3D Cell Cultures as Prospective Models to Study Extracellular Vesicles in Cancer

Circulating exosomes in pediatric obstructive sleep apnea with or without neurocognitive deficits and their effects on a 3D-blood-brain barrier spheroid model

Obstructive sleep apnea (OSA) in children is linked to cognitive impairments, potentially due to blood-brain barrier (BBB) dysfunction. Exosomes, small vesicles released by most cells, reflect cellular changes. This study examined the effects of exosomes from children with OSA, with or without cognitive deficits, on neurovascular unit (NVU) models. Twenty-six children were categorized into three groups: healthy controls (Cont, n = 6), OSA without cognitive deficits (OSA-NG, n = 10), and OSA with neurocognitive deficits (OSA-POS, n = 10). Plasma exosomes were characterized and applied to human 3D NVU spheroids for 24 h. Barrier integrity, permeability, and angiogenesis were assessed using trans-endothelial electrical resistance (TEER), tight junction integrity, and tube formation assays. Single-nucleus RNA sequencing (snRNA-seq) and bioinformatics, including CellChat analysis, identified intercellular signaling pathways. Results showed that exosomes from OSA-POS children disrupted TEER, increased permeability, and impaired ZO1 staining in spheroids, compared to the other groups. Both OSA-POS and OSA-NG exosomes increased permeability in NVU cells in monolayer and microfluidic BBB models. snRNA-seq analysis further revealed distinct cell clusters and pathways associated with the different groups. This 3D NVU spheroid model provides a robust platform to study BBB properties and the role of exosomes in OSA. These findings suggest that integrating snRNA-seq with exosome studies can uncover mechanisms underlying neurocognitive dysfunction in pediatric OSA, potentially leading to personalized therapeutic approaches.

Mesenchymal Stem Cells-Derived Small Extracellular Vesicles and Their Validation as a Promising Treatment for Chondrosarcoma in a 3D Model in Vitro

Chondrosarcomas (CHS) constitute approximately 20% of all primary malignant bone tumors, characterized by a slow growth rate with initial manifestation of few signs and symptoms. These malignant cartilaginous neoplasms, particularly those with dedifferentiated histological subtypes, pose significant therapeutic challenges, as they exhibit high resistance to both radiation and chemotherapy. Ranging from relatively benign, low-grade tumors (grade I) to aggressive high-grade tumors with the potential for lung metastases and a grim prognosis, there is a critical need for innovative diagnostic and therapeutic approaches, particularly for patients with more aggressive forms. Herein, small extracellular vesicles (sEVs) derived from mesenchymal stem cells are presented as an efficient nanodelivery tool to enhance drug penetration in an in vitro 3D model of CHS. Employing high-pressure homogenization (HPH), we achieved unprecedented encapsulation efficiency of doxorubicin (DXR) in sEVs derived from mesenchymal stem cells (MSC-EVs). Subsequently, a comparative analysis between free DXR and MSC-EVs encapsulated with DXR (DXR-MSC-EVs) was conducted to assess their penetration and uptake efficacy in the 3D model. The results unveiled a higher incidence of necrotic cells and a more pronounced toxic effect with DXR-MSC-EVs compared to DXR alone. This underscores the remarkable ability of MSC-EVs to deliver drugs in complex environments, highlighting their potential application in the treatment of aggressive CHS.

Effects of Hydrogels on Mesenchymal Stem/Stromal Cells Paracrine Activity and Extracellular Vesicles Production

Mesenchymal stem/stromal cells (MSCs) are a valuable source of paracrine factors, as they have a remarkable secretory capacity, and there is a sizeable knowledge base to develop industrial and clinical production protocols. Promising cell-free approaches for tissue regeneration and immunomodulation are driving research towards secretome applications, among which extracellular vesicles (EVs) are steadily gaining attention. However, the manufacturing and application of EVs is limited by insufficient yields, knowledge gaps, and low standardization. Facing these limitations, hydrogels represent a versatile three-dimensional (3D) culture platform that can incorporate extracellular matrix (ECM) components to mimic the natural stem cell environment in vitro; via these niche-mimicking properties, hydrogels can regulate MSCs' morphology, adhesion, proliferation, differentiation and secretion capacities. However, the impact of the hydrogel's architectural, biochemical and biomechanical properties on the production of EVs remains poorly understood, as the field is still in its infancy and the interdependency of culture parameters compromises the comparability of the studies. Therefore, this review summarizes and discusses the reported effects of hydrogel encapsulation and culture on the secretion of MSC-EVs. Considering the effects of cell-material interactions on the overall paracrine activity of MSCs, we identify persistent challenges from low standardization and process control, and outline future paths of research, such as the synergic use of hydrogels and bioreactors to enhance MSC-EV generation.

Cancer-on-chip: a breakthrough organ-on-a-chip technology in cancer cell modeling

Cancer remains one of the leading causes of death worldwide. The unclear molecular mechanisms and complex in vivo microenvironment of tumors make it difficult to clarify the nature of cancer and develop effective treatments. Therefore, the development of new methods to effectively treat cancer is urgently needed and of great importance. Organ-on-a-chip (OoC) systems could be the breakthrough technology sought by the pharmaceutical industry to address ever-increasing research and development costs. The past decade has seen significant advances in the spatial modeling of cancer therapeutics related to OoC technology, improving physiological exposition criteria. This article aims to summarize the latest achievements and research results of cancer cell treatment simulated in a 3D microenvironment using OoC technology. To this end, we will first discuss the OoC system in detail and then demonstrate the latest findings of the cancer cell treatment study by Ooc and how this technique can potentially optimize better modeling of the tumor. The prospects of OoC systems in the treatment of cancer cells and their advantages and limitations are also among the other points discussed in this study.

Extracellular vesicles derived-microRNAs predicting enzalutamide-resistance in 3D spheroid prostate Cancer model

Enzalutamide (ENZ) has emerged as a major treatment advance in castration-resistant prostate cancer (CRPC) patients; however the development of resistance remains a key challenge. The extracellular vesicles (VEs)-derived miRNAs play crucial roles tumor microenvironment cell communication, thereby influencing resistance mechanisms. Considering the urgent need for molecular biomarkers to monitor ENZ response and predict resistance, we intend to identify an EV-derived miRNA profile associated with ENZ resistance using an innovative 3D-spheroid in vitro model. Through the generation of this model, we provide a comprehensive platform for elucidating the molecular alterations involved in the process. An in vitro model of ENZ resistance was established through continuous exposure of LNCaP to increasing ENZ concentrations. A screening of 799 miRNAs from resistant and normal LNCaP cells were quantified. A bioinformatic analysis was performed using miRTarbase and Cytoscape and top 5 overexpressed miRNAs were selected, that will be analyzed in extracellular vesicles derived from ENZ resistance 3D spheroid models. We identified 12 up- and 13 downregulated miRNAs in LNCaP 30 μM ENZ cells compare to LNCaP·In silico analysis led to the construction of a 76 proteins cluster and functional enrichment revealed terms like PI3K/AKT, TFG-β and FOXO. hsa-miR-22-3p was significantly decreased at 5 and 20 μM ENZ concentration intracellularly, but significantly increased at 20 μM ENZ in EVs. hsa-miR-221-3p and miR-222-3p were upregulated in all concentrations both intracellularly and in EVs. The developed 3D-spheroid model effectively replicated the ENZ resistance to ENZ in an AR-independent manner, underscoring the importance of EVs-derived miRNAs in this adaptive process.

Global Literature Analysis of Tumor Organoid and Tumor-on-Chip Research

Background: Tumor organoid and tumor-on-chip (ToC) platforms replicate aspects of the anatomical and physiological states of tumors. They, therefore, serve as models for investigating tumor microenvironments, metastasis, and immune interactions, especially for precision drug testing. To map the changing research diversity and focus in this field, we performed a quality-controlled text analysis of categorized academic publications and clinical studies. Methods: Previously, we collected metadata of academic publications on organoids or organ-on-chip platforms from PubMed, Web of Science, Scopus, EMBASE, and bioRxiv, published between January 2011 and June 2023. Here, we selected documents from this metadata corpus that were computationally determined as relevant to tumor research and analyzed them using an in-house text analysis algorithm. Additionally, we collected and analyzed metadata from ClinicalTrials.gov of clinical studies related to tumor organoids or ToC as of March 2023. Results and Discussion: From 3551 academic publications and 139 clinical trials, we identified 55 and 24 tumor classes modeled as tumor organoids and ToC models, respectively. The research was particularly active in neural and hepatic/pancreatic tumor organoids, as well as gastrointestinal, neural, and reproductive ToC models. Comparative analysis with cancer statistics showed that lung, lymphatic, and cervical tumors were under-represented in tumor organoid research. Our findings also illustrate varied research topics, including tumor physiology, therapeutic approaches, immune cell involvement, and analytical techniques. Mapping the research geographically highlighted the focus on colorectal cancer research in the Netherlands, though overall the specific research focus of countries did not reflect regional cancer prevalence. These insights not only map the current research landscape but also indicate potential new directions in tumor model research.

Extracellular vesicles biogenesis and uptake concepts: A comprehensive guide to studying host-pathogen communication

The study of host-pathogen interactions has increased considerably in recent decades. This intercellular communication has been mediated by extracellular vesicles (EVs) that play an important role during the interaction. EVs are particles of lipid bilayer and described in different types of cells, eukaryotic or prokaryotic. Depending on their biogenesis they are described as exosomes (derived from multivesicular bodies) and microvesicles (derived from the plasma membrane). The EVs carry biomolecules, including nucleic acids, lipids, and proteins that can be released or internalized by other cells in different pathways (endocytosis, macropinocytosis, phagocytosis, or membrane fusion) in the process described as uptake. The balance between biogenesis and uptake of EVs could modify physiological and pathophysiological processes of the cell. This review is focusing on the dynamic roles of release and capture of EVs during host-pathogen interaction. We also do a critical analysis of methodologies for obtaining and analyzing EVs. Finally, we draw attention to critical points to be considered in EV biogenesis and uptake studies.

Advancing cancer therapeutics: Integrating scalable 3D cancer models, extracellular vesicles, and omics for enhanced therapy efficacy

Cancer remains as one of the highest challenges to human health. However, anticancer drugs exhibit one of the highest attrition rates compared to other therapeutic interventions. In part, this can be attributed to a prevalent use of in vitro models with limited recapitulative potential of the in vivo settings. Three dimensional (3D) models, such as tumor spheroids and organoids, offer many research opportunities to address the urgent need in developing models capable to more accurately mimic cancer biology and drug resistance profiles. However, their wide adoption in high-throughput pre-clinical studies is dependent on scalable manufacturing to support large-scale therapeutic drug screenings and multi-omic approaches for their comprehensive cellular and molecular characterization. Extracellular vesicles (EVs), which have been emerging as promising drug delivery systems (DDS), stand to significantly benefit from such screenings conducted in realistic cancer models. Furthermore, the integration of these nanomedicines with 3D cancer models and omics profiling holds the potential to deepen our understanding of EV-mediated anticancer effects. In this chapter, we provide an overview of the existing 3D models used in cancer research, namely spheroids and organoids, the innovations in their scalable production and discuss how omics can facilitate the implementation of these models at different stages of drug testing. We also explore how EVs can advance drug delivery in cancer therapies and how the synergy between 3D cancer models and omics approaches can benefit in this process.

Three-Dimensional Hepatocyte Spheroids: Model for Assessing Chemotherapy in Hepatocellular Carcinoma

BACKGROUND

Three-dimensional cellular models provide a more comprehensive representation of in vivo cell properties, encompassing physiological characteristics and drug susceptibility.

METHODS

Primary hepatocytes were seeded in ultra-low attachment plates to form spheroids, with or without tumoral cells. Spheroid structure, cell proliferation, and apoptosis were analyzed using histological staining techniques. In addition, extracellular vesicles were isolated from conditioned media by differential ultracentrifugation. Spheroids were exposed to cytotoxic drugs, and both spheroid growth and cell death were measured by microscopic imaging and flow cytometry with vital staining, respectively.

RESULTS

Concerning spheroid structure, an active outer layer forms a boundary with the media, while the inner core comprises a mass of cell debris. Hepatocyte-formed spheroids release vesicles into the extracellular media, and a decrease in the concentration of vesicles in the culture media can be observed over time. When co-cultured with tumoral cells, a distinct distribution pattern emerges over the primary hepatocytes, resulting in different spheroid conformations. Tumoral cell growth was compromised upon antitumoral drug challenges.

CONCLUSIONS

Treatment of mixed spheroids with different cytotoxic drugs enables the characterization of drug effects on both hepatocytes and tumoral cells, determining drug specificity effects on these cell types.

Extracellular Vesicles in Breast Cancer: From Intercellular Communication to Therapeutic Opportunities

Breast cancer, a multifaceted and heterogeneous disease, poses significant challenges in terms of understanding its intricate resistance mechanisms and devising effective therapeutic strategies. This review provides a comprehensive overview of the intricate landscape of extracellular vesicles (EVs) in the context of breast cancer, highlighting their diverse subtypes, biogenesis, and roles in intercellular communication within the tumour microenvironment (TME). The discussion spans various aspects, from EVs and stromal cells in breast cancer to their influence on angiogenesis, immune response, and chemoresistance. The impact of EV production in different culture systems, including two dimensional (2D), three dimensional (3D), and organoid models, is explored. Furthermore, this review delves into the therapeutic potential of EVs in breast cancer, presenting emerging strategies such as engineered EVs for gene delivery, nanoplatforms for targeted chemotherapy, and disrupting tumour derived EVs as a treatment approach. Understanding these complex interactions of EV within the breast cancer milieu is crucial for identifying resistance mechanisms and developing new therapeutic targets.

Co-Delivery of an Innovative Organoselenium Compound and Paclitaxel by pH-Responsive PCL Nanoparticles to Synergistically Overcome Multidrug Resistance in Cancer

In this study, we designed the association of the organoselenium compound 5'-Seleno-(phenyl)-3'-(ferulic-amido)-thymidine (AFAT-Se), a promising innovative nucleoside analogue, with the antitumor drug paclitaxel, in poly(ε-caprolactone) (PCL)-based nanoparticles (NPs). The nanoprecipitation method was used, adding the lysine-based surfactant, 77KS, as a pH-responsive adjuvant. The physicochemical properties presented by the proposed NPs were consistent with expectations. The co-nanoencapsulation of the bioactive compounds maintained the antioxidant activity of the association and evidenced greater antiproliferative activity in the resistant/MDR tumor cell line NCI/ADR-RES, both in the monolayer/two-dimensional (2D) and in the spheroid/three-dimensional (3D) assays. Hemocompatibility studies indicated the safety of the nanoformulation, corroborating the ability to spare non-tumor 3T3 cells and human mononuclear cells of peripheral blood (PBMCs) from cytotoxic effects, indicating its selectivity for the cancerous cells. Furthermore, the synergistic antiproliferative effect was found for both the association of free compounds and the co-encapsulated formulation. These findings highlight the antitumor potential of combining these bioactives, and the proposed nanoformulation as a potentially safe and effective strategy to overcome multidrug resistance in cancer therapy.

Extracellular vesicles secreted by 3D tumor organoids are enriched for immune regulatory signaling biomolecules compared to conventional 2D glioblastoma cell systems

Background

Newer 3D culturing approaches are a promising way to better mimic the in vivo tumor microenvironment and to study the interactions between the heterogeneous cell populations of glioblastoma multiforme. Like many other tumors, glioblastoma uses extracellular vesicles as an intercellular communication system to prepare surrounding tissue for invasive tumor growth. However, little is known about the effects of 3D culture on extracellular vesicles. The aim of this study was to comprehensively characterize extracellular vesicles in 3D organoid models and compare them to conventional 2D cell culture systems.

Methods

Primary glioblastoma cells were cultured as 2D and 3D organoid models. Extracellular vesicles were obtained by precipitation and immunoaffinity, with the latter allowing targeted isolation of the CD9/CD63/CD81 vesicle subpopulation. Comprehensive vesicle characterization was performed and miRNA expression profiles were generated by smallRNA-sequencing. In silico analysis of differentially regulated miRNAs was performed to identify mRNA targets and corresponding signaling pathways. The tumor cell media and extracellular vesicle proteome were analyzed by high-resolution mass spectrometry.

Results

We observed an increased concentration of extracellular vesicles in 3D organoid cultures. Differential gene expression analysis further revealed the regulation of twelve miRNAs in 3D tumor organoid cultures (with nine miRNAs down and three miRNAs upregulated). MiR-23a-3p, known to be involved in glioblastoma invasion, was significantly increased in 3D. MiR-7-5p, which counteracts glioblastoma malignancy, was significantly decreased. Moreover, we identified four miRNAs (miR-323a-3p, miR-382-5p, miR-370-3p, miR-134-5p) located within the DLK1-DIO3 domain, a cancer-associated genomic region, suggesting a possible importance of this region in glioblastoma progression. Overrepresentation analysis identified alterations of extracellular vesicle cargo in 3D organoids, including representation of several miRNA targets and proteins primarily implicated in the immune response.

Conclusion

Our results show that 3D glioblastoma organoid models secrete extracellular vesicles with an altered cargo compared to corresponding conventional 2D cultures. Extracellular vesicles from 3D cultures were found to contain signaling molecules associated with the immune regulatory signaling pathways and as such could potentially change the surrounding microenvironment towards tumor progression and immunosuppressive conditions. These findings suggest the use of 3D glioblastoma models for further clinical biomarker studies as well as investigation of new therapeutic options.

Research progress of exosomes in the angiogenesis of digestive system tumour

Malignant tumours of the digestive system cover a wide range of diseases that affect the health of people to a large extent. Angiogenesis is indispensable in the development, and metastasis of tumours, mainly in two ways: occupation or formation. Vessels can provide nutrients, oxygen, and growth factors for tumours to encourage growth and metastasis, so cancer progression depends on simultaneous angiogenesis. Recently, exosomes have been proven to participate in the angiogenesis of tumours. They influence angiogenesis by binding to tyrosine kinase receptors (VEGFR)-1, VEGFR-2, and VEGFR-3 with different affinities, regulating Yap-VEGF pathway, Akt pathway or other signaling pathway. Additionally, exosomes are potential therapeutic vectors that can deliver many types of cargoes to different cells. In this review, we summarize the roles of exosomes in the angiogenesis of digestive system tumours and highlight the clinical application prospects, directly used as targers or delivery vehicles, in antiangiogenic therapy.

Modelling the complex nature of the tumor microenvironment: 3D tumor spheroids as an evolving tool

Cancer remains a serious burden in society and while the pace in the development of novel and more effective therapeutics is increasing, testing platforms that faithfully mimic the tumor microenvironment are lacking. With a clear shift from animal models to more complex in vitro 3D systems, spheroids emerge as strong options in this regard. Years of development have allowed spheroid-based models to better reproduce the biomechanical cues that are observed in the tumor-associated extracellular matrix (ECM) and cellular interactions that occur in both a cell-cell and cell-ECM manner. Here, we summarize some of the key cellular interactions that drive tumor development, progression and invasion, and how successfully are these interactions recapitulated in 3D spheroid models currently in use in the field. We finish by speculating on future advancements in the field and on how these can shape the relevance of spherical 3D models for tumor modelling.

Doxorubicin-loaded NK exosomes enable cytotoxicity against triple-negative breast cancer spheroids

Objectives

Natural killer (NK) cells are the most professional innate immune cells that initiate extracellular apoptosis via cytotoxic granules in malignant cells. Antitumoral properties of NK-derived exosomes (Exos) are attributed to their parent cells. Loading drugs into Exos as a carrier can enhance their effect and enable targeted delivery. In the present study, we aim to deliver Doxorubicin (DOX) to the breast cancer spheroids by NK-Exos.

Materials and Methods

Peripheral blood mononuclear cells (PBMC) were used to harvest NK cells, and NK-Exos were isolated from NK cell expansion medium using an Exo-spinTM kit. DOX was loaded via the ultrasonication method. AO/EtBr, Annexin/PI, DAPI, MTT, and spheroids of human breast cancer were used to track the cytotoxic effect of DOX-NK-Exos. The colony formation assay, scratch and transwell assays, Real-Time PCR for p53 and VEGF-A, and WB for protein expression were also performed.

Results

When compared to free DOX, all viability tests validated the inhibitory effects of DOX-NK-Exos. The obtained results indicated that DOX-NK-Exos selectively reduced tumor cell viability and spared fibroblast and MCF-10A as noncancerous cells. Long after spheroid treatment, DOX-NK-Exos' remarkable effect persisted.

Conclusion

Human breast carcinoma mass treated with DOX-NK-Exos underwent apoptosis and showed a strong inhibitory effect on proliferation. Thus, they can reduce the side effects of chemotherapeutics and can be used as drug carriers with selective toxicity. Additionally, the additive action of this combination formula results in a more severe loss in cell viability.

Engineered exosomes derived from stem cells: a new brain-targeted strategy

INTRODUCTION

Using engineered exosomes produced from stem cells is an experimental therapeutic approach for treating brain diseases. According to reports, preclinical research has demonstrated notable neurogenesis and angiogenesis effects using modified stem cell-derived exosomes. These biological nanoparticles have a variety of anti-apoptotic, anti-inflammatory, and antioxidant properties that make them very promising for treating nervous system disorders.

AREAS COVERED

This review examines different ways to enhance the delivery of modified stem cell-derived exosomes, how they infiltrate the blood-brain barrier (BBB), and how they facilitate their access to the brain. We would also like to determine whether these nanoparticles have the most significant transmission rates through BBB when targeting brain lesions.

EXPERT OPINION

Using engineered stem cell-derived exosomes for treating brain disorders has generated considerable attention toward clinical research and application. However, stem cell-derived exosomes lack consistency, and their mechanisms of action are uncertain. Therefore, upcoming research needs to prioritize examining the underlying mechanisms and strategies via which these nanoparticles combat neurological disorders.

Engineering Biomimetic Nanoparticles through Extracellular Vesicle Coating in Cancer Tissue Models

Using nanoparticles (NPs) in drug delivery has exhibited promising therapeutic potential in various cancer types. Nevertheless, several challenges must be addressed, including the formation of the protein corona, reduced targeting efficiency and specificity, potential immune responses, and issues related to NP penetration and distribution within 3-dimensional tissues. To tackle these challenges, we have successfully integrated iron oxide nanoparticles into neuroblastoma-derived extracellular vesicles (EVs) using the parental labeling method. We first developed a tissue-engineered (TE) neuroblastoma model, confirming the viability and proliferation of neuroblastoma cells for at least 12 days, supporting its utility for EV isolation. Importantly, EVs from long-term cultures exhibited no differences compared to short-term cultures. Concurrently, we designed Rhodamine (Rh) and Polyacrylic acid (PAA)-functionalized magnetite nanoparticles (Fe3O4@PAA-Rh) with high crystallinity, purity, and superparamagnetic properties (average size: 9.2 ± 2.5 nm). We then investigated the internalization of Fe3O4@PAA-Rh nanoparticles within neuroblastoma cells within the TE model. Maximum accumulation was observed overnight while ensuring robust cell viability. However, nanoparticle internalization was low. Taking advantage of the enhanced glucose metabolism exhibited by cancer cells, glucose (Glc)-functionalized nanoparticles (Fe3O4@PAA-Rh-Glc) were synthesized, showing superior cell uptake within the 3D model without inducing toxicity. These glucose-modified nanoparticles were selected for parental labeling of the TE models, showing effective NP encapsulation into EVs. Our research introduces innovative approaches to advance NP delivery, by partially addressing the challenges associated with 3D systems, optimizing internalization, and enhancing NP stability and specificity through EV-based carriers. Also, our findings hold the promise of more precise and effective cancer therapies while minimizing potential side effects.

Can Organoid Model Reveal a Key Role of Extracellular Vesicles in Tumors? A Comprehensive Review of the Literature

Extracellular vesicles (EVs) are small membrane-bound vesicles that are released by cells into the extracellular environment. The role of EVs in tumors has been extensively studied, and they have been shown to play a crucial role in tumor growth, progression, and metastasis. Past research has mainly used 2D-cultured cell line models to investigate the role of EVs in tumors, which poorly simulate the tumor microenvironment. Organoid technology has gradually matured in recent years. Organoids are similar in composition and behavior to physiological cells and have the potential to recapitulate the architecture and function of the original tissue. It has been widely used in organogenesis, drug screening, gene editing, precision medicine and other fields. The integration of EVs and organoids has the potential to revolutionize the field of cancer research and represents a promising avenue for advancing our understanding of cancer biology and the development of novel therapeutic strategies. Here, we aimed to present a comprehensive overview of studies using organoids to study EVs in tumors.

