ACYL-COA SYNTHETASE 4 MODULATES MITOCHONDRIAL FUNCTION AND METABOLISM IN BREAST CANCER CELLS.

BENZO YANINA; PRADA, JESICA G.; DATTILO, MELINA A.; LOPEZ PAULA; CASTILLO, ANA FERNANDA; MORI SEQUEIROS GARCÍA, MARÍA DE LAS MERCEDES; RINGELMANN, PAOLA; PODEROSO, CECILIA; MALOBERTI, PAULA MARIANA

Mendoza

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

Acyl- CoA synthetase 4 (ACSL4) is an enzyme that catalyzes acyl-CoA synthesis from long chain fatty acid, being arachidonicacid its preferred substrate. In breast cancer, ACSL4 promotes tumor aggressiveness by increasing migration, proliferation andinvasion. In this context, there is evidence of dysregulation of mitochondrial function, mitochondrial mass and subcellular spatialorganization in cancer. Also, it is known that alteration of energy metabolism allows tumor cells to survive and spread even inchallenging conditions. In MCF-7 breast cancer cells, a previous bioinformatic analysis showed that ACSL4 overexpression couldmodulate mitochondrial master regulatory genes involved in energy and respiratory metabolism. The aim of this work is todetermine whether mitochondrial function and metabolism are modulated by ACSL4 in breast cancer cells. For this purpose, mRNAlevels of genes related to mitochondrial function such as NRF-1/2, UCP2 and ANT1 were evaluated in MCF-7 overexpressingACSL4 cells by qPCR. mRNA levels of these genes were significantly increased by ACSL4 overexpression related to control cells. Moreover, protein levels of mitochondrial complex III, VDAC1 and nuclear NRF-1 were significantly increased by ACSL4overexpression in MCF-7 cells with respect to control cells. Respiratory and glycolytic function were studied using the SeahorseXF Cell Mito Stress Test and GlycoStress Test respectively. We observed a significant increase in oxygen consumption rate andbasal respiration, maximal respiration, proton leak and respiratory reserve capacity in MCF-7 cells overexpressing ACSL4.Glycolytic function analysis demonstrated a significant increase in several parameters induced by ACSL4 such as extra acidificationrate, non-glycolytic acidification, glycolysis and glycolytic capacity. On the other hand, results showed a significant decrease inthe percentage of glycolytic reserve in MCF-7 overexpressing ACSL4. These results are consistent with the increase inmitochondrial activity induced by ACSL4 in this cellular model observed by MitotrackerRed staining. Mitochondrial mass wasmeasured by MitotrackerGreen staining and analyzed by flow cytometry. Results showed a significant decrease of this parameterin MCF-7 cells that overexpress ACSL4 related to control cells. These results suggest that ACSL4 stimulates a greatermitochondrial turnover and a better response to high energy demand situations which in turn provides to the cells a greater capacityfor invasion migration and proliferation. Thus, ACSL4 could not only confer an adaptive advantage to tumor cells by inducingglycolytic metabolism that favors tumor development but also could protect mitochondria against oxidative stress increasingantioxidant factors and promoting the expression of genes involved in mitochondrial biogenesis. Altogether, the results of this workextend the knowledge about the role of ACSL4 in respiration and mitochondrial function in breast cancer cells.