Accumulation of cholesterol inside HepG2 cells in response to 1.25 uM U18666A. HepG2 cells were seeded in a 96-well plate at a density of 3 X 104 cells/well and cultured overnight. The next day, cells were treated with DMSO (vehicle) or 1.25 uM U18666A for 48 hours. Panel A : Cells treated with DMSO alone demonstrate that majority of cholesterol is localized on the plasma membrane. Panel B : U18666A treatment for 48 hours induces intracellular accumulation of cholesterol droplets, indicating blockage of intracellular cholesterol transport.