Low-Density Taqman miRNA Array Reveals miRNAs Differentially Expressed in Prostatic Stem Cells and Luminal Cells

BACKGROUND. miRNAs are a class of naturally occurring small RNAs that generally repress gene expression. They have been shown to actively control diverse biological processes including stem cell differentiation and lineage commitment. METHODS. Fluorescence-activated cell sorting was utilized to isolate murine prostate stem cells and differentiated luminal cells. The expression levels of Drosha and Dicer1, the two key RNAseIII enzymes for miRNA maturation, were evaluated by quantitative RT-PCR. Low-density Taqman miRNA array analyses were also performed to identify miRNAs that are differentially expressed in individual lineages. RESULTS. Drosha and Dicer1 are expressed at comparable transcriptional levels in murine prostate stern cells and differentiated luminal cells. Twenty-nine miRNAs were discovered to be differentially expressed in prostate stem cells and luminal cells. Many of these miRNAs are coded in clusters, suggesting a cell-specific transcriptional regulation. Some of these differentially expressed miRNAs have been reported to regulate genes relevant to the molecular and phenotypic features of each lineage. CONCLUSIONS. miRNAs may play a potentially critical role in fine regulation of prostatic lineage identity. Prostate 70: 297-304, 2010. (C) 2009 Wiley-Liss, Inc.