Therapeutic application of mesenchymal stem cells-derived extracellular vesicles in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the leading cause of cancer death globally. Resistance to therapy is a challenge for CRC treatment. Mesenchymal stem cells (MSCs) have become one of the furthermost effective approaches for tumor treatment due to their specific feature; however, their therapeutic function is controversial. Recently, extracellular vesicles (EVs) derived from MSCs (MSCs-EVs) have attracted extensive research attention due to their promising role in CRC treatment. EVs are cell-derived vesicles that transfer different biomolecules between cells, contributing to intracellular communication. MSCs-EVs can suppress CRC by delivering therapeutic agents to tumor cells. Several studies indicate that MSCs-EVs can serve as a drug delivery system for the treatment of different cancers. Various methods are used to modify (engineer) MSCs-EVs for loading therapeutic agents. Modified MSCs-EVs have improved specificity, targeting ability, and immunogenicity compared to synthetic carriers. Furthermore, CRC-EVs participate in regulating different cells, such as immune cells, fibroblasts, and endothelial cells, promoting tumorigenesis. MSCs-EVs-based therapy indicates a high potential in the treatment of cancer; however, the majority of studies have been conducted in the pre-clinical, and their clinical applications need further scrutiny. In this review, we describe the biogenesis of EVs, focusing on the effect of MSCs-EVs on CRC cells and CRC-derived EVs on other cells. Furthermore, MSCs-EVs as a drug delivery system for cancers is also reviewed, and perspectives regarding the therapeutic application of MSCs-EVs are discussed.     

Therapeutic mechanisms and routes of delivery of mesenchymal stem cells in veterinary medicine: A point of view

Mesenchymal stem cells (MSCs) represent an important tool in veterinary regenerative medicine due to their ability to home to injury sites and secrete molecules that regulate niches into regenerative microenvironments. Successful cell therapy depends on many factors, including choice of administration route and application of understanding of cell potency and their therapeutic mechanisms. In this point of view, the authors leverage the tumultuous history of the field to demonstrate the need for clinicians to continually update themselves as new discoveries are made in order to avoid misalignments in the future, especially regarding administration routes and dose frequency, as well as to explore recent insights into MSC plasticity, therapeutic mechanisms, and cell delivery systems.     

Mesenchymal stem cell-derived exosome: The likely game-changer in stem cell research

Stem cell research is a promising area of transplantation and regenerative medicine with tremendous potential for improving the clinical treatment and diagnostic options across a variety of conditions and enhancing understanding of human development. Over the past few decades, mesenchymal stem cell (MSCs) studies have exponentially increased with a promising outcome. However, regardless of the huge investment and the research attention given to stem cell research, FDA approval for clinical use is still lacking. Amid the challenges confronting stem cell research as a cell-based product, there appears to be evidence of superior effect and heightened potential success in its expressed vesicles, exosomes, as cell-free products. In addition to their highly desirable intrinsic biologically unique structural, compositional, and morphological characteristics, as well as predominant physiochemical stability and biocompatibility properties, exosomes can also be altered to enhance their therapeutic capability or diagnostic imaging potential via physical, chemical, and biological modification approaches. More importantly, the powerful therapeutic potential and superior biological functions of exosomes, particularly, regarding engineered exosomes as cell-free products, and their utilization in a new generation of nanomedicine treatment, vaccination, and diagnosis platforms, brings hope of a change in the near future. This viewpoint discusses the trend of stem cell research and why stem cell-derived exosomes could be the game-changer.     

Process Modeling of Ferrofluids Flow for Magnetic Targeting Drug Delivery

Among the proposed techniques for delivering drugs to specific sites within the human body, magnetic targeting drug delivery surpasses due to its non-invasive character and its high targeting efficiency. Although there have been some analyses theoretically for magnetic drug targeting, very few researchers have addressed the hydrodynamic models of magnetic fluids in the blood vessel of human body. This paper presents a mathematical model to describe the hydrodynamics of ferrofluids as drug carriers flowing in a blood vessel under the applied magnetic field. A 3D flow field of magnetic particles in a blood vessel model is numerically simulated in order to further understand clinical application of magnetic targeting drug delivery. Simulation results show that magnetic nanoparticles can be enriched in a target region depending on the applied magnetic field intensity. Magnetic resonance imaging conftrms the enrichment of ferrofluids in a desired body tissue of Sprague-Dawley rats. The simulation results coincide with those animal experiments. Results of the analysis provide the important information and can suggest strategies for improving delivery in favor of the clinical application.     

