Effects And Mechanism Of YAP On Chemosensitivity In Human Laryngeal Squamous Cell Carcinoma

Background: Laryngeal squamous cell carcinoma(LSCC)is one of the most common in the head and neck region.The low survival rate of patients in the middle and late stage is related to the drug resistance of chemotherapy.Cisplatin is widely used in the clinical treatment of laryngeal cancer,but its therapeutic effect is weakened due to its low sensitivity.Yes-associated protein(YAP)is a key protein in the Hippo pathway,which regulates the proliferation,differentiation,metabolism,and apoptosis of tissues and organs.Recent studies have shown that high expression of YAP occurs in a variety of tumors,regulating the development of tumors.The study on the correlation between the expression level of YAP and chemosensitivity has become one of the hot spots.Our previous study found that YAP was highly expressed in laryngeal cancer and correlated with its progression,but the correlation between chemosensitivity and YAP expression in laryngeal cancer is still not clear.Objective: To investigate the effect of YAP expression level on chemosensitivity of cisplatin in LSCC and its possible mechanism after transfection to knockdown or up-regulate YAP expression.Methods: Laryngeal cancer cell lines Hep-2 and Tu686 were transfected with lentivirus to construct an up-regulated,down-regulated,empty vector control group of YAP and a blank control group without transfection.The expression levels of YAP m RNA and protein were confirmed by quantitative real-time PCR(q RT-PCR)and western blot(WB)in each group after cisplatin treatment.CCK-8 and colony formation assays were used to detect the effect of cisplatin on proliferation,clone and inhibition rate of laryngeal cancer cells in each group.Wound-healing assay and Transwell migration and invasion assays were used to identify the change of migration and invasion ability of laryngeal cancer cells in each group after cisplatin treatment.Flow cytometry and TUNEL experiment were used to expose the apoptosis rate of laryngeal cancer cells in each group induced by cisplatin treatment.Finally,the expression of Bcl-2 and Bax were investigated by q RT-PCR and WB.Results: The expression of YAP was significantly down-regulated and up-regulated by lentivirus transfection(P < 0.05).CCK-8 and colony formation assays showed that YAP-sh RNA group significantly inhibited the proliferation and clone ability of laryngeal cancer cells under cisplatin treatment,and enhanced the inhibition effect of cisplatin(P < 0.05).In wound-healing assay and Transwell migration and invasion assays,the healing ability and the number of cells passing through compartments of the YAP-sh RNA group were remarkably fewer than other groups(P<0.01).In flow cytometry and TUNEL assays,the apoptosis rate of laryngeal cancer cells in the YAP-sh RNA group increased significantly(P<0.01).The results of q RT-PCR and WB showed that the expression trend of Bcl-2 protein was consistent with YAP,while the expression of Bax was opposite(P < 0.05).Conclusion: The expression level of YAP can significantly affect the chemosensitivity of LSCC to cisplatin.The possible mechanism is that YAP regulates the apoptosis of LSCC by regulating the transcription level of Bcl-2 and Bax.