Characterization of an unusual mutant of human melanoma cells resistant to anticancer drugs that inhibit topoisomerase II

J. A. Campain, R. Padmanabhan, J. Hwang, M. M. Gottesman, I. Pastan

研究成果: 雜誌貢獻文章同行評審

15 引文 斯高帕斯(Scopus)


The topoisomerase II inhibitor, VP-16 (etoposide), is an important component in many chemotherapeutic regimens. To characterize resistance to this drug, the human melanoma cell line, FEM-X, was selected in multiple steps with VP-16. To prevent the development of typical multidrug resistance, an inhibitor of P-glycoprotein, the tiapamil analog, RO-11-2933, was added to the selections. The resultant clone FVP3 is 56-fold resistant to VP-16 and cross-resistant to doxorubicin (Adriamycin) (9-fold) and VM-26 (27-fold). These cells are also two- to fourfold resistant to m-AMSA, daunorubicin, and mitoxantrone. FVP3 is not resistant to the P-glycoprotein substrate vinblastine, does not express the MDR1 gene at detectable levels, and does not show reduced 3H-VP-16 accumulation. Unlike other cell lines that exhibit resistance to inhibitors of topoisomerase II, FVP3 has the same level of topoisomerase II expression and activity as FEM-X. Using live cells treated with VP-16, band depletion assays and KCl/SDS precipitation assays show that topoisomerase II from FVP3 is much less susceptible to drug-induced cleavable complex formation than is that from FEM-X. This difference in sensitivity to VP-16 is also detected using lysates from disrupted cells, but not with isolated nuclei devoid of cytoplasmic and membrane components. In addition, the topoisomerase II present in nuclear extracts from FVP3 is not resistant to the effects of VP-16 as measured by: (1) inhibition of strand passing activity during decatenation of kinetoplast DNA, (2) drug-induced linearization of plasmid DNA, and (3) immunodepletion by VP-16. These results suggest that some component of the cytoplasm or cellular membranes, or a factor depleted from nuclei during their isolation, is responsible for the resistance to VP-16 in FVP3.

頁(從 - 到)414-425
期刊Journal of Cellular Physiology
出版狀態已發佈 - 1993

ASJC Scopus subject areas

  • 細胞生物學
  • 臨床生物化學
  • 生理學


深入研究「Characterization of an unusual mutant of human melanoma cells resistant to anticancer drugs that inhibit topoisomerase II」主題。共同形成了獨特的指紋。