miR-424 targets AKT3 and PSAT1 and has a tumor-suppressive role in human colorectal cancer

BACKGROUND: Recent advances in cancer biology have uncovered critical roles for microRNAs in regulating tumor responses. This study is to elucidate the role of miR-424 in colorectal cancer development. MATERIALS AND METHODS: miR-424 expression was analyzed by qRT-PCR. The role of miR-424 was studied in cell lines and animal models. The downstream targets of miR-424 were determined by microarray analysis. RESULTS: We found that miR-424 expression was downregulated in human colorectal cancer cell lines and patient biopsies. We demonstrated that miR-424 functioned as a tumor suppressor by suppressing colorectal cancer growth in vitro and in vivo and enhancing apoptosis. Using microarray screening, we subsequently presented evidence that miR-424 directly targeted the 3′ untranslated regions of the AKT serine/threonine kinase 3 (AKT3) and phosphoserine aminotransferase 1 (PSAT1) mRNAs via luciferase assay. Furthermore, AKT3 or PSAT1 silencing partially recapitulated the effects of miR-424. CONCLUSION: This newly identified miR-424/AKT3–SAT1 axis may represent a novel therapeutic strategy for future treatment of colorectal cancer.