Rab6c, a new member of the Rab gene family, is involved in drug resistancein MCF7/AdrR cells

A new Rab6 homolog cDNA, Rab6c, was discovered by a hypermethylated DNA fra gment probe that was isolated from a human multidrug resistant (MDR) breast cancer cell line, MCF7/AdrR, by the methylation sensitive-representational difference analysis (MS-RDA) technique. Rab6c was found to be under-expres sed in MCF7/AdrR and MES-SA/Dx5 (a human MDR uterine sarcoma cell line) com pared with their non-MDR parental cell lines. MCF7/AdrR cells expressing th e exogenous Rab6c exhibited less resistance to several anti-cancer drugs, s uch as doxorubicin (DOX), taxol, vinblastine, and vincristine, than the con trol cells containing the empty vector. Flow cytometry experiments confirme d that the transfectants' diminished resistance to DOX was caused by increa sed drug accumulation induced by the exogenous Rab6c. These results indicat e that Rab6c is involved in drug resistance in MCF7/AdrR cells. (C) 2000 El sevier Science B.V. All rights reserved.