer are lacking. In a screening procedure aimed at identifying natural products with activity against colon cancer, several cardiac glycosides were shown to be of interest, and five of these were further evaluated in different colorectal cancer cell lines and primary cells from patients. Convallatoxin (1), oleandrin (4), and proscillaridin A (5) were identified as the most potent compounds (submicromolar IC50 values), and digitoxin (2) and digoxin (3), which are used in cardiac disease, exhibited somewhat lower activity (IC50 values 0.27-4.1 microM). Selected cardiac glycosides were tested in combination with four clinically relevant cytotoxic drugs (5-fluorouracil, oxaliplatin, cisplatin, irinotecan). The combination of 2 and oxaliplatin exhibited synergism including the otherwise highly drug-resistant HT29 cell line. A ChemGPS-NP application comparing modes of action of anticancer drugs identified cardiac glycosides as a separate cluster. These findings demonstrate that such substances may exhibit significant activity against colorectal cancer cell lines, by mechanisms disparate from currently used anticancer drugs, but at concentrations generally considered not achievable in patient plasma.
|
Inhibition of dog kidney Na+K+-ATPase assessed as hydrolysis of [32P]ATP
|
Canis lupus familiaris
|
310.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Novel analogues of Istaroxime, a potent inhibitor of Na(+),K(+)-ATPase: Synthesis, structure-activity relationship and 3D-quantitative structure-activity relationship of derivatives at position 6 on the androstane scaffold.
Year : 2010
Volume : 18
Issue : 12
First Page : 4275
Last Page : 4299
Authors : Gobbini M, Armaroli S, Banfi L, Benicchio A, Carzana G, Ferrari P, Giacalone G, Marazzi G, Moro B, Micheletti R, Sputore S, Torri M, Zappavigna MP, Cerri A.
Abstract : We report the synthesis and biological properties of novel analogues of Istaroxime acting as positive inotropic compounds through the inhibition of the Na(+),K(+)-ATPase. We explored the chemical space around the position 6 of the steroidal scaffold by changing the functional groups at that position and maintaining a basic oximic chain in position 3. Some compounds showed inhibitory potencies of the Na(+),K(+)-ATPase higher than Istaroxime and many of the compounds tested in vivo were safer than digoxin, the classic digitalis compound currently used for the treatment of congestive heart failure as inotropic agent. The 3D-QSAR analyses using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods have been successfully applied to a set of 63 androstane derivatives as Na(+),K(+)-ATPase inhibitors. The contour plots provide many useful insights into relationships between structural features and inhibitory potency.
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based HTS Dose Confirmation to Identify Inhibitors of of 5'UTR Stem-Loop Driven Alpha-Synuclein mRNA Translation in H4 Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1813 (Primary HTS), 1827 (Project Summary)]
|
None
|
30.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based Dose Response HTS to Identify Inhibitors of Luciferase Translation or Activity in H4 Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1813 (Primary HTS), 1827 (Project Summary)]
|
None
|
100.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based Dose Response to Identify Inhibitors of Luciferase Translation or Activity in H4-C Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1813 (Primary HTS), 1827 (Project Summary)]
|
None
|
34.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based Dose Response to Identify Inhibitors of 5'UTR Stem-Loop Driven Prion Protein mRNA Translation in H4-C Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1827 (Project Summary), 1813 (Primary HTS)]
|
None
|
40.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based Dose Response HTS to Identify Inhibitors of 5'UTR Stem-Loop Driven Prion Protein mRNA Translation in H4 Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1827 (Project Summary), 1813 (Primary HTS)]
|
None
|
100.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Luminescence Cell-Based Dose Confirmation HTS to Identify Inhibitors of of 5'UTR Stem-Loop Driven Alpha-Synuclein mRNA Translation in H4 Neuroglioblastoma Cells. (Class of assay: confirmatory) [Related pubchem assays: 1827 (Project Summary), 1813 (Primary HTS)]
|
None
|
100.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: A Cell-Based Confirmatory Screen for Compounds that Inhibit VEEV, TC-83. (Class of assay: confirmatory) [Related pubchem assays (depositor defined):AID588723]
|
Chlorocebus sabaeus
|
50.0
nM
|
|
Title : PubChem BioAssay data set
|
PUBCHEM_BIOASSAY: Fluorescence Cell-Based Dose Response to Characterize Compounds Cytotoxic to RAS-Dependent BJ-TERT-LT-ST Fibroblast. (Class of assay: confirmatory) [Related pubchem assays (depositor defined):AID1554, AID1674]
|
None
|
104.0
nM
|
|
PUBCHEM_BIOASSAY: Fluorescence Cell-Based Dose Response to Characterize Compounds Cytotoxic to RAS-Dependent BJ-TERT-LT-ST Fibroblast. (Class of assay: confirmatory) [Related pubchem assays (depositor defined):AID1554, AID1674]
|
None
|
104.0
nM
|
|
Title : PubChem BioAssay data set
|
Cytotoxicity against human T47D cells after 72 hrs by CellTiter-Glo assay
|
Homo sapiens
|
660.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic cardiac glycosides and other compounds from Asclepias syriaca.
Year : 2012
Volume : 75
Issue : 3
First Page : 400
Last Page : 407
Authors : Araya JJ, Kindscher K, Timmermann BN.
Abstract : Phytochemical investigation of the dried biomass of Asclepias syriaca afforded five new compounds (1-5), along with 19 known structures. Overall, the secondary metabolites isolated and identified from this plant showed a wide structural diversity including pentacyclic triterpenes, cardiac glycosides, flavonoid glycosides, lignans, a phenylethanoid, and a glycosylated megastigmane. In addition, the isolates were tested against the cancer breast cell line Hs578T, and those showing IC(50) values lower than 50 μM (1 and 6-9) were further investigated in three additional breast cancer cell lines (MCF-7, T47D, and Sk-Br-3) and the normal breast cell line Hs578Bst.
|
Cytotoxicity against human Hs578T cells after 72 hrs by CellTiter-Glo assay
|
Homo sapiens
|
251.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic cardiac glycosides and other compounds from Asclepias syriaca.
Year : 2012
Volume : 75
Issue : 3
First Page : 400
Last Page : 407
Authors : Araya JJ, Kindscher K, Timmermann BN.
Abstract : Phytochemical investigation of the dried biomass of Asclepias syriaca afforded five new compounds (1-5), along with 19 known structures. Overall, the secondary metabolites isolated and identified from this plant showed a wide structural diversity including pentacyclic triterpenes, cardiac glycosides, flavonoid glycosides, lignans, a phenylethanoid, and a glycosylated megastigmane. In addition, the isolates were tested against the cancer breast cell line Hs578T, and those showing IC(50) values lower than 50 μM (1 and 6-9) were further investigated in three additional breast cancer cell lines (MCF-7, T47D, and Sk-Br-3) and the normal breast cell line Hs578Bst.
|
Cytotoxicity against human Hs578Bst cells after 72 hrs by CellTiter-Glo assay
|
Homo sapiens
|
40.0
nM
|
|
Journal : J. Nat. Prod.
