Targeted Delivery of Exosomes Armed with Anti-Cancer Therapeutics

Decoding the secrets of small extracellular vesicle communications: exploring the inhibition of vesicle-associated pathways and interception strategies for cancer treatment

Cancer disease is the second leading cause of death worldwide. In 2023, about 2 million new cancer cases and 609,820 cancer deaths are projected to occur in the United States. The driving forces of cancer progression and metastasis are widely varied and comprise multifactorial events. Although there is significant success in treating cancer, patients still present with tumors at advanced stages. Therefore, the discovery of novel oncologic pathways has been widely developed. Tumor cells communicate with each other through small extracellular vesicles (sEVs), which contribute to tumor-stromal interaction and promote tumor growth and metastasis. sEV-specific inhibitors are being investigated as a next-generation cancer therapy. A literature search was conducted to discuss different options for targeting sEV pathways in cancer cells. However, there are some challenges that need to be addressed in targeting sEVs: i) specificity and toxicity of sEV inhibitor, ii) targeted delivery of sEV inhibitors, iii) combination of sEV inhibitors with current standard chemotherapy to improve patients' clinical outcomes, and iv) data reproducibility and applicability at distinct levels of the disease. Despite these challenges, sEV inhibitors have immense potential for effectively treating cancer patients.

Research Advances of Engineered Exosomes as Drug Delivery Carrier

Exosomes are nanoscale vesicles secreted by living cells that have similar membrane composition to parental cells and carry a variety of proteins, lipids, and nucleic acids. Therefore, exosomes have certain biological activities and play an important role in intercellular communication. On the basis of its potential as a carrier for drug delivery systems, exosomes have been engineered to compensate for the shortage of natural exosomes through various engineering strategies for improving drug delivery efficiency, enhancing targeting to tissues and organs, and extending the circulating half-life of exosomes. This review focuses on the engineered exosomes loading drugs through different strategies, discussions on exosome surface modification strategies, and summarizes the advantages and disadvantages of different strategies. In addition, this review provides an overview of the recent applications of engineered exosomes in a number of refractory and relapsable diseases. This review has the potential to provide a reference for further research and development of engineered exosomes.

Bacteriophage as cargo and its application in nanomedicine

Bacteriophages are viruses that infect the bacteria. However, different studies conducted on the same display a wide range of applications in terms of therapeutic purposes. The structure of a bacteriophage includes the head (site for the storage of its genetic material) and a tail (serves the purpose of detection, ligand-receptor binding and insertion of the genetic material into the host organism). The head being a storehouse of genetic material, the contents of the same are often manipulated for therapeutic purposes. In some cases, these bacteriophages are modified as virus like particles (VLPs), which are employed as carriers for transportation of the desired components to the target site, thereby being reliable alternatives for therapeutic purposes. The distinctive properties of these VLPs include their biocompatibility, abundant space for accommodation of desired components, bio processivity, target specificity, does not interfere with the on-going metabolic processes; thereby being agents of choice for various therapeutic purposes. The bacteriophages play significant roles in delivery of certain components thereby enhancing their therapeutic applications. These include biomolecules such as enzymes, peptide-based drugs, CRISPR along with others. Apart from this, bacteriophage targeted delivery has also shown promising results in cancer treatments and vaccination strategies. Bacteriophages are therefore, promising delivery agents and can be opted for delivery of either single or combination of compounds in future treatment strategies.

Salivary Exosomes in Health and Disease: Future Prospects in the Eye

Exosomes are a group of vesicles that package and transport DNA, RNA, proteins, and lipids to recipient cells. They can be derived from blood, saliva, urine, and/or other biological tissues. Their impact on several diseases, such as neurodegenerative, autoimmune, and ocular diseases, have been reported, but not fully unraveled. The exosomes that are derived from saliva are less studied, but offer significant advantages over exosomes from other sources, due to their accessibility and ease of collection. Thus, their role in the pathophysiology of diseases is largely unknown. In the context of ocular diseases, salivary exosomes have been under-utilized, thus creating an enormous gap in the literature. The current review discusses the state of exosomes research on systemic and ocular diseases and highlights the role and potential of salivary exosomes as future ocular therapeutic vehicles.

Engineered anti-EGFRvIII targeted exosomes induce apoptosis in glioblastoma multiforme

BACKGROUND

The drug delivery for treatment of glioblastoma multiforme (GBM) has been unsatisfactory mainly due to the drug resistance and low targeting efficiency. The selective targeting of GBM cells and using a cocktail of therapeutic agents to synergistically induce apoptosis may help enhance the drug delivery.

METHODS

In this study, mesenchymal stem cells (MSCs) were engineered to produce exosomes, i.e. nanosized natural vesicles presenting anti-EGFRvIII (ab139) antibody on their surface while encapsulating two apoptosis-inducing gene therapy agents, i.e. cytosine deaminase (CDA) and miR-34a. Exosomes were characterised for their size, morphology, protein content and markers using dynamic light scattering and nanoparticle tracking analysis, cryo-TEM, Western blotting, respectively. miR-34a overexpression and Lamp2-ab139 protein expression were analysed using real-time PCR and flow cytometry, respectively. The armed exosomes were delivered to EGFRvIII positive GBM cells (U87EGFRvIII) as well as wild type cell line (U87), which was EGFRvIII negative. Apoptosis was quantified using flow cytometry in both EGFRvIII negative and positive U87 cells, receiving one gene therapy agent (either CDA or miR-34a) or a combination of them (CDAmiR).

RESULTS

Spherical shape exosomes with an average diameter of 110 nm and a membrane thickness of 6.5 nm were isolated from MSCs. Lamp2-ab139 was successfully expressed on the surface of transfected cells and their secreted exosomes. Induced apoptosis rates was significantly higher in U87EGFRvIII cells than for U87 cells, indicating selectivity. The cell death rate was 6%, 9% and 12% in U87, 13%, 21% and 40% in U87EGFRvIII cells for CDA, miR-34a and CDAmiR treatment respectively, showing a higher apoptosis rate in the cells receiving both drugs compared to when single therapy was applied.

CONCLUSION

The experimental findings clearly show the improved apoptosis rate of GBM cells when treated by engineered exosomes armed with two gene therapy agents and targeted towards EGFRvIII antigen.

A Meta-analysis on the Effectiveness of Extracellular Vesicles as Nanosystems for Targeted Delivery of Anticancer Drugs

While the efficacy of anticancer drugs is hampered by low bioavailability and systemic toxicity, the uncertainty remains whether encapsulation of these drugs into natural nanovesicles such as extracellular vesicles (EVs) could improve controlled drug release and efficacy for targeted tumor therapy. Thus, we performed a meta-analysis for studies reporting the efficacy of EVs as nanosystems to deliver drugs and nucleic acid, protein, and virus (NPV) to tumors using the random-effects model. The electronic search of articles was conducted through Cochrane, PubMed, Scopus, Science Direct, and Clinical Trials Registry from inception up till September 2022. The pooled summary estimate and 95% confidence interval of tumor growth inhibition, survival, and tumor targeting were obtained to assess the efficacy. The search yielded a total of 119 studies that met the inclusion criteria having only 1 clinical study. It was observed that the drug-loaded EV was more efficacious than the free drug in reducing tumor volume and weight with the standardized mean difference (SMD) of -1.99 (95% CI: -2.36, -1.63; p < 0.00001) and -2.12 (95% CI: -2.48, -1.77; p < 0.00001). Similarly, the mean estimate of tumor volume and weight for NPV were the following: SMD: -2.30, 95% CI: -3.03, -1.58; p < 0.00001 and SMD: -2.05, 95% CI: -2.79, -1.30; p < 0.00001. Treatment of tumors with EV-loaded anticancer agents also prolonged survival (HR: 0.15, 95% CI: 0.10, 0.22, p < 0.00001). Furthermore, EVs significantly delivered drugs to tumors as revealed by the higher concentration at the tumor site (SMD: -2.73, 95% CI: -3.77, -1.69; p < 0.00001). This meta-analysis revealed that EV-loaded drugs and NPV performed significantly better in tumor growth inhibition with improved survival than the free anticancer agents, suggesting EVs as safe nanoplatforms for targeted tumor therapy.

Efficient cell death mediated by bioengineered killer extracellular vesicles

Extracellular vesicles (EVs) are biological vehicles that are thought to mediate cell-cell communication via the transfer of biomolecules from donor to acceptor cells. Repurposing those natural vesicles into therapeutics delivery vectors is a high priority challenge for translational science. Here we engineer donor cells to produce copious amount of fusogenic EVs loaded with the catalytic domain of the Diphteria Toxin, known to trigger cell death through protein synthesis inhibition. We show that, when incubated with cancer acceptor cells, these Killer EVs block protein synthesis and lead to cell death. This proof of concept establishes the efficacy of Killer EVs in vitro, and suggests that further development may lead to tumor ablation in vivo, expanding the existing cancer therapeutics arsenal.

