Figure 4
From: Differential PKA activation and AKAP association determines cell fate in cancer cells
OSI-906 regulates XIAP in a TGFβ/PKA dependent manner. FET cells treated with OSI-906 (1 μM) showed effective downregulation of XIAP. This observed downregulation is PKA dependent as downregulation of XIAP was abrogated in FET cells treated with PKA inhibitor H89 (15 μM) (A). OSI-906 mediated XIAP downregulation is dependent on Smad3 as determined by shRNA knockdown of Smad3 in FET cells (termed as FETS3KD). FETS3KD cells treated with OSI-906 showed no change in XIAP expression. However, FET Scr cells showed XIAP downregulation following treatment with OSI-906 (B). FET cells treated with OSI-906 effectively dissociated XIAP from Survivin as determined by immunoprecipitation (IP) assay (C). OSI-906 mediated XIAP/Survivin dissociation is PKA dependent as dissociation was abrogated when FET cells were treated with H89 and/or pretreated with H89 prior to OSI-906 treatment. Relative quantification of the IP has been performed showing reduced interaction between survivin/XIAP following OSI-906 treatments (D).