Abstract 2888: Identification of an NKX3.1-G9a-UTY regulatory network that controls proper prostate differentiation

Abstract

Abstract Maintenance of cell differentiation is tightly coordinated by specific gene expression programs, which are often deregulated during tumorigenesis. While the homeodomain-containing transcription factor, NKX3.1, plays essential roles in both prostate differentiation and prostate cancer, the mechanisms governing these events are still unclear. Here, we aim to elucidate detailed mechanisms governing Nkx3.1-driven prostate epithelial differentiation and explain how deregulation of such can lead to prostate tumorigenesis. Using an Nkx3.1 mutant mouse model, we find that loss-of-function of Nkx3.1 in the prostate results in the down-regulation of genes associated with prostate differentiation as well as the up-regulation of genes that are not normally expressed in prostate. Interestingly, these mice also develop pre-malignant lesions resembling prostatic intraepithelial neoplasia (PIN). Conversely, gain of function of Nkx3.1 in a fully differentiated non-prostate epithelium is sufficient to induce prostate differentiation in renal grafts in vivo. Using a DNA binding mutant, we show that these activities are mediated via NKX3.1 homeodomain in vitro and in vivo. Exploiting mass spectrometry to identify NKX3.1-interacting proteins, we find that NKX3.1 interacts with the histone methyltransferase G9a and that this interaction is required for induction of prostate differentiation in vitro and in vivo. Finally, we show that these NKX3.1-driven activities are mediated, at least in part, by regulation of target genes such as the male-specific factor UTY (KDM6c). We propose that the NKX3.1-G9a-UTY network is essential for proper prostate differentiation whereas disruption of these activities predisposes to cancer. Citation Format: Clementine Le Magnen, Aditya Dutta, Antonina Mitrofanova, Andrea Califano, Cory Abate-Shen. Identification of an NKX3.1-G9a-UTY regulatory network that controls proper prostate differentiation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2888.