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, expandedin vitrousing IL-2 stimulation, and then infused back into the patient Rosenberg and Restifo (2015Science34862-68), Bonini and Mondino (2015Eur. J. Immunol.452457-69). 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 Morganet al(1976Science1931007-8). 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 Rosenberget al(1985J. Exp. Med.1611169-88). A mechanistic signaling pathway model was developed to theoretically evaluate the efficacy ofCISHknockout (CISHKO) 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 Donohueet al(1984J. Immunol.1322123-8). Based on the results,CISHknockout 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 thatGSK3B, 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 thatPDCD1, FASandCTLA4can be knocked out in combination withCISHto further enhance T cell activation and prevent exhaustion and apoptosis.