Mesenchymal stem cells deliver synthetic microRNA mimics to glioma cells and glioma stem cells and inhibit their cell migration and self-renewal

A game of hide-and-seek: how extracellular vesicles evade the immune system

Extracellular vesicles (EVs) are heterogeneously sized, cell-derived nanoparticles operating as proficient mediators of intercellular communication. They are produced by normal as well as diseased cells and carry a variety of cargo. While the molecular details of EV biology have been worked out over the past two decades, one question that continues to intrigue many is how are EVs able to evade the phagocytic immune cells while also being effectively internalized by the target cell or tissue. While some of the components that facilitate this process have started to be identified, many mechanisms are yet to be dissected. This review summarises some of the key mechanisms that cancer cell-derived and viral infected cell-derived EVs utilize to evade the immune system. It will discuss the diverse cloaking mechanisms, in the form of membrane proteins and cargo content that these EVs utilize to enhance pathogenesis. Further, it will highlight the different strategies that have been used to design EVs to escape the immune system, thereby increasing their circulation time with no major toxic effects in vivo. An understanding of the potential EV components that allow better immune evasion can be used to bioengineer EVs with better circulation times for therapeutic purposes.

Mesenchymal Stem Cells in Cancer Therapy

The mesenchymal stem/stromal cells (MSCs) are multipotent cells that were initially discovered in the bone marrow in the late 1960s but have so far been discovered in almost all tissues of the body. The multipotent property of MSCs enables them to differentiate into various cell types and lineages, such as adipocytes, chondrocytes, and osteocytes. The immunomodulation capacity and tumor-targeting features of MSCs made their use crucial for cell-based therapies in cancer treatment, yet limited advancement could be observed in translational medicine prospects due to the need for more information regarding the controversial roles of MSCs in crosstalk tumors. In this review, we discuss the therapeutic potential of MSCs, the controversial roles played by MSCs in cancer progression, and the anticancer therapeutic strategies that are in association with MSCs. Finally, the clinical trials designed for the direct use of MSCs for cancer therapy or for their use in decreasing the side effects of other cancer therapies are also mentioned in this review to evaluate the current status of MSC-based cancer therapies.

Therapeutic Effects of Exosomal miRNA-4731-5p from Adipose Tissue-Derived Stem Cells on Human Glioblastoma Cells

BACKGROUND AND AIM

Several microRNAs (miRNAs) are differentially expressed and serve as tumor suppressors in glioblastoma (GBM). The present study aimed to elucidate the function of exosomal microRNA-4731-5p (miR-4731-5p) from adipose tissue-derived mesenchymal stem cells (AD-MSCs) in the activity of human GBM cell lines.

METHOD

First, GBM-related miRNAs, their expression, and potential target genes and cytokines of miR-4731-5p were identified using bioinformatic datasets. Subsequently, purified AD-MSCs were transfected with a miRNA-4731-5p expression plasmid, and exosomes were isolated and characterized. Next, the transfection process was confirmed and the 50% inhibitory concentration (IC50) of the overexpressed exosomal miRNA-4731-5p was inhibited for cancer cells. The probable anticancer action of exosomal miRNA-4731-5p on U-87 and U-251 GBM cell lines was verified by flow cytometry, DAPI staining, cell cycle, real-time PCR, and wound healing assays.

RESULTS

A concentration of 50 ng/mL of miRNA-4731-5p-transfected exosomes was the safe dose for anticancer settings. The results showed that the exosomal miR-4731-5p exerted an inhibitory effect on the cell cycle and migration and induced apoptosis in GBM cell lines by regulating the phosphoinositide-3-kinase-AKT (PI3K-AKT) and nuclear factor-kB (NF-kB) signaling pathways.

CONCLUSION

This study reveals that the expression of exosomal miRNA-4731-5p has favorable antitumor properties for the treatment of GBM cell lines and may be a fundamental therapeutic option for this type of brain tumor.

The potential of exosomes as a new therapeutic strategy for glioblastoma

Glioblastoma (GBM) stands for the most common and aggressive type of brain tumour in adults. It is highly invasive, which explains its short rate of survival. Little is known about its risk factors, and current therapy is still ineffective. Hence, efforts are underway to develop novel and effective treatment approaches against this type of cancer. Exosomes are being explored as a promising strategy for conveying and delivering therapeutic cargo to GBM cells. They can fuse with the GBM cell membrane and, consequently, serve as delivery systems in this context. Due to their nanoscale size, exosomes can cross the blood-brain barrier (BBB), which constitutes a significant hurdle to most chemotherapeutic drugs used against GBM. They can subsequently inhibit oncogenes, activate tumour suppressor genes, induce immune responses, and control cell growth. However, despite representing a promising tool for the treatment of GBM, further research and clinical studies regarding exosome biology, engineering, and clinical applications still need to be completed. Here, we sought to review the application of exosomes in the treatment of GBM through an in-depth analysis of the scientific and clinical studies on the entire process, from the isolation and purification of exosomes to their design and transformation into anti-oncogenic drug delivery systems. Surface modification of exosomes to enhance BBB penetration and GBM-cell targeting is also a topic of discussion.

Endovascular surgical neuro-oncology: advancing a new subspecialty

Endovascular surgical neuro-oncology is a relatively new subspecialty which uses endovascular neuro-interventional techniques for the management of nervous system tumors and tumor-related vascular conditions. Although there are several endovascular procedures that are widely available as standard-of-care diagnostic and treatment adjuncts, there has been a renewed interest to explore endovascular approaches as a means for selective intra-arterial delivery of therapeutic agents to nervous system tumors, including methods for opening the blood brain and blood tumor barriers. In this review, we discuss the historical development of various forms of endovascular intra-arterial treatment for tumors over the past 40 years, summarize endovascular approaches that are currently being employed, and highlight current clinical trials.

Contents of exosomes derived from adipose tissue and their regulation on inflammation, tumors, and diabetes

Adipose tissue (AT) serves as an energy-capacitive organ and performs functions involving paracrine- and endocrine-mediated regulation via extracellular vesicles (EVs) secretion. Exosomes, a subtype of EVs, contain various bioactive molecules with regulatory effects, such as nucleic acids, proteins, and lipids. AT-derived exosomes (AT-exos) include exosomes derived from various cells in AT, including adipocytes, adipose-derived stem cells (ADSCs), macrophages, and endothelial cells. This review aimed to comprehensively evaluate the impacts of different AT-exos on the regulation of physiological and pathological processes. The contents and functions of adipocyte-derived exosomes and ADSC-derived exosomes are compared simultaneously, highlighting their similarities and differences. The contents of AT-exos have been shown to exert complex regulatory effects on local inflammation, tumor dynamics, and insulin resistance. Significantly, differences in the cargoes of AT-exos have been observed among diabetes patients, obese individuals, and healthy individuals. These differences could be used to predict the development of diabetes mellitus and as therapeutic targets for improving insulin sensitivity and glucose tolerance. However, further research is needed to elucidate the underlying mechanisms and potential applications of AT-exos.

MiR-338-5p, a novel metastasis-related miRNA, inhibits triple-negative breast cancer progression by targeting the ETS1/NOTCH1 axis

Breast cancer ranks as the most prevalent cancer globally, surpassing lung cancer, with recurrence/metastasis to be its main account for the cancer-related mortality. MicroRNAs (miRNAs) participate critically in various physiological and pathological processes through posttranscriptional regulation of downstream genes. Our preliminary findings identified miR-338-5p, potentially linked to metastasis in breast cancer, a previously unexplored area. Analysis of the GSE38867 dataset revealed the decreased miR-338-5p expression in metastatic breast cancer compared to normal tissues. Cellular function experiments and a xenograft tumor model demonstrated the inhibitory function of miR-338-5p on the progression of breast cancer in vitro and in vivo. Furthermore, it downregulated the expression of mesenchymal biomarkers and NOTCH1 significantly. With the predicting targets of miR-338-5p and transcription factors of the NOTCH1 gene, coupled with dual luciferase reporter assays, it is identified ETS1 as the interactor between miR-338-5p and NOTCH1. In breast cancer tissues, as well as in our xenograft tumor model, expression of ETS1 and NOTCH1 was positively correlated using immunohistochemical staining. This study reports, for the first time, on the miR-338-5p/ETS1/NOTCH1 axis and its pivotal role in breast cancer proliferation and metastasis. These findings propose a novel therapeutic strategy for breast cancer patients and lays a foundation for its clinical detection and treatment evaluation.

