AJP - Cell Physiology, Vol 260, Issue 6 C1245-C1252, Copyright © 1991 by American Physiological Society
Expression of Na(+)-coupled sugar transport in HT-29 cells: modulation by glucose
A. Blais
Institut National de la Sante et de la Recherche Medicale U 178, Villejuif, France.
The human colon carcinoma cell line HT-29 adapted to grow in absence of
glucose exhibits a typical enterocytic differentiation. In contrast, cells
grown in glucose always remain undifferentiated. To investigate whether
differentiated HT-29 cells express a Na(+)-dependent sugar transporter,
isotopic tracer flux measurements of a non-metabolizable sugar analogue
methyl alpha-D-glucoside (AMG) were undertaken. AMG accumulation in
confluent monolayer of differentiated HT-29 cells was inhibited by
replacement of sodium, phlorizin, phloretin, and glucose. Kinetic studies
demonstrate the presence of only one Na(+)-dependent phlorizin-sensitive
sugar transporter in differentiated HT-29 cells. Undifferentiated HT-29
cells cultured in the presence of glucose did not show a Na(+)-dependent
AMG accumulation. As previously demonstrated for other markers of the
enterocytic differentiation, this transporter has a growth-related
expression. Moreover, it shares similar properties with the Na(+)-dependent
glucose transport in the human fetal small intestine and colon. To
demonstrate that the expression of the Na(+)-dependent sugar cotransporter
can be modulated by glucose, differentiated HT-29 cells grown in
glucose-free medium were switched to 25 mM glucose. In that condition the
Na(+)-dependent AMG uptake was almost abolished. However, when these cells
were switched back to glucose-free medium, the Na(+)-dependent AMG uptake
was restored, although at a lower level. These experiments show that
differentiated HT-29 cells are a good cellular model to study the
regulation of the Na(+)-dependent sugar transporter.
