|
|
The role of somatic mutations in the pathogenesis of myelodysplastic syndrome
Minařík, Ľubomír ; Stopka, Tomáš (advisor) ; Žák, Pavel (referee) ; Beličková, Monika (referee)
9 Abstract: Myelodysplastic syndromes (MDS) are a set of severe hematological diseases characterized by ineffective clonal hematopoiesis in the bone marrow, leading to cytopenia in the peripheral blood, the development of transfusion dependence and a high risk of progression to acute myeloid leukemia (AML). The disease is caused by genetic and epigenetic changes leading to the development of pathological stem cells that are unable to mature sufficiently in the bone marrow into blood elements. These changes vary widely between patients, which is reflected in different clinical manifestations, response to treatment, overall survival and, last but not least, this heterogeneity represents a challenge for the study of this disease. The present dissertation is aimed at studying the pathophysiological manifestations and consequences of selected genetic alterations, especially somatic mutations of key genes and other functional units of the genome, in relation to the clinical course of MDS and transformation to AML. Therapy of high-risk MDS is currently based on hypomethylating drugs including 5- azacytidine (AZA). Treatment leads to prolongation of disease progression to AML, but this fate is irreversible for the vast majority of patients whose prognosis becomes hopeless at this point. Results of genetic analysis...
|
|
|
Early Detection of Disease Progression in Patients with Myelodysplastic Syndromes.
Kaisrlíková, Monika ; Beličková, Monika (advisor) ; Kalinová, Markéta (referee) ; Zemanová, Zuzana (referee)
Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic disorders with a risk of transformation into acute myeloid leukemia (AML). The International Prognostic Scoring Systems integrate clinical data and cytogenetics to determine the risk of AML transformation for individual patients. Precise risk assessment is crucial for treatment decision- making. The aim of this thesis was to identify molecular markers for the early detection of disease progression in MDS patients. Using cDNA microarrays and next-generation sequencing, we targeted long noncoding RNAs (lncRNAs) and recurrently mutated genes in bone marrow cells. In addition, we focused on the identification of pathways related to the progression of MDS and understanding how the identified biomarkers participate. In the transcriptome study, we identify 4 candidate lncRNAs that may serve as prognostic biomarkers of the adverse course of MDS: H19, WT1-AS, TCL6, and LEF1-AS. Using various statistical approaches, we determined the level of H19 to be a strong independent prognostic marker. Furthermore, our data showed that disruption of transcriptional coregulation of the imprinting locus H19/IGF2 and miR-675, which directly regulates H19 and plays a role in tumorigenesis, accompanies disease progression. In the genomic study...
|
|
|
Myelodysplastic syndromes - search for the molecular basis]
Beličková, Monika
Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders with ineffective hematopoiesis. It is characterized by morphological dysplasia, peripheral cytopenias affecting one or more cell lineages and an increased risk of transformation into acute myeloid leukemia (AML). The early stages of MDS can be considered a premalignant disease. The pathogenesis of MDS has not been fully explained yet, but due to the development of molecular genetic and cytogenetic methods, the origin and development of the disease is gradually being elucidated. In addition to the cytogenetic changes that are part of the prognostic system (IPSS-R), the somatic mutations found in different genes come to the forefront of interest. However, they are not routinely used in clinical practice. One of the objectives of this study was monitoring of mutations in TP53 gene in lower-risk MDS patients who generally have a good prognosis and for whom these findings have a particularly relevant prognostic significance. We investigated a total of 154 patients with lower-risk MDS, and 13% of them had a mutation. After dividing patients according to the presence of del(5q), we observed significant differences in the incidence of the mutations. The mutations were detected in 23.6% of patients with...
|
|
|
Myelodysplastic syndromes - search for the molecular basis]
Beličková, Monika
Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders with ineffective hematopoiesis. It is characterized by morphological dysplasia, peripheral cytopenias affecting one or more cell lineages and an increased risk of transformation into acute myeloid leukemia (AML). The early stages of MDS can be considered a premalignant disease. The pathogenesis of MDS has not been fully explained yet, but due to the development of molecular genetic and cytogenetic methods, the origin and development of the disease is gradually being elucidated. In addition to the cytogenetic changes that are part of the prognostic system (IPSS-R), the somatic mutations found in different genes come to the forefront of interest. However, they are not routinely used in clinical practice. One of the objectives of this study was monitoring of mutations in TP53 gene in lower-risk MDS patients who generally have a good prognosis and for whom these findings have a particularly relevant prognostic significance. We investigated a total of 154 patients with lower-risk MDS, and 13% of them had a mutation. After dividing patients according to the presence of del(5q), we observed significant differences in the incidence of the mutations. The mutations were detected in 23.6% of patients with...
