Bacterial outer membrane vesicles as a candidate tumor vaccine platform

Abstract

Cancer represents a serious concern for human life and health. Due to drug resistance and the easy metastasis of tumors, there is urgent need to develop new cancer treatment methods beyond the traditional radiotherapy, chemotherapy, and surgery. Bacterial outer membrane vesicles (OMVs) are a type of double-membrane vesicle secreted by Gram-negative bacteria in the process of growth and life, and play extremely important roles in the survival and invasion of those bacteria. In particular, OMVs contain a large number of immunogenic components associated with their parent bacterium, which can be used as vaccines, adjuvants, and vectors to treat diseases, especially in presenting tumor antigens or targeted therapy with small-molecule drugs. Some OMV-based vaccines are already on the market and have demonstrated good therapeutic effect on the corresponding diseases. OMV-based vaccines for cancer are also being studied, and some are already in clinical trials. This paper reviews bacterial outer membrane vesicles, their interaction with host cells, and their applications in tumor vaccines.

Recent advances in therapeutic engineered extracellular vesicles

“…OMVs, especially from E. coli ., are utilized in tumor therapy, as LPSs on the surface of OMVs are immunomodulators to activate an immune response. 46,47…”

Outer Membrane Vesicles (OMVs) as Biomedical Tools and Their Relevance as Immune-Modulating Agents against H. pylori Infections: Current Status and Future Prospects

“…For instance, OMVs can play a significant anti-infection role by inducing and modulating immune responses or by inhibiting pathogen localization and proliferation. Thus, OMVs are recognized as promising candidates for various biomedical applications such as immune modulation, drug delivery, cancer therapy, vaccine development, and anti-bacterial treatments [15,[17][18][19][20][21][22][23][24][25][26]; however, their full potential, advantages, future perspectives, and associated problems need to be further investigated.…”

“…Moreover, OMVs can combine several desirable effects such as delivering the targeted drug (e.g., chemotherapeutic agents) into the specific (e.g., tumor) microenvironment and at the same time recruit immune cells into it, and therefore, enhance their efficacy with no apparent toxicity [45][46][47]. In this regard, naturally acquired OMVs could be used directly or could be modified or genetically engineered to achieve this aim [20,24,25,48,49]. Naturally derived OMVs can serve as DNA, RNA, antigen, and antibody carriers, or as delivery vehicles for their natural cargos (Figure 3A).…”

“…The use as agents in cancer immunotherapy to annihilate tumor tissues is another intriguing OMV application (Figure 4C). OMVs have been proposed as a good platform for anti-tumor vaccine development for several reasons, such as OMV strong immunogenicity, the ability of OMVs to carry the anti-tumor antigen (inside the vesicle or on its surface), to enhance the antigen presentation, and the lack of OMV proliferation [19,20]. OMV-based anti-tumor vaccines are primarily developed by genetic engineering to express a foreign protein inside the OMVs or linked to the OMV surfaces.…”

Tumor Microenvironment Regulation and Cancer Targeting Therapy Based on Nanoparticles

“…Nanomaterials mainly regulate TME through the following four mechanisms: (i). Promote the immunogenicity of cancer antigens [ 27 , 28 , 29 , 30 , 31 ]; (ii). Activate disabled immune cells [ 32 , 33 , 34 , 35 , 36 ]; (iii).…”