恶性肿瘤患者红细胞膜带3蛋白表达及其对K562细胞生长的影响

Expression of Band 3 Protein on Erythrocytes of Malignant Tumor Patients and Its Impact on Proliferation of K562 Cells

背景与目的:带3蛋白介导Cl-/H CO3-的跨膜交换,从而调节细胞内pH值。有学者证实,Cl-/H CO3-交换的异常可引起细胞内pH值明显改变,使细胞发生增殖或凋亡。本研究旨在探讨红细胞膜带3蛋白的表达及其对K562细胞生长的影响。方法:以SPQ为荧光探针测定8例恶性肿瘤患者红细胞膜带3蛋白的阴离子转运活性,W estern blot检测带3蛋白表达。转染带3蛋白膜段结构域cDNA至K562细胞,观察带3蛋白膜段结构域表达后对K562细胞阴离子转运活性及细胞增殖的影响。结果:7例恶性肿瘤患者红细胞膜带3蛋白的离子转运活性明显增强,5例蛋白质表达增强。同时发现带3蛋白膜段结构域表达于K562细胞膜后,对K562细胞生长有一定促进作用。结论:带3蛋白在部分恶性肿瘤患者红细胞膜表达增强,可作为恶性肿瘤的一种潜在标志物。

BACKGROUND & OBJECTIVE: Membrane domain of band 3 protein (mdb3) mediates transmembrane exchange of chloride and bicarbonate, and regulates intracellular pH. It has been found recently that abnormality of CI-/HCO3- exchange, which mainly leads to change of intracellular pH, may be involved in cell proliferation and apoptosis. This study was to explore expression of band 3 protein on erythrocytes, and its impact on proliferation of K562 cells. METHODS: Anion transport activity of band 3 protein on erythrocytes of 8 malignant tumor patients was measured using SPQ fluorescent probe. Expression of band 3 protein was detected by Western blot. Plasmid pYD1-mdb3 was constructed, and transfected into K562 cells. Cl- transport activity and proliferation of K562 cells were detected after transfection. RESULTS: Of the 8 patients, 7 showed increase of anion transport activity on erythrocytes, 5 showed increase of band 3 protein expression. To some extent, expression of mdb3 enhanced proliferation of K562 cells. CONCLUSION: Expression of band 3 protein is enhanced on erythrocytes of some malignant tumors, and might be a candidate marker of malignant tumors.