Objective:To investigate the effect and mechanism of G protein-coupled receptor, class C, group 5, member A (GPRC5A) on the proliferation and apoptosis of laryngeal cancer cells (LCC).Methods:From June 2015 to December 2018, 22 patients with laryngeal cancer were selected from the People's Hospital of Xinjiang Uygur Autonomous Region. Tumor tissue samples and paracancerous tissue were collected. The expression of GPRC5A in laryngeal cancer tissues and laryngeal cancer cells was detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and Western blot; pcDNA3.1-GPRC5A and control plasmid pcDNA3.1 were transfected into Hep-2 and AMC-HN-8 cells respectively. Methyl thiazolyl tetrazolium (MTT) assay was used to detect the effect of GPRC5A on the proliferation of laryngeal cancer cells; V-FITC/PI assay was used to detect the effect of GPRC5A on the apoptosis of laryngeal cancer cells; DCFH-DA was used to detect the level of reactive oxygen species (ROS) in laryngeal cancer cells; Western blot was used to detect the protein expression of vascular endothelial growth factor (VEGF), E-cadherin and vimentin in laryngeal cancer cells.Results:(1) The expression of GPRC5A in laryngeal carcinoma tissues and laryngeal carcinoma cells was lower than that in adjacent tissues and normal laryngeal epithelial cells ( P<0.05). (2) Overexpression of GPRC5A could inhibit the proliferation of laryngeal cancer cells and the expression of VEGF, E-cadherin and vimentin ( P<0.05); overexpression of GPRC5A could significantly increase the level of ROS, decrease the level of NAD + and adenosine triphosphate (ATP) ( P<0.05), increase the apoptosis rate ( P<0.05), and significantly increase the protein expression of Caspase-3 and Caspase-9 ( P<0.05). Overexpression of GPRC5A could inhibit the expression of signal transducer and activator of transcription 3/suppressor of cytokine signal transduction 3/myelocytomatosis oncogene (STAT3/SOCS3/C-MYC) pathway related proteins ( P<0.05); the expression of GPRC5A in 22 patients with laryngeal cancer were negatively correlated with STAT3 ( P<0.05). (3) STAT3 and C-MYC inhibitors significantly inhibited the expression of VEGF and E-cadherin in Hep-2 cells ( P<0.05), promoted apoptosis ( P<0.05), decreased the level of interleukin (IL)-6 in Hep-2 cells ( P<0.05), and significantly increased the level of ROS in Hep-2 cells. Conclusions:It suggests that GPRC5A inhibits proliferation and epithelial-mesenchymal transition (EMT), induces oxidative stress and apoptosis of LCC cells potentially by regulating STAT3/SOCS3/C-MYC signaling. These results provide a molecular basis for clinical treatment and diagnosis of laryngeal cancer.

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.

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.