Exosomes from Bone Marrow Microenvironment-Derived Mesenchymal Stem Cells Affect CML Cells Growth and Promote Drug Resistance to Tyrosine Kinase Inhibitors

Harnessing the power of exosomes for diagnosis, prognosis, and treatment of hematological malignancies

Exosomes are small extracellular vesicles of endocytic origin released by various cell types. They consist of lipid bilayers containing macromolecules such as lipids, proteins, microRNAs, growth factors, cytokines, and carbohydrates. Exosomes play a critical role in the diagnosis and treatment of various diseases. For instance, exosome contents have been utilized as biomarkers in body fluids (urine, saliva, serum) to identify cancers, autoimmune diseases, and inflammatory conditions such as sepsis. Due to their small size and ability to reach tumor microenvironments, exosomes are also used as carriers for chemotherapeutic drugs in drug delivery systems. Furthermore, evidence indicates that malignant cells release exosomes into the tumor microenvironment, influencing immune cells in a paracrine manner. Additionally, immune cell-derived exosomes, such as those from Natural Killer (NK) cells or cytotoxic T lymphocytes (CTLs), show potential as therapeutic agents in treating malignancies like leukemia. This review discusses the diagnostic role of exosomes in various hematological malignancies and explores the therapeutic potential of immune cell-derived exosomes in these diseases.

Bone marrow mesenchymal stem cell exosomes suppress JAK/STAT signaling pathway in acute myeloid leukemia in vitro

INTRODUCTION

Despite advances in the treatment of acute myeloid leukemia (AML), refractory forms of this malignancy and relapse remain common. Therefore, development of novel, synergistic targeted therapies are needed urgently. Recently, mesenchymal stem cells (MSCs) have been shown to be effective in treating various diseases, with most of their therapeutic outcomes attributed to their exosomes. In the current study, we investigated the effects of bone marrow mesenchymal stem cell (BM-MSC) exosomes on the expression of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling genes involved in AML pathogenesis.

MATERIAL AND METHODS

Exosomes were isolated from BM-MSCs and confirmed using transmission electron microscopy, dynamic light scattering, and flow cytometry. Subsequently, the exosome concentration was estimated using the bicinchoninic acid assay, and HL-60 cells were cocultured with 100 µg/mL of BM-MSC exosomes. Finally, the JAK2, STAT3, and STAT5 expression levels were analyzed using qRT-PCR.

RESULTS

The exosome characterization results confirmed that most isolated nanoparticles exhibited a round morphology, expressed CD9, CD63, and CD81, which are specific protein markers for exosome identification, and ranged between 80 and 100 nm in diameter. Furthermore, qRT-PCR analysis revealed a significant downregulation of JAK2, STAT3, and STAT5 in HL-60 cells treated with 100 μg/mL of BM-MSC exosomes.

CONCLUSION

Since JAK/STAT signaling contributes to AML survival, our findings suggest that the downregulation of JAK/STAT genes by BM-MSC exosomes in leukemic cells may aid in designing a potent therapeutic strategy for AML treatment.

miR-16a-5p antagonizes FGF-2 in ligamentogenic differentiation of MSC: a new therapeutic perspective for tendon regeneration

With the increasing demand for exercise, the population of patients with ankle sprain to anterior talofibular ligament injury has the characteristics of a large base and high requirements for returning to sports, and how to promote the repair of damaged ligaments from a microscopic perspective is an urgent problem to be solved. In many studies, human amniotic mesenchymal stem cells have strong differentiation ability, and can be induced to continuously differentiate into ligament cells to achieve the purpose of repairing damaged ligaments. Human amniotic stem cells were extracted and cultured from human amniotic tissues, evaluated by cell identification and other techniques, and evaluated into ligament differentiation by toluidine blue, alizarin red, oil red O staining and detection of ligament cell differentiation, protein detection by Western blot, mRNA level by qPCR, and finally, the targeted binding relationship between miR-16a-5p and mRNA FGF2 was verified by double luciferase reporter assay. The expression of collagen type 1 (COL 1), collagen type 3 (COL3), SCX and MKX was increased by overexpression of mRNA FGF2, respectively, and miR-16a-5p had a targeted effect on FGF2 and regulated the ligamentous differentiation of human amniotic mesenchymal stem cells. We found that the regulatory effect of overexpressed mRNA FGF2 on mesenchymal stem cells could be inhibited by up-regulation of miR-16a-5p, while the knockdown of FGF2 could reverse the regulatory effect of miR-16a-5p inhibition on ligament-forming differentiation of human amniotic mesenchymal stem cells. In this study, we discovered the existence of the miR-16a-5p-FGF2 axis in human amniotic mesenchymal stem cells, and the differentiation of human amniotic mesenchymal stem cells into ligamentous cells can be regulated by regulating various links in this axis.

Oxaliplatin-induced upregulation of exosomal miR-424-3p derived from human bone marrow mesenchymal stem cells attenuates progression of gastric cancer cells

Chemotherapy, particularly with oxaliplatin, is a key treatment for advanced gastric cancer (GC), and exosomes derived from human bone marrow mesenchymal stem cells (hBM-MSCs) play a vital role in the tumor microenvironment. The study aims to elucidate the previously unexplored role of exosomes derived from hBM-MSCs in GC tumorigenesis, especially under the influence of chemotherapy. We conducted an experimental study, utilizing miRNA sequencing and biological experiments, to analyze the tumorigenicity of exosomal miR-424-3p secreted by hBM-MSCs and its target gene RHOXF2 in GC cell lines. The results were confirmed through experimentation using a xenograft mouse model. This study demonstrated the role of hBM-MSCs in the GC microenvironment, focusing on their epithelial-mesenchymal transition (EMT) facilitation through exosomes, which led to enhanced tumorigenicity in GC cells. Intriguingly, this pro-tumor effect was abrogated when hBM-MSCs were treated with oxaliplatin. Exosomal miRNA sequencing revealed that oxaliplatin can upregulate the levels of miR-424-3p in exosomes secreted by hBM-MSCs, thereby inhibiting the EMT process in GC cells. Furthermore, miR-424-3p was identified to target and downregulate RHOXF2 expression, impeding the malignant behavior of GC cells both in vitro and in the mouse model. These findings uncover a potential hidden mechanism of oxaliplatin's anti-tumor action and propose the delivery of miR-424-3p via exosomes as a promising avenue for anti-tumor therapy.

Adipogenic differentiation effect of human periodontal ligament stem cell initial cell density on autologous cells and human bone marrow stromal cells

Stem cells demonstrate differentiation and regulatory functions. In this discussion, we will explore the impacts of cell culture density on stem cell proliferation, adipogenesis, and regulatory abilities. This study aimed to investigate the impact of the initial culture density of human periodontal ligament stem cells (hPDLSCs) on the adipogenic differentiation of autologous cells. Our findings indicate that the proliferation rate of hPDLSCs increased with increasing initial cell density (0.5-8 × 104 cells/cm2). After adipogenic differentiation induced by different initial cell densities of hPDLSC, we found that the mean adipose concentration and the expression levels of lipoprotein lipase (LPL), CCAAT/enhancer binding protein α (CEBPα), and peroxisome proliferator-activated receptor γ (PPAR-γ) genes all increased with increasing cell density. To investigate the regulatory role of hPDLSCs in the adipogenic differentiation of other cells, we used secreted exocrine vesicles derived from hPDLSCs cultivated at different initial cell densities of 50 μg/mL to induce the adipogenic differentiation of human bone marrow stromal cells. We also found that the mean adipose concentration and expression of LPL, CEBPα, and PPARγ genes increased with increasing cell density, with an optimal culture density of 8 × 104 cells/cm2. This study provides a foundation for the application of adipogenic differentiation in stem cells.

The effect of bone marrow mesenchymal stromal cell exosomes on acute myeloid leukemia's biological functions: a focus on the potential role of LncRNAs

Acute myeloid leukemia represents a group of malignant blood disorders that originate from clonal over-proliferation and the differentiation failure of hematopoietic precursors, resulting in the accumulation of blasts in the bone marrow. Mesenchymal stromal cells (MSCs) have been shown to exert diverse effects on tumor cells through direct and indirect interaction. Exosomes, as one of the means of indirect intercellular communication, are released from different types of cells, including MSCs, and their various contents, such as lncRNAs, enable them to exert significant impacts on target cells. Our study aims to investigate the effects of BM-MSC exosomes on the cellular and molecular characterization of HL-60 AML cells, particularly detecting the alterations in the expression of lncRNAs involved in AML leukemogenesis, cell growth, drug resistance, and poor prognosis. BM-MSCs were cultured with serum-free culture media to isolate exosomes from their supernatants. The validation of exosomes was performed in three stages: morphological analysis using TEM, size evaluation using DLS, and CD marker identification using flow cytometry. Subsequently, the HL-60 AML cells were treated with isolated BM-MSC exosomes to determine the impact of their contents on leukemic cells. Cell metabolic activity was evaluated by the MTT assay, while cell cycle progression, apoptosis, ROS levels, and proliferation were assessed by flow cytometry. Furthermore, RT-qPCR was conducted to determine the expression levels of lncRNAs and apoptosis-, ROS-, and cell cycle-related genes. MTT assay and flow cytometry analysis revealed that BM-MSC exosomes considerably suppressed cell metabolic activity, proliferation, and cell cycle progression. Also, these exosomes could effectively increase apoptosis and ROS levels in HL-60 cells. The expression levels of p53, p21, BAX, and FOXO4 were increased, while the BCL2 and c-Myc levels decreased. MALAT1, HOTAIR, and H19 expression levels were also significantly decreased in treated HL-60 cells compared to their untreated counterparts. BM-MSC exosomes suppress cell cycle progression, proliferation, and metabolic activity while simultaneously elevating the ROS index and apoptosis ratio in HL-60 cells, likely by reducing the expression levels of MALAT1, HOTAIR, and H19. These findings suggest that BM-MSC exosomes might serve as potential supportive therapies for leukemia.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Extracellular vesicles in the Chronic Myeloid Leukemia scenario: an update about the shuttling of disease markers and therapeutic molecules

Extracellular vesicles (EVs) are various sets of cell-derived membranous structures containing lipids, nucleic acids, and proteins secreted by both eukaryotic and prokaryotic cells. It is now well recognized that EVs are key intercellular communication mediators, allowing the functional transfer of bioactive chemicals from one cell to another in both healthy and pathological pathways. It is evident that the condition of the producer cells heavily influences the composition of EVs. Hence, phenotypic changes in the parent cells are mirrored in the design of the secreted EVs. As a result, EVs have been investigated for a wide range of medicinal and diagnostic uses in different hematological diseases. EVs have only recently been studied in the context of Chronic Myeloid Leukemia (CML), a blood malignancy defined by the chromosomal rearrangement t(9;22) and the fusion gene BCR-ABL1. The findings range from the impact on pathogenesis to the possible use of EVs as medicinal chemical carriers. This review aims to provide for the first time an update on our understanding of EVs as carriers of CML biomarkers for minimal residual disease monitoring, therapy response, and its management, as well as the limited reports on the use of EVs as therapeutic shuttles for innovative treatment approaches.

