RESUMO
The dynamics of CD4+ T cell memory development remain to be examined at genome scale. In malaria-endemic regions, antimalarial chemoprevention protects long after its cessation and associates with effects on CD4+ T cells. We applied single-cell RNA sequencing and computational modelling to track memory development during Plasmodium infection and treatment. In the absence of central memory precursors, two trajectories developed as T helper 1 (TH1) and follicular helper T (TFH) transcriptomes contracted and partially coalesced over three weeks. Progeny of single clones populated TH1 and TFH trajectories, and fate-mapping suggested that there was minimal lineage plasticity. Relationships between TFH and central memory were revealed, with antimalarials modulating these responses and boosting TH1 recall. Finally, single-cell epigenomics confirmed that heterogeneity among effectors was partially reset in memory. Thus, the effector-to-memory transition in CD4+ T cells is gradual during malaria and is modulated by antiparasitic drugs. Graphical user interfaces are presented for examining gene-expression dynamics and gene-gene correlations ( http://haquelab.mdhs.unimelb.edu.au/cd4_memory/ ).
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Memória Imunológica , Malária/imunologia , Plasmodium/imunologia , Transcriptoma , Transferência Adotiva , Animais , Antimaláricos/farmacologia , Biomarcadores , Cromatina/genética , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Humanos , Malária/parasitologia , Malária/terapia , Camundongos , Plasmodium/efeitos dos fármacosRESUMO
The ultimate goal of bringing most new drugs to the clinic in hematological malignancy is to improve overall survival. However, the use of surrogate endpoints for overall survival is increasingly considered standard practice, since a well validated surrogate endpoint can accelerate the outcome assessment and facilitate better clinical trial design. Established examples include monitoring minimal residual disease in chronic myeloid leukemia and acute leukemia, and metabolic response assessment in lymphoma. However, what happens when a clinical trial endpoint that is not a good surrogate for disease-modifying potential becomes ingrained as an expected outcome, and new agents are expected or required to meet this endpoint to demonstrate "efficacy"? JAK inhibitors for myelofibrosis have a specific impact on reducing symptom burden and splenomegaly, but limited impact on the natural history of the disease. Since the introduction of ruxolitinib more than a decade ago there has been modest incremental success in clinical trials for myelofibrosis, but no major leap forward to alter the natural history of the disease. We argue that the clinical development of novel agents for myelofibrosis will be accelerated by moving away from using endpoints that are specifically tailored to measure the beneficial effects of JAK inhibitors. We propose that specific measures of relevant disease burden, such as reduction in mutation burden as determined by molecular endpoints, should replace established endpoints. Careful re-analysis of existing data and trials in progress is needed to identify the most useful surrogate endpoints for future MF trials and better serve patient interest.
RESUMO
Asciminib is a myristoyl site BCR::ABL1 inhibitor approved for chronic phase chronic myeloid leukaemia (CP-CML) patients failing ≥2 prior lines of therapy. The Australasian Leukaemia & Lymphoma Group (ALLG) conducted the ASCEND study to assess efficacy of asciminib for newly-diagnosed CP-CML. Patients commenced asciminib 40 mg twice daily (BID) and thereafter were managed according to molecular milestones. Patients with treatment failure, defined as BCR::ABL1 >10% (IS) at 3 or 6 months, or >1% at 12 or 18 months, received either imatinib, nilotinib or dasatinib in addition to asciminib. In patients with suboptimal response, defined as levels of 1-10% at 6 months, >0.1-1% at 12 months, or >0.01%-1% at 18 months, the asciminib dose was increased to 80 mg BID. With a median follow-up of 21 months (range 0-36), 82/101 patients continue asciminib. The most frequent reasons for treatment discontinuation were adverse events (6%), loss of response (4%) and withdrawn consent (5%). There were no deaths; one patient developed lymphoid blast crisis at 6 months. The co-primary endpoints were early molecular response (BCR::ABL1 ≤10% at 3 months), achieved in 93% (96% CI 86-97%), and major molecular response by 12 months achieved in 79%; (95% CI 69.7-86.8%), respectively. The cumulative incidence of MR4.5 was 53% by 24 months. One patient had 2 cerebrovascular events; no other arterial occlusive events were reported. Asciminib as frontline therapy in CP-CML produces high rates of molecular response with excellent tolerance and a low rate of discontinuation for toxicity. (ANZ Clinical Trials Registry ACTRN12620000851965).
