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

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. 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. 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. 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.