Project description:Activating mutations in tyrosine kinase (TK) genes (e.g. FLT3 and KIT) are found in more than 30% of patients with de novo acute myeloid leukemia (AML); many groups have speculated that mutations in other TK genes may be present in the remaining 70%. We performed high-throughput re-sequencing of the kinase domains of 26 TK genes (11 receptor TK and 15 cytoplasmic TK) that are expressed in most AML patients, using genomic DNA from the bone marrow (tumor) and matched skin biopsy samples (germline) from 94 patients with de novo AML; sequence variants were validated in an additional 94 AML tumor samples (14.3 million base pairs of sequence were obtained and analyzed). We identified known somatic mutations in FLT3, KIT, and JAK2 TK genes at the expected frequencies, and found four novel somatic mutations, JAK1V623A, JAK1T478S, DDR1A803V and NTRK1S677N, once each in four respective patients out of 188 tested. We also identified novel germline sequence changes encoding amino acid substitutions (i.e. non-synonymous changes) in 14 TK genes, including TYK2, which had the largest number of non-synonymous sequence variants (11 total detected). Additional studies will be required to define the roles that these somatic and germline TK gene variants play in AML pathogenesis. Experiment Overall Design: 188 patient samples analysed
Project description:This data set was used to study FLT3 wild type and mutants in childhood AML samples from the Pediatric Oncology Group Study 9421. Abstract: Fms-like tyrosine kinase 3 (FLT3) mutations are associated with unfavorable outcomes in children with acute myeloid leukemia (AML). We used DNA microarrays to identify gene expression profiles related to FLT3 status and outcome in childhood AML. Among 81 diagnostic specimens, 36 had FLT3 mutations (FLT3-MUs), 24 with internal tandem duplications (ITDs) and 12 with activating loop mutations (ALMs). In addition, 8 of 19 specimens from patients with relapses had FLT3-MUs. Predictive analysis of microarrays (PAM) identified genes that differentiated FLT3-ITD from FLT3-ALM and FLT3 wild-type (FLT3-WT) cases. Among the 42 specimens with FLT3-MUs, PAM identified 128 genes that correlated with clinical outcome. Event-free survival (EFS) in FLT3-MU patients with a favorable signature was 45% versus 5% for those with an unfavorable signature (P = .018). Among FLT3-MU specimens, high expression of the RUNX3 gene and low expression of the ATRX gene were associated with inferior outcome. The ratio of RUNX3 to ATRX expression was used to classify FLT3-MU cases into 3 EFS groups: 70%, 37%, and 0% for low, intermediate, and high ratios, respectively (P < .0001). Thus, gene expression profiling identified AML patients with divergent prognoses within the FLT3-MU group, and the RUNX3 to ATRX expression ratio should be a useful prognostic indicator in these patients. A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Computed
Project description:Approximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of Nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, Fms-like tyrosine kinase (FLT3) mutations and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 with non-major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc- AMLs, regardless of the presence of FLT3 mutations or non-major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor. 78 de novo AMLs, negative for AML-associated chromosomal translocations at the cytogenetic and/or molecular level.
Project description:Acute myeloid leukemia (AML) is a heterogeneous disease and AML with normal karyotype (AML-NK) is categorized as an intermediate-risk group. Over the past years molecular analyses successfully identified biomarkers that will further allow to dissecting clinically meaningful subgroups in this disease. Thus far, somatic mutations were identified which elucidate the disturbance of cellular growth, proliferation, and differentiation processes in hematopoietic progenitor cells. In AML-NK, acquired gene mutations with prognostic relevance were identified for FLT3, CEBPA, and NPM1. FLT3-ITD mutations were associated with short relapse-free and overall survival, while mutations in CEBPA or NPM1 (without concomitant FLT3-ITD) had a more favorable outcome. Here, we present a multicenter study investigating gene expression profiles of 251 cases of de novo AML-NK. In three centers whole-genome microarray analyses were performed to delineate robust and common expression signatures for molecular markers in AML-NK. All samples were obtained from untreated patients at the time of diagnosis. Cells used for microarray analysis were collected from the purified fraction of mononuclear cells after Ficoll density centrifugation (Dresden, n=78; Munich, n=97; Ulm, n=77). Each laboratory performed its routine diagnostic algorithms, including the characterization of molecular markers.
