MicroRNA-206 inhibits the proliferation, migration and invasion of colorectal cancer cells by regulating the c-Met/AKT/GSK-3β pathway

Abstract

An imbalance in microRNA (miRNA/miR) expression is closely associated with tumorigenesis and progression. miR-206 is downregulated in different types of tumors, including colorectal cancer (CRC). However, the effects of miR-206 on the progression of CRC, and its underlying molecular mechanisms are yet to be elucidated. The present study aimed to investigate the effects of miR-206 on the proliferation, migration and invasion of colorectal cancer cells, and determine its potential molecular mechanism. The results of the present study demonstrated that the expression levels of miR-206 and c-Met were affected in HCT116 and SW480 cells by transfected with miR-206 mimic, inhibitor or small interfering RNA-c-Met. A Dual-luciferase reporter assay was performed to identify the miRNA targets. Cell proliferation, migration and invasion assays were also performed. The results demonstrated that overexpression of miR-206 significantly decreased the viability of HCT116 and SW480 cells. The results of the Transwell assay indicated that the cell migratory and invasive abilities were inhibited following transfection with miR-206 mimic. As a target of miR-206, knockdown of c-Met significantly suppressed cell viability, migration and invasion. In addition, c-Met knockdown or overexpression of miR-206 inhibited activation of the AKT/GSK-3β pathway. Collectively, these results suggest that miR-206 suppresses the proliferation, migration and invasion of CRC cells by targeting the c-Met/AKT/GSK-3β pathway.

Keywords: c-Met; colorectal cancer; invasion; microRNA-206; migration; proliferation.

Figure 1.

Effects of miR-206 on the proliferation, migration and invasion of colorectal cancer cells. (A) Reverse transcription-quantitative PCR analysis was performed to detect miR-206 expression in HCT116 and SW480 cells following transfection with miR-206 mimic or inhibitor for 48 h. (B) Viability of HCT116 and SW480 cells was assessed via the MTT assay following transfection with miR-206 mimic or miR-206 inhibitor. (C and D) Cell migratory and invasive abilities were assessed via Transwell assays. *P<0.05, **P<0.01, ***P<0.001. miR, microRNA; NC, negative control.

Figure 2.

c-Met is a direct target of miR-206. (A) Complementary sequences of miR-206 binding site in WT c-Met 3′-UTR and MUT c-Met 3′-UTR. (B) Luciferase activity was measured to assess the binding ability of miR-206 on the c-Met 3′-UTR WT or MUT in SW480 cells. (C) Spearman's correlation analysis was performed to determine the correlation between miR-206 and c-Met expression levels in SW480 cells. (D) mRNA and (E) protein expression levels of c-Met in HCT116 and SW480 cells were detected via reverse transcription-quantitative PCR and western blot analyses, respectively. *P<0.05, **P<0.01, ***P<0.001. miR, microRNA; WT, wild-type; UTR, untranslated region; MUT, mutant; NC, negative control.

Figure 3.

Effects of c-Met on the proliferation, migration and invasion of colorectal cancer cells. (A) Western blot analysis was performed to detect c-Met protein expression in HCT116 and SW480 cells following transfection with si-c-Met. (B) Cell viability was assessed via the MTT assay following transfection for 24, 48 and 72 h. (C and D) Cell migratory and invasive abilities were assessed via Transwell assays. *P<0.05, **P<0.01, ***P<0.001. si, small interfering; NC, negative control.

Figure 4.

Effects of c-Met and miR-206 on the AKT/GSK-3β signaling pathway. (A) Western blot analysis was performed to detect protein expression levels of p-AKT and p-GSK-3β in HCT116 and SW480 cells transfected with si-c-Met. (B) Western blot analysis was performed to detect protein expression levels of p-AKT and p-GSK-3β in HCT116 and SW480 cells transfected with miR-206 mimic or inhibitor. miR, microRNA; p-, phosphorylated; si, small interfering; NC, negative control.