Breast and colorectal cancers present significant challenges for the UK healthcare system, placing a substantial burden on the National Health Service (NHS). Early detection is crucial for improving survival rates and reducing healthcare strain, especially as metastasis, the primary cause of mortality in these cancers, remains poorly understood. Protein glycosylation, a post-translational modification of carbohydrate structures, is a significant contributor to cancer progression and metastasis. Small extracellular vesicles (sEVs) have emerged as key players in cancer development and metastasis, facilitating intercellular communication through bioactive cargo transfer. Despite mounting evidence, the importance of sEV glycosylation in cancer and metastasis is often overlooked. Liquid biopsies, including sEV biomarker analysis, offer promising non-invasive diagnostic approaches. Given the prevalence of glycoproteins among blood cancer biomarkers, exploring the glycosylation of sEVs as biomarker targets could revolutionise early detection strategies for breast and colorectal cancer. Efforts initially focused on optimising single-vesicle flow cytometry for sEV characterisation to ensure maximum signal and sample integrity. Subsequent analysis of breast and colorectal epithelial cells and their derived sEVs revealed pronounced HPA lectin binding in the metastatic phenotypes. A lectin microarray identified increased lectin binding of LCA and TL in ‘CD81-positive’ sEVs derived from breast cancer-associated cell lines in comparison to normal cells. Validation through single-vesicle flow cytometry confirmed these observations, prompting investigations into the diagnostic application of these lectins in distinguishing plasma-enriched sEVs from breast cancer patients and ‘healthy’ individuals. However, lectins alone did not show diagnostic significance, in contrast to the diagnostic capability of the well-established breast cancer marker EpCAM. Overall, these results underscore the importance of optimising single-vesicle flow cytometry for comprehensive characterisation of sEVs. They also highlight the HPA lectin binding patterns of breast and colorectal metastatic cell phenotypes, which mirror the observations of their derived sEVs but with nuanced specificity attributed to tetraspanin composition. Additionally, other glycosylated targets, as recognised by TL and LCA, show increased abundance in breast cancer cell-derived sEVs. Moreover, the diagnostic capability of these lectins and EpCAM in distinguishing plasma-enriched sEVs derived from breast cancer patients from those derived from ‘healthy’ individuals is demonstrated.
Permanent link to this resource: https://doi.org/10.24384/q2yw-8493
Cooper, Jamie
Supervisors: Brooks, Susan; Pink, Ryan
Faculty of Health and Life Sciences
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