New approach for the capture of tumor-derived exosomes from a prostate cancer cell line

Findings enable a non-invasive approach for diagnosis and prognosis of prostate cancer

Figure a shows captured exosomes on ligand-baited nanosprings, the exosomes are indicated by the arrows. Figure b shows a TEM image of captured exosomes following negative staining with phosphotungstic acid (PTA) PH = 7.1.

In a new paper in Springer's Journal of Materials Science, researchers at Washington State University report a new approach for the effective capture of tumor-derived exosomes from a prostate cancer cell line. Exosomes are small secreted vesicles that play a key role in intercellular communication and cancer progression.

Developing effective and high-throughput selective capture technology for exosomes bearing the prostate-speci􀃒c membrane antigen (PSMA) biomarker is critical for early diagnostic and prognostic evaluation of prostate cancer and treatment planning. It is known that the prostate tumor enzyme-biomarker PSMA is highly enriched in exosomes secreted by PSMA+ prostate cancer cells. A novel biofunctionalized silica nanostructure was designed to selectivity capture tumor-derived exosomes through the interaction of a known PSMA ligand with the PSMA on the exosomes.

This work enables a non-invasive approach for diagnosis and prognosis of prostate cancer. It overcomes many of the limitations of alternative approaches that are often ine􀃗ective in isolating tumor-derived exosomes from those derived from normal tissue because of the low recovery yields and the time required for the process.

The concept was demonstrated using a single cancer type (i.e., prostate cancer), but based on the data presented in this study, the authors expect that a broad panel of biomarker ligands can be baited on the silica nanostructures to selectively capture biomarker-positive exosomes from an array of cell types. Further advantages of the approach used in this study are the ability to isolate a speci􀃒c subpopulation of exosomes relying on

the expression of a speci􀃒c surface marker as well as improved exosome recovery rate. In the future, the authors envision a microfluidic flow device that will allow for increased exosome capture efficiency and clinical applications.

Reference: Parissa Ziaei, Jonathan J. Geruntho, Oscar Marin-Flores, Cli􀃗ord E. Berkman, M. Grant Norton. (2017). Silica Nanostructured Platform for Affinity Capture of Tumor-Derived Exosomes, Journal of Materials Science. DOI 10.1007/s10853-017-0905-0

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