Title : Cytotoxic cardiac glycosides and other compounds from Asclepias syriaca.
Year : 2012
Volume : 75
Issue : 3
First Page : 400
Last Page : 407
Authors : Araya JJ, Kindscher K, Timmermann BN.
Abstract : Phytochemical investigation of the dried biomass of Asclepias syriaca afforded five new compounds (1-5), along with 19 known structures. Overall, the secondary metabolites isolated and identified from this plant showed a wide structural diversity including pentacyclic triterpenes, cardiac glycosides, flavonoid glycosides, lignans, a phenylethanoid, and a glycosylated megastigmane. In addition, the isolates were tested against the cancer breast cell line Hs578T, and those showing IC(50) values lower than 50 μM (1 and 6-9) were further investigated in three additional breast cancer cell lines (MCF-7, T47D, and Sk-Br-3) and the normal breast cell line Hs578Bst.
|
TP_TRANSPORTER: inhibition of E217betaG uptake in Oatp2-expressing LLC-PK1 cells
|
None
|
37.0
nM
|
|
Journal : J. Pharmacol. Exp. Ther.
Title : Characterization of the efflux transport of 17beta-estradiol-D-17beta-glucuronide from the brain across the blood-brain barrier.
Year : 2001
Volume : 298
Issue : 1
First Page : 316
Last Page : 322
Authors : Sugiyama D, Kusuhara H, Shitara Y, Abe T, Meier PJ, Sekine T, Endou H, Suzuki H, Sugiyama Y.
Abstract : The contribution of organic anion transporters to the total efflux of 17beta-estradiol-D-17beta-glucuronide (E(2)17betaG) through the blood-brain barrier (BBB) was investigated using the Brain Efflux Index method by examining the inhibitory effects of probenecid, taurocholate (TCA), p-aminohippurate (PAH), and digoxin. E(2)17betaG was eliminated through the BBB with a rate constant of 0.037 min(-1) after the microinjection into the brain. Probenecid and TCA inhibited this elimination with an IC50 value of 34 and 1.8 nmol/0.5 microl of injectate, respectively, whereas PAH and digoxin reduced the total efflux to about 80 and 60% of the control value, respectively. The selectivity of these inhibitors was confirmed by examining their inhibitory effects on the transport via organic anion transporting polypeptide 1 (Oatp1), Oatp2, organic anion transporter 1 (Oat1), and Oat3 transfectants using LLC-PK1 cells as hosts. Digoxin specifically inhibited the transport via Oatp2 (K(i) = 0.037 microM). The K(i) values of TCA for Oatp1 and Oatp2 (11 and 39 microM, respectively) were about 20 times lower than those for Oat1 and Oat3 (2.8 and 0.8 mM, respectively). PAH did not affect the transport via the Oatp family, but had a similar affinity for Oat1 and Oat3 (85 and 300 microM, respectively). Probenecid had a similar affinity for these transporters (Oatp1, Oatp2, Oat1, and Oat3) examined in this study. Taking the selectivity of these inhibitors into consideration, the maximum contribution made by the Oatp2 and Oat family to the total efflux of E(2)17betaG from the brain appears to be about 40 and 20%, respectively.
|
TP_TRANSPORTER: inhibition of Taurocholate uptake in Oatp2-expressing LLC-PK1 cells
|
None
|
580.0
nM
|
|
Journal : Drug Metab. Dispos.
Title : Effect of 17 beta-estradiol-D-17 beta-glucuronide on the rat organic anion transporting polypeptide 2-mediated transport differs depending on substrates.
Year : 2002
Volume : 30
Issue : 1
First Page : 220
Last Page : 223
Authors : Sugiyama D, Kusuhara H, Shitara Y, Abe T, Sugiyama Y.
Abstract : Rat organic anion transporting polypeptide 2 (rOatp2) is a member of the OATP family. It exhibits broad substrate specificity and accepts amphipathic organic anions, cardiac glycosides (digoxin and ouabain; a neutral compound), and organic cations (rocuronium and N-(4,4-azo-n-pentyl)-21-deoxyajamalinium). In the present study, kinetic analyses were carried out to investigate whether taurocholate (TCA), digoxin, and 17beta-estradiol-D-17beta-glucuronide (E(2)17betaG) share the same recognition site on rOatp2 for their transport. The transport of TCA and digoxin was mutually inhibited, and the K(i) values of digoxin and TCA for the transport of TCA and digoxin were 0.58 and 160 microM, respectively. The K(m) and V(max) values of TCA and digoxin were 190 microM and 140 pmol/min/mg of protein and 1.1 microM and 6.6 pmol/min/mg of protein, respectively. The K(m) and K(i) values were consistent. In addition, digoxin (1 microM) and TCA (100 microM) increased the K(m) values of TCA and digoxin, respectively, but they did not affect the V(max) values, suggesting that their inhibition is competitive. The transport of digoxin via rOatp2 was inhibited slightly by E(2)17betaG, whereas the uptake of TCA was stimulated by E(2)17betaG in a concentration-dependent manner. These results suggest that rOatp2 has at least two substrate recognition sites, one for TCA and digoxin and the other for E(2)17betaG.
|
Inhibition of human liver OATP1B1 expressed in HEK293 Flp-In cells assessed as reduction in E17-betaG uptake at 20 uM by scintillation counting
|
Homo sapiens
|
36.0
%
|
|
Journal : J. Med. Chem.
Title : Classification of inhibitors of hepatic organic anion transporting polypeptides (OATPs): influence of protein expression on drug-drug interactions.
Year : 2012
Volume : 55
Issue : 10
First Page : 4740
Last Page : 4763
Authors : Karlgren M, Vildhede A, Norinder U, Wisniewski JR, Kimoto E, Lai Y, Haglund U, Artursson P.
Abstract : The hepatic organic anion transporting polypeptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug-drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors.
|
Inhibition of human liver OATP1B3 expressed in HEK293 Flp-In cells assessed as reduction in [3H]E17-betaG uptake at 20 uM incubated for 5 mins by scintillation counting
|
Homo sapiens
|
-4.7
%
|
|
Journal : J. Med. Chem.
Title : Classification of inhibitors of hepatic organic anion transporting polypeptides (OATPs): influence of protein expression on drug-drug interactions.
