Why do we not have more drugs approved for MDS? A critical viewpoint on novel drug development in MDS.

Approval of new agents to treat higher risk (HR) myelodysplastic syndrome (MDS) has stalled since the approval of DNA methyltransferase inhibitors (DNMTi). In addition, the options for patients with lower risk (LR) MDS who have high transfusion needs and do not harbor ring sideroblasts or 5q- syndrome are limited. Here, we review the current treatment landscape in MDS and identify areas of unmet need, such as treatment after failure of erythropoiesis-stimulating agents or DNMTis, TP53-mutated disease, and MDS with potentially targetable mutations. We discuss how our understanding of MDS pathogenesis can inform therapy development, including treating HR-MDS similarly to AML and pursuing therapies to address splicing factor mutations and dysregulated inflammation. We then bring a critical lens to current methodology of MDS studies and propose solutions to improve the efficiency and yield of these clinical trials, including using the most meaningful response metrics and expanding enrollment.

Impaired myelopoiesis in congenital neutropenia: insights into clonal and malignant hematopoiesis.

A common feature of both congenital and acquired forms of bone marrow failure is an increased risk of developing acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Indeed, the development of MDS or AML is now the major cause of mortality in patients with congenital neutropenia. Thus, there is a pressing clinical need to develop better strategies to prevent, diagnose early, and treat MDS/AML in patients with congenital neutropenia and other bone marrow failure syndromes. Here, we discuss recent data characterizing clonal hematopoiesis and progression to myeloid malignancy in congenital neutropenia, focusing on severe congenital neutropenia (SCN) and Shwachman-Diamond syndrome. We summarize recent studies showing excellent outcomes after allogenic hematopoietic stem cell transplantation for many (but not all) patients with congenital neutropenia, including patients with SCN with active myeloid malignancy who underwent transplantation. Finally, we discuss how these new data inform the current clinical management of patients with congenital neutropenia.

Therapeutic targeting of the inflammasome in myeloid malignancies.

Even though genetic perturbations and mutations are important for the development of myeloid malignancies, the effects of an inflammatory microenvironment are a critical modulator of carcinogenesis. Activation of the innate immune system through various ligands and signaling pathways is an important driver of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). The DAMPs, or alarmins, which activate the inflammasome pathway via the TLR4/NLR signaling cascade causes the lytic cell death of hematopoietic stem and progenitor cells (HSPCs), ineffective hematopoiesis, and ß-catenin-induced proliferation of cancer cells, leading to the development of MDS/AML phenotype. It is also associated with other myeloid malignancies and involved in the pathogenesis of associated cytopenias. Ongoing research suggests the interplay of inflammasome mediators with immune modulators and transcription factors to have a significant role in the development of myeloid diseases, and possibly therapy resistance. This review discusses the role and importance of inflammasomes and immune pathways in myeloid malignancies, particularly MDS/AML, to better understand the disease pathophysiology and decipher the scope of therapeutic interventions.

Dynamics of epigenetic regulator gene BCOR mutation and response predictive value for hypomethylating agents in patients with myelodysplastic syndrome.

BACKGROUND: BCOR (BCL6 corepressor) is an epigenetic regulator gene involved in the specification of cell differentiation and body structure development. Recurrent somatic BCOR mutations have been identified in myelodysplastic syndrome (MDS). However, the clinical impact of BCOR mutations on MDS prognosis is controversial and the response of hypomethylating agents in MDS with BCOR mutations (BCORMUT) remains unknown. RESULTS: Among 676 MDS patients, 43 patients (6.4%) harbored BCOR mutations. A higher frequency of BCOR mutations (8.7%) was investigated in patients with normal chromosome, compared to 4.2% in patients with abnormal karyotype (p = 0.040). Compared to the BCORWT patients, the BCORMUT patients showed a higher ratio of refractory anemia with excess blasts subset (p = 0.008). The most common comutations with BCOR genes were ASXL1 (p = 0.002), DNMT3A (p = 0.114) and TET2 (p = 0.148). When the hierarchy of somatic mutations was analyzed, BCOR mutations were below the known initial mutations (ASXL1 or TET2) but were above U2AF1 mutations. Transformation-free survival was significantly shorter in BCORMUT patients than that in BCORWT patients (16 vs. 35 months; p = 0.035). RNA-sequencing was performed in bone marrow mononuclear cells from BCORMUT and BCORWT patients and revealed 2030 upregulated and 772 downregulated genes. Importantly, HOXA6, HOXB7, and HOXB9 were significantly over-expressed in BCORMUT patients, compared to BCORWT patients. Eight of 14 BCORMUT patients (57.1%) achieved complete remission (CR) with decitabine treatment, which was much higher than that in BCORWT patients (28.7%, p = 0.036). Paired sequencing results (before and after decitabine) showed three of 6 CR patients lost the mutated BCOR. The median survival of CR patients with a BCORMUT was 40 months, which was significantly longer than that in patients with BCORWT (20 months, p = 0.036). Notably, prolonged survival was observed in three BCORMUT CR patients even without any subsequent therapies. CONCLUSIONS: BCOR mutations occur more frequently in CN MDS patients, predicting higher risk of leukemia transformation. BCORMUT patients showed a better response to decitabine and achieved longer post-CR survival.

