Myelodysplastic syndromes

The Mechanism of miR-155/miR-15b Axis Contributed to Apoptosis of CD34+ Cells by Upregulation of PD-L1 in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal diseases that are characterized by ineffective bone marrow hematopoiesis. Since studies have confirmed the significance of miRNAs in ineffective hematopoiesis in MDS, the current report elucidated the mechanism mediated by miR-155-5p. The bone marrow of MDS patients was collected to detect miR-155-5p and to analyze the correlation between miR-155-5p and clinicopathological variables. Isolated bone marrow CD34+ cells were transfected with lentiviral plasmids that interfere with miR-155-5p, followed by apoptosis analysis. Finally, miR-155-5p-targeted regulation of RAC1 expression was identified, as well as the interaction between RAC1 and CREB, the co-localization of RAC1 and CREB, and the binding of CREB to miR-15b. As measured, miR-155-5p was upregulated in the bone marrow of MDS patients. Further cell experiments validated that miR-155-5p promoted CD34+ cell apoptosis. miR-155-5p could reduce the transcriptional activity of miR-15b by inhibiting RAC1, dissociating the interaction between RAC1 and CREB, and inhibiting the activation of CREB. Upregulating RAC1, CREB, or miR-15b could reduce miR-155-5p-mediated apoptosis promotion on CD34+ cells. Additionally, miR-155-5p could force PD-L1 expression, and this effect was impaired by elevating RAC1, CREB, or miR-15b. In conclusion, miR-155-5p mediates PD-L1-mediated apoptosis of CD34+ cells in MDS by RAC1/CREB/miR-15b axis, thereby inhibiting bone marrow hematopoiesis.

miR-34a induces neutrophil apoptosis by regulating Cdc42-WASP-Arp2/3 pathway-mediated F-actin remodeling and ROS production

Background

The number of neutrophils is significantly reduced in myelodysplastic syndrome (MDS), but the molecular basis remains unclear. We recently found that miR-34a was significantly increased in MDS neutrophils. Therefore, this study aims to clarify the effects of aberrant miR-34a expression on neutrophil counts.

Methods

miR-34a mimics/inhibitor transfection were performed in neutrophil-like differentiated HL60 (dHL60) cells, and a FACSCalibur flow cytometer was used to measure ROS production and apoptosis. In addition, the Cdc42-WASP-Arp2/3 pathway inhibitor (ML141) and activator (CN02) treated the dHL60 cells, and then ROS production, apoptosis and related proteins expression were detected. And, luciferase reporter assay to verify the relationship of miR-34a and the Cdc42-WASP-Arp2/3 pathway.

Results

overexpression of miR-34a could induce ROS production and apoptosis, decrease the expression levels of DOCK8, p-WASP, WASP, Arp2, Arp3, and increase F-actin’s expression. Meanwhile, knockdown of miR-34a could decrease ROS production and apoptosis, increase the expression of DOCK8, p-WASP, WASP, Arp2, Arp3, and decrease F-actin’s expression. Immunofluorescence staining showed aberrant miR-34a and Cdc42-WASP-Arp2/3 pathway could induce F-actin membrane transfer. Luciferase reporter assay indicated that DOCK8 was a direct target gene of miR-34a.

Conclusion

These data indicates miR-34a may induce neutrophil apoptosis by regulating Cdc42-WASP-Arp2/3 pathway-mediated F-actin remodeling and ROS production.

Global Proteomics Analysis of Bone Marrow: Establishing Talin-1 and Centrosomal Protein of 55 kDa as Potential Molecular Signatures for Myelodysplastic Syndromes

