title: Transcriptional inhibition of p21WAF1/CIP1 gene (CDKN1) expression by survivin is at least partially p53-dependent: evidence for survivin acting as a transcription factor or co-factor.
abstract: Growing evidence suggests a role for the antiapoptotic protein survivin in promotion of cancer cell G1/S transition and proliferation. However, the underlying mechanism is unclear. Further, although upregulation of p21(WAF1/CIP1) by p53 plays an important role in p53-mediated cell G1 arrests in response to various distresses, it is unknown whether survivin plays a role in the regulation of p21(WAF1/CIP1) expression. Here, we report that exogenous expression of survivin in p53-wild type MCF-7 breast cancer cells inhibits the expression of p21(WAF1/CIP1) protein, mRNA and promoter activity, while the survivin C84A mutant and antisense failed to do so. Cotransfection experiments in the p53 mutant H1650 lung cancer cell line showed that survivin neutralizes p53-induced p21(WAF1/CIP1) expression and promoter activity. Importantly, genetically silencing of endogenous survivin using lentiviral survivin shRNA also enhances endogenous p21 in p53 wild type cancer cells, suggesting the physiological relevance of the fining. We further demonstrated that both p53 and survivin interacts on the two p53-binding sites in the p21(WAF1/CIP1) promoter (-2313 to -2212; -1452 to -1310), and survivin physically interacts with p53 in cancer cells. Together, we propose that survivin may act as a transcription factor or cofactor to interact with p53 on the p21(WAF1/CIP1) promoter leading to the inhibition of p21(WAF1/CIP1) expression at least in part by neutralizing p53-mediated transcriptional activation of the p21 gene.
authors.affiliation: Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA and.|Pre-doctoral Chinese fellowship student, Second West China Hospital, Sichuan University, Sichuan, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA and.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ling
authors.affiliation: Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA and.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA and.
authors.forename: Gokul M
authors.initials: GM
authors.lastname: Das
authors.affiliation: Department of Pharmacology & Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA and.
authors.forename: Fengzhi
authors.initials: F
authors.lastname: Li
mesh_terms: D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000037:antagonists & inhibitors / Q000235:genetics*; D016193:G1 Phase / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D016196:S Phase / Q000235:genetics; D000077022:Survivin; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: C107489:BIRC5 protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D051034:Inhibitor of Apoptosis Proteins; D012333:RNA, Messenger; D000077022:Survivin; D016159:Tumor Suppressor Protein p53