Year : 2012
Volume : 55
Issue : 10
First Page : 4740
Last Page : 4763
Authors : Karlgren M, Vildhede A, Norinder U, Wisniewski JR, Kimoto E, Lai Y, Haglund U, Artursson P.
Abstract : The hepatic organic anion transporting polypeptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug-drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors.
|
Inhibition of human liver OATP2B1 expressed in HEK293 Flp-In cells assessed as reduction in [3H]E3S uptake at 20 uM incubated for 5 mins by scintillation counting
|
Homo sapiens
|
32.1
%
|
|
Journal : J. Med. Chem.
Title : Classification of inhibitors of hepatic organic anion transporting polypeptides (OATPs): influence of protein expression on drug-drug interactions.
Year : 2012
Volume : 55
Issue : 10
First Page : 4740
Last Page : 4763
Authors : Karlgren M, Vildhede A, Norinder U, Wisniewski JR, Kimoto E, Lai Y, Haglund U, Artursson P.
Abstract : The hepatic organic anion transporting polypeptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug-drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors.
|
Cytotoxicity against human SK-MEL-28 cells after 3 days by MTT assay
|
Homo sapiens
|
266.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Cytotoxicity against human U373 cells after 3 days by MTT assay
|
Homo sapiens
|
146.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Cytotoxicity against human A549 cells after 3 days by MTT assay
|
Homo sapiens
|
50.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Cytotoxicity against human PC3 cells after 3 days by MTT assay
|
Homo sapiens
|
75.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Cytotoxicity against human MCF7 cells after 3 days by MTT assay
|
Homo sapiens
|
426.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Cytotoxicity against human Hs683 cells after 3 days by MTT assay
|
Homo sapiens
|
40.0
nM
|
|
Journal : J. Nat. Prod.
Title : Structure-activity relationship analysis of bufadienolide-induced in vitro growth inhibitory effects on mouse and human cancer cells.
Year : 2013
Volume : 76
Issue : 6
First Page : 1078
Last Page : 1084
Authors : Moreno Y Banuls L, Urban E, Gelbcke M, Dufrasne F, Kopp B, Kiss R, Zehl M.
Abstract : The in vitro growth inhibitory effects of 27 bufadienolides and eight degradation products, with two cardenolides (ouabain and digoxin) chosen as reference compounds, were analyzed by means of an MTT colorimetric assay in six human and two mouse cancer cell lines. A structure-activity analysis was then performed to highlight the most important substituents relating to the in vitro growth inhibitory activity of bufadienolides in cancer cells. Thus, the current study revealed that various bufadienolides, including gamabufotalin rhamnoside (1a), bufotalin (2a), and hellebrin (3a), displayed higher growth inhibitory activities for various human cancer cell lines when compared to ouabain and digoxin. Gamabufotalin rhamnoside (1a) was the only compound that displayed growth inhibitory effects of <1 μM in mouse cancer cells that expressed mutated forms of the Na(+),K(+)-ATPase α-1 subunit. In addition, all genins and degradation products displayed weaker (if any) in vitro growth inhibitory effects on cancer cells when compared to their respective glycosylated homologue, with the exception of hellebrigenin (3b), which was as active as hellebrin (3a).
|
Inhibition of sodium fluorescein uptake in OATP1B1-transfected CHO cells at an equimolar substrate-inhibitor concentration of 10 uM
|
Cricetulus griseus
|
81.25
%
|
|
Journal : Mol. Pharmacol.
Title : Structure-based identification of OATP1B1/3 inhibitors.
Year : 2013
Volume : 83
Issue : 6
First Page : 1257
Last Page : 1267
Authors : De Bruyn T, van Westen GJ, Ijzerman AP, Stieger B, de Witte P, Augustijns PF, Annaert PP.
Abstract : Several recent studies show that inhibition of the hepatic transport proteins organic anion-transporting polypeptide 1B1 (OATP1B1) and 1B3 (OATP1B3) can result in clinically relevant drug-drug interactions (DDI). To avoid late-stage development drug failures due to OATP1B-mediated DDI, predictive in vitro and in silico methods should be implemented at an early stage of the drug candidate evaluation process. In the present study, we first developed a high-throughput in vitro transporter inhibition assay for the OATP1B subfamily. A total of 2000 compounds were tested as potential modulators of the uptake of the OATP1B substrate sodium fluorescein, in OATP1B1- or 1B3-transfected Chinese hamster ovary cells. At an equimolar substrate-inhibitor concentration of 10 µM, 212 and 139 molecules were identified as OATP1B1 and OATP1B3 inhibitors, respectively (minimum 50% inhibition). For 69 compounds, previously not identified as OATP1B inhibitors, concentration-dependent inhibition was also determined, yielding Ki values ranging from 0.06 to 6.5 µM. Based on these in vitro data, we subsequently developed a proteochemometrics-based in silico model, which predicted OATP1B inhibitors in the test group (20% of the dataset) with high specificity (86%) and sensitivity (78%). Moreover, several physicochemical compound properties and substructures related to OATP1B1/1B3 inhibition or inactivity were identified. Finally, model performance was prospectively verified with a set of 54 compounds not included in the original dataset. This validation indicated that 80 and 74% of the compounds were correctly classified for OATP1B1 and OATP1B3 inhibition, respectively.
|
Inhibition of sodium fluorescein uptake in OATP1B3-transfected CHO cells at an equimolar substrate-inhibitor concentration of 10 uM
|
Cricetulus griseus
|
75.88
%
|
|
Journal : Mol. Pharmacol.
Title : Structure-based identification of OATP1B1/3 inhibitors.
Year : 2013
Volume : 83
Issue : 6
First Page : 1257
Last Page : 1267
Authors : De Bruyn T, van Westen GJ, Ijzerman AP, Stieger B, de Witte P, Augustijns PF, Annaert PP.
Abstract : Several recent studies show that inhibition of the hepatic transport proteins organic anion-transporting polypeptide 1B1 (OATP1B1) and 1B3 (OATP1B3) can result in clinically relevant drug-drug interactions (DDI). To avoid late-stage development drug failures due to OATP1B-mediated DDI, predictive in vitro and in silico methods should be implemented at an early stage of the drug candidate evaluation process. In the present study, we first developed a high-throughput in vitro transporter inhibition assay for the OATP1B subfamily. A total of 2000 compounds were tested as potential modulators of the uptake of the OATP1B substrate sodium fluorescein, in OATP1B1- or 1B3-transfected Chinese hamster ovary cells. At an equimolar substrate-inhibitor concentration of 10 µM, 212 and 139 molecules were identified as OATP1B1 and OATP1B3 inhibitors, respectively (minimum 50% inhibition). For 69 compounds, previously not identified as OATP1B inhibitors, concentration-dependent inhibition was also determined, yielding Ki values ranging from 0.06 to 6.5 µM. Based on these in vitro data, we subsequently developed a proteochemometrics-based in silico model, which predicted OATP1B inhibitors in the test group (20% of the dataset) with high specificity (86%) and sensitivity (78%). Moreover, several physicochemical compound properties and substructures related to OATP1B1/1B3 inhibition or inactivity were identified. Finally, model performance was prospectively verified with a set of 54 compounds not included in the original dataset. This validation indicated that 80 and 74% of the compounds were correctly classified for OATP1B1 and OATP1B3 inhibition, respectively.
|
Displacement of [3H]25-hydroxycholesterol from human RORc-LBD expressed in bacterial expression system after 3 hrs by scintillation counting analysis
|
Homo sapiens
|
109.0
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : A reversed sulfonamide series of selective RORc inverse agonists.
