MiR-22-3p suppresses cell growth via MET/STAT3 signaling in lung cancer

MiR-22-3p has been reported to be down-regulated in several cancers, but its expression pattern and roles in lung cancer is unclear. Given the crucial role of microRNAs in cancer progression, we examined the expression and function of miR-22-3p in lung adenocarcinoma. MiR-22-3p expression in lung cancer tissues and cell lines was measured by qRT-PCR. Cell proliferation was measured by WST-1 and colony formation assays were used to reveal the role of miR-22-3p in lung cancer in vitro. MiR-22-3p was notably down-regulated in lung cancer tissues as compared to normal lung tissues, but it was not associated with the clinical characteristics of tumor stage, differentiation and patient's smoking status. Colony formation ability and cell proliferation were suppressed by miR-22-3p mimics in lung cancer cell lines. Mechanistically, miR-22-3p mimics could reduce MET and STAT3 protein expression and induce apoptosis as measured by PARP protein. We conclude that miR-22-3p may play a tumor suppressor role via inhibiting MET-STAT3 signaling and have potential to be a therapeutic target and biomarker in lung adenocarcinoma.