| 1. |
- Baliakas, Panagiotis, 1977-, et al.
(författare)
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Nordic Guidelines for Germline Predisposition to Myeloid Neoplasms in Adults: Recommendations for Genetic Diagnosis, Clinical Management and Follow-up
- 2019
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Ingår i: HemaSphere. - : LIPPINCOTT WILLIAMS & WILKINS. - 2572-9241. ; 3:6
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Tidskriftsartikel (refereegranskat)abstract
- Myeloid neoplasms (MNs) with germline predisposition have recently been recognized as novel entities in the latest World Health Organization (WHO) classification for MNs. Individuals with MNs due to germline predisposition exhibit increased risk for the development of MNs, mainly acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Setting the diagnosis of MN with germline predisposition is of crucial clinical significance since it may tailor therapy, dictate the selection of donor for allogeneic hematopoietic stem cell transplantation (allo-HSCT), determine the conditioning regimen, enable relevant prophylactic measures and early intervention or contribute to avoid unnecessary or even harmful medication. Finally, it allows for genetic counseling and follow-up of at-risk family members. Identification of these patients in the clinical setting is challenging, as there is no consensus due to lack of evidence regarding the criteria defining the patients who should be tested for these conditions. In addition, even in cases with a strong suspicion of a MN with germline predisposition, no standard diagnostic algorithm is available. We present the first version of the Nordic recommendations for diagnostics, surveillance and management including considerations for allo-HSCT for patients and carriers of a germline mutation predisposing to the development of MNs.
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| 2. |
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| 3. |
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| 4. |
- Behrens, Kira, et al.
(författare)
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RUNX1 cooperates with FLT3-ITD to induce leukemia
- 2017
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Ingår i: Journal of Experimental Medicine. - : ROCKEFELLER UNIV PRESS. - 0022-1007 .- 1540-9538. ; 214:3, s. 737-752
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Tidskriftsartikel (refereegranskat)abstract
- Acute myeloid leukemia (AML) is induced by the cooperative action of deregulated genes that perturb self-renewal, proliferation, and differentiation. Internal tandem duplications (ITDs) in the FLT3 receptor tyrosine kinase are common mutations in AML, confer poor prognosis, and stimulate myeloproliferation. AML patient samples with FLT3-ITD express high levels of RUNX1, a transcription factor with known tumor-suppressor function. In this study, to understand this paradox, we investigated the impact of RUNX1 and FLT3-ITD coexpression. FLT3-ITD directly impacts on RUNX1 activity, whereby up-regulated and phosphorylated RUNX1 cooperates with FLT3-ITD to induce AML. Inactivating RUNX1 in tumors releases the differentiation block and down-regulates genes controlling ribosome biogenesis. We identified Hhex as a direct target of RUNX1 and FLT3-ITD stimulation and confirmed high HHEX expression in FLT3-ITD AMLs. HHEX could replace RUNX1 in cooperating with FLT3-ITD to induce AML. These results establish and elucidate the unanticipated oncogenic function of RUNX1 in AML. We predict that blocking RUNX1 activity will greatly enhance current therapeutic approaches using FLT3 inhibitors.
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| 5. |
- Cammenga, Jörg
(författare)
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Gatekeeper pathways and cellular background in the pathogenesis and therapy of AML
- 2005
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 19:10, s. 1719-1728
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Forskningsöversikt (refereegranskat)abstract
- Acute myelogenous leukemia (AML) is characterized by the accumulation of immature cells due to disturbed differentiation and proliferation of the myeloid lineage. Genetic alterations affecting transcription factors and receptor tyrosine kinases have been identified in AML and causally linked to the disease. The goal of this review is to address the role of the different genetic alterations in self-renewal and proliferation and to discuss the cellular background in which these events occur during the pathogenesis of AML. Data from AML samples, clinical studies and mouse models for AML will be used to support the different theories regarding the leukemogenesis of AML. Finally, this review wants to highlight the implication of these findings for the therapy of AML.
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| 6. |
- Cammenga, Jörg
(författare)
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Of gains and losses : SAMD9/SAMD9L and monosomy 7 in myelodysplastic syndrome
- 2024
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Ingår i: Experimental Hematology. - 0301-472X. ; 134
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Forskningsöversikt (refereegranskat)abstract
- SAMD9 and SAMD9L are two interferon-regulated genes located adjacent to each other on chromosome 7q21.2. Germline gain-of-function (GL GOF) mutations in SAMD9/SAMD9L are the genetic cause of MIRAGE syndrome, ataxia-pancytopenia (ATXPC) syndrome, myeloid leukemia syndrome with monosomy 7 (MLSM7), refractory cytopenia of childhood (RCC), transient monosomy 7 in children, SAMD9L-associated autoinflammatory disease (SAAD), and a proportion of inherited aplastic anemia and bone marrow failure syndromes. The myeloid neoplasms associated with GL GOF SAMD9/SAMD9L mutations have been included in the World Health Organization (WHO) 2022 classification. The discovery of SAMD9/SAMD9L-related diseases has revealed some interesting pathobiological mechanisms, such as a high rate of primary somatic compensation, with one of the mechanisms being (transient) monosomy 7 a mechanism also described as “adaption by aneuploidy.” The somatic compensation in the blood can complicate the diagnosis of SAMD9/SAMD9L-related disease when relying on hematopoietic tissues for diagnosis. Recently, GL loss-of function (LOF) mutations have been identified in older individuals with myeloid malignancies in accordance with a mouse model of SAMD9L loss that develops a myelodysplastic syndrome (MDS)-like disease late in life. The discovery of SAMD9/SAMD9L-associated syndromes has resulted in a deeper understanding of the genetics and biology of diseases/syndromes that were previously oblivious and thought to be unrelated to each other. Besides giving an overview of the literature, this review wants to also provide some practical guidance for the classification of SAMD9/SAMD9L variants that is complicated by the nonrecurrent nature of these mutations but also by the fact that both GL GOF, as well as loss-of-function mutations, have been identified.
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| 7. |
- Czerw, Tomasz, et al.
(författare)
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Impact of donor-derived CD34+infused cell dose on outcomes of patients undergoing allo-HCT following reduced intensity regimen for myelofibrosis: a study from the Chronic Malignancies Working Party of the EBMT
- 2022
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Ingår i: Bone Marrow Transplantation. - : SPRINGER NATURE. - 0268-3369 .- 1476-5365. ; 57, s. 261-270
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Tidskriftsartikel (refereegranskat)abstract
- The optimal CD34 + cell dose in the setting of RIC allo-HCT for myelofibrosis (MF) remains unknown. We retrospectively analyzed 657 patients with primary or secondary MF transplanted with use of peripheral blood (PB) stem cells after fludarabine/melphalan or fludarabine/busulfan RIC regimen. Median patient age was 58 (range, 22-76) years. Donors were HLA-identical sibling (MSD) or unrelated (UD). Median follow-up was 46 (2-194) months. Patients transplanted with higher doses of CD34 + cells (>7.0 x 10(6)/kg), had an increased chance of achievement of both neutrophil (hazard ratio (HR), 1.46; P < 0.001) and platelet engraftment (HR, 1.43; P < 0.001). In a model with interaction, for patients transplanted from a MSD, higher CD34 + dose was associated with improved overall survival (HR, 0.63; P = 0.04) and relapse-free survival (HR, 0.61; P = 0.02), lower risk of non-relapse mortality (HR, 0.57; P = 0.04) and higher rate of platelet engraftment. The combined effect of higher cell dose and UD was apparent only for higher neutrophil and platelet recovery rate. We did not document any detrimental effect of high CD34 + dose on transplant outcomes. More bulky splenomegaly was an adverse factor for survival, engraftment and NRM. Our analysis suggests a potential benefit for MF patients undergoing RIC PB-allo-HCT receiving more than 7.0 x 10(6)/kg CD34 + cells.
