Figure 6.

No role for β-catenin/TCF-dependent gene activity in E-cadherin–mediated inhibition of cell growth. (A) HT29, MCF-7, and SW480/E-cadherin FL cells were transiently transfected with GFP alone or with either β-cat/engrailed (dominant-negative) or VP16/TCF (constitutively active TCF) expression vectors. Isolated transfected cells were identified by GFP expression and proliferation assayed by BrdU incorporation. (B) SW480/E-cadherin FL cells were transfected with siRNAs targeting β-catenin, dominant-negative β-catenin–engrailed or dominant-negative TCF (DN TCF). At 24 h posttransfection, the cells were transfected transiently with either TOPFLASH or FOPFLASH reporter to determine TCF activity. (C) E-cadherin was immunoprecipitated (IP) from detergent lysates of subconfluent MCF-7 or SW480/E-cadherin FL cells treated with (lane 2 and 4) and without (lane 1 and 3) siRNA against β-catenin for 24 h. The total immunoprecipitates and 4% of the supernatant (Sup) were analyzed by western blotting for β-catenin and E-cadherin. Data are expressed as mean ± SEM (*p < 0.05).