Mesenchymal Stem Cell-Derived Extracellular Vesicles in Cancer Therapy Resistance: from Biology to Clinical Opportunity

Mesenchymal stem cells (MSCs) are a type of stromal cells characterized by their properties of self-renewal and multi-lineage differentiation, which make them prominent in regenerative medicine. MSCs have shown significant potential for the treatment of various diseases, primarily through the paracrine effects mediated by soluble factors, specifically extracellular vesicles (EVs). MSC-EVs play a crucial role in intercellular communication by transferring various bioactive substances, including proteins, RNA, DNA, and lipids, highlighting the contribution of MSC-EVs in regulating cancer development and progression. Remarkably, increasing evidence indicates the association between MSC-EVs and resistance to various types of cancer treatments, including radiotherapy, chemotherapy, targeted therapy, immunotherapy, and endocrinotherapy. In this review, we provide an overview of the recent advancements in the biogenesis, isolation, and characterization of MSC-EVs, with an emphasis on their functions in cancer therapy resistance. The clinical applications and future prospects of MSC-EVs for mitigating cancer therapy resistance and enhancing drug delivery are also discussed. Elucidating the role and mechanism of MSC-EVs in the development of treatment resistance in cancer, as well as evaluating the clinical significance of MSC-EVs, is crucial for advancing our understanding of tumor biology. Meanwhile, inform the development of effective treatment strategies for cancer patients in the future.

Mesenchymal stem cell-derived microRNAs: Friends or foes of tumor cells?

Mesenchymal stem cell (MSC)-dependent biological effects in the tumor microenvironment mainly rely on the activity of MSC-sourced microRNAs (MSC-miRNAs) which modulate protein synthesis in target tumor cells, endothelial cells and tumor-infiltrated immune cells, regulating their phenotype and function. Several MSC-sourced miRNAs (miR-221, miR-23b, miR-21-5p, miR-222/223, miR-15a miR-424, miR-30b, miR-30c) possess tumor-promoting properties and are able to enhance viability, invasiveness and metastatic potential of malignant cells, induce proliferation and sprouting of tumor endothelial cells and suppress effector functions of cytotoxic tumor-infiltrated immune cells, crucially contributing to the rapid growth and progression of tumor tissue. On the contrary, MSCs also produce "anti-tumorigenic" miRNAs (miR-100, miR-222-3p, miR-146b miR-302a, miR-338-5p, miR-100-5p and miR-1246) which suppress tumor growth and progression by: Up-regulating expression of chemoresistance-related genes in tumor cells, by suppressing neo-angiogenesis and by inducing generation of tumorotoxic phenotypes in tumor-infiltrated lymphocytes. In this review article, we summarize the current knowledge about molecular mechanisms that are responsible for MSC-miRNA-dependent alterations of intracellular signaling in tumor and immune cells and we discuss different insights regarding the therapeutic potential of MSC-derived miRNAs in cancer treatment.

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.

Bayesian analysis of the effect of exosomes in a mouse xenograft model of chronic myeloid leukemia

The aim of this work is to estimate the effect of Imatinib, exosomes, and Imatinib-exosomes mixture in chronic myeloid leukemia (CML). For this purpose, mathematical models based on Gompertzian and logistic growth differential equations were proposed. The models contained parameters representing the effects of the three components on CML proliferation. Parameters estimation was performed under the Bayesian statistical approach. Experimental data reported in the literature were used, corresponding to four trials of a human leukemia xenograft in BALB/c female rats over a period of forty days. The models were fitted to the following growth dynamics: normal tumor growth, growth with exosomes, growth with Imatinib, and growth with exosomes-Imatinib mixture. For the proposed logistic growth model, it was determined that when using Imatinib treatment the growth rate is 0.93 (95% CrI: 84.33-99.64) slower and reduces the tumor volume to approximately 10% (95% CrI : 8.67-10.81). In the presence of exosome treatment, the growth rate is 0.83 (95% CrI: 1.52-16.59) faster and the tumor volume is expanded by 40% (95% CrI: 25.36-57.28). Finally, in the presence of Imatinib-exosomes mixture treatment, the growth rate is 0.82 (95% CrI: 76.87-88.51) slower and the tumor volume is reduced by 95% (95% CrI: 86.76-99.85). It is concluded that the presence of exosomes partially inactivates the effect of the Imatinib drug on tumor growth in a mouse xenograft model.

Extracellular vesicles in hematological malignancies: EV-dence for reshaping the tumoral microenvironment

Following their discovery at the end of the 20th century, extracellular vesicles (EVs) ranging from 50-1,000 nm have proven to be paramount in the progression of many cancers, including hematological malignancies. EVs are a heterogeneous group of cell-derived membranous structures that include small EVs (commonly called exosomes) and large EVs (microparticles). They have been demonstrated to participate in multiple physiological and pathological processes by allowing exchange of biological material (including among others proteins, DNA and RNA) between cells. They are therefore a crucial way of intercellular communication. In this context, malignant cells can release these extracellular vesicles that can influence their microenvironment, induce the formation of a tumorigenic niche, and prepare and establish distant niches facilitating metastasis by significantly impacting the phenotypes of surrounding cells and turning them toward supportive roles. In addition, EVs are also able to manipulate the immune response and to establish an immunosuppressive microenvironment. This in turn allows for ideal conditions for heightened chemoresistance and increased disease burden. Here, we review the latest findings and reports studying the effects and therapeutic potential of extracellular vesicles in various hematological malignancies. The study of extracellular vesicles remains in its infancy; however, rapid advances in the analysis of these vesicles in the context of disease allow us to envision prospects to improve the detection and treatment of hematological malignancies.

