Signal transduction pathway ERK1/2 involved in cytotoxicity of NK cell lines / 中国免疫学杂志

ABSTRACT

Objective:To determine the roles of constitutively activated signal transduction pathway ERK1/2(p44/42 MAPK)in controlling cytotoxicity or proliferation activity of natural killer cell lines.Methods:Whole cell extracts from human NK cell lines(YT,IL 2 independent;NK 92,IL 2 dependent) was used in Western blot to detect the constitutively activated signal transduction pathway(s) in human NK cell lines. Specific inhibitor PD098059 was used to abrogate phosphorylation of ERK1/2 for further evaluation. A MTT based method was applied to analyze the cytotoxicity and proliferation capability of NK cell lines before and after specific inhibition of ERK1/2 activation by PD098059.RT PCR protocol was applied to analyze the cytotoxic related molecules possibly engaged with the ERK1/2 signal transduction pathway.Results:Western blot showed that signal transduction pathway ERK1/2,NF ?B and STAT3 was constitutively phosphorylated in two representative human NK cell lines YT and NK 92 which killed NK sensitive K562 target efficiently,other sigal pathways(STAT1,STAT6,p38 MAPK and PI 3K) were not activated.ERK1/2 inhibitor PD098059 apparently inhibited cytotoxicity of NK cell lines but did not influence their proliferation potential, RT PCR analysis revealed that the expression of lytic related molecules including IFN?,FasL,and perforin was downregulated to distince degree by PD098059 as it blocked the phosphorylation of ERK1/2 in NK cell lines.Conclusion:The constitutively phosphorylated signal pathway ERK1/2 in NK cell lines mainly involved in transducing signals controlling the cytotoxic capacity but not the proliferation potential of NK cells,ERK1/2 regulated the lytic capacity of NK cells by inducing the expression level of lytic related molecules including IFN?、FasL and perforin. [