ETPs disrupt the endogenous HIF-1α/p300 complex in cells. PC3 cells were cultured under normoxia or hypoxia (CoCl2) in the presence or absence of the indicated concentrations of gliotoxin and chaetocin. After 18 h, co-immunoprecipitations were performed from the cell lysates using a p300 mouse monoclonal antibody and Protein A/G Agarose. Bound proteins were eluted with SDS buffer followed by immunoblot analysis of the lysates (left panels) and immune complexes (right panels) with antibodies recognizing p300 and HIF-1α. A, Treatment with 25 nM and 500 nM gliotoxin (GLIO). B, Treatment with 5 nM and 100 nM chaetocin (CTM) (n = 3 for all).