Biochemical characterisation of elsamicin and other coumarin-related antitumour agents as potent inhibitors of human topoisomerase II.
Elsamicin (EM) is a recently discovered antitumour agent that is structurally related to several other compounds displaying anticancer activities, including chartreusin (CT), chrysomycin V (CV) and M (CM), gilvocarcin V (GV) and ravidomycin (RM). The biochemical events resulting in cytotoxicity for most of these compounds have not been clearly elucidated. There is some evidence that GV and CT bind to DNA and that GV is photosensitive, causing DNA damage. Therefore, we investigated the effects of these chemicals on DNA in cells and on pBR322 plasmid DNA. Using alkaline elution techniques, we found that all these compounds induced, to a different extent, DNA breakage in the human lung adenocarcinoma A549 cell line. In addition, all either bound to or intercalated into DNA, as indicated by their ability to alter the electrophoretic migration of DNA in agarose gels. Using the P4 unknotting assay, EM, CT, CV, CM, GV and RM were found to be potent inhibitors of the catalytic activity of topoisomerase II (topo II). Their potencies were compared with the known topo II inhibitors teniposide (VM-26) and doxorubicin (DX). EM was the most potent, with an IC50 of 0.4 mumol/l followed in order by CV, GV, and CT. VM-26 was the least potent with an IC50 of 15 mumol/l. It was concluded from these results that EM, GV, CV, CM and CT are capable of inhibiting topo II and that EM is the most potent inhibitor of topo II yet discovered.
Lorico
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A
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510-8066.
Long
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BH
D000230:Adenocarcinoma / Q000188:drug therapy; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001578:Benzopyrans / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D003374:Coumarins / Q000494:pharmacology; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000187:drug effects; D006027:Glycosides / Q000494:pharmacology; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D001578:Benzopyrans; D003374:Coumarins; D004273:DNA, Neoplasm; D006027:Glycosides; D059005:Topoisomerase II Inhibitors; C031781:gilvocarcin V; C002185:chartreusin; C049904:elsamicin A