Viallard V, Lacombe C, Nebot C, Castan I, Trocheris V. Acyl-CoA: cholesterol acyltransferase in HT 29 cell subpopulations. Defect of activity in the undifferentiated cells.
BIOCHIMICA ET BIOPHYSICA ACTA 1991;
1085:265-71. [PMID:
1892896 DOI:
10.1016/0005-2760(91)90103-o]
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Abstract
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.
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