Expression of dominant negative TCF attenuates Bzb-induced TCF transcriptional activity in MSCs. (A) MSCs were seeded at 5 × 104 cells/mL in 10-cm tissue culture plates and cotransfected with 0.5 mg/mL of empty vector, dnTCF1, or dnTCF4 plasmid DNAs. Total protein (50 mg) was isolated and immunoblotted with anti-TCF (left panel) or anti-HA (right panel) antibodies to measure the expression of dnTCF1 (left panel) and dnTCF4 (right panel) proteins. C2C12 (B), C3H10T1/2 (C), MG63 (D), and Saos-2 (E,F) cells cultured in 12-well plates in DMEM with 10% FBS were cotransfected with 0.5 mg/mL of empty vector, dnTCF1, dnTCF4 plasmid DNA plus TOPflash plasmid DNA. After 48 hours of incubation, the cells were incubated in media in the absence or presence of 6.25 nM (B), 12.5 nM (C,D), or 100 nM (E) Bzb, or 65 nM of MG132 (F) and cells lysed for luciferase quantification. The data represent mean plus or minus SD. **P < .01, ***P < .001 vs controls.
