Recent Advancement and Technical Challenges in Developing Small Extracellular Vesicles for Cancer Drug Delivery

Electroporation enhances cell death in 3D scaffold-based MDA-MB-231 cells treated with metformin

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer lacks estrogen, progesterone, and HER2 receptors and hence, is therapeutically challenging. Towards this, we studied an alternate therapy by repurposing metformin (FDA-approved type-2 diabetic drug with anticancer properties) in a 3D-scaffold culture, with electrical pulses. 3D cell culture was used to simulate the tumor microenvironment more closely and MDA-MB-231, human TNBC cells, treated with both 5 mM metformin (Met) and 8 electrical pulses at 2500 V/cm, 10 µs (EP1) and 800 V/cm, 100 µs (EP2) at 1 Hz were studied in 3D and 2D. They were characterized using cell viability, reactive oxygen species (ROS), glucose uptake, and lactate production assays at 24 h. Cell viability, as low as 20 % was obtained with EP1 + 5 mM Met. They exhibited 1.65-fold lower cell viability than 2D with EP1 + 5 mM Met. ROS levels indicated a 2-fold increase in oxidative stress for EP1 + 5 mM Met, while the glucose uptake was limited to only 9 %. No significant change in the lactate production indicated glycolytic arrest and a non-conducive environment for MDA-MB-231 growth. Our results indicate that 3D cell culture, with a more realistic tumor environment that enhances cell death using metformin and electrical pulses could be a promising approach for TNBC therapeutic intervention studies.

Versatile functionalization of Bifidobacteria-derived extracellular vesicles using amino acid metabolic labeling and click chemistry for immunotherapy

Extracellular vesicles (EVs) are nanoparticles secreted by various organisms. Methods for modifying EVs functionally have garnered attention for developing EV-based therapeutic systems. However, most technologies used to integrate these functions are limited to mammalian-derived EVs and a promising modification method for bacteria-derived EVs has not yet been developed. In this study, we propose a novel method for the versatile functionalization of immunostimulatory probiotic Bifidobacteria-derived EVs (B-EVs) using amino acid metabolic labeling and azide-alkyne click reaction. Azide D-alanine (ADA), a similar molecule to D-alanine in bacteria cell-wall peptidoglycan, was selected as an azide group-functionalized amino acid. Azide-modified B-EVs were isolated from Bifidobacteria incubated with ADA. The physicochemical and compositional characteristics, as well as adjuvanticity of B-EVs against immune cells were not affected by azide loading, demonstrating that this functionalization approach can retain the endogenous usefulness of B-EVs. By using the fluorescent B-EVs obtained by this method, the intracellular trafficking of B-EVs after uptake by immune cells was successfully observed. Furthermore, this method enabled the formulation of B-EVs for hydrogelation and enhanced adjuvanticity in the host. Our findings will be helpful for further development of EV-based immunotherapy.

Thinking small to win big? A critical review on the potential application of extracellular vesicles for biomarker discovery and new therapeutic approaches in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely deadly form of cancer, with limited progress in 5-year survival rates despite significant research efforts. The main challenges in treating PDAC include difficulties in early detection, and resistance to current therapeutic approaches due to aggressive molecular and microenvironment features. These challenges emphasize the importance of identifying clinically validated biomarkers for early detection and clinical management. Extracellular vesicles (EVs), particularly exosomes, have emerged as crucial mediators of intercellular communication by transporting molecular cargo. Recent research has unveiled their role in initiation, metastasis, and chemoresistance of PDAC. Consequently, utilizing EVs in liquid biopsies holds promise for the identification of biomarkers for early detection, prognosis, and monitoring of drug efficacy. However, numerous limitations, including challenges in isolation and characterization of homogeneous EVs populations, as well as the absence of standardized protocols, can affect the reliability of studies involving EVs as biomarkers, underscoring the necessity for a prudent approach. EVs have also garnered considerable attention as a promising drug delivery system and novel therapy for tumors. The loading of biomolecules or chemical drugs into exosomes and their subsequent delivery to target cells can effectively impede tumor progression. Nevertheless, there are obstacles that must be overcome to ensure the accuracy and efficacy of therapies relying on EVs for the treatment of tumors. In this review, we examine both recent advancements and remaining obstacles, exploring the potential of utilizing EVs in biomarker discovery as well as for the development of drug delivery vehicles.