Exploiting the Role of Hypoxia-Inducible Factor 1 and Pseudohypoxia in the Myelodysplastic Syndrome Pathophysiology.

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem (HSCs) and/or progenitor cells disorders. The established dependence of MDS progenitors on the hypoxic bone marrow (BM) microenvironment turned scientific interests to the transcription factor hypoxia-inducible factor 1 (HIF-1). HIF-1 facilitates quiescence maintenance and regulates differentiation by manipulating HSCs metabolism, being thus an appealing research target. Therefore, we examine the aberrant HIF-1 stabilization in BMs from MDS patients and controls (CTRLs). Using a nitroimidazole-indocyanine conjugate, we show that HIF-1 aberrant expression and transcription activity is oxygen independent, establishing the phenomenon of pseudohypoxia in MDS BM. Next, we examine mitochondrial quality and quantity along with levels of autophagy in the differentiating myeloid lineage isolated from fresh BM MDS and CTRL aspirates given that both phenomena are HIF-1 dependent. We show that the mitophagy of abnormal mitochondria and autophagic death are prominently featured in the MDS myeloid lineage, their severity increasing with intra-BM blast counts. Finally, we use in vitro cultured CD34+ HSCs isolated from fresh human BM aspirates to manipulate HIF-1 expression and examine its potential as a therapeutic target. We find that despite being cultured under 21% FiO2, HIF-1 remained aberrantly stable in all MDS cultures. Inhibition of the HIF-1α subunit had a variable beneficial effect in all <5%-intra-BM blasts-MDS, while it had no effect in CTRLs or in ≥5%-intra-BM blasts-MDS that uniformly died within 3 days of culture. We conclude that HIF-1 and pseudohypoxia are prominently featured in MDS pathobiology, and their manipulation has some potential in the therapeutics of benign MDS.

Different methylation signatures at diagnosis in patients with high-risk myelodysplastic syndromes and secondary acute myeloid leukemia predict azacitidine response and longer survival.

BACKGROUND: Epigenetic therapy, using hypomethylating agents (HMA), is known to be effective in the treatment of high-risk myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) patients who are not suitable for intensive chemotherapy and/or allogeneic stem cell transplantation. However, response rates to HMA are low and there is an unmet need in finding prognostic and predictive biomarkers of treatment response and overall survival. We performed global methylation analysis of 75 patients with high-risk MDS and secondary AML who were included in CETLAM SMD-09 protocol, in which patients received HMA or intensive treatment according to age, comorbidities and cytogenetic. RESULTS: Unsupervised analysis of global methylation pattern at diagnosis did not allow patients to be differentiated according to the cytological subtype, cytogenetic groups, treatment response or patient outcome. However, after a supervised analysis we found a methylation signature defined by 200 probes, which allowed differentiating between patients responding and non-responding to azacitidine (AZA) treatment and a different methylation pattern also defined by 200 probes that allowed to differentiate patients according to their survival. On studying follow-up samples, we confirmed that AZA decreases global DNA methylation, but in our cohort the degree of methylation decrease did not correlate with the type of response. The methylation signature detected at diagnosis was not useful in treated samples to distinguish patients who were going to relapse or progress. CONCLUSIONS: Our findings suggest that in a subset of specific CpGs, altered DNA methylation patterns at diagnosis may be useful as a biomarker for predicting AZA response and survival.

