1 Oncogenes and Tumor Suppressors Q 1 2 miRNA - 302 b Suppresses Human Hepatocellular Carcinoma 3 by Targeting AKT 2 4 5

7 Abstract 8 miRNAs (miR) play a critical role in human cancers, including hepatocellular carcinoma. Although miR-302b 9 has been suggested to function as a tumor repressor in other cancers, its role in hepatocellular carcinoma is 10 unknown. This study investigated the expression and functional role of miR-302b in human hepatocellular 11 carcinoma. The expression level of miR-302b is dramatically decreased in clinical hepatocellular carcinoma 12 specimens, as comparedwith their respective nonneoplastic counterparts, and in hepatocellular carcinoma cell lines. 13 Overexpression of miR-302b suppressed hepatocellular carcinoma cell proliferation and G1–S transition in vitro, 14 whereas inhibition ofmiR-302b promoted hepatocellular carcinoma cell proliferation andG1–S transition. Using a 15 luciferase reporter assay, AKT2was determined to be a direct target ofmiR-302b. Subsequent investigation revealed 16 that miR-302b expression was inversely correlated with AKT2 expression in hepatocellular carcinoma tissue 17 samples. Importantly, silencing AKT2 recapitulated the cellular and molecular effects seen upon miR-302b 18 overexpression, which included inhibiting hepatocellular carcinoma cell proliferation, suppressing G1 regulators 19 (Cyclin A, Cyclin D1, CDK2) and Q4 increasing p27Kip1 phosphorylation at Ser10. Restoration of AKT2 20 counteracted the effects of miR-302b expression. Moreover, miR-302b was able to repress tumor growth of 21 hepatocellular carcinoma cells in vivo. Mol Cancer Res; 1–13. 2013 AACR. 22 23 24 25 Introduction