MicroRNA-495 Confers Increased Sensitivity to Chemotherapeutic Agents in Gastric Cancer via the Mammalian Target of Rapamycin (mTOR) Signaling Pathway by Interacting with Human Epidermal Growth Factor Receptor 2 (ERBB2).

BACKGROUND In recent years, the incidence of gastric cancer (GC) has been increasing worldwide. Emerging evidence shows that microRNAs (miRs) may be involved in the pathogenesis of GC. Thus, this study explored the mediatory role of miR-495 in GC chemosensitivity, and investigated the mechanism by which it affects the biological behaviors of GC cells via the mTOR signaling pathway. MATERIAL AND METHODS After GC and paracancerous tissue collection, the positive rate of ERBB2 and mTOR was evaluated by immunohistochemistry. Subsequently, the expression of miR-495, ERBB2, and mTOR was determined by RT-qPCR and Western blot analysis. Next, the targeting relationship between miR-495 and ERBB2 was confirmed by dual-luciferase reporter gene assay. In addition, chemosensitivity and proliferation were detected by MTT assay and apoptosis was assessed by flow cytometry. RESULTS We found higher positive rates of ERBB2 and mTOR and decreased expression of miR-495 in GC tissues and showed that ERBB2 is the target gene of miR-495. Furthermore, we determined that overexpression of miR-495 and silencing of ERBB2 enhanced GC cell chemosensitivity and apoptosis, but inhibited GC cell proliferation. We also found that the effect of miR-495 inhibition was lost when ERBB2 was suppressed. CONCLUSIONS The key findings of our study demonstrate that the miR-495 exerts promotive effects on GC chemosensitivity via inactivation of the mTOR signaling pathway by suppressing ERBB2. The study provides reliable evidence supporting the use of miR-495 as a novel potential target in the chemotherapy of GC.