Reduction of miR-132-3p contributes to gastric cancer proliferation by targeting MUC13

Abnormal expression of epidermal growth factor receptor (EGFR) signaling and microRNAs (miRNAs) has been widely seen in gastric cancer. The present study focused on the miRNAs that regulate human epidermal growth factor receptor (HER) activation through mucin 13 (MUC13). The protein level of MUC13 was demonstrated to be significantly increased in gastric cancer tissues compared with normal tissues by western blot analysis and immunohistochemistry. TargetScan bioinformatic predictions indicated that miRNA (miR)-212-3p and miR-132-3p may bind to the 3'-untranslated region of MUC13. Further investigation revealed that miR-132-3p was significantly decreased in gastric cancer tissues compared with normal tissues, whereas miR-212-3p expression was unaffected. Luciferase assays and western blot confirmed MUC13 as a target gene of miR-132-3p. Inhibition of miR-132-3p enhanced gastric cancer cell migration through activation of HER2, extracellular signal-regulated kinase (ERK) and Akt serine/threonine kinase (Akt) signaling, which was a similar effect to that of MUC13 overexpression. In summary, reduction of miR-132-3p may contribute to gastric cancer proliferation by targeting MUC13.