Integrating the "Immunome" in the Stratification of Myelodysplastic Syndromes and Future Clinical Trial Design

The immunoregulatory role of monocytes and thrombomodulin in myelodysplastic neoplasms

Myelodysplastic neoplasms (MDS) are clonal disorders of the myeloid lineage leading to peripheral blood cytopenias. Dysregulation of innate immunity is hypothesized to be a potent driver of MDS. A recent study revealed increased thrombomodulin (TM) expression on classical monocytes in MDS, which was associated with prolonged survival. TM is a receptor with immunoregulatory capacities, however, its exact role in MDS development remains to be elucidated. In this review we focus on normal monocyte biology and report on the involvement of monocytes in myeloid disease entities with a special focus on MDS. Furthermore, we delve into the current knowledge on TM and its function in monocytes in health and disease and explore the role of TM-expressing monocytes as driver, supporter or epiphenomenon in the MDS bone marrow environment.

Immune-monitoring of myelodysplastic neoplasms: Recommendations from the i4MDS consortium

Advancements in comprehending myelodysplastic neoplasms (MDS) have unfolded significantly in recent years, elucidating a myriad of cellular and molecular underpinnings integral to disease progression. While molecular inclusions into prognostic models have substantively advanced risk stratification, recent revelations have emphasized the pivotal role of immune dysregulation within the bone marrow milieu during MDS evolution. Nonetheless, immunotherapy for MDS has not experienced breakthroughs seen in other malignancies, partly attributable to the absence of an immune classification that could stratify patients toward optimally targeted immunotherapeutic approaches. A pivotal obstacle to establishing "immune classes" among MDS patients is the absence of validated accepted immune panels suitable for routine application in clinical laboratories. In response, we formed International Integrative Innovative Immunology for MDS (i4MDS), a consortium of multidisciplinary experts, and created the following recommendations for standardized methodologies to monitor immune responses in MDS. A central goal of i4MDS is the development of an immune score that could be incorporated into current clinical risk stratification models. This position paper first consolidates current knowledge on MDS immunology. Subsequently, in collaboration with clinical and laboratory specialists, we introduce flow cytometry panels and cytokine assays, meticulously devised for clinical laboratories, aiming to monitor the immune status of MDS patients, evaluating both immune fitness and identifying potential immune "risk factors." By amalgamating this immunological characterization data and molecular data, we aim to enhance patient stratification, identify predictive markers for treatment responsiveness, and accelerate the development of systems immunology tools and innovative immunotherapies.

Role of the STING pathway in myeloid neoplasms: a prospero-registered systematic review of principal hurdles of STING on the road to the clinical practice

Myeloid neoplasms are a group of bone marrow diseases distinguished by disruptions in the molecular pathways that regulate the balance between hematopoietic stem cell (HSC) self-renewal and the generation of specialized cells. Cytokines and chemokines, two important components of the inflammatory process, also influence hematological differentiation. In this scenario, immunological dysregulation plays a pivotal role in the pathogenesis of bone marrow neoplasms. The STING pathway recognizes DNA fragments in the cell cytoplasm and triggers an immune response by type I interferons. The role of STING in cancer has not yet been established; however, both actions, as an oncogene or tumor suppressor, have been documented in other types of cancer. Therefore, we performed a systematic review (registered in PROSPERO database #CRD42023407512) to discuss the role of STING pathway in the advancement of pathogenesis and/or prognosis for different myeloid neoplasms. In brief, scientific evidence supports investigations that primarily use cell lines from myeloid neoplasms, such as leukemia. More high-quality research and clinical trials are needed to understand the role of the STING pathway in the pathology of hematological malignancies. Finally, the STING pathway suggests being a promising therapeutic molecular target, particularly when combined with current drug therapies.

From Histiocytoid Sweet Syndrome to Myelodysplasia Cutis: History and Perspectives

In 2005, a new histologic variant of Sweet syndrome (SS) has been described and termed histiocytoid SS (HSS). Clinically, patients had a typical SS, but on skin biopsy, the infiltrates were composed of immature nonblast myeloid cells. Nearly 50% of patients with HSS have myelodysplastic syndrome (MDS). HSS may be the first manifestation leading to the diagnosis of MDS. In 2015, a new category of myeloid dermatosis has been proposed, called myelodysplasia cutis, describing the specific skin infiltration by myelodysplastic cells in patients with MDS.

Infectious Complications in Patients with Myelodysplastic Syndromes: A Report from the Düsseldorf MDS Registry

Despite notable advancements in infection prevention and treatment, individuals with hematologic malignancies still face the persistent threat of frequent and life-threatening complications. Those undergoing chemotherapy or other disease-modifying therapies are particularly vulnerable to developing infectious complications, increasing the risk of mortality. Myelodysplastic syndromes (MDS) predominantly affect the elderly, with the incidence rising with age and peaking at around 70 years. Patients with MDS commonly present with unexplained low blood-cell counts, primarily anemia, and often experience varying degrees of neutropenia as the disease progresses. In our subsequent retrospective study involving 1593 patients from the Düsseldorf MDS Registry, we aimed at outlining the incidence of infections in MDS patients and identifying factors contributing to heightened susceptibility to infectious complications in this population.

Discovery of U2AF1 neoantigens in myeloid neoplasms

BACKGROUND

Myelodysplastic syndromes (MDS) arise from somatic mutations acquired in hematopoietic stem and progenitor cells, causing cytopenias and predisposing to transformation into secondary acute myeloid leukemia (sAML). Recurrent mutations in spliceosome genes, including U2AF1, are attractive therapeutic targets as they are prevalent in MDS and sAML, arise early in neoplastic cells, and are generally absent from normal cells, including normal hematopoietic cells. MDS and sAML are susceptible to T cell-mediated killing, and thus engineered T-cell immunotherapies hold promise for their treatment. We hypothesized that targeting spliceosome mutation-derived neoantigens with transgenic T-cell receptor (TCR) T cells would selectively eradicate malignant cells in MDS and sAML.

METHODS

We identified candidate neoantigen epitopes from recurrent protein-coding mutations in the spliceosome genes SRSF2 and U2AF1 using a multistep in silico process. Candidate epitopes predicted to bind human leukocyte antigen (HLA) class I, be processed and presented from the parent protein, and not to be subject to tolerance then underwent in vitro immunogenicity screening. CD8+ T cells recognizing immunogenic neoantigen epitopes were evaluated in in vitro assays to assess functional avidity, confirm the predicted HLA restriction, the potential for recognition of similar peptides, and the ability to kill neoplastic cells in an antigen-specific manner. Neoantigen-specific TCR were sequenced, cloned into lentiviral vectors, and transduced into third-party T cells after knock-out of endogenous TCR, then tested in vitro for specificity and ability to kill neoplastic myeloid cells presenting the neoantigen. The efficacy of neoantigen-specific T cells was evaluated in vivo in a murine cell line-derived xenograft model.

