HucMSC exosomes promoted imatinib-induced apoptosis in K562-R cells via a miR-145a-5p/USP6/GLS1 axis

Correlation analysis of bone marrow microvessel density and miRNA expression on drug resistance in patients with chronic myelogenous leukemia after tyrosine kinase inhibitor treatment

OBJECTIVE

This study analyzed the relationship between bone marrow microvessel density (MVD) and the expression of four miRNAs with chronic myelogenous leukemia (CML) resistance after tyrosine kinase inhibitor (TKI) treatment.

METHODS

234 CML patients were divided into resistance and non-resistance groups in terms of the results of the 5-year follow-up. Patients were divided into the Optimum response group and the Warning/Failure group based on TKI response. MVD was determined by immunohistochemistry, and the expression levels of four miRNAs (miR-106a, miR-155, miR-146a, and miR-340) in bone marrow biopsy specimens were examined by qPCR. We evaluated the association of MVD with four miRNAs and them predictive value for CML resistance after TKI treatment.

RESULTS

The MVD and the levels of miR-106a, miR-155, and miR-146a were significantly higher while the miR-340 level was lower in the resistance group than the non-resistance group. Besides, MVD had a significant correlation with the levels of miR-340 and miR-155. According to the results of survival analysis, MVD as well as miR-340 and miR-155 levels were observably correlated with 5-year survival of patients without TKI resistance. The results of the ROC curve indicated that the MVD, miR-106a, miR-340, and miR-155 had good predictive accuracy for CML resistance after TKI treatment. As for the results of multivariate analysis, disease stage, risk level (high risk), high MVD, low miR-340 expression, and high miR-155 expression were all independent risk factors for CML resistance.

CONCLUSION

MVD and the expression of miR-340 and miR-155 are closely associated with CML resistance after TKI treatment.

Exploiting the potential of the ubiquitin-proteasome system in overcoming tyrosine kinase inhibitor resistance in chronic myeloid leukemia

The advent of tyrosine kinase inhibitors (TKI) targeting BCR-ABL has drastically changed the treatment approach of chronic myeloid leukemia (CML), greatly prolonged the life of CML patients, and improved their prognosis. However, TKI resistance is still a major problem with CML patients, reducing the efficacy of treatment and their quality of life. TKI resistance is mainly divided into BCR-ABL-dependent and BCR-ABL-independent resistance. Now, the main clinical strategy addressing TKI resistance is to switch to newly developed TKIs. However, data have shown that these new drugs may cause serious adverse reactions and intolerance and cannot address all resistance mutations. Therefore, finding new therapeutic targets to overcome TKI resistance is crucial and the ubiquitin-proteasome system (UPS) has emerged as a focus. The UPS mediates the degradation of most proteins in organisms and controls a wide range of physiological processes. In recent years, the study of UPS in hematological malignant tumors has resulted in effective treatments, such as bortezomib in the treatment of multiple myeloma and mantle cell lymphoma. In CML, the components of UPS cooperate or antagonize the efficacy of TKI by directly or indirectly affecting the ubiquitination of BCR-ABL, interfering with CML-related signaling pathways, and negatively or positively affecting leukemia stem cells. Some of these molecules may help overcome TKI resistance and treat CML. In this review, the mechanism of TKI resistance is briefly described, the components of UPS are introduced, existing studies on UPS participating in TKI resistance are listed, and UPS as the therapeutic target and strategies are discussed.

Ubiquitin-specific proteases (USPs) in leukemia: a systematic review

BACKGROUND

Leukemia, a type of blood cell cancer, is categorized by the type of white blood cells affected (lymphocytes or myeloid cells) and disease progression (acute or chronic). In 2020, it ranked 15th among the most diagnosed cancers and 11th in cancer-related deaths globally, with 474,519 new cases and 311,594 deaths (GLOBOCAN2020). Research into leukemia's development mechanisms may lead to new treatments. Ubiquitin-specific proteases (USPs), a family of deubiquitinating enzymes, play critical roles in various biological processes, with both tumor-suppressive and oncogenic functions, though a comprehensive understanding is still needed.

AIM

This systematic review aimed to provide a comprehensive review of how Ubiquitin-specific proteases are involved in pathogenesis of different types of leukemia.

METHODS

We systematically searched the MEDLINE (via PubMed), Scopus, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) to identify relevant studies focusing on the role of USPs in leukemia. Data from selected articles were extracted, synthesized, and organized to present a coherent overview of the subject matter.