Adipose-derived mesenchymal stem/stromal cells: from the lab bench to the basic concepts for clinical translation

In the last years, much work has shown that the most effective repair system of the body is represented by stem cells, which are defined as undifferentiated precursors that own unlimited or prolonged self-renewal ability, which also have the potential to transform themselves into various cell types through differentiation.All tissues that form the body contain many different types of somatic cells, along with stem cells that are called ‘mesenchymal stem (or stromal) cells’ (MSC). In certain circumstances, some of these MSC migrate to injured tissues to replace dead cells or to undergo differentiation to repair it.The discovery of MSC has been an important step in regenerative medicine because of their high versatility. Moreover, the finding of a method to isolate MSC from adipose tissue, so called ‘adipose-derived mesenchymal stem cells’ (ASC), which share similar differentiation capabilities and isolation yield that is greater than other MSC, and less bioethical concerns compared to embryonic stem cells, have created self-praised publicity to procure almost any treatment with them. Here, we review the current techniques for isolation, culture and differentiation of human ASC (hASC), and describe them in detail. We also compile some advantages of the hASC over other stem cells, and provide some concepts that could help finding strategies to promote their therapeutic efficiency.     

Analysis of protein transport through the golgi in a reconstituted cell-free system

The processes which transport membrane proteins between compartments of the Golgi apparatus have been reconstituted in vitro using isolated Golgi fractions. This cell-free system allows a detailed analysis of protein transport not possible in intact cells. Transport of the membrane glycoprotein (G protein) of vesicular stomatitis virus (VSV) is measured from a “donor” to an “acceptor” Golgi fraction. The donor Golgi fraction is prepared from VSV-infected Chinese hamster ovary (CHO) mutant cells deficient in the glycosylation enzyme N-acetylglucosamine transferase I. “Acceptor” is prepared from uninfected wild-type CHO cells. Transport is measured by the addition of N-acetylglucosamine to G protein, which can occur only upon movement of G protein from donor to acceptor. Transport requires physiological pH and osmolarity, is dependent on nucleotide triphosphates, and is mediated by proteins both from cytosol and on the Golgi membranes. Protein movement is inhibited by the non-hydrolyzable GTP analogue, GTPγS. The process of transport proceeds through the budding, pinching off, targeting, and fusion of transport vesicles. In this system these vesicles are initially coated with a non-clathrin coat and are targeted with this coat intact. Several of the proteins which mediate transport have been characterized, and isolated to homogeneity. The successful development of this assay has led to the formulation of cell free assays for protein transport between other compartments. Comparison of these systems indicates that some common mechanisms of vesicular movement are used in transport between a variety of membrane compartments.     

Current engineering and clinical aspects of needle-free injectors: A review

Needle-free injectors can be used to achieve non-invasive drug delivery by impregnating biological barriers. They are considered as the future of drug delivery and therapeutic applications. The history of needle-free injectors dates back to the 1940s and these devices have been constantly evolving since then. Their operating principles and applications have been improved over the years. Herein, we review the current engineering mechanisms and clinical aspects of needle-free microjet injectors. The present study focuses on using engineering approaches to deal with various factors that affect the penetration and dispersion characteristics of the microjet.     

Mechanisms and applications of antitumor immunotherapy of responsive drug-loaded nanoparticles in breast cancer

During the chemotherapy of tumors, the cytotoxic effect of drugs is vital to kill tumor cells, and the delivery of a chemotherapeutic agent is of great importance for optimal therapeutic effects. The high in vivo clearance rate and low delivery efficiency of conventional chemotherapeutic agents affect the therapeutic effect. In recent years, the responsive drug delivery nanosystem has received increasing concern owing to its excellent biocompatibility, stable delivery performance, and controlled drug release strategies. To lucidly explain the cytocidal and immunotherapeutic effects of such responsive nanosystems in breast cancer, this review discusses the various stimuli and responses of drug-loaded liposomal nanosystems. The light/magnetic response of drug-loaded bionic membranes nanosystems and the heat/magnetic response of drug-loaded iron oxide nanosystems are also elaborated. Their cancer cell-killing efficacy and antitumor immunotherapeutic effects are also scrutinized.     

