Plasma Preparation Strategies for Extracellular Vesicle-Based Biomarkers in Metastatic Castration-Resistant...

Area of Science:

• Biochemistry
• Oncology
• Nanotechnology

Background:

• Extracellular vesicles (EVs) are promising for cancer detection, but standardization is lacking.
• Clinical utility of EV biomarkers is limited by inconsistent sample preparation and isolation methods.
• Accurate analysis of plasma EV content is crucial for metastatic castration-resistant prostate cancer (mCRPC) patient management.

Purpose of the Study:

• To investigate the impact of clinical sample preparation variables on plasma-derived EV quality and content in mCRPC patients.
• To evaluate the efficacy of the ExoTIC device for EV isolation and biomarker analysis.
• To identify optimal biospecimen preparation for enhanced detection accuracy of EV-associated biomarkers.

Main Methods:

• Assessed effects of anticoagulant choice (EDTA vs. sodium citrate), plasma platelet fraction (platelet-rich vs. platelet-poor), and protease inhibitors.
• Isolated EVs using the ExoTIC device.
• Characterized EVs and analyzed RNA/protein cargo via nanoparticle tracking analysis, cryogenic electron microscopy, Western blot, and digital PCR.

Main Results:

• mCRPC-relevant proteins (ARv7, PSMA) were detected in EVs across all tested plasma sample types.
• Platelet-poor plasma (PPP) proved optimal for detecting the mCRPC biomarker miR-375.
• Elevated EV miR-375 in PPP correlated with poor docetaxel response in progressing mCRPC patients (n=3).

Conclusions:

• Optimal biospecimen preparation enhances the accuracy of EV biomarker detection for mCRPC.
• Standardized EV analysis, particularly using PPP, can improve patient management and therapeutic response prediction.
• Detection of plasma EV-associated proteins (ARv7, PSMA) and microRNA (miR-375) holds significant clinical potential.