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| 8. |
- Davidsson, Josef, et al.
(författare)
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SAMD9 and SAMD9L in inherited predisposition to ataxia, pancytopenia, and myeloid malignancies
- 2018
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 32:5, s. 1106-1115
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Tidskriftsartikel (refereegranskat)abstract
- Germline mutations in the SAMD9 and SAMD9L genes, located in tandem on chromosome 7, are associated with a clinical spectrum of disorders including the MIRAGE syndrome, ataxia–pancytopenia syndrome and myelodysplasia and leukemia syndrome with monosomy 7 syndrome. Germline gain-of-function mutations increase SAMD9 or SAMD9L’s normal antiproliferative effect. This causes pancytopenia and generally restricted growth and/or specific organ hypoplasia in non-hematopoietic tissues. In blood cells, additional somatic aberrations that reverse the germline mutation’s effect, and give rise to the clonal expansion of cells with reduced or no antiproliferative effect of SAMD9 or SAMD9L include complete or partial chromosome 7 loss or loss-of-function mutations in SAMD9 or SAMD9L. Furthermore, the complete or partial loss of chromosome 7q may cause myelodysplastic syndrome in these patients. SAMD9 mutations appear to associate with a more severe disease phenotype, including intrauterine growth restriction, developmental delay and hypoplasia of adrenal glands, testes, ovaries or thymus, and most reported patients died in infancy or early childhood due to infections, anemia and/or hemorrhages. SAMD9L mutations have been reported in a few families with balance problems and nystagmus due to cerebellar atrophy, and may lead to similar hematological disease as seen in SAMD9 mutation carriers, from early childhood to adult years. We review the clinical features of these syndromes, discuss the underlying biology, and interpret the genetic findings in some of the affected family members. We provide expert-based recommendations regarding diagnosis, follow-up, and treatment of mutation carriers.
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| 9. |
- Eliasson, Pernilla, et al.
(författare)
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Hypoxia mediates low cell-cycle activity and increases the proportion of long-term reconstituting hematopoietic stem cells during in vitro culture
- 2010
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Ingår i: Experimental Hematology. - : Elsevier. - 0301-472X .- 1873-2399. ; 38:4, s. 301-310
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Recent evidence suggests that hematopoietic stem cells (HSCs) in the bone marrow (BM) are located in areas where the environment is hypoxic. Although previous studies have demonstrated positive effects by hypoxia, its role in HSC maintenance has not been fully elucidated, neither has the molecular mechanisms been delineated. Here, we have investigated the consequence of in vitro incubation of HSCs in hypoxia prior to transplantation and analyzed the role of hypoxia-inducible factor (HIF)-1 alpha. Materials and Methods. HSC and progenitor populations isolated from mouse BM were cultured in 20% or 1% O-2, and analyzed for effects on cell cycle, expression of cyclin-dependent kinase inhibitors genes, and reconstituting ability to lethally irradiated mice. The involvement of HIF-1 alpha was studied using methods of protein stabilization and gene silencing. Results. When long-term FLT3(-)CD34(-)Lin(-)Sca-1(+)c-Kit(+) (LSK) cells were cultured in hypoxia, cell numbers were significantly reduced in comparison to normoxia. This was due to a decrease in proliferation and more cells accumulating in G(0). Moreover, the proportion of HSCs with long-term engraftment potential was increased. Whereas expression of the cyclin-dependent kinase inhibitor genes p21(cip1), p27(Kip1), and p57(Kip2) increased in LSK cells by hypoxia, only p21(cip1) was upregulated in FLT3(-)CD34(-)LSK cells. We could demonstrate that expression of p27(KiP1) and p57(Kip2) was dependent of HIF-1 alpha. Surprisingly, overexpression of constitutively active HIF-1 alpha or treatment with the HIF stabilizer agent FG-4497 led to a reduction in HSC reconstituting ability. Conclusions. Our results imply that hypoxia, in part via HIF-1 alpha, maintains HSCs by decreasing proliferation and favoring quiescence.
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| 10. |
- Engert, Andreas, et al.
(författare)
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The European Hematology Association Roadmap for European Hematology Research : a consensus document
- 2016
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Ingår i: Haematologica. - Pavia, Italy : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 101:2, s. 115-208
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Tidskriftsartikel (refereegranskat)abstract
- The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at (sic)23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine 'sections' in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients.
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| 11. |
- Engvall, Marie, et al.
(författare)
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Familial platelet disorder due to germline exonic deletions in RUNX1 : a diagnostic challenge with distinct alterations of the transcript isoform equilibrium
- 2022
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Ingår i: Leukemia and Lymphoma. - : Taylor & Francis Group. - 1042-8194 .- 1029-2403. ; 63:10, s. 2311-2320
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Tidskriftsartikel (refereegranskat)abstract
- Germline pathogenic variants in RUNX1 are associated with familial platelet disorder with predisposition to myeloid malignancies (FPD/MM) with intragenic deletions in RUNX1 accounting for almost 7% of all reported variants. We present two new pedigrees with FPD/MM carrying two different germline RUNX1 intragenic deletions. The aforementioned deletions encompass exons 1-2 and 9-10 respectively, with the exon 9-10 deletion being previously unreported. RNA sequencing of patients carrying the exon 9-10 deletion revealed a fusion with LINC00160 resulting in a change in the 3 ' sequence of RUNX1. Expression analysis of the transcript isoform demonstrated altered RUNX1a/b/c ratios in carriers from both families compared to controls. Our data provide evidence on the impact of intragenic RUNX1 deletions on transcript isoform expression and highlight the importance of routinely performing copy number variant analysis in patients with suspected MM with germline predisposition.
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| 12. |
- Eriksson, Mia, et al.
(författare)
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Agonistic targeting of TLR1/TLR2 induces p38 MAPK-dependent apoptosis and NFκB-dependent differentiation of AML cells
- 2017
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 1:23, s. 2046-2057
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Tidskriftsartikel (refereegranskat)abstract
- Acute myeloid leukemia (AML) is associated with poor survival, and there is a strong need to identify disease vulnerabilities that might reveal new treatment opportunities. Here, we found that Toll-like receptor 1 (TLR1) and TLR2 are upregulated on primary AML CD34+CD38-cells relative to corresponding normal bone marrow cells. Activating the TLR1/TLR2 complex by the agonist Pam3CSK4 inMLL-AF9-driven human AML resulted in induction of apoptosis by p38 MAPK-dependent activation of Caspase 3 and myeloid differentiation in a NFκB-dependent manner. By using murineTrp53 -/- MLL-AF9AML cells, we demonstrate that p53 is dispensable for Pam3CSK4-induced apoptosis and differentiation. Moreover, murineAML1-ETO9a-driven AML cells also were forced into apoptosis and differentiation on TLR1/TLR2 activation, demonstrating that the antileukemic effects observed were not confined toMLL-rearranged AML. We further evaluated whether Pam3CSK4 would exhibit selective antileukemic effects. Ex vivo Pam3CSK4 treatment inhibited murine and human leukemia-initiating cells, whereas murine normal hematopoietic stem and progenitor cells (HSPCs) were relatively less affected. Consistent with these findings, primary human AML cells across several genetic subtypes of AML were more vulnerable for TLR1/TLR2 activation relative to normal human HSPCs. In theMLL-AF9AML mouse model, treatment with Pam3CSK4 provided proof of concept for in vivo therapeutic efficacy. Our results demonstrate that TLR1 and TLR2 are upregulated on primitive AML cells and that agonistic targeting of TLR1/TLR2 forces AML cells into apoptosis by p38 MAPK-dependent activation of Caspase 3, and differentiation by activating NFκB, thus revealing a new putative strategy for therapeutically targeting AML cells.