Tuning mesenchymal stem cell secretome therapeutic potential through mechanotransduction

Mesenchymal stem cells (MSCs) and their byproducts have been widely validated as potential therapeutic products for regenerative medicine. The therapeutic effects result mainly from the paracrine activity of MSCs, which consists of the secretion of bioactive molecules, whether dispersed in medium conditioned by cell culture or encapsulated in extracellular vesicles. The composition of the MSC secretome, which represents the set of these secreted cellular products, is crucial for the performance of the desired therapeutic functions. Different cell culture strategies have been employed to adjust the secretome composition of MSCs to obtain the best therapeutic responses for different clinical contexts. However, the manipulation of culture conditions has focused mainly on the use of different biochemical elements for the preconditioning of MSCs and less on the physical conditions of the cell culture environment. Herein, we offer our point of view regarding the importance of the physical properties of cell culture substrates and their mechanotransduction responses in preconditioning the MSCs secretome. We highlight the relevance of studying mechanotransduction events associating cell morphology and the modulation of gene expression to customize and expand the use of MSCs secretomes.     

Raloxifene-loaded and aptamer-bonded exosomes induce autophagic and apoptotic death in HeLa cells by enhancing the lysosomotropic effect

Background: Raloxifene, a selective estrogen receptor modulator, is also known to be a lysosomotropic agent. The bioavailability of raloxifene is around 2% due to extensive hepatic transport. Exosomes are nanosized vesicles that are naturally released from cells. Method: In this study, exosomes released from HeLa cervical cancer cells were loaded with raloxifene to increase its bioavailability, and an aptamer was attached to the exosome membrane for targeting only HeLa cells. Characterization of exosomes isolated from HeLa cells was performed by transmission electron microscopy, zeta sizer, and western blotting. In addition, the cytotoxic, apoptotic, autophagic, and lysosomotropic effects of the prepared Exo-Apt-Ral formulation on HeLa cervical cancer cells were investigated. Results: According to zeta analysis, the sizes of the empty exosome and Exo-Apt-Ral formulation were measured as 66 ± 12 and 120 ± 21 nm, respectively. There was a rise in the lysosomal permeability of HeLa cells after the Exo-Apt-Ral application. In addition, both apoptotic and autophagic death mechanisms were triggered in HeLa cells after the Exo-Apt-Ral application. Conclusion: This study showed that raloxifene functionalized by loading into aptamer-bound exosomes can be a new targeted drug carrier system for cervical cancer.     

Precise tissue bioengineering and niches of mesenchymal stem cells: Their size and hierarchy matter

Stem cell microterritories (niches), as a specialized part of the extracellular matrix (ECM), are considered an important target and tool for the development of new materials, medical implants, and devices. However, tissue bioengineering products that have stem cell niches of known size on the surface or in the bulk structure of artificial materials are practically unknown. This brief review attempts to draw attention to the problematic aspects of niches as specific parts of the ECM, such as their hierarchy and size for mesenchymal stromal/stem cells (MSCs). These parameters arise directly from numerous definitions of stem cell niches as specialized morphological microterritories found in various tissues. The authors of this review analyze the known information on the hierarchy of MSC microterritories by analogy with that of hematopoietic stem cells. Occasional reports on the size of artificial MSC niches compared to natural niche candidates are summarized. A consensus on a hierarchy and optimal range of niche sizes for MSCs and other stem cells is needed to accelerate the development of prototyping technologies and additive manufacturing in applications to precise tissue bioengineering and regenerative medicine.     

