Figure 4.

Luteolin disrupted the binding of HSP-90 to STAT3. (a) Lysates of SGC7901/DDP cells treated with luteolin or control were immunoprecipitated with anti-STAT3 antibody or control rabbit IgG, and the immunopellets were detected by immunoblot analysis with anti-SHP-1 and anti-STAT3 antibody. Cell lysates were then immunoprecipitated with anti-SHP-1 antibody or control rabbit IgG, and the immunopellets were detected by immunoblot analysis with the anti-STAT3 antibody and anti-SHP-1 antibody. (b) The lysates of above-treated cells were immunoprecipitated and blotted with indicated antibodies. (c) The lysates of luteolin-treated cells were immunoprecipitated with STAT3 antibody and blotted with SHP-1 and HSP-90 antibodies at same time. (d) SGC7901/DDP cells were transfected with HSP-90 siRNA or controlled siRNA. Western blotting with indicated antibodies was performed. (e) Total RNA of the above transfected cells of the cells was extracted and a QPCR method was adopted to test the transcription level of indicated genes. The result was obtained of three independent experiments, *P<0.05. (f) SGC7901/DDP cells were transfected with HSP-90 siRNA or control siRNA and then the cells were immunoprecipitated and blotted with indicated antibodies. (g) The model of the luteolin regulation of STAT3 phosphorylation