Expression signature in a human colorectal cancer cell line HCT116 transfected with miR-1 precursor molecule

We identified that miR-1 is silenced in association with CpG island hypermethylation in a colorectal cancer (CRC) cell line, HCT116. To determine whether miR-1 serves as a tumor suppressor in CRC, we transfected CRC cell lines with a miR-1 precursor molecule or a negative control, and carried then out a series of MTT assays. Forty-eight hours after transfection, we observed that ectopic expression of miR-1 moderately suppressed growth in all three cell lines. To further clarify the effect of the miRNA, we next performed gene expression microarray analysis in HCT116 cells transfected with a miR-1 precursor molecule or a negative control. We found that 2769 probe sets were downregulated (> 1.5-fold) by ectopic miR-1 expression, and gene ontology analysis revealed that “extracellular regions”, “membrane” and “response to wound healing” genes were significantly enriched among the downregulated genes. HCT116 cells were transfected with a Pre-miR-1 miRNA Precursor Molecule (Ambion) or Pre-miR miRNA Molecules Negative Control #1 (Ambion). Forty-eight hours after transfection, total RNA extraction were carried out, and gene expression signatures were analyzed.