PrLZ increases prostate cancer docetaxel resistance by inhibiting LKB1/AMPK-mediated autophagy

• Published in: Theranostics 2018, Vol.8 (1), p.109-123
• Main Authors: Zeng, Jin, Liu, Wei, Fan, Yi-Zeng, He, Da-Lin, Li, Lei
• Format: Article
• Language: English
• Subjects: Research Paper
• ISSN: 1838-7640; 1838-7640
• DOI: 10.7150/thno.20356

: Docetaxel-mediated chemotherapy is the first-line standard approach and has been determined to show a survival advantage for metastatic castration-resistant prostate cancer (mCRPC) patients. However, a substantial proportion of patients eventually becomes refractory due to drug resistance. The detailed mechanisms remain unclear. We have previously reported that Prostate Leucine Zipper (PrLZ), a specific oncogene of prostate cancer (PCa), promotes PCa cell growth at the castration-resistant stage, thus suggesting a vital role of PrLZ in the progression of CRPC. In this study, we aimed to investigate the role of PrLZ in docetaxel resistance in PCa, focusing on PrLZ-regulating autophagy pathway. Human PCa PC3, LNCaP and C4-2 cell lines were used as the model system and PCa xenografts and PrLZ-knockout mice were used as the model system . Docetaxel-induced cell death and apoptosis in PCa were determined by MTT and flow cytometry assay. The role of PrLZ on the regulation of autophagy and liver kinase B1/AMP-activated protein kinase (LKB1/AMPK) signaling pathway was analyzed using immunoblotting, immunoprecipitation, siRNA silencing and plasmid overexpression. PrLZ increased docetaxel-mediated drug resistance both and . Mechanistic dissection revealed that PrLZ interacted with LKB1 and further inhibited the activation of LKB1/AMPK signals, which negatively contributed to the induction of autophagy. Moreover, PrLZ/LKB1-mediated autophagy conferred resistance to docetaxel-induced cell death and apoptosis both and . These findings identify a novel role of PrLZ in autophagy manipulation and provide new insight into docetaxel chemoresistance in PCa, suggesting a new strategy for treating mCRPC by targeting this newly identified signaling pathway.