Microarray analysis of miRNA in breast cancer cell lines

The project aimed to identify miRNA that varied with tumourigenicity in human breast cell lines. The second objective was to identify miRNA that had differential expression between cell lines that varied in accordance with the abundance of the tetraspanin CD9 in the cell lines and the degree to which endogenous factors within these cell lines interacted with the 3'UTR of CD9 as determined by dual luciferase assay. These miRNA were considered potential regulators of the abundance of CD9 in breast cancer. Total RNA was isolated from commercial breast cancer cell lines and non-tumourigenic breast cell lines and the abundance of each miRNA was determined by hybridisation to affymetrix miRNA microarrays. RNA was combined from 3 independent cultures of each cell line prior to labelling for hybridisation to each array. Each cell line was therefore only assayed once by microarray.