title: Dihydrofolate reductase gene amplification-associated shift of differentiation in methotrexate-adapted HT-29 cells.
abstract: 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.
authors.affiliation: Unité de Recherches sur la Différenciation Cellulaire Intestinale, INSERM U178, Villejuif, France.
authors.forename: T
authors.initials: T
authors.lastname: Lesuffleur
authors.forename: A
authors.initials: A
authors.lastname: Barbat
authors.forename: C
authors.initials: C
authors.lastname: Luccioni
authors.forename: J
authors.initials: J
authors.lastname: Beaumatin
authors.forename: M
authors.initials: M
authors.lastname: Clair
authors.forename: A
authors.initials: A
authors.lastname: Kornowski
authors.forename: E
authors.initials: E
authors.lastname: Dussaulx
authors.forename: B
authors.initials: B
authors.lastname: Dutrillaux
authors.forename: A
authors.initials: A
authors.lastname: Zweibaum
mesh_terms: 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
chemical_list: D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate