RNF2 ablation reprograms the tumor-immune microenvironment and stimulates durable NK and CD4(+) T-cell-dependent antitumor immunity

Expanding the utility of immune-based cancer treatments is a clinical challenge due to tumor-intrinsic factors that suppress the immune response. Here we report the identification of tumoral Ring Finger Protein 2 (RNF2), the core subunit of the Polycomb Repressor Complex 1 (PRC1), as a negative regulator of antitumor immunity in various human cancers, including breast cancer. In syngeneic murine models of triple negative breast cancer, we found that deleting genes encoding PRC1 subunits Rnf2 or BMI1 proto-oncogene, polycomb ring finger (Bmi1), or the downstream effector of Rnf2, Remodeling and Spacing Factor 1 (Rsf1), was sufficient by itself to induce durable tumor rejection and establish immune memory by enhancing infiltration and activation of NK and CD4(+) T-cells, but not CD8(+) T-cells, into the tumor and enabled their cooperativity. These findings uncover an epigenetic reprogramming of the tumor-immune microenvironment which fosters durable antitumor immunity and memory.