Pathogenesis Of Myelodysplastic Syndromes Research Articles

VERY COMPLEX KARYOTYPE IN YOUNG MYELODYSPLASTIC SYNDROME PATIENT AFTER CHRONIC EXPOSURE TO CHLOROFORM

Myelodysplastic Syndrome (MDS) is marked by biological and clinical heterogeneity, characterized by dysplasia in the bone marrow and blood cells with the presence of cytopenias. MDS is recognized as a disease in elderly individuals. About 86% of MDS cases are diagnosed at age ≥ 60 and less than 10% of patients are younger than 50. Recurrent cytogenetic abnormalities are present in 40% to 60% of cases. Cytogenetic analysis plays an important role, whether in the diagnosis or classification of the disease. Recently, the new international molecular prognostic score system (IPSS-M) reinforces the valuable prognostic contribution of cytogenetics in MDS in both survival and leukemic evolution. To report a chronic chloroform exposure as a trigger capable of inducing DNA damage. Chronic exposure to a genotoxic agent has been linked to MDS chromosomal abnormality. Among these, chloroform, and an inorganic halide derivative of hydrocarbons can induce the DNA lesion. A 24-year-old male patient with a marked history of 10-year chloroform exposure sought medical attention for anemia, fainting, and unintentional weight loss. He was diagnosed with Myelodysplastic Syndrome and refractory anemia with excess blasts (RAEB II) with initial tests: Hb = 5 g/dL; neutrophils=320/mm3; platelets= 18 x 109/L. Bone marrow aspiration showed 15% myeloblasts, immunohistochemistry profile showed CD34+, CD117+ in blasts and cytogenetic analysis showed a very complex karyotype: 45,XY,del(6)(q22),-7,add(9) (q12),del(12)(p11.2),del(17)(p13),del(20)(q12),add(21(p13)[17]/46, XY[3]. Chemotherapy with azacitidine was performed as a bridge to bone marrow transplantation, but the patient evolved into sepsis, dying eight months after diagnosis. The pathogenesis of MDS reflects the heterogeneity of the disease, thus, comprises multiple steps and includes factors that can be endogenous and/or exogenous. Therefore, this unusual case shows the extreme importance of investigating possible recurrent and/or occupational exposures in these patients combined with cytogenetics analyses.

INCREASED PROGRAMMED DEATH LIGAND-1 EXPRESSION LEADS TO WORSE CLINICAL FEATURES IN PATIENTS WITH MYELODYSPLASTIC SYNDROME

Immune checkpoints are regulators of the immune system response that allow self-tolerance. Molecules such as Programmed Cell Death Protein 1 (PD-1) and its Ligand (PD-L1) participate in the immune checkpoint by signaling co-inhibition of lymphocyte responses. In cancers, PD-L1 expression is associated with the immune evasion mechanism, which favors tumor growth. The role of PD-L1 is already known for several solid tumors and anti-PD-L1 drugs are used for treatment. Myelodysplastic Syndrome (MDS) is a heterogeneous bone marrow disease with an increased risk of progression to Acute Myeloid Leukemia (AML). The pathogenesis of MDS involves several factors, including alterations in immune pathways. However, the role of PD-L1 still lacks understanding in this disease. The aim of this study was to evaluate if PD-L1 gene expression would be linked to clinical and prognostic features in patients with myelodysplastic syndrome. In this study, we evaluated PD-L1 mRNA expression by real-time PCR using TaqMan ® probes. Fifty-three patients classified according to WHO 2016 were analyzed. We observed that patients with dyserythropoiesis have higher PD-L1 expression than patients without dyserythropoiesis (p = 0.050). Furthermore, patients classified as excess of blasts 2 (MDS-EB2) presented an upregulation in mRNA expression of PD-L1 compared to excess of blasts 1 (MDS-EB1) (p = 0.050). Throughout the statistical analysis, we detected three patients with very high levels of PD-L1 expression, being classified as outliers. Analyzing these three patients specifically, all of them had hemoglobin lower than 8g/dL, blast count higher than 8%, dysplasia in at least two sectors and had died by the end of the study. The increase of PD-L1 in MDS may be considered a marker of poor prognosis.

The yin-yang of immunity: Immune dysregulation in myelodysplastic syndrome with different risk stratification.

Myelodysplastic syndrome (MDS) is a heterogeneous group of myeloid clonal diseases with diverse clinical courses, and immune dysregulation plays an important role in the pathogenesis of MDS. However, immune dysregulation is complex and heterogeneous in the development of MDS. Lower-risk MDS (LR-MDS) is mainly characterized by immune hyperfunction and increased apoptosis, and the immunosuppressive therapy shows a good response. Instead, higher-risk MDS (HR-MDS) is characterized by immune suppression and immune escape, and the immune activation therapy may improve the survival of HR-MDS. Furthermore, the immune dysregulation of some MDS changes dynamically which is characterized by the coexistence and mutual transformation of immune hyperfunction and immune suppression. Taken together, the authors think that the immune dysregulation in MDS with different risk stratification can be summarized by an advanced philosophical thought “Yin-Yang theory” in ancient China, meaning that the opposing forces may actually be interdependent and interconvertible. Clarifying the mechanism of immune dysregulation in MDS with different risk stratification can provide the new basis for diagnosis and clinical treatment. This review focuses on the manifestations and roles of immune dysregulation in the different risk MDS, and summarizes the latest progress of immunotherapy in MDS.

A research review of experimental animal models with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) consists of a group of hematologic tumors that are derived from the clonal proliferation of hematopoietic stem cells, featuring abnormal hematopoietic cell development and ineffective hematopoiesis. Animal models are an important scientific research platform that has been widely applied in the research of human diseases, especially tumors. Animal models with MDS can simulate characteristic human genetic variations and tumor phenotypes. They also provide a reliable platform for the exploration of the pathogenesis and diagnostic markers of MDS as well as for a drug efficacy evaluation. This paper reviews the research status of three animal models and a new spontaneous mouse model with MDS.

Activation of targetable inflammatory immune signaling is seen in myelodysplastic syndromes with SF3B1 mutations.

Mutations in the SF3B1 splicing factor are commonly seen in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), yet the specific oncogenic pathways activated by mis-splicing have not been fully elucidated. Inflammatory immune pathways have been shown to play roles in the pathogenesis of MDS, though the exact mechanisms of their activation in splicing mutant cases are not well understood. RNA-seq data from SF3B1 mutant samples was analyzed and functional roles of interleukin-1 receptor-associated kinase 4 (IRAK4) isoforms were determined. Efficacy of IRAK4 inhibition was evaluated in preclinical models of MDS/AML. RNA-seq splicing analysis of SF3B1 mutant MDS samples revealed retention of full-length exon 6 of IRAK4, a critical downstream mediator that links the Myddosome to inflammatory NF-kB activation. Exon 6 retention leads to a longer isoform, encoding a protein (IRAK4-long) that contains the entire death domain and kinase domain, leading to maximal activation of NF-kB. Cells with wild-type SF3B1 contain smaller IRAK4 isoforms that are targeted for proteasomal degradation. Expression of IRAK4-long in SF3B1 mutant cells induces TRAF6 activation leading to K63-linked ubiquitination of CDK2, associated with a block in hematopoietic differentiation. Inhibition of IRAK4 with CA-4948, leads to reduction in NF-kB activation, inflammatory cytokine production, enhanced myeloid differentiation in vitro and reduced leukemic growth in xenograft models. SF3B1 mutation leads to expression of a therapeutically targetable, longer, oncogenic IRAK4 isoform in AML/MDS models. This work was supported by Cincinnati Children's Hospital Research Foundation, Leukemia Lymphoma Society, and National Institute of Health (R35HL135787, RO1HL111103, RO1DK102759, RO1HL114582), Gabrielle's Angel Foundation for Cancer Research, and Edward P. Evans Foundation grants to DTS. AV is supported by Edward P. Evans Foundation, National Institute of Health (R01HL150832, R01HL139487, R01CA275007), Leukemia and Lymphoma Society, Curis and a gift from the Jane and Myles P. Dempsey family. AP and JB are supported by Blood Cancer UK (grants 13042 and 19004). GC is supported by a training grant from NYSTEM. We acknowledge support of this research from The Einstein Training Program in Stem Cell Research from the Empire State Stem Cell Fund through New York State Department of Health Contract C34874GG. MS is supported by a National Institute of Health Research Training and Career Development Grant (F31HL132420).

Myeloid-Derived Suppressor Cells: New Insights into the Pathogenesis and Therapy of MDS.

Myelodysplastic syndromes (MDS) are hematopoietic malignancies characterized by the clonal expansion of hematopoietic stem cells, bone marrow failure manifested by cytopenias, and increased risk for evolving to acute myeloid leukemia. Despite the fact that the acquisition of somatic mutations is considered key for the initiation of the disease, the bone marrow microenvironment also plays significant roles in MDS by providing the right niche and even shaping the malignant clone. Aberrant immune responses are frequent in MDS and are implicated in many aspects of MDS pathogenesis. Recently, myeloid-derived suppressor cells (MDSCs) have gained attention for their possible implication in the immune dysregulation associated with MDS. Here, we summarize the key findings regarding the expansion of MDSCs in MDS, their role in MDS pathogenesis and immune dysregulation, as well their potential as a new therapeutic target for MDS.

