中文摘要：

目的 研究新生霉素（novobiocin．NB）对HL-60／Bcr-Abl细胞的作用，并探讨该作用是否与Bcr-Abl水平和热休克蛋白90（Hsp90）分子伴侣的功能有关。方法 用蛋白免疫印迹法检测Bcr—Abl的含量，采用免疫共沉淀的方法研究Hsp90分子伴侣的功能。先将Bcr—Abl与其分子伴侣共沉淀下来，然后用免疫印迹法检测沉淀物中与Bcr-Abl结合的Hsp90和Hsp70含量变化。应用蛋白酶体抑制剂ALLnL研究Bcr—Abl降解的途径。结果 NB能降低HL-60／Bcr-Abl细胞中Bcr—Abl的蛋白水平，NB使Bcr—Abl与Hsp90和Hsp70的结合减少，促进蛋白酶体降解Bcr-Abl蛋白，ALLnL处理后NP-40insoluble部分Bcr—Abl蛋白水平提高。结论 该研究证明NB通过干扰Hsp90伴侣功能，减少Bcr-Abl与Hsp90和辅伴侣的结合，从而促进蛋白酶体降解Bcr—Abl蛋白，最终抑制HL-60／Bcr—Abl细胞增殖。

英文摘要：

Aim In an effort to confirm the effects of NB on Bcr-Abl expressing HL-60/Bcr-Abl cells, and the relationship between these effects and the molecular chaperone functions of heat shock protein 90 （Hsp90）. Methods The amounts of Bcr-Abl protein were tested by Western blot. Molecular chaperone functions of Hsp90 were measured by coimmunoprecipitation. Co-immunoprecipitation of Bcr-Abl and its molecular chaperones, the immunoprecipitate was then subjected to Western blot analysis with anti-Abl, antiHsp90, or anti-Hsp70 mAb. Proteasome inhibitor ALLnL was used to determine the down-regulation pathway of Bcr-Abl. Results An exposure of HL-60/ Bcr-Abl cells to NB produced down-regulation of intra-cellular Bcr-Abl protein levels. By binding and inhibi- ting Hsp90, NB treatment decreased the binding of Bcr-Abl with Hsp90 and Hsp70 and induced the proteasomal degradation of Bcr-Abl, because cotreatment with proteasome inhibitor ALLnL increased Bcr-Abl levels in NP40-insoluble fraction. Conclusions These studies demonstrate for the first time the activity of NB against HL-60/Bcr-Abl cells and suggest that destruction of Hsp90 chaperon function, resulting in disruption the combination of Bcr-Abl with Hsp90 and cochaperons, may be an important mechanism of NB-media- ted effects on HL-60/Bcr-Abl cells.