Severe ineffective erythropoiesis discriminates prognosis in myelodysplastic syndromes: analysis based on 776 patients from a single centre.

The underlying mechanisms and clinical significance of ineffective erythropoiesis in myelodysplastic syndromes (MDS) remain to be fully defined. We conducted the ex vivo erythroid differentiation of megakaryocytic-erythroid progenitors (MEPs) from MDS patients and discovered that patient-derived erythroblasts exhibit precocity and premature aging phenotypes, partially by inducing the pro-aging genes, like ERCC1. Absolute reticulocyte count (ARC) was chosen as a biomarker to evaluate the severity of ineffective erythropoiesis in 776 MDS patients. We found that patients with severe ineffective erythropoiesis displaying lower ARC (<20 × 109/L), were more likely to harbor complex karyotypes and high-risk somatic mutations (p < 0.05). Lower ARCs are associated with shorter overall survival (OS) in univariate analysis (p < 0.001) and remain significant in multivariable analysis. Regardless of patients of lower-risk who received immunosuppressive therapy or higher-risk who received decitabine treatment, patients with lower ARC had shorter OS (p < 0.001). Whereas no difference in OS was found between patients receiving allo-hematopoietic stem cell transplantations (Allo-HSCT) (p = 0.525). Our study revealed that ineffective erythropoiesis in MDS may be partially caused by premature aging and apoptosis during erythroid differentiation. MDS patients with severe ineffective erythropoiesis have significant shorter OS treated with immunosuppressive or hypo-methylating agents, but may benefit from Allo-HSCT.

Prognostic Markers of Myelodysplastic Syndromes.

Myelodysplastic syndrome (MDS) is a clonal disease characterized by multilineage dysplasia, peripheral blood cytopenias, and a high risk of transformation to acute myeloid leukemia. In theory, from clonal hematopoiesis of indeterminate potential to hematologic malignancies, there is a complex interplay between genetic and epigenetic factors, including miRNA. In practice, karyotype analysis assigns patients to different prognostic groups, and mutations are often associated with a particular disease phenotype. Among myeloproliferative disorders, secondary MDS is a group of special entities with a typical spectrum of genetic mutations and cytogenetic rearrangements resembling those in de novo MDS. This overview analyzes the present prognostic systems of MDS and the most recent efforts in the search for genetic and epigenetic markers for the diagnosis and prognosis of MDS.

Hematopoietic stem and progenitor cell-restricted Cdx2 expression induces transformation to myelodysplasia and acute leukemia.

The caudal-related homeobox transcription factor CDX2 is expressed in leukemic cells but not during normal blood formation. Retroviral overexpression of Cdx2 induces AML in mice, however the developmental stage at which CDX2 exerts its effect is unknown. We developed a conditionally inducible Cdx2 mouse model to determine the effects of in vivo, inducible Cdx2 expression in hematopoietic stem and progenitor cells (HSPCs). Cdx2-transgenic mice develop myelodysplastic syndrome with progression to acute leukemia associated with acquisition of additional driver mutations. Cdx2-expressing HSPCs demonstrate enrichment of hematopoietic-specific enhancers associated with pro-differentiation transcription factors. Furthermore, treatment of Cdx2 AML with azacitidine decreases leukemic burden. Extended scheduling of low-dose azacitidine shows greater efficacy in comparison to intermittent higher-dose azacitidine, linked to more specific epigenetic modulation. Conditional Cdx2 expression in HSPCs is an inducible model of de novo leukemic transformation and can be used to optimize treatment in high-risk AML.

Integrated Analysis of Long Non-Coding RNA and mRNA Expression Profile in Myelodysplastic Syndromes.

