MicroRNA-106a suppresses prostate cancer proliferation, migration and invasion by targeting tumor-derived IL-8

BACKGROUND: Tumor-derived interleukin-8 (IL-8) promotes tumorigenesis and progression of prostate cancer (PCa). MicroRNAs (miRNAs) are noncoding regulatory RNAs and their dysregulation is known to be implicated in carcinogenesis. However, the post-transcriptional mechanism of IL-8 via miRNAs is not fully understood. This study was intended to investigate whether miR-106a could affect the progression of PCa via targeting IL-8 or not. METHODS: Using bioinformatics analysis, we postulated that IL-8 might be post-transcriptionally regulated by miR-106a. This was validated by dual reporter gene assays that miR-106a could bind to the predicted site of IL-8 mRNA. To determine the biological effects of miR-106a on PCa cells (PC-3 and DU145), MTT, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), migration and invasion assays were performed. RESULTS: We found that miR-106a was barely expressed in PCa cells, whereas IL-8 was aberrantly upregulated. Elevated miR-106a could reduce IL-8 expression by directly binding the 3'-UTR of IL-8. Overexpression of miR-106a in PCa cells triggered cell apoptosis and suppressed cell proliferation, migration, and invasion. CONCLUSIONS: This research showed that miR-106a could function as a tumor-suppressor by decreasing IL-8 levels in PCa.