Lipid rafts is important for IR-induced cellular senescence

초록

Cellular senescence, refers to the essentially irreversible growth arrest, occurred by extrinsic stress, including oncogenic mutation and ionizing radiation (IR). Recent extensive studies have established that cellular senescence is an important tumor-suppressive process. Lipid rafts, microdomains of plasma membrane, are enriched in cholesterol and glycosphingolipids, are known to be abundant in various signaling molecules, these microdomains have been involved in many cellular functions, including apoptosis, cell proliferation, cell signaling, and others. Even though it has been suggested that lipid rafts play important roles in chemo- and radio-resistance during cancer treatment, the role of lipid rafts on IR-induced cellular senescence is less defined. In this study, we report that lipid rafts increased during IR-induced cellular senescence in A549 human lung carcinoma cells. When lipid rafts were disrupted using methyl beta cyclodextrin (MβCD) or lovastatin, IR-induced senescence phenotypes disappeared. We also found that disruption of lipid rafts switches cell fate from senescence to apoptosis in cancer cells exposed to IR. Collectively, the composition of lipid rafts might involve in IR-induced cellular senescence.