Abstract 5387: Modeling physiological lipid availability of tumors to improve in vitro studies of cancer cell lipid metabolism

Lipids are highly crucial in cellular physiology and pathology. They are the main structural components of cellular membranes and play critical roles in metabolism, signaling, and other core processes. Many studies of lipid metabolism, both in cancer and other fields, rely on the results of in vitro tissue culture experiments. Generally, in vitro culture systems use media containing non-physiological levels of nutrients, including high levels of critical nutrients like glucose and glutamine. Recently, several groups have generated culture media with physiological levels of polar metabolites, which can correct some tissue culture-related artifacts. However, these new-generation media still use traditional serum and still represent severe lipid starvation conditions. In lipid-deprived environments, cells respond by activating the sterol regulatory element binding protein (SREBP) pathway, a transcriptional regulator of global lipid metabolic gene expression. Our SREBP transcription factor signature scores comparing human tumor samples to established cancer cell lines growing in TM showed dramatic activation of SREBP in cell lines relative to tumors, supporting traditional tissue culture being a highly lipid-starved environment. We hypothesized that these lipid-starved conditions impact cancer cell behavior in vitro and that developing a more physiological lipid medium will maintain more accurate cell metabolic characteristics. To study this, we have generated two new physiological lipid media - one that mimics lipid levels found in human plasma (HSLM) and one that mimics the lipid levels found in the tumor microenvironment (TILM). The lipidomic analysis confirmed that HSLM closely resembles the lipidome of human serum, while TILM more accurately aligns with the lipid profile of tumor interstitial fluid (TIF). We found that cell lines were unable to survive when cultured in HSLM. However, cancer cell lines adapted to TILM, reduced de novo lipogenesis and proliferation rate and had a similar fatty acid profile to in vivo mouse tumors compared to TM. In the future, we would like to comprehensively study how cells change their metabolism, signaling, and lipid profile to see whether cells cultured in TILM better represent primary tumor metabolism. Citation Format: Mete E. Ozgurses, Vipin S. Rawat, Kelly O. Conger, Huiping Zhao, Patrick B. Jonker, Alexander Muir, Jonathan L. Coloff. Modeling physiological lipid availability of tumors to improve in vitro studies of cancer cell lipid metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5387.