期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1986
卷号:83
期号:11
页码:3847-3850
DOI:10.1073/pnas.83.11.3847
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:Multiple drug resistance of tumor cells is a common problem in cancer therapy. We have demonstrated that membrane vesicles from highly multidrug-resistant human KB carcinoma cell lines exhibit increased specific and saturable binding of vinblastine. To identify the molecules that bind vinblastine, membrane vesicles from multidrug-resistant cells were exposed to two analogs of vinblastine, N-(p-azido-[3,5-3H]benzoyl)-N'-(beta-aminoethyl)vindesine and N-(p-azido-[3-125I]salicyl)-N'-(beta-aminoethyl)vindesine, that could be photoactivated. Our studies show the specific labeling of a 150- to 170-kDa protein in membrane vesicles from two independently selected multidrug-resistant KB cell lines, which was not seen in drug-sensitive parental or revertant cell lines. The labeling of the high molecular weight protein was inhibited in a dose-dependent manner by vinblastine with half-maximal inhibition at about 1 microM. Photolabeling was also inhibited by 100 microM vincristine or 100 microM verapamil but not by 100 microM colchicine or 100 microM dexamethasone. The data suggest that the 150- to 170-kDa protein may play an important role in the multidrug-resistance phenotype.