Yu Wen-Juan, Rao Qing, Wang Min, Tian Zheng, Xu Zhi-Fang, Wang Jian-Xiang
Institute of Hematology and Blood Diseases Hospital, CAMS and PUMC, Tianjin 300020, China.
Zhonghua Xue Ye Xue Za Zhi. 2007 Oct;28(10):677-80.
To explore the signal transduction pathway in the differentiation and apoptosis of leukemia cells induced by heat shock protein 90 (HSP90) inhibitor 17-Allyl amide-17-demethoxygeldanamycin (17AAG).
Kasumi-1 cells were treated with increasing concentrations or exposure time of 17AAG. The total kit protein (CD117), phosphorylated kit protein and its downstream signaling molecules were measured by Western blot analysis. Mutated kit protein from control and 17AAG-treated Kasumi-1 cells was immunoprecipitated and immunoblotted for associated chaperones.
Total kit protein and kit activity were decreased in 17AAG treated cells, but c-kit mRNA level was not. Total AKT protein and phospho-AKT, as well as phospho-STAT3 were rapidly down-regulated in Kasumi-1 cell after treatment with 17AAG. There was no change in total STAT3 protein. Immunoprecipitation showed that 1 microM 17AAG treatment for 1 hour caused kit associated HSP90 decrease and HSP70 increase.
17AAG-induced apoptosis of Kasumi-1 cells is associated with a decline in Asn822Lys mutated kit protein level and phosphorylated kit, and with a downregulation in its downstream activated signaling molecules involved in proliferation. AKT is a client protein of HSP90. The changes of kit associated HSP90 and HSP70 satisfy the circulation mode of molecular chaperone complex.
探讨热休克蛋白90（HSP90）抑制剂17-烯丙基氨基-17-去甲氧基格尔德霉素（17AAG）诱导白血病细胞分化和凋亡的信号转导途径。
用不同浓度或不同作用时间的17AAG处理Kasumi-1细胞。采用蛋白质印迹分析检测总试剂盒蛋白（CD117）、磷酸化试剂盒蛋白及其下游信号分子。对对照及17AAG处理的Kasumi-1细胞中的突变试剂盒蛋白进行免疫沉淀，并对相关伴侣蛋白进行免疫印迹分析。
17AAG处理的细胞中总试剂盒蛋白和试剂盒活性降低，但c-kit mRNA水平未降低。用17AAG处理Kasumi-1细胞后，总AKT蛋白、磷酸化AKT以及磷酸化STAT3迅速下调。总STAT3蛋白无变化。免疫沉淀显示，1μM 17AAG处理1小时导致与试剂盒相关的HSP90减少，HSP70增加。
17AAG诱导Kasumi-1细胞凋亡与Asn822Lys突变试剂盒蛋白水平和磷酸化试剂盒蛋白的下降有关，与其下游参与增殖的活化信号分子下调有关。AKT是HSP90的客户蛋白。与试剂盒相关的HSP90和HSP70的变化符合分子伴侣复合物的循环模式。
