Engineering MRI-detectable extracellular vesicles to study breast cancer metastatic organotropism in vivo
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Embargo End Date
2025-08-17
ICR Authors
Authors
O'Driscoll, G
Document Type
Thesis or Dissertation
Date
2025-02-17
Date Accepted
Abstract
Metastatic breast cancer exhibits a non-random distribution of metastases in a distinct pattern of organs, a process referred to as metastatic organotropism. Tumour-derived extracellular vesicles (EVs) are an emerging mediator in the metastatic cascade. EVs are nano-sized, cell-derived vesicles that contain a range of bioactive molecules. Evidence from in vitro and ex vivo studies implicate EVs in metastatic organotropism. However, definitive in vivo evidence of EV localisation to metastatic sites is weaker. This research aimed to engineer MRI-detectable EVs as a tool to image the in vivo localisation of breast cancer-derived EVs in tumour models.
A workflow to isolate EVs from adherent cell lines was validated and further optimised by the adoption of an alternative size exclusion chromatography resin that increased EV yield. To facilitate in vivo study design, two human breast cancer cell lines were then characterised. These cells lines induced different patterns of metastasis in vivo when propagated as orthotopic tumours. Furthermore, the in vitro EVs isolated from these cell lines were enriched for different adhesion proteins. Together, the in vivo characterisation and proteomic results suggested that the EVs derived from these two sub-type cell lines may show different localisation in vivo and are valuable models for downstream studies.
Electroporation was used to load EVs with MRI-detectable ultrasmall superparamagnetic iron oxide (USPIO) particles. USPIO-loaded EVs (USPIO-EVs) were characterised with a range of techniques to optimise loading and purification. Preliminary experiments suggested these USPIO-EVs produce MRI contrast in vitro. An in vivo study was performed, which indicated that any excess free USPIO particles in the final sample would not generate sufficient contrast to interfere with a downstream biodistribution study. Once validated in vivo, the imaging platform developed in this research could be used to investigate the role of EVs in the metastatic organotropism of breast cancer.
Citation
2025
DOI
Source Title
Publisher
Institute of Cancer Research (University Of London)
ISSN
eISSN
Collections
Research Team
Pre-Clinical MRI