RESULTS

The review highlights the crucial roles of USPs in chromosomal aberrations, cell proliferation, differentiation, apoptosis, cell cycle regulation, DNA repair, and drug resistance. USP activity significantly impacts leukemia progression, inhibition, and chemotherapy sensitivity, suggesting personalized diagnostic and therapeutic approaches. Ubiquitin-specific proteases also regulate gene expression, protein stability, complex formation, histone deubiquitination, and protein repositioning in specific leukemia cell types.

CONCLUSION

The diagnostic, prognostic, and therapeutic implications associated with ubiquitin-specific proteases (USPs) hold significant promise and the potential to transform leukemia management, ultimately improving patient outcomes.

USP6 and circCYFIP2 target oncoprotein GOLPH3 for deubiquitination and induce platinum resistance in colon cancer

GOLPH3 has been identified as an oncoprotein, playing a crucial role on progression and chemoresistancein of colon adenocarcinoma (COAD). However, it is still unclear the regulation of GOLPH3 expression at protein level. We discovered ubiquitin-specific proteases 6 (USP6) directly regulated the deubiquitination of the GOLPH3 protein and enhanced its stability in COAD. Overexpression of USP6 promoted COAD cell viability, inhibited apoptosis, and accelerated the growth of transplanted tumors growth in vitro and in vivo by deubiquitinating GOLPH3. Additionally, circCYFIP2 showed high expression levels in DDP-resistant colon cancer cells, promoting the cell proliferation. Mechanically, circCYFIP2 binds to both GOLPH3 protein and USP6, strengthening the interaction between GOLPH3 and USP6, and consequently induced DDP resistance in vitro and in vivo. In conclusion, USP6 operates as a deubiquitinase, targeting the GOLPH3 protein in COAD and enhancing its stability. Meanwhile, circCYFIP2 is crucial for the deubiquitination of GOLPH3 protein mediated by USP6 and acts as a scaffold to confer platinum resistance. The discovery of circCYFIP2/USP6/GOLPH3 pathway offers a potential target for overcoming chemoresistance in COAD.

Drug resistance mechanisms and treatment strategies mediated by Ubiquitin-Specific Proteases (USPs) in cancers: new directions and therapeutic options

Drug resistance represents a significant obstacle in cancer treatment, underscoring the need for the discovery of novel therapeutic targets. Ubiquitin-specific proteases (USPs), a subclass of deubiquitinating enzymes, play a pivotal role in protein deubiquitination. As scientific research advances, USPs have been recognized as key regulators of drug resistance across a spectrum of treatment modalities, including chemotherapy, targeted therapy, immunotherapy, and radiotherapy. This comprehensive review examines the complex relationship between USPs and drug resistance mechanisms, focusing on specific treatment strategies and highlighting the influence of USPs on DNA damage repair, apoptosis, characteristics of cancer stem cells, immune evasion, and other crucial biological functions. Additionally, the review highlights the potential clinical significance of USP inhibitors as a means to counter drug resistance in cancer treatment. By inhibiting particular USP, cancer cells can become more susceptible to a variety of anti-cancer drugs. The integration of USP inhibitors with current anti-cancer therapies offers a promising strategy to circumvent drug resistance. Therefore, this review emphasizes the importance of USPs as viable therapeutic targets and offers insight into fruitful directions for future research and drug development. Targeting USPs presents an effective method to combat drug resistance across various cancer types, leading to enhanced treatment strategies and better patient outcomes.

Ferritin-nanocaged aggregation-induced emission nanoaggregates for NIR-II fluorescence-guided noninvasive, controllable male contraception

Controllable contraception in male animals was demonstrated through the utilization of gold nanorods' photothermal effect to accomplish mild testicular hyperthermia. However, the challenges arising from testicular administration and the non-biodegradability of nanoparticles hinder further clinical implementation. Therefore, a straightforward, non-invasive, and enhanced contraception approach is required. This study explores the utilization of human heavy chain ferritin (HFn) nanocarriers loaded with aggregation-induced emission luminogens (AIEgens) for noninvasive, controllable male contraception guided by Near-Infrared-II (NIR-II) fluorescence imaging. The HFn-caged AIEgens (HFn@BBT) are delivered via intravenous injection and activated by near-infrared irradiation. Lower hyperthermia treatment induces partial damage to the testes and seminiferous tubules, reducing fertility indices by approximately 100% on the 7th day, which gradually recovers to 80% on the 60th day. Conversely, implementation of elevated hyperthermia therapy causes total destruction of both testes and seminiferous tubules, leading to a complete loss of fertility on the 60th day. Additionally, the use of AIEgens in NIR-II imaging offers improved fluorescence efficiency and penetration depth. The findings of this study hold significant promise for the advancement of safe and effective male contraceptive methods, addressing the need for noninvasive and controllable approaches to reproductive health and population control.