Year : 2014
Volume : 24
Issue : 24
First Page : 5769
Last Page : 5776
Authors : van Niel MB, Fauber BP, Cartwright M, Gaines S, Killen JC, René O, Ward SI, de Leon Boenig G, Deng Y, Eidenschenk C, Everett C, Gancia E, Ganguli A, Gobbi A, Hawkins J, Johnson AR, Kiefer JR, La H, Lockey P, Norman M, Ouyang W, Qin A, Wakes N, Waszkowycz B, Wong H.
Abstract : The identification of a new series of RORc inverse agonists is described. Comprehensive structure-activity relationship studies of this reversed sulfonamide series identified potent RORc inverse agonists in biochemical and cellular assays which were also selective against a panel of nuclear receptors. Our work has contributed a compound that may serve as a useful in vitro tool to delineate the complex biological pathways involved in signalling through RORc. An X-ray co-crystal structure of an analogue with RORc has also provided useful insights into the binding interactions of the new series.
|
Permeability in human Caco2 cells assessed as 11 uM BCRP inhibitor Ko134-mediated inhibition of digoxin at 5 uM by liquid scintillation counting
|
Homo sapiens
|
50.0
%
|
|
Journal : Drug Metab. Dispos.
Title : Characterization of efflux transporters involved in distribution and disposition of apixaban.
Year : 2013
Volume : 41
Issue : 4
First Page : 827
Last Page : 835
Authors : Zhang D, He K, Herbst JJ, Kolb J, Shou W, Wang L, Balimane PV, Han YH, Gan J, Frost CE, Humphreys WG.
Abstract : The studies reported here were conducted to investigate the transport characteristics of apixaban (1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide) and to understand the impact of transporters on apixaban distribution and disposition. In human permeability glycoprotein (P-gp)- and breast cancer resistance protein (BCRP)-cDNA-transfected cell monolayers as well as Caco-2 cell monolayers, the apparent efflux ratio of basolateral-to-apical (PcB-A) versus apical-to-basolateral permeability (PcA-B) of apixaban was >10. The P-gp- and BCRP-facilitated transport of apixaban was concentration- and time-dependent and did not show saturation over a wide range of concentrations (1-100 μM). The efflux transport of apixaban was also demonstrated by the lower mucosal-to-serosal permeability than that of the serosal-to-mucosal direction in isolated rat jejunum segments. Apixaban did not inhibit digoxin transport in Caco-2 cells. Ketoconazole decreased the P-gp-mediated apixaban efflux in Caco-2 and the P-gp-cDNA-transfected cell monolayers, but did not affect the apixaban efflux to a meaningful extent in the BCRP-cDNA-transfected cell monolayers. Coincubation of a P-gp inhibitor (ketoconazole or cyclosporin A) and a BCRP inhibitor (Ko134) provided more complete inhibition of apixaban efflux in Caco-2 cells than separate inhibition by individual inhibitors. Naproxen inhibited apixaban efflux in Caco-2 cells but showed only a minimal effect on apixaban transport in the BCRP-transfected cells. Naproxen was the first nonsteroidal antiinflammatory drug that was demonstrated as a weak P-gp inhibitor. These results demonstrate that apixaban is a substrate for efflux transporters P-gp and BCRP, which can help explain its low brain penetration, and low fetal exposures and high milk excretion in rats.
|
Apparent permeability in human Caco2 cells assessed as 50 uM P-gp inhibitor cyclosporin A-mediated inhibition of digoxin efflux at 5 uM by liquid scintillation counting
|
Homo sapiens
|
98.0
%
|
|
Journal : Drug Metab. Dispos.
Title : Characterization of efflux transporters involved in distribution and disposition of apixaban.
Year : 2013
Volume : 41
Issue : 4
First Page : 827
Last Page : 835
Authors : Zhang D, He K, Herbst JJ, Kolb J, Shou W, Wang L, Balimane PV, Han YH, Gan J, Frost CE, Humphreys WG.
Abstract : The studies reported here were conducted to investigate the transport characteristics of apixaban (1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide) and to understand the impact of transporters on apixaban distribution and disposition. In human permeability glycoprotein (P-gp)- and breast cancer resistance protein (BCRP)-cDNA-transfected cell monolayers as well as Caco-2 cell monolayers, the apparent efflux ratio of basolateral-to-apical (PcB-A) versus apical-to-basolateral permeability (PcA-B) of apixaban was >10. The P-gp- and BCRP-facilitated transport of apixaban was concentration- and time-dependent and did not show saturation over a wide range of concentrations (1-100 μM). The efflux transport of apixaban was also demonstrated by the lower mucosal-to-serosal permeability than that of the serosal-to-mucosal direction in isolated rat jejunum segments. Apixaban did not inhibit digoxin transport in Caco-2 cells. Ketoconazole decreased the P-gp-mediated apixaban efflux in Caco-2 and the P-gp-cDNA-transfected cell monolayers, but did not affect the apixaban efflux to a meaningful extent in the BCRP-cDNA-transfected cell monolayers. Coincubation of a P-gp inhibitor (ketoconazole or cyclosporin A) and a BCRP inhibitor (Ko134) provided more complete inhibition of apixaban efflux in Caco-2 cells than separate inhibition by individual inhibitors. Naproxen inhibited apixaban efflux in Caco-2 cells but showed only a minimal effect on apixaban transport in the BCRP-transfected cells. Naproxen was the first nonsteroidal antiinflammatory drug that was demonstrated as a weak P-gp inhibitor. These results demonstrate that apixaban is a substrate for efflux transporters P-gp and BCRP, which can help explain its low brain penetration, and low fetal exposures and high milk excretion in rats.
|
Apparent permeability in human Caco2 cells assessed as 50 uM P-gp inhibitor ketoconazole-mediated inhibition of digoxin efflux at 5 uM by liquid scintillation counting
|
Homo sapiens
|
100.0
%
|
|
Journal : Drug Metab. Dispos.