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AKT activation is associated with many malignancies, where AKT acts, in part, by inhibiting FOXO tumor suppressors. We show a converse role for AKT/FOXOs in acute myeloid leukemia (AML). Rather than decreased FOXO activity, we observed that FOXOs are active in â¼40% of AML patient samples regardless of genetic subtype. We also observe this activity in human MLL-AF9 leukemia allele-induced AML in mice, where either activation of Akt or compound deletion of FoxO1/3/4 reduced leukemic cell growth, with the latter markedly diminishing leukemia-initiating cell (LIC) function in vivo and improving animal survival. FOXO inhibition resulted in myeloid maturation and subsequent AML cell death. FOXO activation inversely correlated with JNK/c-JUN signaling, and leukemic cells resistant to FOXO inhibition responded to JNK inhibition. These data reveal a molecular role for AKT/FOXO and JNK/c-JUN in maintaining a differentiation blockade that can be targeted to inhibit leukemias with a range of genetic lesions.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Animais , Antígenos CD34/metabolismo , Apoptose , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Células Cultivadas , Modelos Animais de Doenças , Proteína Forkhead Box O3 , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismoRESUMO
Janus kinases (JAKs) mediate responses to cytokines, hormones and growth factors in haematopoietic cells1,2. The JAK gene JAK2 is frequently mutated in the ageing haematopoietic system3,4 and in haematopoietic cancers5. JAK2 mutations constitutively activate downstream signalling and are drivers of myeloproliferative neoplasm (MPN). In clinical use, JAK inhibitors have mixed effects on the overall disease burden of JAK2-mutated clones6,7, prompting us to investigate the mechanism underlying disease persistence. Here, by in-depth phosphoproteome profiling, we identify proteins involved in mRNA processing as targets of mutant JAK2. We found that inactivation of YBX1, a post-translationally modified target of JAK2, sensitizes cells that persist despite treatment with JAK inhibitors to apoptosis and results in RNA mis-splicing, enrichment for retained introns and disruption of the transcriptional control of extracellular signal-regulated kinase (ERK) signalling. In combination with pharmacological JAK inhibition, YBX1 inactivation induces apoptosis in JAK2-dependent mouse and primary human cells, causing regression of the malignant clones in vivo, and inducing molecular remission. This identifies and validates a cell-intrinsic mechanism whereby differential protein phosphorylation causes splicing-dependent alterations of JAK2-ERK signalling and the maintenance of JAK2V617F malignant clones. Therapeutic targeting of YBX1-dependent ERK signalling in combination with JAK2 inhibition could thus eradicate cells harbouring mutations in JAK2.
