We examined the anti-cancer effects and molecular mechanism of simvastatin in human castration-resistant prostate cancer (CRPC) cells, particularly focused on LIN28B and its target molecule, let-7 microRNA (miRNA) among the various target genes of NF-κB. A human CRPC cell line (PC3) was used in the current study. Gene expression patterns were evaluated using real time-PCR and western blot analysis. CCK-8 assay was used for assessing cell viability and proliferation, and a clonogenic assay was adopted to evaluate clonal proliferative capabilities. Induction of apoptotic cell death was analyzed via flow cytometry. Small interfering RNA (siRNA) and short-hairpin RNA (shRNA) were used for manipulating the expression of genes of interest. PC3 showed relatively higher expression levels of LIN28B and lower expression levels of let-7 miRNAs. Simvastatin treatment significantly inhibited cell viability and clonal proliferation in a dose-dependent manner. Importantly, the downregulated let-7 miRNA family was restored after simvastatin treatment. We further observed that human CRPC cells transfected with LIN28B-siRNA or shRNA also showed upregulated let-7 miRNAs. Finally, dual treatment with simvastatin and an NF-κB inhibitor (CAPE) synergistically induced apoptotic cell death, along with reduction of LIN28B expression, and restoration of let-7 miRNAs levels. Our data illustrate that simvastatin remarkably inhibits the growth of human CRPC cells by suppressing NF-κB and LIN28B and subsequently upregulating let-7 miRNAs. Moreover, concurrent treatment with simvastatin and an NF-κB inhibitor synergistically suppressed the growth of human CRPC cells, suggesting a novel therapeutic approach for human CRPC treatment.
PloS one. 2017 Sep 14*** epublish ***
Minyong Kang, Kyoung-Hwa Lee, Hye Sun Lee, Chang Wook Jeong, Ja Hyeon Ku, Hyeon Hoe Kim, Cheol Kwak
Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea., Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea.