Lethal pulmonary thromboembolism in mice induced by intravenous human umbilical cord mesenchymal stem cell-derived large extracellular vesicles in a dose- and tissue factor-dependent manner.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have obvious advantages over MSC therapy. But the strong procoagulant properties of MSC-EVs pose a potential risk of thromboembolism, an issue that remains insufficiently explored. In this study, we systematically investigated the procoagulant activity of large EVs derived from human umbilical cord MSCs (UC-EVs) both in vitro and in vivo. UC-EVs were isolated from cell culture supernatants. Mice were injected with UC-EVs (0.125, 0.25, 0.5, 1, 2, 4 µg/g body weight) in 100 µL PBS via the tail vein. Behavior and mortality were monitored for 30 min after injection. We showed that these UC-EVs activated coagulation in a dose- and tissue factor-dependent manner. UC-EVs-induced coagulation in vitro could be inhibited by addition of tissue factor pathway inhibitor. Notably, intravenous administration of high doses of the UC-EVs (1 µg/g body weight or higher) led to rapid mortality due to multiple thrombus formations in lung tissue, platelets, and fibrinogen depletion, and prolonged prothrombin and activated partial thromboplastin times. Importantly, we demonstrated that pulmonary thromboembolism induced by the UC-EVs could be prevented by either reducing the infusion rate or by pre-injection of heparin, a known anticoagulant. In conclusion, this study elucidates the procoagulant characteristics and mechanisms of large UC-EVs, details the associated coagulation risk during intravenous delivery, sets a safe upper limit for intravenous dose, and offers effective strategies to prevent such mortal risks when high doses of large UC-EVs are needed for optimal therapeutic effects, with implications for the development and application of large UC-EV-based as well as other MSC-EV-based therapies.

Targeting Senescent Alveolar Epithelial Cells Using Engineered Mesenchymal Stem Cell-Derived Extracellular Vesicles To Treat Pulmonary Fibrosis.

Type 2 alveolar epithelial cell (AEC2) senescence is crucial to the pathogenesis of pulmonary fibrosis (PF). The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme cluster of differentiation 38 (CD38) is a marker of senescent cells and is highly expressed in AEC2s of patients with PF, thus rendering it a potential treatment target. Umbilical cord mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) have emerged as a cell-free treatment with clinical application prospects in antiaging and antifibrosis treatments. Herein, we constructed CD38 antigen receptor membrane-modified MSC-EVs (CD38-ARM-MSC-EVs) by transfecting MSCs with a lentivirus loaded with a CD38 antigen receptor-CD8 transmembrane fragment fusion plasmid to target AEC2s and alleviate PF. Compared with MSC-EVs, the CD38-ARM-MSC-EVs engineered in this study showed a higher expression of the CD38 antigen receptor and antifibrotic miRNAs and targeted senescent AEC2s cells highly expressing CD38 in vitro and in naturally aged mouse models after intraperitoneal administration. CD38-ARM-MSC-EVs effectively restored the NAD+ levels, reversed the epithelial-mesenchymal transition phenotype, and rejuvenated senescent A549 cells in vitro, thereby mitigating multiple age-associated phenotypes and alleviating PF in aged mice. Thus, this study provides a technology to engineer MSC-EVs and support our CD38-ARM-MSC-EVs to be developed as promising agents with high clinical potential against PF.

Procoagulant Properties of Mesenchymal Stem Cells and Extracellular Vesicles: A Novel Aspect of Thrombosis Pathogenesis.

Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into various cell types and secrete extracellular vesicles (EVs) that transport bioactive molecules and mediate intercellular communication. MSCs and MSC-derived EVs (MSC-EVs) have shown promising therapeutic effects in several diseases. However, their procoagulant activity and thrombogenic risk may limit their clinical safety. In this review, we summarize current knowledge on procoagulant molecules expressed on the surface of MSCs and MSC-EVs, such as tissue factor and phosphatidylserine. Moreover, we discuss how these molecules interact with the coagulation system and contribute to thrombus formation through different mechanisms. Additionally, various confounding factors, such as cell dose, tissue source, passage number, and culture conditions of MSCs and subpopulations of MSC-EVs, affect the expression of procoagulant molecules and procoagulant activity of MSCs and MSC-EVs. Therefore, herein, we summarize several strategies to reduce the surface procoagulant activity of MSCs and MSC-EVs, thereby aiming to improve their safety profile for clinical use.

Targeting cytohesin-1 suppresses acute myeloid leukemia progression and overcomes resistance to ABT-199.

Adhesion molecules play essential roles in the homeostatic regulation and malignant transformation of hematopoietic cells. The dysregulated expression of adhesion molecules in leukemic cells accelerates disease progression and the development of drug resistance. Thus, targeting adhesion molecules represents an attractive anti-leukemic therapeutic strategy. In this study, we investigated the prognostic role and functional significance of cytohesin-1 (CYTH1) in acute myeloid leukemia (AML). Analysis of AML patient data from the GEPIA and BloodSpot databases revealed that CYTH1 was significantly overexpressed in AML and independently correlated with prognosis. Functional assays using AML cell lines and an AML xenograft mouse model confirmed that CYTH1 depletion significantly inhibited the adhesion, migration, homing, and engraftment of leukemic cells, delaying disease progression and prolonging animal survival. The CYTH1 inhibitor SecinH3 exerted in vitro and in vivo anti-leukemic effects by disrupting leukemic adhesion and survival programs. In line with the CYTH1 knockdown results, targeting CYTH1 by SecinH3 suppressed integrin-associated adhesion signaling by reducing ITGB2 expression. SecinH3 treatment efficiently induced the apoptosis and inhibited the growth of a panel of AML cell lines (MOLM-13, MV4-11 and THP-1) with mixed-lineage leukemia gene rearrangement, partly by reducing the expression of the anti-apoptotic protein MCL1. Moreover, we showed that SecinH3 synergized with the BCL2-selective inhibitor ABT-199 (venetoclax) to inhibit the proliferation and promote the apoptosis of ABT-199-resistant leukemic cells. Taken together, our results not only shed light on the role of CYTH1 in cell-adhesion-mediated leukemogenesis but also propose a novel combination treatment strategy for AML.