Leukemia cancer cells and immune cells derived-exosomes: Possible roles in leukemia progression and therapy

Exosomes have a significant impact on tumor survival, proliferation, metastasis, and recurrence. They also open up new therapeutic options and aid in the pathological identification and diagnosis of cancers. Exosomes have been shown in numerous studies to be essential for facilitating cell-to-cell communication. In B-cell hematological malignancies, the proteins and RNAs that are encased by circulating exosomes are thought to represent prospective sources for therapeutic drugs as well as biomarkers for diagnosis and prognosis. Additionally, exosomes can offer a "snapshot" of the tumor and the metastatic environment at any given point in time. In this review study, we concluded that leukemia-derived exosomes could be utilized as prognostic, diagnostic, and therapeutic biomarkers for individuals suffering from leukemia. Moreover, clinical studies have demonstrated that immune cells like dendritic cells create exosomes, which have the ability to activate the immune system against leukemia.

Role of microRNA-146a in cancer development by regulating apoptosis

Despite great advances in diagnostic and treatment options for cancer, like chemotherapy surgery, and radiation therapy it continues to remain a major global health concern. Further research is necessary to find new biomarkers and possible treatment methods for cancer. MicroRNAs (miRNAs), tiny non-coding RNAs found naturally in the body, can influence the activity of several target genes. These genes are often disturbed in diseases like cancer, which perturbs functions like differentiation, cell division, cell cycle, apoptosis and proliferation. MiR-146a is a commonly and widely used miRNA that is often overexpressed in malignant tumors. The expression of miR-146a has been correlated with many pathological and physiological changes in cancer cells, such as the regulation of various cell death paths. It's been established that the control of cell death pathways has a huge influence on cancer progression. To improve our understanding of the interrelationship between miRNAs and cancer cell apoptosis, it's necessary to explore the impact of miRNAs through the alteration in their expression levels. Research has demonstrated that the appearance and spread of cancer can be mitigated by moderating the expression of certain miRNA - a commencement of treatment that presents a hopeful approach in managing cancer. Consequently, it is essential to explore the implications of miR-146a with respect to inducing different forms of tumor cell death, and evaluate its potential to serve as a target for improved chemotherapy outcomes. Through this review, we provide an outline of miR-146a's biogenesis and function, as well as its significant involvement in apoptosis. As well, we investigate the effects of exosomal miR-146a on the promotion of apoptosis in cancer cells and look into how it could possibly help combat chemotherapeutic resistance.

Exosomal circ_0037104 derived from Hu-MSCs inhibits cholangiocarcinoma progression by sponging miR-620 and targeting AFAP1

Exosomes are membrane-enclosed nanovesicles that shuttle active cargoes, such as circular RNAs (circRNAs) and microRNAs (miRNAs), between different cells. Human umbilical cord-derived mesenchymal stem cells (Hu-MSCs) can migrate to tumor sites and exert complex functions throughout tumor progression. In this study, we successfully isolated Hu-MSCs from human umbilical cords based on their surface marker expression. Hu-MSC-derived exosomes significantly reduced the invasion, migration, and proliferation of cholangiocarcinoma (CCA) cells. Furthermore, circ_0037104 was downregulated in CCA and inhibited the proliferation and metastasis of CCA cells. Then, we investigated the effect of Hu-MSC-derived exosomal circ_0037104 on CCA. Circ_0037104 mainly regulates miR-620 and enhances APAF1 expression, inhibiting CCA cell proliferation and metastasis. Overall, Hu-MSC exosomal circ_0037104 contributes to the progression and stemness of CCA cells via miR-620/APAF1. In conclusion, Hu-MSC-derived exosomal circ_0037104 sponges miR-620 directly and negatively targets APAF1 to suppress CCA.

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.

