Knockdown of c-Myc or E2F1 attenuates β-catenin-dependent induction of Bcl-2 promoter activity and Bcl-2 protein expression. HEK293 cells were transfected with Bcl-2-P1, in the presence and absence of exogenous β-catenin, plus c-Myc siRNA or E2F1 siRNA. Luciferase and β-Gal activities were assayed 48 h post-transfection. Luciferase activity was normalized to β-Gal activity to obtain the Relative Luciferase Activity. Data, mean±s.d., n=3; **P<0.01. Corresponding whole cell lysates were immunoblotted for β-catenin, c-Myc, E2F1, β-actin, Bcl-2 and cleaved caspase 3, as indicated. Arrows, 19-kDa and 17-kDa bands indicative of cleaved (active) caspase 3.