Application of cell-derived exosomes in the hematological malignancies therapy

Exosomes are small membrane vesicles of endocytic origin that are produced by both tumor and normal cells and can be found in physiological fluids like plasma and cell culture supernatants. They include cytokines, growth factors, proteins, lipids, RNAs, and metabolites and are important intercellular communication controllers in several disorders. According to a vast amount of research, exosomes could support or inhibit tumor start and diffusion in a variety of solid and hematological malignancies by paracrine signaling. Exosomes are crucial therapeutic agents for a variety of illnesses, such as cancer and autoimmune diseases. This review discusses the most current and encouraging findings from in vitro and experimental in vivo research, as well as the scant number of ongoing clinical trials, with a focus on the impact of exosomes in the treatment of malignancies. Exosomes have great promise as carriers of medications, antagonists, genes, and other therapeutic materials that can be incorporated into their core in a variety of ways. Exosomes can also alter the metabolism of cancer cells, alter the activity of immunologic effectors, and alter non-coding RNAs, all of which can alter the tumor microenvironment and turn it from a pro-tumor to an anti-tumor milieu. This subject is covered in the current review, which also looks at how exosomes contribute to the onset and progression of hematological malignancies, as well as their importance in diagnosing and treating these conditions.

Stromal cells in the tumor microenvironment: accomplices of tumor progression?

The tumor microenvironment (TME) is made up of cells and extracellular matrix (non-cellular component), and cellular components include cancer cells and non-malignant cells such as immune cells and stromal cells. These three types of cells establish complex signals in the body and further influence tumor genesis, development, metastasis and participate in resistance to anti-tumor therapy. It has attracted scholars to study immune cells in TME due to the significant efficacy of immune checkpoint inhibitors (ICI) and chimeric antigen receptor T (CAR-T) in solid tumors and hematologic tumors. After more than 10 years of efforts, the role of immune cells in TME and the strategy of treating tumors based on immune cells have developed rapidly. Moreover, ICI have been recommended by guidelines as first- or second-line treatment strategies in a variety of tumors. At the same time, stromal cells is another major class of cellular components in TME, which also play a very important role in tumor metabolism, growth, metastasis, immune evasion and treatment resistance. Stromal cells can be recruited from neighboring non-cancerous host stromal cells and can also be formed by transdifferentiation from stromal cells to stromal cells or from tumor cells to stromal cells. Moreover, they participate in tumor genesis, development and drug resistance by secreting various factors and exosomes, participating in tumor angiogenesis and tumor metabolism, regulating the immune response in TME and extracellular matrix. However, with the deepening understanding of stromal cells, people found that stromal cells not only have the effect of promoting tumor but also can inhibit tumor in some cases. In this review, we will introduce the origin of stromal cells in TME as well as the role and specific mechanism of stromal cells in tumorigenesis and tumor development and strategies for treatment of tumors based on stromal cells. We will focus on tumor-associated fibroblasts (CAFs), mesenchymal stem cells (MSCs), tumor-associated adipocytes (CAAs), tumor endothelial cells (TECs) and pericytes (PCs) in stromal cells.

The Bone Marrow Immune Microenvironment in CML: Treatment Responses, Treatment-Free Remission, and Therapeutic Vulnerabilities

PURPOSE OF REVIEW

Tyrosine kinase inhibitors (TKIs) are very successful for the treatment of chronic myeloid leukaemia (CML) but are not curative in most patients due to persistence of TKI-resistant leukaemia stem cells (LSCs). The bone marrow immune microenvironment (BME) provides protection to the LSC through multidimensional interactions, driving therapy resistance, and highlighting the need to circumvent these protective niches therapeutically. This review updates the evidence for interactions between CML cells and the immune microenvironment with a view to identifying targetable therapeutic vulnerabilities and describes what is known about the role of immune regulation in treatment-free remission (TFR).

RECENT FINDINGS

Intracellular signalling downstream of the chemotactic CXCL12-CXCR4 axis, responsible for disrupted homing in CML, has been elucidated in LSCs, highlighting novel therapeutic opportunities. In addition, LSCs expressing CXCL12-cleaving surface protein CD26 were highly correlated with CML burden, building on existing evidence. Newer findings implicate the adhesion molecule CD44 in TKI resistance, while JAK/STAT-mediated resistance to TKIs may occur downstream of extrinsic signalling in the BME. Exosomal BME-LSC cross-communication has also been explored. Finally, further detail on the phenotypes of natural killer (NK) cells putatively involved in maintaining successful TFR has been published, and NK-based immunotherapies are discussed. Recent studies highlight and build on our understanding of the BME in CML persistence and TKI resistance, pinpointing therapeutically vulnerable interactions. Repurposing existing drugs and/or the development of novel inhibitors targeting these relationships may help to overcome these issues in TKI-resistant CML and be used as adjuvant therapy for sustained TFR.

