AIMS: The aim of this study was to compare the expression profile of selected DNA methyltransferases and global DNA methylation status in patients with different phases of multiple myeloma (MM) . For the analysis, different cellular populations including unsorted myeloma cells and a set of plasma cells purified by relevant antibodies were used. Consequently, laboratory data were compared to patients' clinical data. PATIENTS AND METHODS: For the analysis, unsorted bone marrow cell population of 44 MM patients (30 newly diagnosed, 9 relapsed and 5 patients in remission) and a set of 8 patients' samples of sorted plasma cells were used. We used commercially available RNA isolated from BM of 3 healthy individuals as control samples. Expression analysis of three DNA methyltransferases - DNMT1, DNMT3A, and DNMT3B was performed by quantitative RT-PCR and the patient global DNA methylation profiles were detected by colorimetric assay. RESULTS: Unchanged DNMT1 expression was detected in the selected cohort of patients. Normalized DNMT3A gene expression was globally higher in comparison with controls in unsorted and sorted cell populations. Low (0.08-1.81%) global DNA methylation status in unsorted samples of multiple myeloma patients did not correlate either with expression profiles of monitored DNA methyltransferases or with the stages of MM based on Durie-Salmon and International Staging System. CONCLUSION: This is the first comparative study between DNA methyltransferases expression profiles and global DNA methylation status in different phases of multiple myeloma patients. No significant correlation between the level of global methylation and the clinical stage of the unsorted cell population of patients with multiple myeloma was registered. Overexpression of the DNMT3A gene occurred in both sorted and unsorted cell populations of patients with multiple myeloma. This fact highlights the DNMT3A as a potential marker of multiple myeloma tumor progression. Moreover, we demonstrated comparable results in the expression of DNA methyltransferases in both sorted and unsorted cell populations. This is a promising result from the methodical point of view because when compared to samples of unsorted multiple myeloma cells, samples of sorted cells bring reduction of the number of possible analyses performed.

• MeSH
• DNA methyltransferasa 3A MeSH
• DNA MeSH
• lidé MeSH
• metylace DNA * MeSH
• mnohočetný myelom * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The immune system is important for elimination of residual leukemic cells during acute myeloid leukemia (AML) therapy. Anti-leukemia immune response can be inhibited by various mechanisms leading to immune evasion and disease relapse. Selected markers of immune escape were analyzed on AML cells from leukapheresis at diagnosis (N = 53). Hierarchical clustering of AML immunophenotypes yielded distinct genetic clusters. In the absence of DNMT3A mutation, NPM1 mutation was associated with decreased HLA expression and low levels of other markers (CLIP, PD-L1, TIM-3). Analysis of an independent cohort confirmed decreased levels of HLA transcripts in patients with NPM1 mutation. Samples with combined NPM1 and DNMT3A mutations had high CLIP surface amount suggesting reduced antigen presentation. TIM-3 transcript correlated not only with TIM-3 surface protein but also with CLIP and PD-L1. In our cohort, high levels of TIM-3/PD-L1/CLIP were associated with lower survival. Our results suggest that AML genotype is related to blast immunophenotype, and that high TIM-3 transcript levels in AML blasts could be a marker of immune escape. Cellular pathways regulating resistance to the immune system might contribute to the predicted response to standard therapy of patients in specific AML subgroups and should be targeted to improve AML treatment.

• MeSH
• akutní myeloidní leukemie * diagnóza   genetika   MeSH
• antigeny CD274 genetika   MeSH
• biologické markery MeSH
• buněčný receptor 2 viru hepatitidy A genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• lidé MeSH
• mutace MeSH
• nukleofosmin * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

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

OBJECTIVES: Recently, mutations in DNMT3A gene have been described in about 25% acute myeloid leukemia (AML) cases, preferentially in monocytic AML. They were found to predict worse overall survival (OS) of mutated patients. PATIENTS AND METHODS: RT-PCR followed by direct sequencing was used to test the presence of DNMT3A mutations in 226 AML patients with an intermediate-risk (IR) cytogenetics. RESULTS: Sixty-seven patients of 226 (29.6%) carried a mutation in the DNMT3A gene. Occurrence of DNMT3A mutations was associated with female sex (P = 0.027) and with the presence of FLT3/ITD (P = 0.003), but not with particular FAB subtypes. Patients with DNMT3A mutation had higher initial WBC counts than those without it (P = 0.064) only because of higher incidence of FLT3/ITD within these cases. There was no difference between mutated and wild-type groups in reaching complete remission (CR) (P = 0.380). OS was not affected by DNMT3A mutation (P = 0.251), but OS of patients who reached CR was longer in DNMT3A negative cases (P = 0.025). Patients with DNMT3A mutation had a higher relapse rate (P = 0.007). Patients carrying both the DNMT3A mutation and FLT3/ITD relapsed more often than either patients with single DNMT3A mutation (P = 0.044) or patients with FLT3/ITD only (P = 0.058). DNMT3A mutations were associated with higher relapse rate even within the FLT3/ITD-negative group (P = 0.072). After reaching CR, these two genetic factors were independent predictors of relapse at multivariate analysis (P < 0.001). Only three of 30 'double-mutated' (FLT3/ITD+, DNMT3A+) patients are still alive, all of them having undergone hematopoietic stem cell transplant. CONCLUSIONS: We have confirmed the high incidence of DNMT3A mutations in patients with AML with IR cytogenetics. Patients with DNMT3A mutations relapse more often and have inferior OS when only patients achieving CR are analyzed. 'Double-mutated' patients have a very poor prognosis.

• MeSH
• akutní myeloidní leukemie genetika   mortalita   MeSH
• chromozomální aberace MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• dospělí MeSH
• incidence MeSH
• indukce remise MeSH
• Kaplanův-Meierův odhad MeSH
• kodon MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace MeSH
• prognóza MeSH
• recidiva MeSH
• rizikové faktory MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• tyrosinkinasa 3 podobná fms metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• akutní myeloidní leukemie genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• lidé MeSH
• mutace genetika   MeSH
• nádorové biomarkery genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• komentáře MeSH
• úvodníky MeSH

We examined 79 acute myeloid leukemia (AML) patients for DNA methylation of 12 tumor suppressor genes (TSG) and 24 homeobox domain (Hox) genes, and additionally for mutations in DNMT3A gene. We observed lower levels of DNA methylation (P<0.0001) as well as smaller numbers of concurrently hypermethylated genes (P<0.0001) in patients with DNMT3A mutations. Our study of the impact of DNA methylation on prognosis in intermediate and high risk AML patients revealed a relation between higher DNA methylation and better patients' outcome. Lower DNA methylation was linked with higher relapse rates and an inferior overall survival.

• MeSH
• akutní myeloidní leukemie diagnóza   genetika   mortalita   MeSH
• analýza přežití MeSH
• cytogenetické vyšetření MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• dospělí MeSH
• down regulace genetika   MeSH
• epigeneze genetická fyziologie   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• metylace DNA genetika   MeSH
• missense mutace fyziologie   MeSH
• mladý dospělý MeSH
• prognóza MeSH
• regulace genové exprese u leukemie genetika   fyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Aberrant epigenetic patterns are a hallmark of acute myeloid leukemia (AML). Mutations in profound epigenetic regulators DNMT3A and IDH1/2 often occur concurrently in AML. OBJECTIVES: The aim was to analyze DNA methylation, hydroxymethylation and mRNA expression profiles in AML with mutations in DNMT3A and IDH1/2 (individually and in combinations). METHODS: Infinium MethylationEPIC BeadChip (Illumina) covering 850,000 CpGs was utilized. The validation of hydroxy-/methylation data was done by pyrosequencing. HumanHT-12 v4 Expression BeadChip (Illumina) was used for expression examination. RESULTS: Hierarchical clustering analysis of DNA hydroxy-/methylation data revealed clusters corresponding to DNMT3A and IDH1/2 mutations and CD34+ healthy controls. Samples with concurrent presence of DNMT3A and IDH1/2 mutations displayed mixed DNA hydroxy-/methylation profile with preferential clustering to healthy controls. Numbers and levels of DNA hydroxymethylation were low. Uniformly hypermethylated loci in AML patients with IDH1/2 mutations were enriched for immune response and apoptosis related genes, among which hypermethylation of granzyme B (GZMB) was found to be associated with inferior overall survival of AML patients (P= 0.035). CONCLUSIONS: Distinct molecular background results in specific DNA hydroxy-/methylation profiles in AML. Site-specific DNA hydroxymethylation changes are much less frequent in AML pathogenesis compared to DNA methylation. Methylation levels of enhancer located upstream GZMB gene might contribute to AML prognostication models.

• MeSH
• akutní myeloidní leukemie genetika   metabolismus   MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• granzymy genetika   MeSH
• isocitrátdehydrogenasa genetika   MeSH
• leukocyty mononukleární metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metylace DNA * MeSH
• mutace MeSH
• prognóza MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stanovení celkové genové exprese MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• akutní myeloidní leukemie genetika   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

Správné řízení genové exprese hraje zásadní roli v diferenciaci hematopoetických kmenových buněk a dalších procesech hematopoézy. Zásah do epigenetické regulace genové exprese charakterizuje patogenezi celé řady nejen hematologických malignit. V genomech pacientů s akutní myeloidní leukemií, zejména ve skupině s normálním karyotypem, byly opakovaně prokázány somatické mutace v epigenetických regulátorech vč. DNMT3A, TET2, IDH1, IDH2, ASXL1, MLL nebo EZH2. Jedná se o časné preleukemické zásahy, které bývají stabilním ukazatelem klinického vývoje onemocnění a v kombinaci s „driver“ mutacemi (NPM1, FLT3, MLL, RUNX1 aj.) představují kandidátní markery pro monitorování minimální reziduální nemoci. Specifický mutační profil každého pacienta získaný s využitím moderních molekulárních metod, jako je sekvenování nové generace, může přinést zásadní informaci o případném rozvoji relapsu či dosažení remise onemocnění. Cílem této práce je shrnout poznatky o klinickém, biologickém a terapeutickém významu mutací vybraných epigenetických regulátorů rekurentních u akutní myeloidní leukemie.

Regulation of gene expression, especially in hematopoietic stem cells, plays an essential role in differentiation and other important processes of haematopoiesis. Pathogenesis of different malignant diseases is characterised by disruption of epigenetic regulation. Certain somatic mutations, including genes such as DNMT3A, TET2, IDH1, IDH2, ASXL1, MLL or EZH2, have been found in acute myeloid leukaemia, especially in patients with normal karyotype AML. These mutations are considered to be pre-leukemic events and are stable indicators of clinical course. In combination with driver mutations, they are suitable markers for monitoring minimal residual disease. Specific mutational profiles of individual patients could provide essential information about disease progression, relapse or achievement of complete remission. The aim of this article is to review current knowledge regarding the clinical and therapeutical value of mutations in selected genes involved in epigenetic regulation of gene expression in acute myeloid leukaemia.

• MeSH
• akutní myeloidní leukemie * diagnóza   farmakoterapie   genetika   MeSH
• antitumorózní látky farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie MeSH
• epigeneze genetická * genetika   MeSH
• lidé MeSH
• metylace DNA MeSH
• mutace genetika   MeSH
• prognóza MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Somatické mutace protoonkogenů RAS(rat sarcoma viral oncogene homolog) vedou k nekontrolované konstitutivní aktivaci RAS indukovaných signálních drah ovlivňujících procesy proliferace, diferenciace a apoptózy buněk. U pacientů s akutní myeloidní leukemií (AML) lze mutace genů RAS identifikovat u přibližně pětiny nemocných. Mutace jsou heterozygotní, typu "missense“, lokalizované především do kodonů G12, G13 a Q61 exonů 2 a 3. Nejčastěji mutovaným genem rodiny je NRAS. Vzácně lze identifikovat případy pacientů se současným výskytem mutací v genu NRAS i genu KRAS. Přibližně desetina NRAS pozitivních AML pacientů vykazuje polyklonalitu mutací. Mutace genů RAS jsou často detekovány společně s chromozomálními aberacemi inv(16)/t(16;16) či t(8;21), ale také inv(3)/t(3;3) nebo s normálním karyotypem a mutacemi v genech NPM1 a DNMT3A. Většina velkých publikovaných studií nepotvrdila vliv mutací na celkové přežití pacientů. Asociace mutací s dalšími klinickými parametry je nejednoznačná. V procesu leukemogeneze jsou mutace genů rodiny RAS sekundární událostí přispívající k progresi a proliferaci AML subklonů. Cílem předkládané práce je shrnutí aktuálních poznatků o genové rodině RAS a jejím významu u pacientů s AML.

Somatic mutations in RAS (rat sarcoma viral oncogene homolog) proto-oncogenes lead to constitutive activation of RAS signalling pathways impacting cellular proliferation, differentiation and apoptosis. RAS mutations are detected in approximately one fifth of patients with acute myeloid leukaemia (AML). Typically, the aberrations are missense heterozygous point mutations localized in codons G12, G13 and Q61 in exons 2 and 3, respectively. In AML, NRAS is the most frequently mutated gene of the RAS family. Simultaneously mutated NRAS and KRAS genes in one patient are possible, but rare. In approximately 10% of AML patients, multiple NRAS mutations are detected. The RAS mutations occur with higher frequency in AML patients with chromosomal aberrations inv(16)/t(16;16), t(8;21), inv(3)/t(3;3). In patients with normal karyotype, the RAS genes are frequently co-mutated with the NPM1 and DNMT3A genes. Most of the large cohort studies did not demonstrate any implication of RAS mutations on overall survival, and its occurrence was not significantly associated with any clinical parameters. During leukaemogenesis, RAS mutations play a role as late secondary events supporting increased proliferation of AML subclones. The aim of this work is to summarize the current knowledge about the RAS gene family and its significance in patients with AML.

• MeSH
• akutní myeloidní leukemie * genetika   MeSH
• geny ras MeSH
• lidé MeSH
• mutace genetika   MeSH
• Check Tag
• lidé MeSH