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| 13. |
- Gorcenco, Sorina, et al.
(författare)
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Ataxia-pancytopenia syndrome with SAMD9L mutations
- 2017
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Ingår i: Neurology: Genetics. - 2376-7839. ; 3:5
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We describe the neurologic, neuroradiologic, and ophthalmologic phenotype of 1 Swedish and 1 Finnish family with autosomal dominant ataxia-pancytopenia (ATXPC) syndrome and SAMD9L mutations.METHODS: Members of these families with germline SAMD9L c.2956C>T, p.Arg986Cys, or c.2672T>C, p.Ile891Thr mutations underwent structured interviews and neurologic and ophthalmologic examinations. Neuroimaging was performed, and medical records were reviewed. Previous publications on SAMD9L-ATXPC were reviewed.RESULTS: Twelve individuals in both families were affected clinically. All mutation carriers examined had balance impairment, although severity was very variable. All but 1 had nystagmus, and all but 1 had pyramidal tract signs. Neurologic features were generally present from childhood on and progressed slowly. Two adult patients, who experienced increasing clumsiness, glare, and difficulties with gaze fixation, had paracentral retinal dysfunction verified by multifocal electroretinography. Brain MRI showed early, marked cerebellar atrophy in most carriers and variable cerebral periventricular white matter T2 hyperintensities. Two children were treated with hematopoietic stem cell transplantation for hematologic malignancies, and the neurologic symptoms of one of these worsened after treatment. Three affected individuals had attention deficit hyperactivity disorder or cognitive problems. Retinal dysfunction was not previously reported in individuals with ATXPC.CONCLUSIONS: The neurologic phenotype of this syndrome is defined by balance or gait impairment, nystagmus, hyperreflexia in the lower limbs and, frequently, marked cerebellar atrophy. Paracentral retinal dysfunction may contribute to glare, reading problems, and clumsiness. Timely diagnosis of ATXPC is important to address the risk for severe hemorrhage, infection, and hematologic malignancies inherent in this syndrome; regular hematologic follow-up might be beneficial.
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| 14. |
- Hayden, Patrick J., et al.
(författare)
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Conditioning-based outcomes after allogeneic transplantation for myeloma following a prior autologous transplant (1991-2012) on behalf of EBMT CMWP
- 2020
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Ingår i: European Journal of Haematology. - : WILEY. - 0902-4441 .- 1600-0609.
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to compare the effect of the intensity of conditioning approaches used in allogeneic transplantation in myeloma-reduced intensity conditioning (RIC), non-myeloablative (NMA), myeloablative conditioning (MAC) or Auto-AlloHCT-on outcomes in patients who had had a prior autologous transplant. Methods A retrospective analysis of the EBMT database (1991-2012) was performed. Results A total of 344 patients aged between 40 and 60 years at the time of alloHCT were identified: 169 RIC, 69 NMA, 65 MAC and 41 Auto-Allo transplants. At a median follow-up of 54 months, the probabilities of overall survival (OS) at 5 years were 39% (95% CI 31%-47%), 45% (95% CI 32%-57%), 19% (95% CI 6%-32%) and 34% (95% CI 17%-51%), respectively. Status at allogeneic HCT other than CR or PR conferred a 70% higher risk of death and a 40% higher risk of relapse. OS was markedly lower in the MAC group (P = .004). MAC alloHCT was associated with a higher risk of death than RIC alloHCT until 2002 (HR = 4.1, P amp;lt; .001) but not after 2002 (HR = 1.2, P = .276). Conclusion From 1991 to 2002, MAC was associated with poorer OS. Between 2003 and 2012, there were no significant differences in outcomes based on these different approaches.
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| 15. |
- Hellström Lindberg, Eva, et al.
(författare)
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Precisionsmedicin standard vid flera hematologiska sjukdomar
- 2021
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Ingår i: Lakartidningen. - 0023-7205. ; 118
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Tidskriftsartikel (refereegranskat)abstract
- Precision diagnostics and therapy have been implemented rather early in clinical hematology due to the easy accessibility of blood and bone marrow, allowing not only for consecutive genetic analysis at diagnosis, remission and relapse, but also for culturing these cells and testing new drugs in vitro. One contributing factor has also been the relatively low number of »driver« mutations in hematologic malignancies and that some of them are gain of function mutations that are relatively easy to target by drugs. Examples of this development are ABL1-, JAK2-, and FLT3-inhibitors for the treatment of chronic myeloid leukemia, myeloproliferative neoplasms, and acute myeloid leukemia, respectively. More recently, gene panel sequencing has been introduced in clinical routine to identify genetic alterations with diagnostic, prognostic and predictive impact, and more sensitive techniques to monitor minimal residual disease are emerging. Whole genome and transcriptome sequencing are currently evaluated as the next diagnostic tool. Finally, a large number of targeted therapies are currently under development and/or undergoing clinical trials.
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| 16. |
- Hellström Lindberg, Eva, et al.
(författare)
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Precisionsmedicin standard vid flera hematologiska sjukdomar : Genpanelsekvensering viktig för diagnos och riktad behandling [Precision diagnostics and therapy in hematological malignancies]
- 2021
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Ingår i: Läkartidningen. - : Sveriges Läkarförbund. - 0023-7205 .- 1652-7518. ; 118
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Forskningsöversikt (refereegranskat)abstract
- Precision diagnostics and therapy have been implemented rather early in clinical hematology due to the easy accessibility of blood and bone marrow, allowing not only for consecutive genetic analysis at diagnosis, remission and relapse, but also for culturing these cells and testing new drugs in vitro. One contributing factor has also been the relatively low number of »driver« mutations in hematologic malignancies and that some of them are gain of function mutations that are relatively easy to target by drugs. Examples of this development are ABL1-, JAK2-, and FLT3-inhibitors for the treatment of chronic myeloid leukemia, myeloproliferative neoplasms, and acute myeloid leukemia, respectively. More recently, gene panel sequencing has been introduced in clinical routine to identify genetic alterations with diagnostic, prognostic and predictive impact, and more sensitive techniques to monitor minimal residual disease are emerging. Whole genome and transcriptome sequencing are currently evaluated as the next diagnostic tool. Finally, a large number of targeted therapies are currently under development and/or undergoing clinical trials.
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| 17. |
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| 18. |
- Jaako, P., et al.