EVs vs. EVs: MSCs and Tregs as a source of invisible possibilities

Extracellular vesicles (EVs) are produced by various cells and exist in most biological fluids. They play an important role in cell-cell signaling, immune response, and tumor metastasis, and also have theranostic potential. They deliver many functional biomolecules, including DNA, microRNAs (miRNA), messenger RNA (mRNA), long non-coding RNA (lncRNA), lipids, and proteins, thus affecting different physiological processes in target cells. Decreased immunogenicity compared to liposomes or viral vectors and the ability to cross through physiological barriers such as the blood-brain barrier make them an attractive and innovative option as diagnostic biomarkers and therapeutic carriers. Here, we highlighted two types of cells that can produce functional EVs, namely, mesenchymal stem/stromal cells (MSCs) and regulatory T cells (Tregs), discussing MSC/Treg-derived EV-based therapies for some specific diseases including acute respiratory distress syndrome (ARDS), autoimmune diseases, and cancer.

Extracellular Vesicles in Cancer Drug Resistance: Roles, Mechanisms, and Implications

Extracellular vesicles (EVs) are cell-derived nanosized vesicles that mediate cell-to-cell communication via transporting bioactive molecules and thus are critically involved in various physiological and pathological conditions. EVs contribute to different aspects of cancer progression, such as cancer growth, angiogenesis, metastasis, immune evasion, and drug resistance. EVs induce the resistance of cancer cells to chemotherapy, radiotherapy, targeted therapy, antiangiogenesis therapy, and immunotherapy by transferring specific cargos that affect drug efflux and regulate signaling pathways associated with epithelial-mesenchymal transition, autophagy, metabolism, and cancer stemness. In addition, EVs modulate the reciprocal interaction between cancer cells and noncancer cells in the tumor microenvironment (TME) to develop therapy resistance. EVs are detectable in many biofluids of cancer patients, and thus are regarded as novel biomarkers for monitoring therapy response and predicting prognosis. Moreover, EVs are suggested as promising targets and engineered as nanovehicles to deliver drugs for overcoming drug resistance in cancer therapy. In this review, the biological roles of EVs and their mechanisms of action in cancer drug resistance are summarized. The preclinical studies on using EVs in monitoring and overcoming cancer drug resistance are also discussed.

From bench to bedside: bridging the gaps in best practices for real-world chronic myeloid leukemia care

INTRODUCTION

Although tyrosine kinase inhibitors (TKIs) determined an improvement of responses and overall survival (OS) in chronic phase chronic myeloid leukemia (CP-CML) patients, some patients still fail the achievement of important milestones.

AREAS COVERED

In this review, we focus on the need of appropriate molecular and mutational monitoring during TKI treatment with new laboratory tools and on new compounds developed to counteract the unmet clinical need in CP-CML.

EXPERT OPINION

The appropriate identification of BCR::ABL1 dependent and independent mechanisms of resistance with Next Generation Sequencing (NGS) and digital droplet PCR (ddPCR) can allow to improve the therapeutic strategies and prevent the onset of a failure to treatment. New compounds have been recently approved or are still in investigational trials to improve the response in some critical forms of resistance and/or intolerance to available TKIs.

Construction of biomimetic cell-sheet-engineered periosteum with a double cell sheet to repair calvarial defects of rats

Background

The periosteum plays a crucial role in the development and injury healing process of bone. The purpose of this study was to construct a biomimetic periosteum with a double cell sheet for bone tissue regeneration.

Methods

In vitro, the human amniotic mesenchymal stem cells (hAMSCs) sheet was first fabricated by adding 50 ​μg/ml ascorbic acid to the cell sheet induction medium. Characterization of the hAMSCs sheet was tested by general observation, microscopic observation, live/dead staining, scanning electron microscopy (SEM) and hematoxylin and eosin (HE) staining. Afterwards, the osteogenic cell sheet and vascular cell sheet were constructed and evaluated by general observation, alkaline phosphatase (ALP) staining, Alizarin Red S staining, SEM, live/dead staining and CD31 immunofluorescent staining for characterization. Then, we prepared the double cell sheet. In vivo, rat calvarial defect model was introduced to verify the regeneration of bone defects treated by different methods. Calvarial defects (diameter: 4 ​mm) were created of Sprague–Dawley rats. The rats were randomly divided into 4 groups: the control group, the osteogenic cell sheet group, the vascular cell sheet group and the double cell sheet group. Macroscopic, micro-CT and histological evaluations of the regenerated bone were performed to assess the treatment results at 8 weeks and 12 weeks after surgery.

Results

In vitro, hAMSCs sheet was successfully prepared. The hAMSCs sheet consisted of a large number of live hAMSCs and abundant extracellular matrix (ECM) that secreted by hAMSCs, as evidenced by macroscopic/microscopic observation, live/dead staining, SEM and HE staining. Besides, the osteogenic cell sheet and the vascular cell sheet were successfully prepared, which were verified by general observation, ALP staining, Alizarin Red S staining, SEM and CD31 immunofluorescent staining. In vivo, the macroscopic observation and micro-CT results both demonstrated that the double cell sheet group had better effect on bone regeneration than other groups. In addition, histological assessments indicated that large amounts of new bone had formed in the calvarial defects and more mature collagen in the double cell sheet group.

Conclusion

The double cell sheet could promote to repair calvarial defects of rats and accelerate bone regeneration.

