Patients with myelodysplastic neoplasms (MDS) are classified according to the risk of acute myeloid leukemia transformation. Some lower-risk MDS patients (LR-MDS) progress rapidly despite expected good prognosis. Using diagnostic samples, we aimed to uncover the mechanisms of this accelerated progression at the transcriptome level. RNAseq was performed on CD34+ ribodepleted RNA samples from 53 LR-MDS patients without accelerated progression (stMDS) and 8 who progressed within 20 months (prMDS); 845 genes were differentially expressed (ІlogFCІ > 1, FDR < 0.01) between these groups. stMDS CD34+ cells exhibited transcriptional signatures of actively cycling, megakaryocyte/erythrocyte lineage-primed progenitors, with upregulation of cell cycle checkpoints and stress pathways, which presumably form a tumor-suppressing barrier. Conversely, cell cycle, DNA damage response (DDR) and energy metabolism-related pathways were downregulated in prMDS samples, whereas cell adhesion processes were upregulated. Also, prMDS samples showed high levels of aberrant splicing and global lncRNA expression that may contribute to the attenuation of DDR pathways. We observed overexpression of multiple oncogenes and diminished differentiation in prMDS; the expression of ZEB1 and NEK3, genes not previously associated with MDS prognosis, might serve as potential biomarkers for LR-MDS progression. Our 19-gene DDR signature showed a significant predictive power for LR-MDS progression. In validation samples (stMDS = 3, prMDS = 4), the key markers and signatures retained their significance. Collectively, accelerated progression of LR-MDS appears to be associated with transcriptome patterns of a quiescent-like cell state, reduced lineage differentiation and suppressed DDR, inherent to CD34+ cells. The attenuation of DDR-related gene-expression signature may refine risk assessment in LR-MDS patients.
- MeSH
- buněčná adheze MeSH
- buněčný cyklus MeSH
- kinasy NEK genetika metabolismus MeSH
- lidé MeSH
- myelodysplastické syndromy * genetika MeSH
- nádory * MeSH
- oprava DNA MeSH
- transkriptom MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: To date, no chemoresistance predictors are included in acute myeloid leukaemia (AML) prognostic scoring systems to distinguish responding and refractory AML patients prior to chemotherapy. ABC transporters have been described as altering AML chemosensitivity; however, a relevant study investigating their role at various molecular levels was lacking. METHODS: Gene expression, genetic variants, methylation and activity of ABCA2, ABCA5, ABCB1, ABCB6, ABCC1, ABCC3 and ABCG2 were analysed in AML blasts and healthy myeloblasts. Differences between responding and refractory AML in a cohort of 113 patients treated with 3 + 7 induction therapy were explored. RESULTS: ABCC3 variant rs2301837 (p = 0.049), ABCG2 variant rs11736552 (p = 0.044), higher ABCA2 (p = 0.021), ABCC1 (p = 0.017), and ABCG2 expression (p = 0.023) and a higher number of concurrently overexpressed transporters (p = 0.002) were predictive of treatment failure by multivariate analysis. Expression of ABCA5 (p = 0.003), ABCB6 (p = 0.001) and ABCC3 (p < 0.0001) increased significantly after chemotherapy. Higher ABCG2 promoter methylation correlated with lower ABCG2 expression (p = 0.0001). ABCC1 was identified as the most active transporter in AML blasts by functional analysis. CONCLUSIONS: ABC transporters, especially ABCC1 seem to contribute substantially to AML chemoresistance. A detailed understanding of chemoresistance mechanisms and the clinical implications of chemosensitivity predictors may lead to alternative therapeutic approaches for AML patients with unveiled chemoresistance signatures.
- MeSH
- ABC transportéry * metabolismus MeSH
- akutní myeloidní leukemie * farmakoterapie genetika MeSH
- chemorezistence genetika MeSH
- lidé MeSH
- terapie neúspěšná MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Mutations in the splicing factor 3b subunit 1 (SF3B1) gene are frequent in myelodysplastic neoplasms (MDS). Because the splicing process is involved in the production of circular RNAs (circRNAs), we investigated the impact of SF3B1 mutations on circRNA processing. Using RNA sequencing, we measured circRNA expression in CD34+ bone marrow MDS cells. We defined circRNAs deregulated in a heterogeneous group of MDS patients and described increased circRNA formation in higher-risk MDS. We showed that the presence of SF3B1 mutations did not affect the global production of circRNAs; however, deregulation of specific circRNAs was observed. Particularly, we demonstrated that strong upregulation of circRNAs processed from the zinc finger E-box binding homeobox 1 (ZEB1) transcription factor; this upregulation was exclusive to SF3B1-mutated patients and was not observed in those with mutations in other splicing factors or other recurrently mutated genes, or with other clinical variables. Furthermore, we focused on the most upregulated ZEB1-circRNA, hsa_circ_0000228, and, by its knockdown, we demonstrated that its expression is related to mitochondrial activity. Using microRNA analyses, we proposed miR-1248 as a direct target of hsa_circ_0000228. To conclude, we demonstrated that mutated SF3B1 leads to deregulation of ZEB1-circRNAs, potentially contributing to the defects in mitochondrial metabolism observed in SF3B1-mutated MDS.