Future applications of exosomes delivering resolvins and cytokines in facilitating diabetic foot ulcer healing

Type 2 diabetes mellitus (T2DM) increases the risk of many lethal and debilitating conditions. Among them, foot ulceration due to neuropathy, vascular disease, or trauma affects the quality of life of millions in the United States and around the world. Physiological wound healing is stalled in the inflammatory phase by the chronicity of inflammation without proceeding to the resolution phase. Despite advanced treatment, diabetic foot ulcers (DFUs) are associated with a risk of amputation. Thus, there is a need for novel therapies to address chronic inflammation, decreased angiogenesis, and impaired granulation tissue formation contributing to the non-healing of DFUs. Studies have shown promising results with resolvins (Rv) and anti-inflammatory therapies that resolve inflammation and enhance tissue healing. But many of these studies have encountered difficulty in the delivery of Rv in terms of efficiency, tissue targetability, and immunogenicity. This review summarized the perspective of optimizing the therapeutic application of Rv and cytokines by pairing them with exosomes as a novel strategy for targeted tissue delivery to treat non-healing chronic DFUs. The articles discussing the T2DM disease state, current research on Rv for treating inflammation, the role of Rv in enhancing wound healing, and exosomes as a delivery vehicle were critically reviewed to find support for the proposition of using Rv and exosomes in combination for DFUs therapy. The literature reviewed suggests the beneficial role of Rv and exosomes and exosomes loaded with anti-inflammatory agents as promising therapeutic agents in ulcer healing.

Exosome-Based Smart Drug Delivery Tool for Cancer Theranostics

Exosomes are the phospholipid-membrane-bound subpopulation of extracellular vesicles derived from the plasma membrane. The main activity of exosomes is cellular communication. In cancer, exosomes play an important rolefrom two distinct perspectives, one related to carcinogenesis and the other as theragnostic and drug delivery tools. The outer phospholipid membrane of Exosome improves drug targeting efficiency. . Some of the vital features of exosomes such as biocompatibility, low toxicity, and low immunogenicity make it a more exciting drug delivery system. Exosome-based drug delivery is a new innovative approach to cancer treatment. Exosome-associated biomarker analysis heralded a new era of cancer diagnostics in a more specific way. This Review focuses on exosome biogenesis, sources, isolation, interrelationship with cancer and exosome-related cancer biomarkers, drug loading methods, exosome-based biomolecule delivery, advances and limitations of exosome-based drug delivery, and exosome-based drug delivery in clinical settings studies. The exosome-based understanding of cancer will change the diagnostic and therapeutic approach in the future.

Hybrid exosomes, exosome-like nanovesicles and engineered exosomes for therapeutic applications

Exosomes are endosome-derived nanovesicles involved in cellular communication. They are natural nanocarriers secreted by various cells, making them suitable candidates for diverse drug delivery and therapeutic applications from a material standpoint. They have a phospholipid bilayer decorated with functional molecules and an enclosed parental matrix, which has attracted interest in developing designer/hybrid engineered exosome nanocarriers. The structural versatility of exosomes allows the modification of their original configuration using various methods, including genetic engineering, chemical procedures, physical techniques, and microfluidic technology, to load exosomes with additional cargo for expanded biomedical applications. Exosomes show enormous potential for overcoming the limitations of conventional nanoparticle-based techniques in targeted therapy. This review highlights the exosome sources, characteristics, state of the art in the field of hybrid exosomes, exosome-like nanovesicles and engineered exosomes as potential cargo delivery vehicles for therapeutic applications.

Mucus-derived exosome-like vesicles from the Spanish slug (Arion vulgaris): taking advantage of invasive pest species in biotechnology

The slug Arion vulgaris has attracted major attention as one of the worst invasive herbivore pests in Europe and is renowned for the stiff mucus it secretes for locomotion. In this study we focused on the isolation and characterisation of extracellular vesicles, specifically exosomes and exosome-like vesicles, from Arion secretions. We developed a method for slug mucus collection and subsequent vesicle isolation by ultracentrifugation. The isolated vesicles with an average diameter of ~ 100 nm carry abundant proteins and short RNAs, as well as adhesion molecules similar to mammalian galectins. We demonstrated that the slug extracellular vesicles are internalised by plant cells and human cancer cells in in vitro assays and are loadable by bioactive compounds, which makes them an interesting tool for utilisation in biotechnology.

