抑制钠氢交换蛋白1促进低氧诱导的K562细胞分化  

Inhibition of NHE1 Promotes Hypoxia-induced Differentiation of K562 Leukemic Cells

作　　者：金薇娜 王建 常国强 蔺亚妮 王立洪 李华文 高伟 李庆华 庞天翔 

机构地区：[1]中国医学科学院、北京协和医学院血液学研究所、血液病医院,实验血液学国家重点实验室,天津300020

出　　处：《中国实验血液学杂志》2011年第3期661-665,共5页Journal of Experimental Hematology

基　　金：天津市自然科学基金(编号09JCZDJC17300);高等学校博士学科点专项科研基金(编号20091106110038)

摘　　要：本研究主要探讨低氧微环境对慢性髓系白血病细胞系K562分化的影响及钠氢交换蛋白1(NHE1)在该过程中的作用。利用低氧模拟物CoCl2或于低氧(2%O2、5%CO2和93%N2)环境中培养K562细胞,应用激光共聚焦显微镜测定细胞内pH值(intracellular pH,pHi),瑞氏染色观察细胞形态,实时定量RT-PCR检测基因表达,Western blot技术检测MAPK磷酸化水平的改变。结果表明:与对照组相比,低氧培养的K562细胞表现出成熟相关的形态学改变,并伴随CCAAT/增强子结合蛋白(C/EBPα)的mRNA水平上调;特异性NHE1抑制剂Cariporide预处理能够促进低氧诱导的K562细胞分化,Cariporide处理后K562细胞的P38和ERK5蛋白激酶磷酸化水平显著增强。结论 :低氧及低氧模拟物能够诱导K562细胞系分化,抑制NHE1活性协同促进低氧诱导的K562细胞分化,其机制可能是通过增强细胞内MAPK蛋白激酶磷酸化水平促进分化。This study was purposed to investigate the effect of hypoxia microenvironment on K562 leukemic cell differentiation, and characteristics of NHE1 involvement in this process. The K562 cells were treated with hypoxia-mimical agent CoCl2 or under actual hypoxia culture, and the specific NHE1 inhibitor Cariporide was used to inhibit NHE1 activity. The fluorescent probe BCECF was used for pHi measurements. Gene expression was analyzed by RT-PCR. The morphological characteristzs was determined by Wright＇s staining. Signaling pathways were detected by Western blot using phosphospecific antibodies. The results indicated that the hypoxia or mimetic hypoxia favored K562 cells differentiation with up-regulation of C/EBPα. Moreover, treatment with Cariporide under hypoxia synergistically enhanced leukemia cell differentiation. Treatment with Cariporide increased levels of phosphorylated ERK5 and P38 mitogen-activated protein kinase （MAPK）. It is concluded that the hypoxia or mimetic hypoxia can induce the differentiation of K562 cells, the inhibition of NHE1 activity can promote the hypoxia-induced K562 cell differentiation. The enhancement of hypoxiainduced K562 differentiation by Cariporide via MAPK signal pathway suggests a possible therapeutic target of NHE1 under hypoxia microenvironment in the treatment of leukemias.

关 键 词：钠氢交换蛋白1 低氧诱导分化 K562细胞 CoCl2 

分 类 号：R733.7[医药卫生—肿瘤]