RESULTS

We identified two neoantigens created from a recurrent mutation in U2AF1, isolated CD8+ T cells specific for the neoantigens, and demonstrated that transferring their TCR to third-party CD8+ T cells is feasible and confers specificity for the U2AF1 neoantigens. Finally, we showed that these neoantigen-specific TCR-T cells do not recognize normal hematopoietic cells but efficiently kill malignant myeloid cells bearing the specific U2AF1 mutation, including primary cells, in vitro and in vivo.

CONCLUSIONS

These data serve as proof-of-concept for developing precision medicine approaches that use neoantigen-directed T-cell receptor-transduced T cells to treat MDS and sAML.

Diagnostic and prognostic value of ferroptosis-related genes in patients with Myelodysplastic neoplasms

This study delves into the emerging role of ferroptosis in Myelodysplastic Neoplasms (MDS) and aims to identify a prognostic ferroptosis-related gene signature for MDS. Utilizing RNA-seq data and clinical information from the Gene Expression Omnibus database, the researchers extracted ferroptosis-related genes from the FerrDb website and conducted differential expression analysis using the 'limma' package in R. Hub ferroptosis-related genes in MDS were screened using the "RandomForest" and "carat" R packages. Kaplan -Meier and Cox regression analyses were employed to assess the prognostic role of three identified hub genes (BNIP3, MDM2, and RRM2). Receiver operator characteristic curve analysis confirmed the diagnostic efficacy of these genes. The study delved further into immune infiltration correlations, ncRNA-transcription factor coregulatory network analysis, and the identification of potential therapeutic drugs targeting hub ferroptosis-related genes in MDS. The researchers constructed a 3-gene signature-based risk score using datasets GSE58831 and GSE19429, demonstrating high accuracy (AUC > 0.75) in both datasets for survival prediction in MDS. A nomogram analysis reinforced the prognostic value of the risk-scoring model. Immunological analysis revealed an association between the risk score and immune infiltration. Quantitative reverse transcription polymerase chain reaction (qPCR) data indicated significant expression differences in MDM2, RRM2, and BNIP3 between MDS and healthy bone marrow samples. Notably, MDM2 and RRM2 showed decreased expression, while BNIP3 exhibited increased expression in MDS samples. This comprehensive study concludes that BNIP3, MDM2, and RRM2 hold diagnostic and prognostic significance in MDS and provide valuable insights into immune cell landscapes and potential therapeutic avenues for this condition.

Subclones with variants of uncertain clinical significance might contribute to ineffective hemopoiesis and leukemia predisposition

BACKGROUND

Splicing modifications, genomic instability, and hypomethylation are central mechanisms promoting myelodysplasia and acute myeloid leukemia (AML). In this real-life retrospective study, to elucidate pathophysiology of clonal hemopoiesis in hematological malignancies, we investigated clinical significance of mutations in leukemia-related genes of known pathogenetic significance and of variants of uncertain clinical significance (VUS) in a cohort of patients with MDS and AML.

METHODS

A total of 59 consecutive subjects diagnosed with MDS, 48 with AML, and 17 with clonal cytopenia with unknown significance were screened for somatic mutations in AML-related genes by next-generation sequencing.

RESULTS

We showed that TET2, SETBP1, ASXL1, EZH2, RUNX1, SRSF2, DNMT3A, and IDH1/2 were commonly mutated. MDS patients also showed a high genetic complexity, especially for SETBP1. Moreover, the presence of SETBP1 wild-type or two or more simultaneous VUS variants identified a subgroup of AML and MDS patients with better outcome, while the presence of single SETBP1 VUS variant was related to a worse prognosis, regardless TET2 mutational status.

CONCLUSIONS

In conclusions, we linked both pathogenic and VUS variants in AML-related genes to clonal hematopoiesis; therefore, we proposed to consider those variants as prognostic markers in leukemia and myelodysplasia. However, further studies in larger prospective cohorts are required to validate our results.

Emerging Insights into Molecular Mechanisms of Inflammation in Myelodysplastic Syndromes

Inflammation impacts human hematopoiesis across physiologic and pathologic conditions, as signals derived from the bone marrow microenvironment, such as pro-inflammatory cytokines and chemokines, have been shown to alter hematopoietic stem cell (HSCs) homeostasis. Dysregulated inflammation can skew HSC fate-related decisions, leading to aberrant hematopoiesis and potentially contributing to the pathogenesis of hematological disorders such as myelodysplastic syndromes (MDS). Recently, emerging studies have used single-cell sequencing and muti-omic approaches to investigate HSC cellular heterogeneity and gene expression in normal hematopoiesis as well as in myeloid malignancies. This review summarizes recent reports mechanistically dissecting the role of inflammatory signaling and innate immune response activation due to MDS progression. Furthermore, we highlight the growing importance of using multi-omic techniques, such as single-cell profiling and deconvolution methods, to unravel MDSs' heterogeneity. These approaches have provided valuable insights into the patterns of clonal evolution that drive MDS progression and have elucidated the impact of inflammation on the composition of the bone marrow immune microenvironment in MDS.

Activation of distinct inflammatory pathways in subgroups of LR-MDS

Aberrant innate immune signaling has been identified as a potential key driver of the complex pathophysiology of myelodysplastic neoplasms (MDS). This study of a large, clinically and genetically well-characterized cohort of treatment-naïve MDS patients confirms intrinsic activation of inflammatory pathways in general mediated by caspase-1, interleukin (IL)-1β and IL-18 in low-risk (LR)-MDS bone marrow and reveals a previously unrecognized heterogeneity of inflammation between genetically defined LR-MDS subgroups. Principal component analysis resolved two LR-MDS phenotypes with low (cluster 1) and high (cluster 2) levels of IL1B gene expression, respectively. Cluster 1 contained 14/17 SF3B1-mutated cases, while cluster 2 contained 8/8 del(5q) cases. Targeted gene expression analysis of sorted cell populations showed that the majority of the inflammasome-related genes, including IL1B, were primarily expressed in the monocyte compartment, consistent with a dominant role in determining the inflammatory bone marrow environment. However, the highest levels of IL18 expression were found in hematopoietic stem and progenitor cells (HSPCs). The colony forming activity of healthy donor HSPCs exposed to monocytes from LR-MDS was increased by the IL-1β-neutralizing antibody canakinumab. This work reveals distinct inflammatory profiles in LR-MDS that are of likely relevance to the personalization of emerging anti-inflammatory therapies.

Management of Patients with Lower-Risk Myelodysplastic Neoplasms (MDS)

Myelodysplastic neoplasms (MDS) are a heterogenous group of clonal hematologic disorders characterized by morphologic dysplasia, ineffective hematopoiesis, and cytopenia. In the past year, the classification of MDS has been updated in the 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours and the International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemia with incorporation of morphologic, clinical, and genomic data. Furthermore, the more comprehensive International Prognostic Scoring System-Molecular (IPSS-M) allows for improved risk stratification and prognostication. These three developments allow for more tailored therapeutic decision-making in view of the expanding treatment options in MDS. For patients with lower risk MDS, treatment is aimed at improving cytopenias, usually anemia. The recent approval of luspatercept and decitabine/cedazuridine have added on to the current armamentarium of erythropoietic stimulating agents and lenalidomide (for MDS with isolated deletion 5q). Several newer agents are being evaluated in phase 3 clinical trials for this group of patients, such as imetelstat and oral azacitidine. This review provides a summary of the classification systems, the prognostic scores and clinical management of patients with lower risk MDS.

A multimodal analysis of genomic and RNA splicing features in myeloid malignancies

RNA splicing dysfunctions are more widespread than what is believed by only estimating the effects resulting by splicing factor mutations (SF^MT) in myeloid neoplasia (MN). The genetic complexity of MN is amenable to machine learning (ML) strategies. We applied an integrative ML approach to identify co-varying features by combining genomic lesions (mutations, deletions, and copy number), exon-inclusion ratio as measure of RNA splicing (percent spliced in, PSI), and gene expression (GE) of 1,258 MN and 63 normal controls. We identified 15 clusters based on mutations, GE, and PSI. Different PSI levels were present at various extents regardless of SF^MT suggesting that changes in RNA splicing were not strictly related to SF^MT. Combination of PSI and GE further distinguished the features and identified PSI similarities and differences, common pathways, and expression signatures across clusters. Thus, multimodal features can resolve the complex architecture of MN and help identifying convergent molecular and transcriptomic pathways amenable to therapies.

Multiparameter flow cytometry in the evaluation of myelodysplasia: Analytical issues: Recommendations from the European LeukemiaNet/International Myelodysplastic Syndrome Flow Cytometry Working Group

Multiparameter flow cytometry (MFC) is one of the essential ancillary methods in bone marrow (BM) investigation of patients with cytopenia and suspected myelodysplastic syndrome (MDS). MFC can also be applied in the follow-up of MDS patients undergoing treatment. This document summarizes recommendations from the International/European Leukemia Net Working Group for Flow Cytometry in Myelodysplastic Syndromes (ELN iMDS Flow) on the analytical issues in MFC for the diagnostic work-up of MDS. Recommendations for the analysis of several BM cell subsets such as myeloid precursors, maturing granulocytic and monocytic components and erythropoiesis are given. A core set of 17 markers identified as independently related to a cytomorphologic diagnosis of myelodysplasia is suggested as mandatory for MFC evaluation of BM in a patient with cytopenia. A myeloid precursor cell (CD34⁺ CD19^- ) count >3% should be considered immunophenotypically indicative of myelodysplasia. However, MFC results should always be evaluated as part of an integrated hematopathology work-up. Looking forward, several machine-learning-based analytical tools of interest should be applied in parallel to conventional analytical methods to investigate their usefulness in integrated diagnostics, risk stratification, and potentially even in the evaluation of response to therapy, based on MFC data. In addition, compiling large uniform datasets is desirable, as most of the machine-learning-based methods tend to perform better with larger numbers of investigated samples, especially in such a heterogeneous disease as MDS.

Clinical application of flow cytometry in patients with unexplained cytopenia and suspected myelodysplastic syndrome: A report of the European LeukemiaNet International MDS-Flow Cytometry Working Group

This article discusses the rationale for inclusion of flow cytometry (FCM) in the diagnostic investigation and evaluation of cytopenias of uncertain origin and suspected myelodysplastic syndromes (MDS) by the European LeukemiaNet international MDS Flow Working Group (ELN iMDS Flow WG). The WHO 2016 classification recognizes that FCM contributes to the diagnosis of MDS and may be useful for prognostication, prediction, and evaluation of response to therapy and follow-up of MDS patients.

A low carbohydrate diet high in fish oil and soy protein delays inflammation, hematopoietic stem cell depletion, and mortality in miR-146a knock-out mice

Since our previous studies found a low carbohydrate (CHO) diet containing soy protein and fish oil (15%Amylose/Soy/FO) significantly reduced lung and breast cancer in mice we asked herein if this low CHO diet could also delay the onset of myeloid malignancies. To test this we employed a miR-146a knock-out (KO) mouse model and found the 15%Amylose/Soy/FO diet increased their median lifespan by 8.5 month, compared to these mice on a Western diet. This was associated with increased lymphocytes and reduced monocytes, granulocytes, blood glucose and insulin levels. Inflammatory cytokine/chemokine studies carried out with 6-month-old mice, before any signs of illness, revealed the 15%Amylose/Soy/FO diet significantly reduced pro-inflammatory cytokines. This low CHO diet also led to an increase in plasma β-hydroxybutyrate and in liver fatty acid synthase levels. This, together with higher liver carnitine palmitoyltransferase I levels suggested that the 15%Amylose/Soy/FO diet was causing a systemic metabolic shift from glucose to fatty acids as an energy source. Lastly, we found the 15%Amylose/Soy/FO diet resulted in significantly higher numbers of primitive hematopoietic stem cells (HSCs) in the bone marrow of 6-month-old mice than those fed a Western diet. Taken together, these results suggest a 15%Amylose/Soy/FO diet reduces chronic inflammation and increases fatty acid oxidation and that this, in turn, may prevent HSC proliferation and exhaustion, thereby delaying myeloid malignancy-induced death of miR-146a KO mice. We suggest a low CHO diet containing soy protein and fish oil could be beneficial in reducing the risk of myeloid malignancies in patients with low miR-146a levels.

Bone Marrow Immune Microenvironment in Myelodysplastic Syndromes

The BM, the major hematopoietic organ in humans, consists of a pleiomorphic environment of cellular, extracellular, and bioactive compounds with continuous and complex interactions between them, leading to the formation of mature blood cells found in the peripheral circulation. Systemic and local inflammation in the BM elicit stress hematopoiesis and drive hematopoietic stem cells (HSCs) out of their quiescent state, as part of a protective pathophysiologic process. However, sustained chronic inflammation impairs HSC function, favors mutagenesis, and predisposes the development of hematologic malignancies, such as myelodysplastic syndromes (MDS). Apart from intrinsic cellular mechanisms, various extrinsic factors of the BM immune microenvironment (IME) emerge as potential determinants of disease initiation and evolution. In MDS, the IME is reprogrammed, initially to prevent the development, but ultimately to support and provide a survival advantage to the dysplastic clone. Specific cellular elements, such as myeloid-derived suppressor cells (MDSCs) are recruited to support and enhance clonal expansion. The immune-mediated inhibition of normal hematopoiesis contributes to peripheral cytopenias of MDS patients, while immunosuppression in late-stage MDS enables immune evasion and disease progression towards acute myeloid leukemia (AML). In this review, we aim to elucidate the role of the mediators of immune response in the initial pathogenesis of MDS and the evolution of the disease.

Landscape of alterations in the checkpoint system in myelodysplastic syndrome and implications for prognosis

The emergence of novel immunotherapies for myelodysplastic syndrome (MDS) calls for a profound characterization of the "immunome" in the bone marrow (BM) and evaluation of prognostic impact of immunological changes. We performed a prospective study of 87 MDS patients who were referred to a tertiary hematological center and of 11 bone marrow donors who were not related to the study cohort. A flow cytometry panel with 48 markers including checkpoint ligands and receptors was used to study lymphoid and myeloid subpopulations in the bone marrow aspirates. The study found that both the healthy donors and the MDS patients have a high proportion of lymphocytes with PD-1 expression (41±18% and 58±25% respectively) and a high proportion of myeloid cells with PD-1L expression (31±23% and 12±7% respectively), indicating a potential physiological role of checkpoint systems in BM. At the same time, complex alterations including PD-1, CTLA-4, LAG-3 and TIM3 pathways accompanied by an increased level of T-reg and myeloid derived suppressor cell populations were identified in the BM of MDS patients. Cluster analysis showed independent prognostic significance of the checkpoint profile for overall survival (HR 1.90, 95%CI 1.01–3.56, p = 0.0471). TIM3-postive NK and CD8 effector cells along with the blast count were the key subpopulations for prognosis. An elevation of blasts in the bone marrow was associated with simultaneous expression of multiple checkpoints on myeloid cells.

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.

How Azanucleosides Affect Myeloid Cell Fate

The azanucleosides decitabine and azacytidine are used widely in the treatment of myeloid neoplasia and increasingly in the context of combination therapies. Although they were long regarded as being largely interchangeable in their function as hypomethylating agents, the azanucleosides actually have different mechanisms of action; decitabine interferes primarily with the methylation of DNA and azacytidine with that of RNA. Here, we examine the role of DNA methylation in the lineage commitment of stem cells during normal hematopoiesis and consider how mutations in epigenetic regulators such as DNMT3A and TET2 can lead to clonal expansion and subsequent neoplastic progression. We also consider why the efficacy of azanucleoside treatment is not limited to neoplasias carrying mutations in epigenetic regulators. Finally, we summarise recent data describing a role for azacytidine-sensitive RNA methylation in lineage commitment and in the cellular response to stress. By summarising and interpreting evidence for azanucleoside involvement in a range of cellular processes, our review is intended to illustrate the need to consider multiple modes of action in the design and stratification of future combination therapies.

Increased prescription rate of anti‐infective agents after diagnosis of myelodysplastic syndromes

The a priori risk for infections in patients with myelodysplastic syndromes (MDS) is unknown. This study examines prescription rates of anti‐infective agents in MDS patients before and after diagnosis, in both in‐ and outpatient settings, to provide information on infection management in clinical practice.

We performed a population‐based study using the HemoBase registry, containing data of all MDS patients diagnosed since 2005 in Friesland, the Netherlands. Community and hospital pharmacies provided prescription data from 1995 to 2020.

Data were obtained for 203 of 292 patients (70%). Patients received significantly more anti‐infective agents, predominantly antibacterials (70%), after diagnosis compared to before: 148.7 defined daily dose/1000 days (DID) (95% CI: 146.9–150.5) and 55.1 DID (95% CI: 54.5–55.8, p < 0.01), respectively, corresponding to median 23.5 and 7.6 treatment days/year. Higher‐risk (449.9 DID) and lower‐risk patients (129.1 DID) both received significantly more anti‐infective agents after diagnosis; comorbidities, neutropenia, and age did not show significant differences relative to prescription rates. Before diagnosis, 10% of patients had infection‐related hospital admissions versus 38% after diagnosis.

In conclusion, MDS patients received significantly more anti‐infective agents compared to before diagnosis. This is the first study that has quantified the prescription rate of anti‐infective agents within and beyond the clinical setting in MDS.

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.

New Frontiers in Monoclonal Antibodies for the Targeted Therapy of Acute Myeloid Leukemia and Myelodysplastic Syndromes

Acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) represent an unmet clinical need whose prognosis is still dismal. Alterations of immune response play a prominent role in AML/MDS pathogenesis, revealing novel options for immunotherapy. Among immune system regulators, CD47, immune checkpoints, and toll-like receptor 2 (TLR2) are major targets. Magrolimab antagonizes CD47, which is overexpressed by AML and MDS cells, thus inducing macrophage phagocytosis with clinical activity in AML/MDS. Sabatolimab, an inhibitor of T-cell immunoglobulin and mucin domain-containing protein 3 (TIM3), which disrupts its binding to galectin-9, has shown promising results in AML/MDS, enhancing the effector functions of lymphocytes and triggering tumor cell death. Several other surface molecules, namely CD33, CD123, CD45, and CD70, can be targeted with monoclonal antibodies (mAbs) that exert different mechanisms of action and include naked and conjugated antibodies, bispecific T-cell engagers, trispecific killer engagers, and fusion proteins linked to toxins. These novel mAbs are currently under investigation for use as monotherapy or in combination with hypomethylating agents, BCL2 inhibitors, and chemotherapy in various clinical trials at different phases of development. Here, we review the main molecular targets and modes of action of novel mAb-based immunotherapies, which can represent the future of AML and higher risk MDS treatment.

Microenvironmental Features Driving Immune Evasion in Myelodysplastic Syndromes and Acute Myeloid Leukemia

Bone marrow, besides the known functions of hematopoiesis, is an active organ of the immune system, functioning as a sanctuary for several mature immune cells. Moreover, evidence suggests that hematopoietic stem cells (the bone marrow’s functional unit) are capable of directly sensing and responding to an array of exogenous stimuli. This chronic immune stimulation is harmful to normal hematopoietic stem cells, while essential for the propagation of myeloid diseases, which show a dysregulated immune microenvironment. The bone marrow microenvironment in myelodysplastic syndromes (MDS) is characterized by chronic inflammatory activity and immune dysfunction, that drive excessive cellular death and through immune evasion assist in cancer cell expansion. Acute myeloid leukemia (AML) is another example of immune response failure, with features that augment immune evasion and suppression. In this review, we will outline some of the functions of the bone marrow with immunological significance and describe the alterations in the immune landscape of MDS and AML that drive disease progression.

Hostile Takeover: Tregs expand in IFN-γ-rich AML microenvironment

The unexpected higher level of IFN-γ in a subset of AML patients (IFN-γ high) up-regulates immunosuppressive genes in MSCs and expands Tregs through IDO1 overexpression. IDO1 and IFNG gene expression were positively correlated and required both leukemia cells and MSCs, as IFN-γ high cells were not able to induce Tregs alone.

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.

Inflammation and myeloid malignancy: Quenching the flame

Chronic inflammation with aging ("inflammaging") plays a prominent role in the pathogenesis of myeloid malignancies. Aberrant inflammatory activity impacts many different cells in the marrow, including normal blood and stromal marrow elements and leukemic cells, in unique and distinct ways. Inflammation can promote selective clonal expansion through differential immune-mediated suppression of normal hematopoietic cells and malignant clones. We review these complex roles, how they can be understood by separating cell-intrinsic from extrinsic effects, and how this informs future clinical trials.

Dysfunctional bone marrow endothelial progenitor cells are involved in patients with myelodysplastic syndromes

Background

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal disorders characterized by ineffective haematopoiesis and immune deregulation. Emerging evidence has shown the effect of bone marrow (BM) endothelial progenitor cells (EPCs) in regulating haematopoiesis and immune balance. However, the number and functions of BM EPCs in patients with different stages of MDS remain largely unknown.

Methods

Patients with MDS (N = 30), de novo acute myeloid leukaemia (AML) (N = 15), and healthy donors (HDs) (N = 15) were enrolled. MDS patients were divided into lower-risk MDS (N = 15) and higher-risk MDS (N = 15) groups according to the dichotomization of the Revised International Prognostic Scoring System. Flow cytometry was performed to analyse the number of BM EPCs. Tube formation and migration assays were performed to evaluate the functions of BM EPCs. In order to assess the gene expression profiles of BM EPCs, RNA sequencing (RNA-seq) were performed. BM EPC supporting abilities of haematopoietic stem cells (HSCs), leukaemia cells and T cells were assessed by in vitro coculture experiments.

Results

Increased but dysfunctional BM EPCs were found in MDS patients compared with HDs, especially in patients with higher-risk MDS. RNA-seq indicated the progressive change and differences of haematopoiesis- and immune-related pathways and genes in MDS BM EPCs. In vitro coculture experiments verified that BM EPCs from HDs, lower-risk MDS, and higher-risk MDS to AML exhibited a progressively decreased ability to support HSCs, manifested as elevated apoptosis rates and intracellular reactive oxygen species (ROS) levels and decreased colony-forming unit plating efficiencies of HSCs. Moreover, BM EPCs from higher-risk MDS patients demonstrated an increased ability to support leukaemia cells, characterized by increased proliferation, leukaemia colony-forming unit plating efficiencies, decreased apoptosis rates and apoptosis-related genes. Furthermore, BM EPCs induced T cell differentiation towards more immune-tolerant cells in higher-risk MDS patients in vitro. In addition, the levels of intracellular ROS and the apoptosis ratios were increased in BM EPCs from MDS patients, especially in higher-risk MDS patients, which may be therapeutic candidates for MDS patients.

Conclusion

Our results suggest that dysfunctional BM EPCs are involved in MDS patients, which indicates that improving haematopoiesis supporting ability and immuneregulation ability of BM EPCs may represent a promising therapeutic approach for MDS patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03354-2.

Single-Cell Technologies to Decipher the Immune Microenvironment in Myeloid Neoplasms: Perspectives and Opportunities

Myeloid neoplasms (MN) are heterogeneous clonal disorders arising from the expansion of hematopoietic stem and progenitor cells. In parallel with genetic and epigenetic dynamics, the immune system plays a critical role in modulating tumorigenesis, evolution and therapeutic resistance at the various stages of disease progression. Single-cell technologies represent powerful tools to assess the cellular composition of the complex tumor ecosystem and its immune environment, to dissect interactions between neoplastic and non-neoplastic components, and to decipher their functional heterogeneity and plasticity. In addition, recent progress in multi-omics approaches provide an unprecedented opportunity to study multiple molecular layers (DNA, RNA, proteins) at the level of single-cell or single cellular clones during disease evolution or in response to therapy. Applying single-cell technologies to MN holds the promise to uncover novel cell subsets or phenotypic states and highlight the connections between clonal evolution and immune escape, which is crucial to fully understand disease progression and therapeutic resistance. This review provides a perspective on the various opportunities and challenges in the field, focusing on key questions in MN research and discussing their translational value, particularly for the development of more efficient immunotherapies.

How low risk are low risk myelodysplastic syndromes?

INTRODUCTION

Risk stratification is crucial to the appropriate management of many diseases, but in patients with myelodysplastic syndromes (MDS), for whom expected survival can vary greatly, accurate disease prognostication is especially important. This is further supported by a relative lack of therapies in MDS, and thus we must prognosticate carefully and accurately. Currently, patients with MDS are often grouped into higher-risk (HR) versus lower-risk (LR) disease using clinical prognostic scoring systems, but these systems have limitations.

AREAS COVERED

The authors reviewed the literature on diagnostics, prognostics, therapeutics and outcomes in MDS. Factors such as disease etiology, specific clinical characteristics, or molecular genetic information not captured in the international prognostic scoring system revised IPSS-R can alter risk stratification, and identify a subset of LR-MDS patients who actually behave more like HR-MDS.

EXPERT OPINION

This review will describe the current identification and management of patients with LR MDS disease whose condition is likely to behave in a less favorable manner than predicted by the IPSS-R. The authors comment on clinical and molecular features which are believe to upstage a patient from lower to higher risk disease.

How predictive is the finding of clonal hematopoiesis for the development of myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML)?

Clonal hematopoiesis (CH) - a biological state in which one or a small number of hematopoietic stem or progenitor cells contribute disproportionately to blood cell production, usually as a result of somatic gene mutations in the stem cells - is often considered to be a precursor to myeloid neoplasia, especially myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). However, the majority of people with CH never develop an overt myeloid neoplasm, and CH can be a precursor to lymphoid cancers as well as myeloid neoplasms. In addition, CH increases all-cause mortality and augments the risk of several non-neoplastic medical conditions, including atherosclerotic cardiovascular disease. CH can arise during aging, or in the context of an inherited marrow failure syndrome, aplastic anemia, or hematopoietic cell transplantation. Risk factors for progression of CH to myeloid neoplasia include larger clone size; the presence of a TP53, IDH1/2, or splicing mutation; multiple mutations; and associated cytopenias or abnormal red blood cell indices. The receipt of genotoxic chemotherapy or radiation, which can promote clonal expansion of mutant clones at the expense of healthy progenitor cells, may result in therapy-related MDS/AML.

Differentiation therapy for myeloid malignancies: beyond cytotoxicity

Blocked cellular differentiation is a central pathologic feature of the myeloid malignancies, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Treatment regimens promoting differentiation have resulted in incredible cure rates in certain AML subtypes, such as acute promyelocytic leukemia. Over the past several years, we have seen many new therapies for MDS/AML enter clinical practice, including epigenetic therapies (e.g., 5-azacitidine), isocitrate dehydrogenase (IDH) inhibitors, fms-like kinase 3 (FLT3) inhibitors, and lenalidomide for deletion 5q (del5q) MDS. Despite not being developed with the intent of manipulating differentiation, induction of differentiation is a major mechanism by which several of these novel agents function. In this review, we examine the new therapeutic landscape for these diseases, focusing on the role of hematopoietic differentiation and the impact of inflammation and aging. We review how current therapies in MDS/AML promote differentiation as a part of their therapeutic effect, and the cellular mechanisms by which this occurs. We then outline potential novel avenues to achieve differentiation in the myeloid malignancies for therapeutic purposes. This emerging body of knowledge about the importance of relieving differentiation blockade with anti-neoplastic therapies is important to understand how current novel agents function and may open avenues to developing new treatments that explicitly target cellular differentiation. Moving beyond cytotoxic agents has the potential to open new and unexpected avenues in the treatment of myeloid malignancies, hopefully providing more efficacy with reduced toxicity.

A CIBERSORTx-based immune cell scoring system could independently predict the prognosis of patients with myelodysplastic syndromes

Aside from cell intrinsic factors such as genetic alterations, immune dysregulation in the bone marrow (BM) microenvironment plays a role in the development and progression of myelodysplastic syndromes (MDS). However, the prognostic implications of various immune cells in patients with MDS remain unclear. We adopted CIBERSORTx to estimate the relative fractions of 22 subtypes of immune cells in the BM of 316 patients with MDS and correlated the results with clinical outcomes. A lower fraction of unpolarized M0 macrophages and higher fractions of M2 macrophages and eosinophils were significantly associated with inferior survival. An immune cell scoring system (ICSS) was constructed based on the proportion of these 3 immune cells in the BM. The ICSS high-risk patients had higher BM blast counts, higher frequencies of poor-risk cytogenetics, and more NPM1, TP53, and WT1 mutations than intermediate- and low-risk patients. The ICSS could stratify patients with MDS into 3 risk groups with distinct leukemia-free survival and overall survival among the total cohort and in the subgroups of patients with lower and higher disease risk based on the revised International Prognostic Scoring System (IPSS-R). The prognostic significance of ICSS was also validated in another independent cohort. Multivariable analysis revealed that ICSS independently predicted prognosis, regardless of age, IPSS-R, and mutation status. Bioinformatic analysis demonstrated a significant correlation between high-risk ICSS and nuclear factor κB signaling, oxidative stress, and leukemic stem cell signature pathways. Further studies investigating the mechanistic insight into the crosstalk between stem cells and immune cells are warranted.

Suprabasin: Role in human cancers and other diseases

Suprabasin (SBSN), a gene with unknown function located in q13 region of chromosome 19, was first found to be expressed in the basal layer of the stratified epithelium in mouse and human tissues and was thought to be a potential precursor of keratinized capsules. However, in recent years, significant progress has been made in the study of SBSN in a variety of human diseases. One common theme appears to be the effect of SBSN on tumor progression, such as invasion, metastasis and resistance. However, the function and mechanism of action of SBSN is still elusive. In this study, we reviewed the literature on SBSN in the PubMed database to identify the basic characteristics, biological functions, and roles of SBSN in cancer and other diseases. In particular, we focused on the potential mechanisms of SBSN activity, to improve our understanding of the complex function of this protein and provide a theoretical basis for further research on the role of SBSN in cancer and other diseases.

Immune signatures of bone marrow cells can independently predict prognosis in patients with myelodysplastic syndrome

Increasing evidence supports the role of the immune microenvironment and associated signalling in the pathogenesis of myelodysplastic syndromes (MDS). Nevertheless, the clinical relevancy of immune signals in patients with MDS remains elusive. To address this, we used single-sample gene-set enrichment analysis to score immune signatures of bone marrow (BM) samples from 176 patients with primary MDS. Enhanced signatures of 'immature dendritic cells' and 'natural killer cells with cluster of differentiation (CD)56^bright' were correlated with better overall survival (OS), whilst higher 'CD103⁺ signature' was associated with reduced survival. An MDS-Immune-Risk (MIR) scoring system was constructed based on the weighted sums derived from Cox regression analysis. High MIR scores were correlated with higher revised International Prognostic Scoring System (IPSS-R) scores and mutations in ASXL transcriptional regulator 1 (ASXL1), Runt-related transcription factor 1 (RUNX1), and tumour protein p53 (TP53). High-score patients had significantly inferior leukaemia-free survival (LFS) and OS than low-score patients. The prognostic significance of MIR scores for survival remained valid across IPSS-R subgroups and was validated in two independent cohorts. Multivariable analysis revealed that a higher MIR score was an independent adverse risk factor for LFS and OS. We further proposed a model with the combination of MIR score and gene mutations to be complementary to IPSS-R for the prognostication of LFS and OS of patients with MDS.

Myelodysplastic Syndromes in the Postgenomic Era and Future Perspectives for Precision Medicine

Simple Summary

With demographic ageing, improved cancer survivorship and increased diagnostic sensitivity, incident cases of patients with Myelodysplastic Syndromes (MDS) are continuously rising, leading to a relevant impact on health care resources. Disease heterogeneity and various comorbidities are challenges for the management of the generally elderly patients. Therefore, experienced physicians and multidisciplinary teams should be involved in the establishment of the correct diagnosis, risk-assessment and personalized treatment plan. Next-generation sequencing allows for early detection of clonal hematopoiesis and monitoring of clonal evolution, but also poses new challenges for its appropriate use. At present, allogeneic hematopoietic stem cell transplantation remains the only curative treatment option for a minority of fit MDS patients. All others receive palliative treatment and will eventually progress, having an unmet need for novel therapies. Targeting compounds are in prospect for precision medicine, however, abrogation of clonal evolution to acute myeloid leukemia remains actually out of reach.

Abstract

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders caused by sequential accumulation of somatic driver mutations in hematopoietic stem and progenitor cells (HSPCs). MDS is characterized by ineffective hematopoiesis with cytopenia, dysplasia, inflammation, and a variable risk of transformation into secondary acute myeloid leukemia. The advent of next-generation sequencing has revolutionized our understanding of the genetic basis of the disease. Nevertheless, the biology of clonal evolution remains poorly understood, and the stochastic genetic drift with sequential accumulation of genetic hits in HSPCs is individual, highly dynamic and hardly predictable. These continuously moving genetic targets pose substantial challenges for the implementation of precision medicine, which aims to maximize efficacy with minimal toxicity of treatments. In the current postgenomic era, allogeneic hematopoietic stem cell transplantation remains the only curative option for younger and fit MDS patients. For all unfit patients, regeneration of HSPCs stays out of reach and all available therapies remain palliative, which will eventually lead to refractoriness and progression. In this review, we summarize the recent advances in our understanding of MDS pathophysiology and its impact on diagnosis, risk-assessment and disease monitoring. Moreover, we present ongoing clinical trials with targeting compounds and highlight future perspectives for precision medicine.

Innate immune pathways and inflammation in hematopoietic aging, clonal hematopoiesis, and MDS

With a growing aged population, there is an imminent need to develop new therapeutic strategies to ameliorate disorders of hematopoietic aging, including clonal hematopoiesis and myelodysplastic syndrome (MDS). Cell-intrinsic dysregulation of innate immune- and inflammatory-related pathways as well as systemic inflammation have been implicated in hematopoietic defects associated with aging, clonal hematopoiesis, and MDS. Here, we review and discuss the role of dysregulated innate immune and inflammatory signaling that contribute to the competitive advantage and clonal dominance of preleukemic and MDS-derived hematopoietic cells. We also propose how emerging concepts will further reveal critical biology and novel therapeutic opportunities.

Development of luspatercept to treat ineffective erythropoiesis

Luspatercept (Reblozyl) was recently approved for treating patients with transfusion-dependent lower-risk myelodysplastic syndrome (MDS) with ring sideroblasts (RS) and/or SF3B1 mutation who were not eligible for erythropoiesis-stimulating agents (ESAs) or patients for whom those agents failed. Luspatercept acts as an activin receptor type IIB fusion protein ligand trap that targets the altered transforming growth factor beta pathway in MDS, which is associated with impaired terminal erythroid maturation. Treatment with luspatercept results in decreased SMAD signaling, which enables erythroid maturation by means of late-stage erythroblast differentiation and thus improves anemia. ESAs, the current standard first-line therapeutic option for anemic lower-risk patients with MDS, also improve red cell parameters mainly by expanding proliferation of early erythroid progenitor cells. However, erythropoietin (EPO) and its receptor (EPO-R) are also required for survival of late-stage definitive erythroid cells, and they play an essential role in promoting proliferation, survival, and appropriate timing of terminal maturation of primitive erythroid precursors. Thus, luspatercept joins the mechanism of ESAs in promoting erythroid maturation. Especially in the subgroup of MDS patients with RS, luspatercept showed high clinical activity for the treatment of anemia in the phase 2 (PACE-MDS) trial and subsequently in the phase 3 (MEDALIST) trial, which resulted in approval by both the US Food and Drug Administration and the European Medicines Agency in April 2020. Additional studies are needed to better understand the mechanism of action and pharmacodynamics of this novel agent in MDS.

Prognosis in Myelodysplastic Syndromes: The Clinical Challenge of Genomic Integration

Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic neoplasms characterized by ineffective hematopoiesis and myelodysplasia with a variable spectrum of clinical-biological features that can be used to build a prognostic estimation. This review summarizes the current most widely used prognostic scoring systems and gives a general view of the prognostic impact of somatic mutations in MDS patients.

Novel molecular regulators of breast cancer stem cell plasticity and heterogeneity

Tumors consist of heterogeneous cell populations, and tumor heterogeneity plays key roles in regulating tumorigenesis, metastasis, recurrence and resistance to anti-tumor therapies. More and more studies suggest that cancer stem cells (CSCs) promote tumorigenesis, metastasis, recurrence and drug resistance as well as are the major source for heterogeneity of cancer cells. CD24^-CD44⁺ and ALDH⁺ are the most common markers for breast cancer stem cells (BCSCs). Previous studies showed that different BCSC markers label different BCSC populations, indicating the heterogeneity of BCSCs. Therefore, defining the regulation mechanisms of heterogeneous BCSCs is essential for precisely targeting BCSCs and treating breast cancer. In this review, we summarized the novel regulators existed in BCSCs and their niches for BCSC heterogeneity which has been discovered in recent years, and discussed their regulation mechanisms and the latest corresponding cancer treatments, which will extend our understanding on BCSC heterogeneity and plasticity, and provide better prognosis prediction and more efficient novel therapeutic strategies for breast cancer.

ERVs-TLR3-IRF axis is linked to myelodysplastic syndrome pathogenesis

Toll-like receptors are mutated or overexpressed in up to 50% of patients with myelodysplastic syndrome (MDS). Endogenous retroviruses (ERV) trigger TLR3 leading to interferon regulatory genes (IRFs) activation. We evaluated if the ERVs-TLR3-IRF axis activation would be linked to MDS pathogenesis and we also conducted a detailed cancer analysis of the ERVs, TLR3 and IRFs gene expression in 30 cancer types using GEPIA database. Seventy-nine bone marrow samples from patients with MDS were evaluated for cytogenetics and quantitative real‑time PCR of TLR3, ERVK6, ERVW-1, ERV3-1, IRF3 and IRF7. Patients with dyserythropoiesis showed higher TLR3 (p = 0.035), ERVK6 (p = 0.001), ERVW1 (p = 0.045) and ERV3-1 (p = 0.016) expression than patients without dyserythropoiesis. Upregulation of Interferon Regulatory Factors, IRF3 and IRF7, was associated with poor prognostic markers in MDS such as > 10% of blasts (p = 0.003-IRF3; p = 0.009-IRF7), low platelets count (< 50.000/mm³) (p = 0.001-IRF3; p = 0.021-IRF7), transfusion dependence (p = 0.014-IRF3) and chromosomal abnormalities (p = 0.036-IRF7). We found strong correlations between ERVK6-ERVW1 (r = 0.800; r² = 0.640; p = 0.000), ERVW1-ERV3-1 (r = 0.715; r² = 0.511; p = 0.000), and IRF7-IRF3 (r = 0.567; r² = 0.321; p = 0.000) and moderate correlation between ERVK6-ERV3-1(r = 0.485; r² = 0.235; p = 0.000), ERVW1-IRF7 (r = 0.389; r² = 0.151; p = 0.001), ERVW1-IRF3 (r = 0.357; r² = 0.127; p = 0.004), ERV3-1-IRF7 (r = 0.314; r² = 0.098; p = 0.009), and ERV3-1-IRF3 (r = 0.324; r² = 0.104; p = 0.007). Using GEPIA Database in 30 cancer types, we detected a typical pattern of upregulation as here presented in MDS. We suggest TLR3 activation by ERVs is linked to MDS pathogenesis leading to bone marrow failure. Abnormal double-stranded RNA (dsRNA) expression of Endogenous Retroviruses (ERV) triggers TLR3 hyperactivation. This induces IRF3, IRF7, and NF-kB to translocate to the nucleus and activate transcription of IFNα/β which binds to the type I-IFN receptor promoting interferon response. Thus, just as TLR4 induces a crucial myeloid shift, the ERVs-TLR3 axis may play an important role in establishing one of the most striking characteristics in MDS, dyserythropoiesis.

