Targeting the PRMT1-cGAS-STING signaling pathway to enhance the anti-tumor therapeutic efficacy.

Activating innate immune signaling in tumor cells to enhance anti-tumor immunity and increase T cell-mediated killing is the core objective of tumor immunotherapy. PRMT1, one of the most crucial PRMTs, plays a critical role in tumor progression and innate immunity. Recent research revealed that PRMT1 can inhibit the enzymatic activity of cGAS in part through PRMT1-mediated Arg methylation, thereby suppressing the anti-tumor immune response of cells. As such, inhibiting or knocking down PRMT1 can synergistically enhance the efficacy of anti-PD-1 immunotherapy by activating the cGAS-STING signaling pathway. Here, we provide a comprehensive description of the two key signaling components, PRMT1 and cGAS, in the PRMT1-cGAS-STING signaling pathway for therapeutic intervention to augment anti-tumor immunity. By understanding the specific physiological functions and regulatory mechanisms of PRMT1, as well as the extensive post-translational modifications (PTMs) of cGAS, we have identified several compounds and drugs that can directly target PRMT1 or cGAS, and/or indirectly target PRMT1 upstream regulators or cGAS-post-translational modifying enzymes as potential means to activate the cGAS-STING signaling pathway. However, further investigation is needed on the efficacy of combining this pathway activation with anti-PD1 therapy. This review suggests that targeting the PRMT1-cGAS-STING pathway with immune checkpoint inhibitors is likely a promising approach in tumor immunotherapy.