Abstract 1275: In vivo functional CRISPR screens identifies metabolic dependencies mediating triple negative breast cancer lung metastasis

Abstract Metastasis is responsible for about 90% of cancer-related mortality. Throughout the metastatic cascade, cancer cells requires substantial metabolic rewiring to adapt the nutrient micro-environmental changes enabling dissemination and seeding in distant organs. Recent insights into importance of the tumor-intrinsic metabolic reprograming has been implicated in immune escape, yet altered immune responses imposed by tumor metabolism during metastasis are poorly understood. Here, we generated genetic perturbations in triple-negative breast cancer cells using metabolism-focused CRISPR knockout library and performed in vivo screens in both immunocompetent and immunodeficient mice. By comparing enriched sgRNAs in lung metastases or primary tumors, we identify loss of one gene related to long chain fatty acid (LCFA) β-oxidation (FAO) potentiates metastatic dissemination in immunocompetent mice but no in immunodeficient mice, suggesting that impaired FAO in tumor cells promotes breast cancer lung metastasis through an lymphocytes-dependent manner. We confirmed individual sgRNAs targeting this FAO gene from the primary screen dramatically accelerate metastasis in different breast cancer orthotopic models. Specifically, we find that low expression of this gene in primary tumors of advanced breast cancer patients with high grade tumors and positive lymph nodes (LN+) is associated with reduced overall survival. In addition, deletion of this gene generates an immunosuppressive microenvironment in the lung metastatic tumors with increased neutrophils, monocytes and decreased TNFα+-IFNγ+ CD8+ T cells. Mechanistically, impaired FAO in tumor cells causes mitochondria imbalance under lipid metabolism stress, consequently triggers inflammatory response on establishing a neutrophil-rich metastatic niche via mitochondrial nucleic acid-driven innate immunity. Altogether, our data provides a new insight on how tumor cell lipid metabolism impacting immune interplay during metastatic progression, nominating potential anti-tumor immunotherapies. Citation Format: Xiaoyong Wang, Shu-ting Chou, Verra Ngwa, Yoonha Hwang, Breelyn Karno, Deanna Edwards, Jin Chen. In vivo functional CRISPR screens identifies metabolic dependencies mediating triple negative breast cancer lung metastasis 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 1275.