Mesenchymal stem cells-derived extracellular vesicles as ‘natural’ drug delivery system for tissue regeneration

Mesenchymal stem cells (MSCs) have abilities to mediate tissue protection through mechanisms of anti-apoptosis, anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation, differentiation and angiogenesis. These effects by MSCs are mediated by a variety of factors, including growth factors, cytokines and extracellular vesicles (EVs). Among these factors, EVs, containing proteins, mRNA and microRNAs (miRNA), may carry their contents into distant tissues with high stability. Therefore, the treatment with MSC-derived EVs may be promising as ‘natural’ drug delivery systems (DDS). Especially, the treatment of MSC-derived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries. The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection. Despite current several challenges for clinical use, it should open the next era of regenerative medicine for a variety of diseases. In this article, we highlight the therapeutic potential of MSC-derived EVs as ‘natural’ DDS and current challenges.     

dbSCI: A manually curated database of SARS-CoV-2 inhibitors for COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen of the ongoing coronavirus disease 2019 (COVID-19) global pandemic. Here, by centralizing published cell-based experiments, clinical trials, and virtual drug screening data from the NCBI PubMed database, we developed a database of SARS-CoV-2 inhibitors for COVID-19, dbSCI, which includes 234 SARS-CoV-2 inhibitors collected from publications based on cell-based experiments, 81 drugs of COVID-19 in clinical trials and 1305 potential SARS-CoV-2 inhibitors from bioinformatics analyses. dbSCI provides four major functions: (1) search the drug target or its inhibitor for SARS-CoV-2, (2) browse target/inhibitor information collected from cell experiments, clinical trials, and virtual drug screenings, (3) download, and (4) submit data. Each entry in dbSCI contains 18 types of information, including inhibitor/drug name, targeting protein, mechanism of inhibition, experimental technique, experimental sample type, and reference information. In summary, dbSCI provides a relatively comprehensive, credible repository for inhibitors/drugs against SARS-CoV-2 and their potential targeting mechanisms and it will be valuable for further studies to control COVID-19.     

<i>Ex vivo</i> cartilage explant model for the evaluation of chondrocyte-targeted exosomes

There is no efficient tracking system available for the therapeutic molecules delivered to cartilage. The dense matrix covering the cartilage surface is the main biological barrier that the therapeutic molecules must overcome. In this study, we aimed to establish a system that can dynamically and effectively track the therapeutic molecules delivered to cartilage. To this aim, we adopted bovine and human cartilage explants as ex vivo models for chondrocyte-targeted exosome dispersion. The efficiency of drug delivery was evaluated using frozen sections. The results of this study showed that the penetration and distribution of chondrocyte-targeted exosomes in cartilage explants can be tracked dynamically. Thus, ex vivo cartilage explants provide an effective and economic system to evaluate therapeutic drugs encapsulated in chondrocyte-targeted exosomes in preclinical studies.     

Rates of exocytosis and endocytosis in Arabidopsis root hairs and pollen tubes

Exocytosis and endocytosis are pivotal in many biological processes, but remain difficult to quantify. Here we combine a new algorithm for estimating vesicle size with a detailed morphological analysis of tip-growing cells, in which exocytosis is highly localized and therefore more readily quantified. Cell preservation was rendered as life-like as possible by rapid freezing. This allowed us to produce the first estimates of exocytosis rates in the root hairs and pollen tubes of the model plant Arabidopsis. To quantify exocytosis and endocytosis rates during cell growth, we measured the diameter of vesicles located in the tips of Arabidopsis root hairs and pollen tubes and the widths of cell walls and the cell lumen in longitudinal thin transmission electron microscopic sections. In addition, we measured growth velocities of Arabidopsis root hairs and pollen tubes, using video microscopy. The number of exocytotic vesicles required for cell wall expansion, and the amount of excess membrane inserted into the plasma membrane to be internalized, were estimated from the values that were obtained. The amount of excess membrane that is inserted into the plasma membrane during cell growth was estimated as 86.7% in root hairs and 79% in pollen tubes. This membrane has to be recycled by endocytosis. From counting of the total number of vesicles that is present in thin EM sections through the pollen tube tip, we estimated the average number of vesicles that is present in the tip of pollen tubes. By calculating the total amount of membrane and cell wall material that is required for continued cell growth, assuming that all vesicles are exocytotic, we estimated that pollen tubes continue to grow for 33 s when delivery of vesicles to the tip is inhibited. We arrested vesicle delivery to the tip by application of cytochalasin D. After cytochalasin D application, pollen tubes continued to grow for 30-40 s, which is in the same range as the estimated value of 33 s and shows that in this time frame, the availability of exocytotic vesicles is not a limiting factor.     

