Influence of environmental medium on membrane fatty acid composition of Reuber H35 hepatoma cells

Cell membrane proteins are sensitive to their fatty acid environment; however, the effects of those fatty acids are not completely understood. In this work, we have optimized a model for the study of membrane protein regulation, which allows the investigation of lipid metabolism in cultured tumor cells. The membrane fatty acid composition of Reuber H35 hepatoma cells was modified by enriching phospholipids in individual fatty acids of different length and degree of saturation. Lauric, myristic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were supplemented to the culture medium of cells growing in presence or absence of lipoproteins. The four fatty acids were incorporated into membrane phospholipids in a dose-dependent manner. Lauric and myristic acids were actively metabolized, increasing percentages of longer and unsaturated chain fatty acids, but they did not modify the unsaturated index. As expected, EPA and DHA significantly decreased the unsaturated index. Incorporation of EPA and DHA was accompanied of a significant decrease of total monounsaturated fatty acids and an increase of total saturated fatty acids. Our results demonstrate that Reuber H35 hepatoma cells constitute a suitable model to manipulate the lipid composition of the cell membranes and perform functionality studies on the membrane proteins in response to their lipid environment.