Deregulation of microRNA-188-5p in prostate carcinoma and effects on proliferation and metastasis of prostate carcinoma cell lines

Abstract

Objective To measure the expression level of microRNA (miRNA, miR)-188-5p in prostate carcinoma (PCa) and investigate its biological functions on prostate carcinoma cell lines. Methods In 30 PCa and 40 benign prostatic hyperplasia (BPH) samples, quantificational real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-188-5p in prostate tissues. In different prostate cell lines, miR-188-5p expression was also detected using RT-qPCR. The miR-188-5p mimic was re-introduced into PC-3 and LNCaP cells by Lipfectamine 2000. The function of miR-188-5p on PCa cells was explored by colony formation assays, Transwell migration and invasion assays. The candidate targets for miR-188-5p were investigated using prediction algorithm provided by miRanda. Luciferase activity was measured using the dual luciferase reporter assay system. Results The expression level of miR-188-5p was significantly lower in PCa tissues than in pericarcinous and BPH tissues (0.996±0.024, 0.990±0.094, 0.385±0.031; P 0.05). It was also found that miR-188-5p was significantly down-regulated in PCa cell lines as compared with that in RWPE-1 (0.409±0.034, 0.358±0.024, 0.255±0.018, 1.022±0.012; P<0.01). The colony formation assays showed that ectopic miR-188-5p expression significantly inhibited colony formation compared to control PC-3 and LNCaP cells (21±5, 47±3; 25±4, 51±5; P<0.01). We next found ectopic miR-188-5p expression significantly reduced the cell invasion and migration compared to control PC-3 and LNCaP cells (P<0.05). Through computational analysis, the binding site for miR-188-5p at 3’-untranslated region (3’-UTR) of lysosome-associated protein transmembrane 4 beta (LAPTM4B) was depicted. The luciferase-based assay validated LAPTM4B was regulated by miR-188-5p. Conclusion The miR-188-5p was significantly down-regulated in PCa. Restoration of miR-188-5p in PCa cells significantly suppresses proliferation, migration and invasion in vitro. The miR-188-5p can negatively regulate LAPTM4B expression by directly binding to its 3’-UTR. Key words: MicroRNA-188-5p; Lysosome-associated protein transmembrane 4 beta; Prostate carcinoma