Abstract 2983: Nkx3.1 and c-Myc co-regulate shared target genes involved in prostate cancer

Cooperativity between oncogenic mutations is recognized as a fundamental feature of malignant transformation, and may be mediated by synergistic regulation of the expression of pro- and anti-tumorigenic target genes. However, the mechanisms by which oncogenic mutations cooperatively regulate downstream target gene expression remain largely unknown. Here we used chromatin immunoprecipitation coupled with massively parallel sequencing (ChIP-seq) and gene expression analyses to identify direct targets of the prostate tumor suppressor Nkx3.1 in the mouse prostate. Our analysis showed that a significant fraction of Nkx3.1 targets are also targets of the oncoprotein c-Myc, suggesting that these two proteins may cooperate in prostate tumorigenesis by directly co-regulating a common set of target genes. Using ChIP, we confirmed binding of Nkx3.1 and c-Myc to the regulatory regions of shared target genes in mouse and human prostate epithelial cells. In conditional mutant mice, loss of Nkx3.1 cooperates with concurrent overexpression of c-MYC to promote prostate tumorigenesis. Furthermore, dysregulation of the shared NKX3.1/c-MYC target gene set was associated with relapse in human prostate tumors. We propose that co-regulation of target gene expression by oncogenic/tumor suppressor transcription factors may represent a general mechanism for the cooperativity of oncogenic mutations during tumorigenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2983. doi:1538-7445.AM2012-2983