Abstract
The purpose of this study was to determine if microvesicle (MV) subpopulations as defined by surface protein composition also exhibit distinct microRNA (miR) expression patterns. Microvesicles isolated from a prostate cancer cell line (VCaP) were sorted based on their surface protein composition and were evaluated for differential expression of miRs. Phycoerythrin-labeled antibodies targeting EpCAM, CD63, or B7-H3 were used to sort the subpopulations of MVs by fluorescence-activated cell sorting. The sorted subpopulations of MVs were subsequently profiled by miR expression. The miR profiles for the EpCam-, CD63-, and B7-H3–positive subpopulations were compared with the profile of the total VCaP MV population. Differential miR expression patterns were observed across the subpopulations, and all expression patterns were distinct from that observed in the total population. Patterns of both over- and under-expression were seen. Not only can subpopulations of MVs be distinguished and separated based on surface protein markers, but they can also be differentiated based on their RNA content, in this case miRs. The ability to isolate tissue-specific cMV populations from patient plasma based on surface protein composition and then analyze them based on both surface protein composition and genetic content has considerable diagnostic, prognostic, and theranostic implications.