Development of breast adipose-cancer co-culture model to decipher the impact of lipid heterogeneity on triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype accounting for 10-15% of all breast cancer cases. It is further characterized by high resistance to chemotherapy and low survival rates. Lipid composition and patient demographics, such as obesity, have been associated with TNBC, and obesity related fatty acids in the tumor microenvironment (TME) can drive metabolic inflammation and promote TNBC progression. Despite this, the unique impact of the TNBC subtype on lipid composition within the TME, and its subsequent role as an energy source for TNBC cell growth and disease progression, remains poorly understood. Therefore, deciphering the lipid heterogeneity in the TME of TNBC will provide novel insights into TNBC progression and ultimately unveil novel therapeutic targets. Prior work by our collaborative group has demonstrated a heterogeneous distribution of lipids across TNBC tumors compared to matched normal tissue. Further, there was an increase in distinct lipid species, including linoleic acid (LA) and oleic acid (OA). We hypothesized that the distinct TNBC lipid composition enriched in LA and OA fuels TNBC progression. To understand the impact of TNBC-driven TME remodeling in the context of lipid composition, we developed a model of TNBC enriched for LA and OA through the co-culture of differentiated breast adipose-derived ASCs (BrASC) and TNBC. We demonstrated that an adipocyte-TNBC co-culture model can be successfully constructed by treating BrASC with fatty acids distinct to TNBC during differentiation to adipogenic lineage; fatty acid production and uptake was confirmed with quantitative BODIPY fluorescence microscopy. TNBC cell viability was confirmed with quantitative fluorescence microscopy, and up to 200μM of lipid can be added to the system while retaining cell viability. Our results demonstrated that BrASC incorporated exogenous lipids during adipogenic differentiation, and the co-culture of these BrASC with TNBC provided lipid transfer. Overall, our results suggest that an i n vitro model can be developed to interrogate the impact of heterogeneous lipids on the TNBC-TME. Future studies will include evaluating the impact of an altered lipid profile in BrASC on TNBC progression. In conclusion, the long-term goal of this research is to develop an in vitro tool to study the impact of the unique lipid TME on TNBC, thus improving upon current pre-clinical models for TNBC.