Myelodysplastic syndrome (MDS) is a hematological disorder characterized by abnormal stem cell differentiation and a high risk of acute myeloid leukemia transformation. Treatment options for MDS are still limited, making the identification of molecular signatures for MDS progression a vital task. Thus, we evaluated the proteome of bone marrow plasma from patients (n = 28) diagnosed with MDS with ring sideroblasts (MDS-RS) and MDS with blasts in the bone marrow (MDS-EB) using label-free mass spectrometry. This strategy allowed the identification of 1,194 proteins in the bone marrow plasma samples. Polyubiquitin-C (UBC), moesin (MSN), and Talin-1 (TLN1) showed the highest abundances in MDS-EB, and centrosomal protein of 55 kDa (CEP55) showed the highest relative abundance in the bone marrow plasma of MDS-RS patients. In a follow-up, in the second phase of the study, expressions of UBC, MSN, TLN1, and CEP55 genes were evaluated in bone marrow mononuclear cells from 45 patients by using qPCR. This second cohort included only seven patients from the first study. CEP55, MSN, and UBC expressions were similar in mononuclear cells from MDS-RS and MDS-EB individuals. However, TLN1 gene expression was greater in mononuclear cells from MDS-RS (p = 0.049) as compared to MDS-EB patients. Irrespective of the MDS subtype, CEP55 expression was higher (p = 0.045) in MDS patients with abnormal karyotypes, while MSN, UBC, and TALIN1 transcripts were similar in MDS with normal vs. abnormal karyotypes. In conclusion, proteomic and gene expression approaches brought evidence of altered TLN1 and CEP55 expressions in cellular and non-cellular bone marrow compartments of patients with low-risk (MDS-RS) and high-risk (MDS-EB) MDSs and with normal vs. abnormal karyotypes. As MDS is characterized by disrupted apoptosis and chromosomal alterations, leading to mitotic slippage, TLN1 and CEP55 represent potential markers for MDS prognosis and/or targeted therapy.

CD177 Enhances the Detection of Myelodysplastic Syndrome by Flow Cytometry

OBJECTIVES

Previously we demonstrated that a decreased percentage of CD177-positive granulocytes detected by flow cytometry (FCM) was associated with myelodysplastic syndrome (MDS). Here we expand on those findings to more rigorously evaluate the utility of CD177 for the detection of MDS.

METHODS

Two hundred patient samples (100 MDS and 100 controls) were evaluated for granulocyte expression of CD177 and 11 other flow cytometric parameters known to be associated with MDS.

RESULTS

We show that CD177, as a single analyte, is highly correlated with MDS with a receiver operating characteristic area under curve value of 0.8. CD177 expression below 30% demonstrated a sensitivity of 51% and a specificity of 94% for detecting MDS with a positive predictive value of 89.5%. In multivariate analysis of 12 MDS-associated FCM metrics, CD177 and the Ogata parameters were significant indicators of MDS, and CD177 increased sensitivity of the Ogata score by 16% (63%-79%) for predicting MDS. Finally, diagnostic criteria incorporating these parameters with a 1% blast cutoff level and CD177 resulted in a sensitivity of 90% and specificity of 91% for detecting MDS.

CONCLUSIONS

The findings indicate CD177 is a useful FCM marker for MDS.

Gene mutational analysis by NGS and its clinical significance in patients with myelodysplastic syndrome and acute myeloid leukemia

Background

In this study, we retrospectively summarized the differences of molecular gene mutations between MDS and AML patients, as well as the young and older age groups of MDS and AML patients. We also analyzed the response of newly diagnosed AML patients to standard DA or IA induction chemotherapy and the relationship between the chemotherapy outcome and the frequency of different gene mutation abnormalities.

Methods

NGS assay covering 43 genes was studied in 93 de novo MDS and 325 non-M3 AML patients. Bone marrow samples from all patients underwent gene mutational analysis by NGS.

Results

At least one non-synonymous gene mutation was detected in 279 AML patients (85.8%) and 85 MDS patients (91.4%). Contrary to 59 years and younger AML patients, there was a significantly higher incidence of gene mutation in 60 years and older AML patients (2.37 vs 1.94, p = 0.034). Gene mutation incidence in 60 years and older MDS patients increased, but no statistical significance was present (1.95 vs 1.64, p = 0.216). AML patients had a significantly higher gene mutation incidence compared with MDS-MLD patients (2.02 vs 1.63, p = 0.046). Gene mutation incidence was higher in patients with MDS-EB1/EB2 compared with patients with MDS-MLD but there was no statistical significance present (2.14 vs 1.63, p = 0.081). AML patients had significantly higher incidences of CEBPA, FLT3-ITD, DNMT3A, NPM1 and IDH1/2 gene mutations (p = 0.0043, 0.000, 0.030962, 0.002752, and 0.000628, respectively) and a lower incidence of TET2 and U2AF1 gene mutations (p = 0.000004 and 0.000, respectively) compared with MDS patients. Among the individual genes in different age groups, there were significantly higher incidences of RUNX1, IDH2, TP53 and SF3B1 gene mutations (p = 0.0478, 0.0028, 0.0024 and 0.005, respectively) as well as a trend of higher ASXL gene mutation (p = 0.057) in 60 years and older AML patients compared to 59 years and younger patients. There was no statistically significant difference in MDS patients with the different age groups and among the individual genes. Between AML patients and MDS patients among the different gene functional groups, AML patients had a significantly higher incidence of transcriptional deregulation (27.4% vs 15.1%, p = 0.014963), activated signalling (36.3% vs 10.8%, p = 0.000002) related gene mutations as well as a significantly lower incidence of RNA spliceosome (6.15% vs 60.1%, p = 0.000) related gene mutations. Furthermore, among the patients who received either IA or DA regimen for induction chemotherapy, patients with IA regimen had a significantly better CR rate than those with DA regimen (76.6% vs 57.1%, p = 0.0228).