BACKGROUND: Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid malignancies. The incidence of MDS is gradually increasing, but the pathogenesis is still not very clear. Studies have shown that long non-coding RNAs (lncRNAs) play a critical role in both oncogenic and tumor-suppressive pathways. However, the function of lncRNAs in MDS is still unknown. The purpose of this study was to investigate the expression profiles and biological function of the aberrantly expressed lncRNAs and mRNAs in MDS. METHODS: We downloaded two data sets (GSE4619 and GSE19429) from the Gene Expression Omnibus database and obtained differentially expressed (DE) lncRNAs and DE-mRNAs between MDS cases and healthy controls. Then we performed systematic bioinformatics analysis to know the biological function of DE-lncRNAs and DE-mRNAs in MDS. RESULTS: We identified 40 DE-lncRNAs and 643 DE-mRNAs between MDS cases and healthy controls. Gene Ontology (GO) and pathway analysis revealed that DE-lncRNAs and DE-mRNAs were mainly involved in necroptosis, apoptosis, immunodeficiency, p53 and FoxO signaling pathways. LncRNA-mRNA co-expression and lncRNA functional similarity network showed that twelve down-regulated lncRNAs co-regulated the same target gene and they were similar in function. CONCLUSIONS: The comprehensive analysis of lncRNA and mRNA is helpful in understanding the pathogenesis of MDS, and the synergistically down-regulated lncRNAs may contribute to the development of new diagnostic and therapeutic strategies.

The IPSS-R more accurately captures fatigue severity of newly diagnosed patients with myelodysplastic syndromes compared with the IPSS index.

We aimed to compare fatigue of newly diagnosed patients with myelodysplastic syndromes (MDS) with that of the general population (GP). We also investigated the ability of the IPSS and IPSS-R to capture severity of patient-reported fatigue at diagnostic workup. A sample of 927 newly diagnosed patients with MDS was consecutively enrolled in a large international observational study and all patients completed the FACIT-Fatigue questionnaire at baseline. Fatigue was compared with that of the GP (N = 1075) and a 3-point difference in mean scores was considered as clinically meaningful. Fatigue of MDS patients was on average 4.6 points below the mean of the GP (95% CI, -5.9 to -3.2, p < 0.001), reflecting clinically meaningful worse fatigue. Unlike the IPSS, the IPSS-R identified clearly distinct subgroups with regard to burden of fatigue. Mean scores differences compared with GP ranged from nonclinically relevant for very low risk (Δ = -1.8, 95% CI, -4.0 to 0.5, p = 0.119) to large clinically meaningful differences for very high-risk IPSS-R patients (Δ = -8.2, 95% CI, -10.3 to -6.2, p < 0.001). At diagnostic workup, fatigue of MDS is clinically meaningful worse than that reported by the GP. Compared with the IPSS classification, the IPSS-R provides a better stratification of patients with regard to fatigue severity.

Profiling myelodysplastic syndromes by mass cytometry demonstrates abnormal progenitor cell phenotype and differentiation.

BACKGROUND: We sought to enhance the cytometric analysis of myelodysplastic syndromes (MDS) by performing a pilot study of a single cell mass cytometry (MCM) assay to more comprehensively analyze patterns of surface marker expression in patients with MDS. METHODS: Twenty-three MDS and five healthy donor bone marrow samples were studied using a 34-parameter mass cytometry panel utilizing barcoding and internal reference standards. The resulting data were analyzed by both traditional gating and high-dimensional clustering. RESULTS: This high-dimensional assay provided three major benefits relative to traditional cytometry approaches: First, MCM enabled detection of aberrant surface maker at high resolution, detecting aberrancies in 27/31 surface markers, encompassing almost every previously reported MDS surface marker aberrancy. Additionally, three previously unrecognized aberrancies in MDS were detected in multiple samples at least one developmental stage: increased CD321 and CD99; and decreased CD47. Second, analysis of the stem and progenitor cell compartment (HSPCs), demonstrated aberrant expression in 21 of the 23 MDS samples, which were not detected in three samples from patients with idiopathic cytopenia of undetermined significance. These immunophenotypically abnormal HSPCs were also the single most significant distinguishing feature between clinical risk groups. Third, unsupervised clustering of high-parameter MCM data allowed identification of abnormal differentiation patterns associated with immunophenotypically aberrant myeloid cells similar to myeloid derived suppressor cells. CONCLUSIONS: These results demonstrate that high-parameter cytometry methods that enable simultaneous analysis of all bone marrow cell types could enhance the diagnostic utility of immunophenotypic analysis in MDS.

Relationship between Low Pretreatment Geriatric Nutritional Risk Index and Poor Tolerability of Azacitidine in Patients with Myelodysplastic Syndromes.