The Latest Research Progress on Myelodysplastic Syndrome Patient-derived Mesenchymal Stem Cell--Review

Myelodysplastic syndrome (MDS) are a heterogeneous group of hematological malignancies. Currently, in addition to demethylated chemotherapy and hematopoietic stem cell transplantation, MDS patient-derived mesenchymal stem cells (MDS-MSC) play an important role in understanding the pathogenesis of MDS and related therapeutic targets. For example, abnormal expression of DICER1 gene, abnormalities of PI3K/AKT and Wnt/β-catenin signaling pathways provide new therapeutic targets for MDS. In addition, MDS-MSC is also affected by abnormal microenvironment of the body, such as inflammatory factor S100A9, as well as hypercoagulation and iron overload. In this review, genes, signaling pathways, cytokines, hematopoietic microenvironment, and the effect of therapeutic drugs for MDS-MSC were briefly summarized.

Cytogenetic and Genetic Abnormalities with Diagnostic Value in Myelodysplastic Syndromes (MDS): Focus on the Pre-Messenger RNA Splicing Process.

Myelodysplastic syndromes (MDS) are considered to be diseases associated with splicing defects. A large number of genes involved in the pre-messenger RNA splicing process are mutated in MDS. Deletion of 5q and 7q are of diagnostic value, and those chromosome regions bear the numbers of splicing genes potentially deleted in del(5q) and del(7q)/-7 MDS. In this review, we present the splicing genes already known or suspected to be implicated in MDS pathogenesis. First, we focus on the splicing genes located on chromosome 5 (HNRNPA0, RBM27, RBM22, SLU7, DDX41), chromosome 7 (LUC7L2), and on the SF3B1 gene since both chromosome aberrations and the SF3B1 mutation are the only genetic abnormalities in splicing genes with clear diagnostic values. Then, we present and discuss other splicing genes that are showing a prognostic interest (SRSF2, U2AF1, ZRSR2, U2AF2, and PRPF8). Finally, we discuss the haploinsufficiency of splicing genes, especially from chromosomes 5 and 7, the important amplifier process of splicing defects, and the cumulative and synergistic effect of splicing genes defects in the MDS pathogenesis. At the time, when many authors suggest including the sequencing of some splicing genes to improve the diagnosis and the prognosis of MDS, a better understanding of these cooperative defects is needed.

Diagnosis of Myelodysplastic Syndromes: From Immunological Observations to Clinical Applications.

Myelodysplastic syndromes (MDS) constitute a very heterogeneous group of diseases with a high prevalence in elderly patients and a propensity for progression to acute myeloid leukemia. The complexity of these hematopoietic malignancies is revealed by the multiple recurrent somatic mutations involved in MDS pathogenesis and the paradoxical common phenotype observed in these patients characterized by ineffective hematopoiesis and cytopenia. In the context of population aging, the incidence of MDS will strongly increase in the future. Thus, precise diagnosis and evaluation of the progression risk of these diseases are imperative to adapt the treatment. Dysregulations of both innate and adaptive immune systems are frequently detected in MDS patients, and their critical role in MDS pathogenesis is now commonly accepted. However, different immune dysregulations and/or dysfunctions can be dynamically observed during the course of the disease. Monitoring the immune system therefore represents a new attractive tool for a more precise characterization of MDS at diagnosis and for identifying patients who may benefit from immunotherapy. We review here the current knowledge of the critical role of immune dysfunctions in both MDS and MDS precursor conditions and discuss the opportunities offered by the detection of these dysregulations for patient stratification.

Whole-Genome DNA Methylation Sequencing Reveals Epigenetic Changes in Myelodysplastic Syndromes.

