USP7 Regulates The Expression Of PCDH1 In Laryngocarcinoma And Its Clinical Significance

Objective:After the expression of ubiquitin specific peptidase 7(USP7)in laryngeal cancer Hep-2 cells was knocked down by lentivirus,we screened a series of differentially expressed genes by RNA-seq technique.In order to verify the changes in the expression of PCDH1(protocadherinl),we plan to demonstrate the expression of PCDH1 in laryngeal cancer cells and tissues through in vitro cell experiments and Immunohistochemistry,so as to understand the role of PCDH1 in the pathogenesis of laryngeal cancer and explore the differences in the expression of PCDH1 between the two.According to the related pathological characteristics,the relationship between its expression and clinicopathological characteristics and overall survival rate of patients was determined.Methods:1.The laryngeal cancer cell line model of Hep-2 with reduced USP7 gene expression was established by using the lentiviral vector with USP7-specific sequence constructed by our research group in the early stage,and then the expression of PCDH1 was detected at the gene and protein levels by RT-PCR and Westernblot.2.Eighty laryngeal cancer tissues and forty-nine normal tissues beside carcinoma in department of Otolaryngology,Head and Neck Surgery,Affiliated Hospital of North Sichuan Medical College were obtained from September 2016 to April 2020.The expression of PCDH1 was examed by Immunohistochemistry staining.We also analyzed the relationships of its expression with clinicopathological characteristics and prognosis.SPSS22.0 was used to analyze the positive rate of proteins between different clinicopathological characteristics as a statistical analysis tool.3.Through review and telephone follow-up,we obtained 72 cases’ prognosis.The correlation between prognosis and PCDH1 expression and related clinical features was analyzed for survival,and the survival curve was plotted.Results:1.After transfection of siRNA into Hep-2 cells,the expression of USP7 mRNA and protein in experimental group was low.RT-PCR and Western blot detected that the expression of PCDH1 mRNA and protein in laryngeal cancer cells after USP7 knockdown was significantly increased.2.Immunohistochemical staining showed that PCDH1 was mainly expressed in cell membrane and nucleus,with diffuse spots and mostly brownish yellow staining.The positive expression rates in laryngeal cancer tissues and paracancerous tissues were 57.50%and 10.20,respectively.Statistical analysis showed that PCDH1 expression in laryngeal cancer tissue was correlated with clinical stage and degree of differentiation of patients.Univariate Log-rank test showed that TNM stage,tumor differentiation degree and PCDH1 expression were related to prognosis of patients with laryngeal cancer(P<0.05).Further Cox regression analysis showed that TNM stage and PCDH1 expression were related to prognosis of patients(P<0.05).Conclusion:The expression of PCDH1 was correlated with TNM stage and tumor differentiation degree in patients with laryngeal cancer.The expression of PCDH1 may be negatively regulated by USP7,which may be one of the mechanisms affecting the prognosis of patients with laryngeal cancer.