Fast, simple and calibration-free size characterization and quality control of extracellular vesicles using capillary Taylor dispersion analysis

This study reports the development of a Taylor Dispersion Analysis (TDA) method for the size characterization of Extracellular Vesicles (EVs), which are highly heterogeneous nanoscale cell-derived vesicles (30-1000 nm). Here, we showed that TDA, conducted in uncoated fused silica capillaries (50 µm i.d.) using a conventional Capillary Electrophoresis instrument, is able to provide absolute sizing (requiring no calibration) of bovine milk-derived EVs in a small sample volume (∼ 7 nL) and over their entire size range, even the smallest ones (< 70 nm) not accessible via other techniques that provide nanoparticle sizing in suspension. TDA size measurements were repeatable (RSD < 10%) and the average EV sizes were found in the range of 120-210 nm, in very good agreement with those measured with Nanoparticle Tracking Analysis, commonly used for EV characterization. TDA allowed quantitative estimation of EVs for concentrations ≥ 2 × 1011 EVs/mL. Furthermore, TDA was able to detect minor changes in EV size (i.e. by ∼25 nm upon interaction with specific anti-CD9 antibodies of ∼150 kDa), and to highlight the impact of extraction methods (i.e. milk pretreatment: freezing, acid precipitation or centrifugation; the type of size-exclusion chromatography column) and of fluorescent labeling (i.e. intravesicular or surface labeling) on the isolated EV population size. In parallel to EV sizing, TDA allowed to detect molecular contaminants (average sizes ∼1-13 nm) present within the sample, rendering this method a valuable tool to assess the quality and quantity of EV isolates.

Extracellular vesicles: a rising star for therapeutics and drug delivery

Extracellular vesicles (EVs) are nano-sized, natural, cell-derived vesicles that contain the same nucleic acids, proteins, and lipids as their source cells. Thus, they can serve as natural carriers for therapeutic agents and drugs, and have many advantages over conventional nanocarriers, including their low immunogenicity, good biocompatibility, natural blood-brain barrier penetration, and capacity for gene delivery. This review first introduces the classification of EVs and then discusses several currently popular methods for isolating and purifying EVs, EVs-mediated drug delivery, and the functionalization of EVs as carriers. Thereby, it provides new avenues for the development of EVs-based therapeutic strategies in different fields of medicine. Finally, it highlights some challenges and future perspectives with regard to the clinical application of EVs.

CRISPR/Cas9 as a therapeutic tool for triple negative breast cancer: from bench to clinics

Clustered regularly interspaced short palindromic repeats (CRISPR) is a third-generation genome editing method that has revolutionized the world with its high throughput results. It has been used in the treatment of various biological diseases and infections. Various bacteria and other prokaryotes such as archaea also have CRISPR/Cas9 systems to guard themselves against bacteriophage. Reportedly, CRISPR/Cas9-based strategy may inhibit the growth and development of triple-negative breast cancer (TNBC) via targeting the potentially altered resistance genes, transcription, and epigenetic regulation. These therapeutic activities could help with the complex issues such as drug resistance which is observed even in TNBC. Currently, various methods have been utilized for the delivery of CRISPR/Cas9 into the targeted cell such as physical (microinjection, electroporation, and hydrodynamic mode), viral (adeno-associated virus and lentivirus), and non-viral (liposomes and lipid nano-particles). Although different models have been developed to investigate the molecular causes of TNBC, but the lack of sensitive and targeted delivery methods for in-vivo genome editing tools limits their clinical application. Therefore, based on the available evidences, this review comprehensively highlighted the advancement, challenges limitations, and prospects of CRISPR/Cas9 for the treatment of TNBC. We also underscored how integrating artificial intelligence and machine learning could improve CRISPR/Cas9 strategies in TNBC therapy.

