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.
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Authors | Miguel López-Lázaro, Nuria Pastor, Sami S Azrak, María Jesús Ayuso, Caroline A Austin, Felipe Cortés |
Journal | Journal of natural products
(J Nat Prod)
Vol. 68
Issue 11
Pg. 1642-5
(Nov 2005)
ISSN: 0163-3864 [Print] United States |
PMID | 16309315
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Antineoplastic Agents
- Cardiotonic Agents
- Digitoxin
- DNA Topoisomerases, Type II
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Topics |
- Antineoplastic Agents
(pharmacology)
- Cardiotonic Agents
(pharmacology)
- DNA Damage
- DNA Topoisomerases, Type II
(metabolism)
- Digitoxin
(pharmacology)
- Dose-Response Relationship, Drug
- Humans
- Inhibitory Concentration 50
- Molecular Structure
- Tumor Cells, Cultured
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