Effects And Mechanisms Of E-cadherin Mediated Immune Escape In EGFR-mutant Non-small Cell Lung Cancer

Background:Tyrosine kinase inhibitors(TKIs)are the first-line treatment in NSCLC patients with EGFR mutations,but the overall survival of patients is not ideal,and other therapies need to be sought.Although results at the cellular and animal levels support that EGFR-mutated NSCLC can benefit from anti-PD-1/PD-L1 treatment,this is not the case in humans.It is urgent to explore the molecular mechanism of Immune checkpoint inhibitors(ICIs)tolerance of EGFR-mutated NSCLC and improve the effect of immunotherapy.METHODS:Firstly,the expression of E-cadherin in EGFR-mutated and wild-type NSCLC cells and tumor tissues was analyzed by Bioinformatics,and verified by Western Blot and immunohistochemical staining,respectively.Secondly,the expression of E-cadherin receptor KLRG1 on peripheral NK cells and CD8~+T cells of NSCLC patients with EGFR mutation and wild-type was explored.The expression of IFN-γin peripheral KLRG1~+CD8~+T cells was detected by flow cytometry and the cytotoxic function of tumor infiltrated KLRG1~+CD8~+T cells was analyzed by Bioinformatics.Subsequently,the inhibitory effect of E-cadherin on cytotoxic function of CD8~+T cells was investigated in vitro,and the expression of E-cadherin was further knocked down to verify the immunosuppressive effect of E-cadherin on CD8~+T cells,and the specific mechanism was discussed.Finally,we explored whether E-cadherin could affect the cytotoxic activity and proliferation ability of CD8~+T cells through exosomal secretion.RESULTS:We found that E-cadherin expression is up-regulated in EGFR-mutated NSCLC cells and tumor tissues.In addition,peripheral blood of NSCLC patients with EGFR mutation and wild-type was collected,and flow cytometry showed that the expression of E-cadherin receptor KLRG1 was higher in peripheral CD8~+T cells of EGFR-mutated NSCLC.Subsequently,we found that the expression of IFN-γin peripheral KLRG1~+CD8~+T cells was higher than that in KLRG1~-CD8~+cells,and peripheral KLRG1~+CD8~+T cells exerts effective function,but the tumor infiltrated KLRG1~+CD8~+T cells exhibited impaired cytotoxicity.Further,we demonstrated that EGFR-mutated NSCLC cells with high expression of E-cadherin can inhibit the anti-tumor activity of CD8~+T cells,mainly by inhibiting the expression of cytotoxic IFN-γand Granzyme B in CD8~+T cells in vitro.Finally,exosomes of EGFR-mutated and wild-type NSCLC cells were separated by overspeed centrifuge method,and we uncovered that EGFR-mutated NSCLC cells can secrete exosomes-derived E-cadherin,and then inhibit the anti-tumor activity and proliferation of CD8~+T cells.CONCLUTION:The expression of E-cadherin and its receptor KLRG1 is increased in EGFR-mutated NSCLC.E-cadherin-KLRG1 axis inhibits the anti-tumor activity of CD8~+T cells,and plays an important role in immune escape of EGFR-mutated NSCLC,and may provide a new immunotherapy target for EGFR-mutated NSCLC.