title: P21 response to DNA damage induced by genistein and etoposide in human lung cancer cells.
abstract: The p21(WAF1/Cip1) gene plays a central role in cell cycle regulation. Here we show that topoisomerase II inhibitors, genistein and etoposide, induce p21(WAF1/Cip1) expression mainly in a p53-dependent manner in human lung cancer cell line A549. However, although p53 accumulated, p21(WAF1/Cip1) expression did not depend on the level of Ser15 phosphorylation of p53. Caffeine, an ataxia telangiectasia-mutated (ATM), and ATM- and Rad3-related kinase (ATR) inhibitor, abrogated genistein-induced p21(WAF1/Cip1) and largely blocked etoposide-induced p21(WAF1/Cip1) expression. Wortmannin, an ATM- and DNA-dependent protein kinase inhibitor, partially inhibited p21(WAF1/Cip1) expression induced by genistein and etoposide, whereas UCN-01, a Chk1 inhibitor, partially blocked etoposide, but not genistein-induced p21(WAF1/Cip1) expression. These data suggest that both genistein and etoposide induce p21(WAF1/Cip1) expression in a p53-dependent manner. Genistein appears to stimulate p21(WAF1/Cip1) expression through p53 via ATM, whereas etoposide may activate both ATM and ATR pathways. Our results suggest different mechanisms participate in genistein and etoposide induced p21(WAF1/Cip1) expression.
authors.affiliation: Arthur James Cancer Hospital and Richard Solove Research Institute, Comprehensive Cancer Center, and Department of Internal Medicine, The Ohio State University, Columbus, OH 43210-1240, USA.
authors.forename: Haiming
authors.initials: H
authors.lastname: Ding
authors.forename: Wenrui
authors.initials: W
authors.lastname: Duan
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Zhu
authors.forename: Rong
authors.initials: R
authors.lastname: Ju
authors.forename: Kanur
authors.initials: K
authors.lastname: Srinivasan
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Otterson
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Villalona-Calero
mesh_terms: D000970:Antineoplastic Agents / Q000633:toxicity*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors; D002455:Cell Division / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis*; D004249:DNA Damage; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000633:toxicity; D005047:Etoposide / Q000633:toxicity*; D019833:Genistein / Q000633:toxicity*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D012694:Serine / Q000378:metabolism; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D059005:Topoisomerase II Inhibitors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D012694:Serine; D005047:Etoposide; D019833:Genistein; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases