Browse Articles
Discover research articles across all indexed journals
Duployez N, Largeaud L, Duchmann M, et al. Prognostic impact of <i>DDX41</i> germline mutations in intensively treated acute myeloid leukemia patients: an ALFA-FILO study. <i>Blood</i>. 2022;140(7):756-768.
m6A meets T-ALL: HNRNPC and FTO as new therapeutic targets
Type 1 von Willebrand disease: does it need a sibling?
Epigenetic drug remedies for SCD root cause pathophysiology
Weathering the HLH storm and redesigning clinical trials
Efficacy of a novel BCL-xL degrader, DT2216, in preclinical models of <i>JAK2</i>-mutated post-MPN AML
Abstract Acute myeloid leukemia (AML) that evolves from myeloproliferative neoplasm (MPN) is known as post-MPN AML. Current treatments do not significantly extend survival beyond 12 months. B-cell lymphoma-extra large (BCL-xL) has been found to be overexpressed in leucocytes from patients with MPN, making it a potential therapeutic target. We investigated the role of BCL-xL in post-MPN AML and tested the efficacy of DT2216, a platelet-sparing BCL-xL proteolysis-targeting chimera, in preclinical models of post-MPN AML. We found that BCL2L1, the gene encoding BCL-xL, is expressed at higher levels in patients with post-MPN AML than in those with de novo AML. Single-cell multiomics analysis revealed that leukemia cells harboring both MPN-driver and TP53 mutations exhibited higher BCL2L1 expression and elevated scores for leukemia stem cell, megakaryocyte development, and erythroid progenitor than wild-type cells. BH3 profiling confirmed a strong dependence on BCL-xL in post-MPN AML cells. DT2216 alone, or in combination with standard AML/MPN therapies, effectively degraded BCL-xL, reduced the apoptotic threshold, and induced apoptosis in post-MPN AML cells. DT2216 effectively eliminated viable cells in JAK2-mutant AML cell lines, induced pluripotent stem cell–derived hematopoietic progenitor cells, primary samples, and reduced tumor burden in cell line–derived xenograft model in vivo by degrading BCL-xL. DT2216, either as a single agent or in combination with azacytidine, effectively inhibited the clonogenic potential of CD34+ leukemia cells from patients with post-MPN AML. In summary, our data indicate that the survival of post-MPN AML is BCL-xL dependent, and DT2216 may offer therapeutic advantage in this high-risk leukemia subset with limited treatment options.
Richter transformation recommendations
Qualitative low VWF
Novel, potent, and orally bioavailable LSD1 inhibitors induce fetal hemoglobin synthesis in a sickle cell disease mouse model
Abstract Small molecules that inhibit LSD1 (lysine-specific demethylase 1, KDM1A) have been shown to induce abundant fetal hemoglobin (HbF) levels in red blood cells both in vitro and in vivo, therefore potentially serving as potent and cost-effective therapeutics to treat the β-globinopathies, sickle cell disease (SCD), and β-thalassemia major (TM). However, most LSD1 inhibitors (LSD1is) that induce HbF in vivo are covalent and irreversible, which leads to adverse effects. In this study, we utilized structure-aided drug design to develop potent new reversible LSD1is, leading to robust γ-globin expression in vitro. Moreover, in a mouse model of SCD, oral administration of these novel inhibitors leads to significant HbF elevation and alleviation of multiple features of disease pathology that are the usual consequences of SCD. In addition, we discovered that combined treatment of an LSD1i with a BRD4 degrader (BD-9136) represses the induction of RUNX1 and PU.1, thereby rescuing the erythroid to myeloid lineage conversion that accompanies LSD1is in hematopoiesis. The data indicate that this new generation of LSD1is can effectively induce HbF levels, reduce SCD pathologies, and are well tolerated by oral administration in SCD mice. We anticipate that the combination of these or related binary compounds offer exciting new therapeutic possibilities for treating SCD and TM.
Ruxolitinib combined with dexamethasone for adult patients with newly diagnosed hemophagocytic lymphohistiocytosis in China
Abstract Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome, and the overall survival (OS) of adult patients is poor. Ruxolitinib, a Janus kinase 1/2 (JAK1/2) inhibitor, has shown promise in treating HLH and exerts synergistic effects when combined with dexamethasone. Our pilot study preliminarily demonstrated that the combination of ruxolitinib and dexamethasone (Ru-D regimen) had a high response rate and led to favorable short-term survival outcomes in adult patients with HLH. In this prospective phase 2 clinical trial, we propose the Ru-D regimen as a first-line treatment for adults newly diagnosed as having HLH with unknown triggers. A total of 28 Chinese patients were enrolled, and the median follow-up time was 25.1 months (range, 0.87-34.0). The 2-month OS rate (the primary end point) was 85.7%, which exceeded our expected 2-month OS rate of 75%. The 6-month and 2-year OS rates were 67.9% (19/28) and 53.6% (15/28), respectively. The median OS of patients with lymphoma-associated HLH (LAHS) was 5.8 months, and most of these patients had natural killer/T-cell lymphoma. In contrast, the 2-year OS rate of patients without LAHS was 75%. The overall response rate was 85.7% (24/28); of 28 patients, 5 (17.9%) achieved a complete response during the Ru-D regimen. Overall, the Ru-D regimen was well tolerated in patients with HLH. This study demonstrates the efficacy and safety of the Ru-D regimen in adults newly diagnosed as having HLH with unknown triggers and warrants a phase 3 randomized controlled study. This trial was registered at www.chictr.org.cn as #ChiCTR2100049996).
Unusual suspects: a surprise cast in making blood stem cells
HNRNPC and m6A RNA methylation control oncogenic transcription and metabolism in T-cell leukemia
Abstract RNA homeostasis is dysregulated in cancer and affects disease progression and therapy resistance. N6-methyladenosine (m6A), the most abundant epitranscriptomic modification in eukaryotic messenger RNA, plays a pivotal role in RNA biology, affecting transcript stability, translation, and splicing. Our study uncovers the extensive m6A changes in patients with T-cell acute lymphoblastic leukemia (T-ALL), to our knowledge, for the first time. It reveals m6A’s regulatory role in the oncogenic MYC and cholesterol biosynthesis pathways. In addition, we discovered that T-ALL is highly dependent on the m6A reader heterogeneous nuclear ribonucleoprotein C (HNRNPC). HNRNPC is transcriptionally controlled by MYC and is an essential regulator of m6A-modified transcripts. Consequently, transcriptional silencing of HNRNPC profoundly impairs oncogenic pathways and critically diminishes leukemia cell growth. In addition, the levels of the m6A demethylase fat mass and obesity-associated protein (FTO) are significantly elevated in T-ALL cells compared with normal cells, and to other types of leukemia. Targeting FTO shows therapeutic potential in preclinical disease models and synergizes with clinically relevant therapeutics. Our findings underscore the integral role of RNA methylation in orchestrating cancer cell oncogene expression and metabolism and highlight promising novel therapeutic avenues for the treatment of T-cell leukemia.
Proteostasis disruption in inherited bone marrow failure syndromes
Abstract Inherited bone marrow failure syndromes (IBMFS) are genetic disorders of impaired hematopoiesis that manifest in childhood with both cytopenias and extrahematologic findings. Although several IBMFS are categorized as ribosomopathies owing to shared underlying ribosomal dysfunction, there is a broader disruption of the protein homeostasis (proteostasis) network across both classic and emerging IBMFS. Precise regulation of the proteostasis network, including mechanisms of protein synthesis, folding, trafficking, and degradation and associated stress response pathways, has emerged as essential for maintaining hematopoietic stem cell function, providing new potential mechanistic insights into IBMFS pathogenesis. Furthermore, the varied clinical trajectories of patients with IBMFS with possible divergent outcomes of malignancy and spontaneous remission may reflect developmental and temporal changes in proteostasis activity and be driven by strong selective pressures to restore proteostasis. These new insights are spurring fresh therapeutic approaches to target proteostasis. Thus, further evaluation of proteostasis regulation and the consequences of proteostasis disruption in IBMFS could aid in developing new biomarkers, therapeutic agents, and preventive approaches for patients.
Platelet NLRP6 protects against microvascular thrombosis in sepsis
Abstract Sepsis is characterized by a systemic inflammation and microvascular thrombosis induced by infection. The nucleotide-oligomerization domain–like receptor family pyrin domain containing 6 protein (NLRP6) possesses both proinflammatory and anti-inflammatory abilities with cell type–specific or tissue-specific functions. However, the role of cell type–specific NLRP6 in sepsis remains poorly understood. In this study, we detected NLRP6 expression in platelets. By using platelet-specific NLRP6 knockout mice and the cecal ligation and puncture model of sepsis, we demonstrated that deletion of platelet NLRP6 increased the mortality; enhanced microvascular thrombosis in the lung and liver; and promoted platelet activation, platelet-neutrophil interactions, as well as the neutrophil extracellular trap (NET) formation after sepsis. Platelet function analysis in vitro showed that deletion of NLRP6 enhanced platelet aggregation, activation, and granules release. In addition, NLRP6 deletion promoted platelet NF-κB signaling via sustaining transforming growth factor-β activated kinase 1–binding protein 1 (TAB1) expression independent of the inflammasome. Moreover, inhibition of NF-κB signaling abolished the aggravated effects of the absence of platelet NLRP6 on the intravascular microthrombosis and NET formation in sepsis and increased the overall survival. Mechanistically, NLRP6 facilitated the interaction between tripartite motif–containing protein 21 (TRIM21) and TAB1 in activated platelets, resulting in K48-linked polyubiquitination of TAB1 and subsequent degradation. Finally, sepsis plasma triggered TAB1 degradation mediated by NLRP6/TRIM21 in normal healthy platelets through toll-like receptor 4/myeloid differentiation primary response 88. Our study identifies a novel protective role of platelet NLRP6 in microvascular thrombosis during sepsis, implying it as a novel target for the treatment of sepsis.