CMV infection is a risk factor for hemorrhagic cystitis after hematopoietic stem cell transplantation.

Hemorrhagic cystitis (HC) is a common complication after transplantation. The purpose of this study was to examine the incidence and risk factors for HC after hematopoietic stem cell transplantation (HSCT). The records of patients who underwent allogenic HSCT from January 2012 to December 2018 at our institution were retrospectively reviewed. Cox proportional regression and Kaplan-Meier analyses were performed to determine independent risk factors for HC. The statistical analysis was performed in May 2020. A total of 173 patients underwent HSCT, and 53 (30.6%) developed grade 2 or 3 HC cystitis at a median of 37 days (range - 5 to 98 days) after transplantation. Thirty-two patients developed moderate (grade 2) cystitis and 21 severe (grade 3) cystitis. Of the 173 patients, 61 developed acute graft-versus-host disease (GVHD) (median onset day 24) and 79 experienced cytomegalovirus (CMV) reactivation (median onset day 35). The relative risk (RR) of developing a CMV infection for patients with acute GVHD was 2.77 times that of patients without acute GVHD (P < 0.001). CMV infection was the only independent variable significantly associated with HC in both univariate and multivariate analyses. The estimated hazard ratio (HR) of CMV infection for the development of HC was 5.57 (95% confidence interval [CI]: 2.52 to 12.33, P < 0.001). CMV infection is an independent risk factor for the development of HC after HSCT, and acute GVHD is a risk factor for CMV reactivation. Decreasing the frequency of GVHD after HSCT may result in a lower frequency of HC.

HDAC8 promotes daunorubicin resistance of human acute myeloid leukemia cells via regulation of IL-6 and IL-8.

The chemoresistance is one of the major challenges for acute myeloid leukemia (AML) treatment. We found that the expression of histone deacetylase 8 (HDAC8) was increased in daunorubicin (DNR) resistant AML cells, while targeted inhibition of HDAC8 by its specific siRNA or inhibitor can restore sensitivity of DNR treatment . Further, targeted inhibition of HDAC8 can suppress expression of interleukin 6 (IL-6) and IL-8. While recombinant IL-6 (rIL-6) and rIL-8 can reverse si-HDAC8-resored DNR sensitivity of AML cells. Mechanistical study revealed that HDAC8 increased the expression of p65, one of key components of NF-κB complex, to promote the expression of IL-6 and IL-8. It might be due to that HDAC8 can directly bind with the promoter of p65 to increase its transcription and expression. Collectively, our data suggested that HDAC8 promotes DNR resistance of human AML cells via regulation of IL-6 and IL-8.

A Case of Granulocytic Sarcoma of the Lung in Acute Myeloid Leukemia.

BACKGROUND: Granulocytic sarcoma in the lung is a rare presentation of acute myeloid leukemia (AML). Here, we describe a rare case of granulocytic sarcoma of the lung in a 56-year-old male patient with AML. METHODS: Hematologic investigation, bone marrow aspirate, cytogenetic analysis, chest computed tomography (CT), and pulmonary biopsy were performed. RESULTS: The patient achieved complete remission (CR) after induction therapy, but the patient refused further treatment and was lost to follow-up. CONCLUSIONS: Pulmonary biopsy and bone marrow aspirate are important to confirm a correct diagnosis. Pulmo-nary granulocytic sarcoma as a prognostic factor needs further studies.

A Case of Renal Involvement in B Lymphoblastic Lymphoma Leukemia.

BACKGROUND: Renal involvement is rare in B lymphoblastic lymphoma (B-LBL). The authors describe a rare case of renal involvement in a 21-year-old male patient with B lymphoblastic lymphoma leukemia, presenting with severe lactic acidosis. METHODS: Hematologic investigation, bone marrow aspirate and biopsy, cytogenetic analysis and renal biopsy were performed. RESULTS: The patient achieved complete hematological remission (CHR) after induction therapy with the regimen of VDCP and received consolidation chemotherapy regularly. He remained CHR until now. CONCLUSIONS: Renal biopsy, bone marrow aspirate, and biopsy are important to confirm a correct diagnosis. Renal involvement in B-LBL as a prognostic factor needs further studies.

Vitamin C promotes anti-leukemia of DZNep in acute myeloid leukemia.