Assuntos
Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Neoplasias/genética , Neoplasias/patologia , Proteína 1 de Ligação a Y-Box/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Células Clonais/metabolismo , Células Clonais/patologia , Feminino , Xenoenxertos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Íntrons/genética , Janus Quinase 2/antagonistas & inibidores , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Mutação , Transplante de Neoplasias , Neoplasias/tratamento farmacológico , Fosfoproteínas/análise , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteoma/análise , Proteômica , Splicing de RNA/genética , Indução de Remissão , Proteína 1 de Ligação a Y-Box/antagonistas & inibidores , Proteína 1 de Ligação a Y-Box/químicaRESUMO
Hematopoietic stem and progenitor cells (HSPCs) rely on a complex interplay among transcription factors (TFs) to regulate differentiation into mature blood cells. A heptad of TFs (FLI1, ERG, GATA2, RUNX1, TAL1, LYL1, LMO2) bind regulatory elements in bulk CD34+ HSPCs. However, whether specific heptad-TF combinations have distinct roles in regulating hematopoietic differentiation remains unknown. We mapped genome-wide chromatin contacts (HiC, H3K27ac, HiChIP), chromatin modifications (H3K4me3, H3K27ac, H3K27me3) and 10 TF binding profiles (heptad, PU.1, CTCF, STAG2) in HSPC subsets (stem/multipotent progenitors plus common myeloid, granulocyte macrophage, and megakaryocyte erythrocyte progenitors) and found TF occupancy and enhancer-promoter interactions varied significantly across cell types and were associated with cell-type-specific gene expression. Distinct regulatory elements were enriched with specific heptad-TF combinations, including stem-cell-specific elements with ERG, and myeloid- and erythroid-specific elements with combinations of FLI1, RUNX1, GATA2, TAL1, LYL1, and LMO2. Furthermore, heptad-occupied regions in HSPCs were subsequently bound by lineage-defining TFs, including PU.1 and GATA1, suggesting that heptad factors may prime regulatory elements for use in mature cell types. We also found that enhancers with cell-type-specific heptad occupancy shared a common grammar with respect to TF binding motifs, suggesting that combinatorial binding of TF complexes was at least partially regulated by features encoded in DNA sequence motifs. Taken together, this study comprehensively characterizes the gene regulatory landscape in rare subpopulations of human HSPCs. The accompanying data sets should serve as a valuable resource for understanding adult hematopoiesis and a framework for analyzing aberrant regulatory networks in leukemic cells.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core , Células-Tronco Hematopoéticas , Humanos , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Regulação da Expressão Gênica , Hematopoese/genética , Cromatina/metabolismoRESUMO
In an effort to identify novel drugs targeting fusion-oncogene-induced acute myeloid leukemia (AML), we performed high-resolution proteomic analysis. In AML1-ETO (AE)-driven AML, we uncovered a deregulation of phospholipase C (PLC) signaling. We identified PLCgamma 1 (PLCG1) as a specific target of the AE fusion protein that is induced after AE binding to intergenic regulatory DNA elements. Genetic inactivation of PLCG1 in murine and human AML inhibited AML1-ETO dependent self-renewal programs, leukemic proliferation, and leukemia maintenance in vivo. In contrast, PLCG1 was dispensable for normal hematopoietic stem and progenitor cell function. These findings are extended to and confirmed by pharmacologic perturbation of Ca++-signaling in AML1-ETO AML cells, indicating that the PLCG1 pathway poses an important therapeutic target for AML1-ETO+ leukemic stem cells.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Regulação Leucêmica da Expressão Gênica , Células-Tronco Hematopoéticas/patologia , Leucemia Mieloide Aguda/patologia , Células-Tronco Neoplásicas/patologia , Proteínas de Fusão Oncogênica/metabolismo , Fosfolipase C gama/metabolismo , Proteína 1 Parceira de Translocação de RUNX1/metabolismo , Animais , Autorrenovação Celular , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Camundongos , Células-Tronco Neoplásicas/metabolismo , Proteínas de Fusão Oncogênica/genética , Fosfolipase C gama/genética , Proteoma , Proteína 1 Parceira de Translocação de RUNX1/genética , Transcriptoma , Translocação GenéticaRESUMO
Pharmacologic targeting of chromatin-associated protein complexes has shown significant responses in KMT2A-rearranged (KMT2A-r) acute myeloid leukemia (AML) but resistance frequently develops to single agents. This points to a need for therapeutic combinations that target multiple mechanisms. To enhance our understanding of functional dependencies in KMT2A-r AML, we have used a proteomic approach to identify the catalytic immunoproteasome subunit PSMB8 as a specific vulnerability. Genetic and pharmacologic inactivation of PSMB8 results in impaired proliferation of murine and human leukemic cells while normal hematopoietic cells remain unaffected. Disruption of immunoproteasome function drives an increase in transcription factor BASP1 which in turn represses KMT2A-fusion protein target genes. Pharmacologic targeting of PSMB8 improves efficacy of Menin-inhibitors, synergistically reduces leukemia in human xenografts and shows preserved activity against Menin-inhibitor resistance mutations. This identifies and validates a cell-intrinsic mechanism whereby selective disruption of proteostasis results in altered transcription factor abundance and repression of oncogene-specific transcriptional networks. These data demonstrate that the immunoproteasome is a relevant therapeutic target in AML and that targeting the immunoproteasome in combination with Menin-inhibition could be a novel approach for treatment of KMT2A-r AML.
Assuntos
Leucemia Mieloide Aguda , Proteômica , Humanos , Camundongos , Animais , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Leucemia Mieloide Aguda/metabolismo , Fatores de Transcrição/genética , Mutação , Expressão GênicaRESUMO
Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment. Ifnlr1-/- mice displayed exaggerated GI GVHD and mortality independent of Paneth cells and alterations to the microbiome. Ifnlr1-/- intestinal organoid growth was significantly impaired, and targeted Ifnlr1 deficiency exhibited effects intrinsic to recipient Lgr5+ ISCs and natural killer cells. PEGylated recombinant IL-29 (PEG-rIL-29) treatment of naive mice enhanced Lgr5+ ISC numbers and organoid growth independent of both IL-22 and type I IFN and modulated proliferative and apoptosis gene sets in Lgr5+ ISCs. PEG-rIL-29 treatment improved survival, reduced GVHD severity, and enhanced epithelial proliferation and ISC-derived organoid growth after BMT. The preservation of ISC numbers in response to PEG-rIL-29 after BMT occurred both in the presence and absence of IFN-λ-signaling in recipient natural killer cells. IFN-λ is therefore an attractive and rapidly testable approach to prevent ISC loss and immunopathology during GVHD.
Assuntos
Transplante de Medula Óssea , Citocinas/farmacologia , Gastroenteropatias , Doença Enxerto-Hospedeiro , Interleucinas/farmacocinética , Transdução de Sinais , Animais , Citocinas/imunologia , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/genética , Gastroenteropatias/imunologia , Doença Enxerto-Hospedeiro/tratamento farmacológico , Doença Enxerto-Hospedeiro/genética , Doença Enxerto-Hospedeiro/imunologia , Interleucinas/imunologia , Camundongos , Camundongos Knockout , Receptores de Interferon/genética , Receptores de Interferon/imunologia , Índice de Gravidade de Doença , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Transplante HomólogoRESUMO
Selective targeting of BCL-2 with the BH3-mimetic venetoclax has been a transformative treatment for patients with various leukemias. TP-53 controls apoptosis upstream of where BCL-2 and its prosurvival relatives, such as MCL-1, act. Therefore, targeting these prosurvival proteins could trigger apoptosis across diverse blood cancers, irrespective of TP53 mutation status. Indeed, targeting BCL-2 has produced clinically relevant responses in blood cancers with aberrant TP-53. However, in our study, TP53-mutated or -deficient myeloid and lymphoid leukemias outcompeted isogenic controls with intact TP-53, unless sufficient concentrations of BH3-mimetics targeting BCL-2 or MCL-1 were applied. Strikingly, tumor cells with TP-53 dysfunction escaped and thrived over time if inhibition of BCL-2 or MCL-1 was sublethal, in part because of an increased threshold for BAX/BAK activation in these cells. Our study revealed the key role of TP-53 in shaping long-term responses to BH3-mimetic drugs and reconciled the disparate pattern of initial clinical response to venetoclax, followed by subsequent treatment failure among patients with TP53-mutant chronic lymphocytic leukemia or acute myeloid leukemia. In contrast to BH3-mimetics targeting just BCL-2 or MCL-1 at doses that are individually sublethal, a combined BH3-mimetic approach targeting both prosurvival proteins enhanced lethality and durably suppressed the leukemia burden, regardless of TP53 mutation status. Our findings highlight the importance of using sufficiently lethal treatment strategies to maximize outcomes of patients with TP53-mutant disease. In addition, our findings caution against use of sublethal BH3-mimetic drug regimens that may enhance the risk of disease progression driven by emergent TP53-mutant clones.
Assuntos
Antineoplásicos/farmacologia , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Indolizinas/farmacologia , Isoquinolinas/farmacologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Mieloide Aguda/tratamento farmacológico , Morfolinas/farmacologia , Proteínas de Neoplasias/fisiologia , Fragmentos de Peptídeos/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Sulfonamidas/farmacologia , Proteína Supressora de Tumor p53/fisiologia , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose/fisiologia , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Dano ao DNA , Genes p53 , Humanos , Indolizinas/uso terapêutico , Subunidade alfa de Receptor de Interleucina-2/deficiência , Isoquinolinas/uso terapêutico , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/terapia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Morfolinas/uso terapêutico , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Proteínas de Neoplasias/antagonistas & inibidores , Fosforilação Oxidativa/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sulfonamidas/administração & dosagem , Sulfonamidas/uso terapêutico , Proteína Supressora de Tumor p53/deficiência , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The DNA hypomethylating agents (HMA) azacitidine (AZA) and decitabine (DAC) improve survival and transfusion independence in myelodysplastic syndrome (MDS) and enable a low intensity cytotoxic treatment for aged AML patients unsuitable for intensive chemotherapy, particularly in combination with novel agents. The proposed mechanism of AZA and DAC relies on active DNA replication and therefore patient responses are only observed after multiple cycles of treatment. Although extended dosing may provide the optimal scheduling, the reliance of injectable formulation of the drug limits it to intermittent treatment. Recently, an oral formulation of AZA demonstrated significantly improved patient relapse free survival (RFS) and overall survival (OS) when used as maintenance after chemotherapy for AML. In addition, both DAC and AZA were found to be highly effective to improve survival in elderly patients with AML through combination with other drugs. These recent exciting results have changed the therapeutic paradigm for elderly patients with AML. In light of this, we review current knowledge on HMA mechanism of action, clinical trials exploring dosing and scheduling, and recent HMA combination therapies to enhance efficacy.
Assuntos
Leucemia Mieloide Aguda , Síndromes Mielodisplásicas , Idoso , Azacitidina/uso terapêutico , Decitabina/uso terapêutico , Terapia Genética , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/genética , Resultado do TratamentoRESUMO
Haematopoietic stem cells (HSCs) are responsible for the lifelong production of blood cells. The accumulation of DNA damage in HSCs is a hallmark of ageing and is probably a major contributing factor in age-related tissue degeneration and malignant transformation. A number of accelerated ageing syndromes are associated with defective DNA repair and genomic instability, including the most common inherited bone marrow failure syndrome, Fanconi anaemia. However, the physiological source of DNA damage in HSCs from both normal and diseased individuals remains unclear. Here we show in mice that DNA damage is a direct consequence of inducing HSCs to exit their homeostatic quiescent state in response to conditions that model physiological stress, such as infection or chronic blood loss. Repeated activation of HSCs out of their dormant state provoked the attrition of normal HSCs and, in the case of mice with a non-functional Fanconi anaemia DNA repair pathway, led to a complete collapse of the haematopoietic system, which phenocopied the highly penetrant bone marrow failure seen in Fanconi anaemia patients. Our findings establish a novel link between physiological stress and DNA damage in normal HSCs and provide a mechanistic explanation for the universal accumulation of DNA damage in HSCs during ageing and the accelerated failure of the haematopoietic system in Fanconi anaemia patients.