(författare)
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Induction of the 5S RNP-Mdm2-p53 ribosomal stress pathway delays the initiation but fails to eradicate established murine acute myeloid leukemia
- 2017
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Ingår i: Leukemia. - : NATURE PUBLISHING GROUP. - 0887-6924 .- 1476-5551. ; 31:1, s. 213-221
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Tidskriftsartikel (refereegranskat)abstract
- Mutations resulting in constitutive activation of signaling pathways that regulate ribosome biogenesis are among the most common genetic events in acute myeloid leukemia (AML). However, whether ribosome biogenesis presents as a therapeutic target to treat AML remains unexplored. Perturbations in ribosome biogenesis trigger the 5S ribonucleoprotein particle (RNP)-Mdm2-p53 ribosomal stress pathway, and induction of this pathway has been shown to have therapeutic efficacy in Myc-driven lymphoma. In the current study we address the physiological and therapeutic role of the 5S RNP-Mdm2-p53 pathway in AML. By utilizing mice that have defective ribosome biogenesis due to downregulation of ribosomal protein S19 (Rps19), we demonstrate that induction of the 5S RNP-Mdm2-p53 pathway significantly delays the initiation of AML. However, even a severe Rps19 deficiency that normally results in acute bone marrow failure has no consistent efficacy on already established disease. Finally, by using mice that harbor a mutation in the Mdm2 gene disrupting its binding to 5S RNP, we show that loss of the 5S RNP-Mdm2-p53 pathway is dispensable for development of AML. Our study suggests that induction of the 5S RNP-Mdm2-p53 ribosomal stress pathway holds limited potential as a single-agent therapy in the treatment of AML.
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| 19. |
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| 20. |
- Juliusson, Gunnar, et al.
(författare)
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The prognostic impact of FLT3-ITD and NPM1 mutation in adult AML is age-dependent in the population-based setting
- 2020
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Ingår i: Blood Advances. - : AMER SOC HEMATOLOGY. - 2473-9529 .- 2473-9537. ; 4:6, s. 1094-1101
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Tidskriftsartikel (refereegranskat)abstract
- In acute myeloid leukemia (AML) FLT3 internal tandem duplication (ITD) and nucleophosmin 1 (NPM1) mutations provide prognostic information with clinical relevance through choice of treatment, but the effect of age and sex on these molecular markers has not been evaluated. The Swedish AML Registry contains data on FLT3-ITD and NPM1 mutations dating to 2007, and 1570 adult patients younger than 75 years, excluding acute promyelocytic leukemia, had molecular results reported. Females more often had FLT3(ITD) and/or NPM1(mut) (FLT3(ITD) : female, 29%; male, 22% [P - .00151; NPM1(mut) : female, 36%; male, 27% [P < .0001]), and more males were double negative (female, 53%; male, 64%; P < .0001). Patients with FLT3(ITD) were younger than those without (59 vs 62 years; P = .023), in contrast to patients with NPM1(mut) (62 vs 60 years; P = .059). Interestingly, their prognostic effect had a strong dependence on age: FLT3(ITD) indicated poor survival in younger patients (<60 years; P = .00003), but had no effect in older patients (60-74 years; P = .5), whereas NPM1(mut) indicated better survival in older patients (P = .00002), but not in younger patients (P = .95). In FLT3(ITD)/NPM1(mut) patients, the survival was less dependent on age than in the other molecular subsets. These findings are likely to have clinical relevance for risk grouping, study design, and choice of therapy.
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| 21. |
- Järås, Marcus, et al.
(författare)
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Expression of P190 and P210 BCR/ABL1 in normal human CD34(+) cells induces similar gene expression profiles and results in a STAT5-dependent expansion of the erythroid lineage
- 2009
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 37:3, s. 367-375
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The P190 and P210 BCR/ABL1 fusion genes are mainly associated with different types of hematologic malignancies, but it is presently unclear whether they are functionally different following expression in primitive human hematopoietic cells. Materials and Methods. We investigated and systematically compared the effects of retroviral P190 BCR/ABL1 and P210 BCR/ABL1 expression on cell proliferation, differentiation, and global gene expression in human CD34(+) cells from cord blood. Results. Expression of either P190 BCR/ABL1 or P210 BCR/ABL1 resulted in expansion of erythroid cells and stimulated erythropoietin-independent burst-forming unit-erythroid colony formation. By using a lentiviral anti-signal transducer and activator of transcription 5 (STAT5) short-hairpin RNA, we found that both P190 BCR/ABL1- and P210 BCR/ABL1-induced erythroid cell expansion were STAT5-dependent. Under in vitro conditions favoring B-cell differentiation, neither P190 nor P210 BCR/ABL1-expressing cells formed detectable levels of CD19-positive cells. Gene expression profiling revealed that P190 BCR/ABL1 and P210 BCR/ABL1 induced almost identical gene expression profiles. Conclusions. Our data suggest that the early cellular and transcriptional effects of P190 BCR/ABL1 and P210 BCR/ABL1 expression are very similar when they are expressed in the same human progenitor cell population, and that STAT5 is an important regulator of BCR/ABL1-induced erythroid cell expansion. (C) 2009 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.
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| 22. |
- Kharazi, Shabnam, et al.
(författare)
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Impact of gene dosage, loss of wild-type allele, and FLT3 ligand on Flt3-ITD-induced myeloproliferation
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 118:13, s. 3613-3621
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Tidskriftsartikel (refereegranskat)abstract
- Acquisition of homozygous activating growth factor receptor mutations might accelerate cancer progression through a simple gene-dosage effect. Internal tandem duplications (ITDs) of FLT3 occur in approximately 25% cases of acute myeloid leukemia and induce ligand-independent constitutive signaling. Homozygous FLT3-ITDs confer an adverse prognosis and are frequently detected at relapse. Using a mouse knockin model of Flt3-internal tandem duplication (Flt3-ITD)-induced myeloproliferation, we herein demonstrate that the enhanced myeloid phenotype and expansion of granulocyte-monocyte and primitive Lin(-)Sca1(+)c-Kit(+) progenitors in Flt3-ITD homozygous mice can in part be mediated through the loss of the second wild-type allele. Further, whereas autocrine FLT3 ligand production has been implicated in FLT3-ITD myeloid malignancies and resistance to FLT3 inhibitors, we demonstrate here that the mouse Flt3(ITD/ITD) myeloid phenotype is FLT3 ligand-independent. (Blood. 2011; 118(13):3613-3621)
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| 23. |
- Lazarevic, Vladimir Lj, et al.
(författare)
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Acute myeloid leukemia in very old patients
- 2018
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Ingår i: Haematologica. - Pavia, Italy : Fondazione Ferrata Storti. - 0390-6078 .- 1592-8721. ; 103:12, s. E578-E580
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
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| 24. |
- Lindholm, C., et al.
(författare)
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Failure to reach hematopoietic allogenic stem cell transplantation in patients with myelodysplastic syndromes planned for transplantation : a population-based study
- 2022
-
Ingår i: Bone Marrow Transplantation. - : Springer Nature. - 0268-3369 .- 1476-5365. ; 57, s. 598-606
-
Tidskriftsartikel (refereegranskat)abstract
- The only potential cure for patients with myelodysplastic syndrome (MDS) is allogeneic hematopoietic stem cell transplantation (HCT). However, a proportion of patients who are HCT candidates do not finally get transplanted. This population-based study aimed to characterize HCT candidates were attempting to reach HCT fail and to identify causes and risk factors for failure. Data were collected from (1) the national Swedish registry, enrolling 291 transplant candidates between 2009-2018, and (2) Karolinska University Hospital, enrolling 131 transplantation candidates between 2000 and 2018. Twenty-five % (nation-wide) and 22% (Karolinska) failed to reach HCT. Reasons for failure to reach HCT were progressive and refractory disease (47%), no donor identified (22%), identification of comorbidity (18%), and infectious complications (14%). Factors associated with failure to reach HCT were IPSS-R cytogenetic risk-group very poor, mixed MDS/MPN disease, low blast count (0-4.9%), and low hemoglobin levels (<= 7.9 g/dL). Transplanted patients had a longer overall survival (OS) compared to patients who failed to reach transplantation (83 months versus 14 months; p < 0.001). The survival advantage was seen for the IPSS-R risk groups intermediate, high, and very high. This study demonstrated that a high proportion of HCT-candidates fail to reach HCT and underlines the difficulties associated with bridging MDS patients to HCT.