Title : Characterization of efflux transporters involved in distribution and disposition of apixaban.
Year : 2013
Volume : 41
Issue : 4
First Page : 827
Last Page : 835
Authors : Zhang D, He K, Herbst JJ, Kolb J, Shou W, Wang L, Balimane PV, Han YH, Gan J, Frost CE, Humphreys WG.
Abstract : The studies reported here were conducted to investigate the transport characteristics of apixaban (1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide) and to understand the impact of transporters on apixaban distribution and disposition. In human permeability glycoprotein (P-gp)- and breast cancer resistance protein (BCRP)-cDNA-transfected cell monolayers as well as Caco-2 cell monolayers, the apparent efflux ratio of basolateral-to-apical (PcB-A) versus apical-to-basolateral permeability (PcA-B) of apixaban was >10. The P-gp- and BCRP-facilitated transport of apixaban was concentration- and time-dependent and did not show saturation over a wide range of concentrations (1-100 μM). The efflux transport of apixaban was also demonstrated by the lower mucosal-to-serosal permeability than that of the serosal-to-mucosal direction in isolated rat jejunum segments. Apixaban did not inhibit digoxin transport in Caco-2 cells. Ketoconazole decreased the P-gp-mediated apixaban efflux in Caco-2 and the P-gp-cDNA-transfected cell monolayers, but did not affect the apixaban efflux to a meaningful extent in the BCRP-cDNA-transfected cell monolayers. Coincubation of a P-gp inhibitor (ketoconazole or cyclosporin A) and a BCRP inhibitor (Ko134) provided more complete inhibition of apixaban efflux in Caco-2 cells than separate inhibition by individual inhibitors. Naproxen inhibited apixaban efflux in Caco-2 cells but showed only a minimal effect on apixaban transport in the BCRP-transfected cells. Naproxen was the first nonsteroidal antiinflammatory drug that was demonstrated as a weak P-gp inhibitor. These results demonstrate that apixaban is a substrate for efflux transporters P-gp and BCRP, which can help explain its low brain penetration, and low fetal exposures and high milk excretion in rats.
|
Cytotoxicity against human RKO-AS45-1 cells after 48 hrs by MTT assay
|
Homo sapiens
|
420.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : γ-Benzylidene digoxin derivatives synthesis and molecular modeling: Evaluation of anticancer and the Na,K-ATPase activity effect.
Year : 2015
Volume : 23
Issue : 15
First Page : 4397
Last Page : 4404
Authors : Alves SL, Paixão N, Ferreira LG, Santos FR, Neves LD, Oliveira GC, Cortes VF, Salomé KS, Barison A, Santos FV, Cenzi G, Varotti FP, Oliveira SM, Taranto AG, Comar M, Silva LM, Noël F, Quintas LE, Barbosa LA, Villar JA.
Abstract : Cardiotonic steroids (CS), natural compounds with traditional use in cardiology, have been recently suggested to exert potent anticancer effects. However, the repertoire of molecules with Na,K-ATPase activity and anticancer properties is limited. This paper describes the synthesis of 6 new digoxin derivatives substituted (on the C17-butenolide) with γ-benzylidene group and their cytotoxic effect on human fibroblast (WI-26 VA4) and cancer (HeLa and RKO) cell lines as well as their effect on Na,K-ATPase activity and expression. As digoxin, compound BD-4 was almost 100-fold more potent than the other derivatives for cytotoxicity with the three types of cells used and was also the only one able to fully inhibit the Na,K-ATPase of HeLa cells after 24h treatment. No change in the Na,K-ATPase α1 isoform protein expression was detected. On the other hand it was 30-40 fold less potent for direct Na,K-ATPase inhibition, when compared to the most potent derivatives, BD-1 and BD-3, and digoxin. The data presented here demonstrated that the anticancer effect of digoxin derivatives substituted with γ-benzylidene were not related with their inhibition of Na,K-ATPase activity or alteration of its expression, suggesting that this classical molecular mechanism of CS is not involved in the cytotoxic effect of our derivatives.
|
Inhibition of human kidney Na(+)/K(+) ATPase alpha-1 assessed as amount of Pi release after 1 hr by colorimetric method
|
Homo sapiens
|
290.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : γ-Benzylidene digoxin derivatives synthesis and molecular modeling: Evaluation of anticancer and the Na,K-ATPase activity effect.
Year : 2015
Volume : 23
Issue : 15
First Page : 4397
Last Page : 4404
Authors : Alves SL, Paixão N, Ferreira LG, Santos FR, Neves LD, Oliveira GC, Cortes VF, Salomé KS, Barison A, Santos FV, Cenzi G, Varotti FP, Oliveira SM, Taranto AG, Comar M, Silva LM, Noël F, Quintas LE, Barbosa LA, Villar JA.
Abstract : Cardiotonic steroids (CS), natural compounds with traditional use in cardiology, have been recently suggested to exert potent anticancer effects. However, the repertoire of molecules with Na,K-ATPase activity and anticancer properties is limited. This paper describes the synthesis of 6 new digoxin derivatives substituted (on the C17-butenolide) with γ-benzylidene group and their cytotoxic effect on human fibroblast (WI-26 VA4) and cancer (HeLa and RKO) cell lines as well as their effect on Na,K-ATPase activity and expression. As digoxin, compound BD-4 was almost 100-fold more potent than the other derivatives for cytotoxicity with the three types of cells used and was also the only one able to fully inhibit the Na,K-ATPase of HeLa cells after 24h treatment. No change in the Na,K-ATPase α1 isoform protein expression was detected. On the other hand it was 30-40 fold less potent for direct Na,K-ATPase inhibition, when compared to the most potent derivatives, BD-1 and BD-3, and digoxin. The data presented here demonstrated that the anticancer effect of digoxin derivatives substituted with γ-benzylidene were not related with their inhibition of Na,K-ATPase activity or alteration of its expression, suggesting that this classical molecular mechanism of CS is not involved in the cytotoxic effect of our derivatives.
|
Inhibition of Wistar rat brain Na(+)/K(+) ATPase alpha-2/3 assessed as amount of Pi release after 1 hr by colorimetric method
|
Rattus norvegicus
|
220.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : γ-Benzylidene digoxin derivatives synthesis and molecular modeling: Evaluation of anticancer and the Na,K-ATPase activity effect.
Year : 2015
Volume : 23
Issue : 15
First Page : 4397
Last Page : 4404
Authors : Alves SL, Paixão N, Ferreira LG, Santos FR, Neves LD, Oliveira GC, Cortes VF, Salomé KS, Barison A, Santos FV, Cenzi G, Varotti FP, Oliveira SM, Taranto AG, Comar M, Silva LM, Noël F, Quintas LE, Barbosa LA, Villar JA.
