Bacteria shed membrane-enclosed tiny particles filled with proteins, lipids, DNA, RNA and metabolites. These particles, commonly known as bacterial extracellular vesicles (BEVs), are now being explored as possible tools for cancer diagnosis and treatment.
A review published in Biomedical Technology surveys recent progress in BEVs, following the process 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,” shares 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 recognize tumors. “Drugs or therapeutic nucleic acids may be packed inside them,” says 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.”
Notably, 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,” adds Liu.
The authors also compared BEVs with mammalian extracellular vesicles and conventional nanocarriers. New methods in synthetic biology, microfluidic isolation, multiomics analysis and surface modification are giving researchers finer control over vesicle design. Reproducibility, though, remains a persistent problem.
“A change in bacterial strain, culture conditions or purification method can alter the final product,” explains 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,” adds Gao. “If those questions can be answered, these small vesicles may offer a single platform for drug delivery, cancer vaccines, immunotherapy and tumor monitoring.”
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Contact the author:
Duanrui Liu, Department of Clinical Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; duanrui@hku.hk.
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Biomedical Technology
Literature review
Not applicable
Bacterial extracellular vesicle technology for precision cancer medicine: Biotechnological advances and applications
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.