ABSTRACT
Castration-resistant prostate cancer (CRPC) has become a significant problem in the current treatment of prostate cancer (PCa) with the characteristics of high metastatic potential, resistance and easy recurrence. The abnormal activation of JAK2/STAT3/MCL-1 and NF-κB has been confirmed as the main reason for the development of CRPC. We previously found that ß-elemonic acid (ß-EA) as a natural triterpene has potential anti-inflammatory and anti-osteosarcoma effects with lower toxicity. But it remains unknown whether it had effects on CRPC. The present research in vitro and in vivo systematically investigates anti-cancer effects and mechanisms of ß-EA on human CRPC. ß-EA treatment resulted in apoptotic cell death in human PCa cells by mitochondrial apoptotic pathways (including up-regulation of cleaved caspase-3, cleaved PARP, and Bax or down-regulation of Bcl-2). Besides, ß-EA at relatively lower levels inhibited colony-forming, the migration and invasion potential of PCa cells, indicating its anti-proliferation and anti-metastasis activities. After exploring the potential mechanism, our results suggested that it subsequently inhibited the activation of JAK2/STAT3/MCL-1 and NF-κB signaling pathway by the administration of ß-EA. The silencing of NF-κB/p65, JAK2 and STAT3, respectively, increased the sensitivity of the PCa cells to ß-EA induced apoptosis. Moreover, ß-EA exhibited a strong affinity with its essential proteins JAK2, RELA/p65, NF-κBIα/IκBα by molecular docking analysis. Importantly, ß-EA retards tumor growth in a murine xenograft model, consistent with our study in vitro. Taken together, findings from this study reveal for the first time the potential role and mechanisms of ß-EA on CRPC.