Bioengineered Mesenchymal Stem/Stromal Cells in Anti-Cancer Therapy: Current Trends and Future Prospects

Mesenchymal stem/stromal cells (MSCs) are one of the most widely used cell types in advanced therapies due to their therapeutic potential in the regulation of tissue repair and homeostasis, and immune modulation. However, their use in cancer therapy is controversial: they can inhibit cancer cell proliferation, but also potentially promote tumour growth by supporting angiogenesis, modulation of the immune milieu and increasing cancer stem cell invasiveness. This opposite behaviour highlights the need for careful and nuanced use of MSCs in cancer treatment. To optimize their anti-cancer effects, diverse strategies have bioengineered MSCs to enhance their tumour targeting and therapeutic properties or to deliver anti-cancer drugs. In this review, we highlight the advanced uses of MSCs in cancer therapy, particularly as carriers of targeted treatments due to their natural tumour-homing capabilities. We also discuss the potential of MSC-derived extracellular vesicles to improve the efficiency of drug or molecule delivery to cancer cells. Ongoing clinical trials are evaluating the therapeutic potential of these cells and setting the stage for future advances in MSC-based cancer treatment. It is critical to identify the broad and potent applications of bioengineered MSCs in solid tumour targeting and anti-cancer agent delivery to position them as effective therapeutics in the evolving field of cancer therapy.

Current Strategies and Therapeutic Applications of Mesenchymal Stem Cell-Based Drug Delivery

Mesenchymal stem cells (MSCs) have emerged as a promising approach for drug delivery strategies because of their unique properties. These strategies include stem cell membrane-coated nanoparticles, stem cell-derived extracellular vesicles, immunomodulatory effects, stem cell-laden scaffolds, and scaffold-free stem cell sheets. MSCs offer advantages such as low immunogenicity, homing ability, and tumor tropism, making them ideal for targeted drug delivery systems. Stem cell-derived extracellular vesicles have gained attention for their immune properties and tumor-homing abilities, presenting a potential solution for drug delivery challenges. The relationship between MSC-based drug delivery and the self-renewal and differentiation capabilities of MSCs lies in the potential of engineered MSCs to serve as effective carriers for therapeutic agents while maintaining their intrinsic properties. MSCs exhibit potent immunosuppressive functions in MSC-based drug delivery strategies. Stem cell-derived EVs have low immunogenicity and strong therapeutic potential for tissue repair and regeneration. Scaffold-free stem cell sheets represent a cutting-edge approach in regenerative medicine, offering a versatile platform for tissue engineering and regeneration across different medical specialties. MSCs have shown great potential for clinical applications in regenerative medicine because of their ability to differentiate into various cell types, secrete bioactive factors, and modulate immune responses. Researchers are exploring these innovative approaches to enhance drug delivery efficiency and effectiveness in treating various diseases.

PAQR4 oncogene: a novel target for cancer therapy

Despite decades of basic and clinical research and trials of promising new therapies, cancer remains a major cause of morbidity and mortality due to the emergence of drug resistance to anticancer drugs. These resistance events have a very well-understood underlying mechanism, and their therapeutic relevance has long been recognized. Thus, drug resistance continues to be a major obstacle to providing cancer patients with the intended "cure". PAQR4 (Progestin and AdipoQ Receptor Family Member 4) gene is a recently identified novel protein-coding gene associated with various human cancers and acts through different signaling pathways. PAQR4 has a significant influence on multiple proteins that may regulate various gene expressions and may develop chemoresistance. This review discusses the roles of PAQR4 in tumor immunity, carcinogenesis, and chemoresistance. This paper is the first review, discussing PAQR4 in the pathogenesis of cancer. The review further explores the PAQR4 as a potential target in various malignancies.

Extracellular vesicles as tools and targets in therapy for diseases

Extracellular vesicles (EVs) are nano-sized, membranous structures secreted into the extracellular space. They exhibit diverse sizes, contents, and surface markers and are ubiquitously released from cells under normal and pathological conditions. Human serum is a rich source of these EVs, though their isolation from serum proteins and non-EV lipid particles poses challenges. These vesicles transport various cellular components such as proteins, mRNAs, miRNAs, DNA, and lipids across distances, influencing numerous physiological and pathological events, including those within the tumor microenvironment (TME). Their pivotal roles in cellular communication make EVs promising candidates for therapeutic agents, drug delivery systems, and disease biomarkers. Especially in cancer diagnostics, EV detection can pave the way for early identification and offers potential as diagnostic biomarkers. Moreover, various EV subtypes are emerging as targeted drug delivery tools, highlighting their potential clinical significance. The need for non-invasive biomarkers to monitor biological processes for diagnostic and therapeutic purposes remains unfulfilled. Tapping into the unique composition of EVs could unlock advanced diagnostic and therapeutic avenues in the future. In this review, we discuss in detail the roles of EVs across various conditions, including cancers (encompassing head and neck, lung, gastric, breast, and hepatocellular carcinoma), neurodegenerative disorders, diabetes, viral infections, autoimmune and renal diseases, emphasizing the potential advancements in molecular diagnostics and drug delivery.

miRNAs Delivery for Cancer-associated Fibroblasts' Activation and Drug Resistance in Cancer Microenvironment

Cancer-associated fibroblasts (CAFs) as a major component of cancer stroma contribute to diverse procedures of most solid tumors and might be a targeted cancer therapy approach. Their specified features, related signaling pathways, distinct biomarkers, and sub-populations need to be deciphered. There is a need for CAF extraction or induction for in vitro investigations. Some miRNAs could activate CAF-like phenotype and they also interfere in CAF-mediated drug resistance, aggressiveness, and metastatic behaviors of several cancer cell types. Due to the complex relevance of miRNA and CAFs, these non-coding oligonucleotides may serve as attractive scope for anti-cancer targeted therapies, but the lack of an efficient delivery system is still a major hurdle. Here, we have summarized the investigated information on CAF features, isolation, and induction procedures, and highlighted the miRNA-CAF communications, providing special insight into nano-delivery systems.

Dysregulated microRNAs in prostate cancer: In silico prediction and in vitro validation

Objectives

MicroRNAs, which are micro-coordinators of gene expression, have been recently investigated as a potential treatment for cancer. The study used computational techniques to identify microRNAs that could target a set of genes simultaneously. Due to their multi-target-directed nature, microRNAs have the potential to impact multiple key pathways and their pathogenic cross-talk.

Materials and Methods

We identified microRNAs that target a prostate cancer-associated gene set using integrated bioinformatics analyses and experimental validation. The candidate gene set included genes targeted by clinically approved prostate cancer medications. We used STRING, GO, and KEGG web tools to confirm gene-gene interactions and their clinical significance. Then, we employed integrated predicted and validated bioinformatics approaches to retrieve hsa-miR-124-3p, 16-5p, and 27a-3p as the top three relevant microRNAs. KEGG and DIANA-miRPath showed the related pathways for the candidate genes and microRNAs.

Results

The Real-time PCR results showed that miR-16-5p simultaneously down-regulated all genes significantly except for PIK3CA/CB in LNCaP; miR-27a-3p simultaneously down-regulated all genes significantly, excluding MET in LNCaP and PIK3CA in PC-3; and miR-124-3p could not down-regulate significantly PIK3CB, MET, and FGFR4 in LNCaP and FGFR4 in PC-3. Finally, we used a cell cycle assay to show significant G0/G1 arrest by transfecting miR-124-3p in LNCaP and miR-16-5p in both cell lines.

Conclusion

Our findings suggest that this novel approach may have therapeutic benefits and these predicted microRNAs could effectively target the candidate genes.

