miRNA contents of cerebrospinal fluid extracellular vesicles in glioblastoma patients
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Analysis of extracellular vesicles (EVs) derived from plasma or cerebrospinal fluid (CSF) has emerged as a promising biomarker platform for therapeutic monitoring in glioblastoma patients. However, the contents of the various subpopulations of EVs in these clinical specimens remain poorly defined. Here we characterize the relative abundance of miRNA species in EVs derived from the serum and cerebrospinal fluid of glioblastoma patients. EVs were isolated from glioblastoma cell lines as well as the plasma and CSF of glioblastoma patients. The microvesicle subpopulation was isolated by pelleting at 10,000×g for 30 min after cellular debris was cleared by a 2000×g (20 min) spin. The exosome subpopulation was isolated by pelleting the microvesicle supernatant at 120,000×g (120 min). qRT-PCR was performed to examine the distribution of miR-21, miR-103, miR-24, and miR-125. Global miRNA profiling was performed in select glioblastoma CSF samples. In plasma and cell line derived EVs, the relative abundance of miRNAs in exosome and microvesicles were highly variable. In some specimens, the majority of the miRNA species were found in exosomes while in other, they were found in microvesicles. In contrast, CSF exosomes were enriched for miRNAs relative to CSF microvesicles. In CSF, there is an average of one molecule of miRNA per 150–25,000 EVs. Most EVs derived from clinical biofluids are devoid of miRNA content. The relative distribution of miRNA species in plasma exosomes or microvesicles is unpredictable. In contrast, CSF exosomes are the major EV compartment that harbor miRNAs.
KeywordsBiomarkers Biofluids Cancer Exosomes Microvesicles
The work is supported by NIH UH2 TR000931-0, NIH PO1 2P30CA023100-28 (BSC and CCC) and International S&T Cooperation Program of China, 2014DFA31470 (CCC and YM). CCC is supported by the Doris Duke Charitable Foundation Clinical Scientist Development Award, Sontag Foundation Distinguished Scientist Award, Burroughs Wellcome Fund Career Awards for Medical Scientists, the Kimmel Scholar Award, a Grant from Accelerated Brain Cancer Cure, and the William Guy Forbeck Research Foundation.
Conflict of interest
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