Dihydrofolate reductase gene amplification-associated shift of differentiation in methotrexate-adapted HT-29 cells.
Postconfluent cultures of HT-29 cells form a heterogeneous multilayer of which greater than 95% of the cells are undifferentiated. In contrast, when stably adapted to normally lethal concentrations of methotrexate (10(-6)-10(-5) M), they form a monolayer of gobletlike cells (Lesuffleur et al., 1990) which secrete large quantities of mucins and display a discrete brush border with the presence of villin, dipeptidylpeptidase-IV, and carcinoembryonic antigen. When adapted to even higher concentrations of methotrexate (10(-4) and 10(-3) M) there is a shift in the pattern of differentiation from gobletlike to dome-forming absorptive-like cells. These cells still display an apical brush border which expresses villin and dipeptidylpeptidase-IV, but no longer express significant levels of mucins and carcinoembryonic antigen. This shift of differentiation coincides with a sudden amplification of the gene coding for dihydrofolate reductase and an increased activity of the enzyme.
Lesuffleur
T
T
Unité de Recherches sur la Différenciation Cellulaire Intestinale, INSERM U178, Villejuif, France.
Barbat
A
A
Luccioni
C
C
Beaumatin
J
J
Clair
M
M
Kornowski
A
A
Dussaulx
E
E
Dutrillaux
B
B
Zweibaum
A
A
D015139:Blotting, Southern; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D005784:Gene Amplification; D007700:Kinetics; D008727:Methotrexate / Q000494:pharmacology*; D008854:Microscopy, Electron; D010641:Phenotype; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics* / Q000378:metabolism
D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate