Role Of Na~+/H~+ Exchanger 1 In Apoptosis Of Cells Induced By DNA Damage

Objective:The aim of the study was to compare the effect of Etoposide and irradiation on Na+/H+Exchanger 1 (NHE1) in K562,HL-60 and Jurkat cells, and investigate the Role of NHE1 in Apoptosis of K562,HL-60,Jurkat cells induced by Etoposide and irradiation.Method:Laser scanning confocal microscope was used to determine the pHi of the cells, and by using Real-time quantitative PCR (RQ-PCR) and Western blot methods, the influences of Etoposide and irradiation on NHE1 expression at mRNA and protein levels were determined. Meanwhile, MTT assay was for determining the cytotoxicity of Cariporide on K562,HL-60 and Jurkat cells. And cell apoptosis was measured by DNA ladder and terminal deoxyncleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay.Results:The results indicated that Etoposide and irradiation induced BCR/ABL negative cell lines:HL-60,Jurkat cells, but not the BCR/ABL positive cell line K562 cells apoptosis in 24 h. The pHi of HL-60 and Jurkat cells increased after treatment with Etoposide and irradiation. The expression of NHE1 mRNA level increased after treatment with Etoposide and irradiation, which was revealed by real-time RT-PCR analysis.The NHE1 expression was also up-regulated by Etoposide and irradiation that revealed by western blot assay. Treated with Cariporide blocks Etoposide and irradiation induced alkalinisation and apoptosis.Conclusions:The data indicated that the expression of NHE1 was increased in apoptosis of BCR/ABL negative cells induced by Etoposide and irradiation, the apoptosis need the artificially increasing pH caused by NHE1 higher expression and BCR/ABL inhibit the pathway. 4...