The epigenetic treatment by 3-Deazaneplanocin A (DZNep), a histone methyltransferase inhibitor, shows great potential against acute myeloid leukemia (AML). However, the variant sensitivity and incomplete response to DZNep are commonly observed. Here, we reveal that vitamin C (Vc) dramatically promotes DZNep response against leukemic cells in different cell lines and primary AML samples. Vc enhances apoptosis and differentiation induced by DZNep in different AML cell lines in vitro and reduces leukemia progression in vivo. At the molecular level, Vc downregulates an enzyme of serine synthesis named D-3-phosphoglycerate dehydrogenase (PHGDH), as well as BCL2, an anti-apoptotic gene. Over-expression of PHGDH reverses the Vc-enhanced anti-leukemic effect of DZNep in AML cells. Therefore, our findings provide an effective approach to reduce the resistance against epigenetic treatment by Vc, which shows a potential improvement of their combination in AML patients.

Bone Marrow Mesenchymal Stem Cells-Derived Exosomal miR-425-5p Inhibits Acute Myeloid Leukemia Cell Proliferation, Apoptosis, Invasion and Migration by Targeting WTAP.

INTRODUCTION: Acute myeloid leukemia (AML) is a predominant blood malignancy with high mortality and severe morbidity. AML is affected by microRNAs (miRNAs) loaded in exosomes derived from bone marrow mesenchymal stem cells (BM-MSCs). MiR-425-5p has been reported to participate in different cancer models. However, the function of BM-MSCs-derived exosomal miR-425-5p in AML is unclear. METHODS: The expression of miR-425-5p was measured by qRT-PCR in clinical AML samples. The immunophenotype of BM-MSCs was analyzed using antibodies against CD44, CD90, and CD105. The exosome was isolated from BM-MSCs. The effect of BM-MSCs-derived exosomal miR-425-5p on AML was analyzed by CCK-8 assay, Edu assay, transwell assay, flow cytometry in AML cells. qRT-PCR, luciferase reporter gene assay and Western blot analysis were also conducted in AML cells. RESULTS: The expression levels of miR-425-5p were decreased in CD34 + CD38-AML cells from primary AML patients compared to that from the bone marrow of healthy cases, and were reduced in exosomes from AML patients compared that from healthy cases. Similarly, miR-425-5p was also down-regulated in AML cell lines compared with BM-MSCs. MiR-425-5p was able to express in exosomes from BM-MSCs. CCK-8, Edu, transwell assay and flow cytometry analysis revealed that BM-MSCs-derived exosomal miR-425-5p significantly inhibited cell viability, Edu positive cells, invasion and migration, and induced apoptosis of AML cells. Meanwhile, the expression levels of cleaved PARP and cleaved caspase3 were increased by BM-MSCs-derived exosomal miR-425-5p in cells. MiR-425-5p inhibited the expression of Wilms tumor 1-associated protein (WTAP). Moreover, overexpression of WTAP could reverse the miR-425-5p-induced inhibition effect on AML cell proliferation, apoptosis, migration and invasion. CONCLUSION: BM-MSCs-derived exosomal miR-425-5p inhibits proliferation, invasion and migration of AML cells and induced apoptosis of AML cells by targeting WTAP. Therapeutically, BM-MSCs-derived exosomal miR-425-5p may serve as a potential target for AML therapy.

A Regulatory Loop Involving Notch and Wnt Signaling Maintains Leukemia Stem Cells in T-Cell Acute Lymphoblastic Leukemia.

Leukemia-initiating cells play critical role in relapse, resistance to therapies and metastases but the mechanism remains largely elusive. We report that ß-catenin is over-expressed in almost all T-ALL patients and flow sorted ß-cateninhigh fractions are highly resistant to therapy, leading to liver metastases in nude mice as well as dysregulated lncRNAs. Pharmacological inhibition through XAV-939 as well as si-RNA mediated inhibition of ß-catenin is initially effective in re-sensitization to therapy, however, prolonged inhibition shifts dependency from ß-catenin to Notch signaling, with particularly high levels of receptors Notch 1 and Notch 2. The results are verifiable in a cohort of T-ALL patients comprising of responders vs. those who have progressed, with ß-catenin, Notch 1 and Notch 2 elevated in progressed patients. Further, in patients-derived cells, silencing of Notch 1 or Notch 2 does not counter resistance to ß-catenin inhibition, rather pharmacological pan-Notch inhibition is needed to overcome resistance and its effect on in vitro tumor sphere formations as well as in vivo liver metastases. Thus, wnt and Notch signaling are part of a regulatory loop mutually compensating for each other in T-ALL, while ensuring the maintenance of stem cell phenotype.