Advances in Genetic Reprogramming: Prospects from Developmental Biology to Regenerative Medicine

The foundations of cell reprogramming were laid by Yamanaka and co-workers, who showed that somatic cells can be reprogrammed into pluripotent cells (induced pluripotency). Since this discovery, the field of regenerative medicine has seen advancements. For example, because they can differentiate into multiple cell types, pluripotent stem cells are considered vital components in regenerative medicine aimed at the functional restoration of damaged tissue. Despite years of research, both replacement and restoration of failed organs/ tissues have remained elusive scientific feats. However, with the inception of cell engineering and nuclear reprogramming, useful solutions have been identified to counter the need for compatible and sustainable organs. By combining the science underlying genetic engineering and nuclear reprogramming with regenerative medicine, scientists have engineered cells to make gene and stem cell therapies applicable and effective. These approaches have enabled the targeting of various pathways to reprogramme cells, i.e., make them behave in beneficial ways in a patient-specific manner. Technological advancements have clearly supported the concept and realization of regenerative medicine. Genetic engineering is used for tissue engineering and nuclear reprogramming and has led to advances in regenerative medicine. Targeted therapies and replacement of traumatized , damaged, or aged organs can be realized through genetic engineering. Furthermore, the success of these therapies has been validated through thousands of clinical trials. Scientists are currently evaluating induced tissue-specific stem cells (iTSCs), which may lead to tumour-free applications of pluripotency induction. In this review, we present state-of-the-art genetic engineering that has been used in regenerative medicine. We also focus on ways that genetic engineering and nuclear reprogramming have transformed regenerative medicine and have become unique therapeutic niches.

Dual impacts of mesenchymal stem cell-derived exosomes on cancer cells: unravelling complex interactions

Mesenchymal stem cells (MSCs) are multipotent, self-renewing stromal cells found in a variety of adult tissues. MSCs possess a remarkable ability to migrate towards tumor sites, known as homing. This homing process is mediated by various factors, including chemokines, growth factors, and extracellular matrix components present in the tumor microenvironment. MSCs release extracellular vesicles known as exosomes (MSC-Exos), which have been suggested to serve a key role in mediating a wide variety of MSC activities. Through cell-cell communication, MSC-Exos have been shown to alter recipient cell phenotype or function and play as a novel cell-free alternative for MSC-based cell therapy. However, MSC recruitment to tumors allows for their interaction with cancer cells and subsequent regulation of tumor behavior. MSC-Exos act as tumor niche modulators via transferring exosomal contents, such as specific proteins or genetic materials, to the nearby cancer cells, leading to either promotion or suppression of tumorigenesis, angiogenesis, and metastasis, depending on the specific microenvironmental cues and recipient cell characteristics. Consequently, there is still a debate about the precise relationship between tumor cells and MSC-Exos, and it is unclear how MSC-Exos impacts tumor cells. Although the dysregulation of miRNAs is caused by the progression of cancer, they also play a direct role in either promoting or inhibiting tumor growth as they act as either oncogenes or tumor suppressors. The utilization of MSC-Exos may prove to be an effective method for restoring miRNA as a means of treating cancer. This review aimed to present the existing understanding of the impact that MSC-Exos could have on cancer. To begin with, we presented a brief explanation of exosomes, MSCs, and MSC-Exos. Following this, we delved into the impact of MSC-Exos on cancer growth, EMT, metastasis, angiogenesis, resistance to chemotherapy and radiotherapy, and modulation of the immune system. Opposing effects of mesenchymal stem cells-derived exosomes on cancer cells.

Current progress in engineered and nano-engineered mesenchymal stem cells for cancer: From mechanisms to therapy

Mesenchymal stem cells (MSCs), as self-renewing multipotent stromal cells, have been considered promising agents for cancer treatment. A large number of studies have demonstrated the valuable properties of MSC-based treatment, such as low immunogenicity and intrinsic tumor-trophic migratory properties. To enhance the potency of MSCs for therapeutic purposes, equipping MSCs with targeted delivery functions using genetic engineering is highly beneficial. Genetically engineered MSCs can express tumor suppressor agents such as pro-apoptotic, anti-proliferative, anti-angiogenic factors and act as ideal delivery vehicles. MSCs can also be loaded with nanoparticle drugs for increased efficacy and externally moderated targeting. Moreover, exosomes secreted by MSCs have important physiological properties, so they can contribute to intercellular communication and transfer cargo into targeted tumor cells. The precise role of genetically modified MSCs in tumor environments is still up for debate, but the beginning of clinical trials has been confirmed by promising results from preclinical investigations of MSC-based gene therapy for a wide range of malignancies. This review highlights the advanced techniques of engineering/nano-engineering and MSC-derived exosomes in tumor-targeted therapy.

Exosomes derived miR-362 exacerbates pneumonia by increasing Interleukin-6 via targeting VENTX

Pneumonia is a condition characterized by lung damage resulting from a robust immune response by the host. While the defense and immunity against bacterial lung infections have been extensively studied, little is known about the specific immune factors involved in the progression of bacterial pneumonia. To address this knowledge gap, our study aimed to compare normal lung tissues with pneumonia tissues using various techniques, including HE staining, RNA sequencing, RT-PCR, and Elisa assay. Our analysis revealed a significant increase in the levels of interleukin-6 (IL-6) in pneumonia tissues compared to normal lung tissues. To further investigate the underlying mechanism, we extracted exosomes from both pneumonia and normal lung tissues using ultracentrifugation. The exosomes were then examined using electron microscopy, diameter analysis, and western blot assay. RNA sequencing of the exosomes revealed an upregulation of several microRNAs (miRNAs), with miR-362 exhibiting the most significant change. This finding was confirmed through RT-PCR analysis conducted on lung tissues and alveolar lavage fluid. To gain insights into the specific target genes of miR-362, we employed bioinformatics analysis, which identified VENTX as a potential target gene. This finding was further validated through RT-PCR, western blot, and luciferase assay. Our experimental evidence demonstrated that miR-362 regulates VENTX expression, as evidenced by the use of miR-362 mimics or inhibitors on lung cells. Furthermore, we discovered that exosomes derived from pneumonia tissues upregulate IL-6 production through the miR-362/VENTX axis. Importantly, the blocking of IL-6 generation, which is facilitated by miR-362 inhibitor and VENTX overexpression lentivirus, can be achieved by treating exosomes. Moreover, we conducted in vivo experiments using pneumonia models. Rats were treated with IL-6, miR-362 mimics, or VENTX knock-down lentivirus. The results demonstrated a worse prognosis for rats treated with these factors, indicating their potential as prognostic markers. Taken together, our study suggests that exosomes facilitate IL-6 generation by transferring miR-362, thereby suppressing VENTX transcription. Consequently, the IL-6/miR-362/VENTX axis emerges as a promising therapeutic target for pneumonia.

Mesenchymal stem cells, as glioma exosomal immunosuppressive signal multipliers, enhance MDSCs immunosuppressive activity through the miR-21/SP1/DNMT1 positive feedback loop

BACKGROUND

The immunosuppressive microenvironment in glioma induces immunotherapy resistance and is associated with poor prognosis. Glioma-associated mesenchymal stem cells (GA-MSCs) play an important role in the formation of the immunosuppressive microenvironment, but the mechanism is still not clear.

RESULTS

We found that GA-MSCs promoted the expression of CD73, an ectonucleotidase that drives immunosuppressive microenvironment maintenance by generating adenosine, on myeloid-derived suppressor cells (MDSCs) through immunosuppressive exosomal miR-21 signaling. This process was similar to the immunosuppressive signaling mediated by glioma exosomal miR-21 but more intense. Further study showed that the miR-21/SP1/DNMT1 positive feedback loop in MSCs triggered by glioma exosomal CD44 upregulated MSC exosomal miR-21 expression, amplifying the glioma exosomal immunosuppressive signal. Modified dendritic cell-derived exosomes (Dex) carrying miR-21 inhibitors could target GA-MSCs and reduce CD73 expression on MDSCs, synergizing with anti-PD-1 monoclonal antibody (mAb).

