Abstract

Circulating microvesicles (cMVs) isolated from either blood plasma or serum can yield genetic material sufficient for informative microRNA (miR) expression analysis. The ability to purify RNA from MV isolated from several sources was compared, and the miR expression patterns were determined. cMVs were isolated from the blood plasma and serum of men with and without prostate cancer, as well as from healthy and prostate tumor tissue and prostate cancer cell lines. Total RNA was extracted from the plasma and cell line microvesicles (MVs) using the Qiagen miReasy kit and from the serum cMVs using the ExoMir extraction method. The miR expression was determined for each source using Agilent V3 miRNA microarrays. Each sample (300ng) was hybridized to the microarrays, and the acquired data were analyzed with the GeneSpring software package. Expression patterns for miRs from cMVs isolated from the plasma and serum of men with and without prostate cancer were evaluated for significant differences. Hierarchical clustering on both samples and genes demonstrated a distinct expression pattern for miRs from plasma cMVs compared with miRs from cell line MVs and tumor tissue. These findings demonstrate that cMVs isolated from the peripheral blood offer a unique and potentially clinically relevant source of miR for blood-based analysis.