Functionalisation of extracellular vesicles with cyclic-RGDyC potentially for glioblastoma targeted intracellular drug delivery

With the intrinsic ability to cross the blood-brain barrier, small extracellular vesicles (sEVs) hold promise as endogenous brain-targeted drug delivery nano-platforms for glioblastoma (GBM) treatment. To increase GBM targetability, this study aimed to functionalise sEVs with cyclic arginine-glycine-aspartic acid-tyrosine-cysteine (cRGDyC), a ligand for integrin (α_vβ₃) that is overexpressed in GBM cells. Firstly, the intrinsic cellular uptake of sEVs derived from GBM U87 and pancreatic cancer MIA PaCa-2 cells was investigated on the donor cells. To obtain functionalised sEVs (cRGDyC-sEVs), DSPE-mPEG₂₀₀₀-maleimide was incubated with the selected (U87) sEVs, and cRGDyC was subsequently conjugated to the maleimide groups via a thiol-maleimide coupling reaction. The GBM cell targetability and intracellular trafficking of cRGDyC-sEVs were evaluated on U87 cells by fluorescence and confocal microscopy, using unmodified sEVs as a reference. The cytotoxicity of doxorubicin-loaded vesicles (Dox@sEVs, Dox@cRGDyC-sEVs) was compared with a standard liposome formulation (Dox@Liposomes) and free Dox. Both U87 and MIA PaCa-2 cell-derived sEVs displayed tropism with the former being >4.9-fold more efficient to be internalised into U87. Therefore, the U87-derived sEVs were chosen for GBM-targeting. Approximately 4000 DSPE-mPEG₂₀₀₀-maleimide were inserted onto each sEV with cRGDyC conjugated to the maleimide group. The cell targetability of cRGDyC-sEVs to U87 cells improved 2.4-fold than natural sEVs. Despite their proneness to be colocalised with endosomes/lysosomes, both Dox@sEVs and Dox@cRGDyC-sEVs showed superior cytotoxicity to U87 GBM cells compared to Dox@Liposomes, particularly Dox@cRGDyC-sEVs. Overall, U87-derived sEVs were successufully conjugated with cRGDyC via a PEG linker, and cRGDyC-sEVs were demonstrated to be a potnetial integrin-targeting drug delivery vehicle for GBM treatment. Graphic abstract.

Delivery of Corn-Derived Nanoparticles with Anticancer Activity to Tumor Tissues by Modification with Polyethylene Glycol for Cancer Therapy

PURPOSE

We recently reported that intratumoral injection of corn-derived nanoparticles (cNPs) affords anticancer activity in tumor-bearing mice. To increase their applicability in cancer therapy, we examined the tissue distribution of cNPs after intravenous injection in mice, modified their surface with polyethylene glycol (PEG) to improve tumor delivery, and examined tissue distribution and anticancer activity of PEG-cNPs in tumor-bearing mice.

METHODS

N-(Carbonyl-methoxypolyethyleneglycol2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG) was added to cNPs by sonication to obtain PEG-cNPs, and the ratio of DSPE-PEG to cNPs was optimized by evaluating the modification efficiency. cNPs and PEG-cNPs were labeled with fluorescent dyes DiO or DiR, and their tissue distribution was subsequently examined after intravenous administration to mice. Finally, we determined the anticancer activity and toxicity of PEG-cNPs.

RESULTS

No detectable fluorescence intensity was observed in mouse serum after intravenous DiR-cNP injection. DSPE-PEG was successfully modified into cNPs, and a PEG:cNPs ratio of 50 was determined as optimal for preparing PEG-cNPs, based on their size and zeta potential. DiO-PEG-cNPs exhibited significantly higher serum concentrations and lower liver accumulation than DiO-cNPs. Moreover, DiR-PEG-cNPs accumulated in tumor tissues of colon26 tumor-bearing mice. Repeated intravenous PEG-cNP injections significantly retarded tumor growth, with no significant hepatotoxicity or nephrotoxicity.

CONCLUSION

Overall, these results indicate that controlling the tissue distribution of cNPs via PEG modification on their surface can be a valuable strategy for developing intravenously injectable cNPs for cancer therapy.

Molecular Docking and Intracellular Translocation of Extracellular Vesicles for Efficient Drug Delivery

Extracellular vesicles (EVs), including exosomes, mediate intercellular communication by delivering their contents, such as nucleic acids, proteins, and lipids, to distant target cells. EVs play a role in the progression of several diseases. In particular, programmed death-ligand 1 (PD-L1) levels in exosomes are associated with cancer progression. Furthermore, exosomes are being used for new drug-delivery systems by modifying their membrane peptides to promote their intracellular transduction via micropinocytosis. In this review, we aim to show that an efficient drug-delivery system and a useful therapeutic strategy can be established by controlling the molecular docking and intracellular translocation of exosomes. We summarise the mechanisms of molecular docking of exosomes, the biological effects of exosomes transmitted into target cells, and the current state of exosomes as drug delivery systems.

A simple approach to re-engineering small extracellular vesicles to circumvent endosome entrapment

Small extracellular vesicles (sEVs) have emerged as attractive drug delivery systems. However, the intracellular release of their cargoes is restricted. This study aimed to develop an efficient approach to re-engineer sEVs by hybridisation with pH-sensitive liposomes (PSLs) and investigate their endosome escape potential. MIA PaCa-2 cell-derived sEVs and PSLs were fused via three methods, and fusion efficiency (FE) was measured using a fluorescence resonance energy transfer assay and nanoparticle tracking analysis. Cellular uptake, intracellular trafficking, and cytotoxicity of doxorubicin-loaded vesicles (Dox@hybrids, Dox@sEVs, and Dox@PSLs) were investigated on MIA PaCa-2 cells. Among the three methods, Ca²⁺-mediated fusion was the simplest and led to a comparable FE with freeze-thaw method, which was significantly higher than PEG₈₀₀₀-mediated fusion. sEVs were more stable after hybridisation with PSLs. Confocal microscopy revealed that the hybrids internalised more efficiently than natural sEVs. While the internalised Dox@sEVs were primarily co-localised with endo/lysosomes even after 8 h, Dox from Dox@hybrids was found to escape from endosomes by 2 h and homogenously distributed in the cytosol before accumulated at nucleus, corresponding to the in vitro pH-responsive release profile. Consequently, Dox@hybrids enhanced cytotoxicity compared with Dox@sEVs, Dox@PSLs, or free drugs. Overall, the biomimetic nanosystem generated by simple Ca²⁺-mediated fusion was more stable and demonstrated higher efficiencies of cellular uptake and endosome escape compared to natural sEVs.

Strategies for persistent retention of macromolecules and nanoparticles in the blood circulation

The enhanced permeability and retention (EPR) effect has been the gold standard in developing drug delivery systems for passive tumor targeting. Although the importance of this concept remains unchanged, some controversies have arisen. In this review, various strategies for tumor targeting using macromolecules and nanoparticles based on the EPR effect are discussed from the viewpoint of pharmacokinetics. Overall, such strategies seek to retain therapeutic material in the blood circulation, which is a key factor for successful targeting. Strategies using macromolecules, including antibody-drug conjugates, serum albumin-based delivery systems, PEGylated recombinant proteins, and stealth liposomes as well as nanoparticle-based strategies such as those based on lipid nanoparticles, and polymeric micelles, have been discussed. The feasibility of small extracellular vesicles, a new class of nanosized delivery carriers, is also discussed.

Therapeutic Strategy of Mesenchymal-Stem-Cell-Derived Extracellular Vesicles as Regenerative Medicine

Extracellular vesicles (EVs) are lipid bilayer membrane particles that play critical roles in intracellular communication through EV-encapsulated informative content, including proteins, lipids, and nucleic acids. Mesenchymal stem cells (MSCs) are pluripotent stem cells with self-renewal ability derived from bone marrow, fat, umbilical cord, menstruation blood, pulp, etc., which they use to induce tissue regeneration by their direct recruitment into injured tissues, including the heart, liver, lung, kidney, etc., or secreting factors, such as vascular endothelial growth factor or insulin-like growth factor. Recently, MSC-derived EVs have been shown to have regenerative effects against various diseases, partially due to the post-transcriptional regulation of target genes by miRNAs. Furthermore, EVs have garnered attention as novel drug delivery systems, because they can specially encapsulate various target molecules. In this review, we summarize the regenerative effects and molecular mechanisms of MSC-derived EVs.

Immunosuppressive Extracellular Vesicles as a Linking Factor in the Development of Tumor and Endometriotic Lesions in the Gynecologic Tract

Both gynecological tumors and endometriosis require for their development a favorable environment, termed in the case of tumors a "pre-metastatic niche" and in case of endometriosis a "pro-endometriotic niche". This is characterized by chronic inflammation and immunosuppression that support the further progression of initial lesions. This microenvironment is established and shaped in the course of a vivid cross-talk between the tumor or endometrial cells with other stromal, endothelial and immune cells. There is emerging evidence that extracellular vesicles (EVs) play a key role in this cellular communication, mediating both in tumors and endometriosis similar immunosuppressive and pro-inflammatory mechanisms. In this review, we discuss the latest findings about EVs as immunosuppressive factors, highlighting the parallels between gynecological tumors and endometriosis. Furthermore, we outline their role as potential diagnostic or prognostic biomarkers as well as their future in therapeutic applications.

