Fig 4.

Effect of 17-AAG on STAT and Rac1 activation, as well as E. coli invasion of HBMEC. (A) To examine the effect of 17-AAG (a geldanomycin and HSP90/STAT3 inhibitor) on E. coli adhesion to and invasion of HBMEC, HBMEC were treated with the inhibitor or vehicle control and then examined for E. coli adhesion and invasion. *, P < 0.05 compared to vehicle control. (B and C) HBMEC treated with 17-AAG or vehicle control were incubated with E. coli for various time points, and the lysates were analyzed for either p-STAT3 (Bi) or Rac1 (Bii) activation by Western blotting. Band intensities were estimated densitometrically and are expressed as the fold increase in the pSTAT3/STAT3 (Ci) or GTP-Rac1/total Rac1 (Cii) ratio.