β-Catenin is constitutively activated in leukemic stem-like cells overexpressing VE-cadherin during LTCC. (A) Dual-luciferase reporter (DLR) assays of Sup-B15 LTMC (Med) or LTCC cells (S10 or PatX) transiently cotransfected with phRL-TOP1 or phRL-TOP2 Renilla luciferase reporters with an internal control pGL4.13-CMV-Luc2 firefly luciferase reporter. Experimental Renilla luciferase activity was normalized to that of control firefly luciferase and is shown as relative luciferase units (RLUs). Data were presented as mean plus or minus SD (n = 3). (B) DLR assays of cell lysates from Sup-B15 cells transduced with wild-type or the 2 truncated forms of VE-cadherin. Data were presented as mean plus or minus SD (n = 3). The * denotes significant differences compared with Vect controls (P < .01) based on the Student t test. (C) Sup-B15 cells transfected with 100 nM VE-cadherin siRNA for 8 to 72 hours (top) or at a concentration of 50 to 200 nM for 24 hours (bottom). Data are shown as the mean plus or minus SD (n = 3). (D) Confocal micrographs of LTMC or LTCC Sup-B15 cells stained with anti-active β-catenin antibody and were acquired using a 63×/1.2 water C-Apochromat objective. Cell nuclei were counterstained with SYTOX Green. The photograph of LTMC was made from cytospin preparation, and the photograph of LTCC Sup-B15 cells was taken from a portion of 1 hematopoietic cord.