Convergent effects of growth factors, hormones, and fibronectin are necessary for the enterocyte differentiation of a colon adenocarcinoma cell line (HT29-D4).
The aim of this work was to show in serum-free medium a convergent effect of physiological factors and extracellular matrix proteins on the differentiation process of enterocytes by taking as a model the HT29-D4 clone that has the feature of differentiating when subcultured in fetal bovine serum glucose-free medium. We show that triiodothyronine (T3) as well as insulin promotes limited cell growth and differentiation, whereas fibronectin or bovine serum albumin (BSA) induces cell growth and a low level of differentiation. However, insulin, T3, fibronectin, and BSA together with epidermal growth factor and transferrin promoted satisfactory growth and enterocyte morphology with epithelial electrophysiological properties in HT29-D4 cells. With these factors adequate protein targeting was achieved since cells apically expressed the carcinoembryonic antigen, and basolaterally transferrin and insulin receptors, beta 1 and alpha v beta 6 integrins, talin, vinculin, and focal adhesion kinase (FAK). Talin, vinculin, FAK, and alpha v beta 6 integrin, the fibronectin receptor, were clustered in focal contacts, which agrees with a possible role of fibronectin in final cell growth, the latter process mediating the final phase of differentiation. This level of differentiation can be maintained for a long time. Thus HT29-D4 cells appear to be a suitable model to study the implication of integrins in the differentiation process of human enterocytes.
Rognoni
J B
JB
UPRES-A CNRS 6032, Faculté de Pharmacie, Université Aix-Marseille I et II, France.
Pichard
V
V
Honore
S
S
Rigot
V
V
Lehmann
M
M
Roccabianca
M
M
Carles
G
G
Luis
J
J
Marvaldi
J
J
Briand
C
C
D000230:Adenocarcinoma / Q000473:pathology*; D000818:Animals; D002417:Cattle; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology*; D016895:Culture Media, Serum-Free; D005353:Fibronectins / Q000494:pharmacology*; D019084:Fluorescent Antibody Technique, Indirect; D006133:Growth Substances / Q000494:pharmacology*; D019073:HT29 Cells; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000473:pathology; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D016895:Culture Media, Serum-Free; D005353:Fibronectins; D006133:Growth Substances; D006728:Hormones; D007328:Insulin; D014284:Triiodothyronine; D012710:Serum Albumin, Bovine