ROLE OF CHOLESTEROL-SYNTHESIS AND ESTERIFICATION IN THE GROWTH OF CEMAND MOLT4 LYMPHOBLASTIC CELLS

CEM and MOLT4 are human T-cell lines isolated from patients with acute cell leukaemia. In culture they show important differences in cholest erol metabolism, CEM being less efficient at synthesizing cholesterol and having a lower activity of 3-hydroxy-3-methylglutaryl-CoA (HMGCoA) reductase. To investigate further the relationship between regulation of intracellular cholesterol metabolism at various steps and rate of cell growth, cholesterol synthesis, esterification and efflux were eva luated in CEM and MOLT4 cells at different times during exponential an d stationary growth in vitro. It was shown that, although CEM cells ha ve a lower rate of cholesterol synthesis, they grow at a faster rate t han MOLT4 cells. However, CEM cells exhibit an increased capacity to e sterify cholesterol associated with a decreased efflux of newly synthe sized cholesterol into the medium. These results provide evidence for an association between the capability to synthesize and retain cell ch olesterol esters and the growth rate potential.