Susceptibility-Associated Genetic Variation in NEDD9 Contributes to Prostate Cancer Initiation and Progression.

Although American men of European ancestry represent the largest population of patients with prostate cancer, men of African ancestry are disproportionately affected by prostate cancer, with higher prevalence and worse outcomes. These racial disparities in prostate cancer are due to multiple factors, but variations in genomic susceptibility such as SNP may play an important role in determining cancer aggressiveness and treatment outcome. Using public databases, we have identified a prostate cancer susceptibility SNP at an intronic enhancer of the neural precursor expressed, developmentally downregulated 9 (NEDD9) gene, which is strongly associated with increased risk of patients with African ancestry. This genetic variation increased expression of NEDD9 by modulating the chromatin binding of certain transcription factors, including ERG and NANOG. Moreover, NEDD9 displayed oncogenic activity in prostate cancer cells, promoting prostate cancer tumor growth and metastasis in vitro and in vivo. Together, our study provides novel insights into the genetic mechanisms driving prostate cancer racial disparities. SIGNIFICANCE: A prostate cancer susceptibility genetic variation in NEDD9, which is strongly associated with the increased risk of patients with African ancestry, increases NEDD9 expression and promotes initiation and progression of prostate cancer.See related commentary by Mavura and Huang, p. 3764.

ZBTB7A Mediates the Transcriptional Repression Activity of the Androgen Receptor in Prostate Cancer.

Loss of expression of context-specific tumor suppressors is a critical event that facilitates the development of prostate cancer. Zinc finger and BTB domain containing transcriptional repressors, such as ZBTB7A and ZBTB16, have been recently identified as tumor suppressors that play important roles in preventing prostate cancer progression. In this study, we used combined ChIP-seq and RNA-seq analyses of prostate cancer cells to identify direct ZBTB7A-repressed genes, which are enriched for transcriptional targets of E2F, and identified that the androgen receptor (AR) played a critical role in the transcriptional suppression of these E2F targets. AR recruitment of the retinoblastoma protein (Rb) was required to strengthen the E2F-Rb transcriptional repression complex. In addition, ZBTB7A was rapidly recruited to the E2F-Rb binding sites by AR and negatively regulated the transcriptional activity of E2F1 on DNA replication genes. Finally, ZBTB7A suppressed the growth of castration-resistant prostate cancer (CRPC) in vitro and in vivo, and overexpression of ZBTB7A acted in synergy with high-dose testosterone treatment to effectively prevent the recurrence of CRPC. Overall, this study provides novel molecular insights of the role of ZBTB7A in CRPC cells and demonstrates globally its critical role in mediating the transcriptional repression activity of AR. SIGNIFICANCE: ZBTB7A is recruited to the E2F-Rb binding sites by AR and negatively regulates the transcriptional activity of E2F1 on DNA replication genes.