Figure 3.

Effects of mβCD and filipin treatments on TF-VIIa—induced PI hydrolysis. A, MDA-MB-231 cells loaded with myo-[2-³H] inositol were treated with either varying concentrations of mβCD or filipin, for 1 hour and 15 minutes, respectively. Thereafter, the cells were exposed to VIIa (10 nM) for 2 hours and the total ³H-inositol phosphates released were quantified (n=4 to 6 ±SEM). B, Myo-[2-³H] inositol-loaded MDA-MB-231 cells were first treated for 30 minutes at 37°C with mβCD (10 mmol/L) to deplete cholesterol. After washing the cells, cholesterol was reintroduced to the cells by incubating the cholesterol-depleted cells with varying concentrations of cholesterol in mβCD (10 mmol/L) for 30 minutes. After cholesterol loading, the cells were washed and exposed to VIIa (10 nM) for 2 hours and the total ³H-inositol phosphates released were quantified (n=3 ±SEM). *Significantly (P<0.05) differs from the control cells that are exposed to VIIa (A) or cholesterol-depleted cells (mβCD +0 cholesterol; B). NT, not treated with either mβCD or cholesterol.