Abstract
miRNAs are non-coding RNAs that have functions to regulate gene expression and play essential roles in a variety of biological processes of cancers. In the present study, we report miR-143 acts as a tumor suppressor in human oral squamous cell carcinoma (OSCC). The expressions of miR-143 are down-regulated in both OSCC cell lines and patient samples compared with normal adjacent tissues. We found overexpression of miR-143 in oral cancer cell lines suppresses cell migration, cellular glucose metabolism and proliferation. Moreover, overexpression of miR-143 promoted apoptosis and significantly caused cell cycle arrest at G1 stage. The colony formation of oral cancer cells was also suppressed by miR-143 We identified hexokinase 2 (HK2) as a direct target of miR-143 in oral cancer cells. Our data show that miR-143 complementary pairs to the 3'-UTR of HK2 in oral cancer cells, leading to the inhibition of glycolysis in vitro and in vivo Moreover, knockdown of HK2 by siRNA in oral cancer cells inhibited glucose metabolism, proliferation and migration. Recovery of glucose metabolism by overexpression of HK2 in miR-143 overexpressing cells restores the cell migration and proliferation, suggesting that the miR-143-mediated cancer suppression is through the direct inhibition of HK2. In summary, the present studies highlight miR-143 as a tumor suppressor in OSCC by the suppression of cell migration, glucose metabolism and proliferation through directly targeting HK2, rendering miR-143 a therapeutic strategy for the treatment of clinical OSCC patients.