The translational potential of this article

We successfully constructed a biomimetic cell-sheet-engineered periosteum with a double cell sheet by a simple, low-cost and effective method. This biomimetic periosteum may be a promising therapeutic strategy for the treatment of bone defects, which may be used in clinic in the future.

Rapid detection of InDel within the KDM3B gene in five sheep breeds using the mathematical expectation (ME) method

Lysine demethylase 3B (KDM3B), a candidate gene associated with bone formation and growth, and differentiation of osteoblast, might affect the animal growth traits. Herein, the insertion/deletion (InDel) of the KDM3B gene was quickly detected in 882 sheep from five breeds using the mathematical expectation (ME) method. The results showed that there were two genotypes of 7-bp variation in KDM3B, including II (insertion/insertion) and ID (insertion/deletion), and the frequency of two genotypes varied among the five sheep breeds. Association analysis results demonstrated that the 7-bp indel was significantly associated with chest depth of LFT sheep (P = 0.012), and body weight (P = 0.006), body height (P = 0.030), chest depth (P = 0.043), chest circumference (P = 0.016), abdominal width (P = 0.035) and height at hip cross (P = 0.022) in LXBH sheep. Moreover, II genotype was the predominant genotype with excellent consistency in sheep growth traits (P < 0.05). Collectively, the above results suggest that this locus can be used as an effective molecular marker to improve the sheep growth traits and provide a scientific basis for the development of sheep breeding.

Emerging role of exosomes in cancer progression and tumor microenvironment remodeling

Cancer is one of the leading causes of death worldwide, and the factors responsible for its progression need to be elucidated. Exosomes are structures with an average size of 100 nm that can transport proteins, lipids, and nucleic acids. This review focuses on the role of exosomes in cancer progression and therapy. We discuss how exosomes are able to modulate components of the tumor microenvironment and influence proliferation and migration rates of cancer cells. We also highlight that, depending on their cargo, exosomes can suppress or promote tumor cell progression and can enhance or reduce cancer cell response to radio- and chemo-therapies. In addition, we describe how exosomes can trigger chronic inflammation and lead to immune evasion and tumor progression by focusing on their ability to transfer non-coding RNAs between cells and modulate other molecular signaling pathways such as PTEN and PI3K/Akt in cancer. Subsequently, we discuss the use of exosomes as carriers of anti-tumor agents and genetic tools to control cancer progression. We then discuss the role of tumor-derived exosomes in carcinogenesis. Finally, we devote a section to the study of exosomes as diagnostic and prognostic tools in clinical courses that is important for the treatment of cancer patients. This review provides a comprehensive understanding of the role of exosomes in cancer therapy, focusing on their therapeutic value in cancer progression and remodeling of the tumor microenvironment.

The Landscape of Exosome-Derived Non-Coding RNA in Leukemia

Leukemia is a group of life-threatening hematological malignancies which is currently incurable and often accompanied by drug resistance or disease relapse. Understanding the pathogenesis of leukemia and finding specific therapeutic targets and biomarkers is of great importance to improve the clinical efficacy of leukemia. Exosome-derived ncRNAs have been demonstrated as critical components of intercellular communication and function as key facilitators in the leukemia biological process. This review outlines the current investigations of exosomal ncRNAs (including miRNA, circRNA, and lncRNA) as important mediators of leukemia and potential therapeutic targets and biomarkers for leukemia treatment. Moreover, we generally analyze the prospects and challenges for exosomal ncRNAs from the aspects of research and clinical application.

Exosome-Mediated Response to Cancer Therapy: Modulation of Epigenetic Machinery

Exosomes, the extracellular vesicles produced in the endosomal compartments, facilitate the transportation of proteins as well as nucleic acids. Epigenetic modifications are now considered important for fine-tuning the response of cancer cells to various therapies, and the acquired resistance against targeted therapies often involves dysregulated epigenetic modifications. Depending on the constitution of their cargo, exosomes can affect several epigenetic events, thus impacting post-transcriptional regulations. Thus, a role of exosomes as facilitators of epigenetic modifications has come under increased scrutiny in recent years. Exosomes can deliver methyltransferases to recipient cells and, more importantly, non-coding RNAs, particularly microRNAs (miRNAs), represent an important exosome cargo that can affect the expression of several oncogenes and tumor suppressors, with a resulting impact on cancer therapy resistance. Exosomes often harbor other non-coding RNAs, such as long non-coding RNAs and circular RNAs that support resistance. The exosome-mediated transfer of all this cargo between cancer cells and their surrounding cells, especially tumor-associated macrophages and cancer-associated fibroblasts, has a profound effect on the sensitivity of cancer cells to several chemotherapeutics. This review focuses on the exosome-induced modulation of epigenetic events with resulting impact on sensitivity of cancer cells to various therapies, such as, tamoxifen, cisplatin, gemcitabine and tyrosine kinase inhibitors. A better understanding of the mechanisms by which exosomes can modulate response to therapy in cancer cells is critical for the development of novel therapeutic strategies to target cancer drug resistance.

