The Role Of PETN In Immune Escape Of Oral Squamous Cell Carcinoma And Its Molecular Mechanism

Objective:Oral squamous cell carcinoma(OSCC)accounted for 90% of oral and maxillofacial malignancies,and was the most common malignant tumor.At present,the five-year survival rate of OSCC after treatment was only50% to 60%.In recent years,with the in-depth study of tumor immunology,people had realized that the immune escape of tumor had caused the lower immune response of the body to the tumor.Through the understanding of tumor immune escape mechanism,it was of great significance to the clinical immunotherapy,prognosis and evaluation of curative effect.Phosphatase and tension homolog deleted on chromosome 10(PTEN)was the first tumor suppressor gene found to have bispecific Phosphatase activity.By playing the role of phosphatase,it participated in regulating many important signaling pathways in the cell,including the PI3K/AKT signaling pathway.The lower expression of PTEN was found in a variety of human tumors including oral squamous cell carcinomas.PTEN expression was related to the occurrence,development and prognosis of tumor.Two oral squamous cancer cells with different expression of PTEN and a normal oral mucosa cell were used in the study.The expression of immunosuppressive factor(IL-6,IL-10,VEGF)and costimulatory molecule(B7-H1)were tested by techniques of molecular biology.After the intervention of PI3K/AKT signaling pathway inhibitors,the concentration of immunosuppressive factors(IL-6,IL-10,VEGF)and costimulatory molecules(B7-H1)were detected.The aim was to explore the specific pathways and molecular targets of immune escape of oral squamous cell carcinoma and to reveal the role and molecular mechanism of PTEN inactivation in immune evasion of oral squamous cell carcinoma.Materials and methods:1.Experimental materialsOSCC line SCC-4 was purchased from ATCC,USA.OSCC line Tca8113 was purchased in Shanghai Ninth People's Hospital.Normal oral mucosa cell line HGFs(normal control,from normal gingival tissue)originated from Pathology Section of Stomatology Hospital of Hebei Province.2.Experimental methods2.1 Immunohistochemistry and Western Blot assay were used to detect the expression of PTEN protein in three cell lines(HGFs,TCa8113 and SCC-4).2.2 ELISA assay was employed to detect the contents of immunosuppressive factor((IL-6?IL-10 and VEGF)and costimulatory molecule(B7-H1)in three cell lines(SCC-4,TCa8113 and HGFs).2.3 After the intervention of PI3K/AKT signaling pathway inhibitors,the concentration of immunosuppressive factors(IL-6,IL-10,VEGF)and costimulatory molecules(B7-H1)were detected using ELISA assay.Results:1.The results of immunohistochemistry and Western Blot analysis showed that the expression of PTEN protein was normal in the normal oral mucosal cell line HGFs,moderate in the oral squamous carcinoma cell line TCa8113,and low in the oral squamous carcinoma cell line SCC-4.2.ELISA showed that the concentrations of immunosuppressive factor(IL-6,IL-10,VEGF)in HGFs,TCa8113 and SCC-4 were successively increased,and there were significant differences between each of the two cells.(P< 0.05).3.ELISA showed that the concentrations of costimulatory molecule(B7-H1)in HGFs,TCa8113 and SCC-4 were successively increased,and there were significant differences between each of the two cells.(P < 0.05).4.After intervention with PI-3K inhibitor LY294002,the concentrations of immunosuppressive factors(IL-6,IL-10,VEGF)in HGFs,TCa8113 and SCC-4 were all reduced,and the SCC-4 was the most significant among threecell lines.(P < 0.05).5.After intervention with PI-3K inhibitor LY294002,the concentration of costimulatory molecule(B7-H1)in HGFs,TCa8113 and SCC-4 were all reduced,and the SCC-4 was the most significant among three cell lines.(P<0.05).6.Correlation analysis showed that PTEN was significantly negatively correlated with content of IL-6 IL-10 VEGF and B7-H1 respectively,r =0.985,0.97,0.945,0.975,P< 0.05.Conclusion:1.The lower expression of PTEN gene can give rise to cause the more expression of immunosuppressive factor(IL-6,IL-10 and VEGF)and help OSCC to escape from immune surveillance.2.The lower expression of PTEN gene can give rise to cause the more expression of costimulatory molecule(B7-H1)and help OSCC to escape from immune surveillance.3.PTEN gene has negative regulatory effect on the immunosuppressive agents and costimulatory molecule and this regulatory is achieved by signaling pathway PI3K/AKT.