Transcriptional repression of Aurora-A gene by wild-type p53 through directly binding to its promoter with histone deacetylase 1 and mSin3a.

In this study, we firstly showed that p53 transcriptionally represses Aurora-A gene expression through directly binding to its promoter. DNA affinity precipitation assay and chromatin immunoprecipitation assay indicated that p53 physically bound to the Aurora-A promoter. Moreover, the in vitro and in vivo assays showed that p53 directly bound to the Aurora-A promoter together with histone deacetylase 1 (HDAC1) and mSin3a as corepressors. Furthermore, we identified that the nucleotides -360 to -354 (CCTGCCC), upstream of the Aurora-A transcriptional start site, was responsible for the p53-mediated repression. Mutation within this site disrupted its interaction with p53, mSin3a and HDAC1, as well as attenuated the repressive effect of p53 on Aurora-A promoter activity. Treatment with trichostatin A (TSA), a HDAC1 inhibitor, disrupted the interaction of p53-HDAC1-mSin3a complex with the nucleotides -365∼-345 region, and enhanced the Aurora-A promoter activity and gene expression. Additionally, knockdown of p53 or mSin3a also drastically blocked the formation of p53-HDAC1-mSin3a repressive complex onto this promoter region and elevated the Aurora-A promoter activity and gene expression. Moreover, the p53-HDAC1-mSin3a repressive complex also involved in the inhibition of Aurora-A gene expression upon cisplatin treatment. Finally, the clinical investigation showed that Aurora-A and p53 exhibited an inverse correlation in both the expression level and prognostic status, and the low p53/high Aurora-A showed the poorest prognosis of NSCLC patients. Our findings showed novel regulatory mechanisms of p53 in regulating Aurora-A gene expression in NSCLC cells.