Androgen-Responsive Oncogenic lncRNA RP11-1023L17.1 Enhances c-Myc Protein Stability in Prostate Cancer

Abstract

Long noncoding RNAs (lncRNAs) have been found as novel participants in the pathophysiology of prostate cancer (PCa), which is predominantly regulated by androgen and its receptor. The biological function of androgen-responsive lncRNAs remains poorly understood. Here, we identified that lncRNA RP11-1023L17.1, which is highly expressed in PCa. RP11-1023L17.1 expression, can be directly repressed by the androgen receptor in PCa cells. RP11-1023L17.1 depletion inhibited the proliferation, migration, and cell cycle progression, and promoted the apoptosis of PCa cells, indicating that RP11-1023L17.1 acts as an oncogene in PCa cells. Microarray results revealed that RP11-1023L17.1 depletion downregulated the c-Myc transcription signature in PCa cells. RP11-1023L17.1 depletion-induced cellular phenotypes can be overcome by ectopically overexpressed c-Myc. Mechanistically, RP11-1023L17.1 represses FBXO32 mRNA expression, thereby enhancing c-Myc protein stability by blocking FBXO32-mediated c-Myc degradation. Our findings reveal the previously unrecognized roles of RP11-1023L17.1 in c-Myc-dependent PCa tumorigenesis.