Expression data from intestinal epithelial cells (IECs) [MoGene-1_0-st array]

Polycomb group (PcG) proteins are epigenetic silencers whose dysregulation is frequently linked to cancer via mechanisms that remain unclear. Using conditional knock-out mice in a colitis-associated colorectal cancer (CAC) model, we found that Bmi1 and Mel18 are important initiation and maintenance factors during CAC tumorigenesis. Epithelial depletion of both Bmi1 and Mel18, but not either gene alone, significantly reduces tumor growth and multiplicity. We used microarrays to detail the global program of gene expression In DKO, Bmi1ΔIEC, Mel18ΔIEC and WT mice and identified distinct classes of up-regulated genes during this process. Mouse IECs were selected at early stages of CAC tumorigenesis for RNA extraction and hybridization on Affymetrix microarrays. To that end, we isolated IECs from the freshly dissected colon of DKO (1), Bmi1ΔIEC (2), Mel18ΔIEC (3) and WT (4) mice for Mouse Gene 1.0 ST array.