title: Benzoquinonoid ansamycins possess selective tumoricidal activity unrelated to src kinase inhibition.
abstract: The benzoquinonoid ansamycin antibiotics herbimycin A and geldanamycin have been shown to reverse the oncogenic phenotype of pp60v-src transformed cells as well as induce differentiation in a number of in vitro model systems, reportedly due to their inhibition of src family protein tyrosine kinases. We now report that these agents are potent cytotoxins in vitro against a panel of highly malignant human tumor cell lines possessing primitive neural features. Proliferation and/or survival of fibroblasts, primary neuronal cultures, and several leukemia cell lines are unaffected at concentrations resulting in greater than 99% cell loss in sensitive lines. The tumorigenicity in nude mice of sensitive cell lines can also be markedly reduced by either systemic or topical administration of these agents without apparent toxicity to the whole animal. The cytocidal action of these ansamycins is initiated very rapidly, is irreversible, and is clearly distinct from the delayed inhibition of src family kinases that has been reported previously. Due to their potency, relative selectivity, and novel mechanism(s) of action, these drugs could prove clinically useful in the therapy of a number of human cancers of neural derivation.
authors.affiliation: Tumor Cell Biology Section, National Cancer Institute, NIH, Bethesda, Maryland 20892.
authors.forename: L
authors.initials: L
authors.lastname: Whitesell
authors.forename: S D
authors.initials: SD
authors.lastname: Shifrin
authors.forename: G
authors.initials: G
authors.lastname: Schwab
authors.forename: L M
authors.initials: LM
authors.lastname: Neckers
mesh_terms: D016475:3T3 Cells; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D016227:Benzoquinones; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007700:Kinetics; D047029:Lactams, Macrocyclic; D051379:Mice; D015688:Oncogene Protein pp60(v-src) / Q000037:antagonists & inhibitors* / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011809:Quinones / Q000494:pharmacology*; D017828:Rifabutin / Q000031:analogs & derivatives; D014162:Transfection
chemical_list: D000903:Antibiotics, Antineoplastic; D016227:Benzoquinones; D047029:Lactams, Macrocyclic; D011809:Quinones; D017828:Rifabutin; C020754:herbimycin; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); C001277:geldanamycin