Fatty Acids Differentially Induce Lipid Droplet Formation in HeLa Cells

Background/Objectives: Long-chain fatty acids induce lipid droplet formation in several cell types including cancer cells. These lipid droplets have been shown to accumulate in various cancers and are dysregulated in many pathologies. Thus, this study was designed to examine the many unique long-chain fatty acids and their abilities to induce lipid droplet formation in cancer cells. Methods: HeLa human cervical cancer cells were incubated with individual fatty acids and live-stained for lipid droplets. This study analyzed four saturated, four monounsaturated, and nine polyunsaturated (4 omega-3, 4 omega-6, and 1 omega-9) fatty acids. This diversity of fatty acids was chosen to highlight any important non-uniform differences in the regulation of lipid droplet formation by unsaturated fatty acids. The area of the lipid droplets and the number of lipid droplets per cell were measured and compared between the different fatty acid conditions. Results: Unsaturated fatty acids induced lipid droplets differently compared to saturated fatty acids. Further, an inverse relationship was established between average area of lipid droplets and the average number of lipid droplets per cell. Finally, two perilipin genes (PLIN1/2) involved in lipid droplet formation were shown to have significantly higher expression with the two polyunsaturated fatty acids (alpha- and gamma-linolenic acid) versus the saturated fatty acid (stearic acid) condition. Conclusions: Together, different fatty acids produce structurally different lipid droplets. It will be important to further investigate the biochemistry and mechanistic differences in the formation of these lipid droplets under these specific long-chain fatty acid conditions.