Extracellular vesicles from the CNS play pivotal roles in neuroprotection and neurodegeneration: lessons from in vitro experiments

Intercellular communication between diverse cell types is crucial for the maintenance of the central nervous system, and exosomes have been shown to play an important role in this process. Exosomes are small extracellular vesicles (EVs) that are released by all cell types and carry cargoes that can elicit downstream effects in recipient cells. Exosomal communication in the central nervous system has been implicated in many neurodegenerative diseases, ranging from Alzheimer's disease to major depressive disorder. Though there remain many unknowns in the field of EV biology, in vitro experiments can provide many insights into their potential roles in health and disease. In this review, we discuss the findings of many in vitro EV experiments, with a focus on the potential roles in regulating cell viability, inflammation, oxidative stress, and neurite integrity in the central nervous system.

Production and Utility of Extracellular Vesicles with 3D Culture Methods

In recent years, extracellular vesicles (EVs) have emerged as promising biomarkers, cell-free therapeutic agents, and drug delivery carriers. Despite their great clinical potential, poor yield and unscalable production of EVs remain significant challenges. When using 3D culture methods, such as scaffolds and bioreactors, large numbers of cells can be expanded and the cell environment can be manipulated to control the cell phenotype. This has been employed to successfully increase the production of EVs as well as to enhance their therapeutic effects. The physiological relevance of 3D cultures, such as spheroids, has also provided a strategy for understanding the role of EVs in the pathogenesis of several diseases and to evaluate their role as tools to deliver drugs. Additionally, 3D culture methods can encapsulate EVs to achieve more sustained therapeutic effects as well as prevent premature clearance of EVs to enable more localised delivery and concentrated exosome dosage. This review highlights the opportunities and drawbacks of different 3D culture methods and their use in EV research.

Advancement of Organoid Technology in Regenerative Medicine

Purpose

Organoids are three-dimensional cultures of stem cells in an environment similar to the body's extracellular matrix. This is also a novel development in the realm of regenerative medicine. Stem cells can begin to develop into 3D structures by modifying signaling pathways. To form organoids, stem cells are transplanted into the extracellular matrix. Organoids have provided the required technologies to reproduce human tissues. As a result, it might be used in place of animal models in scientific study. The key goals of these investigations are research into viral and genetic illnesses, malignancies, and extracellular vesicles, pharmaceutical discovery, and organ transplantation. Organoids can help pave the road for precision medicine through genetic editing, pharmaceutical development, and cell therapy.

Methods

PubMed, Google Scholar, and Scopus were used to search for all relevant papers written in English (1907-2021). The study abstracts were scrutinized. Studies on the use of stem-cell-derived organoids in regenerative medicine, organoids as 3D culture models for EVs analysis, and organoids for precision medicine were included. Articles with other irrelevant aims, meetings, letters, commentaries, congress and conference abstracts, and articles with no available full texts were excluded.

Results

According to the included studies, organoids have various origins, types, and applications in regenerative and precision medicine, as well as an important role in studying extracellular vesicles.

Conclusion

Organoids are considered a bridge that connects preclinical studies to clinical ones. However, the lack of a standardized protocol and other barriers addressed in this review, hinder the vast use of this technology.

Lay Summary

Organoids are 3D stem cell propagations in biological or synthetic scaffolds that mimic ECM to allow intercellular or matrix-cellular crosstalk. Because these structures are similar to organs in the body, they can be used as research models. Organoids are medicine's future hope for organ transplantation, tumor biobank formation, and the development of precision medicine. Organoid models can be used to study cell-to-cell interactions as well as effective factors like inflammation and aging. Bioengineering technologies are also used to define the size, shape, and composition of organoids before transforming them into precise structures. Finally, the importance of organoid applications in regenerative medicine has opened a new window for a better understanding of biological research, as discussed in this study.

Focus on organoids: cooperation and interconnection with extracellular vesicles - Is this the future of in vitro modeling?

Organoids are simplified in vitro model systems of organs that are used for modeling tissue development and disease, drug screening, cell therapy, and personalized medicine. Despite considerable success in the design of organoids, challenges remain in achieving real-life applications. Organoids serve as unique and organized groups of micro physiological systems that are capable of self-renewal and self-organization. Moreover, they exhibit similar organ functionality(ies) as that of tissue(s) of origin. Organoids can be designed from adult stem cells, induced pluripotent stem cells, or embryonic stem cells. They consist of most of the important cell types of the desired tissue/organ along with the topology and cell-cell interactions that are highly similar to those of an in vivo tissue/organ. Organoids have gained interest in human biomedical research, as they demonstrate high promise for use in basic, translational, and applied research. As in vitro models, organoids offer significant opportunities for reducing the reliance and use of experimental animals. In this review, we will provide an overview of organoids, as well as those intercellular communications mediated by extracellular vesicles (EVs), and discuss the importance of organoids in modeling a tumor immune microenvironment (TIME). Organoids can also be exploited to develop a better understanding of intercellular communications mediated by EVs. Also, organoids are useful in mimicking TIME, thereby offering a better-controlled environment for studying various associated biological processes and immune cell types involved in tumor immunity, such as T-cells, macrophages, dendritic cells, and myeloid-derived suppressor cells, among others.

