Sphingosine kinase 2 negatively regulates 5-fluorouracil-induced apoptosis in human colon cancer cells

Abstract

Objective To explore the role of sphingosine kinase 2(SphK2)in 5-fluorouracil(5-FU)-induced apoptosis in human colon cancer HCT116 cells.Methods Hoechst33342 staining was used to examine the apoptosis morphological changes of HCT116 cells 48hafter treatment with 5-FU;flow cytometry was used to detect the apoptotic ratio of HCT116 cells and the effects of SphK2(down-regulation and over-expression)on 5-FU-induced apoptosis were analyzed.Western blotting analysis was used to examine the changes in the activated forms of SphK2 and apoptotic marker protein in HCT116 cells after exposure to 5-FU.Results 5-FU induced significant apoptosis in HCT116 cells as reflected by apoptosis characteristics-condensation and fragmentation of chromatin.Interference of SphK2 significantly increased 5-FU-induced apoptosis in HCT116 cells compared with non-interfered group(P0.01),accompanied by increased apoptotic marker protein.On the contrary,the apoptosis ratio of the cells with SphK2over-expression was significantly decreased compared with vehicle plasmid-transfected group(P0.01),accompanied by decreased apoptotic marker protein. Moreover,5-FU greatly increased activated SphK2.Conclusion SphK2 negatively regulates 5-FU-induced apoptosis in HCT116 cells.