Shp-2过度表达与人白血病细胞恶性增殖相关性研究

Correlation of overexpression of Shp-2 tyrosine phosphatase and proliferative potential of human leukemia cells

目的研究Shp-2酪氨酸蛋白磷酸酶对白血病细胞恶性增殖的影响。方法应用W estern b lot和RT-PCR技术分析白血病细胞和正常造血细胞样本Shp-2蛋白和mRNA表达水平;采用反义寡核苷酸技术和流式细胞术分析下调Shp-2表达对白血病细胞增殖与凋亡的影响。结果与正常造血细胞相比,磷酸化Shp-2蛋白在白血病细胞中呈过度表达状态,Shp-2与-βactin比值在白血病组(n=36)、正常骨髓造血细胞组(n=8)及正常外周血细胞组(n=12)分别为1.23±0.74、0.163±0.088和0.034±0.045。同样,Shp-2 mRNA在白血病细胞样本中呈高表达状态,其与-βactin比值在白血病组(n=26)和正常造血细胞组(n=25)分别为1.242±1.057和0.046±0.076。用Shp-2特异性反义寡核苷酸阻断Shp-2表达后,白血病细胞出现明显凋亡和生长抑制。结论Shp-2在人白血病细胞中呈过度表达状态,其表达水平可能与白血病细胞增殖程度密切相关。

Objective To investigate the effects of Shp-2 tyrosine phosphatase activity on unlimited proliferation of leukemia cells. Methods Shp-2 protein and mRNA were evaluated with Western blot and RT-PCR, respectively. Shp-2 specific antisense was used to block Shp-2 expression in leukemia cells and the effects of down-regulation of Shp-2 on the growth and apoptosis of leukemia cells were determined by clone forming assay and flow cytometry （FCM）. Results Shp-2 protein was overexpressed in most primary leukemia cell samples from various subtypes of leukemias,as compared to normal hematopoietic cells. The mean ratios of Shp-2/β-actin in leukemia samples （n= 36）,normal BM （n= 8） and PBMC samples （n=12） were 1.23 ±0. 74, 0. 163±0. 088 and 0. 034±0. 045, respectively. Likely, high levels of Shp-2 mRNA were also observed in most leukemia cases,and the mean ratios of Shp-2/β-actin in leukemia cases （n= 26） and PBMCs from healthy donors （n= 25） were 1. 242±1. 057 and 0. 046±. 076, respectively. Down-regulation of Shp-2 expression caused remarkbaly apoptosis and inhibition of leukemic cell growth. Conclusions Shp-2 tyrosine phosphatase is overexpressed in most adult leukemia cases ,and its activity positively correlates with proliferative potential of leukemia cells.