A conserved microRNA signature related to cellular transformation by the RAS oncogene (Affymetrix mRNA)

The differential expression of microRNAs in Ras transformed epithelial cells of human and rat origin was investigated. Here we describe the group of miRNAs differentially expressed in two Ras transformed cell lines and defined it as a miRNA Ras signatures. We show that expression of these miRNAs are also affected in different primary tumors with high frequency of Ras mutation. We demonstate that introduction of different miRNAs lost during Ras transformation have big influence on cellular phenotype and mRNA expression. Importance of Ras pathway dependent transcription factors for miRNA regulation was shown as well. The complexity of miRNA – signal transduction pathways interactions and importance of miRNA regulation in Ras dependent malignant tumor formation is discussed. Total RNA obtained from human embryonic kidney and rat ovarian surface epithelium cells, RAS transformed, mir22 mimicked, FRA1 silenced.