Role of PTEN in CRP-induced downregulation of Akt/mTOR/p70S6K pathway.

<p>(A) H9c2 cardiac myocytes were treated with indicated concentration of CRP in 0.5% FBS for 24 hours. Expression levels of PTEN were determined by immunoblot analysis and RT-PCR, respectively. (B) H9c2 cells transfected with 20 nM of PTEN siRNA were incubated 50 µg/ml of CRP in 0.5% FBS for 24 hours and then treated 10% FBS for 1 hour. Cells were harvested and analyzed for PTEN, Akt, mTOR and p70S6K signaling pathway by immunoblot assay. (C) PTEN siRNA-transfected cells were incubated 50 µg/ml of CRP in 0.5% FBS for 24 hours and then treated 10% FBS for 24 hours. Protein levels of PTEN or survivin were analyzed by immunoblot assay. (D) H9c2 cells pretreated with PTEN inhibitor (BpV, 5 µM) for 1 hour were incubated with 50 µg/ml of CRP in 0.5% FBS for 24 hours and then treated 10% FBS for 1 hour. Cells were harvested and analyzed for PTEN, Akt, mTOR and p70S6K signaling pathway by immunoblot assay. (E) PTEN inhibitor-pretreated cells were incubated 50 µg/ml of CRP in 0.5% FBS for 24 hours and then treated 10% FBS for 24 hours. Protein levels of PTEN or survivin were analyzed by immunoblot assay.