New methods for treating cancer are being explored all the time. A review in Biomedical Technology, for example, surveyed the use of tiny bacterial vesicles in precision cancer treatment.
Bacteria naturally release microscopic particles known as bacterial extracellular vesicles (BEVs). This comprises membrane-enclosed tiny particles filled with proteins, lipids, DNA, RNA and metabolites. These particles are now being explored as possible tools for cancer diagnosis and treatment.
The review considers the different ways BEVs could be adapted, including carrying drugs, activating immune responses, limiting metastasis and identifying cancer biomarkers.
Scientists followed recent progress in BEVs, from vesicle formation and purification through molecular analysis, engineering and early testing in cancer models.
“Part of their appeal lies in how they are made,” said senior and co-corresponding author Duanrui Liu. “Scientists can grow bacteria in controlled conditions, alter the bacteria genetically and then modify the released vesicles chemically. This gives researchers several ways to adjust where the vesicles travel and what they carry.”
BEVs could, for example, be fitted with molecules that help them recognise tumors. “Drugs or therapeutic nucleic acids may be packed inside them,” said Liu. “Their bacterial origin also means they can alert the immune system, which may help trigger an anticancer response. The same molecular cargo could provide clues for liquid biopsy or the discovery of new cancer biomarkers.”
Bacterial vesicles are unusual because they can act as both a delivery vehicle and an immune signa. “That combination creates exciting possibilities for precision oncology, but only if the field can make these vesicles consistently and prove that they are safe,” said Liu.
The review also examines potential obstacles, such as inconsistent production, safety risks, contamination and the lack of shared manufacturing and quality standards. While new methods in synthetic biology, microfluidic isolation, multiomics analysis and surface modification are giving researchers finer control over vesicle design, reproducibility remains a persistent problem.
“A change in bacterial strain, culture conditions or purification method can alter the final product,” said first author Xue Gao. “Yields may be low. Harmful bacterial material can remain after purification, and an immune response intended to fight cancer could instead produce damaging inflammation.”
Before BEVs move closer to the clinic, researchers will need more reliable manufacturing, strict testing of each batch and safer ways to reduce unwanted bacterial components. “Their place alongside chemotherapy, radiotherapy and immune checkpoint inhibitors must also be worked out,” said Gao. “If those questions can be answered, these small vesicles may offer a single platform for drug delivery, cancer vaccines, immunotherapy and tumour monitoring.”