CONCLUSIONS

Overall, this work reveals the critical role of MSCs in the glioma microenvironment as signal multipliers to enhance immunosuppressive signaling of glioma exosomes, and disrupting the positive feedback loop in MSCs with modified Dex could improve PD-1 blockade therapy.

MicroRNA (miR)-124: A Promising Therapeutic Gateway for Oncology

MicroRNA (miR) are a class of small non-coding RNA that are involved in post-transcriptional gene regulation. Altered expression of miR has been associated with several pathological conditions. MicroRNA-124 (miR-124) is an abundantly expressed miR in the brain as well as the thymus, lymph nodes, bone marrow, and peripheral blood mono-nuclear cells. It plays a key role in the regulation of the host immune system. Emerging studies show that dysregulated expression of miR-124 is a hallmark in several cancer types and it has been attributed to the progression of these malignancies. In this review, we present a comprehensive summary of the role of miR-124 as a promising therapeutic gateway in oncology.

miRNA-Guided Regulation of Mesenchymal Stem Cells Derived from the Umbilical Cord: Paving the Way for Stem-Cell Based Regeneration and Therapy

The human body is an abundant source of multipotent cells primed with unique properties that can be exploited in a multitude of applications and interventions. Mesenchymal stem cells (MSCs) represent a heterogenous population of undifferentiated cells programmed to self-renew and, depending on their origin, differentiate into distinct lineages. Alongside their proven ability to transmigrate toward inflammation sites, the secretion of various factors that participate in tissue regeneration and their immunoregulatory function render MSCs attractive candidates for use in the cytotherapy of a wide spectrum of diseases and conditions, as well as in different aspects of regenerative medicine. In particular, MSCs that can be found in fetal, perinatal, or neonatal tissues possess additional capabilities, including predominant proliferation potential, increased responsiveness to environmental stimuli, and hypoimmunogenicity. Since microRNA (miRNA)-guided gene regulation governs multiple cellular functions, miRNAs are increasingly being studied in the context of driving the differentiation process of MSCs. In the present review, we explore the mechanisms of miRNA-directed differentiation of MSCs, with a special focus on umbilical cord-derived mesenchymal stem cells (UCMSCs), and we identify the most relevant miRNAs and miRNA sets and signatures. Overall, we discuss the potent exploitations of miRNA-driven multi-lineage differentiation and regulation of UCMSCs in regenerative and therapeutic protocols against a range of diseases and/or injuries that will achieve a meaningful clinical impact through maximizing treatment success rates, while lacking severe adverse events.

Therapeutic and Diagnostic Potential of Exosomes as Drug Delivery Systems in Brain Cancer

Cancer is designated as one of the principal causes of mortality universally. Among different types of cancer, brain cancer remains the most challenging one due to its aggressiveness, the ineffective permeation ability of drugs through the blood-brain barrier (BBB), and drug resistance. To overcome the aforementioned issues in fighting brain cancer, there is an imperative need for designing novel therapeutic approaches. Exosomes have been proposed as prospective "Trojan horse" nanocarriers of anticancer theranostics owing to their biocompatibility, increased stability, permeability, negligible immunogenicity, prolonged circulation time, and high loading capacity. This review provides a comprehensive discussion on the biological properties, physicochemical characteristics, isolation methods, biogenesis and internalization of exosomes, while it emphasizes their therapeutic and diagnostic potential as drug vehicle systems in brain cancer, highlighting recent advances in the research field. A comparison of the biological activity and therapeutic effectiveness of several exosome-encapsulated cargo including drugs and biomacromolecules underlines their great supremacy over the non-exosomal encapsulated cargo in the delivery, accumulation, and biological potency. Various studies on cell lines and animals give prominence to exosome-based nanoparticles (NPs) as a promising and alternative approach in the management of brain cancer.

Recent Advancements on the Use of Exosomes as Drug Carriers for the Treatment of Glioblastoma

Glioblastoma (GBM) is the most common and aggressive cancer of the brain. Presently, GBM patients have a poor prognosis, and therapy primarily aims to extend the life expectancy of affected patients. The current treatment of GBM in adult cases and high-grade gliomas in the pediatric population involves a multimodal approach that includes surgical resection followed by simultaneous chemo/radiotherapy. Exosomes are nanoparticles that transport proteins and nucleic acids and play a crucial role in mediating intercellular communication. Recent evidence suggests that these microvesicles may be used as biological carriers and offer significant advantages in targeted therapy. Due to their inherent cell-targeting properties, circulation stability, and biocompatibility, exosomes are emerging as promising new carriers for drugs and biotherapeutics. Furthermore, these nanovesicles are a repository of potential diagnostic and prognostic markers. In this review, we focus on the therapeutic potentials of exosomes in nano-delivery and describe the latest evidence of their use as a therapeutic tool in GBM.

The Role of Mesenchymal Stem Cells and Exosomes in Tumor Development and Targeted Antitumor Therapies

Mesenchymal stem cells (MSCs) can be isolated from various tissues in adults and differentiated into cells of the osteoblasts, adipocytes, chondrocytes, and myocytes. Recruitments of MSCs towards tumors have a crucial contribution to tumor development. However, the role of MSCs in the tumor microenvironment is uncertain. In addition, due to its tropism to the tumor and low immunogenic properties, more and more pieces of evidence indicate that MSCs may be an ideal carrier for antitumor biologics such as cytokines, chemotherapeutic agents, and oncolytic viruses. Here, we review the existing knowledge on the anti- and protumorigenic effect of MSCs and their extracellular vesicles and exosomes, the role of MSCs, and their extracellular vesicles and exosomes as antitumor vectors.

Cold atmospheric plasma: Novel opportunities for tumor microenvironment targeting

With mounting preclinical and clinical evidences on the prominent roles of the tumor microenvironment (TME) played during carcinogenesis, the TME has been recognized and used as an important onco-therapeutic target during the past decade. Delineating our current knowledge on TME components and their functionalities can help us recognize novel onco-therapeutic opportunities and establish treatment modalities towards desirable anti-cancer outcome. By identifying and focusing on primary cellular components in the TME, that is, tumor-infiltrating lymphocytes, tumor-associated macrophages, cancer-associated fibroblasts and mesenchymal stem cells, we decomposed their primary functionalities during carcinogenesis, categorized current therapeutic approaches utilizing traits of these components, and forecasted possible benefits that cold atmospheric plasma, a redox modulating tool with selectivity against cancer cells, may convey by targeting the TME. Our insights may open a novel therapeutic avenue for cancer control taking advantages of redox homeostasis and immunostasis.

Mesenchymal stem cell therapy for neurological disorders: The light or the dark side of the force?

Neurological disorders are recognized as major causes of death and disability worldwide. Because of this, they represent one of the largest public health challenges. With awareness of the massive burden associated with these disorders, came the recognition that treatment options were disproportionately scarce and, oftentimes, ineffective. To address these problems, modern research is increasingly looking into novel, more effective methods to treat neurological patients; one of which is cell-based therapies. In this review, we present a critical analysis of the features, challenges, and prospects of one of the stem cell types that can be employed to treat numerous neurological disorders-mesenchymal stem cells (MSCs). Despite the fact that several studies have already established the safety of MSC-based treatment approaches, there are still some reservations within the field regarding their immunocompatibility, heterogeneity, stemness stability, and a range of adverse effects-one of which is their tumor-promoting ability. We additionally examine MSCs' mechanisms of action with respect to in vitro and in vivo research as well as detail the findings of past and ongoing clinical trials for Parkinson's and Alzheimer's disease, ischemic stroke, glioblastoma multiforme, and multiple sclerosis. Finally, this review discusses prospects for MSC-based therapeutics in the form of biomaterials, as well as the use of electromagnetic fields to enhance MSCs' proliferation and differentiation into neuronal cells.

