Summary
A complex set of pathways maintain an immunosuppressive tumor microenvironment (TME). Current cancer immunotherapies primarily rely on monoclonal antibodies targeting immune checkpoints, blocking one target at a time. Here, we devise Multiplex Universal Combinatorial Immunotherapy via Gene-silencing (MUCIG), as a versatile cancer immunotherapy approach. We harness CRISPR-Cas13d to efficiently target multiple endogenous immunosuppressive genes on demand, allowing us to silence various combinations of multiple immunosuppressive factors in the TME. Intratumoral AAV-mediated administration of MUCIG (AAV-MUCIG) elicits significant anti-tumor activity with several Cas13d gRNA compositions. A simplified off-the-shelf AAV-MUCIG with four gene combination (PGGC: Pdl1, Galectin9, Galectin3 and Cd47) has anti-tumor efficacy across different tumor types and shows abscopal effect against metastatic cancer. AAV-PGGC remodeled the TME by increasing CD8+ T cell infiltration and reducing myeloid-derived immunosuppressive cells (MDSCs). Combining AAV-PGGC with Anti-Gr1 antibody that targets MDSCs achieves synergistic effect against metastatic cancer, which reduces tumor burden and extends survival.
Competing Interest Statement
The authors have declared no competing interest.