Vesicular Ganglioside GM1 From Breast Tumor Cells Stimulated Epithelial-to-Mesenchymal Transition of Recipient MCF-10A Cells

Small extracellular vesicles (sEVs) are a type of membrane structure secreted by cells, which are involved in physiological and pathological processes by participating in intercellular communication. Glycosphingolipids (GSLs) are enriched in sEV and can be delivered to recipient cells. In this study, we found that overexpression of B3GALT4, the glycosyltransferase responsible for ganglioside GM1 synthesis, can induce the epithelial-mesenchymal transition (EMT) process in MCF-10A cells. Moreover, GM1 was verified to be presented on sEV from breast cancer cells. Overexpression of B3GALT4 resulted in elevated vesicular GM1 levels and increased sEV secretion in breast cancer cells. Proteomic analysis revealed that eleven sEV secretion-related proteins were differentially expressed, which might contribute to the altered sEV secretion. Of the identified proteins, 15 oncogenic differentially expressed proteins were documented to be presented in sEV. With the treatment of GM1-enriched sEV from breast cancer cells, the EMT process was induced in recipient non-tumorigenic epithelial MCF-10A cells. Our findings demonstrated that GM1-enriched sEVs derived from breast cancer cells induced the EMT process of recipient cells, which might provide essential information on the biological function of vesicular GM1.

Action Mechanisms of Small Extracellular Vesicles in Inflammaging

The accumulation process of proinflammatory components in the body due to aging influences intercellular communication and is known as inflammaging. This biological mechanism relates the development of inflammation to the aging process. Recently, it has been reported that small extracellular vesicles (sEVs) are mediators in the transmission of paracrine senescence involved in inflammatory aging. For this reason, their components, as well as mechanisms of action of sEVs, are relevant to develop a new therapy called senodrugs (senolytics and senomorphic) that regulates the intercellular communication of inflammaging. In this review, we include the most recent and relevant studies on the role of sEVs in the inflammatory aging process and in age-related diseases such as cancer and type 2 diabetes.

Calcium Enabled Remote Loading of a Weak Acid Into pH-sensitive Liposomes and Augmented Cytosolic Delivery to Cancer Cells via the Proton Sponge Effect

While delivery of chemotherapeutics to cancer cells by nanomedicines can improve therapeutic outcomes, many fail due to the low drug loading (DL), poor cellular uptake and endosomal entrapment. This study investigated the potential to overcome these limitations using pH-sensitive liposomes (PSL) empowered by the use of calcium acetate. An acidic dinitrobenzamide mustard prodrug SN25860 was used as a model drug, with non pH-sensitive liposomes (NPSL) as a reference. Calcium acetate as a remote loading agent allowed to engineer PSL- and NPSL-SN25860 with DL of > 31.1% (w/w). The IC₅₀ of PSL-SN25860 was 21- and 141-fold lower than NPSL and free drug, respectively. At 48 h following injection of PSL-SN25860, NPSL-SN25860 and the free drug, drug concentrations in EMT6-nfsB murine breast tumors were 56.3 µg/g, 6.76 µg/g and undetectable (< 0.015 µg/g), respectively (n = 3). Meanwhile, the ex vivo tumor clonogenic assay showed 9.1%, 19.4% and 42.7% cell survival in the respective tumors. Live-cell imaging and co-localization analysis suggested endosomal escape was accomplished by destabilization of PSL followed by release of Ca²⁺ in endosomes allowing induction of a proton sponge effect. Subsequent endosomal rupture was observed approximately 30 min following endocytosis of PSL containing Ca²⁺. Additionally, calcium in liposomes promoted internalization of both PSL and NPSL. Taken together, this study demonstrated multifaceted functions of calcium acetate in promoting drug loading into liposomes, cellular uptake, and endosomal escape of PSL for efficient cytoplasmic drug delivery. The results shed light on designing nano-platforms for cytoplasmic delivery of various therapeutics.

