Abstract 6531: Anti-tumor immune function of NR2F6, an orphan nuclear receptor, in stromal cells

Abstract Growing evidence points to the importance of the tumor microenvironment (TME) in tumor growth control, progression, and therapy response. Among those is the greater understanding of immune system components within the TME as mediators of tumor growth control. NR2F6 is an orphan nuclear receptor, which was shown to serve as an immune intrinsic checkpoint component and has been suggested to elicit tumor-intrinsic suppression of anti-tumor immunity. Correspondingly, genetic depletion of NR2F6 in CD8 T cells abrogates the immune-activating cytokines (e. g. , IL-2, IFNg). In addition, genetic ablation of NR2F6 in melanoma cells activates CD8 T cell-mediated anti-tumor immunity partly by suppressing the expression of tumor-intrinsic immune repressors NACC1 and FKBP10. Notably, combined genetic ablation of tumor cells (NR2F6 KO melanoma) and stroma cells (NR2F6 KO mouse) resulted in a more pronounced inhibition of tumor growth compared with ablation of either tumor cells or TME. The latter provides the foundation for screening NR2F6 inhibitors, which are expected to have a strong systemic (tumor inhibition and immune cell activation) effect on tumor growth. Interestingly, single-cell transcriptomic data from human tumors identified high expression of NR2F6 in stroma cells, cancer-associated fibroblasts (CAFs), and tumor-associated endothelial cells (TAEs). Consistent with these, scRNAseq analysis of mouse melanoma revealed higher expression of NR2F6 in SMA+ immune suppressive myo-CAFs than in immune activating CAFs. Studies that directly reveal the role of stromal NR2F6 in anti-tumor immunity and tumor growth and the state of NR2F6 inhibitors will be discussed. Citation Format: Hyungsoo Kim, Yongmei Feng, Marria Radaeva, Eduard Sergienko, Artem Cherkasov, Ze'ev A. Ronai. Anti-tumor immune function of NR2F6, an orphan nuclear receptor, in stromal cells abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 6531.