Epigenetic dysregulation of cancer-associated genes has been identified to contribute to the pathogenesis of myelodysplastic syndromes (MDS). However, few studies have elucidated the whole-genome DNA methylation in the initiation pathogenesis of MDS. Reduced representation bisulfite sequencing was performed in five de novo MDS patients and four controls to investigate epigenetic alterations in MDS pathogenesis. The mean global methylation in five MDS patients showed no significant difference compared with the four controls. In depth, a total of 1,459 differentially methylated fragments, including 759 hypermethylated and 700 hypomethylated fragments, were identified between MDS patients and controls. Targeted bisulfite sequencing further identified that hypermethylation of DLEU7, FOXR1, LEP, and PANX2 were frequent events in an additional cohort of MDS patients. Subsequently, LEP hypermethylation was confirmed by real-time quantitative methylation-specific PCR in an expanded cohort of larger MDS patients. In clinics, LEP hypermethylation tended to be associated with lower bone marrow blasts and was significantly correlated with U2AF1 mutation. Survival analysis indicated that LEP hypermethylation was associated with a markedly longer survival time but was not an independent prognostic biomarker in MDS patients. Functional studies revealed pro-proliferative and anti-apoptotic effects of leptin in the MDS cell line SKM-1, and it was significantly associated with cell growth and death as well as the Toll-like receptor and NF-kappa B signaling pathways. Collectively, our findings demonstrated that whole-genome DNA methylation analysis identified novel epigenetic alterations such as DLEU7, FOXR1, LEP, and PANX2 methylations as frequent events in MDS. Moreover, LEP might play a role in MDS pathogenesis, and LEP hypermethylation was associated with longer survival but not as an independent prognostic biomarker in MDS.

P730: GENETIC LANDSCAPE OF SOMATIC MYELOID MUTATIONS IN THE PRESENCE OF RARE TERT VARIANTS AND THEIR RELATION WITH MYELOID NEOPLASIA

Background: Genetic variants in TERT, the gene that encodes telomerase reverse transcriptase, can result in accelerated telomere attrition. Impaired telomere maintenance is implicated in the pathogenesis of myelodysplastic syndromes (MDS), with mechanisms remaining to be elucidated. Aims: To explore the clinical and genetic associations of TERT variants in an unselected cohort of patients screened with a myeloid mutation next generation sequencing panel due to clinical suspicion of a myeloid neoplasia. Methods: Using a research protocol approved by the Mayo Clinic Institutional Review Board, we performed a retrospective chart review to identify a cohort of unselected individuals within all historical data at our institution that had undergone somatic mutational analysis for suspected myeloid neoplasia using our insitutional amplicon based next generation sequencing panel (42 genes, including exons 2 to 16 of TERT, with a read depth of at least 250X). TERT variants were classified into those with CADD score >20 and <20 in line with previous literature to identify variants within the top 1% according to their predicted deleteriousness. Additionally, we identified within our cohort individuals that received a diagnosis of MDS, clinical and survival information. Results: We identified 55 different TERT variants (46 missense, 3 in canonical splice sites, 4 synonymous and 2 small inframe deletions) in 148 individuals tested from April of 2016 to November of 2021 (Fig. 1A&B). The five most recurrent variants were c.1234C>T (48 patients), c.1323_1325del (29 patients), c.3164C>T (5 patients), c.604G>A (4 patients) and c.969G>A (4 patients), all with CADD<20. None of these patients were diagnosed with a bona fide telomere biology disorder and no clinical information about telomere length status was available. All variants were considered germline since their allele frequency was near 50%, although no germline confirmation was performed. All variants were clinically classified as uncertain significance according to the American College of Medical Genetics guidelines. Of the 148 total patients, 17 (12%) carried TERT variants with CADD>20 that were distributed thorough all the gene domains with no clustering or presence of hotspots (Fig.1A&B). 59% (10 patients) of CADD>20 variants carriers were diagnosed with MDS: 5 patients with <5% bone marrow blasts (4 with normal karyotype) and 5 patients with 5-19% blasts, all with complex karyotype. This percentage was significantly higher compared to CADD<20 variant carriers (34%, 49 patients, p=0.048 by Chi-square test, Fig. 1C). However, no major differences were found between the two groups in terms of age at diagnosis (median 70 vs 73 years old, p = 0.2305) or AML-free survival (median 10 vs 15.5 months since diagnosis, p=0.4674). Similarly, the percentage of patients presenting additional somatic variants in other myeloid-related genes was similar between CADD<20 and CADD>20 TERT variant carriers (60% vs 64%). The two most frequenly mutated genes in CADD>20 carriers were TP53 (22%), TET2 (18%), RUNX1 (9%), U2AF1 (9%) and BCOR (9%) while in the CADD<20 carriers were TET2 (14%), ASXL1 (11%), SRSF2 (9%), TP53 (7%) and JAK2 (6%). Our data showed that TP53 pathogenic variants were significantly enriched in CADD>20 TERT variant carriers compared to CADD<20 carriers. (22.7% vs 7.4%, p=0.0169, Fig. 1D). Image:Summary/Conclusion: Carriers of TERT variants with CADD score of >20 were more likely to be associated with a diagnosis of MDS and with somatic TP53 mutations in comparison to those with CADD score <20, findings that we plan to validate functionally and prospectively.

