Figure 1. PU-H71 interacts with a restricted fraction of Hsp90 that is more abundant in cancer cells.
(a) Sequential immunopurification steps, as indicated by the arrow, with H9010 (a Hsp90-specific antibody) deplete Hsp90 in the MDA-MB-468 cell extract. Lysate, control cell extract. (b) Hsp90 from MDA-MB-468 extracts was isolated through sequential chemical-purification and immunopurification steps. (c) Saturation studies were performed with 131I-PU-H71 in the indicated cells (below). Expression of Hsp90 in the indicated cells was analyzed by western blotting (above). Representative data of four separate repeats are presented. (d) Binding of PU-FITC, presented as mean fluorescence intensity (MFI), to primary AML and CML, CD34+ cord blood cells (CB), or K562 cells pretreated with the indicated doses of PU-H71 for 24 h. TEG-FITC is a nonspecific binding control. (e) Percent viability relative to untreated control for the indicated cells after treatment for 96 h with the indicated doses of PU-H71. Data are presented as means ± s.e.m. (n = 3).