Ectopic expression of LRP6 activated the Wnt/β-catenin pathway.

<p>(A) Schematic diagram showing the structural domains of Myc-tagged full length form of LRP6 (myc-FL LRP6) and the constitutively active form (myc-CA LRP6). (B) Western blotting. Myc-FL LRP6 and myc-CA LRP6 were transiently overexpressed in BEL-7402 HCC cell line and human embryonic kidney cell HEK293T cells. The protein level of β-catenin was increased in both BEL-7402 HCC cell line and HEK293T cells. (C) TOP/FOP luciferase reporter assay. Expression of myc-FL LRP6 led to an activation of TCF/β-catenin reporter up to ∼40-fold (without Wnt3a treatment) and ∼120-fold (with Wnt3a treatment), respectively, as compared with the vector control. The fold of induction in myc-CA LRP6 cells reached ∼150-fold even without Wnt3a treatment. (D) Similar results were also observed in HEK293T cells.