title: Acquisition of drug resistance by constitutive suppression of NF-kappaB in ras-transformed NIH3T3 mouse fibroblasts.
abstract: Apoptotic cell death is frequently suppressed by NF-kappaB transcription factor. We examined the effects of NF-kappaB on the sensitivity to anti-cancer drugs by using two NF-kappaB-inhibitory molecules, IkappaBalpha-super-repressor (IkappaBalpha-SR) and dominant negative IKKbeta (IKKbeta-DN). Ha-ras-transformed NIH3T3 (ras-NIH3T3) mouse fibroblasts were stably transfected with these cDNAs, and suppression of NF-kappaB activity was confirmed by electrophoretic mobility shift assays. Cell viability analysis revealed that IkappaBalpha-SR- or IKKbeta-DN-transfected cells were more resistant to peplomycin, mitomycin C, and camptothecin. Flow cytometric analysis indicated partial G1 arrest of these transfected cells. Consistently, elevated expression of IkappaBalpha-SR and IKKbeta-DN was accompanied by increased levels of p21 but not of Bax. Transfection of p21 into ras-NIH3T3 cells caused similar reduced chemosensitivity to the anti-cancer drugs. These results collectively indicate that constitutive suppression of NF-kappaB activity reduced the chemosensitivity to anti-cancer drugs via enhanced expression of p21.
authors.affiliation: Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sakaida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Iwadate
authors.forename: Sachi
authors.initials: S
authors.lastname: Yamaji
authors.forename: Masae
authors.initials: M
authors.lastname: Uehara
authors.forename: Asao
authors.initials: A
authors.lastname: Noda
authors.forename: Masaki
authors.initials: M
authors.lastname: Takiguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Yamaura
authors.forename: Takaki
authors.initials: T
authors.lastname: Hiwasa
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D015153:Blotting, Western; D002166:Camptothecin / Q000494:pharmacology; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D004396:Coloring Agents / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D051379:Mice; D016685:Mitomycin / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D041681:NIH 3T3 Cells; D017663:Peplomycin / Q000494:pharmacology; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D014162:Transfection
chemical_list: D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D004396:Coloring Agents; D016328:NF-kappa B; D013778:Tetrazolium Salts; D013844:Thiazoles; D016685:Mitomycin; D017663:Peplomycin; D004247:DNA; C022616:thiazolyl blue; D002166:Camptothecin