There is growing evidence that microRNAs (miRNAs) may play a critical role in many types of cancer. Investigating miRNA targeting of genes differentially expressed in tumor samples could lead to a better understanding of malignancy. We profiled differential miRNA expression using the NCode™ miRNA microarray platform in normal and malignant breast tissue while also examining secreted proteins by mass spectrometry combined with stable isotopic labeling by amino acids in cell culture (SILAC). Several miRNAs and proteins were found to be differentially expressed between normal and tumor samples. In many cases, putative miRNA binding sites were found in the 3’UTRs of differentially expressed gene mRNAs. Using miRNA mimetics to over express the miRNA in a normal breast epithelial cell line, we are investigating the functional correlation between the miRNA and protein using the SYBR® Green qRT-PCR system and SILAC. Results from these studies will be presented.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA