Pegylated interferon alfa (pegIFN-α) can induce molecular remissions in patients with JAK2-V617F-positive myeloproliferative neoplasms (MPNs) by targeting long-term hematopoietic stem cells (LT-HSCs). Additional somatic mutations in genes regulating LT-HSC self-renewal, such as DNMT3A, have been reported to have poorer responses to pegIFN-α. We investigated whether DNMT3A loss leads to alterations in JAK2-V617F LT-HSC functions conferring resistance to pegIFN-α treatment in a mouse model of MPN and in hematopoietic progenitors from patients with MPN. Long-term treatment with pegIFN-α normalized blood parameters and reduced splenomegaly and JAK2-V617F chimerism in single-mutant JAK2-V617F (VF) mice. However, pegIFN-α in VF;Dnmt3aΔ/Δ (VF;DmΔ/Δ) mice worsened splenomegaly and failed to reduce JAK2-V617F chimerism. Furthermore, LT-HSCs from VF;DmΔ/Δ mice compared with VF were less prone to accumulate DNA damage and exit dormancy upon pegIFN-α treatment. RNA sequencing showed that IFN-α induced stronger upregulation of inflammatory pathways in LT-HSCs from VF;DmΔ/Δ than from VF mice, indicating that the resistance of VF;DmΔ/Δ LT-HSC was not due to failure in IFN-α signaling. Transplantations of bone marrow from pegIFN-α-treated VF;DmΔ/Δ mice gave rise to more aggressive disease in secondary and tertiary recipients. Liquid cultures of hematopoietic progenitors from patients with MPN with JAK2-V617F and DNMT3A mutation showed increased percentages of JAK2-V617F-positive colonies upon IFN-α exposure, whereas in patients with JAK2-V617F alone, the percentages of JAK2-V617F-positive colonies decreased or remained unchanged. PegIFN-α combined with 5-azacytidine only partially overcame resistance in VF;DmΔ/Δ mice. However, this combination strongly decreased the JAK2-mutant allele burden in mice carrying VF mutation only, showing potential to inflict substantial damage preferentially to the JAK2-mutant clone.

• MeSH
• buněčná sebeobnova MeSH
• chemorezistence * genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa * genetika   metabolismus   MeSH
• hematopoetické kmenové buňky * metabolismus   patologie   účinky léků   MeSH
• interferon alfa * farmakologie   MeSH
• Janus kinasa 2 * genetika   metabolismus   MeSH
• lidé MeSH
• myeloproliferativní poruchy * genetika   patologie   farmakoterapie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• polyethylenglykoly farmakologie   MeSH
• rekombinantní proteiny MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA methyltransferasa 3A * MeSH
• DNA-(cytosin-5-)methyltransferasa * MeSH
• DNMT3A protein, human MeSH Prohlížeč
• Dnmt3a protein, mouse MeSH Prohlížeč
• interferon alfa * MeSH
• JAK2 protein, human MeSH Prohlížeč
• Jak2 protein, mouse MeSH Prohlížeč
• Janus kinasa 2 * MeSH
• peginterferon alfa-2a MeSH Prohlížeč
• polyethylenglykoly MeSH
• rekombinantní proteiny MeSH

Transcription factor C/EBPα is a master regulator of myelopoiesis and its inactivation is associated with acute myeloid leukemia. Deregulation of C/EBPα by microRNAs during granulopoiesis or acute myeloid leukemia development has not been studied. Here we show that oncogenic miR-182 is a strong regulator of C/EBPα. Moreover, we identify a regulatory loop between C/EBPα and miR-182. While C/EBPα blocks miR-182 expression by direct promoter binding during myeloid differentiation, enforced expression of miR-182 reduces C/EBPα protein level and impairs granulopoiesis in vitro and in vivo. In addition, miR-182 expression is highly elevated particularly in acute myeloid leukemia patients with C-terminal CEBPA mutations, thereby depicting a mechanism by which C/EBPα blocks miR-182 expression. Furthermore, we present miR-182 expression as a prognostic marker in cytogenetically high-risk acute myeloid leukemia patients. Our data demonstrate the importance of a controlled balance between C/EBPα and miR-182 for the maintenance of healthy granulopoiesis.C/EBPα is a critical transcription factor involved in myelopoiesis and its inactivation is associated with acute myeloid leukemia (AML). Here the authors show a negative feedback loop between C/EBPα and miR-182 and identify this miRNA as a marker of high-risk AML.

• MeSH
• akutní myeloidní leukemie genetika   metabolismus   mortalita   MeSH
• buněčná diferenciace genetika   MeSH
• granulocyty * MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• leukopoéza genetika   MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• myši knockoutované MeSH
• myši MeSH
• prognóza MeSH
• proteiny vázající zesilovač transkripce CCAAT genetika   metabolismus   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• CEBPA protein, human MeSH Prohlížeč
• CEBPA protein, mouse MeSH Prohlížeč
• mikro RNA MeSH
• Mirn182 microRNA, human MeSH Prohlížeč
• Mirn182 microRNA, mouse MeSH Prohlížeč
• proteiny vázající zesilovač transkripce CCAAT MeSH

Cancer development is a dynamic process during which the successive accumulation of mutations results in cells with increasingly malignant characteristics. Here, we show the clonal evolution pattern in myelodysplastic syndrome (MDS) patients receiving supportive care, with or without lenalidomide (follow-up 2.5-11 years). Whole-exome and targeted deep sequencing at multiple time points during the disease course reveals that both linear and branched evolutionary patterns occur with and without disease-modifying treatment. The application of disease-modifying therapy may create an evolutionary bottleneck after which more complex MDS, but also unrelated clones of haematopoietic cells, may emerge. In addition, subclones that acquired an additional mutation associated with treatment resistance (TP53) or disease progression (NRAS, KRAS) may be detected months before clinical changes become apparent. Monitoring the genetic landscape during the disease may help to guide treatment decisions.

• MeSH
• buňky kostní dřeně účinky léků   metabolismus   patologie   MeSH
• chemorezistence genetika   MeSH
• GTP-fosfohydrolasy genetika   metabolismus   MeSH
• inhibitory angiogeneze terapeutické užití   MeSH
• klonální evoluce účinky léků   MeSH
• lenalidomid MeSH
• lidé středního věku MeSH
• lidé MeSH
• management nemoci MeSH
• membránové proteiny genetika   metabolismus   MeSH
• monitorování fyziologických funkcí MeSH
• mutace MeSH
• myelodysplastické syndromy farmakoterapie   genetika   metabolismus   patologie   MeSH
• nádorové biomarkery genetika   metabolismus   MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• následné studie MeSH
• progrese nemoci MeSH
• protoonkogenní proteiny p21(ras) genetika   metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• sekvenování exomu MeSH
• senioři MeSH
• thalidomid analogy a deriváty   terapeutické užití   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• GTP-fosfohydrolasy MeSH
• inhibitory angiogeneze MeSH
• KRAS protein, human MeSH Prohlížeč
• lenalidomid MeSH
• membránové proteiny MeSH
• nádorové biomarkery MeSH
• nádorový supresorový protein p53 MeSH
• NRAS protein, human MeSH Prohlížeč
• protoonkogenní proteiny p21(ras) MeSH
• thalidomid MeSH
• TP53 protein, human MeSH Prohlížeč

The DNA methyl-transferase 3A gene (DNMT3A) is the third most frequently mutated gene in cytogenetically normal acute myeloid leukemia (CN-AML) patients (20-30 %), who belong to a group of patients with intermediate risk. About 60 % of mutations in this gene have been identified in the arginine codon R882. To date, there is no consensus on whether these mutations can be used as biomarkers for monitoring of minimal residual disease and management of preemptive AML therapy. We studied the occurrence of mutations in the DNMT3A gene in our cohort of patients and their persistence during AML treatment. Using next-generation sequencing, we identified four mutations in 11/25 of our analyzed patients--frequent R882C and R882H mutations, rare Y735S mutation, and a novel L347P mutation. Mutation R882C was detected in 5/11, R882H in 4/11 patients, and Y735S and L347P in one patient each. In 4/7 patients initially carrying mutations in the R882 codon, we found the persistence of mutations also during complete remission with, however, no correlation to AML kinetics. Our findings suggest that mutations in the DNMT3A gene can only be used as a biomarker for those AML patients in whom DNMT3A mutation is lost after therapy.

• Klíčová slova
• AML preleukemic stem cells, DNMT3A gene mutations, MRD, Next-generation sequencing,
• MeSH
• akutní myeloidní leukemie genetika   MeSH
• DNA methyltransferasa 3A MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• dospělí MeSH
• kodon genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• missense mutace * MeSH
• monitorování fyziologických funkcí * MeSH
• nádorové biomarkery genetika   MeSH
• nádorové proteiny genetika   MeSH
• reziduální nádor MeSH
• senioři MeSH
• substituce aminokyselin MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA methyltransferasa 3A MeSH
• DNA-(cytosin-5-)methyltransferasa MeSH
• DNMT3A protein, human MeSH Prohlížeč
• kodon MeSH
• nádorové biomarkery MeSH
• nádorové proteiny MeSH