News about Therapies of Alzheimer’s Disease: Extracellular Vesicles from Stem Cells Exhibit Advantages Compared to Other Treatments

Upon its discovery, Alzheimer’s, the neurodegenerative disease that affects many millions of patients in the world, remained without an effective therapy. The first drugs, made available near the end of last century, induced some effects, which remained only marginal. More promising effects are now present, induced by two approaches. Blockers of the enzyme BACE-1 induce, in neurons and glial cells, decreased levels of Aβ, the key peptide of the Alzheimer’s disease. If administered at early AD steps, the BACE-1 blockers preclude further development of the disease. However, they have no effect on established, irreversible lesions. The extracellular vesicles secreted by mesenchymal stem cells induce therapy effects analogous, but more convenient, than the effects of their original cells. After their specific fusion to target cells, the action of these vesicles depends on their ensuing release of cargo molecules, such as proteins and many miRNAs, active primarily on the cell cytoplasm. Operationally, these vesicles exhibit numerous advantages: they exclude, by their accurate selection, the heterogeneity of the original cells; exhibit molecular specificity due to their engineering and drug accumulation; and induce effective actions, mediated by variable concentrations of factors and molecules and by activation of signaling cascades. Their strength is reinforced by their combination with various factors and processes. The recent molecular and operations changes, induced especially by the stem cell target cells, result in encouraging and important improvement of the disease. Their further development is expected in the near future.

Engineering Exosomes Endowed with Targeted Delivery of Triptolide for Malignant Melanoma Therapy

Malignant melanoma is considered the most aggressive skin carcinoma with invasive growth patterns. Triptolide (TPL) possesses various biological and pharmacological activities involved in cancer treatment. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce cancer cell apoptosis by binding to DR5 highly expressed on cancer cells. Exosomes are natural nanomaterials with low immunogenicity, nontoxicity, and excellent biocompatibility and have been extensively used as emerging delivery vectors for diverse therapeutic cargos. Herein, a delivery system based on TRAIL-engineered exosomes (TRAIL-Exo) for loading TPL for targeted therapy against malignant melanoma is proposed and systematically investigated. Our results showed that TRAIL-Exo/TPL could improve tumor targetability, enhance cellular uptake, inhibit proliferation, invasion, and migration, and induce apoptosis of A375 cells through activating the extrinsic TRAIL pathway and the intrinsic mitochondrial pathway in vitro. Moreover, intravenous injection of TRAIL-Exo/TPL significantly suppressed tumor progression and reduced the toxicity of TPL in the melanoma nude mouse model. Together, our research presents a novel strategy for high-efficiency exosome-based drug-delivery nanocarriers and provides an alternative dimension for developing a promising approach with synergistic therapeutic efficacy and targeting capacity for melanoma treatment.

CRISPR/Cas9: Principle, Applications, and Delivery through Extracellular Vesicles

The establishment of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) technology for eukaryotic gene editing opened up new avenues not only for the analysis of gene function but also for therapeutic interventions. While the original methodology allowed for targeted gene disruption, recent technological advancements yielded a rich assortment of tools to modify genes and gene expression in various ways. Currently, clinical applications of this technology fell short of expectations mainly due to problems with the efficient and safe delivery of CRISPR/Cas9 components to living organisms. The targeted in vivo delivery of therapeutic nucleic acids and proteins remain technically challenging and further limitations emerge, for instance, by unwanted off-target effects, immune reactions, toxicity, or rapid degradation of the transfer vehicles. One approach that might overcome many of these limitations employs extracellular vesicles as intercellular delivery devices. In this review, we first introduce the CRISPR/Cas9 system and its latest advancements, outline major applications, and summarize the current state of the art technology using exosomes or microvesicles for transporting CRISPR/Cas9 constituents into eukaryotic cells.

The role and application of small extracellular vesicles in gastric cancer

Gastric cancer (GC) is a common tumour that affects humans worldwide, is highly malignant and has a poor prognosis. Small extracellular vesicles (sEVs), especially exosomes, are nanoscale vesicles released by various cells that deliver bioactive molecules to recipient cells, affecting their biological characteristics, changing the tumour microenvironment and producing long-distance effects. In recent years, many studies have clarified the mechanisms by which sEVs function with regard to the initiation, progression, angiogenesis, metastasis and chemoresistance of GC. These molecules can function as mediators of cell-cell communication in the tumour microenvironment and might affect the efficacy of immunotherapy. Due to their unique physiochemical characteristics, sEVs show potential as effective antitumour vaccines as well as drug carriers. In this review, we summarize the roles of sEVs in GC and highlight the clinical application prospects in the future.