|
|
|
Myelodysplastic syndromes - search for the molecular basis]
Beličková, Monika ; Čermák, Jaroslav (advisor) ; Divoký, Vladimír (referee) ; Pospíšilová, Dagmar (referee)
Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders with ineffective hematopoiesis. It is characterized by morphological dysplasia, peripheral cytopenias affecting one or more cell lineages and an increased risk of transformation into acute myeloid leukemia (AML). The early stages of MDS can be considered a premalignant disease. The pathogenesis of MDS has not been fully explained yet, but due to the development of molecular genetic and cytogenetic methods, the origin and development of the disease is gradually being elucidated. In addition to the cytogenetic changes that are part of the prognostic system (IPSS-R), the somatic mutations found in different genes come to the forefront of interest. However, they are not routinely used in clinical practice. One of the objectives of this study was monitoring of mutations in TP53 gene in lower-risk MDS patients who generally have a good prognosis and for whom these findings have a particularly relevant prognostic significance. We investigated a total of 154 patients with lower-risk MDS, and 13% of them had a mutation. After dividing patients according to the presence of del(5q), we observed significant differences in the incidence of the mutations. The mutations were detected in 23.6% of patients with...
|
|
| |
|
| |
|
|
The expression of TP53 gene at the mRNA level in patients with myelodysplastic syndrome
Šeborová, Karolína ; Beličková, Monika (advisor) ; Španielová, Hana (referee)
Myelodysplastic syndrome (MDS) is a heterogeneous group of diseases characterized by ineffective hematopoiesis which is caused by damage of differentiation of pluripotent haematopoietic stem cells. TP53 gene mutations are identified approximately in 10% of MDS and represent a negative prognostic factor. Altered TP53 gene expression may have similar effect as the mutation. Mutations or deregulated expression of this gene have an impact on many cellular processes including apoptosis, DNA repair, cell growth and angiogenesis. In this work, the expression mRNA levels of genes involved in p53 signalling pathway were studied in CD34+ pluripotent haematopoietic cells from bone marrow of patients with low- risk MDS. MDS patients showed increased expression of genes involved in apoptosis induction, regulation of cell cycle and DNA repair (BAX, BBC3, CCNE1, CDC25A, CDKN1A, FAS, GADD45A) as compared to healthy subjects. The patients with TP53 mutation had decreased expression of apoptotic genes (BAX, PIDD, TRAF2) and increased gene expression of apoptotic inhibitor (BCL2A1), indicating a reduced activity of apoptotic pathways and that way the pathological cell clone may gain a growth advantage. Deregulation of 21 genes (BAX, BBC3, EGR1, KAT2B, MDM2 etc.) was observed in patients with del (5q) compared to...
|
|
|
DNA methylation in haematological malignancies
Šeborová, Karolína ; Beličková, Monika (advisor) ; Vopálenský, Václav (referee)
DNA methylation is one of the most common epigenetics modifications, during which a methyl group from the donor molecule S-adenosyl-L-methionine is transferred to the 5'position of the cytosine ring to create 5-methylcytosine. This reaction is catalyzed by DNA methyltransferases. Epigenetics modification plays an important role in the regulation of the transcription, genomic imprinting, X-chromosome inactivation and the development of the organism. This role in the regulation of transcription is important for the cancer. Especially the aberrant forms, like hypermethylation, which leads to transcriptional silencing of the tumor suppressing genes leading to the tumor progression, or hypomethylation causing genomic instability. Key words: DNA methylation, demethylating drugs, haematological malignancies, methods of detection, myelodysplastic syndrome
|
|
|
Profiling of extracellular microRNA in acute myeloid leukemia before and after treatment
Štěrbová, Monika ; Korabečná, Marie (advisor) ; Beličková, Monika (referee)
Acute myeloid leukemia (AML) the most common acute leukemia in adults is characterized by various cytogenetic and molecular abnormalities. However, the genetic etiology of the disease is not yet fully understood. MicroRNAs (miRNAs) are small single- stranded noncoding RNAs that are negative regulators of gene expression. miRNAs influence processes of proliferation, differentiation and apoptosis. Deregulation of miRNAs expression can contribute to human disease. Circulating miRNAs are emerging biomarkers in many diseases and cancers such as breast cancer, colorectal cancer and lung cancer. However, defining a plasma miRNA signature in AML that could serve as a biomarker for diagnosis has been conducted only once. We studied miRNA expression in plasma of 8 AML patients in first detection of the disease and repeatedly after achieving remission using TaqMan miRNA microarray for 750 human miRNA. The plasma expression level of 25 miRNA was down-regulated whilst that of 20 miRNA was up-regulated in the AML group at diagnosis when compared to healthy controls. The plasma expression level of 21 miRNA was down-regulated whilst that of 13 miRNA was up-regulated in the AML group in remission compared to healthy controls. Keywords acute myeloid leukemia (AML), biomarker, microRNA (miRNA), plasma, TaqMan Low...
|
guest ::
RSS feed.