Advances in Purification, Modification, and Application of Extracellular Vesicles for Novel Clinical Treatments

Extracellular vesicles (EV) are membrane vesicles surrounded by a lipid bilayer membrane and include microvesicles, apoptotic bodies, exosomes, and exomeres. Exosome-encapsulated microRNAs (miRNAs) released from cancer cells are involved in the proliferation and metastasis of tumor cells via angiogenesis. On the other hand, mesenchymal stem cell (MSC) therapy, which is being employed in regenerative medicine owing to the ability of MSCs to differentiate into various cells, is due to humoral factors, including messenger RNA (mRNA), miRNAs, proteins, and lipids, which are encapsulated in exosomes derived from transplanted cells. New treatments that advocate cell-free therapy using MSC-derived exosomes will significantly improve clinical practice. Therefore, using highly purified exosomes that perform their original functions is desirable. In this review, we summarized advances in the purification, modification, and application of EVs as novel strategies to treat some diseases.

Cell-Derived Vesicles for mRNA Delivery

The clinical translation of messenger mRNA (mRNA)-based therapeutics requires safe and effective delivery systems. Although considerable progress has been made on the development of mRNA delivery systems, many challenges, such as the dose-limiting toxicity and specific delivery to extrahepatic tissues, still remain. Cell-derived vesicles, a type of endogenous membranous particle secreted from living cells, can be leveraged to load mRNA during or after their biogenesis. Currently, they have received increasing interest for mRNA delivery due to their natural origin, good biocompatibility, cell-specific tropism, and unique ability to cross physiological barriers. In this review, we provide an overview of recent advances in the naturally occurring mRNA delivery platforms and their biomedical applications. Furthermore, the future perspectives on clinical translation of cell-derived vesicles have been discussed.

Osteosarcoma-Derived Exosomes as Potential PET Imaging Nanocarriers for Lung Metastasis

Lung metastases represent the most adverse clinical factor and rank as the leading cause of osteosarcoma-related death. Nearly 80% of patients present lung micrometastasis at diagnosis not detected with current clinical tools. Herein, an exosome (EX)-based imaging tool is developed for lung micrometastasis by positron emission tomography (PET) using osteosarcoma-derived EXs as natural nanocarriers of the positron-emitter copper-64 (⁶⁴ Cu). Exosomes are isolated from metastatic osteosarcoma cells and functionalized with the macrocyclic chelator NODAGA for complexation with ⁶⁴ Cu. Surface functionalization has no effect on the physicochemical properties of EXs, or affinity for donor cells and endows them with favorable pharmacokinetics for in vivo studies. Whole-body PET/magnetic resonance imaging (MRI) images in xenografted models show a specific accumulation of ⁶⁴ Cu-NODAGA-EXs in metastatic lesions as small as 2-3 mm or in a primary tumor, demonstrating the exquisite tropism of EXs for homotypic donor cells. The targetability for lung metastasis is also observed by optical imaging using indocyanine green (ICG)-labeled EXs and D-luciferin-loaded EXs. These findings show that tumor-derived EXs hold great potential as targeted imaging agents for the noninvasive detection of small lung metastasis by PET. This represents a step forward in the biomedical application of EXs in imaging diagnosis with increased translational potential.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Multi-Omics Integrative Approach of Extracellular Vesicles: A Future Challenging Milestone

In the era of multi-omic sciences, dogma on singular cause-effect in physio-pathological processes is overcome and system biology approaches have been providing new perspectives to see through. In this context, extracellular vesicles (EVs) are offering a new level of complexity, given their role in cellular communication and their activity as mediators of specific signals to target cells or tissues. Indeed, their heterogeneity in terms of content, function, origin and potentiality contribute to the cross-interaction of almost every molecular process occurring in a complex system. Such features make EVs proper biological systems being, therefore, optimal targets of omic sciences. Currently, most studies focus on dissecting EVs content in order to either characterize it or to explore its role in various pathogenic processes at transcriptomic, proteomic, metabolomic, lipidomic and genomic levels. Despite valuable results being provided by individual omic studies, the categorization of EVs biological data might represent a limit to be overcome. For this reason, a multi-omic integrative approach might contribute to explore EVs function, their tissue-specific origin and their potentiality. This review summarizes the state-of-the-art of EVs omic studies, addressing recent research on the integration of EVs multi-level biological data and challenging developments in EVs origin.