P733: DHX9 HELICASE DYSFUNCTION CONTRIBUTES TO DISEASE PROGRESSION IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES

Background:DHX9 is a member of the DEAH (Asp-Glu-Ala-His) helicase family, and participates in regulating DNA replication and RNA processing. DHX9 dysfunction promotes tumorigenesis in several solid cancers. However, the role of DHX9 in myelodysplastic syndromes (MDS) is still unknown. Aims: to investigate the role of DHX9 in the pathogenesis of myelodysplastic syndromes. Methods:DHX9 expression was analyzed in 120 MDS patients and 42 non-MDS benign controls by quantitative PCR. Clinical significance of changes in DHX9 expression was investigated in disease progression and survival. Lentivirus-mediated DHX9 knockdown experiments were performed to investigate its biological function. The mechanistic involvement of DHX9 in MDS development was explored in cell functional assays, gene microarray and pharmacological intervention. Considering the importance of DHX9 in regulation of R-loop, we also investigated the role of DHX9 and R-loop in MDS. Results: We found that overexpression of DHX9 is frequent in MDS patients, and associated with poor survival and high risk of AML transformation. Cell functional assays showed that DHX9 is essential for the maintenance of malignant proliferation of leukemia cells, and knockdown of DHX9 results in increased cell apoptosis and growth inhibition. Gene expression profile and bioinformatics analysis reveal that DHX9 may be involved in PI3K-AKT signaling pathways. Validating experiments show that DHX9 is indispensable for the activation of PI3K-AKT signaling as knockdown of DHX9 inactivates the PI3K-AKT signaling, reduces the expression of anti-apoptosis genes such as CCND2, MYC and BCL2. In addition, we found that DHX9 knockdown leads to R-loop accumulation in MDS cells, and induces R-Loop-dependent DNA damage through ATR-Chk1 activation. It suggests that overexpressed DHX9 could counteract cell growth defect caused by R-Loop which is quite common in MDS patients especially in those with splicing genes mutations. Summary/Conclusion: Our data suggest that DHX9 contributes to disease progression by activation of PI3K-AKT signaling and correcting R-loop-mediated growth defect in MDS, and may serve as a novel prognostic marker for AML transformation and therapeutic target in MDS.

Apoptosis in myelodysplasia: Association with patient age, bone marrow cellularity and karyotypes

Background: Myelodysplastic syndrome (MDS) comprises a heterogeneous group of clonal hematopoietic stem cell diseases, characterized by dysplasias and apoptosis in bone marrow (BM) and cytopenias in peripheral blood. In this study, we analyzed apoptosis in MDS to verify associations with patient age, bone marrow cellularity and karyotypes and to investigate the role of apoptosis in MDS pathogenesis. Methods: Bone marrow cells were collected from 81 patients with primary MDS, of which 60 were adults and 21 children. BM cells were also collected from 10 healthy donors for bone marrow transplants, 5 adults and 5 children, as controls. The patients and controls came from public onco-hematology institutions in Rio de Janeiro. The percentage of apoptotic BM cells was assessed by flow cytometry using two combinations: annexin V-FITC/CD34PE/CD45PerCP and annexin V-FITC/CD14PE/CD45PerCP in BM cells. Cytogenetic analysis was performed by G-banding. Results: The comparison between adult and pediatric patients showed that these patients show a similar behavior with regard to apoptotic cells percentages in BM samples. Apoptosis occurs independently of BM cellularity, being more prominent in patients with hyper/normocellular BM. Patients with normal karyotypes, del(5q), del(17p) had higher apoptosis rates than patients with del(11q) and complex karyotypes. Cells committed to a differentiation program were associated with high rates of apoptosis, suggesting that apoptosis may be a consequence of inefficient hematopoiesis, such that the hematopoietic system may eliminate dysplastic cells at the beginning of the disease. Conclusions: Our results suggest that apoptosis is an important characteristic of BM cells from adult and pediatric MDS patients and may be a consequence of inefficient hematopoiesis. In addition, we suggest that apoptosis is not the main mechanism associated with hypocellular MDS, and it occurs preferentially in MDS cases of hyper/normocellular BM and is associated with a good prognosis. Keywords: Myelodysplastic Syndrome; Apoptosis; Patient age; Bone marrow cellularity; Karyotypes.

