FIG 4.

YM-53601 inhibits de novo synthesis of cholesterol and cholesteryl esters. (A to C) Huh-7.5.1-8 cells were pretreated with 1 μM YM-53601 (white bars) or its vehicle, DMSO (black bars), in serum-free medium for 24 h. The cells were subsequently labeled using [³H]acetate in the same medium as for the pretreatment for the indicated periods of time. The lipid fractions were extracted from the cells and analyzed by TLC. The incorporation of [³H]acetate into cholesterol (A), cholesteryl esters (B), and triglycerides (C) was quantified and expressed as photostimulated luminescence (PSL) values per μg cellular protein. (D and E) Huh-7.5.1-8 cells were treated with 1 μM YM-53601 (white bars) or DMSO (black bars) for 7 days in serum-free medium. The lipid fraction was extracted from the cells, and the contents of cholesterol (D) and cholesteryl esters (E) were determined. The values for cholesteryl esters (E) are expressed as the cholesterol content in the fraction. Data are means ± SD for triplicate samples from one representative experiment. Similar results were obtained in two independent experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001.