Conclusions

Different gene mutations had been found in majority of MDS and AML patients. MDS and AML patients had different gene mutation patterns. AML patients with fewer or no gene mutations had a better chance of achieving CR when treated with IA and DA regimen induction chemotherapy.

The Use of Flow Cytometry in Myelodysplastic Syndromes: A Review

Myelodysplastic syndromes (MDSs) are a heterogeneous group of hematopoietic stem cell diseases categorized by dysplasia in one or more hematopoietic cell lineages, as well as cytopenia and functional abnormalities in bone marrow cells. Several MDS classification methods have been proposed to categorize the disease and help professionals better plan in patients’ treatment. The World Health Organization classification, released in 2008 and revised in 2016, is the currently and the most used classification method worldwide. Recent advances in MDS molecular biology and innovations in flow cytometry have enabled the development of new parameters for MDS diagnosis and classification. Several groups have published flow cytometry scores and guidelines useful for the diagnosis and/or prognosis of MDS, which are mostly based on detecting immunophenotypic abnormalities in granulocyte, monocyte, and lymphoid lineages. Here, we review the current literature and discuss the main parameters that should be analyzed by flow cytometry with the aim of refining MDS diagnosis and prognosis. Furthermore, we discuss the critical role of flow cytometry and molecular biology in MDS diagnosis and prognosis, as well as the current challenges and future perspectives involving these techniques.

Bone Marrow Immunity and Myelodysplasia

Myelodysplastic syndrome (MDS) is characterized by an ineffective hematopoiesis with production of aberrant clones and a high cell apoptosis rate in bone marrow (BM). Macrophages are in charge of phagocytosis. Innate Immune cells and specific T cells are in charge of immunosurveillance. Little is known on BM cell recruitment and activity as BM aspirate is frequently contaminated with peripheral blood. But evidences suggest an active role of immune cells in protection against MDS and secondary leukemia. BM CD8⁺ CD28⁻ CD57⁺ T cells are directly cytotoxic and have a distinct cytokine signature in MDS, producing TNF-α, IL-6, CCL3, CCL4, IL-1RA, TNFα, FAS-L, TRAIL, and so on. These tools promote apoptosis of aberrant cells. On the other hand, they also increase MDS-related cytopenia and myelofibrosis together with TGFβ. IL-32 produced by stromal cells amplifies NK cytotoxicity but also the vicious circle of TNFα production. Myeloid-derived suppressing cells (MDSC) are increased in MDS and have ambiguous role in protection/progression of the diseases. CD33 is expressed on hematopoietic stem cells on MDS and might be a potential target for biotherapy. MDS also has impact on immunity and can favor chronic inflammation and emergence of autoimmune disorders. BM is the site of hematopoiesis and thus contains a complex population of cells at different stages of differentiation from stem cells and early engaged precursors up to almost mature cells of each lineage including erythrocytes, megakaryocytes, myelo-monocytic cells (monocyte/macrophage and granulocytes), NK cells, and B cells. Monocytes and B cell finalize their maturation in peripheral tissues or lymph nodes after migration through the blood. On the other hand, T cells develop in thymus and are present in BM only as mature cells, just like other well vascularized tissues. BM precursors have a strong proliferative capacity, which is usually associated with a high risk for genetic errors, cell dysfunction, and consequent cell death. Abnormal cells are prone to destruction through spontaneous apoptosis or because of the immunosurveillance that needs to stay highly vigilant. High rates of proliferation or differentiation failures lead to a high rate of cell death and massive release of debris to be captured and destroyed (1). Numerous macrophages reside in BM in charge of home-keeping. They have a high capacity of phagocytosis required for clearing all these debris.