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| 25. |
- Lübking, Anna, et al.
(författare)
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Young woman with mild bone marrow dysplasia, GATA2 and ASXL1 mutation treated with allogeneic hematopoietic stem cell transplantation
- 2015
-
Ingår i: Leukemia Research Reports. - : Elsevier. - 2213-0489. ; 4:2, s. 72-75
-
Tidskriftsartikel (refereegranskat)abstract
- Heterozygous mutations in GATA2 underlie different syndromes, previously described as monocytopenia and mycobacterial avium complex infection (MonoMAC); dendritic cell, monocytes, B- and NK lymphocytes deficiency (DCML); lymphedema, deafness and myelodysplasia (Emberger syndrome) and familiar myelodysplastic syndrome/acute myeloid leukemia (MDS / AML). Onset and severity of clinical symptoms vary and preceding cytopenias are not always present. We describe a case of symptomatic DCML deficiency and rather discrete bone marrow findings due to GATA2 mutation. Exome sequencing revealed a somatic ASXL1 mutation and the patient underwent allogeneic stem cell transplantation successfully. © 2015.
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| 26. |
- Malinski, Bartosz, et al.
(författare)
-
Novel pathological variants of NHP2 affect N-terminal domain flexibility, protein stability, H/ACA Ribonucleoprotein (RNP) complex formation and telomerase activity
- 2023
-
Ingår i: Human Molecular Genetics. - : OXFORD UNIV PRESS. - 0964-6906 .- 1460-2083. ; 32:19, s. 2901-2912
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Tidskriftsartikel (refereegranskat)abstract
- Telomere biology disorders (TBDs) are characterized by short telomeres, premature aging, bone marrow failure and cancer predisposition. Germline mutations in NHP2, encoding for one component of the telomerase cofactor H/ACA RNA binding complex together with Dyskerin, NOP10 and GAR1, have been previously reported in rare cases of TBDs. Here, we report two novel NHP2 variants (NHP2-A39T and NHP2-T44M) identified in a compound heterozygous patient affected by premature aging, bone marrow failure/myelodysplastic syndrome and gastric cancer. Although still able to support cell viability, both variants reduce the levels of hTR, the telomerase RNA component, and telomerase activity, expanding the panel of NHP2 pathological variants. Furthermore, both variants fail to be incorporated in the H/ACA RNA binding complex when in competition with wild-type endogenous NHP2, and the lack of incorporation causes their drastic proteasomal degradation. By RoseTTAFold prediction followed by molecular dynamics simulations, we reveal a dramatic distortion of residues 33-41, which normally position on top of the NHP2 core, as the main defect of NHP2-A39T, and high flexibility and the misplacement of the N-terminal region (residues 1-24) in NHP2-T44M and, to a lower degree, in NHP2-A39T. Because deletion of amino acids 2-24 causes a reduction in NHP2 levels only in the presence of wild-type NHP2, while deletion of amino acids 2-38 completely disrupts NHP2 stability, we propose that the two variants are mis-incorporated into the H/ACA binding complex due to the altered dynamics of the first 23 amino acids and/or the distortion of the residues 25-41 loop.
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| 27. |
- Martin Gonzalez, Javier, et al.
(författare)
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A new genetic tool to improve immune-compromised mouse models : Derivation and CRISPR/Cas9-mediated targeting of NRG embryonic stem cell lines
- 2018
-
Ingår i: Genesis. - : Wiley. - 1526-968X .- 1526-954X. ; 56:9
-
Tidskriftsartikel (refereegranskat)abstract
- Development of human hematopoietic stem cells and differentiation of embryonic stem (ES) cells/induced pluripotent stem (iPS) cells to hematopoietic stem cells are poorly understood. NOD (Non-obese diabetic)-derived mouse strains, such as NSG (NOD-Scid-il2Rg) or NRG (NOD-Rag1-il2Rg), are the best available models for studying the function of fetal and adult human hematopoietic cells as well as ES/iPS cell-derived hematopoietic stem cells. Unfortunately, engraftment of human hematopoietic stem cells is very variable in these models. Introduction of additional permissive mutations into these complex genetic backgrounds of the NRG/NSG mice by natural breeding is a very demanding task in terms of time and resources. Specifically, since the genetic elements defining the NSG/NRG phenotypes have not yet been fully characterized, intense backcrossing is required to ensure transmission of the full phenotype. Here we describe the derivation of embryonic stem cell (ESC) lines from NRG pre-implantation embryos generated by in vitro fertilization followed by the CRISPR/CAS9 targeting of the Gata-2 locus. After injection into morula stage embryos, cells from three tested lines gave rise to chimeric adult mice showing high contribution of the ESCs (70%–100%), assessed by coat color. Moreover, these lines have been successfully targeted using Cas9/CRISPR technology, and the mutant cells have been shown to remain germ line competent. Therefore, these new NRG ESC lines combined with genome editing nucleases bring a powerful genetic tool that facilitates the generation of new NOD-based mouse models with the aim to improve the existing xenograft models.
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| 28. |
- Miharada, Kenichi, et al.
(författare)
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Cripto Regulates Hematopoietic Stem Cells as a Hypoxic-Niche-Related Factor through Cell Surface Receptor GRP78.
- 2011
-
Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 9:4, s. 330-344
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoietic stem cells (HSCs) are maintained in hypoxic niches in endosteal regions of bones. Here we demonstrate that Cripto and its receptor GRP78 are important regulators of HSCs in the niche. Flow cytometry analyses revealed two distinct subpopulations of CD34(-)KSL cells based on the expression of GRP78, and these populations showed different reconstitution potential in transplantation assays. GRP78(+)HSCs mainly reside in the endosteal area, are more hypoxic, and exhibit a lower mitochondrial potential, and their HSC capacity was maintained in vitro by Cripto through induction of higher glycolytic activity. Additionally, HIF-1α KO mice have decreased numbers of GRP78(+)HSCs and reduced expression of Cripto in the endosteal niche. Furthermore, blocking GRP78 induced a movement of HSCs from the endosteal to the central marrow area. These data suggest that Cripto/GRP78 signaling is an important pathway that regulates HSC quiescence and maintains HSCs in hypoxia as an intermediary of HIF-1α.
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| 29. |
- Miharada, Kenichi, et al.
(författare)
-
Hematopoietic stem cells are regulated by Cripto, as an intermediary of HIF-1α in the hypoxic bone marrow niche.
- 2012
-
Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923. ; 1266:1, s. 55-62
-
Tidskriftsartikel (refereegranskat)abstract
- Cripto has been known as an embryonic stem (ES)- or tumor-related soluble/cell membrane protein. In this study, we demonstrated that Cripto has a role as an important regulatory factor for hematopoietic stem cells (HSCs). Recombinant Cripto sustained the reconstitution ability of HSCs in vitro. Flow cytometry analysis uncovered that GRP78, one of the candidate receptors for Cripto, was expressed on a subset of HSCs and could distinguish dormant/myeloid-biased HSCs and active/lymphoid-biased HSCs. Cripto is expressed in hypoxic endosteal niche cells where GRP78(+) HSCs mainly reside. Proteomics analysis revealed that Cripto-GRP78 binding stimulates glycolytic metabolism-related proteins and results in lower mitochondrial potential in HSCs. Furthermore, conditional knockout mice for HIF-1α, a master regulator of hypoxic responses, showed reduced Cripto expression and decreased GRP78(+) HSCs in the endosteal niche area. Thus, Cripto-GRP78 is a novel HSC regulatory signal mainly working in the hypoxic niche.
