Figure 2. MUC16C promotes β-catenin-dependent transcriptional activity through enhanced cytosol-nucleus transportation.

A. MUC16C increases the protein level of β-catenin. SKOV-3 cells were transfected with different amount of pcDNA3.3-HA-MUC16C vectors (0, 3 and 6 μg). At 24 h post-transfection, total cell lysates were harvested and subjected to Western blot with indicated antibodies. B. MUC16C enhances the cytosol-nucleus transportation of β-catenin. SKOV-3 cells were transfected with different amount of pcDNA3.3-HA-MUC16C vectors (0 and 3 μg). At 72 h post-transfection, cells were harvested and subjected to nuclear/cytosol fractionation, followed by Western blot with rabbit anti-β-catenin, mouse anti-HA, goat anti-Lamin B and rabbit anti-β-tubulin antibodies respectively. MUC16C activates β-catenin-dependent TOP/FOP luciferase reporter (C) and LEF1 reporter (D). HEK293T cells were transfected with the expression vectors of MYC-β-catenin and HA-MUC16C alone or in combination, together with pRL-TK and TOP/FOP luciferase reporter C. or pGL3-fos-7LEF-luciferase/pCG-LEF1 D. At 24 h post-transfection, luciferase activities were determined, and the results are presented as mean±SD of three independent experiments. The protein levels of ectopically expressed β-catenin and MUC16C were analyzed by Western blot. E. In ovary cancer cell lines SKOV-3 and OVCAR-3, the protein levels of MUC16 are closely correlated with that of β-catenin. Protein levels were determined by using Western blot. F. Wnt signaling is significantly activated in OVCAR-3 cells rather than in SKOV-3 cells. SKOV-3 and OVCAR-3 cells transfected with or without HA-MUC16C, together with TOP/FOP luciferase reporter were determined for relative luciferase activities. ***P<0.0001, student's T-test.