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Ovarian cancer is one of the most difficult cancers to treat because it is often diagnosed after it has spread and many tumors eventually become resistant to available therapies. One promising strategy is to use extracellular vesicles, also called EVs or exosomes, as natural delivery vehicles that can transport therapeutic molecules directly to cancer cells.
Researchers from the University of Queensland, Australia, have developed a scalable method to engineer extracellular vesicles that selectively deliver molecular cargo to ovarian tumors. Their approach could help advance the development of more precise cancer therapies while also making large-scale manufacturing of engineered extracellular vesicles more practical.
Extracellular vesicles are tiny membrane-bound particles naturally released by cells. They carry proteins, RNA, lipids, and other molecules that allow cells to communicate with one another. Because EVs are already used by the body to transport biological cargo, scientists are investigating whether they can be adapted to safely deliver therapeutic molecules to diseased tissues.
EV cargo loading was optimized by comparing vesicle-anchoring domains to enhance reporter protein packaging. The selected strategy was applied to scalable production using mammalian cell systems, followed by the generation of stable engineered cell lines for consistent EV yield. Engineered EVs were then evaluated in ovarian cancer PDX models to assess in vivo biodistribution and tumor targeting.
The researchers first optimized how cargo is loaded into extracellular vesicles by comparing several different vesicle-anchoring proteins. This allowed them to identify a scaffold that efficiently packaged a bioluminescent reporter into engineered EVs.
The team also compared EV production using five cell lines commonly used in biopharmaceutical manufacturing. They found that engineered ExpiCHO cells consistently produced large quantities of extracellular vesicles, making them a promising platform for future commercial manufacturing.
To ensure the engineered vesicles reached ovarian tumors, the researchers modified a membrane protein called PTGFRN to display the targeting molecule Ephrin-B2 on the EV surface. Ephrin-B2 binds strongly to the EphB4 receptor, which is highly expressed in many advanced ovarian cancers.
When the engineered extracellular vesicles were administered in animal models, they preferentially accumulated in EphB4-positive tumor cells instead of distributing evenly throughout the body. Because the vesicles also carried a bioluminescent cargo, the researchers could track where they traveled and confirm that the therapeutic cargo reached the tumor.
The team further evaluated the platform using patient-derived xenograft models, which are created by implanting tumor tissue from patients into mice. These models more closely resemble human cancers than traditional laboratory cell lines.
Engineered extracellular vesicles displaying Ephrin-B2 selectively localized to tumors with high EphB4 expression while showing much lower accumulation in tumors with lower receptor levels. The imaging system also allowed researchers to visualize how the delivered cargo spread throughout the tumor after reaching its target.
One of the biggest challenges for extracellular vesicle therapies has been manufacturing enough consistent material for clinical use. By identifying a robust production platform and demonstrating selective targeting, the researchers addressed two important barriers to future clinical translation.
Although additional testing will be needed before this technology reaches patients, the results suggest engineered extracellular vesicles could become versatile delivery vehicles for a wide range of cancer therapies. Beyond ovarian cancer, similar approaches could potentially be adapted for other diseases that express unique surface receptors, enabling more precise delivery while reducing unwanted effects on healthy tissues.