Generation of a RGS18 gene knockout cell line from a human embryonic stem cell line by CRISPR/Cas9.

RGS18 is a member of the RGS (Regulators of G-protein signaling) protein family, involved in megakaryopoiesis, megakaryocyte differentiation and chemotaxis. Here, we created a RGS18 knockout cell line from a human embryonic stem cell line by CRISPR/Cas9 mediated gene targeting, to further understand roles of RGS18 in these processes. The cell line maintains stem cell morphology and normal karyotype, and retains expression of pluripotent marker genes and differentiation potential in vivo. The RGS18-/- cell line will facilitate investigation of the role of RGS18 during multiple cellular processes in human pluripotent stem cell modeled hematopoiesis.

Characterization and generation of human definitive multipotent hematopoietic stem/progenitor cells.

Definitive hematopoiesis generates hematopoietic stem/progenitor cells (HSPCs) that give rise to all mature blood and immune cells, but remains poorly defined in human. Here, we resolve human hematopoietic populations at the earliest hematopoiesis stage by single-cell RNA-seq. We characterize the distinct molecular profiling between early primitive and definitive hematopoiesis in both human embryonic stem cell (hESC) differentiation and early embryonic development. We identify CD44 to specifically discriminate definitive hematopoiesis and generate definitive HSPCs from hESCs. The multipotency of hESCs-derived HSPCs for various blood and immune cells is validated by single-cell clonal assay. Strikingly, these hESCs-derived HSPCs give rise to blood and lymphoid lineages in vivo. Lastly, we characterize gene-expression dynamics in definitive and primitive hematopoiesis and reveal an unreported role of ROCK-inhibition in enhancing human definitive hematopoiesis. Our study provides a prospect for understanding human early hematopoiesis and a firm basis for generating blood and immune cells for clinical purposes.

CircRNA circ_0000190 inhibits the progression of multiple myeloma through modulating miR-767-5p/MAPK4 pathway.

BACKGROUND: Multiple myeloma (MM) accounts for 10% of all hematological malignancies. Dysregulation of microRNAs (miRNAs) or long non-coding RNAs (lncRNAs) has important impacts on progression of MM. Circular RNAs (circRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of circ_0000190 on regulating the progression of MM. METHOD: Microscopic examination via single molecule fluorescent in situ hybridization indicates the location of circ_0000190. qRT-PCR and Western blot were used to evaluate the expression of RNAs and proteins. Potential target of circ_0000190 was searched as miRNA, and examined by luciferase reporter assay. A computational screen was also conducted to search the potential target of miRNA. In vitro cell viability, proliferation, apoptosis assays and flow cytometric were performed to assess the effects of circ_0000190 and its target on MM. Mice model of human MM was established with subcutaneous xenograft tumor, qRT-PCR and western blot were performed to detect the underlying mechanisms of circ_0000190 on MM. RESULTS: Circ_0000190 was located in the cytoplasm, and down-regulated in both bone marrow tissue and peripheral blood, while the target of circ_0000190, miR-767-5p, was up-regulated, suggesting a negative correlation between them. The binding ability between circ_0000190 and miR-767-5p was confirmed by luciferase reporter assay. Moreover, circ_0000190 inhibited cell viability, proliferation and induced apoptosis of MM thus inhibiting cell progression, which is partially through the negative regulation of miR-767-5p. Mitogen-activated protein kinase 4 (MAPK4) is a direct target of miR-767-5p. In addition, over-expression of miR-767-5p promoted cell progression by directly targeting and regulating MAPK4. The MM model mice with administration of circ_0000190 suppressed tumor growth and progression. CONCLUSION: Our results revealed that the ability of circ_0000190 to protect against MM was inherited through repression of miR-767-5p, and miR-767-5p might be a tumor drive through targeting MAPK4. Therefore, a novel role of circ_0000190 on regulating the progression of MM was found, and the clinical application of circRNAs might represent a strategy in MM.