title: Cellular mechanisms of multidrug resistance of tumor cells.
abstract: Multidrug resistance (MDR) is the protection of a tumor cell population against numerous drugs differing in chemical structure and mechanisms of influence on the cells. MDR is one of the major causes of failures of chemotherapy of human malignancies. Recent studies show that the molecular mechanisms of MDR are numerous. Cellular drug resistance is mediated by different mechanisms operating at different steps of the cytotoxic action of the drug from a decrease of drug accumulation in the cell to the abrogation of apoptosis induced by the chemical substance. Often several different mechanisms are switched on in the cells, but usually one major mechanism is operating. The most investigated mechanisms with known clinical significance are: a) activation of transmembrane proteins effluxing different chemical substances from the cells (P-glycoprotein is the most known efflux pump); b) activation of the enzymes of the glutathione detoxification system; c) alterations of the genes and the proteins involved into the control of apoptosis (especially p53 and Bcl-2).
authors.affiliation: Institute of Carcinogenesis, Blokhin Russian Cancer Research Center, Russian Academy of Medical Sciences, Moscow, 115478, Russia. Alla@Astavrovskaya.home.bio.msu.ru
authors.forename: A A
authors.initials: AA
authors.lastname: Stavrovskaya
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D017209:Apoptosis; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D009369:Neoplasms / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D005982:Glutathione Transferase