Targeting reverses immune evasion to enhance immunotherapy in hepatocellular carcinoma.

Background: Immune escape is an important feature of hepatocellular carcinoma (HCC). The overall response rate of immune checkpoint inhibitors (ICIs) in HCC is still limited. Revealing the immune regulation mechanisms and finding new immune targets are expected to further improve the efficacy of immunotherapy. Our study aims to use CRISPR screening mice models to identify potential targets that play a critical role in HCC immune evasion and further explore their value in improving immunotherapy.

Methods: We performed CRISPR screening in two mice models with different immune backgrounds (C57BL/6 and NPG mice) and identified the immunosuppressive gene as a candidate for further investigation. Flow cytometry was used to analyze the impact of on immune cell infiltration and T-cell function. RNA sequencing was used to identify the changes in neutrophil gene expression induced by and alterations in downstream molecules. The therapeutic value of the combination of inhibitors and anti-programmed cell death protein-1 (PD-1) antibody was also explored.

Results: , as an immune inhibitory target, significantly promoted tumor growth in immunocompetent mice rather than immune-deficient mice. inhibited cytotoxic T lymphocytes (CTLs) function by inducing neutrophil chemotaxis. promoted self-chemotaxis of neutrophil expression profiles and neutrophil extracellular traps (NETs) formation to block T-cell activity through leucine-rich α-2-glycoprotein 1 (LRG1). A significant synergistic effect was observed when inhibitor was in combination with anti-PD-1 antibody.

Conclusions: We identified a potential HCC immune evasion target, , through CRISPR screening. induces neutrophil recruitment and NETs formation through the intermediate molecule LRG1, leading to the inhibition of CTLs function. Targeting can enhance CTLs function and improve the efficacy of ICIs.