Miyelodisplastik sendrom hastalığında P53 polimorfizmlerinin önemi

Amaç: Miyelodisplastik sendrom (MDS) akut miyeloid lösemiye dönüşüm riski yüksek olan, artmış apoptozis ve azalmış hematopoez oranlarıyla karakterize klonal bir hastalıktır. MDS patogenezi tam olarak açıklanabilmiş değildir. Olguların ~%50' si anormal karyotiptedir ve bu oran ikincil MDS' de %80 civarındadır. P53 proteini kök hücre homeostazının önemli düzenleyicisidir ve hücre döngüsünün düzenlenmesi, apoptotik ile enflamatuar yanıt gibi bir dizi hücresel olayda yer alır. Genomik bütünlüğün korunmasında da önemli görevleri bulunan TP53 geni kanserlerde sıklıkla mutasyona uğramaktadır; ancak, mutasyonlarının yanında bazı gen polimorfizmlerinin de kanserle ilişkili oldukları bilinmektedir. Çalışmadaki amacımız, dört yaygın p53 tek nükleotid polimorfizminin MDS’ deki yaygınlıklarını ve hastalık gelişimi üzerine etkilerini belirlemektir. Bu amaçla, Ege Üniversitesi Tıp Fakültesi Dahiliye Anabilim Dalı Hematoloji Bilim Dalı' nda MDS tanısı ile takip edilen ya da yeni tanı almış 100 olgu çalışmaya dahil edildi. Gereç ve Yöntem: MDS’li olguların periferik kan lökositlerinden izole edilen DNA’lar gerçek-zamanlı PCR yöntemiyle çalışılarak, p53 polimorfizmleri (rs35163653, rs35993958, rs1800371, rs1042522) uygun probların kullanımıyla ve erime eğrisi analizleriyle belirlendi. Bulgular: İncelenen dört yaygın p53 polimorfizmin arasında özellikle rs1042522 polimorfizmindeki atasal olmayan G alelinin MDS’li olgularda artmış olduğu gözlenmiştir (C:%30.3; G:%69.7). Fonksiyonel olduğu, yani sentez edilen proteinin fonksiyonunu etkilediği bilinen bu polimorfizmde 417. pozisyonundaki C nukleotidinin G’ye transisyonu (C&amp;gt;G), proteinin 72. pozisyonundaki prolin amino asidinin arjinine (P72R) kodlanmasına yol açmaktadır. Sonuç: Çalışmamız, MDS hastalık grubunda rs35163653, rs35993958, rs1800371 ve rs1042522 p53 polimorfizmlerinin araştırıldığı ilk çalışmadır. Bunlardan, rs1042522 polimorfizminin kansere yatkınlık ve duyarlılıkla ilişkili olduğu yapılan diğer bazı çalışmalarla gösterilmiş olması nedeniyle, MDS hastalığı için de yüksek risk oluşturabileceği düşünülmektedir. Sonuç olarak, MDS hastalığı için gerçekleştirilen bu çalışmanın daha geniş bir olgu grubuyla tekrarlanmasıyla rs1042522 polimorfizmi ileride MDS teşhisinde belirteç olarak kullanılabilecektir.

Bioinformatics Analysis of Core Genes and Key Pathways in Myelodysplastic Syndrome

To screen differentially expressed gene (DEG) related to myelodysplastic syndrome (MDS) based on Gene Expression Omnibus (GEO) database, and explore the core genes and pathogenesis of MDS by analyzing the biological functions and related signaling pathways of DEG. The expression profiles of GSE4619, GSE19429, GSE58831 including MDS patients and normal controls were downloaded from GEO database. The gene expression analysis tool (GEO2R) of GEO database was used to screen DEG according to | log FC (fold change) |≥1 and P<0.01. David online database was used to annotate gene ontology function (GO). Metascape online database was used to enrich and analyze differential genes in Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein-protein interaction network (PPI) was constructed by using STRING database. CytoHubba and Mcode plug-ins of Cytoscape were used to analyze the key gene clusters and hub genes. R language was used to diagnose hub genes and draw the ROC curve. GSEA enrichment analysis was performed on GSE19429 according to the expression of LEF1. A total of 74 co-DEG were identified, including 14 up-regulated genes and 60 down regulated genes. GO enrichment analysis indicated that BP of down regulated genes was mainly enriched in the transcription and regulation of RNA polymerase II promoter, negative regulation of cell proliferation, and immune response. CC of down regulated genes was mainly enriched in the nucleus, transcription factor complexes, and adhesion spots. MF was mainly enriched in protein binding, DNA binding, and β-catenin binding. KEGG pathway was enriched in primary immunodeficiency, Hippo signaling pathway, cAMP signaling pathway, transcriptional mis-regulation in cancer and hematopoietic cell lineage. BP of up-regulated genes was mainly enriched in type I interferon signaling pathway and viral response. CC was mainly enriched in cytoplasm. MF was mainly enriched in RNA binding. Ten hub genes and three important gene clusters were screened by STRING database and Cytoscape software. The functions of the three key gene clusters were closely related to immune regulation. ROC analysis showed that the hub genes had a good diagnostic significance for MDS. GSEA analysis indicated that LEF1 may affect the normal function of hematopoietic stem cells by regulating inflammatory reaction, which further revealed the pathogenesis of MDS. Bioinformatics can effectively screen the core genes and key signaling pathways of MDS, which provides a new strategy for the diagnosis and treatment of MDS.