Bench to Bedside: New Therapeutic Approaches with Extracellular Vesicles and Engineered Biomaterials for Targeting Therapeutic Resistance of Cancer Stem Cells

Cancer has recently been the second leading cause of death worldwide, trailing only cardiovascular disease. Cancer stem cells (CSCs), represented as tumor-initiating cells (TICs), are mainly liable for chemoresistance and disease relapse due to their self-renewal capability and differentiating capacity into different types of tumor cells. The intricate molecular mechanism is necessary to elucidate CSC's chemoresistance properties and cancer recurrence. Establishing efficient strategies for CSC maintenance and enrichment is essential to elucidate the mechanisms and properties of CSCs and CSC-related therapeutic measures. Current approaches are insufficient to mimic the in vivo chemical and physical conditions for the maintenance and growth of CSC and yield unreliable research results. Biomaterials are now widely used for simulating the bone marrow microenvironment. Biomaterial-based three-dimensional (3D) approaches for the enrichment of CSC provide an excellent promise for future drug discovery and elucidation of molecular mechanisms. In the future, the biomaterial-based model will contribute to a more operative and predictive CSC model for cancer therapy. Design strategies for materials, physicochemical cues, and morphology will offer a new direction for future modification and new methods for studying the CSC microenvironment and its chemoresistance property. This review highlights the critical roles of the microenvironmental cues that regulate CSC function and endow them with drug resistance properties. This review also explores the latest advancement and challenges in biomaterial-based scaffold structure for therapeutic approaches against CSC chemoresistance. Since the recent entry of extracellular vesicles (EVs), cell-derived nanostructures, have opened new avenues of investigation into this field, which, together with other more conventionally studied signaling pathways, play an important role in cell-to-cell communication. Thus, this review further explores the subject of EVs in-depth. This review also discusses possible future biomaterial and biomaterial-EV-based models that could be used to study the tumor microenvironment (TME) and will provide possible therapeutic approaches. Finally, this review concludes with potential perspectives and conclusions in this area.

Cancer extracellular vesicles, tumoroid models, and tumor microenvironment

Cancer extracellular vesicles (EVs), or exosomes, promote tumor progression through enhancing tumor growth, initiating epithelial-to-mesenchymal transition, remodeling the tumor microenvironment, and preparing metastatic niches. Three-dimensionally (3D) cultured tumoroids / spheroids aim to reproduce some aspects of tumor behavior in vitro and show increased cancer stem cell properties. These properties are transferred to their EVs that promote tumor growth. Moreover, recent tumoroid models can be furnished with aspects of the tumor microenvironment, such as vasculature, hypoxia, and extracellular matrix. This review summarizes tumor tissue culture and engineering platforms compatible with EV research. For example, the combination experiments of 3D-tumoroids and EVs have revealed multifunctional proteins loaded in EVs, such as metalloproteinases and heat shock proteins. EVs or exosomes are able to transfer their cargo molecules to recipient cells, whose fates are often largely altered. In addition, the review summarizes approaches to EV labeling technology using fluorescence and luciferase, useful for studies on EV-mediated intercellular communication, biodistribution, and metastatic niche formation.

In vivo imaging of EVs in zebrafish: New perspectives from "the waterside"

To harmoniously coordinate the activities of all its different cell types, a multicellular organism critically depends on intercellular communication. One recently discovered mode of intercellular cross-talk is based on the exchange of "extracellular vesicles" (EVs). EVs are nano-sized heterogeneous lipid bilayer vesicles enriched in a variety of biomolecules that mediate short- and long-distance communication between different cells, and between cells and their environment. Numerous studies have demonstrated important aspects pertaining to the dynamics of their release, their uptake, and sub-cellular fate and roles in vitro. However, to demonstrate these and other aspects of EV biology in a relevant, fully physiological context in vivo remains challenging. In this review we analyze the state of the art of EV imaging in vivo, focusing in particular on zebrafish as a promising model to visualize, study, and characterize endogenous EVs in real-time and expand our understanding of EV biology at cellular and systems level.

