A methodology for distinguishing divergent cell fates within a common progenitor population: adenoma- and neuroendocrine-like cells are confounders of rat ileal epithelial cell (IEC-18) culture.
BACKGROUND
IEC-18 cells are a non-transformed, immortal cell line derived from juvenile rat ileal crypt cells. They may have experimental advantages over tumor-derived gastrointestinal lineages, including preservation of phenotype, normal endocrine responses and retention of differentiation potential. However, their proclivity for spontaneous differentiation/transformation may be stereotypical and could represent a more profound experimental confounder than previously realized. We hypothesized that IEC-18 cells spontaneously diverge towards a uniform mixture of epigenetic fates, with corresponding phenotypes, rather than persist as a single progenitor lineage.


RESULTS
IEC-18 cells were cultured for 72 hours in serum free media (SFM), with and without various insulin-like growth factor agonists to differentially boost the basal rate of proliferation. A strategy was employed to identify constitutive genes as markers of divergent fates through gene array analysis by cross-referencing fold-change trends for individual genes against crypt cell abundance in each treatment. We then confirmed the cell-specific phenotype by immunolocalization of proteins corresponding to those genes. The majority of IEC-18 cells in SFM alone had a loss in expression of the adenomatous polyposis coli (APC) gene at the mRNA and protein levels, consistent with adenoma-like transformation. In addition, a small subset of cells expressed the serotonin receptor 2A gene and had neuroendocrine-like morphology.


CONCLUSIONS
IEC-18 cells commonly undergo a change in cell fate prior to reaching confluence. The most common fate switch that we were able to detect correlates with a down regulation of the APC gene and transformation into an adenoma-like phenotype.
Gordon
Phillip V
PV
Department of Pediatrics, University of Virginia, PO Box 800386, Charlottesville, VA 22908, USA. pvg4n@virginia.edu
Paxton
Jessica B
JB
Fox
Nena S
NS
D000236:Adenoma / Q000473:pathology; D000818:Animals; D018278:Carcinoma, Neuroendocrine / Q000473:pathology; D002460:Cell Line; D019070:Cell Lineage; D003584:Cytological Techniques / Q000379:methods*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017491:Genes, APC; D007082:Ileum / Q000166:cytology*; D008722:Methods; D010641:Phenotype; D051381:Rats; D013234:Stem Cells / Q000166:cytology*