Relationship of HIF‑1α expression with apoptosis and cell cycle in bone marrow mesenchymal stem cells from patients with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is a group of abnormal clonal disorders with ineffective hematopoiesis, which are incurable with conventional therapy. Of note, MDS features an abnormal bone marrow microenvironment, which is related to its incidence. The hypoxia-inducible factor-1α (HIF-1α) transcriptional signature is generally activated in bone marrow stem/progenitor cells of patients with MDS. To analyze the expression of HIF-1α in bone marrow mesenchymal stem cells (BM-MSCs) and the apoptosis and cell cycle features associated with the disease, BM-MSCs were obtained from 40 patients with a definitive diagnosis of MDS and 20 subjects with hemocytopenia but a negative diagnosis of MDS as a control group. Reverse transcription-quantitative PCR and western blot analyses were used to measure HIF-1α expression in cells from the two groups and apoptosis and cell cycle were also analyzed and compared between the groups using flow cytometry assays. BM-MSCs from both the control group and the MDS group exhibited a fibroblast-like morphology, had similar growth cycles and were difficult to passage stably. It was observed that BM-MSCs from the MDS group had significantly higher HIF-1α expression levels than the control group (P<0.05). Furthermore, the BM-MSCs from the MDS group had a higher proportion of cells in early apoptosis (5.22±1.34 vs. 2.04±0.08%; P<0.0001) and late apoptosis (3.38±0.43 vs. 1.23±0.11%; P<0.01) and exhibited cell cycle arrest. This may be a noteworthy aspect of the pathogenesis of MDS and may be related to high HIF-1α expression under a hypoxic state in the bone marrow microenvironment. Furthermore, the expression of HIF-1α in bone marrow tissue sections from patients with MDS in the International Prognostic Scoring System (IPSS) lower-risk group was higher than that from patients with MDS in the IPSS high-risk group. These results revealed the role of HIF-1α as a central pathobiology mediator of MDS and an effective therapeutic target for a broad spectrum of patients with MDS, particularly for patients in the lower-risk group.

Pathophysiologic and clinical implications of molecular profiles resultant from deletion 5q.

SummaryBackgroundHaploinsufficiency (HI) resulting from deletion of the long arm of chromosome 5 [del(5q)] and the accompanied loss of heterozygosity are likely key pathogenic factors in del(5q) myeloid neoplasia (MN) although the consequences of del(5q) have not been yet clarified.MethodsHere, we explored mutations, gene expression and clinical phenotypes of 388 del(5q) vs. 841 diploid cases with MN [82% myelodysplastic syndromes (MDS)].FindingsDel(5q) resulted as founder (better prognosis) or secondary hit (preceded by TP53 mutations). Using Bayesian prediction analyses on 57 HI marker genes we established the minimal del(5q) gene signature that distinguishes del(5q) from diploid cases. Clusters of diploid cases mimicking the del(5q) signature support the overall importance of del(5q) genes in the pathogenesis of MDS in general. Sub-clusters within del(5q) patients pointed towards the inherent intrapatient heterogeneity of HI genes.InterpretationThe underlying clonal expansion drive results from a balance between the “HI-driver” genes (e.g., CSNK1A1, CTNNA1, TCERG1) and the proapoptotic “HI-anti-drivers” (e.g., RPS14, PURA, SIL1). The residual essential clonal expansion drive allows for selection of accelerator mutations such as TP53 (denominating poor) and CSNK1A1 mutations (with a better prognosis) which overcome pro-apoptotic genes (e.g., p21, BAD, BAX), resulting in a clonal expansion. In summary, we describe the complete picture of del(5q) MN identifying the crucial genes, gene clusters and clonal hierarchy dictating the clinical course of del(5q) patients.FundingTorsten Haferlach Leukemia Diagnostics Foundation. US National Institute of Health (NIH) grants R35 HL135795, R01HL123904, R01 HL118281, R01 HL128425, R01 HL132071, and a grant from Edward P. Evans Foundation.

Gut Microbiome and Plasma Metabolomic Analysis in Patients with Myelodysplastic Syndrome.