Induction of Apoptosis by Isoalantolactone in Human Hepatocellular Carcinoma Hep3B Cells through Activation of the ROS-Dependent JNK Signaling Pathway

Isoalantolactone (IALT) is one of the isomeric sesquiterpene lactones isolated from the roots of Inula helenium L. IALT is known to possess various biological and pharmacological activities, but its anti-cancer mechanisms are not well understood. The aim of the present study was to investigate the anti-proliferative effects of IALT in human hepatocellular carcinoma (HCC) cells and to evaluate the potential anti-cancer mechanisms. Our results demonstrated that IALT treatment concentration-dependently suppressed the cell survival of HCC Hep3B cells, which was associated with the induction of apoptosis. IALT increased the expression of death-receptor-related proteins, activated caspases, and induced Bid truncation, subsequently leading to cleavage of poly (ADP-ribose) polymerase. In addition, IALT contributed to the cytosolic release of cytochrome c by destroying mitochondrial integrity, following an increase in the Bax/Bcl-2 expression ratio. However, IALT-mediated growth inhibition and apoptosis were significantly attenuated in the presence of a pan-caspase inhibitor, suggesting that IALT induced caspase-dependent apoptosis in Hep3B cells. Moreover, IALT activated the mitogen-activated protein kinases signaling pathway, and the anti-cancer effect of IALT was significantly diminished in the presence of a potent c-Jun N-terminal kinase (JNK) inhibitor. IALT also improved the generation of intracellular reactive oxygen species (ROS), whereas the ROS inhibitor significantly abrogated IALT-induced growth reduction, apoptosis, and JNK activation. Furthermore, ROS-dependent apoptosis was revealed as a mechanism involved in the anti-cancer activity of IALT in a 3D multicellular tumor spheroid model of Hep3B cells. Taken together, our findings indicate that IALT exhibited anti-cancer activity in HCC Hep3B cells by inducing ROS-dependent activation of the JNK signaling pathway.

Extracellular vesicles in anti-tumor immunity

To what extent extracellular vesicles (EVs) can impact anti-tumor immune responses has only started to get unraveled. Their nanometer dimensions, their growing number of subtypes together with the difficulties in defining their origin hamper their investigation. The existence of tumor cell lines facilitated advance in cancer EV understanding, while capturing information about phenotypes and functions of immune cell EVs in this context is more complex. The advent of immunotherapy with immune checkpoint inhibitors has further deepened the need to dissect the impact of EVs during immune activation and response, not least to contribute unraveling and preventing the generation of resistance occurring in the majority of patients. Here we discuss the factors that influence anddrive the immune response in cancer patients in the context of cancer therapeutics and the roles or possible functions that EVs can have in this scenario. With immune cell-derived EVs as leitmotiv, we will journey from EV discovery and subtypes through physiological and pathological functions, from similarities with tumor EVs to measures to revert detrimental consequences on immune responses to cancer.

3D Models as an Adjunct for Models in Studying Alzheimer’s Disease

Alzheimer’s disease (AD) is one of the most common causes of dementia. Disease progression is marked by cognitive decline and memory impairment due to neurodegenerative processes in the brain stemming from amyloid-β (Aβ) deposition and formation of neurofibrillary tangles. Pathogenesis in AD is dependent on two main neurological processes: formation of intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein and deposition of extracellular senile Aβ peptides. Given the nature of the disease, the pathology and progression of AD in vivo in humans have been difficult to study in vivo. To this degree, models can help to study the disease pathogenesis, biochemistry, immunological functions, genetics, and potential pharmacotherapy. While animal and two-dimensional (2D) cell culture models have facilitated significant progress in studying the disease, more recent application of novel three-dimensional (3D) culture models has exhibited several advantages. Herein, we describe a brief background of AD, and how current animal, 2D, and 3D models facilitate the study of this disease and associated therapeutics.

In Vitro 3D Cultures to Model the Tumor Microenvironment

Simple Summary

Tumor stroma is known to significantly influence cancer initiation and progression. In the last decade, 3D cell cultures have shown potential in modeling the tumor microenvironment. This review summarizes the main features of current 3D models, shedding light on their importance in the study of cancer biology and treatment.

Abstract

It is now well established that the tumor microenvironment plays a key role in determining cancer growth, metastasis and drug resistance. Thus, it is fundamental to understand how cancer cells interact and communicate with their stroma and how this crosstalk regulates disease initiation and progression. In this setting, 3D cell cultures have gained a lot of interest in the last two decades, due to their ability to better recapitulate the complexity of tumor microenvironment and therefore to bridge the gap between 2D monolayers and animal models. Herein, we present an overview of the 3D systems commonly used for studying tumor–stroma interactions, with a focus on recent advances in cancer modeling and drug discovery and testing.

Importance of stem cell culture conditions for their derived extracellular vesicles therapeutic effect

Stem cell-derived extracellular vesicles (EVs) could be enhanced by modifying specific in vitro parameters when culturing their originating stem cells. Controlling stem cell growth conditions with physical properties, oxygen tension and media preconditioning with soluble factors may influence EVs biogenesis and EVs biological function as well. Unfortunately, many misconceptions and methodological issues have hampered the progress in understanding the biological properties of EVs. In this review we will first discuss the major concerns involved in a suitable EVs production from stem cell culture. Then, we will describe the current techniques for EV isolation, focusing on their advantages and disadvantages, as well as their impact on EVs yield, recovery and functionality. Standardization of the methodology is a prerequisite to compare, to validate and to improve the reliability and credibility of all the different findings reported for the development of EV-based therapeutics.