Importance of classical morphology in the diagnosis of myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders characterized by dysplastic, ineffective, clonal and neoplastic hematopoiesis. MDS represent a complex hematological problem: differences in disease presentation, progression and outcome have necessitated the use of classification systems to improve diagnosis, prognostication, and treatment selection. However, since a single biological or genetic reliable diagnostic marker has not yet been discovered for MDS, quantitative and qualitative dysplastic morphological alterations of bone marrow precursors and peripheral blood cells are still fundamental for diagnostic classification. In this paper, World Health Organization (WHO) classification refinements and current minimal diagnostic criteria proposed by expert panels are highlighted, and related problematic issues are discussed. The recommendations should facilitate diagnostic and prognostic evaluations in MDS and selection of patients for new effective targeted therapies. Although, in the future, morphology should be supplemented with new molecular techniques, the morphological approach, at least for the moment, is still the cornerstone for the diagnosis and classification of these disorders.

A primary care approach to myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are probably the most common hematologic malignancies in adults over the age of 60 and are a major source of morbidity and mortality among older age groups. Diagnosis and management of this chronic blood cancer has evolved significantly in recent years and there are Food and Drug Administration-approved therapies that can extend patients' life expectancy and improve quality of life. Primary care physicians (PCPs) are often involved in the process of diagnosis and follow-up of MDS patients, especially those in low-risk groups. They can therefore play an important role in improving patient care and quality of life by ensuring early referral and participating in supportive management. There is also a shortage of oncologists which increases the importance of the role of PCPs in management of MDS patients. In the face of limited resources, PCPs can improve access and quality of care in MDS patients. This article provides an overview of the common manifestations, diagnostic approaches, and therapeutic modalities of MDS for PCPs, with a focus on when to suspect MDS, when a referral is appropriate, and how to provide appropriate supportive care for patients diagnosed with MDS.

Histopathological and immunohistochemical evaluation of bone marrow biopsy in myelodysplastic syndromes

SUMMARY In myelodysplastic syndromes (MDS), bone marrow biopsy (BMB) is now considered part of a multidisciplinary approach to bone marrow (BM) examination that must include cytological and cytogenetic assessment, while flow-cytometry and molecular studies can provide additional useful information. Undervalued in the past, BM histology has recently grown in importance in terms of diagnosis (i.e., MDS with BM fibrosis, hypoplastic MDS) and prognostic assessment (i.e., clusters of CD34+ blasts). Thus, BM histology must be considered complementary and not overlapping with the results of the other methods of BM study. Moreover, in recent years, numerous clinico-pathological studies have evidentiated, codified and standardized a series of histopathological parameters that are now considered essential for an effective and clinically useful histomorphological evaluation of the BMB. The aim of this work is to describe the histopathological and immunohistochemical approach to BMB that the pathologists of the Lombard Hematological Network (Rete Ematologica Lombarda [REL]; Italy) are carrying out on a standardized and shared basis in MDS patients.

Risks for infection in patients with myelodysplasia and acute leukemia

PURPOSE OF REVIEW

The aim of the present review is to analyze the main parameters that may influence the onset of bacterial, fungal and viral infections in patients with myelodysplastic syndromes, acute myeloid leukemia and acute lymphoid leukemia.

RECENT FINDINGS

The identification of factors influencing the onset of infections in high-risk patients is becoming one of the most important strategies to identify those patients who would really benefit from prophylactic and timely treatment. During the past few years several studies have been conducted to evaluate the impact of risk factors that may influence both the onset and the outcome of infections. The role of some of them is well defined (i.e. neutropenia, central venous catheters), whereas other factors are now emerging as new possible causative factors (i.e. iron overload, hospitalization).

SUMMARY

Many factors have to be considered when evaluating the infectious risk in hematological patients. In current clinical practice the good knowledge of these factors may favor a better management of infectious risk, with a reduction of mortality rate.