Abstract POSTER-BIOL-1314: Investigating fatty acid beta-oxidation in ovarian cancer cells

Abstract Purpose: To investigate the contribution of fatty acid beta-oxidation to the total energy budget of ovarian cancer cells. Experimental procedures: Several ovarian cancer cells lines (OVKATE, OVSAHO, NIHOVCAR3) as well as a patient derived primary cell line (GD13-13P) were utilized for all experiments. The Seahorse Flux Analyzer in conjunction with several metabolic inhibitors including etomoxir (a carnitine palmitoyltransferase 1 inhibitor), 2-deoxy glucose, FCCP and rotenone were utilized in these experiments to evaluate the oxygen consumption rate(ORC) and extracellular acidification rate(ECAR) of cells at their basal and post metabolic inhibitor state. OCR and ECAR were used as markers for mitochondrial respiration and lactate production, respectively. NIHOVCAR3 cells were co-cultured with differentiated 3T3L1 adipocytes and then subjected to BODIPY fluorophore (493/503) fatty acid staining and confocal microscopy to investigate the potential relationship between ovarian cancer cells, adipocytes and metabolism. Summary of data: All ovarian cancer cell lines demonstrated a significant decrease in their OCR with the administration of etomoxir (OVSAHO 78%, OVKATE 71%, NIHOVCAR 75%, GD13-13P 66%, p<0.001). The simultaneously measured ECAR was significantly increased in most cell lines (OVSAHO 62%, OVKATE 142%, GD13-13P 82%, p<0.001) after administration of etomoxir, while unchanged in the NIHOVCAR3 cell line. Metabolic activity was further evaluated by determining the effect administration of 2-deoxy glucose (2DG) had on the basal OCR and ECAR of OVKATE and OVSAHO cells. The basal OCR of both cell lines was essentially unchanged with the administration of 2DG; however a significant decrease was seen with the subsequent administration of etomoxir. The co-culture of NIHOVCAR3 cells and differentiated adipocytes resulted in a marked increase in visualization of BODIPY staining of cytoplasmic free fatty acids compared to NIHOVCAR3 cells grown without co-culture (control). The addition of the fatty acid synthase inhibitor orlistat to the culture media resulted in a marked decrease in the cytoplasmic staining of the control cells; however NIHOVCAR3 cells grown in co-culture had persistent cytoplasmic BODIPY staining. Conclusions: These results suggest that ovarian cancer cell lines, as well as primary ovarian cancer cells, derive a significant portion of their energy from fatty acid beta oxidation, despite the presence of abundant glucose. Additionally, co-culture of ovarian cancer cells with adipocytes appears to provide ovarian cancer cells with exogenous free fatty acids donated by the adipocytes. These results help to further the concept that metastasis of ovarian cancer to fatty rich areas such as the omentum and mesentery may provide a metabolic advantage. Citation Format: Karyn J. Hansen, Bennett Van Houten. Investigating fatty acid beta-oxidation in ovarian cancer cells [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1314.