The versatility of mesenchymal stem cells: From regenerative medicine to COVID,what is next?

Mesenchymal stem cells (MSCs) play key roles in regenerative medicine by promoting tissue healing. MSCs can be isolated from different adult tissues and they are able to differentiate into several lineages. Due to their anti-inflammatory, angiogenic and immune-modulatory properties, MSCs are suitable for tissue engineering applications and, when associated with biomaterials, their benefits can be improved. Moreover, recently, MSCs have been studied for new clinical applications, such as in the treatment of patients with COVID-19. MSCs regenerative potential has been attributed to their secretome, which comprises extracellular matrix, soluble proteins and several elements, including the release of extracellular vesicles. Even though, in order to explore all their therapeutic potential, it is still necessary to advance in the investigation of their basic cell biology characteristics.     

Targeting the “undruggable” cancer driver genes: <i>Ras</i>, <i>myc</i>, and <i>tp53</i>

The term “undruggable” is to describe molecules that are not targetable or at least hard to target pharmacologically. Unfortunately, some targets with potent oncogenic activity fall into this category, and currently little is known about how to solve this problem, which largely hampered drug research on human cancers. Ras, as one of the most common oncogenes, was previously considered “undruggable”, but in recent years, a few small molecules like Sotorasib (AMG-510) have emerged and proved their targeted anti-cancer effects. Further, myc, as one of the most studied oncogenes, and tp53, being the most common tumor suppressor genes, are both considered “undruggable”. Many attempts have been made to target these “undruggable” targets, but little progress has been made yet. This article summarizes the current progress of direct and indirect targeting approaches for ras, myc, two oncogenes, and tp53, a tumor suppressor gene. These are potential therapeutic targets but are considered “undruggable”. We conclude with some emerging research approaches like proteolysis targeting chimeras (PROTACs), cancer vaccines, and artificial intelligence (AI)-based drug discovery, which might provide new cues for cancer intervention. Therefore, this review sets out to clarify the current status of targeted anti-cancer drug research, and the insights gained from this review may be of assistance to learn from experience and find new ideas in developing new chemicals that directly target such “undruggable” molecules.     

Salicylic acid permeation: a comparative study with different vehicles and membranes.

Considering the skin's function, different dermal pharmaceutical forms can be developed according to the type of therapeutic activity, active principle and excipients involved in the formulation, such as "transdermal preparations". In the present study, the permeation parameters of the non-steroidal anti-inflammatory drug, salicylic acid (SA) through synthetic membrane, polyvinyliden difluoride, and a biological membrane, egg shell membrane, with different vehicles, propylene glycol, isopropyl alcohol and carbopol gel, were determined. The reported physicochemical parameters of SA from CG were significantly higher than those obtained using PG and IP. This is attributed to the lipophilic nature of the vehicle that facilitates the release and penetration of the active principle, thus acting sinergically. The permeation profiles of SA allow us to state that permeation kinetics is of first order, so that the flux values obtained are in direct proportion to the specific rates of drug release.     

微纳米生物机器人与药物靶向递送技术

微纳米生物机器人与生物医学的结合可以解决传统医学无法解决的问题,从而显示出了其巨大的发展潜力。将微纳米生物机器人作为药物载体用于药物靶向递送技术,是机器人学、动力学、纳米科学、生物学和医学等多学科的交叉产物,对于治疗癌症、心血管疾病等具有特别的临床意义。但当前国内外的微纳米生物机器人及药物靶向治疗的整体发展水平仍处于基础研究阶段,还存在许多不足。介绍目前主要的药物靶向递送技术——磁性药物靶向及其实现机理和应用进展,总结目前存在的问题和可能解决的方法,提出以磁性红细胞作为机器人而组成的药物载体机器人群的概念,将纳米磁性红细胞机器人群应用到药物靶向递送技术上,由于与其他药物载体相比磁性载药红细胞具有强大的优势,使得它们可以很好地解决药物靶向递送过程中遇到的问题,并得到最优的、可控的、准确靶向及高浓度的药物递送机制。最后展望微纳米生物机器人在生物医学特别是药物靶向递送领域的未来前景及巨大的发展潜力。