Liu Xue-guang, Guo Ye, Yan Zuo-qin, Guo Mu-yi, Zhang Zhi-gang, Guo Chang-an
Department of Pathology, Fudan University, Shanghai 200032, China.
Zhonghua Zhong Liu Za Zhi. 2011 May;33(5):340-4.
To investigate the expression of heat shock protein 90 (HSP90) on the cell surface of highly invasive human prostate cancer cells PC3 and its possible molecular mechanisms of its effect on cell invasion through analyzing FAK/Src signaling pathway.
The expression of cell surface HSP90 on PC3 cells was studied by immunofluorescence staining and surface biotinylation assay respectively. A specific HSP90 antibody was used to inhibit the cell surface HSP90. In vitro cell invasion was assessed by modified Boyden chambers. Phosphorylated FAK on tyr 397, 576, 577 and 925, and phosphorylated c-Src on tyr 416 were examined by Western blot assay. The association between FAK and c-Src was analyzed by immunoprecipitation. The effects of FAK knockdown by siRNA or Src kinases inhibitor PP2, with or without anti-HSP90 antibody, on PC3 cell invasion were also evaluated.
A pool of HSP90 was detected on the cell surface of PC3 cells. A specific HSP90 antibody significantly retarded tumor cell invasion. Concomitant with this finding, targeting cell surface HSP90 significantly inhibited the phosphorylations of FAK and c-Src, and also the interactions between FAK and c-Src. FAK knockdown or PP2 dramatically suppressed cell invasion, however, anti-HSP90 antibody didn't further inhibit cell invasion.
Cell surface HSP90 promotes human prostate cancer cell invasion through a FAK/c-Src signaling, with may be a novel therapeutic target against metastatic tumors.
通过分析黏着斑激酶（FAK）/原癌基因酪氨酸蛋白激酶（Src）信号通路，研究热休克蛋白90（HSP90）在高侵袭性人前列腺癌细胞PC3细胞表面的表达及其影响细胞侵袭的可能分子机制。
分别采用免疫荧光染色和表面生物素化分析研究PC3细胞表面HSP90的表达。使用特异性HSP90抗体抑制细胞表面HSP90。采用改良的Boyden小室评估体外细胞侵袭。通过蛋白质免疫印迹法检测酪氨酸397、576、577和925位点磷酸化的FAK以及酪氨酸416位点磷酸化的c-Src。通过免疫沉淀分析FAK与c-Src之间的关联。还评估了小干扰RNA（siRNA）敲低FAK或Src激酶抑制剂PP2（有无抗HSP90抗体）对PC3细胞侵袭的影响。
在PC3细胞表面检测到一批HSP90。特异性HSP90抗体显著抑制肿瘤细胞侵袭。与此发现一致，靶向细胞表面HSP90显著抑制FAK和c-Src的磷酸化，以及FAK与c-Src之间的相互作用。敲低FAK或使用PP2可显著抑制细胞侵袭，然而，抗HSP90抗体并未进一步抑制细胞侵袭。
细胞表面HSP90通过FAK/c-Src信号促进人前列腺癌细胞侵袭，这可能是转移性肿瘤的一个新的治疗靶点。
