Mesd C-terminal region peptide blocks Wnt1-induced Wnt/β-catenin signaling in prostate cancer PC-3 and breast cancer HS578T cells.

<p>(A) PC-3 and HT578T cells in 24-well plates were transiently transfected with the Wnt1 plasmid along with the Super8XTOPFlash luciferase construct and β-galactosidase-expressing vector in each well. After 24 h incubation, cells were treated with mouse Mesd (mMesd), human Mesd peptide hMesd (160–197) or control peptide at the indicated concentrations. The luciferase activity was then measured 24 h later with normalization to the activity of the β-galactosidase. Values are the average of triple determinations with the s.d. indicated by error bars. <i>**P</i><0.01 compared to the control cells without Mesd or Mesd peptide treatment. (B) PC-3 and HS578T cells in 6-well plates were transiently transfected with Wnt1 plasmid or the corresponding control vector. After being incubated for 24 h, cells were treated with mMesd, hMesd (160–197) or control peptide at the indicated concentrations for 24 h. The levels of cytosolic free β-catenin, and total cellular Wnt1, β-catenin, LRP6, Axin2, cyclin D1 and phosphorylated LRP6 were then analyzed by Western blotting. Samples were also probed with the anti-actin antibody to verify equal loading.