Východiska: Hypoplastická forma myelodysplastické neoplazie (MDS-h) je vzácná porucha krvetvorby charakterizována periferní cytopenií, hypoplazií (celularita ≤ 25 %) a dysplastickými změnami v kostní dřeni. Ve srovnání s normo-/hypercelulárním MDS je kromě hypocelularity u pacientů s MDS-h nalézána těžší neutropenie a trombocytopenie, nižší procento blastů a méně častěji abnormální karyotyp. Při diferenciální diagnóze je obtížné odlišit především MDS-h od aplastické anemie. Abnormální karyotyp je nalézán u 15–50 % pacientů s MDS-h a mezi nejběžnější chromozomální aberace patří −5/del (5q), −7/del (7q), +8, 17pLOH, del (20q), UPD v 4q, 11q, 13q, 14q. Přibližně 35 % pacientů s MDS-h nese somatické mutace, které jsou nejčastěji detekovány v genech PIGA, TET2, DNMT3A, RUNX1, NPM1, ASXL1, STAG2, APC. V patofyziologii MDS-h hraje klíčovou roli defektní imunitní odpověď, při které dochází k poškození hematopoetických kmenových buněk (hematopoietic stem cells – HSC) nebo progenitorových buněk (hematopoietic progenitor cells – HPC) abnormálně aktivovanými T buňkami. Expandované T buňky produkují nadměrné množství prozánětlivých cytokinů (IFN- g a TNF-a), které inhibují proliferaci HSC/HPC a indukují jejich apoptózu. Antigeny spouštějící abnormální imunitní odpověď nejsou známy, ale mezi potenciální kandidáty patří protein WT1 a molekuly HLA I. třídy. MDS-h nepředstavuje fenotypově homogenní podskupinu MDS, ale spíše jde o smíšenou entitu zahrnující jak pacienty vykazující znaky podobné myeloidní neoplazii, tak pacienty se znaky nemaligního útlumu kostní dřeně. Právě stanovení převažujícího fenotypu u MDS-h je důležité pro zvolení optimální léčby a predikci prognózy. Cíl: Cílem tohoto sdělení je poukázat na zajímavou hypoplastickou formu MDS, jejíž diagnostika je obtížná, a přehledně popsat její hlavní klinicko-patologické znaky, genetické pozadí a mechanizmy abnormální imunitní odpovědi.
Background: Hypoplastic myelodysplastic neoplasm (MDS-h) is a rare hematopoietic disorder characterized by peripheral cytopenia, hypoplasia (cellularity ≤ 25%) and dysplastic changes in the bone marrow. Compared to normo- /hypercellular MDS, in addition to hypocellularity, MDS-h patients have more profound neutropenia and thrombocytopenia, a lower percentage of blasts, and less frequent abnormal karyotype. It is difficult to distinguish MDS-h from aplastic anemia in differential diagnosis. Abnormal karyotype is found in 15–50% of MDS-h patients and the most common chromosomal aberrations include −5/del (5q), −7/del (7q), +8, 17pLOH, del (20q), UPD at 4q, 11q, 13q, and 14q. Approximately 35% of MDS-h patients harbour somatic mutations that are most often detected in PIGA, TET2, DNMT3A, RUNX1, NPM1, ASXL1, STAG2, and APC genes. An autoimmune destruction of hematopoietic stem cells (HSCs) or hematopoietic progenitor cells (HPCs) mediated by abnormally activated T cells plays a key role in the pathophysiology of MDS-h. Expanded T cells overproduce proinflammatory cytokines (IFN- g and TNF-a), which inhibit proliferation and induce apoptosis of HSC/HPCs. The antigens that trigger the immune response are not known, but potential candidates have been suggested such as WT1 protein and HLA class I molecules. MDS-h does not represent a phenotypically homogeneous subtype of MDS, but rather it is a mixed entity comprising both patients showing features similar to myelodysplastic neoplasm and patients with features of non-malignant bone marrow failure. Determining the prevailing phenotype in MDS-h is important for choosing the optimal treatment and prognosis prediction. Purpose: The aim of this article is to point out an interesting hypoplastic MDS, the diagnosis of which is difficult, and to provide an overview of its main clinical-pathological features, genetic background, and mechanisms of aberrant immune response.