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| 30. |
- Mogilenko, Denis A., et al.
(författare)
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Metabolic and Innate Immune Cues Merge into a Specific Inflammatory Response via the UPR
- 2019
-
Ingår i: Cell. - : CELL PRESS. - 0092-8674 .- 1097-4172. ; 177:5, s. 1201-
-
Tidskriftsartikel (refereegranskat)abstract
- Innate immune responses are intricately linked with intracellular metabolism of myeloid cells. Toll-like receptor (TLR) stimulation shifts intracellular metabolism toward glycolysis, while anti-inflammatory signals depend on enhanced mitochondrial respiration. How exogenous metabolic signals affect the immune response is unknown. We demonstrate that TLR-dependent responses of dendritic cells (DCs) are exacerbated by a high-fatty-acid (FA) metabolic environment. FAs suppress the TLR-induced hexokinase activity and perturb tricarboxylic acid cycle metabolism. These metabolic changes enhance mitochondria! reactive oxygen species (mtROS) production and, in turn, the unfolded protein response (UPR), leading to a distinct transcriptomic signature with IL-23 as hallmark. Interestingly, chemical or genetic suppression of glycolysis was sufficient to induce this specific immune response. Conversely, reducing mtROS production or DC-specific deficiency in XBP1 attenuated IL-23 expression and skin inflammation in an IL-23-dependent model of psoriasis. Thus, fine-tuning of innate immunity depends on optimization of metabolic demands and minimization of mtROS-induced UPR.
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| 31. |
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| 32. |
- Niebuhr, Birte, et al.
(författare)
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Gatekeeper function of the RUNX1 transcription factor in acute leukemia
- 2008
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Ingår i: Blood Cells, Molecules & Diseases. - : Elsevier BV. - 1096-0961 .- 1079-9796. ; 40:2, s. 211-218
-
Tidskriftsartikel (refereegranskat)abstract
- The RUNX1 gene encodes the alpha subunit of the core binding factor (CBF) and is a common target of genetic mutations in acute leukemia. We propose that RUNX1 is a gatekeeper gene, the disruption of which leads to the exodus of a subset of hematopoietic progenitors with increased self-renewal potential from the normal environmental controls of homeostasis. This pool of "escaped" cells is the target of secondary mutations, accumulating over time to induce the aggressive manifestation of acute leukemia. Evidence from patient and animal studies supports the concept that RUNX1 Mutations are the initiating event in different leukemia subtypes, but also suggests that diverse mechanisms are used to subvert RUNX1 function. One common result is the inhibition of differentiation-but its effect impinges on different lineages and stages of differentiation, depending on the mutation or fusion partner. A number of different approaches have led to the identification of secondary events that lead to the overt acute phase; however, the majority is unknown. Finally, the concept of the "leukemia stern cell" and its therapeutic importance is discussed in light of the RUNX1 gatekeeper function.
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| 33. |
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| 34. |
- Nilsson, Alexandra Rundberg, et al.
(författare)
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IRF1 regulates self-renewal and stress-responsiveness to support hematopoietic stem cell maintenance
- 2023
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Inflammatory mediators induce emergency myelopoiesis and cycling of adult hematopoietic stem cells (HSCs) through incompletely understood mechanisms. To suppress the unwanted effects of inflammation and preserve its beneficial outcomes, the mechanisms by which inflammation affects hematopoiesis need to be fully elucidated. Rather than focusing on specific inflammatory stimuli, we here investigated the role of transcription factor Interferon (IFN) regulatory factor 1 (IRF1), which receives input from several inflammatory signaling pathways. We identify IRF1 as a master HSC regulator. IRF1 loss impairs HSC self-renewal, increases stress-induced cell cycle activation, and confers apoptosis resistance. Transcriptomic analysis revealed an aged, inflammatory signature devoid of IFN signaling with reduced megakaryocytic/erythroid priming and antigen presentation in IRF1-deficient HSCs. Finally, we conducted IRF1-based AML patient stratification to identify groups with distinct proliferative, survival and differentiation features, overlapping with our murine HSC results. Our findings position IRF1 as a pivotal regulator of HSC preservation and stress-induced responses.Competing Interest StatementThe authors have declared no competing interest.
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| 35. |
- Nilsson, Christer, et al.
(författare)
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Characterization of therapy-related acute myeloid leukemia : increasing incidence and prognostic implications
- 2023
-
Ingår i: Haematologica. - : Ferrata Storti Foundation. - 0390-6078 .- 1592-8721. ; 108:4, s. 1015-1025
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of therapy-related AML (t-AML) are usually performed in selected cohorts and reliable incidence rates are lacking. In this study, we characterized, defined the incidence over time and studied prognostic implications in all t-AML patients diagnosed in Sweden between 1997 and 2015. Data were retrieved from nationwide population-based registries. In total, 6,779 AML patients were included in the study, of whom 686 (10%) had t-AML. The median age for t-AML was 71 years and 392 (57%) patients were females. During the study period, the incidence of t-AML almost doubled with a yearly increase in t-AML of 4.5% (95% confidence interval: 2.8%-6.2%), which contributed significantly to the general increase in AML incidence over the study period. t-AML solidly constituted over 10% of all AML cases during the later period of the study. Primary diagnoses with the largest increase in incidence and decrease in mortality rate during the study period (i.e., breast and prostate cancer) contributed significantly to the increased incidence of t-AML. In multivariable analysis, t-AML was associated with poorer outcome in cytogenetically intermediate-and adverse-risk cases but t-AML had no significant impact on outcome in favorable-risk AML, including core binding leukemias, acute promyelocytic leukemia and AML with mutated NPM1 without FLT3-ITD. We conclude that there is a strong increase in incidence in t-AML over time and that t-AML constitutes a successively larger proportion of the AML cases. Furthermore, we conclude that t-AML confers a poor prognosis in cytogenetically intermediate-and adverse-risk, but not in favorable-risk AML.
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| 36. |
- Orsmark-Pietras, Christina, et al.
(författare)
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Clinical and genomic characterization of patients diagnosed with the provisional entity acute myeloid leukemia with BCR-ABL1, a Swedish population-based study
- 2021
-
Ingår i: Genes, Chromosomes and Cancer. - : Wiley-Liss Inc.. - 1045-2257 .- 1098-2264. ; 60:6, s. 426-433
-
Tidskriftsartikel (refereegranskat)abstract
- Acute myeloid leukemia (AML) with t(9;22)(q34;q11), also known as AML with BCR-ABL1, is a rare, provisional entity in the WHO 2016 classification and is considered a high-risk disease according to the European LeukemiaNet 2017 risk stratification. We here present a retrospective, population-based study of this disease entity from the Swedish Acute Leukemia Registry. By strict clinical inclusion criteria we aimed to identify genetic markers further distinguishing AML with t(9;22) as a separate entity. Twenty-five patients were identified and next-generation sequencing using a 54-gene panel was performed in 21 cases. Interestingly, no mutations were found in NPM1, FLT3, or DNMT3A, three frequently mutated genes in AML. Instead, RUNX1 was the most commonly mutated gene, with aberrations present in 38% of the cases compared to around 10% in de novo AML. Additional mutations were identified in genes involved in RNA splicing (SRSF2, SF3B1) and chromatin regulation (ASXL1, STAG2, BCOR, BCORL1). Less frequently, mutations were found in IDH2, NRAS, TET2, and TP53. The mutational landscape exhibited a similar pattern as recently described in patients with chronic myeloid leukemia (CML) in myeloid blast crisis (BC). Despite the concomitant presence of BCR-ABL1 and RUNX1 mutations in our cohort, both features of high-risk AML, the RUNX1-mutated cases showed a superior overall survival compared to RUNX1 wildtype cases. Our results suggest that the molecular characteristics of AML with t(9;22)/BCR-ABL1 and CML in myeloid BC are similar and do not support a distinction of the two disease entities based on their underlying molecular alterations.
