title: alpha(v)beta(3) Integrin-mediated drug resistance in human laryngeal carcinoma cells is caused by glutathione-dependent elimination of drug-induced reactive oxidative species.
abstract: As a model for determination of the role of integrins in drug resistance, we used alpha(v)beta(3) integrin-negative human laryngeal carcinoma cell line (HEp2) and three HEp2-derived cell clones with a gradual increase of alpha(v)beta(3) integrin expression. The alpha(v)beta(3) integrin expression protects cells from cisplatin, mitomycin C, and doxorubicin. In HEp2-alpha(v)beta(3) integrin-expressing cells, the constitutive expression of Bcl-2 protein and the level of glutathione (GSH) were increased compared with HEp2 cells. Pretreatment of HEp2-alpha(v)beta(3) integrin-expressing cells with an inhibitor of GSH synthesis, buthionine sulfoximine (BSO), decreased the level of GSH and partially reverted drug resistance to all above-mentioned drugs, but it did not influence the expression of Bcl-2. Sensitivity to selected anticancer drugs did not change with overexpression of Bcl-2 in HEp2 cells, nor with silencing of Bcl-2 in HEp2-alpha(v)beta(3) integrin-expressing cells, indicating that Bcl-2 is not involved in resistance mechanism. There was no difference in DNA platination between HEp2 and HEp2-alpha(v)beta(3) integrin-expressing cells, indicating that the mechanism of drug resistance is independent of cisplatin detoxification by GSH. A strong increase of reactive oxidative species (ROS) formation during cisplatin or doxorubicin treatment in HEp2 cells was reduced in HEp2-alpha(v)beta(3) integrin-expressing cells. Since this increased elimination of ROS could be reverted by GSH depletion, we concluded that multidrug resistance is the consequence of GSH-dependent increased ability of alpha(v)beta(3)-expressing cells to eliminate drug-induced ROS.
authors.affiliation: Division of Molecular Biology, Ruder Bosković Institute, Bijenicka 54, 10000 Zagreb, Croatia.
authors.forename: Anamaria
authors.initials: A
authors.lastname: Brozovic
authors.forename: Dragomira
authors.initials: D
authors.lastname: Majhen
authors.forename: Vibor
authors.initials: V
authors.lastname: Roje
authors.forename: Nevenka
authors.initials: N
authors.lastname: Mikac
authors.forename: Sanjica
authors.initials: S
authors.lastname: Jakopec
authors.forename: Gerhard
authors.initials: G
authors.lastname: Fritz
authors.forename: Maja
authors.initials: M
authors.lastname: Osmak
authors.forename: Andreja
authors.initials: A
authors.lastname: Ambriovic-Ristov
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D002999:Clone Cells; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005562:Formazans / Q000378:metabolism; D005978:Glutathione / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D007822:Laryngeal Neoplasms / Q000473:pathology; D016685:Mitomycin / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D005562:Formazans; D039302:Integrin alphaVbeta3; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; C079782:MTT formazan; D019328:Buthionine Sulfoximine; D016685:Mitomycin; D004317:Doxorubicin; D005978:Glutathione; D002945:Cisplatin