Assuntos
Ciclo Celular , Dano ao DNA , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Animais , Medula Óssea/patologia , Morte Celular , Proliferação de Células , Anemia de Fanconi/metabolismo , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Estresse FisiológicoRESUMO
Bromodomain and extra terminal protein (BET) inhibitors are first-in-class targeted therapies that deliver a new therapeutic opportunity by directly targeting bromodomain proteins that bind acetylated chromatin marks. Early clinical trials have shown promise, especially in acute myeloid leukaemia, and therefore the evaluation of resistance mechanisms is crucial to optimize the clinical efficacy of these drugs. Here we use primary mouse haematopoietic stem and progenitor cells immortalized with the fusion protein MLL-AF9 to generate several single-cell clones that demonstrate resistance, in vitro and in vivo, to the prototypical BET inhibitor, I-BET. Resistance to I-BET confers cross-resistance to chemically distinct BET inhibitors such as JQ1, as well as resistance to genetic knockdown of BET proteins. Resistance is not mediated through increased drug efflux or metabolism, but is shown to emerge from leukaemia stem cells both ex vivo and in vivo. Chromatin-bound BRD4 is globally reduced in resistant cells, whereas the expression of key target genes such as Myc remains unaltered, highlighting the existence of alternative mechanisms to regulate transcription. We demonstrate that resistance to BET inhibitors, in human and mouse leukaemia cells, is in part a consequence of increased Wnt/ß-catenin signalling, and negative regulation of this pathway results in restoration of sensitivity to I-BET in vitro and in vivo. Together, these findings provide new insights into the biology of acute myeloid leukaemia, highlight potential therapeutic limitations of BET inhibitors, and identify strategies that may enhance the clinical utility of these unique targeted therapies.
Assuntos
Benzodiazepinas/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Proteínas Nucleares/antagonistas & inibidores , Fatores de Transcrição/antagonistas & inibidores , Animais , Azepinas/farmacologia , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Células Cultivadas , Cromatina/metabolismo , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Células Clonais/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Epigênese Genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genes myc/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Terapia de Alvo Molecular , Células-Tronco Neoplásicas/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica/efeitos dos fármacos , Triazóis/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos , beta Catenina/metabolismoRESUMO
Myeloproliferative neoplasms (MPNs) are a group of blood cancers that arise following the sequential acquisition of genetic lesions in hematopoietic stem and progenitor cells (HSPCs). We identify mutational cooperation between Jak2V617F expression and Dnmt3a loss that drives progression from early-stage polycythemia vera to advanced myelofibrosis. Using in vivo, clustered regularly interspaced short palindromic repeats (CRISPR) with CRISPR-associated protein 9 (Cas9) disruption of Dnmt3a in Jak2V617F knockin HSPC, we show that Dnmt3a loss blocks the accumulation of erythroid elements and causes fibrotic infiltration within the bone marrow and spleen. Transcriptional analysis and integration with human data sets identified a core DNMT3A-driven gene-expression program shared across multiple models and contexts of Dnmt3a loss. Aberrant self-renewal and inflammatory signaling were seen in Dnmt3a-/- Jak2V617F HSPC, driven by increased chromatin accessibility at enhancer elements. These findings identify oncogenic cooperativity between Jak2V617F-driven MPN and Dnmt3a loss, leading to activation of HSPC enhancer-driven inflammatory signaling.
Assuntos
Substituição de Aminoácidos , DNA (Citosina-5-)-Metiltransferases , Neoplasias Hematológicas , Células-Tronco Hematopoéticas , Mutação de Sentido Incorreto , Mielofibrose Primária , Transdução de Sinais/genética , Animais , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA Metiltransferase 3A , Neoplasias Hematológicas/enzimologia , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , Células-Tronco Hematopoéticas/enzimologia , Células-Tronco Hematopoéticas/patologia , Humanos , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Camundongos , Camundongos Mutantes , Mielofibrose Primária/enzimologia , Mielofibrose Primária/genética , Mielofibrose Primária/patologiaRESUMO
Differentiation of CD4+ Th cells is critical for immunity to malaria. Several innate immune signaling pathways have been implicated in the detection of blood-stage Plasmodium parasites, yet their influence over Th cell immunity remains unclear. In this study, we used Plasmodium-reactive TCR transgenic CD4+ T cells, termed PbTII cells, during nonlethal P. chabaudi chabaudi AS and P. yoelii 17XNL infection in mice, to examine Th cell development in vivo. We found no role for caspase1/11, stimulator of IFN genes, or mitochondrial antiviral-signaling protein, and only modest roles for MyD88 and TRIF-dependent signaling in controlling PbTII cell expansion. In contrast, IFN regulatory factor 3 (IRF3) was important for supporting PbTII expansion, promoting Th1 over T follicular helper (Tfh) differentiation, and controlling parasites during the first week of infection. IRF3 was not required for early priming by conventional dendritic cells, but was essential for promoting CXCL9 and MHC class II expression by inflammatory monocytes that supported PbTII responses in the spleen. Thereafter, IRF3-deficiency boosted Tfh responses, germinal center B cell and memory B cell development, parasite-specific Ab production, and resolution of infection. We also noted a B cell-intrinsic role for IRF3 in regulating humoral immune responses. Thus, we revealed roles for IRF3 in balancing Th1- and Tfh-dependent immunity during nonlethal infection with blood-stage Plasmodium parasites.
