JunD-induced cell proliferation requires MYC signaling in prostate cancer cells

JunD, a member of the AP-1 transcription factor family, is involved in a variety of biological processes including cell proliferation, inflammation, differentiation, apoptosis, and carcinogenesis. We previously showed that JunD is essential for cell proliferation and demonstrated that the knock-down (KD) of JunD in PCa cells resulted in cell cycle arrest in G1-phase concomitant with a decrease in the levels of Id1, c-MYC, and Ki67, but an increased in p21 protein levels. Furthermore, the over-expression of JunD significantly increased proliferation in these cells suggesting that JunD regulates the expression of genes which are required for cell cycle progression. In this present study, employing gene expression profiling, quantitative proteomics, and validation approaches, we demonstrated that JunD KD is associated with distinct gene and protein expression patterns. Comparison integrative analysis by Ingenuity Pathway Analysis (IPA) identified 1) cell cycle control/regulation as the top canonical pathway whose members exhibited a significant decrease in their expression following JunD KD including PRDX3, PEA15, KIF2C, and CDK2, and 2) JunD target genes are involved in cell proliferation, with MYC as the key downstream regulator. Conversely, JunD over-expression induced cell proliferation and the expression of the above JunD target genes including c-MYC. When treated with JQ1, a c-MYC inhibitor, these cells exhibited a significant reduction in cell proliferation and a decrease in JunD target genes. Our data suggest that JunD-mediated cell proliferation involves MYC signaling and inhibiting its target genes may be an effective approach to blocking prostate carcinogenesis Citation Format: Bethtrice Thompson (Elliott), Ana Cecilia Millena, Lilya Matyunina, Mengnan Zhang, Jin Zou, Guangdi Wang, Qiang Zhang, Nathan Bowen, Vanessa Eaton, Gabrielle Webb, Shadyra Thompson, John McDonald, Shafiq Khan. JunD-induced cell proliferation requires MYC signaling in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4306.