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders. Studies have shown the involvement of an abnormal immune system in MDS pathogenesis. The gut microbiota are known to influence host immunity and metabolism, thereby contributing to the development of hematopoietic diseases. In this study, we performed gut microbiome and plasma metabolomic analyses in patients with MDS and healthy controls. We found that patients with MDS had a different gut microbial composition compared to controls. The gut microbiota in MDS patients showed a continuous evolutionary relationship from the phylum to the species level. At the species level, the abundance of Haemophilus parainfluenzae, Streptococcus luteciae, Clostridium citroniae, and Gemmiger formicilis increased, while that of Prevotella copri decreased in MDS patients compared to controls. Moreover, abundance of bacterial genera correlated with the percentage of lymphocyte subsets in patients with MDS. Metabolomic analysis showed that the concentrations of hypoxanthine and pyroglutamic acid were increased, while that of 3a,7a-dihydroxy-5b-cholestan was decreased in MDS patients compared to controls. In conclusion, gut microbiome and plasma metabolomics are altered in patients with MDS, which may be involved in the immunopathogenesis of the disease.

Inflammatory Cytokine Profiles Do Not Differ Between Patients With Idiopathic Cytopenias of Undetermined Significance and Myelodysplastic Syndromes.

Immune dysregulation has been highlighted as a key player in the pathogenesis of myelodysplastic syndromes (MDS), but little is known about cytokine profiles in patients with unexplained cytopenia with or without mutations in MDS-associated genes (clonal cytopenias of undetermined significance [CCUS] and idiopathic cytopenias of undetermined significance [ICUS], respectively), which often precede MDS. Here, we study the cytokine profiles in 111 patients with ICUS (N = 41), CCUS (N = 30), lower-risk MDS (LR-MDS; N = 22) and higher-risk MDS (HR-MDS; N = 18), and in healthy elderly controls (N = 21). Twenty cytokines were examined in blood plasma at time of diagnosis using Luminex assays and enzyme linked immunosorbent assays. The cytokine levels were compared between patient groups, and in patients versus controls. Associations between cytokines and MDS-associated mutations were evaluated. An aberrant cytokine profile was observed in all patient groups relative to healthy elderly controls. Patients had significantly higher levels of IL-6 (P< 0 .001), tumor necrosis factor α (P < 0.001), IL-10 (P < 0.001), and C-X-C motif chemokine 10 (P < 0.001) and lower levels of transforming growth factor beta 1 (P < 0.001), CCL5/regulated on activation normal T-cell expressed and secreted (P < 0.001), and S100A4 (P < 0.001) compared with healthy controls. Survival was significantly shorter in CCUS and MDS patients with a high systemic inflammatory cytokine load (median overall survival [OS] 21 months) compared with those with low-moderate systemic inflammatory cytokine load (median OS 64 months; P < 0.0001). These data suggest that patients with ICUS and CCUS have cytokine levels as abnormal as in LR-MDS. Indeed, high cytokine levels are present before MDS is diagnosed and cytokine levels are elevated irrespective of the presence or size of the myeloid clones. Cytokines may have a prognostic impact at a very early premalignant stage of myeloid disorders.

Efficacy and Safety of Hypomethylating Agents in Chronic Myelomonocytic Leukemia: A Single-Arm Meta-analysis.

Background Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm with features of the myelodysplastic syndromes (MDSs) and myeloproliferative neoplasm presenting with peripheral blood monocytosis and an inherent risk for transformation to acute myeloid leukemia, while the abnormal DNA methylation plays a critical role in the pathogenesis of MDS, which is a disease of disordered differentiation. Recently, with the rapid development of molecular biology, hypomethylating agents (HMAs) for the treatment of MDS has gradually become a research focus. The objective of this study was to evaluate the benefits and risks of HMAs for patients with CMML. Materials and Methods PubMed, Embase, the Cochrane Library, and three Chinese databases were searched for studies published before November 2020 that used HMAs in CMML. Results The pooled objective response rate (ORR), complete response (CR), and partial response (PR) were 50.0, 21.0, and 2.0%, respectively. The proportion of patients with minor response (MR) was significantly higher for decitabine (DAC) than for azacitidine (AZA). There was no significant difference in hematologic improvement, ORR, CR, and PR rates between the DAC and AZA groups. Hematological toxicity included neutropenia grade 3/4 (14.0%), anemia grade 3/4 (17.0%), and thrombocytopenia grade 3/4 (22.0%). Conclusion This study showed that HMAs were effective and safe in the treatment of CMML, but large multicenter study would be needed to confirm the efficacy of HMAs for the treatment of CMML with different risk level and genetic abnormality, to support individualization treatment theoretically.