Abstract : Cardiotonic steroids (CS), natural compounds with traditional use in cardiology, have been recently suggested to exert potent anticancer effects. However, the repertoire of molecules with Na,K-ATPase activity and anticancer properties is limited. This paper describes the synthesis of 6 new digoxin derivatives substituted (on the C17-butenolide) with γ-benzylidene group and their cytotoxic effect on human fibroblast (WI-26 VA4) and cancer (HeLa and RKO) cell lines as well as their effect on Na,K-ATPase activity and expression. As digoxin, compound BD-4 was almost 100-fold more potent than the other derivatives for cytotoxicity with the three types of cells used and was also the only one able to fully inhibit the Na,K-ATPase of HeLa cells after 24h treatment. No change in the Na,K-ATPase α1 isoform protein expression was detected. On the other hand it was 30-40 fold less potent for direct Na,K-ATPase inhibition, when compared to the most potent derivatives, BD-1 and BD-3, and digoxin. The data presented here demonstrated that the anticancer effect of digoxin derivatives substituted with γ-benzylidene were not related with their inhibition of Na,K-ATPase activity or alteration of its expression, suggesting that this classical molecular mechanism of CS is not involved in the cytotoxic effect of our derivatives.
|
Cytotoxicity against human HT-29 cells incubated for 72 hrs by SRB assay
|
Homo sapiens
|
380.0
nM
|
|
Journal : J Nat Prod
Title : Cardiac Glycoside Constituents of Streblus asper with Potential Antineoplastic Activity.
Year : 2017
Volume : 80
Issue : 3
First Page : 648
Last Page : 658
Authors : Ren Y, Chen WL, Lantvit DD, Sass EJ, Shriwas P, Ninh TN, Chai HB, Zhang X, Soejarto DD, Chen X, Lucas DM, Swanson SM, Burdette JE, Kinghorn AD.
Abstract : Three new (1-3) and two known (4 and 5) cytotoxic cardiac glycosides were isolated and characterized from a medicinal plant, Streblus asper Lour. (Moraceae), collected in Vietnam, with six new analogues and one known derivative (5a-g) synthesized from (+)-strebloside (5). A preliminary structure-activity relationship study indicated that the C-10 formyl and C-5 and C-14 hydroxy groups and C-3 sugar unit play important roles in the mediation of the cytotoxicity of (+)-strebloside (5) against HT-29 human colon cancer cells. When evaluated in NCr nu/nu mice implanted intraperitoneally with hollow fibers facilitated with either MDA-MB-231 human breast or OVCAR3 human ovarian cancer cells, (+)-strebloside (5) showed significant cell growth inhibitory activity in both cases, in the dose range 5-30 mg/kg.
|
Cytotoxicity against human MV4-11 cells incubated for 48 hrs by MTS assay
|
Homo sapiens
|
111.0
nM
|
|
Journal : J Nat Prod
Title : Cardiac Glycoside Constituents of Streblus asper with Potential Antineoplastic Activity.
Year : 2017
Volume : 80
Issue : 3
First Page : 648
Last Page : 658
Authors : Ren Y, Chen WL, Lantvit DD, Sass EJ, Shriwas P, Ninh TN, Chai HB, Zhang X, Soejarto DD, Chen X, Lucas DM, Swanson SM, Burdette JE, Kinghorn AD.
Abstract : Three new (1-3) and two known (4 and 5) cytotoxic cardiac glycosides were isolated and characterized from a medicinal plant, Streblus asper Lour. (Moraceae), collected in Vietnam, with six new analogues and one known derivative (5a-g) synthesized from (+)-strebloside (5). A preliminary structure-activity relationship study indicated that the C-10 formyl and C-5 and C-14 hydroxy groups and C-3 sugar unit play important roles in the mediation of the cytotoxicity of (+)-strebloside (5) against HT-29 human colon cancer cells. When evaluated in NCr nu/nu mice implanted intraperitoneally with hollow fibers facilitated with either MDA-MB-231 human breast or OVCAR3 human ovarian cancer cells, (+)-strebloside (5) showed significant cell growth inhibitory activity in both cases, in the dose range 5-30 mg/kg.
|
Cytotoxicity against human Kasumi-1 cells incubated for 48 hrs by MTS assay
|
Homo sapiens
|
93.0
nM
|
|
Journal : J Nat Prod
Title : Cardiac Glycoside Constituents of Streblus asper with Potential Antineoplastic Activity.
Year : 2017
Volume : 80
Issue : 3
First Page : 648
Last Page : 658
Authors : Ren Y, Chen WL, Lantvit DD, Sass EJ, Shriwas P, Ninh TN, Chai HB, Zhang X, Soejarto DD, Chen X, Lucas DM, Swanson SM, Burdette JE, Kinghorn AD.
Abstract : Three new (1-3) and two known (4 and 5) cytotoxic cardiac glycosides were isolated and characterized from a medicinal plant, Streblus asper Lour. (Moraceae), collected in Vietnam, with six new analogues and one known derivative (5a-g) synthesized from (+)-strebloside (5). A preliminary structure-activity relationship study indicated that the C-10 formyl and C-5 and C-14 hydroxy groups and C-3 sugar unit play important roles in the mediation of the cytotoxicity of (+)-strebloside (5) against HT-29 human colon cancer cells. When evaluated in NCr nu/nu mice implanted intraperitoneally with hollow fibers facilitated with either MDA-MB-231 human breast or OVCAR3 human ovarian cancer cells, (+)-strebloside (5) showed significant cell growth inhibitory activity in both cases, in the dose range 5-30 mg/kg.
|
Cytotoxicity against human H1299 cells incubated for 24 hrs by MTT assay
|
Homo sapiens
|
460.0
nM
|
|
Journal : J Nat Prod
Title : Cardiac Glycoside Constituents of Streblus asper with Potential Antineoplastic Activity.
Year : 2017
Volume : 80
Issue : 3
First Page : 648
Last Page : 658
Authors : Ren Y, Chen WL, Lantvit DD, Sass EJ, Shriwas P, Ninh TN, Chai HB, Zhang X, Soejarto DD, Chen X, Lucas DM, Swanson SM, Burdette JE, Kinghorn AD.
