Engineering Optimized EV-Mimetic Carriers for Efficient Tumor-Targeted Delivery of Functional RNA Nanoparticles

Area of Science:

• Biotechnology
• Nanomedicine
• Molecular Biology

Background:

• The clinical translation of RNA interference (RNAi) therapeutics is hindered by challenges in developing safe, scalable, and efficient delivery systems.
• Extracellular vesicles (EVs) show promise as natural carriers for RNA therapeutics, but their clinical application is limited by poor scalability and low cargo-loading efficiency.
• There is a critical need for advanced delivery platforms that can overcome these limitations for effective nucleic acid therapy.

Purpose of the Study:

• To develop and evaluate fully synthetic extracellular vesicle-mimetic (EVM) carriers for delivering RNAi-inducing RNA nanoparticles to tumor cells.
• To systematically assess different EVM cargo-loading strategies for optimizing size, concentration, and encapsulation efficiency.
• To compare the cellular uptake, RNA delivery, and gene-silencing efficacy of EVMs against natural EVs and conventional lipid-based carriers.

Main Methods:

• Four distinct EVM cargo-loading strategies were evaluated using RNA nanoparticles and appropriate controls.
• EVM characteristics, including size, concentration, and cargo encapsulation efficiency, were systematically assessed.
• Cellular uptake and RNA delivery were examined in melanoma 3D spheroids, with functional RNAi activation assessed in tumor monolayers and spheroids.

Main Results:

• EVMs demonstrated superior cellular uptake and RNA delivery efficiency in melanoma 3D spheroids compared to natural tumor-derived EVs.
• Effective gene silencing was achieved in tumor models using EVMs, showing lower toxicity than conventional lipid-based carriers.
• Optimal loading strategies and RNA nanoparticle designs were identified for maximizing gene-silencing efficacy.

Conclusions:

• Fully synthetic EVMs represent a safe, scalable, and efficient biomimetic platform for therapeutic nucleic acid delivery.
• EVMs overcome the limitations of natural EVs and conventional carriers, offering enhanced delivery and reduced toxicity for RNAi therapeutics.
• This study provides a foundation for the clinical translation of EVM-based delivery systems for cancer therapy and other applications.