MicroRNA-124 (MiR-124) Inhibits Cell Proliferation, Metastasis and Invasion in Colorectal Cancer by Downregulating Rho-Associated Protein Kinase 1(ROCK1)

Background/aims: MiR-124 inhibits neoplastic transformation, cell proliferation, and metastasis and downregulates Rho-associated protein kinase (ROCK1) in Colorectal Cancer (CRC). The aim of this study was to further investigate the roles and interactions of ROCK1 and miR-124 and the effects of knockdown of ROCK1and MiR-124 in human Colorectal Cancer (CRC).

Methods: Three Colorectal cancer cell lines (HCT116, HT29 and SW620) and one Human Colonic Mucosa Epithelial cell line (NCM460) were studied. The protein expression of ROCK1 was examined by Western-blot and qRT-PCR were performed to examine the expression levels of ROCK1 mRNA and miR-124. Furthermore, We performed transfection of cancer cell line (SW620) with pre-miR-124(mimics), anti-miR-124(inhibitor), ROCK1 siRNA and the control, then observed the affects of ROCK1 protein expression by westen-blot, cell proliferation by EDU (5-ethynyl-2'deoxyuridine assay) and expression levels of ROCK1mRNA by qRT-PCR . A soft agar formation assay, Migration and invasion assays were used to determine the effect of regulation of miR-124 and ROCK1, and survivin on the transformation and invasion capability of colorectal cancer cell.

Results: MiR-124 expression was significantly downregulated in CRC cell lines compare to normal (P < 0.05). In contrast, ROCK1 protein expression was significantly increased in CRC cell lines compared to the normal (P < 0.05), whereas the gene (ROCK1mRNA) expression remained unaltered (P > 0.05). ROCK1 mRNA was unaltered in cells transfected with miR-124 mimic and miR-124 inhibitor, compared to normal controls. There was a significant reduction in ROCK1 protein in cells transfected with miR-124 mimic and a significant increase in cells transfected with miR-124 inhibitor (P < 0.05). Cell proliferation, transformation and invasion of cells transfected with miR-124 inhibitor were significantly increased compared to those in normal controls (P<0.05). However, cell proliferation, transformation and invasion of cells transfected with ROCK1 siRNA were significantly decreased compared to control (P < 0.05).

Conclusions: In conclusion, our results demonstrated that miR-124 not only promoted cancer cell hyperplasia and significantly associated with CRC metastasis and progression, but also downregulated ROCK1 protein expression. More importantly, increased ROCK1 expression or inhibited miR-124 expression may constitute effective new therapeutic strategies for the treatment of renal cancer in the future.