Analysis of the Inhibitory Effect of hsa-miR-145-5p and hsa-miR-203a-5p on Imatinib-Resistant K562 Cells by GC/MS Metabolomics Method

Imatinib (IM) resistance is considered to be a significant challenge in the management of chronic myeloid leukemia (CML). Previous studies have reported that hsa-miR-145-5p and hsa-miR-203a-5p can overcome IM resistance and hsa-miR-203a-5p can alter glutathione metabolism in IM-resistant cells. The purpose of this study was to examine whether hsa-miR-145-5p or hsa-miR-203a-5p counters IM resistance by targeting the overall metabolic profile of IM-resistant K562 cells. The metablic profiling of cell lysates obtained from IM-sensitive, IM-resistant, and miR-transfected IM-resistant K562 cells was carried out using the GC-MS technique. Overall, 75 major metabolites were detected, of which 32 were present in all samples. The pathway analysis of MetaboAnalyst 5.0 revealed that the majorly enriched pathways included glucose metabolism, fatty acid biosynthesis, lipogenesis, and nucleotide metabolism. Eleven of identified metabolites, l-glutamine, l-glutamic acid, l-lactic acid, phosphoric acid, 9,12-octadecadienoic acid, 9-octadecenoic acid, myristic acid, palmitic acid, cholesterol, and β-alanine, appeared in enriched pathways. IM-resistant cells had comparatively higher concentrations of all of these metabolites. Notably, the introduction of hsa-miR-145-5p or hsa-miR-203a-5p into resistant cells resulted in a decrease in levels of these metabolites. The efficacy of miR-203a-5p was particularly remarkable in comparison with miR-145-5p, as evidenced by partial least-squares-discriminant analysis (PLS-DA), which showed a high level of similarity in metabolic profile between IM-sensitive K562 cells and IM-resistant cells transfected with hsa-miR-203a-5p. The results indicate that GC-MS-based metabolic profiling has the potential to distinguish between drug-resistant and -sensitive cells. This approach can also be used to routinely monitor therapeutic response in drug-resistant patients, thus, enabling personalized therapy.

Role of cancer-educated mesenchymal stromal cells on tumor progression

The malignant tumor is the main cause of human deaths worldwide. Current therapies focusing on the tumor itself have achieved unprecedented benefits. Various pro-tumorigenic factors in the tumor microenvironment (TME) could abolish the effect of cancer therapy. Mesenchymal stromal cells (MSCs) are one of the substantial components in the tumor microenvironment, contributing to tumor progression. However, MSCs are not inherently tumor-promoting. Indeed, they acquire pro-tumorigenic properties under the education of the TME. We herein review how various elements in the TME including tumor cells, immune cells, pro-inflammatory factors, hypoxia, and extracellular matrix influence the biological characteristics of MSCs through complex interactions and demonstrate the underlying mechanisms. We also highlight the importance of tumor-associated mesenchymal stromal cells (TA-MSCs) in promoting tumor progression. Our review gives a new insight into the TA-MSCs as a potential tumor therapeutic target. It is anticipated that subverting MSCs education will facilitate the outbreak of therapeutic strategies against tumors.

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.

hucMSCs treatment prevents pulmonary fibrosis by reducing circANKRD42-YAP1-mediated mechanical stiffness

Idiopathic pulmonary fibrosis (IPF) is a fibrosing interstitial pneumonia of unknown cause. The most typical characteristic of IPF is gradual weakening of pulmonary elasticity and increase in hardness/rigidity with aging. This study aims to identify a novel treatment approach for IPF and explore mechanism of mechanical stiffness underlying human umbilical cord mesenchymal stem cells (hucMSCs) therapy. Target ability of hucMSCs was examined by labeling with cell membrane dye Dil. Anti-pulmonary fibrosis effect of hucMSCs therapy by reducing mechanical stiffness was evaluated by lung function analysis and MicroCT imaging system and atomic force microscope in vivo and in vitro. Results showed that stiff environment of fibrogenesis caused cells to establish a mechanical connection between cytoplasm and nucleus, initiating expression of related mechanical genes such as Myo1c and F-actin. HucMSCs treatment blocked force transmission and reduced mechanical force. For further exploration of mechanism, ATGGAG was mutated to CTTGCG (the binding site of miR-136-5p) in the full-length sequence of circANKRD42. Wildtype and mutant plasmids of circANKRD42 were packaged into adenovirus vectors and sprayed into lungs of mice. Mechanistic dissection revealed that hucMSCs treatment repressed circANKRD42 reverse splicing biogenesis by inhibiting hnRNP L, which in turn promoted miR-136-5p binds to 3'-Untranslated Region (3'-UTR) of YAP1 mRNA directly, thus inhibiting translation of YAP1 and reducing YAP1 protein entering nucleus. The condition repressed expression of related mechanical genes to block force transmission and reduce mechanical forces. The mechanosensing mechanism mediated directly by circANKRD42-YAP1 axis in hucMSCs treatment, which has potential general applicability in IPF treatment.

