Study on the Safety and Tolerability of PD-1 Knockout Tumor-infiltrating T Cells (TILs) in the Treatment of Advanced Colorectal Cancer

TIL from tumor tissue of advanced colorectal cancer patients were cultured, modified and expanded in vitro, and then transfused back to the patients after quality control. The safety and efficacy of the treatment were investigated. The fundamental cause of oncogenesis lies in the accumulation of gene mutations. A large number of gene mutations in tumor cells lead to changes in the encoded amino acid sequence, resulting in the production of tumor-specific proteins. Human T cells recognize tumor-specific peptides (tumor neoantigens) that are presented on the MHC molecules on the surface of tumor cells, leading to T cell enrichment within the tumor. However, due to the immunosuppressive effect of tumors through various ways, the enriched T cells in tumors cannot effectively kill tumor cells. One of the most common examples is that tumors up-regulate the expression of immune checkpoint protein PD-L1, which binds to PD-1 on the surface of T cells and inhibits T cell function. Therefore, in this study, we will obtain tumor tissue via surgery resection or biopsy, and then isolate TIL cells in the tumor under GMP conditions, and further use gene editing technology to knockout PD-1, the obtained gene-edited T cells will have the characteristics of specific recognition of tumor cells, but not sensitive to the immunosuppressive function of tumor cells, so as to achieve the therapeutic effect on tumor patients.