The Wnt inhibitor DKK1 abolishes ERK and PI3K signalling restored by N-cadherin blockade.

<p>(A) Control (Flag) cells were transiently transfected with empty vector (EV) or DKK1, or treated with the Wnt antagonist Sfrp1 in the presence or absence of Wnt3a CM and TCF/TOP transcriptional activity was determined. Means are +/− SD. Values that are significantly different are indicated (a, <i>P</i><0.05 vs EV -Wnt treated cells; b, <i>P</i><0.05 vs EV Wnt treated cells). (B) Flag and N-Cad cells transiently transfected with empty vector (EV) or DKK1 were treated with the bloking N-cadherin antibody (N-Cad Ab) or control antibody (IgG) for 24 hours and DKK1 levels and ERK and PI3K signalling were analysed by Western-blot. GAPDH was used as loading control. (C) Flag and N-Cad overexpressing cells transfected with empty vector (EV) or DKK1 were treated with the N-cadherin antibody for 24 hours to restore ERK and PI3K signalling or with control antibody (IgG), and cell replication was determined (a, <i>P</i><0.05 vs EV Flag cells; b, <i>P</i><0.05 vs N-Cad Ab treated EV Flag cells; c, <i>P</i><0.05 vs N-Cad Ab treated EV N-Cad cells).