MicroRNA-181b targets cAMP responsive element binding protein 1 in gastric adenocarcinomas.

MicroRNAs are a class of small endogenous non-coding RNAs that function as post-transcriptional regulators. In our previous study, we found that miR-181b was significantly downregulated in human gastric adenocarcinoma tissue samples compared to the adjacent normal gastric tissues. In this study, we confirm the down-regulation of miR-181b in human gastric cancer cell lines versus the gastric epithelial cells. Overexpression of miR-181b suppressed the proliferation and colony formation rate of gastric cancer cells. miR-181b downregulated the expression of cAMP responsive element binding protein 1 (CREB1) by binding its 3' untranslated region. Overexpression of CREB1 counteracted the suppression of growth in gastric cancer cells caused by ectopic expression of miR-181b. These results indicate that miR-181b may function as a tumor suppressor in gastric adenocarcinoma cells through negative regulation of CREB1.