As2O3对K562细胞BCR/ABL蛋白酪氨酸磷酸化的影响

目的　进一步阐明Ａｓ２Ｏ３ 诱导Ｋ５６２ 细胞凋亡和抑制其生长的可能机制，为Ａｓ２Ｏ３ 在临床上的应用提供理论依据。方法　采用免疫沉淀、Ｗｅｓｔｅｒｎ ｂｌｏｔ、生物化学及免疫荧光等方法研究了Ａｓ２Ｏ３对ＢＣＲ／ＡＢＬ蛋白酪氨酸磷酸化及其所介导的信号途径和某些凋亡相关蛋白表达的影响。结果　１μｍｏｌ／ＬＡｓ２Ｏ３ 使细胞内多种蛋白酪氨酸磷酸化减少，而且ＢＣＲ／ＡＢＬ蛋白自身酪氨酸磷酸化亦减少，但０ ．１ μｍｏｌ／ＬＡｓ２Ｏ３ 对蛋白酪氨酸磷酸化的影响不明显；Ａｓ２Ｏ３ 对蛋白酪氨酸磷酸酶（ＰＴＰ） 活性未见明显影响；Ａｓ２Ｏ３ 下调ＪＡＫ２ 蛋白的表达，但对ＳＴＡＴ１ 和ＳＴＡＴ２ 蛋白的表达以及ＳＴＡＴ１ 蛋白酪氨酸磷酸化无影响；Ａｓ２Ｏ３ 亦不影响凋亡相关蛋白Ｂｃｌ２、ＢｃｌｘＬ／Ｓ、Ｂａｘ、ＩＣＨ１Ｌ、ｐ５３、ＰＡＲＰ的表达，Ａｓ２Ｏ３ 亦使Ｋ５６２ 细胞的ＰＭＬ蛋白降解。结论　Ａｓ２Ｏ３ 可能通过减少细胞内某些蛋白，尤其是ＢＣＲ／ＡＢＬ蛋白酪氨酸磷酸化和（ 或）下调ＪＡＫ２ 蛋白的表达而干扰ＢＣＲ／ＡＢＬ致癌信号的传导，引起Ｋ５６２ 细胞凋亡和抑制其生长。

Effects of As_2O_3 on the BCR/ABL protein tyrosine phosphorylation in K562 cells

OBJECTIVE: To explore the mechanisms of As2O3 inducing apoptosis and growth inhibition in K562 cells and provide theoretical basis for clinical application. METHODS: The effects of As2O3 on BCR/ABL protein tyrosine phosphorylation(PTP) and its signal transduction as well as the expression of apoptosis-related genes were studied by means of immunoprecipitation, Western blot, biochemical method and immunofluorescence. RESULTS: Tyrosine phosphorylation of several cellular proteins especially BCR/ABL protein was decreased by 1 mumol/L As2O3, but not by 0.1 mumol/L As2O3. As2O3 had no effect on PTP activity, downregulated the expression of JAK2 protein, but did not affect the expressions of STAT1 and STAT2 proteins and the STAT1 protein tyrosine phosphorylation. As2O3 had no effect on the expression of the apoptosis-related genes like Bcl-2, Bcl-xL/S, Bax, ICH-1L, p53, PARP, either, but downregulated PML protein expression in K562 cells. CONCLUSION: As2O3 might induce K562 cell apoptosis and inhibit its growth by reducing tyrosine phosphorylation of cellular proteins especially BCR/ABL protein and/or by downregulating JAK2 protein expression to interfere with the BCR/ABL protein signal transduction.