Expression of plasminogen activator inhibitor type 1 (PAI-1) by HT-29di human large bowel carcinoma cells is modulated as a function of epithelial differentiation.
Highly differentiated epithelial populations (36% mucin-producing cells; sixfold increase in alkaline phosphatase activity; development of flat, substrate-adherent, entero-cytic foci) were induced upon in vitro exposure of HT-29di human colon carcinoma cells to sodium butyrate (NaB). 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] (10(-7) M) and the ionophore A23187 (0.5 microM) significantly augmented (two to threefold) NaB-induced HT-29di differentiation, whereas 1,25-(OH)2D3 or A23187 alone were not effective. Induction reflected specific changes in protein abundance, involving, most notably, a differentiation-associated increase in the expression and substrate-deposition of a 47-kDa protein with pI/mw two-dimensional map coordinates and immunochemical properties identical to that of plasminogen activator inhibitor type 1 (PAI-1), a major regulator of the pericellular proteolytic cascade. Culture of HT-29di cells in medium of either high (2.5 mM) or low (0.25 mM) Ca2+ concentration did not affect the incidence of 'spontaneous' differentiation, although NaB-induced goblet cell and enterocytic maturation was Ca(2+)-dependent. The inability of 1,25-(OH)2D3, A23187 or modulated Ca2+ levels alone (i.e., in the absence of NaB) to effect differentiation of HT-29di cells and the Ca(2+)-dependence of the NaB response indicate that NaB and Ca2+ act co-operatively to induce colonic epithelial maturation in vitro.
Higgins
P J
PJ
Department of Microbiology, Immunology and Molecular Genetics (A-68), Albany Medical College, NY 12208.
Lipkin
M
M
D000469:Alkaline Phosphatase / Q000378:metabolism; D002087:Butyrates; D020148:Butyric Acid; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002452:Cell Count / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells; D004912:Erythrocytes / Q000166:cytology; D006801:Humans; D009077:Mucins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism / Q000502:physiology; D017395:Plasminogen Activator Inhibitor 1 / Q000502:physiology*; D011233:Precipitin Tests; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000502:physiology
D002087:Butyrates; D009077:Mucins; D009363:Neoplasm Proteins; D017395:Plasminogen Activator Inhibitor 1; D020148:Butyric Acid; D000469:Alkaline Phosphatase