AIM:To investigate the role of ClC-3 chloride channel in the promotion of radio sensitization of na-sopharyngeal carcinoma CNE-2Z cells by dihydroartemisinin(DHA).METHODS:MTT was used to detect the inhibito-ry effect of DHA on the viability of CNE-2Z cells and normal nasopharyngeal epithelial NP69-SV40T cells,the radio sensi-tization effect of DHA on CNE-2Z cells was detected by cloning assay,the expression of ClC-3 protein was detected by Western blot,the expression of ClC-3 protein was down-regulated by siRNA technology,and the chlorine current of cells was recorded by whole cell patch-clamp technology.RESULTS:(1)Compared with NP69-SV40T cells,DHA selective-ly inhibited the proliferation of CNE-2Z cells,with IC10 values of(13.020±4.831)μmol/L and(5.244±1.050)μmol/L,respectively(P＜0.01).(2)The results of clonal formation experiments showed that DHA had a radio sensitizing effect on CNE-2Z cells,with a radio sensitization ratio of 1.9.(3)DHA could activate the chlorine channel of CNE-2Z cells and produce an outward chlorine current,but had no effect on the chlorine channel of NP69-SV40T cells.(4)DHA promoted the expression of ClC-3 chloric channel protein in CNE-2Z cells(P＜0.01).(5)Chlorine channel blocker NPPB could in-hibit the radio sensitizing effect of DHA on CNE-2Z cells by 1.84 times,and also inhibited the chlorine current activated by DHA.(6)the down-regulation of CNE-2Z ClC-3 protein could inhibit the radio sensitization effect of DHA on CNE-2Z cells by 4.19 times,and the activation of chlorine current by DHA on CNE-2Z cells was no longer produced.CONCLU-SION:DHA has a radio sensitizing effect on nasopharyngeal carcinoma CNE-2Z cells,which is likely to be related to the activation of ClC-3 chloride channel.