Fig 2.

Repression of p300 influences WNT signaling hyperactivation by butyrate. (A) Confirmation of activity of p300 siRNA previously utilized to downregulate p300, but not CBP, expression ³⁰. (B) 15 pmoles/well control (mock, M) or p300 siRNA (p300si) were cotransfected into HCT-116 cells (96-well plate) along with the TOPFlash or FOPFlash vectors and pRLTK control. Cell media was changed after 5 hours, and after another 24 hr, cells were mock treated (M) or treated with 5 mM butyrate (B) for another 17 hr. Data are from three separate experiments. Bars, SDs. * = statistical significance. (C) SW620 cells were treated as in (B). Data are from three separate experiments. Bars, SDs. * = statistical significance. (D) HCT-116 cells were transfected with Ctl or p300 siRNA, mock treated or treated with 5 mM butyrate for 24 hr, and proliferation assayed as described in Materials and Methods. Data are from four separate experiments. Bars, SDs. (E) SW620 cells were treated with p300 siRNA and butyrate as in (D). Data are from four separate experiments. Bars, SDs.