BACKGROUND: Predicting tolerability and treatment-related risks associated with azacitidine (AZA) in patients with myelodysplastic syndromes (MDS) before the initiation of therapy is required for appropriate treatment. Thus, in this study, the nutritional status of patients with MDS prior to AZA treatment was evaluated using the geriatric nutritional risk index (GNRI). Tolerability and overall survival (OS) after AZA initiation were also investigated. METHODS: This was a single-center retrospective observational study. A total of 59 patients with MDS treated with AZA were assessed using GNRI, and a comparison of undernourished (GNRI <92, n = 27) and non-undernourished (GNRI ≥92, n = 32) patients was performed. RESULTS: The undernourished group had a significant reduction in the number of patients that successfully completed 4 cycles of AZA treatment compared with the non-undernourished group (undernourished group, 11/27 patients, 40.7% vs. non-undernourished group, 24/32 patients, 75.0%; p = 0.009). Factors associated with the difference included karyotype and GNRI. There was also a significant increase in the rate of infectious complications in the undernourished group compared with the non-undernourished group (undernourished group, 33/60 cycles, 55.0% vs. non-undernourished group, 31/92 cycles, 33.7%; p = 0.012). Lastly, a significant reduction in OS was observed in the undernourished group compared with the non-undernourished group (undernourished group, 11.5 months; 95% CI, 5.2-16.7 vs. non-undernourished group, 21.9 months; 95% CI, 13.8-24.0; p = 0.026). Factors associated with OS included both the revised International Prognostic Scoring System (IPSS-R) and GNRI. CONCLUSIONS: These results indicate that predicting treatment completion and adverse events in patients with MDS prior to AZA treatment is important. This study suggests GNRI may be a valuable nutritional assessment tool for determining tolerability and OS of AZA treatment.

Assessing clonal haematopoiesis: clinical burdens and benefits of diagnosing myelodysplastic syndrome precursor states.

Diagnosing, surveilling, and understanding the biological consequences of clonal haematopoiesis poses a clinical challenge for both patients and clinicians. The relationship between peripheral blood cytopenias and myeloid neoplasms-such as myelodysplastic syndrome-is an area of active research, and understanding of clonal haematopoiesis has developed markedly on the basis of findings concerning somatic mutations in genes known to be associated with myelodysplastic syndrome. These findings have raised the conundrum of how to appropriately define and follow myelodysplastic syndrome precursor states, such as clonal haematopoiesis of indeterminate potential (CHIP) and clonal cytopenias of undetermined significance (CCUS). Identifying these conditions could allow earlier diagnosis of myelodysplastic syndrome, modify surveillance for myelodysplastic syndrome, and possibly guide therapies, but this information also comes at a cost to patients that might or might not be justified by our present understanding of clonal haematopoiesis. When faced with a diagnosis of clonal haematopoiesis, some patients and providers might be content to let the events unfold naturally, whereas others may insist on intense follow-up and early interventions. This Viewpoint assesses recent developments in clonal haematopoiesis and the related implications for affected patients and their providers.

4-Amino-2-trifluoromethyl-phenyl retinate induced differentiation of human myelodysplastic syndromes SKM-1 cell lines by up-regulating DDX23.

Myelodysplastic syndrome (MDS) is a heterogeneously cloned hematopoietic stem cell malignancy with a high risk of developing acute myeloid leukemia (AML). 4-amino-2-trifluoromethyl-phenyl resinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative designed in our group, was proved to be a tumor inhibitor in diverse types of cancer cells in vitro. However, little has been known about the effects of ATPR on MDS. To analyze if and to what extent it's anti-tumor activity on MDS, we performed CCK-8, Flow Cytometry, Wright-Giemsa staining, qRT-PCR, and Western blot to analyze the SKM-1 cells state after ATPR treatment in multiplex detection angles. As expected, our results proved that ATPR could effectively induce cell differentiation and reduce cell proliferation of SKM-1 cell lines. Subsequently, to further analyze the potential mechanisms, we applied Label-free proteomic techniques to discover relevant protein that may be involved. Most notably, a series of factors related to RNA behavioral regulation were changed. Among them, we demonstrated that DEAD-box RNA helicase DDX23 was abnormally ablated in MDS patients and could be restored after ATPR treatment in vitro. Besides, our results suggested that ATPR-induced SKM-1 cell maturation was counteracted when knockdown DDX23, underscoring that DDX23 might be involved. In conclusion, we confirmed that ATPR could induce SKM-1 cells differentiation and its positive influence of DDX23 may provide a new idea to relieve MDS.