Update on the role and utility of extracellular vesicles in hematological malignancies

Extracellular vesicles (EVs) are membrane-surrounded cellular particles released by virtually any cell type, containing numerous bioactive molecules, including lipids, proteins, and nucleic acids. EVs act as a very efficient intercellular communication system by releasing their content into target cells, thus affecting their fate and influencing several biological processes. EVs are released both in physiological and pathological conditions, including several types of cancers. In hematological malignancies (HM), EVs have emerged as new critical players, contributing to tumor-to-stroma, stroma-to-tumor, and tumor-to-tumor cell communication. Therefore, EVs have been shown to play a crucial role in the pathogenesis and clinical course of several HM, contributing to tumor development, progression, and drug resistance. Furthermore, tumor EVs can reprogram the bone marrow (BM) microenvironment and turn it into a sanctuary, in which cancer cells suppress both the normal hematopoiesis and the immunological anti-tumor activity, conferring a therapy-resistant phenotype. Due to their physicochemical characteristics and pro-tumor properties, EVs have been suggested as new diagnostic biomarkers, therapeutic targets, and pharmacological nanocarriers. This review aims to provide an update on the pathogenetic contribution and the putative therapeutic utility of EVs in hematological diseases.

Exosome-Mediated Therapeutic Strategies for Management of Solid and Hematological Malignancies

Exosomes are small membrane vesicles of endocytic origin containing cytokines, RNAs, growth factors, proteins, lipids, and metabolites. They have been identified as fundamental intercellular communication controllers in several diseases and an enormous volume of data confirmed that exosomes could either sustain or inhibit tumor onset and diffusion in diverse solid and hematological malignancies by paracrine signaling. Thus, exosomes might constitute a promising cell-free tumor treatment alternative. This review focuses on the effects of exosomes in the treatment of tumors, by discussing the most recent and promising data from in vitro and experimental in vivo studies and the few existing clinical trials. Exosomes are extremely promising as transporters of drugs, antagomir, genes, and other therapeutic substances that can be integrated into their core via different procedures. Moreover, exosomes can augment or inhibit non-coding RNAs, change the metabolism of cancer cells, and modify the function of immunologic effectors thus modifying the tumor microenvironment transforming it from pro-tumor to antitumor milieu. Here, we report the development of currently realized exosome modifiers that offer indications for the forthcoming elaboration of other more effective methods capable of enhancing the activity of the exosomes.

Mesenchymal stem cell-derived exosomes for gastrointestinal cancer

Gastrointestinal (GI) malignancies, a series of malignant conditions originating from the digestive system, include gastric cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer. GI cancers have been regarded as the leading cancer-related cause of death in recent years. Therefore, it is essential to develop effective treatment strategies for GI malignancies. Mesenchymal stem cells (MSCs), a type of distinct non-hematopoietic stem cells and an important component of the tumor microenvironment, play important roles in regulating GI cancer development and progression through multiple mechanisms, such as secreting cytokines and direct interactions. Currently, studies are focusing on the anti-cancer effect of MSCs on GI malignancies. However, the effects and functional mechanisms of MSC-derived exosomes on GI cancer are less studied. MSC-derived exosomes can regulate GI tumor growth, drug response, metastasis, and invasion through transplanting proteins and miRNA to tumor cells to activate the specific signal pathway. Besides, the MSC-derived exosomes are also seen as an important drug delivery system and have shown potential in anti-cancer treatment. This study aims to summarize the effect and biological functions of MSC-derived exosomes on the development of GI cancers and discuss their possible clinical applications for the treatment of GI malignancies.

Mesenchymal Stem Cell-Derived Exosomes and Their Potential Agents in Hematological Diseases

Mesenchymal stem cells (MSCs) are the most exploited stem cells with multilineage differentiation potential and immunomodulatory properties. Numerous lines of findings have reported their successful applications in a multitude of inflammatory conditions and immune disorders. However, it is currently discovered that these effects are mainly mediated in a paracrine manner by MSC-exosomes. Moreover, MSC-exosomes have been implicated in a wide variety of biological responses including immunomodulation, oxidative stress, tumor progression, and tissue regeneration. Meanwhile, they are reported to actively participate in various hematological diseases by the means of transferring different types of exosomal components to the target cells. Therefore, in this review, we briefly discuss the sources and biological features of MSCs and then illustrate the biogenesis and biological processes of MSC-exosomes. Of note, this paper especially highlights the latest research progress of MSC-exosomes in hematological diseases.

Resistance to Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia-From Molecular Mechanisms to Clinical Relevance

Simple Summary

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasia associated with a molecular alteration, the fusion gene BCR-ABL1, that encodes the tyrosine kinase oncoprotein BCR-ABL1. This led to the development of tyrosine kinase inhibitors (TKI), with Imatinib being the first TKI approved. Although the vast majority of CML patients respond to Imatinib, resistance to this targeted therapy contributes to therapeutic failure and relapse. Here we review the molecular mechanisms and other factors (e.g., patient adherence) involved in TKI resistance, the methodologies to access these mechanisms, and the possible therapeutic approaches to circumvent TKI resistance in CML.

Abstract

Resistance to targeted therapies is a complex and multifactorial process that culminates in the selection of a cancer clone with the ability to evade treatment. Chronic myeloid leukemia (CML) was the first malignancy recognized to be associated with a genetic alteration, the t(9;22)(q34;q11). This translocation originates the BCR-ABL1 fusion gene, encoding the cytoplasmic chimeric BCR-ABL1 protein that displays an abnormally high tyrosine kinase activity. Although the vast majority of patients with CML respond to Imatinib, a tyrosine kinase inhibitor (TKI), resistance might occur either de novo or during treatment. In CML, the TKI resistance mechanisms are usually subdivided into BCR-ABL1-dependent and independent mechanisms. Furthermore, patients’ compliance/adherence to therapy is critical to CML management. Techniques with enhanced sensitivity like NGS and dPCR, the use of artificial intelligence (AI) techniques, and the development of mathematical modeling and computational prediction methods could reveal the underlying mechanisms of drug resistance and facilitate the design of more effective treatment strategies for improving drug efficacy in CML patients. Here we review the molecular mechanisms and other factors involved in resistance to TKIs in CML and the new methodologies to access these mechanisms, and the therapeutic approaches to circumvent TKI resistance.

