Comparison of enteroendocrine cells and pancreatic β-cells using gene expression profiling and insulin gene methylation

In this study, similarities between EECs and β-cells were evaluated in detail. To obtain specific subtypes of EECs, cell sorting by flow cytometry was conducted from STC-1 cells (a heterogenous EEC line), and each single cell was cultured and passaged. Five EEC subtypes were established according to hormone expression, measured by quantitative RT-PCR and immunostaining: L, K, I, G and S cells expressing glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide, cholecystokinin, gastrin and secretin, respectively. Global microarray gene expression profiles revealed a higher similarity between each EEC subtype and MIN6 cells (a β-cell line) than between C2C12 cells (a myoblast cell line) and MIN6 cells, and all EEC subtypes were highly similar to each other. Genes for insulin secretion-related proteins were mostly enriched in EECs. A total of 100 ng of RNA from each sample was amplified to make cDNA using the GeneChip Whole Transcript Amplification kit according to the supplied protocol. The sense cDNA was then fragmented and biotin-labeled with terminal deoxynucleotidyl transferase using the GeneChip Whole Transcript Terminal Labeling kit. A 5500-ng sample of each cDNA was hybridized to the Affymetrix GeneChip Mouse 2.0 ST Arrays at 45°C for 16 h. Hybridized arrays were scanned using a GSC3000 Scanner.