[Effect of miR-340-5p on proliferation of laryngeal cancer Hep2 cells and its intrinsic molecular mechanism].

Objective:To study the effect of miR-340-5p on the proliferation of laryngeal cancer Hep2 cells and explore its intrinsic molecular mechanism, so as to screen potential biomarkers and targets for the diagnosis and treatment of laryngeal cancer. Method:The expression of miR-340-5p in laryngeal cancer tissues, paracancerous tissues, laryngeal cancer cell lines Hep2 and normal bronchial HBE cell lines was quantitatively analyzed by qRT-PCR; The double luciferase reporter vector was constructed to verify whether STAT3 was a potential target gene of microRNA-340-5p; The miR-340-5p mimics/inhibitor was transfected into Hep2 cells by liposome and verified by qRT-PCR; The CCK-8 method and Annexin V/PI method were used to analyze the proliferation and apoptosis of transfected cells; and Western Blot was used to detect the expression of STAT3 and Wnt/β-catenin pathway-related proteins after transfection. Result:The results of qRT-PCR showed that the level of miR-340-5p in laryngeal cancer tissues and Hep2 cells was significantly lower than that in adjacent tissues and HBE cells, and the expression of miR-340-5p was significantly increased or decreased after overexpression or inhibition; Luciferase activity showed that miR-340-5p directly interacted with target gene STAT3 3'-UTR and negatively regulated its expression; Cell proliferation and apoptosis analysis showed that up-regulation of microRNA-340-5p could significantly inhibit the proliferation and induce apoptosis of Hep2 cells in vitro, and vice versa; Western Blot results showed that the levels of STAT3 and β-catenin, c-Myc, TCF-4, CyclinD1 and ROCK1 in Hep2 cells were significantly lower than those in the control group after over-expression of miR-340-5p, and vice versa. Conclusion:The expression of miR-340-5p is abnormally low in laryngeal cancer tissues and Hep2 cells. It can be used as a potential biological target for diagnosis and treatment of laryngeal cancer by targeting STAT3 gene to negatively regulate Wnt/β-catenin signaling pathway.