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Fig. 3. Effects of cholesterol and lovastatin on the TGF-
1-stimulated luciferase activity (A) and TGF-1-induced growth inhibition (B) in Mv1Lu cells. (A) Cells stably expressing a luciferase reporter gene were treated with increasing concentrations (as indicated) of cholesterol at 37°C for 1 hour (a) or with 1 µM lovastatin at 37°C for 16 hours ± cholesterol (20 µg/ml) at 37°C for 1 hour (b) and then further incubated with 50 pM TGF-1 for 6 hours. The luciferase activity of the cell lysates (20 µg protein) was determined and expressed as arbitrary units (A.U.). The luciferase activity in cells treated with TGF-1 only was taken as 100% (a). The data was obtained from three or four independent analyses. *Significantly lower or higher than that in cells treated with TGF-1 only: P<0.001. (B) Cells were incubated with 0.0625 and 0.125 pM TGF-1 in the presence of increasing concentrations of cholesterol, as indicated. Cell growth was then determined by measurement of [3H-methyl]thymidine incorporation into cellular DNA. The [3H-methyl]thymidine incorporation in cells treated with vehicle only was taken as 100%. TGF-1 at 0.0625 and 0.125 pM inhibited DNA synthesis by 
30% and 40%, respectively. The degree (%) of cholesterol-mediated reversal of TGF-1 growth inhibition was estimated by the equation: % reversal=[1–(T1–T2/T3–T4)]x100, where T1 is the thymidine incorporation in cells treated with cholesterol alone; T2, the thymidine incorporation in cells treated with cholesterol plus TGF-1; T3, the thymidine incorporation in cells treated with vehicle only and T4, the thymidine incorporation in cells treated with TGF-1 alone. The experiments were carried out in triplicate.
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