- MeSH
- aplastická anemie * genetika patofyziologie MeSH
- lidé MeSH
- myelodysplastické syndromy * genetika patofyziologie MeSH
- syndromy selhání kostní dřeně MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
OBJECTIVE: Somatic mutations in UBA1 have recently been causally linked to a severe adult-onset inflammatory condition referred to as VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. Ubiquitin-activating enzyme E1 (UBA-1) is of fundamental importance to the modulation of ubiquitin homeostasis and to the majority of downstream ubiquitylation-dependent cellular processes. Direct sequencing analysis of exon 3 containing the prevalent variants p.Met41Leu, p.Met41Val, and/or p.Met41Thr is usually used to confirm the disease-associated mutations. METHODS: We studied the clinical, biochemical, and molecular genetic characteristics of a 59-year-old man with a 2-year history of arthritis, fever, night sweats, nonspecific skin rash, lymphadenopathy, and myelodysplastic syndrome with multilineage dysplasia. RESULTS: The mutational analysis revealed a previously undescribed sequence variant c.1430G>C in exon 14 (p.Gly477Ala) in the gene UBA1. In vitro enzymatic analyses showed that p.Gly477Ala led to both decreased E1 ubiquitin thioester formation and E2 enzyme charging. CONCLUSION: We report a case of a patient of European ancestry with clinical manifestations of VEXAS syndrome associated with a newly identified dysfunctional UBA-1 enzyme variant. Due to the patient's insufficient response to various immunosuppressive treatments, allogeneic hematopoietic stem cell transplantation was performed, which resulted in significant improvement of clinical and laboratory manifestations of the disease.
- MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mutace MeSH
- myelodysplastické syndromy * MeSH
- pacienti MeSH
- ubikvitin aktivující enzymy * genetika MeSH
- ubikvitiny MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Hypoplastic myelodysplastic syndrome (hMDS) and aplastic anemia (AA) are rare hematopoietic disorders characterized by pancytopenia with hypoplastic bone marrow (BM). hMDS and idiopathic AA share overlapping clinicopathological features, making a diagnosis very difficult. The differential diagnosis is mainly based on the presence of dysgranulopoiesis, dysmegakaryocytopoiesis, an increased percentage of blasts, and abnormal karyotype, all favouring the diagnosis of hMDS. An accurate diagnosis has important clinical implications, as the prognosis and treatment can be quite different for these diseases. Patients with hMDS have a greater risk of neoplastic progression, a shorter survival time and a lower response to immunosuppressive therapy compared with patients with AA. There is compelling evidence that these distinct clinical entities share a common pathophysiology based on the damage of hematopoietic stem and progenitor cells (HSPCs) by cytotoxic T cells. Expanded T cells overproduce proinflammatory cytokines (interferon‐γ and tumor necrosis factor‐α), resulting in decreased proliferation and increased apoptosis of HSPCs. The antigens that trigger this abnormal immune response are not known, but potential candidates have been suggested, including Wilms tumor protein 1 and human leukocyte antigen class I molecules. Our understanding of the molecular pathogenesis of these BM failure syndromes has been improved by next‐generation sequencing, which has enabled the identification of a large spectrum of mutations. It has also brought new challenges, such as the interpretation of variants of uncertain significance and clonal hematopoiesis of indeterminate potential. The present review discusses the main clinicopathological differences between hMDS and acquired AA, focuses on the molecular background and highlights the importance of molecular testing.
- MeSH
- autoimunitní hemolytická anemie etiologie genetika MeSH
- imunita genetika imunologie MeSH
- lidé MeSH
- myelodysplasticko-myeloproliferativní nemoci etiologie genetika MeSH
- prognóza MeSH
- syndromy selhání kostní dřeně etiologie genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Patients with lower-risk myelodysplastic syndromes (LR-MDS) have a generally favorable prognosis; however, a small proportion of cases progress rapidly. This study aimed to define molecular biomarkers predictive of LR-MDS progression and to uncover cellular pathways contributing to malignant transformation. The mutational landscape was analyzed in 214 LR-MDS patients, and at least one mutation was detected in 137 patients (64%). Mutated RUNX1 was identified as the main molecular predictor of rapid progression by statistics and machine learning. To study the effect of mutated RUNX1 on pathway regulation, the expression profiles of CD34 + cells from LR-MDS patients with RUNX1 mutations were compared to those from patients without RUNX1 mutations. The data suggest that RUNX1-unmutated LR-MDS cells are protected by DNA damage response (DDR) mechanisms and cellular senescence as an antitumor cellular barrier, while RUNX1 mutations may be one of the triggers of malignant transformation. Dysregulated DDR and cellular senescence were also observed at the functional level by detecting γH2AX expression and β-galactosidase activity. Notably, the expression profiles of RUNX1-mutated LR-MDS resembled those of higher-risk MDS at diagnosis. This study demonstrates that incorporating molecular data improves LR-MDS risk stratification and that mutated RUNX1 is associated with a suppressed defense against LR-MDS progression.
