[MicroRNA-152 and microRNA-448 inhibit proliferation of colorectal cancer cells in vitro by targeting Rictor].

ABSTRACT

OBJECTIVE: To screen the microRNAs (miRNAs) targeting Rictor and investigate their effects in regulating the biological behaviors of colorectal cancer (CRC). METHODS: Human colorectal cancer cell line KM12SM was transfected with the miRNAs targeting Rictor identified by prediction software to test inhibitory effects of these miRNAs on Rictor expression using qRT-PCR and Western blotting. Dual luciferase reporter assay was used to further confirm the binding of these miRNAs to the 3'UTR of Rictor mRNA. Cell survival and colony formation assays were used to investigate the effects of these miRNAs on survival and colony formation in KM12SM cells. RESULTS: miR-152 and miR-448 were identified as the Rictor-targeting miRNAs, which significantly inhibited the expression of Rictor in KM12SM cells (P < 0.05). The two miRNAs were confirmed to bind to the 3'UTR of Rictor mRNA and significantly inhibited luciferase activity in KM12SM cells (P < 0.01, P < 0.05); they also showed activities of posttranscriptional modulation of Rictor. Overexpression of miR-152 and miR-448 both significantly inhibited the growth and colony formation of KM12SM cells. CONCLUSIONS: miR-152 and miR-448 can down-regulate the protein expression of Rictor by targeting Rictor mRNA to negatively regulate the growth and colony formation of colorectal cancer cells.