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.

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.

Illness uncertainty, self-perceived burden and quality of life in patients with chronic myeloid leukaemia: A cross-sectional study.

AIMS AND OBJECTIVES: To investigate the relationship between illness uncertainty, self-perceived burden and quality of life and explore the mediating role of self-perceived burden between illness uncertainty and quality of life in patients with chronic myeloid leukaemia. BACKGROUND: Patients with chronic myeloid leukaemia need long-term, potentially lifelong therapy to control the disease, which affects their quality of life. There is a need for exploring potentially changeable factors to develop interventions. Little is known about the effects of illness uncertainty and self-perceived burden on quality of life in this population. DESIGN: A cross-sectional study. METHODS: A convenience sample of 248 patients with chronic myeloid leukaemia was recruited from four university hospitals from February to August 2020. Participants were assessed with the Mishel Uncertainty in Illness Scale, Self-Perceived Burden Scale, and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire. The STROBE checklist was used to report the results. RESULTS: Illness uncertainty and self-perceived burden were negatively associated with quality of life in patients with chronic myeloid leukaemia. Self-perceived burden partially mediated the relationship between illness uncertainty and quality of life. The indirect effect was -0.101, accounting for 22.9% of the total effect. CONCLUSION: The findings revealed the relationship between illness uncertainty, self-perceived burden and quality of life in patients with chronic myeloid leukaemia. Self-perceived burden exerted a mediating role between illness uncertainty and quality of life in this population. RELEVANCE TO CLINICAL PRACTICE: This study alerts healthcare providers to pay attention to patients' illness uncertainty and self-perceived burden, which can contribute to develop effective interventions to improve the quality of life among patients with chronic myeloid leukaemia in the clinical practice.