- MeSH
- akutní myeloidní leukemie * genetika MeSH
- lidé MeSH
- mutace MeSH
- myelodysplastické syndromy * patologie MeSH
- nádorová transformace buněk genetika metabolismus MeSH
- prognóza MeSH
- protein PEBP2A2 genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND/AIM: Prediction of response to azacitidine (AZA) treatment is an important challenge in hematooncology. In addition to protein coding genes (PCGs), AZA efficiency is influenced by various noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular RNAs (circRNAs), and transposable elements (TEs). MATERIALS AND METHODS: RNA sequencing was performed in patients with myelodysplastic syndromes or acute myeloid leukemia before AZA treatment to assess contribution of ncRNAs to AZA mechanisms and propose novel disease prediction biomarkers. RESULTS: Our analyses showed that lncRNAs had the strongest predictive potential. The combined set of the best predictors included 14 lncRNAs, and only four PCGs, one circRNA, and no TEs. Epigenetic regulation and recombinational repair were suggested as crucial for AZA response, and network modeling defined three deregulated lncRNAs (CTC-482H14.5, RP11-419K12.2, and RP11-736I24.4) associated with these processes. CONCLUSION: The expression of various ncRNAs can influence the effect of AZA and new ncRNA-based predictive biomarkers can be defined.
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
Nestr.
Myelodysplastic syndrome is characterized by a high heterogeneity of clinical course and an increased risk of development of acute myeloid leukemia. We assume that so far unexplained mechanism of the disease, leukemia transformation and a large number of mutations detected recently may be related to a decreased function of DNA repair systems, which under physiological conditions form an effective protective barrier against malignant transformation of cells. The project will monitor changes in 84 genes involved in DNA repair mechanisms at the level of genome, transcriptome and proteome, and reparative cell activity using in vitro assays. Due to clonal character of the disease, the changes will be observed mainly in pluripotent hematopoietic CD34+ bone marrow cells. Data obtained using modern molecular genetic techniques such as targeted next generation sequencing will be closely correlated with clinical data of the patients.The proposed project aims to identify new molecular biomarkers involved in the formation and progression of the disease and found new potential therapeutic targ...
Myelodysplastický syndrom (MDS) se vyznačuje vysokou heterogenitou klinického průběhu a sklonem k rozvoji akutní myeloidní leukémie. Nabízí se, že za dosud neobjasněným mechanismem vzniku nemoci, leukemickou transformací a velkým počtem mutací detekovaný v nedávné době by mohla být snížená funkce DNA reparačních systémů, které za fyziologických podmínek tvoří účinnou protektivní bariéru proti malignizaci buněk. V rámci projektu chceme sledovat změny na úrovni genomu, transkriptomu a proteomu v 84 genech zapojených do mechanismů reparace DNA a detekovat reparační aktivitu buněk pomocí in vitro testů. Vzhledem k tomu, že onemocnění má klonální charakter, budou změny sledovány hlavně na úrovni CD34+ pluripotentních hematopoetických buněk kostní dřeně. Data získána pomocí moderních technik molekulární genetiky jako např. cíleného sekvenování nové generace budou podrobně korelována s klinickými daty pacientů. Navrhovaný projekt si klade za cíl identifikovat nové molekulární biomarkery podílející se na vzniku a progresi onemocnění a nalézt nové potencionální terapeutické cíle.
- MeSH
- azacytidin terapeutické užití MeSH
- biologické markery MeSH
- genom lidský genetika MeSH
- lidé MeSH
- myelodysplastické syndromy farmakoterapie genetika MeSH
- nádorová transformace buněk genetika MeSH
- oprava DNA genetika MeSH
- prognóza MeSH
- transformace genetická MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- Check Tag
- lidé MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- genetika, lékařská genetika
- angiologie
- onkologie
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
