Mechanistic modeling predicts efficacy of CISH knockout in tumor-infiltrating lymphocytes with synergistic gene editing

Tumor-infiltrating lymphocyte (TIL) therapy is a type of adoptive cell therapy, where the lymphocytes of a cancer patient’s tumor are harvested, expanded in vitro using IL-2 stimulation, and then infused back into the patient[1], [2]. However, even with the use of TIL therapy, cancer cells can survive for various reasons, such as poor lymphocyte infiltration into tumors, chronic activation of the T cell receptor and the immunosuppressive tumor microenvironment[3]. Cytokine-inducible SH2-containing (CISH) protein is a negative regulator of T cell activation, and in a recent clinical trial was knocked out in TILs to improve TIL therapy efficacy[4]. A mechanistic signaling pathway model was developed to theoretically evaluate the efficacy of CISH knockout ( CISH KO) in T cell activation and examine potential alternative target genes that can theoretically be targeted using multiplex gene-editing or drugs to further improve T cell activation and function[5]. Based on the results, CISH knockout increases the transcription of activation biomarkers IL-2 and TNF-α, but also inhibitory biomarkers such as PD1 and FasL. Using global sensitivity analysis, we also found that GSK3B , which is responsible for the deactivation of NFAT, is also predicted to further increase T cell activation when knocked out. In addition, it was predicted that PDCD1 , FAS and CTLA4 can be knocked out in combination with CISH to further enhance T cell activation and prevent exhaustion and apoptosis.