Metabolic Depletion of Sphingolipids Does Not Alter Cell Cycle Progression in Chinese Hamster Ovary Cells

Abstract

The cell cycle is a sequential multi-step process essential for growth and proliferation of cells comprising multicellular organisms. Although a number of proteins are known to modulate the cell cycle, the role of lipids in regulation of cell cycle is still emerging. In our previous work, we monitored the role of cholesterol in cell cycle progression in CHO-K1 cells. Since sphingolipids enjoy a functionally synergistic relationship with membrane cholesterol, in this work, we explored whether sphingolipids could modulate the eukaryotic cell cycle using CHO-K1 cells. Sphingolipids are essential components of eukaryotic cell membranes and are involved in a number of important cellular functions. To comprehensively monitor the role of sphingolipids on cell cycle progression, we carried out metabolic depletion of sphingolipids in CHO-K1 cells using inhibitors (fumonisin B1, myriocin, and PDMP) that block specific steps of the sphingolipid biosynthetic pathway and examined their effect on individual cell cycle phases. Our results show that metabolic inhibitors led to significant reduction in specific sphingolipids, yet such inhibition in sphingolipid biosynthesis did not show any effect on cell cycle progression in CHO-K1 cells. We speculate that any role of sphingolipids on cell cycle progression could be context and cell-type dependent, and cancer cells could be a better choice for monitoring such regulation, since sphingolipids are differentially modulated in these cells.