Assuntos
Diferenciação Celular/imunologia , Fator Regulador 3 de Interferon/imunologia , Malária/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Células Th1/imunologia , Animais , Feminino , Centro Germinativo/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Baço/imunologiaRESUMO
INTRODUCTION: A pandemic coronavirus, SARS-CoV-2, causes COVID-19, a potentially life-threatening respiratory disease. Patients with cancer may have compromised immunity due to their malignancy and/or treatment, and may be at elevated risk of severe COVID-19. Community transmission of COVID-19 could overwhelm health care services, compromising delivery of cancer care. This interim consensus guidance provides advice for clinicians managing patients with cancer during the pandemic. MAIN RECOMMENDATIONS: During the COVID-19 pandemic: In patients with cancer with fever and/or respiratory symptoms, consider causes in addition to COVID-19, including other infections and therapy-related pneumonitis. For suspected or confirmed COVID-19, discuss temporary cessation of cancer therapy with a relevant specialist. Provide information on COVID-19 for patients and carers. Adopt measures within cancer centres to reduce risk of nosocomial SARS-CoV-2 acquisition; support population-wide social distancing; reduce demand on acute services; ensure adequate staffing; and provide culturally safe care. Measures should be equitable, transparent and proportionate to the COVID-19 threat. Consider the risks and benefits of modifying cancer therapies due to COVID-19. Communicate treatment modifications, and review once health service capacity allows. Consider potential impacts of COVID-19 on the blood supply and availability of stem cell donors. Discuss and document goals of care, and involve palliative care services in contingency planning. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This interim consensus guidance provides a framework for clinicians managing patients with cancer during the COVID-19 pandemic. In view of the rapidly changing situation, clinicians must also monitor national, state, local and institutional policies, which will take precedence. ENDORSED BY: Australasian Leukaemia and Lymphoma Group; Australasian Lung Cancer Trials Group; Australian and New Zealand Children's Haematology/Oncology Group; Australia and New Zealand Society of Palliative Medicine; Australasian Society for Infectious Diseases; Bone Marrow Transplantation Society of Australia and New Zealand; Cancer Council Australia; Cancer Nurses Society of Australia; Cancer Society of New Zealand; Clinical Oncology Society of Australia; Haematology Society of Australia and New Zealand; National Centre for Infections in Cancer; New Zealand Cancer Control Agency; New Zealand Society for Oncology; and Palliative Care Australia.
Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Hematologia/normas , Oncologia/normas , Pneumonia Viral/complicações , Guias de Prática Clínica como Assunto , Austrália , COVID-19 , Consenso , Infecções por Coronavirus/virologia , Doenças Hematológicas/virologia , Humanos , Neoplasias/virologia , Nova Zelândia , Pandemias , Pneumonia Viral/virologia , SARS-CoV-2RESUMO
Allogeneic bone marrow transplantation (allo-BMT) is a curative therapy for hematological malignancies, but is associated with significant complications, principally graft-versus-host disease (GVHD) and opportunistic infections. Natural killer (NK) cells mediate important innate immunity that provides a temporal bridge until the reconstruction of adaptive immunity. Here, we show that the development of GVHD after allo-BMT prevented NK-cell reconstitution, particularly within the maturing M1 and M2 NK-cell subsets in association with exaggerated activation, apoptosis, and autophagy. Donor T cells were critical in this process by limiting the availability of interleukin 15 (IL-15), and administration of IL-15/IL-15Rα or immune suppression with rapamycin could restore NK-cell reconstitution. Importantly, the NK-cell defect induced by GVHD resulted in the failure of NK-cell-dependent in vivo cytotoxicity and graft-versus-leukemia effects. Control of cytomegalovirus infection after allo-BMT was also impaired during GVHD. Thus, during GVHD, donor T cells compete with NK cells for IL-15 thereby inducing profound defects in NK-cell reconstitution that compromise both leukemia and pathogen-specific immunity.