Extracellular vesicles: emerging anti-cancer drugs and advanced functionalization platforms for cancer therapy

Increasing evidences show that unmodified extracellular vesicles (EVs) derived from various cells can effectively inhibit the malignant progression of different types of tumors by delivering the bioactive molecules. Therefore, EVs are expected to be developed as emerging anticancer drugs. Meanwhile, unmodified EVs as an advanced and promising nanocarrier that is frequently used in targeted delivery therapeutic cargos and personalized reagents for the treatment and diagnosis of cancer. To improve the efficacy of EV-based treatments, researchers are trying to engineering EVs as an emerging nanomedicine translational therapy platform through biological, physical and chemical approaches, which can be broaden and altered to enhance their therapeutic capability. EVs loaded with therapeutic components such as tumor suppressor drugs, siRNAs, proteins, peptides, and conjugates exhibit significantly enhanced anti-tumor effects. Moreover, the design and preparation of tumor-targeted modified EVs greatly enhance the specificity and effectiveness of tumor therapy, and these strategies are expected to become novel ideas for tumor precision medicine. This review will focus on reviewing the latest research progress of functionalized EVs, clarifying the superior biological functions and powerful therapeutic potential of EVs, for researchers to explore new design concepts based on EVs and build next-generation nanomedicine therapeutic platforms.

Mesenchymal stem cell-derived exosomes as a new therapeutic strategy in the brain tumors

Brain tumors are one of the most mortal cancers, leading to many deaths among kids and adults. Surgery, chemotherapy, and radiotherapy are available options for brain tumor treatment. However, these methods are not able to eradicate cancer cells. The blood-brain barrier (BBB) is one of the most important barriers to treat brain tumors that prevents adequate drug delivery to brain tissue. The connection between different brain parts is heterogeneous and causes many challenges in treatment. Mesenchymal stem cells (MSCs) migrate to brain tumor cells and have anti-tumor effects by delivering cytotoxic compounds. They contain very high regenerative properties, as well as support the immune system. MSCs-based therapy involves cell replacement and releases various vesicles, including exosomes. Exosomes receive more attention due to their excellent stability, less immunogenicity and toxicity compare to cells. Exosomes derived from MSCs can develop a powerful therapeutic strategy for different diseases and be a hopeful candidate for cell-based and cell-free regenerative medicine. These nanoparticles contain nucleic acid, proteins, lipids, microRNAs, and other biologically active substances. Many studies show that each microRNA can prevent angiogenesis, migration, and metastasis in glioblastoma. These exosomes can-act as a suitable nanoparticle carrier for therapeutic applications of brain tumors by passing through the BBB. In this review, we discuss potential applications of MSC and their produced exosomes in the treatment of brain tumors.

Exosomes Secreted from Mesenchymal Stem Cells Carry miR-486-5p to Inhibit Cell Proliferation and the Epithelial-Mesenchymal Transition Process to Treat Human Lung Cancer by Down-Regulating MIER3

Exosomes are nano-vesicles that can shuttle active cargoes. Mesenchymal stem cells play a complex function in tumour progression.We investigated the effect of miR-486-5p, an exosome of human bone marrow-derived MSCs on lung cancer. We found that miR-486-5p, carried in mesenchymal stem cells and mesenchymal stem cell-derived exosomes, regulates MIER3 expression by binding to its 3’UTR, thereby inhibiting the epithelial-mesenchymal transition process of A549 cells. In vivo, we demonstrated that exosome treatment reduced the area of tumour necrosis, increased the expression of miR-486-5p and inhibited the epithelial–mesenchymal transition process in mice. In conclusion, mesenchymal stem cell-derived exosomal miR-486-5p directly and negatively targets MIER3 to inhibit lung cancer.

Mouse Bone Marrow Mesenchymal Stem Cells Inhibit Sepsis-Induced Lung Injury in Mice via Exosomal SAA1

Sepsis is a global disease burden, and approximately 40% of cases develop acute lung injury (ALI). Bone marrow mesenchymal stromal cells (BMSCs) and their exosomes are widely used in treating a variety of diseases including sepsis. As an acute phase protein, serum amyloid A1 (SAA1) regulates inflammation and immunity. However, the role of SAA1 in BMSCs-exosomes in septic lung injury remains to be elucidated. Exosomes derived from serum and BMSCs were isolated by ultracentrifugation. SAA1 was silenced or overexpressed in mouse BMSCs using lentiviral plasmids, containing either SAA1-targeting short interfering RNAs or SAA1 cDNA. Sepsis was induced by cecal ligation and puncture (CLP). LPS was used to induce ALI in mice. Mouse alveolar macrophages were isolated by flow cytometry. Levels of SAA1, endotoxin, TNF-α, and IL-6 were measured using commercial kits. LPS internalization was monitored by immunostaining. RT-qPCR or immunoblots were performed to test gene and protein expressions. Serum exosomes of patients with sepsis-induced lung injury had significantly higher levels of SAA1, endotoxin, TNF-α, and IL-6. Overexpression of SAA1 in BMSCs inhibited CLP- or LPS-induced lung injury and decreased CLP- or LPS-induced endotoxin, TNF-α, and IL-6 levels. Administration of the SAA1 blocking peptide was found to partially inhibit SAA1-induced LPS internalization by mouse alveolar macrophages and reverse the protective effect of SAA1. In conclusion, BMSCs inhibit sepsis-induced lung injury through exosomal SAA1. These results highlight the importance of BMSCs, exosomes, and SAA1, which may provide novel directions for the treatment of septic lung injury.

Integrated Analysis of Multiomics Data Identified Molecular Subtypes and Oxidative Stress-Related Prognostic Biomarkers in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a glioma in IV stage, which is one of the most common primary malignant brain tumors in adults. GBM has the characters of high invasiveness, high recurrence rate, and low survival rate and with a poor prognosis. GBM implicates various genetic changes and epigenetic and gene transcription disorders, which are crucial in developing GBM. With the progression and enhancement of high-throughput sequencing technologies, the acquirement and administering approaches of diverse biological omics data on distinctive levels are developing more advanced. However, the research of GBM with multiomics remains largely unknown. We identified GBM-related molecular subtypes by integrated multiomics data and exploring the connections of gene copy number variation (CNV) and methylation gene (MET) change data. The expression of CNV and MET genes was examined through cluster integration analysis. The present study confirmed three clusters (iC1, iC2, and iC3) with distinctive prognosis and molecule peculiarities. We also recognized three oxidative stress protecting molecules (OSMR, IGFBP6, and MYBPH) by contrasting gene expression, MET, and CNV in the three subtypes. OSMR, IGFBP6, and MYBPH were differentially expressed in the clusters, suggesting they might be recognized as characteristic markers for the three clusters in GBM. Through integrative investigation of genomics, epigenomics, and transcriptomics, we offer novel visions into the multilayered molecules of GBM and facilitate the accuracy remedy for GBM sufferers.

Extracellular vesicles and particles impact the systemic landscape of cancer

Intercellular cross talk between cancer cells and stromal and immune cells is essential for tumor progression and metastasis. Extracellular vesicles and particles (EVPs) are a heterogeneous class of secreted messengers that carry bioactive molecules and that have been shown to be crucial for this cell-cell communication. Here, we highlight the multifaceted roles of EVPs in cancer. Functionally, transfer of EVP cargo between cells influences tumor cell growth and invasion, alters immune cell composition and function, and contributes to stromal cell activation. These EVP-mediated changes impact local tumor progression, foster cultivation of pre-metastatic niches at distant organ-specific sites, and mediate systemic effects of cancer. Furthermore, we discuss how exploiting the highly selective enrichment of molecules within EVPs has profound implications for advancing diagnostic and prognostic biomarker development and for improving therapy delivery in cancer patients. Altogether, these investigations into the role of EVPs in cancer have led to discoveries that hold great promise for improving cancer patient care and outcome.

Exosomes to control glioblastoma multiforme: Investigating the effects of mesenchymal stem cell-derived exosomes on C6 cells in vitro

Glioblastoma multiforme (GBM) is a common, aggressive, fast-growing tumor of the central nervous system that currently has no effective treatment. Although stem cell therapy has shown promising in vitro achievements, the blood-brain barrier (BBB) has always been a major hurdle to clinical success. To overcome this challenge, exosomes have been targeted as attractive drug delivery agents in numerous studies since they are small enough to enter the BBB. Furthermore, exosomes' characteristics and compositions are directly determined by the parent cell and these heritable traits affect their cell interactions. This article focuses on exosomes as an alternative to stem cell therapy to regulate glioma cell activity. Exosomes were isolated from rat bone marrow mesenchymal stem cells (rBMMSCs) by ultracentrifugation method and then characterized via western blot, dynamic light scattering, scanning, and transmission electron microscopy. Next, various concentrations of the exosomes were incubated with C6 cells and their effects at different time points were evaluated in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Annexin/Pi assay results confirmed that the isolated exosomes cause cell death mostly through apoptosis, and a linear correlation was observed between exosomes' concentration and their cytotoxicity. Following that, the scratch test, colony formation test, and Transwell assay confirmed exosomes' significant impact on the migration and invasion behavior of C6 cells. For the first time, rBMMSC-derived exosomes have been used as a single treatment for GBM rather than in combination with other treatments or as a pharmaceutical carrier.

MicroRNAs as prognostic markers and therapeutic targets in gliomas

Gliomas are invasive brain tumors characterized by high rates of recurrence and mortality. Glioblastoma (GBM), a grade IV brain tumor, is known for its heterogenicity and its resistance to the current treatment regimen. MicroRNA (miRNAs) are small non-coding sequences of RNA that regulate and influence the expression of multiple genes. The detection of certain types of micro-RNA in tissues and blood serum can be used for diagnosis and prognosis, including the response of a particular patient to therapy. The purpose of this review is to analyze studies and experimental results concerning changes in microRNA expression profiles characteristic of gliomas. Furthermore, miRNAs also contribute to autophagy at multiple stages. In this review, we summarize the functions of miRNAs in GBM pathways linked to dysregulation of cell cycle control, apoptosis and resistance to treatment, and the possible use of miRNAs in clinical settings as treatment and prediction biomarkers.

MicroRNA delivery systems in glioma therapy and perspectives: A systematic review

Gliomas are the deadliest of all primary brain tumors, and they constitute a serious global health problem. MicroRNAs (miRNAs) are gene expression regulators associated with glioma pathogenesis. Thus, miRNAs represent potential therapeutic agents for treating gliomas. However, miRNAs have not been established as part of the regular clinical armamentarium. This systemic review evaluates current molecular and pre-clinical studies with the aim of defining the most appealing supramolecular platform for administering therapeutic miRNA to patients with gliomas. An integrated analysis suggested that cationic lipid nanoparticles, functionalized with octa-arginine peptides, represent a potentially specific, practical, non-invasive intervention for treating gliomas. This supramolecular platform allows loading both hydrophilic (miRNA) and hydrophobic (anti-tumor drugs, like temozolomide) molecules. This systemic review is the first to describe miRNA delivery systems targeted to gliomas that integrate several types of molecules as active ingredients. Further experimental validation is warranted to confirm the practical value of miRNA delivery systems.

Heterogeneity of In Vitro Expanded Mesenchymal Stromal Cells and Strategies to Improve Their Therapeutic Actions

Beneficial properties of mesenchymal stromal cells (MSCs) have prompted their use in preclinical and clinical research. Accumulating evidence has been provided for the therapeutic effects of MSCs in several pathologies, including neurodegenerative diseases, myocardial infarction, skin problems, liver disorders and cancer, among others. Although MSCs are found in multiple tissues, the number of MSCs is low, making in vitro expansion a required step before MSC application. However, culture-expanded MSCs exhibit notable differences in terms of cell morphology, physiology and function, which decisively contribute to MSC heterogeneity. The changes induced in MSCs during in vitro expansion may account for the variability in the results obtained in different MSC-based therapy studies, including those using MSCs as living drug delivery systems. This review dissects the different changes that occur in culture-expanded MSCs and how these modifications alter their therapeutic properties after transplantation. Furthermore, we discuss the current strategies developed to improve the beneficial effects of MSCs for successful clinical implementation, as well as potential therapeutic alternatives.

Therapeutically harnessing extracellular vesicles

The field of extracellular vesicle (EV) research has developed rapidly over the last decade from the study of fundamental biology to a subject of significant clinical relevance. The potential of harnessing EVs in the diagnosis and treatment of diseases - including cancer and neurological and cardiovascular disorders - is now being recognized. Accordingly, the applications of EVs as therapeutic targets, biomarkers, novel drug delivery agents and standalone therapeutics are being actively explored. This Review provides a brief overview of the characteristics and physiological functions of the various classes of EV, focusing on their association with disease and emerging strategies for their therapeutic exploitation.

Mesenchymal stem cell (MSC)-derived exosomes as novel vehicles for delivery of miRNAs in cancer therapy

Mesenchymal stem cells (MSCs) are known as promising sources for cancer therapy and can be utilized as vehicles in cancer gene therapy. MSC-derived exosomes are central mediators in the therapeutic functions of MSCs, known as the novel cell-free alternatives to MSC-based cell therapy. MSC-derived exosomes show advantages including higher safety as well as more stability and convenience for storage, transport and administration compared to MSCs transplant therapy. Unmodified MSC-derived exosomes can promote or inhibit tumors while modified MSC-derived exosomes are involved in the suppression of cancer development and progression via the delivery of several therapeutics molecules including chemotherapeutic drugs, miRNAs, anti-miRNAs, specific siRNAs, and suicide gene mRNAs. In most malignancies, dysregulation of miRNAs not only occurs as a consequence of cancer progression but also is directly involved during tumor initiation and development due to their roles as oncogenes (oncomiRs) or tumor suppressors (TS-miRNAs). MiRNA restoration is usually achieved by overexpression of TS-miRNAs using synthetic miRNA mimics and viral vectors or even downregulation of oncomiRs using anti-miRNAs. Similar to other therapeutic molecules, the efficacy of miRNAs restoration in cancer therapy depends on the effectiveness of the delivery system. In the present review, we first provided an overview of the properties and potentials of MSCs in cancer therapy as well as the application of MSC-derived exosomes in cancer therapy. Finally, we specifically focused on harnessing the MSC-derived exosomes for the aim of miRNA delivery in cancer therapy.

Nature-inspired dynamic gene-loaded nanoassemblies for the treatment of brain diseases

Gene therapy has great potential to treat brain diseases. However, genetic drugs need to overcome a cascade of barriers for their full potential. The conventional delivery systems often struggle to meet expectations. Natural biological particles that are highly optimized for specific functions in body, can inspire optimization of dynamic gene-loaded nanoassemblies (DGN). The DGN refer to gene loaded nanoassemblies whose functions and structures are changeable in response to the biological microenvironments or can dynamically interact with tissues or cells. The nature-inspired DGN can meet the needs in brain diseases treatment, including i) Non-elimination in blood (N), ii) Across the blood-brain barrier (A), iii) Targeting cells (T), iv) Efficient uptake (U), v) Controllable release (R), vi) Eyeable (E)-abbreviated as the "NATURE". In this Review, from nature to "NATURE", we mainly summarize the specific application of nature-inspired DGN in the "NATURE" cascade process. Furthermore, the Review provides an outlook for this field.

Extracellular Vesicles, Stem Cells and the Role of miRNAs in Neurodegeneration

There are different modalities of intercellular communication governed by cellular homeostasis. In this review, we will explore one of these forms of communication called extracellular vesicles (EVs). These vesicles are released by all cells in the body and are heterogeneous in nature. The primary function of EVs is to share information through their cargo consisting of proteins, lipids and nucleic acids (mRNA, miRNA, dsDNA etc.) with other cells, which have a direct consequence on their microenvironment. We will focus on the role of EVs of mesenchymal stem cells (MSCs) in the nervous system and how these participate in intercellular communication to maintain physiological function and provide neuroprotection. However, deregulation of this same communication system could play a role in several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, multiple sclerosis, prion disease and Huntington's disease. The release of EVs from a cell provides crucial information to what is happening inside the cell and thus could be used in diagnostics and therapy. We will discuss and explore new avenues for the clinical applications of using engineered MSC-EVs and their potential therapeutic benefit in treating neurodegenerative diseases.

Modulating microRNAs in cancer: Next-generation therapies

MicroRNAs (miRNAs) are a class of endogenously expressed non-coding regulators of the genome with an ability to mediate a variety of biological and pathological processes. There is growing evidence demonstrating frequent dysregulation of microRNAs in cancer cells, which is associated with tumor initiation, development, migration, invasion, resisting cell death, and drug resistance. Studies have shown that modulation of these small RNAs is a novel and promising therapeutic tool in the treatment of a variety of diseases, especially cancer, due to their broad influence on multiple cellular processes. However, suboptimal delivery of the appropriate miRNA to the cancer sites, quick degradation by nucleases in the blood circulation, and off target effects have limited their research and clinical applications. Therefore, there is a pressing need to improve the therapeutic efficacy of miRNA modulators, while at the same time reducing their toxicities. Several delivery vehicles for miRNA modulators have been shown to be effective in vitro and in vivo. In this review, we will discuss the role and importance of miRNAs in cancer and provide perspectives on currently available carriers for miRNA modulation. We will also summarize the challenges and prospects for the clinical translation of miRNA-based therapeutic strategies.

Application of Mesenchymal Stem Cells in Targeted Delivery to the Brain: Potential and Challenges of the Extracellular Vesicle-Based Approach for Brain Tumor Treatment

Treating brain tumors presents enormous challenges, and there are still poor prognoses in both adults and children. Application of novel targets and potential drugs is hindered by the function of the blood-brain barrier, which significantly restricts therapeutic access to the tumor. Mesenchymal stem cells (MSCs) can cross biological barriers, migrate to sites of injuries to exert many healing effects, and be engineered to incorporate different types of cargo, making them an ideal vehicle to transport anti-tumor agents to the central nervous system. Extracellular vesicles (EVs) produced by MSCs (MSC-EVs) have valuable innate properties from parent cells, and are being exploited as cell-free treatments for many neurological diseases. Compared to using MSCs, targeted delivery via MSC-EVs has a better pharmacokinetic profile, yet avoids many critical issues of cell-based systems. As the field of MSC therapeutic applications is quickly expanding, this article aims to give an overall picture for one direction of EV-based targeting of brain tumors, with updates on available techniques, outcomes of experimental models, and critical challenges of this concept.

Mesenchymal stem cells in cancer therapy; the art of harnessing a foe to a friend

For a long time, mesenchymal stem cells (MSCs) were discussed only as stem cells which could give rise to different types of cells. However, when it became clear that their presence in the tumor microenvironment (TME) was like a green light for tumorigenesis, they emerged from the ashes. This review was arranged to provide a comprehensive and precise description of MSCs' role in regulating tumorigenesis and to discuss the dark and the bright sides of cancer treatment strategies using MSCs. To gather the details about MSCs, we made an intensive literature review using keywords, including MSCs, tumor microenvironment, tumorigenesis, and targeted therapy. Through transferring cytokines, growth factors, and microRNAs, MSCs maintain the cancer stem cell population, increase angiogenesis, provide a facility for cancer metastasis, and shut down the anti-tumor activity of the immune system. Although MSCs progress tumorigenesis, there is a consensus that these cells could be used as a vehicle to transfer anti-cancer agents into the tumor milieu. This feature opened a new chapter in MSCs biology, this time from the therapeutic perspective. Although the data are not sufficient, the advent of new genetic engineering methods might make it possible to engage these cells as Trojan horses to eliminate the malignant population. So many years of investigation showed that MSCs are an important group of cells, residing in the TME, studying the function of which not only could add a delicate series of information to the process of tumorigenesis but also could revolutionize cancer treatment strategies.

Targeting Non-coding RNA for Glioblastoma Therapy: The Challenge of Overcomes the Blood-Brain Barrier

Glioblastoma (GBM) is the most malignant form of all primary brain tumors, and it is responsible for around 200,000 deaths each year worldwide. The standard therapy for GBM treatment includes surgical resection followed by temozolomide-based chemotherapy and/or radiotherapy. With this treatment, the median survival rate of GBM patients is only 15 months after its initial diagnosis. Therefore, novel and better treatment modalities for GBM treatment are urgently needed. Mounting evidence indicates that non-coding RNAs (ncRNAs) have critical roles as regulators of gene expression. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are among the most studied ncRNAs in health and disease. Dysregulation of ncRNAs is observed in virtually all tumor types, including GBMs. Several dysregulated miRNAs and lncRNAs have been identified in GBM cell lines and GBM tumor samples. Some of them have been proposed as diagnostic and prognostic markers, and as targets for GBM treatment. Most ncRNA-based therapies use oligonucleotide RNA molecules which are normally of short life in circulation. Nanoparticles (NPs) have been designed to increase the half-life of oligonucleotide RNAs. An additional challenge faced not only by RNA oligonucleotides but for therapies designed for brain-related conditions, is the presence of the blood-brain barrier (BBB). The BBB is the anatomical barrier that protects the brain from undesirable agents. Although some NPs have been derivatized at their surface to cross the BBB, optimal NPs to deliver oligonucleotide RNA into GBM cells in the brain are currently unavailable. In this review, we describe first the current treatments for GBM therapy. Next, we discuss the most relevant miRNAs and lncRNAs suggested as targets for GBM therapy. Then, we compare the current drug delivery systems (nanocarriers/NPs) for RNA oligonucleotide delivery, the challenges faced to send drugs through the BBB, and the strategies to overcome this barrier. Finally, we categorize the critical points where research should be the focus in order to design optimal NPs for drug delivery into the brain; and thus move the Oligonucleotide RNA-based therapies from the bench to the clinical setting.

Mesenchymal stem/stromal cells as next-generation drug delivery vehicles for cancer therapeutics

INTRODUCTION

Drug delivery to solid tumors remains a significant therapeutic challenge. Mesenchymal stem/stromal cells (MSCs) home to tumor tissues and can be employed as tumor targeted drug/gene delivery vehicles. Reportedly, therapeutic gene- or anti-cancer drug-loaded MSCs have shown remarkable anti-tumor effects in preclinical studies, and some clinical trials for assessing therapeutic MSCs in patients with cancer have been registered.

AREAS COVERED

In the present review, we first discuss the source and interdonor heterogeneity of MSCs, their tumor-homing mechanism, and the route of MSC administration in MSC-based cancer therapy. We then summarize the therapeutic applications of MSCs as a drug delivery vehicle for therapeutic genes or anti-cancer drugs and the drug delivery mechanism from drug-loaded MSCs to cancer cells.

EXPERT OPINION

Although numerous preclinical studies have revealed significant anti-tumor effects, several clinical trials assessing MSC-based cancer gene therapy have failed to demonstrate corroborative results, documenting limited therapeutic effects. Notably, a successful clinical outcome with MSC-based cancer therapy would require the interdonor heterogeneity of administered MSCs to be resolved, along with improved tumor-homing efficiency and optimized drug delivery efficiency from MSCs to cancer cells.

The Multifaceted Role of Extracellular Vesicles in Glioblastoma: microRNA Nanocarriers for Disease Progression and Gene Therapy

Glioblastoma (GB) is the most aggressive form of brain cancer in adults, characterized by poor survival rates and lack of effective therapies. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression post-transcriptionally through specific pairing with target messenger RNAs (mRNAs). Extracellular vesicles (EVs), a heterogeneous group of cell-derived vesicles, transport miRNAs, mRNAs and intracellular proteins, and have been shown to promote horizontal malignancy into adjacent tissue, as well as resistance to conventional therapies. Furthermore, GB-derived EVs have distinct miRNA contents and are able to penetrate the blood-brain barrier. Numerous studies have attempted to identify EV-associated miRNA biomarkers in serum/plasma and cerebrospinal fluid, but their collective findings fail to identify reliable biomarkers that can be applied in clinical settings. However, EVs carrying specific miRNAs or miRNA inhibitors have great potential as therapeutic nanotools in GB, and several studies have investigated this possibility on in vitro and in vivo models. In this review, we discuss the role of EVs and their miRNA content in GB progression and resistance to therapy, with emphasis on their potential as diagnostic, prognostic and disease monitoring biomarkers and as nanocarriers for gene therapy.

