Affiliations: [a] Discipline of Surgery, Lambe Institute for Translational Research, National University of Ireland Galway, Galway, Ireland | [b] School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland | [c] Discipline of Anatomy, National University of Ireland Galway, Galway, Ireland | [d] Department of Colorectal Surgery, Galway University Hospital, Galway, Ireland
Correspondence:
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Corresponding author: Roisin M. Dwyer, Discipline of Surgery, Lambe Institute for Translational Research, Galway, Ireland. E-mail:roisin.dwyer@nuigalway.ie
Abstract: BACKGROUND: Cells release extracellular membrane vesicles including
microvesicles known as exosomes. Exosomes contain microRNAs (miRNAs) however
the full range within colorectal cancer cell secreted exosomes is unknown. OBJECTIVE: To identify the full range of exosome encapsulated
miRNAs secreted from 2 colorectal cancer cell lines and to investigate
engineering of exosomes over-expressing miRNAs. METHODS: Exosomes were isolated from HCT-116 and HT-29 cell lines.
RNA was extracted from exosomes and microRNA array performed. Cells were
engineered to express miR-379 (HCT-116-379) or a non-targeting control
(HCT-116-NTC) and functional effects were determined. Exosomes secreted by
engineered cells were transferred to recipient cells and the impact
examined. RESULTS: Microvesicles 40-100 nm in size secreted by cell lines were
visualised and confirmed to express exosomal protein CD63. HT-29 exosomes
contained 409 miRNAs, HCT-116 exosomes contained 393, and 338 were common to
exosomes from both cell lines. Selected targets were validated. HCT-116-379
cells showed decreased proliferation (12-15% decrease, p < 0.001) and
decreased migration (32-86% decrease, p < 0.001) compared to controls.
HCT-116-379 exosomes were enriched for miR-379. Confocal microscopy
visualised transfer of HCT-116-379 exosomes to recipient cells. CONCLUSIONS: Colorectal cancer cells secrete a large number of
miRNAs within exosomes. miR-379 decreases cell proliferation and migration,
and miR-379 enriched exosomes can be engineered.