Assuntos
Transplante de Medula Óssea/efeitos adversos , Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Doença Enxerto-Hospedeiro/imunologia , Imunidade Inata , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/patologia , Leucemia/imunologia , Animais , Autofagia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Linhagem Celular Tumoral , Citomegalovirus/isolamento & purificação , Infecções por Citomegalovirus/complicações , Infecções por Citomegalovirus/patologia , Feminino , Doença Enxerto-Hospedeiro/complicações , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/patologia , Humanos , Interleucina-15/imunologia , Leucemia/complicações , Leucemia/patologia , Leucemia/terapia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Transplante Homólogo/efeitos adversosRESUMO
Hematopoietic stem and progenitor cells (HSPCs) are vulnerable to endogenous damage and defects in DNA repair can limit their function. The 2 single-stranded DNA (ssDNA) binding proteins SSB1 and SSB2 are crucial regulators of the DNA damage response; however, their overlapping roles during normal physiology are incompletely understood. We generated mice in which both Ssb1 and Ssb2 were constitutively or conditionally deleted. Constitutive Ssb1/Ssb2 double knockout (DKO) caused early embryonic lethality, whereas conditional Ssb1/Ssb2 double knockout (cDKO) in adult mice resulted in acute lethality due to bone marrow failure and intestinal atrophy featuring stem and progenitor cell depletion, a phenotype unexpected from the previously reported single knockout models of Ssb1 or Ssb2 Mechanistically, cDKO HSPCs showed altered replication fork dynamics, massive accumulation of DNA damage, genome-wide double-strand breaks enriched at Ssb-binding regions and CpG islands, together with the accumulation of R-loops and cytosolic ssDNA. Transcriptional profiling of cDKO HSPCs revealed the activation of p53 and interferon (IFN) pathways, which enforced cell cycling in quiescent HSPCs, resulting in their apoptotic death. The rapid cell death phenotype was reproducible in in vitro cultured cDKO-hematopoietic stem cells, which were significantly rescued by nucleotide supplementation or after depletion of p53. Collectively, Ssb1 and Ssb2 control crucial aspects of HSPC function, including proliferation and survival in vivo by resolving replicative stress to maintain genomic stability.
Assuntos
Proliferação de Células/fisiologia , Quebras de DNA de Cadeia Dupla , Instabilidade Genômica/fisiologia , Células-Tronco Hematopoéticas/metabolismo , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Animais , Sobrevivência Celular/fisiologia , Ilhas de CpG/fisiologia , Células-Tronco Hematopoéticas/citologia , Camundongos , Camundongos Knockout , Proteínas Supressoras da Sinalização de Citocina/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
The classical myeloproliferative neoplasms (MPN) are uncommon clonal haemopoietic malignancies characterised by excessive production of mature blood cells. Clinically, they are associated with thrombosis, haemorrhage, varying degrees of constitutional disturbance and a risk of progression to myelofibrosis or acute myeloid leukaemia. Many of the disease manifestations may be ameliorated by treatment with interferon-α (IFN), but its use in Australian MPN patients has been limited due to the inconvenience of frequent injections and side-effects. The pegylated form of IFN is a long-acting preparation, which is better tolerated, and its Pharmaceutical Benefits Scheme listing is likely to lead to increased usage. We review the literature on risks and benefits of IFN treatment for MPN, suggest criteria for patient selection in each of these diseases and discuss strategies to manage the side-effects of pegylated IFN.