Altered morphology in cultured rat intestinal epithelial IEC-6 cells is associated with alkaline phosphatase expression.
Non-transformed, rat intestinal epithelial cells (IEC-6), and human intestinal colonic carcinoma cells (CACO-2) have both been used to study processes of epithelial cell differentiation. However, only CACO-2 cells have been described as spontaneously expressing phenotypic changes of differentiation in culture. We report here that when IEC-6 cells are grown in post-confluent culture, they develop structural changes similar to those seen in cells induced to differentiate by culture on Englebreth-Holm-Swarm (EHS) extracellular matrix proteins. Correlated with this morphological change is loss of nuclear localization of c-myc protein and development of cell surface alkaline phosphatase (ALP) enzymatic activity. Messenger RNAs for liver and intestinal isoforms of ALP were expressed in both pre- and post-confluent cells. Inhibition of ALP activity in post-confluent cells by levamisole indicated the expressed ALP activity to be of the liver isoform. We suggest the expression of ALP activity, which occurs concomitantly with morphological alterations in post-confluent IEC-6 cells, represents increased expression and localization to the cell surface of the liver isoform of ALP. Cultured IEC-6 cells may provide a non-transformed, in vitro alternative to CACO-2 cells for study of epithelial cell differentiation.
Wood
S R
SR
Department of Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Box 8334, Pocatello, ID 83209, USA.
Zhao
Q
Q
Smith
L H
LH
Daniels
C K
CK
D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D004396:Coloring Agents; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D007413:Intestinal Mucosa / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D007978:Levamisole / Q000494:pharmacology; D008099:Liver / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats
D004396:Coloring Agents; D007527:Isoenzymes; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D007978:Levamisole; D000469:Alkaline Phosphatase