p53 Mutation Directs AURKA Overexpression via miR-25 and FBXW7 in Prostatic Small Cell Neuroendocrine Carcinoma

Prostatic small cell neuroendocrine carcinoma (SCNC) is a rare but aggressive form of prostate cancer that is negative for androgen receptor (AR) and not responsive to hormonal therapy. The molecular etiology of this prostate cancer variant is not well understood; however, mutation of the p53 ( TP53 ) tumor suppressor in prostate neuroendocrine cells inactivates the IL8–CXCR2–p53 pathway that normally inhibits cellular proliferation, leading to the development of SCNC. SCNC also overexpresses Aurora kinase A (AURKA) which is considered to be a viable therapeutic target. Therefore, the relationship of these two molecular events was studied, and we show that p53 mutation leads to increased expression of miR-25 and downregulation of the E3 ubiquitin ligase FBXW7, resulting in elevated levels of Aurora kinase A. This study demonstrates an intracellular pathway by which p53 mutation leads to Aurora kinase A expression, which is critically important for the rapid proliferation and aggressive behavior of prostatic SCNC. Implications: The pathogenesis of prostatic SCNC involves a p53 and Aurora Kinase A signaling mechanism, both potentially targetable pathways. Mol Cancer Res; 13(3); 584–91. ©2014 AACR .