The effects of celastrol on the apoptosis and cell cycle arrest of C6 glioma cells and its mechanism

Abstract

Objective To investigate the effects of celastrol on the apoptosis and cell cycle arrest of C6 glioma cells and its mechanism.Methods C6 glioma cells were cultured in vitro.MTT was used to assay cellular proliferation.Fluorescence microscope and transmission electron microscope were used to evaluate the morphological alterations of C5 glioma cells after being incubated with 2.56 μmol/L celastrol.Flow cytometry was used to analyze the alterations of apoptosis rate and cell cycle.Results The inhibitory effects of celastrol on C6 glioma cells were dependent on celastrol concentration and incubation time.Typical morphological alterations of apoptosis were observed under photo-microscope,fluorescence microscope and transmission electron microscope respectively.Flow cytometry showed that the apoptosis rate increased from 1.32％ in control group to 19.34％ in celastrol group,and cellular quantity decreased from 76.42％ to 54.52％ at G0/G1 phase but increased from 9.29％ to 30.50％ at G2/M.Western blotting analysis showed that the expression of apoptosis -related proteins Bc1-2 and XIAP were down-regulated,but Bax,Caspase-3 and cleaved PARP were up -regulated.Moreover,the expression of cell cycle regulator p21,p2 and cyclin B1 were increased,but cdk2 was decreased.Conclusion Celastrol could induce C6 glioma cell apoptosis and cell cycle arrest via influencing the expression of apoptosis related proteins and cell cycle regulators. Key words: Celastrol; C6 glioma cell; Apoptosis; Cell cycle arrest