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.

Pancreatic stellate cells promote pancreatic β-cell death through exosomal microRNA transfer in hypoxia

Hypoxia in pancreatic islets (islet hypoxia) can occur in type 2 diabetes mellitus. Previously, our in vitro experiments demonstrated that pancreatic stellate cells (PSCs) within the islet are activated in hypoxia, promoting pancreatic β-cell death. Here, we aimed to demonstrate the in vivo activation of intra-islet PSCs and investigate the mechanism of PSC-induced β-cell death in hypoxia. A novel in vivo model of islet hypoxia was established by injecting fluorescent microspheres into a carotid artery of Balb/c mice (Microsphere mice). The intraperitoneal glucose tolerance (IPGTT) was performed, and pancreatic tissues were stained for insulin expression after tissue clearing. Pimonidazole staining was also performed in the pancreas to detect the presence of hypoxia in islets. Next, primary PSCs were isolated and cultured from Balb/c mice. Exosomes were isolated from culture media from PSCs cultured in hypoxia (1% oxygen). MicroRNAs (miRNAs) were prepared from exosomes from PSCs, and miRNA expression profiles were analyzed by miRNA sequencing. Several miRNAs were overexpressed in islets using miRNA mimics. Two weeks after injection of microspheres, the Microsphere mice showed worsening of glucose tolerance in IPGTT. Later, cataracts were developed in the eyes of the mice. The pancreas showed that the areas, perimeters, and diameters of insulin-positive cells decreased in Microsphere mice. Pimonidazole adducts were detected in the islets of these mice, indicating the presence of islet hypoxia. In addition, α-smooth muscle actin-positive areas per islet were higher in Microsphere mice, confirming the in vivo activation of intra-islet PSCs in hypoxia. Mouse islets cultured with exosomes isolated from PSCs cultured in hypoxia showed a decrease in cell viability. The exosomes contained a variety of miRNAs, of which miR-23a-3p was found to notably increase β-cell death through apoptosis. Together, our in vivo and in vitro data provide evidence to support that PSCs within the islets are activated in hypoxia and promote β-cell death through exosomal miRNA transfer, which may contribute to the progression of type 2 diabetes mellitus.

Exosomal delivery of 7SK long non-coding RNA suppresses viability, proliferation, aggressiveness and tumorigenicity in triple negative breast cancer cells

AIMS

RN7SK (7SK), a highly conserved non-coding RNA, serves as a transcription regulator via interaction with a few proteins. Despite increasing evidences which support the cancer-promoting roles of 7SK-interacting proteins, limited reports address the direct link between 7SK and cancer. To test the hypothetic suppression of cancer by overexpression of 7SK, the effects of exosomal 7SK delivery on cancer phenotypes were studied.

MATERIALS AND METHODS

Exosomes derived from human mesenchymal stem cells were loaded with 7SK (Exo-7SK). MDA-MB-231, triple negative breast cancer (TNBC), cell line was treated with Exo-7sk. Expression levels of 7SK were evaluated by qPCR. Cell viability was assessed via MTT and Annexin V/PI assays as well as qPCR assessment of apoptosis-regulating genes. Cell proliferation was evaluated by growth curve analysis, colony formation and cell cycle assays. Aggressiveness of TNBCs was evaluated via transwell migration and invasion assays and qPCR assessment of genes regulating epithelial to mesenchymal transition (EMT). Moreover, tumor formation ability was assessed using a nude mice xenograft model.

KEY FINDINGS

Treatment of MDA-MB-231 cells with Exo-7SK resulted in efficient overexpression of 7SK; reduced viability; altered transcription levels of apoptosis-regulating genes; reduced proliferation; reduced migration and invasion; altered transcription of EMT-regulating genes; and reduced in vivo tumor formation ability. Finally, Exo-7SK reduced mRNA levels of HMGA1, a 7SK interacting protein with master gene regulatory and cancer promoting roles, and its bioinformatically-selected cancer promoting target genes.

