Mr 85,000 membrane protein specifically expressed in adriamycin-resistant human tumor cells

Hirofumi Hamada, Etsuko Okochi, Masahiko Watanabe, Tomoko Oh-hara, Yoshikazu Sugimoto, Hironori Kawabata, Takashi Tsuruo

研究成果: Article査読

30 被引用数 (Scopus)


For the characterization of membrane changes related to Adriamycin resistance in tumor cells, we have developed monoclonal antibodies against Adriamycin-resistant human myelogenous leukemia K562 (K562/ ADM). In addition to the monoclonal antibodies which recognize P-glycoprotein, we have obtained two monoclonal antibodies (designated MRK4 and MRK20) which recognize an Mr, 85,000 membrane protein. Using MRK20 as a probe, we have studied the expression of the Mr 85,000 protein in various human multidrug-resistant and -sensitive cell lines. The Mr 85,000 protein was overexpressed in K562/ADM and in a human ovarian cancer cell line resistant to Adriamycin, 2780AD. The protein, if any, was not detected in other drug-resistant human cell lines such as colchicine-resistant KB cells (KB-C4), vinblastine-resistant CEM cells (cem/vlb100),and vincristine-resistant K562 cells (K562/VCR). We have isolated subclones of K562/ADM cells which express different amounts of the Mr 85,000 protein. The expression of the M, 85,000 protein diminished when the cells were not kept in Adriamycin, and increased when the clones were kept in the presence of Adriamycin. In contrast, the expression of P-glycoprotein remained constant whether in the presence or absence of Adriamycin during these experiments. These findings suggest that the Mr85,000 membrane protein is closely related to the resistant mechanism specific to Adriamycin resistance, which is different from that of the pleiotropic drug resistance.

ジャーナルCancer Research
出版ステータスPublished - 1988 12月 1

ASJC Scopus subject areas

  • 腫瘍学
  • 癌研究


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