Acyl-CoA: cholesterol acyltransferase in HT 29 cell subpopulations. Defect of activity in the undifferentiated cells.
The ACAT activity was studied on different subpopulations deriving from HT29 cells, a human colon carcinoma cell line. Grown on standard medium (25 mM glucose), about 95% of these cells are undifferentiated (G + cells). From this heterogeneous population, differentiated cells were selected by glucose deprivation and grown either on medium without glucose (G - cells) or in standard medium containing 25 mM glucose (G-Rev cells). The G- and G-Rev cells have the features of differentiated small intestine cells. The two types of differentiated cells (G- and G-Rev) exhibited similar ACAT activities and the kinetic characteristics of the enzyme were also similar. A time-course study showed increasing activity during the exponential phase and a decrease just after confluency. It was possible to stimulate the enzyme by micellar or lipoprotein cholesterol. In contrast, the ACAT activity was hardly detectable in undifferentiated G + cells. In addition, all the experimental conditions known to stimulate ACAT activity, and confirmed in the differentiated HT29 cells, were inefficient in the undifferentiated G + cells. Therefore, the different models derived from HT29 cells provide the opportunity to study cholesterol esterification as well as the consequences of its aberrances in intestinal cells.
Viallard
V
V
INSERM U 317, Institut de Physiologie, Toulouse, France.
Lacombe
C
C
Nebot
C
C
Castan
I
I
Trocheris
V
V
D000230:Adenocarcinoma; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D002788:Cholesterol Esters / Q000378:metabolism; D003106:Colon / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D050356:Lipid Metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D002785:Sterol O-Acyltransferase / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D002788:Cholesterol Esters; D008077:Lipoproteins, LDL; C014409:cholesteryl oleate; D002784:Cholesterol; D002785:Sterol O-Acyltransferase