Abstract : Three new (1-3) and two known (4 and 5) cytotoxic cardiac glycosides were isolated and characterized from a medicinal plant, Streblus asper Lour. (Moraceae), collected in Vietnam, with six new analogues and one known derivative (5a-g) synthesized from (+)-strebloside (5). A preliminary structure-activity relationship study indicated that the C-10 formyl and C-5 and C-14 hydroxy groups and C-3 sugar unit play important roles in the mediation of the cytotoxicity of (+)-strebloside (5) against HT-29 human colon cancer cells. When evaluated in NCr nu/nu mice implanted intraperitoneally with hollow fibers facilitated with either MDA-MB-231 human breast or OVCAR3 human ovarian cancer cells, (+)-strebloside (5) showed significant cell growth inhibitory activity in both cases, in the dose range 5-30 mg/kg.
|
Inhibition of recombinant rat Na+/K+-ATPase alpha4/beta1 expressed in baculovirus infected insect Sf9 cell membranes using [gamma-32P]ATP as substrate preincubated for 10 mins followed by substrate addition measured after 30 mins in presence of Na+, K+ and Mg2+ by liquid scintillation counting
|
Rattus norvegicus
|
5.5
nM
|
|
Journal : J Med Chem
Title : Design, Synthesis, and in Vitro and in Vivo Evaluation of Ouabain Analogues as Potent and Selective Na,K-ATPase α4 Isoform Inhibitors for Male Contraception.
Year : 2018
Volume : 61
Issue : 5
First Page : 1800
Last Page : 1820
Authors : Syeda SS, Sánchez G, Hong KH, Hawkinson JE, Georg GI, Blanco G.
Abstract : Na,K-ATPase α4 is a testis-specific plasma membrane Na+ and K+ transporter expressed in sperm flagellum. Deletion of Na,K-ATPase α4 in male mice results in complete infertility, making it an attractive target for male contraception. Na,K-ATPase α4 is characterized by a high affinity for the cardiac glycoside ouabain. With the goal of discovering selective inhibitors of the Na,K-ATPase α4 and of sperm function, ouabain derivatives were modified at the glycone (C3) and the lactone (C17) domains. Ouabagenin analogue 25, carrying a benzyltriazole moiety at C17, is a picomolar inhibitor of Na,K-ATPase α4, with an outstanding α4 isoform selectivity profile. Moreover, compound 25 decreased sperm motility in vitro and in vivo and affected sperm membrane potential, intracellular Ca2+, pH, and hypermotility. These results proved that the new ouabagenin triazole analogue is an effective and selective inhibitor of Na,K-ATPase α4 and sperm function.
|
Inhibition of human Na+/K+-ATPase assessed as reduction in inorganic phosphate release from ATP incubated for 15 mins followed by ATP addition measured over 15 mins in presence of Na+/K+ by colorimetric method
|
Homo sapiens
|
270.0
nM
|
|
Journal : Bioorg Med Chem Lett
Title : Synthesis and evaluation of panaxatriol derivatives as Na+, K+-ATPase inhibitors.
Year : 2018
Volume : 28
Issue : 17
First Page : 2885
Last Page : 2889
Authors : Wu Q, Chen P, Tu G, Li M, Pan B, Guo Y, Zhai J, Fu H.
Abstract : Panaxatriol, a triterpene bearing a steroid-like structure similar to cardiac glycosides, was presumed to share the same bioactivity with cardiac glycosides, and may be a potential Na+, K+-ATPase inhibitor. In this paper, a series of panaxatriol derivatives were synthesized and evaluated for Na+, K+-ATPase inhibitory activities. The results of biological tests showed that more than half of the synthesized derivatives presented increased inhibitory activities compared with panaxatriol. Of these compounds, 13a with a 3, 4-seco skeleton showed the most potent inhibitory activity, which was equal to that of the standard drug digoxin. To understand the binding mode of the most active compound, molecular docking study of 13a with Na+, K+-ATPase was conducted. Therefore, 13a may serve as a new lead compound for the development of novel Na+, K+-ATPase inhibitors.
|
Antiviral activity against SARS-CoV-2 (viral titer) measured by plaque assay in Vero cells at MOI 0.0125 after 24 hr
|
Chlorocebus sabaeus
|
190.0
nM
|
|
Title : Identification of antiviral drug candidates against SARS-CoV-2 from FDA-approved drugs
Year : 2020
Authors : Sangeun Jeon, Meehyun Ko, Jihye Lee, Inhee Choi, Soo Young Byun, Soonju Park, David Shum, Seungtaek Kim
Abstract : COVID-19 is an emerging infectious disease and was recently declared as a pandemic by WHO. Currently, there is no vaccine or therapeutic available for this disease. Drug repositioning represents the only feasible option to address this global challenge and a panel of 48 FDA- approved drugs that have been pre-selected by an assay of SARS-CoV was screened to identify potential antiviral drug candidates against SARS-CoV-2 infection. We found a total of 24 drugs which exhibited antiviral efficacy (0.1 μM < IC50 < 10 μM) against SARS-CoV-2. In particular, two FDA-approved drugs - niclosamide and ciclesonide – were notable in some respects. These drugs will be tested in an appropriate animal model for their antiviral activities. In near future, these already FDA-approved drugs could be further developed following clinical trials in order to provide additional therapeutic options for patients with COVID-19.
|
SARS-CoV-2 3CL-Pro protease inhibition percentage at 20µM by FRET kind of response from peptide substrate
|
Severe acute respiratory syndrome coronavirus 2
|
18.32
%
|
|
Title : Identification of inhibitors of SARS-Cov2 M-Pro enzymatic activity using a small molecule repurposing screen
Year : 2020
Authors : Maria Kuzikov, Elisa Costanzi, Jeanette Reinshagen, Francesca Esposito, Laura Vangeel, Markus Wolf, Bernhard Ellinger, Carsten Claussen, Gerd Geisslinger, Angela Corona, Daniela Iaconis, Carmine Talarico, Candida Manelfi, Rolando Cannalire, Giulia Rossetti, Jonas Gossen, Simone Albani, Francesco Musiani, Katja Herzog, Yang Ye, Barbara Giabbai, Nicola Demitri, Dirk Jochmans, Steven De Jonghe, Jasper Rymenants, Vincenzo Summa, Enzo Tramontano, Andrea R. Beccari, Pieter Leyssen, Paola Storici, Johan Neyts, Philip Gribbon, and Andrea Zaliani
Abstract : Compound repurposing is an important strategy being pursued in the identification of effective treatment against the SARS-CoV-2 infection and COVID-19 disease. In this regard, SARS-CoV-2 main protease (M-Pro), also termed 3CL-Pro, is an attractive drug target as it plays a central role in viral replication by processing the viral polyprotein into 11 non-structural proteins. We report the results of a screening campaign involving ca 8.7 K compounds containing marketed drugs, clinical and preclinical candidates, and chemicals regarded as safe in humans. We confirmed previously reported inhibitors of 3CL-Pro, but we have also identified 68 compounds with IC50 lower than 1 uM and 127 compounds with IC50 lower than 5 uM. Profiling showed 67% of confirmed hits were selective (> 5 fold) against other Cys- and Ser- proteases (Chymotrypsin and Cathepsin-L) and MERS 3CL-Pro. Selected compounds were also analysed in their binding characteristics.
