title: Unique induction of p21(WAF1/CIP1)expression by vinorelbine in androgen-independent prostate cancer cells.
abstract: To study the mechanisms of the development of hormone refractory prostate cancer, we established an androgen-independent (AI) prostate cancer cell line derived from hormone-dependent (AD) LNCaP cells. Our previous studies have demonstrated that AI cells are deficient in expression of p21(WAFl/CIP1) (p21) due to overexpressed AR and are resistant to apoptosis. In this study, the induction of p53 and p21 expression by vinorelbine (Navelbine) was compared between AD and AI cells in an attempt to understand the difference(s) in apoptotic signalling pathways in these cells. Using a series of deletion of p21 reporter constructs, we found that vinorelbine mediated p21 induction in a p53-dependent manner in AD cells. In contrast, p21 expression restored by vinorelbine in AI cells was found to be through both p53-dependent and-independent pathways. In the absence of two p53 binding sites, Spl-3 and Spl-4 sites, in the promoter of human p21 gene, were found to be required for vinorelbine-mediated p21 activation. No p21 induction was observed by paclitaxel in AI cells. Exposure of AI cells to paciltaxel followed by vinorelbine produced synergism. Our data, thus, provide a basis for the synergistic combination of vinorelbine and paclitaxel for the treatment of advanced prostate cancer.
authors.affiliation: Department of Medicine, Division of Medical Oncology, Mount Sinai School of Medicine, One Gustave L Levy Place, Box 1129, New York, NY 10029, USA.
authors.forename: X M
authors.initials: XM
authors.lastname: Liu
authors.forename: J D
authors.initials: JD
authors.lastname: Jiang
authors.forename: A C
authors.initials: AC
authors.lastname: Ferrari
authors.forename: D R
authors.initials: DR
authors.lastname: Budman
authors.forename: L G
authors.initials: LG
authors.lastname: Wang
mesh_terms: D000726:Androgen Antagonists / Q000494:pharmacology*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis* / Q000494:pharmacology; D004347:Drug Interactions; D019008:Drug Resistance, Neoplasm; D004359:Drug Therapy, Combination; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D008297:Male; D017239:Paclitaxel / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D014407:Tumor Cells, Cultured; D014747:Vinblastine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000077235:Vinorelbine
chemical_list: D000726:Androgen Antagonists; D000972:Antineoplastic Agents, Phytogenic; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D014747:Vinblastine; D017239:Paclitaxel; D000077235:Vinorelbine