IM-9 세포에 있어서 세라마이드에 의한 세포주기 변화와 아포프토시스

Cell Cycle Alteration and Apoptosis Induced by Ceramide in IM-9 Cells

Sphingolipids play important roles in cell regulation and signal transduction. Recently, a sphingomyelin cycle has been described in which activation of neutral sphingomyelinase leads to the breakdowm of sphingomyelin and the generation of ceramide. Ceramide, in turn, has emerged as a candidate intracellular mediator for the action of certain cell agonists and has multiple biologic actions. Ceramide is a potent suppressor of cell growth and an inducer of apoptosis. The present studies show that exposure of IM-9 cells to ceramide resulted in internucleosomal cleavage of DNA, yielding laddered patterns of oligonucleosomal fragments characteristic of apoptosis. DNA fragmentation induced by ceramide was also confirmed by diphenylamine assay. The effect of ceramide on cell cycle progression was also studied. The addition of ceramide increased G1 phase distribution in cell cycle, Cell cycle-related cyclin D1 gene expression was decreased in a time-dependent manner. These results suggest that apoptosis induced by ceramide is related to cell cycle associated with the alteration of cell cycle in IM-9 cells.