BCL2 inhibition stimulates dendritic cell function for improved anticancer immunotherapy

Recently we developed a dendritic cell (DC) genotype-phenotype screening platform that is based on CRISPR/Cas9-mediated gene editing of immortalized DC precursors. Whole genome screening for gain-of-function phenotypes led to the identification of BCL2 as a DC-specific immune checkpoint. Genetic or pharmacological inhibition of BCL2 similarly enhanced the antigen presentation capacity of conventional type-1 dendritic cells (cDC1) and mediated T cell-dependent anticancer immunity. The therapeutic anticancer efficacy of the BCL2 inhibitor venetoclax in mice was further increased when combined with a PD-1-targeted immune checkpoint inhibitor. In sum, we delineated a novel strategy of dual checkpoint blockade for cancer immunotherapy in which improvement of DC antigen presentation and avoidance of T cell exhaustion can be advantageously combined.