Dynamic Changes of Blood Lipids in Breast Cancer Patients After (Neo)adjuvant Chemotherapy: A Retrospective Observational Study.

BACKGROUND: Previous studies indicated that the (neo)adjuvant chemotherapy for breast cancer can cause significant dyslipidemia in patients, but how long this abnormality can persist is unclear so far. The purpose of this study is to investigate whether (neo)adjuvant chemotherapy has a long-term effect on blood lipids in breast cancer patients. METHODS: A total of 159 newly diagnosed female breast cancer patients receiving the (neo)adjuvant chemotherapy subsequently and 159 female healthy controls were enrolled into the observational study. All participants' blood lipid profiles which included TC, TG, HDL-C, and LDL-C before and at the end of the 1st and 12th month after chemotherapy were retrieved from the electronic medical record system. The blood lipid profiles and the percentage of dyslipidemia before and after chemotherapy in breast cancer patients and controls were compared. RESULTS: Compared with the baseline before chemotherapy, TC, LDL-C, and TG increased significantly at the end of the 1st month after chemotherapy, but only the abnormal increase in TG (2.98±0.71 mmol/L vs 2.82±0.63 mmol/L, P<0.05) and LDL-C (1.82±0.42 mmol/L vs 1.59±0.42 mmol/L, P<0.05) continued until the 12th month after chemotherapy. Levels of HDL-C in breast cancer patients and all the blood lipid parameters in controls remained stable during the observation period. The percentage of dyslipidemia in breast cancer patients rose from 41.5% at baseline to 54.1% at the 12th month after chemotherapy. Subgroup analysis demonstrated that the increase in dyslipidemia percentage was more pronounced in patients with low body mass index and aged over 50 years. CONCLUSION: The (neo)adjuvant chemotherapy used for treating breast cancers can cause significant abnormalities in blood lipid profiles, and the abnormal increase in LDL-C and TG can last at least 12 months after chemotherapy, which indicates long-term management of blood lipid is necessary for those patients.

LncRNA MORT Inhibits Cancer Cell Proliferation and Promotes Apoptosis in Mantle Cell Lymphoma by Upregulating miRNA-16.

INTRODUCTION: LncRNA mortal obligate RNA transcript (MORT) is downregulated in different types of cancer, indicating its involvement in cancer biology. METHODS: In this study, MORT and miRNA-16 were both downregulated in plasma of mantle cell lymphoma (MCL) patients than that in the controls. The low levels of MORT and miRNA-16 were correlated with poor survival of MCL patients. The expression of MORT and miRNA-16 was positively correlated only in MCL patients. RESULTS: Overexpression of MORT and miRNA-16 suppressed cell proliferation but promoted cancer cell apoptosis, while miRNA-16 inhibitor reduced the effects of MORT overexpression. Overexpression of MORT led to upregulated expression of miRNA-16, while overexpression of miRNA-16 had no effect on the expression of MORT. CONCLUSION: Therefore, MORT may inhibit cancer cell proliferation and promote apoptosis in mantle cell lymphoma by upregulating miRNA-16.

Cardioprotective Effects and Duration of Beta Blocker Therapy in Anthracycline-Treated Patients: A Systematic Review and Meta-analysis.

Anthracycline-containing chemotherapy is commonly associated with irreversible cardiovascular toxicity. Beta blockers are currently recommended as first-line drugs for improving cardiac function. However, the effects of beta blocker on cardiac preservation and the duration of beta blocker intervention therapy in anthracycline-treated patients remain unclear. We systematically searched PubMed, Embase, and Cochrane for randomized controlled trials (published between January, 2000 and January, 2019) to determine the effectiveness of cardiac preservation of beta blocker in anthracycline-treated patients by accessing the change in left ventricular ejection fraction (LVEF) from pre- to post-chemotherapy. In addition, we conducted subgroup analysis based on the duration of beta blocker cardioprotective intervention and accumulative anthracycline dose. 11 RCTs were finally included. Beta blockers were associated with a significant smaller drop in the LVEF change (MD = 2.87, 95% CI 0.64 to 5.11, p = 0.01) compared to control groups. Besides, a subgroup analysis according to duration of beta blocker-based cardioprotective intervention (< 6 months vs = 6 months) showed significant subgroup difference in the LVEF change (MD = - 0.05, 95% CI - 0.91 to 0.81, p = 0.91; MD = 6.48, 95% CI 2.44 to 10.52, p = 0.002). An additional subgroup analysis according to accumulative anthracycline dose showed statistically significant difference in the LVEF change (MD = 4.61, 95% CI 0.78 to 8.45, p = 0.02) with moderate accumulative dose of anthracycline (doxorubicin between 250 and 400 mg/m2). Prophylactic administration of beta blocker-based cardioprotective therapy may be beneficial to the myocardial preservation in anthracycline-treated patients. And long-term use of beta blocker appears to have a positive effect on ameliorating anthracycline-induced cardiomyopathy, especially in patients exposed to moderate accumulative doses of anthracycline.