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| 37. |
- Pietras, Alexander, et al.
(författare)
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HIF-2 alpha maintains an undifferentiated state in neural crest-like human neuroblastoma tumor-initiating cells
- 2009
-
Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 106:39, s. 16805-16810
-
Tidskriftsartikel (refereegranskat)abstract
- High hypoxia-inducible factor-2 alpha (HIF-2 alpha) protein levels predict poor outcome in neuroblastoma, and hypoxia dedifferentiates cultured neuroblastoma cells toward a neural crest-like phenotype. Here, we identify HIF-2 alpha as a marker of normoxic neural crest-like neuroblastoma tumor-initiating/stem cells (TICs) isolated from patient bone marrows. Knockdown of HIF-2 alpha reduced VEGF expression and induced partial sympathetic neuronal differentiation when these TICs were grown in vitro under stem cell-promoting conditions. Xenograft tumors of HIF-2 alpha-silenced cells were widely necrotic, poorly vascularized, and resembled the bulk of tumor cells in clinical neuroblastomas by expressing additional sympathetic neuronal markers, whereas control tumors were immature, well-vascularized, and stroma-rich. Thus, HIF-2 alpha maintains an undifferentiated state of neuroblastoma TICs. Because low differentiation is associated with poor outcome and angiogenesis is crucial for tumor growth, HIF-2 alpha is an attractive target for neuroblastoma therapy.
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| 38. |
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| 39. |
- Quere, Ronan, et al.
(författare)
-
High levels of the adhesion molecule CD44 on leukemic cells generate acute myeloid leukemia relapse after withdrawal of the initial transforming event.
- 2011
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 25, s. 515-526
-
Tidskriftsartikel (refereegranskat)abstract
- Multiple genetic hits are detected in patients with acute myeloid leukemia (AML). To investigate this further, we developed a tetracycline-inducible mouse model of AML, in which the initial transforming event, overexpression of HOXA10, can be eliminated. Continuous overexpression of HOXA10 is required to generate AML in primary recipient mice, but is not essential for maintenance of the leukemia. Transplantation of AML to secondary recipients showed that in established leukemias, ∼80% of the leukemia-initiating cells (LICs) in bone marrow stopped proliferating upon withdrawal of HOXA10 overexpression. However, the population of LICs in primary recipients is heterogeneous, as ∼20% of the LICs induce leukemia in secondary recipients despite elimination of HOXA10-induced overexpression. Intrinsic genetic activation of several proto-oncogenes was observed in leukemic cells resistant to inactivation of the initial transformation event. Interestingly, high levels of the adhesion molecule CD44 on leukemic cells are essential to generate leukemia after removal of the primary event. This suggests that extrinsic niche-dependent factors are also involved in the host-dependent outgrowth of leukemias after withdrawal of HOXA10 overexpression event that initiates the leukemia.Leukemia advance online publication, 30 November 2010; doi:10.1038/leu.2010.281.
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| 40. |
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| 41. |
- Quere, Ronan, et al.
(författare)
-
SMAD4 binds HOXA9 in the cytoplasm and protects primitive hematopoietic cells against nuclear activation by HOXA9 and leukemia transformation.
- 2011
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 117, s. 5918-5930
-
Tidskriftsartikel (refereegranskat)abstract
- We studied leukemic stem cells (LSCs) in a Smad4(-/-) mouse model of acute myelogenous leukemia (AML) induced either by the HOXA9 gene or by the fusion oncogene NUP98-HOXA9. While HOXA9-SMAD4 complexes accumulate in the cytoplasm of normal hematopoietic stem- and progenitor cells (HSPCs) transduced with these oncogenes, there is no cytoplasmic accumulation of HOXA9 in Smad4(-/-) HSPCs and as a consequence increased levels of HOXA9 accumulate in the nucleus leading to increased immortalization in vitro. Loss of Smad4 accelerates the development of leukemia in vivo due to an increase in transformation of HSPCs. Therefore, the cytoplasmic binding of HOXA9 by SMAD4 is a mechanism to protect HOXA9-induced transformation of normal HSPCs. Since Smad4 is a potent tumor suppressor involved in growth control, we developed a strategy to modify the subcellular distribution of SMAD4. We successfully disrupted the interaction between HOXA9 and SMAD4 to activate the TGF-beta pathway and apoptosis, leading to a loss of LSCs. Together, these findings reveal a major role for Smad4 in the negative regulation of leukemia initiation and maintenance induced by HOXA9/NUP98-HOXA9 and provide strong evidence that antagonizing SMAD4 stabilization by these oncoproteins might be a promising novel therapeutic approach in leukemia.
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| 42. |
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| 43. |
- Reckzeh, Kristian, et al.
(författare)
-
Molecular and cellular effects of oncogene cooperation in a genetically accurate AML mouse model.
- 2012
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 26:7, s. 1527-1536
-
Tidskriftsartikel (refereegranskat)abstract
- Biallelic CEBPA mutations and FLT3 length mutations are frequently identified in human acute myeloid leukemia (AML) with normal cytogenetics. However, the molecular and cellular mechanisms of oncogene cooperation remain unclear due to a lack of disease models. We have generated an AML mouse model using knockin mouse strains to study cooperation of internal tandem duplication (ITD) mutation in the Flt3 gene with commonly observed C/EBPα mutations. This study provides evidence that FLT3 ITD cooperates in leukemogenesis by enhancing the generation of leukemia-initiating granulocyte-monocyte progenitors (GMP) otherwise prevented by a block in differentiation and skewed lineage priming induced by biallelic C/EBPα mutations. These cellular changes are accompanied by an upregulation of hematopoietic stem cell and STAT5 target genes. By gene expression analysis in premalignant populations we further show a role of FLT3 ITD in activating genes involved in survival/transformation and chemoresistance. Both multipotent progenitors (MPP) and GMP cells contain the potential to induce AML similar to corresponding cells in human AML samples showing that this model resembles human disease.Leukemia accepted article preview online, 9 February 2012; doi:10.1038/leu.2012.37.
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| 44. |
- Reckzeh, Kristian, et al.
(författare)
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Molecular mechanisms underlying deregulation of C/EBP alpha in acute myeloid leukemia
- 2010
-
Ingår i: International Journal of Hematology. - : Springer Science and Business Media LLC. - 0925-5710 .- 1865-3774. ; 91:4, s. 557-568
-
Forskningsöversikt (refereegranskat)abstract
- The CEBPA gene encodes a transcription factor protein that is crucial for granulocytic differentiation, regulation of myeloid gene expression and growth arrest. Mutations in one or both alleles of CEBPA are observed in about 10% of patients with acute myeloid leukemia (AML). Moreover, other genetic events associated with AML have been identified to deregulate C/EBP alpha expression and function at various levels. Recently developed mouse models that accurately mimic the genetic C/EBP alpha alterations in human AML demonstrate C/EBP alpha's gatekeeper function in the control of self-renewal and lineage commitment of hematopoietic stem cells (HSCs). Moreover, these studies indicate that CEBPA mutations affect HSCs in early leukemia development by inducing proliferation and limiting their lineage potential. However, the exact relationship between 'pre-leukemic' HCSs and those cells that finally initiate leukemia (leukemia-initiating cells) with disturbed differentiation and aberrant proliferation remains elusive. More research is needed to identify and characterize these functionally distinct populations and the exact role of the different genetic alterations in the process of leukemia initiation and maintenance.