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.

Suprabasin-A Review

Among the ~22,000 human genes, very few remain that have unknown functions. One such example is suprabasin (SBSN). Originally described as a component of the cornified envelope, the function of stratified epithelia-expressed SBSN is unknown. Both the lack of knowledge about the gene role under physiological conditions and the emerging link of SBSN to various human diseases, including cancer, attract research interest. The association of SBSN expression with poor prognosis of patients suffering from oesophageal carcinoma, glioblastoma multiforme, and myelodysplastic syndromes suggests that SBSN may play a role in human tumourigenesis. Three SBSN isoforms code for the secreted proteins with putative function as signalling molecules, yet with poorly described effects. In this first review about SBSN, we summarised the current knowledge accumulated since its original description, and we discuss the potential mechanisms and roles of SBSN in both physiology and pathology.

Modulation of IL-6/STAT3 signaling axis in CD4+FOXP3- T cells represents a potential antitumor mechanism of azacitidine

CD4+ T cells orchestrate immune responses and are actively engaged in shaping tumor immunity. Signal transducer and activator of transcription (STAT) signaling controls the epigenetic tuning of CD4+ T-cell differentiation and polarization, and perturbed STAT signaling networks in CD4+ T cells subvert antitumor immunity in malignancies. Azacitidine (AZA), the mainstay therapy for high-risk myelodysplastic syndromes (HR-MDS), affects CD4+ T-cell polarization and function, but whether this contributes to AZA efficacy is currently unknown. By using functional proteomic, transcriptomic, and mutational analyses in 73 HR-MDS patients undergoing AZA therapy, we demonstrate that responding patients exhibited a coordinated CD4+ T-cell immune response and downregulated the inflammatory cytokine signaling pathways in CD4+ T cells after AZA, in contrast to nonresponders who upregulated the same pathways. We further observed an AZA-mediated downregulation of intereukin-6 (IL-6)-induced STAT3 phosphorylation in CD4+FOXP3- conventional T cells (Tcons) that correlated independently with better response and survival, whereas it was also not associated with the mutation number and profile of the patients. The AZA-induced downregulation of IL-6/STAT3 axis in Tcons restored the STAT signaling architecture in CD4+ T-cell subsets, whereas STAT signaling networks remained disorganized in patients who upregulated IL-6/STAT3 activity in Tcons. Given the pivotal role of CD4+ T cells in adaptive immunity, our findings suggest that the downregulation of the IL-6/STAT3 pathway in Tcons potentially constitutes a previously unrecognized immune-mediated mechanism of action of AZA and sets the scene for developing rational strategies of AZA combinations with IL-6/STAT3 axis inhibitors.

Altered Spatial Composition of the Immune Cell Repertoire in Association to CD34+ Blasts in Myelodysplastic Syndromes and Secondary Acute Myeloid Leukemia

Simple Summary

Despite a relationship between immune dysregulation and the course of myelodysplastic syndromes (MDS) has been discussed, a detailed understanding of this phenomenon is still missing. Therefore, multiplex analyses of bone marrow biopsies (BMB) from patients with MDS and secondary acute myeloid leukemia (sAML) were performed in order to determine the repertoire of lymphocyte subpopulations and their distance to CD34⁺ blasts. In MDS and sAML samples, the composition, quantity, and spatial proximity of immune cell subsets to CD34⁺ blasts were heterogeneous and correlated to the blast counts, but not to the genetics of the diseases, while in non-neoplastic BMB no CD8⁺ and FOXP3⁺ T cells and only single MUM1p⁺ B/plasma cells were detected in a distance of ≤10 μm to CD34⁺ hematopoietic progenitor cells (HPSC). We conclude that CD8⁺ and FOXP3⁺ T cells are not part of the immediate surrounding of CD34⁺ HPSC.

Abstract

Background: Myelodysplastic syndromes (MDS) are caused by a stem cell failure and often include a dysfunction of the immune system. However, the relationship between spatial immune cell distribution within the bone marrow (BM), in relation to genetic features and the course of disease has not been analyzed in detail. Methods: Histotopography of immune cell subpopulations and their spatial distribution to CD34⁺ hematopoietic cells was determined by multispectral imaging (MSI) in 147 BM biopsies (BMB) from patients with MDS, secondary acute myeloid leukemia (sAML), and controls. Results: In MDS and sAML samples, a high inter-tumoral immune cell heterogeneity in spatial proximity to CD34⁺ blasts was found that was independent of genetic alterations, but correlated to blast counts. In controls, no CD8⁺ and FOXP3⁺ T cells and only single MUM1p⁺ B/plasma cells were detected in an area of ≤10 μm to CD34⁺ HSPC. Conclusions: CD8⁺ and FOXP3⁺ T cells are regularly seen in the 10 μm area around CD34⁺ blasts in MDS/sAML regardless of the course of the disease but lack in the surrounding of CD34⁺ HSPC in control samples. In addition, the frequencies of immune cell subsets in MDS and sAML BMB differ when compared to control BMB providing novel insights in immune deregulation.

Current and emerging strategies for management of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis with varying degrees of dysplasia and peripheral cytopenias. MDS are driven by structural chromosomal alterations and somatic mutations in neoplastic myeloid cells, which are supported by a tumorigenic and a proinflammatory marrow microenvironment. Current treatment strategies for lower-risk MDS focus on improving quality of life and cytopenias, while prolonging survival and delaying disease progression is the focus for higher-risk MDS. Several promising drugs are in the horizon, including the hypoxia-inducible factor stabilizer roxadustat, telomerase inhibitor imetelstat, oral hypomethylating agents (CC-486), TP53 modulators (APR-246 and ALRN-6924), and the anti-CD47 antibody magrolimab. Targeted therapies approved for acute myeloid leukemia treatment, such as isocitrate dehdyrogenase inhibitors and venetoclax, are also being studied for use in MDS. In this review, we provide a brief overview of pathogenesis and current treatment strategies in MDS followed by a discussion of newer agents that are under clinical investigation.