SIGNIFICANCE

Altogether, as a proof of the concept, our findings suggest that exosomal delivery of 7SK may suppress cancer phenotypes via downregulation of HMGA1.

Alone and together: current approaches to targeting glutaminase enzymes as part of anti-cancer therapies

Metabolic reprogramming is a major hallmark of malignant transformation in cancer, and part of the so-called Warburg effect, in which the upregulation of glutamine catabolism plays a major role. The glutaminase enzymes convert glutamine to glutamate, which initiates this pathway. Inhibition of different forms of glutaminase (KGA, GAC, or LGA) demonstrated potential as an emerging anti-cancer therapeutic strategy. The regulation of these enzymes, and the molecular basis for their inhibition, have been the focus of much recent research. This review will explore the recent progress in understanding the molecular basis for activation and inhibition of different forms of glutaminase, as well as the recent focus on combination therapies of glutaminase inhibitors with other anti-cancer drugs.

Tumour‑derived exosomes and their emerging roles in leukaemia (Review)

Exosomes are small vesicles with a diameter of ~40-100 nm that are secreted by the majority of endogenous cells under normal and pathological conditions. They contain abundant proteins, lipids, microRNAs, and biomolecules such as signal transduction molecules, adhesion factors and cytoskeletal proteins, and play an important role in exchanging materials and transmitting information between cells. Recent studies have shown that exosomes are involved in the pathophysiology of leukaemia by affecting the bone marrow microenvironment, apoptosis, tumour angiogenesis, immune escape and chemotherapy resistance. Furthermore, exosomes are potential biomarkers and drug carriers for leukaemia, impacting the diagnosis and treatment of leukaemia. The present study describes the biogenesis and general characteristics of exosomes, and then highlight the emerging roles of exosomes in different types of leukaemia. Finally, the value of clinical application of exosomes as biomarkers and drug carriers is discussed with the aim to provide novel strategies for the treatment of leukaemia.

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Alleviate Diffuse Alveolar Hemorrhage Associated with Systemic Lupus Erythematosus in Mice by Promoting M2 Macrophage Polarization via the microRNA-146a-5p/NOTCH1 Axis

Systemic lupus erythematosus (SLE)-associated diffuse alveolar hemorrhage (DAH) is a rare but extremely harmful condition. The current study sought to dissect the mechanisms underlying the effects of human umbilical cord mesenchymal stem cell (HUCMSC)-derived exosomes on M2 macrophage polarization in SLE-associated DAH via the microRNA (miR)-146a-5p/NOTCH1 axis. A DAH mouse model was established using pristane. Exosomes were isolated from HUCMSCs transfected or untransfected with the miR-146a-5p antagonist or agonist and their NCs and then injected into DAH mice. Additionally, miR-146a-5p was overexpressed in macrophages. Expression of miR-146a-5p, NOTCH1, M1 macrophage markers, and M2 macrophage markers was measured in mice and macrophages, and inflammatory factor levels were detected. Mouse lung injuries were evaluated, so was the binding of miR-146a-5p to NOTCH1. Rescue experiments were conducted in mice and macrophages using NOTCH1 shRNA and pcDNA3.1-NOTCH1, respectively. NOTCH1 expression was enhanced in DAH mice. HUCMSC-derived exosomes reduced NOTCH1 expression, bleeding, inflammation, and M1 macrophage polarization but elevated M2 macrophage polarization in lung tissues of DAH mice. Mechanistically, NOTCH1 is negatively targeted by miR-146a-5p. miR-146a-5p overexpression diminished M1 marker and inflammatory factor levels but enhanced M2 marker levels in macrophages, which was nullified by NOTCH1 overexpression. HUCMSC-derived exosomes with miR-146a-5p inhibition increased NOTCH1 expression, worsened bleeding and inflammation, and augmented M1 macrophage polarization while decreasing M2 macrophage polarization in lung tissues of DAH mice, which was abrogated by silencing NOTCH1. HUCMSC-derived exosomes diminished NOTCH1 expression to accelerate M2 macrophage polarization via delivery of miR-146a-5p, thus alleviating SLE-associated DAH in mice.