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
-0.38
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
-0.38
%
|
|
Title : Cytopathic SARS-Cov2 screening on VERO-E6 cells in a large repurposing effort
Year : 2020
Authors : Andrea Zaliani, Laura Vangeel, Jeanette Reinshagen, Daniela Iaconis, Maria Kuzikov, Oliver Keminer, Markus Wolf, Bernhard Ellinger, Francesca Esposito, Angela Corona, Enzo Tramontano, Candida Manelfi, Katja Herzog, Dirk Jochmans, Steven De Jonghe, Winston Chiu, Thibault Francken, Joost Schepers, Caroline Collard, Kayvan Abbasi, Carsten Claussen , Vincenzo Summa, Andrea R. Beccari, Johan Neyts, Philip Gribbon and Pieter Leyssen
Abstract : Worldwide, there are intensive efforts to identify repurposed drugs as potential therapies against SARS-CoV-2 infection and the associated COVID-19 disease. To date, the anti-inflammatory drug dexamethasone and (to a lesser extent) the RNA-polymerase inhibitor remdesivir have been shown to be effective in reducing mortality and patient time to recovery, respectively, in patients. Here, we report the results of a phenotypic screening campaign within an EU-funded project (H2020-EXSCALATE4COV) aimed at extending the repertoire of anti-COVID therapeutics through repurposing of available compounds and highlighting compounds with new mechanisms of action against viral infection. We screened 8702 molecules from different repurposing libraries, to reveal 110 compounds with an anti-cytopathic IC50 < 20 µM. From this group, 18 with a safety index greater than 2 are also marketed drugs, making them suitable for further study as potential therapies against COVID-19. Our result supports the idea that a systematic approach to repurposing is a valid strategy to accelerate the necessary drug discovery process.
|
Cytotoxicity against human HT-29 cells after 72 hrs by CellTiter 96 Aqueous One Solution reagent based assay
|
Homo sapiens
|
280.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Cytotoxicity against human MDA-MB-231 cells after 72 hrs by CellTiter 96 Aqueous One Solution reagent based assay
|
Homo sapiens
|
310.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Cytotoxicity against human OVCAR3 cells after 72 hrs by CellTiter 96 Aqueous One Solution reagent based assay
|
Homo sapiens
|
100.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Cytotoxicity against human MDA-MB-435 cells after 72 hrs by CellTiter 96 Aqueous One Solution reagent based assay
|
Homo sapiens
|
170.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Inhibition of porcine cortex Na+/K+-ATPase using ATP as substrate after 15 mins by ADP-Glo Reagent based method
|
Sus scrofa
|
230.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Cytotoxicity against human NCI-H1299 cells after 24 hrs by MTT assay
|
Homo sapiens
|
460.0
nM
|
|
Journal : J Nat Prod
Title : Na<sup>+</sup>/K<sup>+</sup>-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.
Year : 2020
Volume : 83
Issue : 3
First Page : 638
Last Page : 648
Authors : Ren Y, Ribas HT, Heath K, Wu S, Ren J, Shriwas P, Chen X, Johnson ME, Cheng X, Burdette JE, Kinghorn AD.
Abstract : (+)-Digoxin (<b>1</b>) is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (<b>2</b>-<b>5</b>) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin (<b>6</b>) and (+)-17-<i>epi</i>-20,22-dihydro-21α-hydroxydigoxin (<b>7</b>), were synthesized from <b>1</b> and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for <b>1</b> to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic <b>1</b> and the noncytotoxic derivative <b>7</b> bind differentially to Na<sup>+</sup>/K<sup>+</sup>-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin (<b>1</b>) may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na<sup>+</sup>/K<sup>+</sup>-ATPase, respectively, but the altered lactone unit of <b>7</b> results in a rotation of its steroid core, which depotentiates the binding between this compound and Na<sup>+</sup>/K<sup>+</sup>-ATPase. Thus, <b>1</b> was found to inhibit Na<sup>+</sup>/K<sup>+</sup>-ATPase, but <b>7</b> did not. In addition, the cytotoxic <b>1</b> did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na<sup>+</sup>/K<sup>+</sup>-ATPase but not by interacting with glucose transporters.
|
Cytotoxicity against human BT-549 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
51.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human Hs-578T cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
69.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human CAL-51 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
130.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human MDA-MB-468 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
230.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human MDA-MB-453 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
230.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human SUM185PE cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
280.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human HCC1806 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
280.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human MDA-MB-231 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
480.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human HCC1937 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
550.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
|
Cytotoxicity against human HCC70 cells assessed as reduction in cell viability after 48 hrs by SRB assay
|
Homo sapiens
|
640.0
nM
|
|
Journal : J Nat Prod
Title : Triple-Negative Breast Cancer Cells Exhibit Differential Sensitivity to Cardenolides from Calotropis gigantea.
Year : 2020
Volume : 83
Issue : 7.0
First Page : 2269
Last Page : 2280
Authors : Pederson PJ,Cai S,Carver C,Powell DR,Risinger AL,Grkovic T,O'Keefe BR,Mooberry SL,Cichewicz RH
Abstract : Triple-negative breast cancers (TNBC) are aggressive and heterogeneous cancers that lack targeted therapies. We implemented a screening program to identify new leads for subgroups of TNBC using diverse cell lines with different molecular drivers. Through this program, we identified an extract from Calotropis gigantea that caused selective cytotoxicity in BT-549 cells as compared to four other TNBC cell lines. Bioassay-guided fractionation of the BT-549 selective extract yielded nine cardenolides responsible for the selective activity. These included eight known cardenolides and a new cardenolide glycoside. Structure-activity relationships among the cardenolides demonstrated a correlation between their relative potencies toward BT-549 cells and Na/K ATPase inhibition. Calotropin, the compound with the highest degree of selectivity for BT-549 cells, increased intracellular Ca in sensitive cells to a greater extent than in the resistant MDA-MB-231 cells. Further studies identified a second TNBC cell line, Hs578T, that is also highly sensitive to the cardenolides, and mechanistic studies were conducted to identify commonalities among the sensitive cell lines. Experiments showed that both cardenolide-sensitive cell lines expressed higher mRNA levels of the Na/Ca exchanger NCX1 than resistant TNBC cells. This suggests that NCX1 could be a biomarker to identify TNBC patients that might benefit from the clinical administration of a cardiac glycoside for anticancer indications.
