Genetic basis of myelodysplastic syndromes

Myelodysplastic Syndrome: Clinical Characteristics and Significance of Preclinically Detecting Biallelic Mutations in the TET2 Gene

Myelodysplastic syndrome (MDS) is a clonal disease derived from hematopoietic stem cells, characterized by ineffective hematopoiesis (resulting in peripheral blood cytopenia) and an increased risk of transformation into acute myeloid leukemia. MDS is caused by a complex combination of genetic mutations resulting in a heterogeneous genotype. Genetic studies have identified a set of aberrations that play a central role in the pathogenesis of MDS. In this article, we present a clinical case of MDS transformation into acute myeloid leukemia in the context of two cell lines exhibiting morphological, immunophenotypic, and dysmyelopoiesis markers and the presence of two heterozygous mutations in the TET2 gene.

Tumor-suppressive functions of protein lysine methyltransferases

Protein lysine methyltransferases (PKMTs) play crucial roles in histone and nonhistone modifications, and their dysregulation has been linked to the development and progression of cancer. While the majority of studies have focused on the oncogenic functions of PKMTs, extensive evidence has indicated that these enzymes also play roles in tumor suppression by regulating the stability of p53 and β-catenin, promoting α-tubulin-mediated genomic stability, and regulating the transcription of oncogenes and tumor suppressors. Despite their contradictory roles in tumorigenesis, many PKMTs have been identified as potential therapeutic targets for cancer treatment. However, PKMT inhibitors may have unintended negative effects depending on the specific cancer type and target enzyme. Therefore, this review aims to comprehensively summarize the tumor-suppressive effects of PKMTs and to provide new insights into the development of anticancer drugs targeting PKMTs.

Real-world practice-based prognostic model for higher-risk myelodysplastic syndromes treated with azacitidine monotherapy: The Kyoto prognostic scoring system

The prognostic impact of patient-related factors, including age, nutritional parameters, and inflammation status, in higher-risk myelodysplastic syndromes (HR-MDS) has been largely unexplored. This multicenter retrospective study aimed to establish a real-world practice-based prognostic model for HR-MDS by considering both disease- and patient-related parameters in 233 patients treated with AZA monotherapy at seven institutions. We found that anemia, presence of circulating blasts in peripheral blood, low absolute lymphocyte count, low total cholesterol (T-cho) and albumin serum levels, complex karyotype, and del(7q) or  - 7 were poor prognostic factors. Therefore, we developed a new prognostic model called the Kyoto Prognostic Scoring System (KPSS) by incorporating the two variables with the highest C-indexes (complex karyotype and serum T-cho level). The KPSS classified patients into the following three groups: good (0 risk factors), intermediate (1), and poor (2). Median overall survival for these groups was 24.4, 11.3, and 6.9, respectively (p < 0.001). The discriminatory power of the KPSS was higher than that of the traditional International Prognostic Scoring System. In conclusion, we identified several nutritional parameters with prognostic relevance in patients with HR-MDS and generated a prognostic model consisting of complex karyotype and serum T-cho level that enabled excellent risk stratification.

Emerging treatments for myelodysplastic syndromes: Biological rationales and clinical translation

Myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by myeloid dysplasia, peripheral blood cytopenias, and increased risk of progression to acute myeloid leukemia (AML). The standard of care for patients with MDS is hypomethylating agent (HMA)-based therapy; however, nearly 50% of patients have no response to the treatment. Patients with MDS in whom HMA therapy has failed have a dismal prognosis and no approved second-line therapy options, so enrollment in clinical trials of experimental agents represents these patients' only chance for improved outcomes. A better understanding of the molecular and biological mechanisms underpinning MDS pathogenesis has enabled the development of new agents that target molecular alterations, cell death regulators, signaling pathways, and immune regulatory proteins in MDS. Here, we review novel therapies for patients with MDS in whom HMA therapy has failed, with an emphasis on the biological rationale for these therapies' development.

A machine learning model of response to hypomethylating agents in myelodysplastic syndromes

Hypomethylating agents (HMA) prolong survival and improve cytopenias in individuals with higher-risk myelodysplastic syndrome (MDS). Only 30-40% of patients, however, respond to HMAs, and responses may not occur for more than 6 months after HMA initiation. We developed a model to more rapidly assess HMA response by analyzing early changes in patients’ blood counts. Three institutions’ data were used to develop a model that assessed patients’ response to therapy 90 days after the initiation using serial blood counts. The model was developed with a training cohort of 424 patients from 2 institutions and validated on an independent cohort of 90 patients. The final model achieved an area under the receiver operating characteristic curve (AUROC) of 0.79 in the train/test group and 0.84 in the validation group. The model provides cohort-wide and individual-level explanations for model predictions, and model certainty can be interrogated to gauge the reliability of a given prediction.

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We developed a model to more rapidly assess patients’ response to hypomethylating agents

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The model’s predictions use exclusively routinely collected blood count data

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The model confirmed prior findings and identified potential new prognostic factors

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Model predictions are interpretable on both the individual and cohort-wide level

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.

Epigenetic traits inscribed in chromatin accessibility in aged hematopoietic stem cells

Hematopoietic stem cells (HSCs) exhibit considerable cell-intrinsic changes with age. Here, we present an integrated analysis of transcriptome and chromatin accessibility of aged HSCs and downstream progenitors. Alterations in chromatin accessibility preferentially take place in HSCs with aging, which gradually resolve with differentiation. Differentially open accessible regions (open DARs) in aged HSCs are enriched for enhancers and show enrichment of binding motifs of the STAT, ATF, and CNC family transcription factors that are activated in response to external stresses. Genes linked to open DARs show significantly higher levels of basal expression and their expression reaches significantly higher peaks after cytokine stimulation in aged HSCs than in young HSCs, suggesting that open DARs contribute to augmented transcriptional responses under stress conditions. However, a short-term stress challenge that mimics infection is not sufficient to induce persistent chromatin accessibility changes in young HSCs. These results indicate that the ongoing and/or history of exposure to external stresses may be epigenetically inscribed in HSCs to augment their responses to external stimuli.

Haematopoietic stem cells (HSCs) exhibit considerable cell-intrinsic changes with age. Here the authors demonstrate that differentially accessible regions in aged HSC chromatin are enriched for stress-responsive enhancers and act as an epigenetic hub to augment transcriptional responses of aged HSCs to external stimuli.

How do molecular aberrations guide therapy in MDS?

Myelodysplastic syndromes (MDS) represent a cluster of genetically and phenotypically heterogeneous hematological disorders. While molecularly targeted therapies have entered the standard of care for other hematological malignancies like acute myeloid leukemia, this approach has been elusive in MDS. This review has summarized recent evidence to determine how molecular aberrations can be used to guide therapy in MDS and improve outcomes among patients.

Molecular Targeted Therapy in Myelodysplastic Syndromes: New Options for Tailored Treatments

Simple Summary

Myelodysplastic syndromes (MDS) are a group of diseases in which bone marrow stem cells acquire genetic alterations and can initiate leukemia, blocking the production of mature blood cells. It is of crucial importance to identify those genetic abnormalities because some of them can be the targeted. To date only very few drugs are approved for patients manifesting this group of disorders and there is an urgent need to develop new effective therapies. This review gives an overview of the genetic of MDS and the therapeutic options available and in clinical experimentation.

Abstract

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic disorders characterized by ineffective hematopoiesis, progressive cytopenias and increased risk of transformation to acute myeloid leukemia. The improved understanding of the underlying biology and genetics of MDS has led to better disease and risk classification, paving the way for novel therapeutic opportunities. Indeed, we now have a vast pipeline of targeted agents under pre-clinical and clinical development, potentially able to modify the natural history of the diverse disease spectrum of MDS. Here, we review the latest therapeutic approaches (investigational and approved agents) for MDS treatment. A deep insight will be given to molecularly targeted therapies by reviewing new agents for individualized precision medicine.

Autophagy Gene Panel-Based Prognostic Model in Myelodysplastic Syndrome

Abnormal autophagy is related to the pathogenesis and clinical symptoms of myelodysplastic syndrome (MDS). However, the effect of autophagy-related genes (ARGs) on the prognosis of MDS remains unclear. Here, we examined the expression profile of 108 patients with MDS from the GSE58831 dataset, and identified 22 genes that were significantly associated with overall survival. Among them, seven ARGs were screened and APIs were calculated for all samples based on the expression of the seven ARGs, and then, MDS patients were categorized into high- and low-risk groups based on the median APIs. The overall survival of patients with high-risk scores based on these seven ARGs was shorter than patients with low-risk scores in both the training cohort (P = 2.851e-06) and the validation cohort (P = 9.265e-03). Additionally, API showed an independent prognostic indicator for survival in the training samples [hazard ratio (HR) = 1.322, 95% confidence interval (CI): 1.158–1.51; P < 0.001] and the validation cohort (HR = 1.05, 95% CI: 1–1.1; P < 0.01). The area under the receiver operating characteristic curve (AUROC) of API and IPSS were 43.0137 and 66.0274 in the training cohorts and the AUC of the validation cohorts were 41.5361 and 72.0219. Our data indicate these seven ARGs can predict prognosis in patients with MDS and could guide individualized treatment.

Acquired aplastic anemia: Is bystander insult to autologous hematopoiesis driven by immune surveillance against malignant cells?

We previously reported a serendipitous finding from a patient with refractory severe aplastic anemia who had gotten an unexpected hematological response to treatment with gut-cleansing preparations (GCPs). This patient experienced three recurrences over the ensuing one year of intermittent GCP treatments, with each recurrence occurring 7-8 wk from a GCP. After his third recurrence, he was prescribed successive treatment with rifampicin, berberine, and monthly administered GCP for 4 mo, and he developed an erythroid proliferative neoplasma and an overwhelming enteropathy, and eventually died of septic shock. Laboratory investigations had validated the resolution of myelosuppression and the appearance of malignant clonal hematopoiesis. From the treatment process and laboratory investigations, it is reasonably inferred that the engagement of gut inflammation is critically required in sustaining the overall pathophysiology of acquired aplastic anemia probably by creating a chronic inflammatory state. Incorporation of rifampicin, berberine, and monthly GCP into cyclosporine can enhance the immunosuppressive effect. In a subgroup of acquired aplastic anemia patients whose pathogenesis is associated with genotoxic exposure, the suppressed normal hematopoiesis may result from the bystander insult that is mediated by the soluble inflammatory cytokines generated in response to the immunogenic products of damaged hematopoietic cells in the context of chronic inflammatory state and may offer a protective antineoplastic mechanism against malignant proliferation.