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| 45. |
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| 46. |
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| 47. |
- Rehn, Matilda, et al.
(författare)
-
Hypoxic induction of vascular endothelial growth factor regulates erythropoiesis but not hematopoietic stem cell function in the fetal liver.
- 2014
-
Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 42:11, s. 941-944
-
Tidskriftsartikel (refereegranskat)abstract
- Hypoxia is an important factor in the hematopoietic stem cell (HSC) niche in the bone marrow, but whether it also plays a role in the regulation of fetal liver (FL) HSCs is unclear. Vascular endothelial growth factor A (VEGFA) is essential for adult HSC survival, and hypoxic induction of VEGFA in adult HSCs is required for proper function. Loss of hypoxia-regulated VEGFA expression increases the number of phenotypically defined hematopoietic stem and progenitor cells in the FL, but whether stem cell function is affected in FL HSCs has not, to our knowledge, been assessed. We show that fetal erythropoiesis is severely impaired when hypoxic induction of VEGFA is lacking. Fetal liver HSCs deficient for hypoxia-induced VEGFA expression have normal HSC function, arguing against a hypoxic FL HSC niche. However, after adaptation of FL HSCs to the bone marrow microenvironment, FL HSCs lose their function, as measured by serial transplantation.
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| 48. |
- Rehn, Matilda, et al.
(författare)
-
Hypoxic induction of vascular endothelial growth factor regulates murine hematopoietic stem cell function in the low-oxygenic niche.
- 2011
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 118:6, s. 1534-1543
-
Tidskriftsartikel (refereegranskat)abstract
- Hypoxia is emerging as an important characteristic of the hematopoietic stem cell (HSC) niche, but the molecular mechanisms contributing to quiescence, self-renewal, and survival remain elusive. Vascular endothelial growth factor A (VEGFA) is a key regulator of angiogenesis and hematopoiesis. Its expression is commonly regulated by hypoxia-inducible factors (HIF) that are functionally induced in low-oxygen conditions and that activate transcription by binding to hypoxia-response elements (HRE). Vegfa is indispensable for HSC survival, mediated by a cell-intrinsic, autocrine mechanism. We hypothesized that a hypoxic HSC microenvironment is required for maintenance or upregulation of Vegfa expression in HSCs and therefore crucial for HSC survival. We have tested this hypothesis in the mouse model Vegfa(δ/δ), where the HRE in the Vegfa promoter is mutated, preventing HIF binding. Vegfa expression was reduced in highly purified HSCs from Vegfa(δ/δ) mice, showing that HSCs reside in hypoxic areas. Loss of hypoxia-regulated Vegfa expression increases the numbers of phenotypically defined hematopoietic stem and progenitor cells. However, HSC function was clearly impaired when assessed in competitive transplantation assays. Our data provide further evidence that HSCs reside in a hypoxic microenvironment and demonstrate a novel way in which the hypoxic niche affects HSC fate, via the hypoxia-Vegfa axis.
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| 49. |
- Robin, Marie, et al.
(författare)
-
Antilymphocyte globulin for matched sibling donor transplantation in patients with myelofibrosis
- 2019
-
Ingår i: Haematologica. - : FERRATA STORTI FOUNDATION. - 0390-6078 .- 1592-8721. ; 104:6, s. 1230-1236
-
Tidskriftsartikel (refereegranskat)abstract
- The use of antihuman T-lymphocyte immunoglobulin in the setting of transplantation from an HLA-matched related donor is still much debated. Acute and chronic graft-versus-host disease are the main causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation in patients with myelofibrosis. The aim of this study was to evaluate the effect of antihuman T-lymphocyte immunoglobulin in a large cohort of patients with myelofibrosis (n= 287). The cumulative incidences of grade II-IV acute graft-versus-host disease among patients who were or were not given antihuman T-lymphocyte immunoglobulin were 26% and 41%, respectively. The corresponding incidences of chronic graft-versus-host disease were 52% and 55%, respectively. Non-adjusted overall survival, disease-free survival and non-relapse mortality rates were 55% versus 53%, 49% versus 45%, and 32% versus 31%, respectively, among the patients who were or were not given antihuman T-lymphocyte immunoglobulin. An adjusted model confirmed that the risk of acute graft-versus-host disease was lower following antihuman T-lymphocyte immunoglobulin (hazard ratio, 0.54; P= 0.010) while it did not decrease the risk of chronic graft-versus-host disease. The hazard ratios for overall survival and non-relapse mortality were 0.66 and 0.64, with P-values of 0.05 and 0.09, respectively. Antihuman T-lymphocyte immunoglobulin did not influence disease-free survival, graft-versus-host disease, relapse-free survival or relapse risk. In conclusion, in the setting of matched related transplantation in myelofibrosis patients, this study demonstrates that antihuman T-lymphocyte immunoglobulin decreases the risk of acute graft-versushost disease without increasing the risk of relapse.
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| 50. |
- Rodriguez-Zabala, Maria, et al.
(författare)
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Combined GLUT1 and OXPHOS inhibition eliminates acute myeloid leukemia cells by restraining their metabolic plasticity
- 2023
-
Ingår i: Blood Advances. - 2473-9529. ; 7:18, s. 5382-5395
-
Tidskriftsartikel (refereegranskat)abstract
- Acute myeloid leukemia (AML) is initiated and propagated by leukemia stem cells (LSCs), a self-renewing population of leukemia cells responsible for therapy resistance. Hence, there is an urgent need to identify new therapeutic opportunities targeting LSCs. Here, we performed an in vivo CRISPR knockout screen to identify potential therapeutic targets by interrogating cell surface dependencies of LSCs. The facilitated glucose transporter type 1 (GLUT1) emerged as a critical in vivo metabolic dependency for LSCs in a murine MLL::AF9–driven model of AML. GLUT1 disruption by genetic ablation or pharmacological inhibition led to suppression of leukemia progression and improved survival of mice that received transplantation with LSCs. Metabolic profiling revealed that Glut1 inhibition suppressed glycolysis, decreased levels of tricarboxylic acid cycle intermediates and increased the levels of amino acids. This metabolic reprogramming was accompanied by an increase in autophagic activity and apoptosis. Moreover, Glut1 disruption caused transcriptional, morphological, and immunophenotypic changes, consistent with differentiation of AML cells. Notably, dual inhibition of GLUT1 and oxidative phosphorylation (OXPHOS) exhibited synergistic antileukemic effects in the majority of tested primary AML patient samples through restraining of their metabolic plasticity. In particular, RUNX1-mutated primary leukemia cells displayed striking sensitivity to the combination treatment compared with normal CD34+ bone marrow and cord blood cells. Collectively, our study reveals a GLUT1 dependency of murine LSCs in the bone marrow microenvironment and demonstrates that dual inhibition of GLUT1 and OXPHOS is a promising therapeutic approach for AML.
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