β-catenin缺失抑制bcr—abl所致白血病细胞中Stat-5α磷酸化

Loss of β-catenin inhibits Stat-5α phosphorylation in bcr-abl induced leukemia cells

目的研究经bcr—abl诱导形成的白血病细胞中β—catenin缺失对Stat-5α蛋白磷酸化水平的影响。方法利用已经建立的特异性骨髓造血系统β-catenin基因敲除小鼠，分离其骨髓细胞，应用逆病毒感染方法将外源性bcr-abl基因片段导入β—catenin缺失的骨髓细胞内，免疫荧光和Western blotting方法检测Star-5α蛋白磷酸化水平，应用real—time PCR及Western blotting分别检测B．catenin缺失细胞及对照细胞bcr．abl转录及蛋白表达。结果与对照组相比，β—catenin缺失的白血病细胞Stat-5α磷酸化水平明显降低，而Stat-5α总蛋白量变化不明显；Western blotting结果显示β—catenin缺失的慢性髓细胞白血病（CML）细胞中酪氨酸磷酸化总水平及bcr—abl蛋白表达明显降低，而B—catenin缺失的急性淋巴细胞白血病（ALL）细胞中酪氨酸磷酸化总水平及bcr—abl蛋白表达无明显改变。结论bcr-abl诱导形成的白血病转化细胞中，B—catenin缺失抑制bcr—abl蛋白表达及Stat-5α磷酸化。

Objective To investigate the influence of β-catenin gene deletion on Stat-Sα phosphorylation in bcr-abl induced leukemia cells. Methods The established conditonal hcmatopoitic β-catenin knockout mice were used to isolate bone marrow cells. Exogenous bcr-abl fusion gene was transduced to these bone marrow cells by retroviral infection with intent to transfom them to leukemia cells. Immunofluorescence was performed to detect the pbospborylation status of Stat-Sα in both β-catenin deletion cells and control cells, bcr-abl transcription and protein levels were evaluated with real-time PCR and western blotting. Results Phosphorylation of Stat-Sα was reduced significantly in β-catenin deletion leukemia cells on comparison with control cells despite that total Stat-Sα protein showed no obvious changes. Total tyrosine phosphorylation and bcr-abl protein expression were reduced in bcr-abl induced β-catenin deletion CML ceils, on the contrary, both of the reduction were not seen in bcr-abl induced β-catenin deletion ALL cells. Conclusion Loss of β-catenin inhibits both Stat-5α phosphorylationin and bcr-abl expression in bcr-abl induced leukemia cells.