Metformin and Vitamin D Modulate Inflammation and Autophagy during Adipose-Derived Stem Cell Differentiation

Adipose-derived stem cells (ADSCs) came out from the regenerative medicine landscape for their ability to differentiate into several phenotypes, contributing to tissue regeneration both in vitro and in vivo. Dysregulation in stem cell recruitment and differentiation during adipogenesis is linked to a chronic low-grade inflammation and macrophage infiltration inside the adipose tissue, insulin resistance, cardiovascular disease and obesity. In the present paper we aimed to evaluate the role of metformin and vitamin D, alone or in combination, in modulating inflammation and autophagy in ADSCs during adipogenic commitment. ADSCs were cultured for 21 days in the presence of a specific adipogenic differentiation medium, together with metformin, or vitamin D, or both. We then analyzed the expression of FoxO1 and Heat Shock Proteins (HSP) and the secretion of proinflammatory cytokines IL-6 and TNF-α by ELISA. Autophagy was also assessed by specific Western blot analysis of ATG12, LC3B I, and LC3B II expression. Our results showed the ability of the conditioned media to modulate adipogenic differentiation, finely tuning the inflammatory response and autophagy. We observed a modulation in HSP mRNA levels, and a significant downregulation in cytokine secretion. Taken together, our findings suggest the possible application of these molecules in clinical practice to counteract uncontrolled lipogenesis and prevent obesity and obesity-related metabolic disorders.

MicroRNA-191 blocking the translocation of GLUT4 is involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway

Environmental exposure to arsenic can cause a variety of health problems. Epidemiological and experimental studies have established a diabetogenic role for arsenic, but the mechanisms responsible for arsenic-induced impairment of insulin action are unclear. MicroRNAs (miRNAs) are involved in various metabolic disorders, particularly in the development of insulin resistance. The present study investigated whether arsenite, an active form of arsenic, induces hepatic insulin resistance and the mechanisms underlying it. After male C57BL/6J mice were exposed to arsenite (0 or 20 ppm) in drinking water for 12 months, intraperitoneal glucose tolerance tests (IPGTTs) and insulin tolerance tests (ITTs) revealed an arsenite-induced glucose metabolism disorder. Hepatic glycogen levels were lower in arsenite-exposed mice. Further, for livers of mice exposed to arsenite, miR-191 levels were higher, and protein levels of insulin receptor substrate 1 (IRS1), p-IRS1, and phospho-protein kinase B (p-AKT) were lower. Further, glucose transporter 4 (GLUT4) had lower levels on the plasma membrane. For insulin-treated L-02 cells, arsenite decreased glucose consumption and glycogen levels, increased miR-191 levels, and inhibited the IRS1/AKT pathway and the translocation of GLUT4 from the cytoplasm to the plasma membrane. For insulin-treated L-02 cells, the decreases of glucose consumption, glycogen levels, GLUT4 on the plasma membrane, and p-AKT levels induced by arsenite were reversed by SC79 (agonist of AKT) and an miR-191 inhibitor; these effects caused by miR-191 inhibitor were restored by IRS1 siRNA. In insulin-treated L-02 cells, miR-191, via IRS1, was involved in the arsenite-induced decreases of glucose consumption and glycogen levels and in inhibition of the translocation of GLUT4. Thus, miR-191 blocking the translocation of GLUT4 was involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway. Our study reveals a mechanism for arsenite-induced hepatic insulin resistance, which provides clues for discovering biomarkers for the development of type 2 diabetes and for prevention and treatment of arsenic poisoning.

Exosomes from BM-MSCs promote acute myeloid leukemia cell proliferation, invasion and chemoresistance via upregulation of S100A4

Background

BM-MSCs play an important role in cancer development through the release of cytokines or exosomes. Studies have shown that extracellular exosomes derived from BM-MSCs are a key pro-invasive factor. However, how BM-MSC-exos influence AML cell proliferation, invasion and chemoresistance remains poorly understood.

Methods

We isolated exosomes from BM-MSCs and used electron microscopy, particle size separation and western blots to identify the exosomes. The invasion of leukemia cells was observed with a transwell assay. The stemness traits and chemoresistance of the leukemia cells were detected by FCM, colony formation and CCK-8 assays. TCGA database was used to investigate the prognostic relevance of S100A4 and its potential role in AML.

Results

In this study, we found that BM-MSC-exos increased the metastatic potential, maintained the stemness and contributed to the chemoresistance of leukemia cells. Mechanistically, BM-MSC-exos promoted the proliferation, invasion and chemoresistance of leukemia cells via upregulation of S100A4. Downregulating S100A4 clearly suppressed the proliferation, invasion, and chemoresistance of leukemia cells after treatment with BM-MSC-exos. Bioinformatic analysis with data in TCGA database showed that S100A4 was associated with poor prognosis in AML patients, and functional enrichment revealed its involvement in the processes of cell–cell adhesion and cytokine regulation.

Conclusions

S100A4 is vital in the BM-MSC-exo-driven proliferation, invasion and chemoresistance of leukemia cells and may serve as a potential target for leukemia therapy.