Abstract A003: Investigating the effect of lipid metabolism on cDC1 dendritic cell cross-presentation in tumor microenvironment

Abstract Dendritic cells, or primary antigen-presenting cells, are critical immune sentinels essential in bridging the body’s adaptive and innate immune responses. Among DC subsets, conventional dendritic cell subset 1 (cDC1) stands out for its unique ability to cross-present antigens, which is crucial for initiating effective cytotoxic T-cell responses against tumors. Unlike normal cells, abnormal lipid accumulation (leading to lipid droplet formation) is observed in several cancers, which is considered one of the major reasons for DC dysfunction. However, very few reports are available on the impact of lipid metabolism on dendritic cells' antigen cross-presentation ability. To achieve this, in-vitro generated cDC1s were cocultured with heat-killed dying tumor cells and subsequently subjected to bulk RNA sequencing. Transcriptomic profiling was performed on cDC1s in the presence or absence of dead cells. Our analysis revealed distinct transcriptome profiles highlighting differential gene expression patterns linked to lipid metabolism, cholesterol regulation, and lipid droplet formation. Furthermore, we carried out various in-vitro metabolic functional assays, such as lipid staining assay, and observed increased lipid drop formation on antigen uptake. We validated this observation using confocal microscopy. In the future, we will reprogram lipid metabolism (using pathway inhibitors and gene knockdowns) and test dendritic cell-based antigen cross-presentation. Our findings suggest a crucial role for lipid metabolism in modulating the cross-presentation machinery of cDC1s within the tumor microenvironment. Understanding the mechanisms underlying this interplay between lipid metabolism and. DC cross-presentation may offer novel insights into the design of immunotherapeutic strategies aimed at harnessing DC-mediated immune responses against cancer. Citation Format: Uddipan Kar, Sreekumar Balan, Nina Bhardwaj. Investigating the effect of lipid metabolism on cDC1 dendritic cell cross-presentation in tumor microenvironment [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr A003.