Mesenchymal stem cells in glioblastoma therapy and progression: How one cell does it all

Mesenchymal stem cells (MSCs) are among the most investigated and applied somatic stem cells in experimental therapies for the regeneration of damaged tissues. Moreover, as it was recently postulated, MSCs may demonstrate anti-tumor properties. Glioblastoma (GBM) is a grade IV central nervous system tumor with no available effective therapy and an inevitably fatal prognosis. Experimental studies utilizing MSCs in GBM treatment resulted in numerous controversies. Native MSCs were shown to exert anti-GBM activity by controlling angiogenesis, regulating cell cycle, and inducing apoptosis. They also were used as sensitizing factors and vehicles delivering various anti-cancer compounds. On the other hand, some experiments revealed significant risks related to MSC-based therapies for GBM, such as enhancement of tumor cell proliferation, invasion, and aggressiveness. The following review elaborates on all mentioned contradictory data and provides a realistic, current clinical perspective on MSCs' potential in GBM treatment.

Targeting CD146 using folic acid-conjugated nanoparticles and suppression of tumor growth in a mouse glioma model

OBJECTIVE

Glioma stem cells (GSCs) are responsible for tumor initiation, therapeutic resistance, and recurrence. CD146 is mainly expressed in dividing GSCs and regulates cell cycle progression. However, the evaluation of the efficacy of targeted therapy against CD146 in vivo remains to be investigated. In this study, the authors aimed to develop gene therapy targeting GSCs using chitosan oligosaccharide lactate (COL) nanoparticles (NPs) conjugated with folic acid-polyethylene glycol (FA-PEG-COL NPs) for in vitro and in vivo delivery of CD146 small-interfering RNA (siCD146) and to determine the effect of CD146 knockdown on tumor growth.

METHODS

To examine the uptake of NPs by tumor cells, immunofluorescence staining, flow cytometry, and in vivo imaging were performed. The knockdown effect of siCD146 was measured by western blot and water-soluble tetrazolium salt-8 assay in mouse glioma cells. The efficacy of siRNA therapy-targeted GSCs was evaluated by monitoring tumor growth through in vivo imaging and histological analysis.

RESULTS

In vivo accumulation of the FA-PEG-COL NPs in subcutaneous and intracranial gliomas following NP administration via a mouse tail vein was observed. Additionally, in vitro delivery of siCD146 ionically cross-linked NPs, reduced CD146 levels, and suppressed growth in the glioma tumor sphere. Evaluation of the in vivo therapeutic effects of siCD146-cross-linked NPs in a mouse glioma model revealed significant suppression of intracranial tumor growth, with complete removal of the tumor observed in some mice on histological examination. Furthermore, delivery of siCD146 significantly reduced the Ki-67 index in residual tumor tissues relative to that in control mice.

CONCLUSIONS

CD146 is a potential therapeutic target, and folic acid-conjugated NPs delivering siRNA may facilitate gene therapy in malignant gliomas.

MicroRNA-30c delivered by bone marrow-mesenchymal stem cells induced apoptosis and diminished cell invasion in U-251 glioblastoma cell line

BACKGROUND

Glioblastoma multiform (GBM) is the most belligerent and prevalent brain malignancy among adults. Due to the blood-brain barrier (BBB), drug administration is confronted by massive challenges, making resectional surgery the only treatment pipeline. MicroRNAs have recently absorbed the attention of studies for correlating with the progression of various malignancies. miR-30c has been reported to play a role in cell proliferation, metabolism, and apoptosis process. For instance, miR-30c has been reported to regulate apoptosis through the TNF-related apoptosis-inducing ligand (TRAIL). miR-30c also targets IL-6, which further induces apoptosis. Besides, miR-30c inhibits glioma proliferation and its migratory ability. Besides, the overexpression of miR-30c arrested cells at G0 as well as dampening their migration and invasion. However, it has been shown that the expression level of miR-30c was low in glioma. MSCs can migrate toward tumor cells which is called tumor-tropism, in which they are capable of delivering engineered miR-30c based on gap junction and non-intimacy mechanisms.

MATERIAL AND METHODS

MiR-30c was cloned into pCDH-CMV-MCS-EF1-copGFP vector utilizing XbaI and EcoRI in order to construct pCDH-miR-30c. Then psPAX2, pMD2.G, and pCDH-miR-30c were co-transfected into Hek-293T to yield lenti-miR-30c virus particles. Next, bone marrow-mesenchymal stem cells (BM-MSCs) were Transduced with lenti-miR-30c. Thereafter, we co-cultured U-251 cell line with BM-MCSs-miR-30c and evaluated the apoptosis rate and the relative expression level of IL-6, Klf4, Sox2, c-Myc, and Oct4 using Real-Time PCR and flow cytometry.

RESULTS

Wound healing assays represented low migratory ability in U-251 cells treated with BM-MSCs-miR-30c. Plus, apoptosis assay using Annexin V/7AAD showed an increased number of apoptotic U-251 cells following the treatment. miR-30 targeted IL-6 and induced apoptosis. It also impacted on the self-renewal and the anti-apoptotic cluster of genes, namely Klf4, Sox2, c-Myc, and Oct4, to induce apoptosis and dwindle the migration and invasion.

The Role of Tumor Microenvironment in Cancer Metastasis: Molecular Mechanisms and Therapeutic Opportunities

Simple Summary

Metastasis, the process by which cancer cells escape primary tumor site and colonize distant organs, is responsible for most cancer-related deaths. The tumor microenvironment (TME), comprises different cell types, including immune cells and cancer-associated fibroblasts, as well as structural elements, such as collagen and hyaluronan that constitute the extracellular matrix (ECM). Intratumoral interactions between the cellular and structural components of the TME regulate the aggressiveness, and dissemination of malignant cells and promote immune evasion. At the secondary site, the TME also facilitates escape from dormancy to enhance metastatic tumor outgrowth. Moreover, the ECM applies mechanical forces on tumors that contribute to hypoxia and cancer cell invasiveness whereas also hinders drug delivery and efficacy in both primary and metastatic sites. In this review, we summarize the latest developments regarding the role of the TME in cancer progression and discuss ongoing efforts to remodel the TME to stop metastasis in its tracks.

Abstract

The tumor microenvironment (TME) regulates essential tumor survival and promotion functions. Interactions between the cellular and structural components of the TME allow cancer cells to become invasive and disseminate from the primary site to distant locations, through a complex and multistep metastatic cascade. Tumor-associated M2-type macrophages have growth-promoting and immunosuppressive functions; mesenchymal cells mass produce exosomes that increase the migratory ability of cancer cells; cancer associated fibroblasts (CAFs) reorganize the surrounding matrix creating migration-guiding tracks for cancer cells. In addition, the tumor extracellular matrix (ECM) exerts determinant roles in disease progression and cancer cell migration and regulates therapeutic responses. The hypoxic conditions generated at the primary tumor force cancer cells to genetically and/or epigenetically adapt in order to survive and metastasize. In the circulation, cancer cells encounter platelets, immune cells, and cytokines in the blood microenvironment that facilitate their survival and transit. This review discusses the roles of different cellular and structural tumor components in regulating the metastatic process, targeting approaches using small molecule inhibitors, nanoparticles, manipulated exosomes, and miRNAs to inhibit tumor invasion as well as current and future strategies to remodel the TME and enhance treatment efficacy to block the detrimental process of metastasis.

Expedition into Exosome Biology: A Perspective of Progress from Discovery to Therapeutic Development

Exosomes are membrane-enclosed distinct cellular entities of endocytic origin that shuttle proteins and RNA molecules intercellularly for communication purposes. Their surface is embossed by a huge variety of proteins, some of which are used as diagnostic markers. Exosomes are being explored for potential drug delivery, although their therapeutic utilities are impeded by gaps in knowledge regarding their formation and function under physiological condition and by lack of methods capable of shedding light on intraluminal vesicle release at the target site. Nonetheless, exosomes offer a promising means of developing systems that enable the specific delivery of therapeutics in diseases like cancer. This review summarizes information on donor cell types, cargoes, cargo loading, routes of administration, and the engineering of exosomal surfaces for specific peptides that increase target specificity and as such, therapeutic delivery.