Abstract LB-281: The role of POU5F1B in prostate cancer.

POU5F1B is the one of the pseudogenes of POU5F1 (also known as Oct3, Oct4) with protein-coding potential. It is localized on chromosome 8q24.21, inside of the 1.2 Mb “gene desert” between the FAM84B and the c-MYC gene, which is closely associated with prostate cancer risk. Recent studies showed that POU5F1B, but not POU5F1, is expressed in prostate tissue and is overexpressed in prostatic carcinoma, compared to normal prostatic tissue surrounding the carcinoma. However, the role of POU5F1B in prostate cancer is still unknown. Through in silico analysis of dataset HG-U95A, we found that POU5F1B expression is increased in prostate tumor and markedly increased in metastatic tumors. Western blot analysis revealed a marked increase in POU5F1B expression in prostate cancer cells when compared to non-tumorigenic RWPE-1 cells. To study the role of POU5F1B in prostate cancer, we cloned POU5F1B from prostate cancer cells, sequenced the amplicons, and found several polymorphism. We made pCDH-myc-POU5F1B constructs and expressed POU5F1B in prostate cancer cell lines LNCaP, DU145, and PC-3. Overexpression of POU5F1B in LNCaP, DU145 and PC3 cells can increase cell invasion using Boyden chamber assay. Overexpression of POU5F1B in LNCaP cells also promotes colony formation in soft agar. We also found that DU145 cells with POU5F1B overexpression lost cell-cell contact, compared to DU145-pCDH vector cells, and further found that CDH1 expression is downregulated in DU145-POU5F1B cells. Depletion of POU5F1B reduced the tumor forming ability of LNCaP cells in vivo. The data collectively suggest an important role of POU5F1B in prostate tumor formation and progression. Citation Format: Hongmei Jiang, Man-Tzu Wang, Daotai Nie. The role of POU5F1B in prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-281. doi:10.1158/1538-7445.AM2013-LB-281