Project description:Activating mutations in tyrosine kinase (TK) genes (e.g. FLT3 and KIT) are found in more than 30% of patients with de novo acute myeloid leukemia (AML); many groups have speculated that mutations in other TK genes may be present in the remaining 70%. We performed high-throughput re-sequencing of the kinase domains of 26 TK genes (11 receptor TK and 15 cytoplasmic TK) that are expressed in most AML patients, using genomic DNA from the bone marrow (tumor) and matched skin biopsy samples (germline) from 94 patients with de novo AML; sequence variants were validated in an additional 94 AML tumor samples (14.3 million base pairs of sequence were obtained and analyzed). We identified known somatic mutations in FLT3, KIT, and JAK2 TK genes at the expected frequencies, and found four novel somatic mutations, JAK1V623A, JAK1T478S, DDR1A803V and NTRK1S677N, once each in four respective patients out of 188 tested. We also identified novel germline sequence changes encoding amino acid substitutions (i.e. non-synonymous changes) in 14 TK genes, including TYK2, which had the largest number of non-synonymous sequence variants (11 total detected). Additional studies will be required to define the roles that these somatic and germline TK gene variants play in AML pathogenesis. In this ongoing study, we have performed high-throughput sequencing of whole genomes, exomes, and transcriptomes, as well as SNP and expression microarrays, and methylation microarrays, using genomic DNA or RNA from the bone marrow (tumor) and matched skin biopsy samples (germline) from over 300 patients with de novo AML. These samples are also part of the Cancer Genome Atlas (TCGA) study of AML.
Project description:FLT3 activating mutations cause myeloproliferative neoplasms by deregulating hematopoietic progenitor cell growth, and acute myeloid leukemia is on the rise. Investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop inherent and acquired resistance to FLT3 targeted therapy. FLT3 inhibitor resistance in AML is dependent on co-occurring mutations, parallel survival pathways, and/or subsequent FLT3-ITD mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options. We identified two novel naphthyridine-based FLT3 inhibitors (HSN608 and HSN748) that specifically target FLT3-ITD at sub-nanomolar concentrations and are effective against drug-resistant secondary mutations. In the current study, we evaluated these compounds antileukemic activity against FLT3-ITD and gatekeeper mutations in drug-resistant AML, relapsed/refractory AMLs with FLT3 mutations, and in vivo mouse models with combinations of epigenetic mutations TET2 with FLT3-ITD, and AML patients PDX. In these model systems, we demonstrate that HSN748 outperforms the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3-ITD.
Project description:This data set was used to study FLT3 wild type and mutants in childhood AML samples from the Pediatric Oncology Group Study 9421. Abstract: Fms-like tyrosine kinase 3 (FLT3) mutations are associated with unfavorable outcomes in children with acute myeloid leukemia (AML). We used DNA microarrays to identify gene expression profiles related to FLT3 status and outcome in childhood AML. Among 81 diagnostic specimens, 36 had FLT3 mutations (FLT3-MUs), 24 with internal tandem duplications (ITDs) and 12 with activating loop mutations (ALMs). In addition, 8 of 19 specimens from patients with relapses had FLT3-MUs. Predictive analysis of microarrays (PAM) identified genes that differentiated FLT3-ITD from FLT3-ALM and FLT3 wild-type (FLT3-WT) cases. Among the 42 specimens with FLT3-MUs, PAM identified 128 genes that correlated with clinical outcome. Event-free survival (EFS) in FLT3-MU patients with a favorable signature was 45% versus 5% for those with an unfavorable signature (P = .018). Among FLT3-MU specimens, high expression of the RUNX3 gene and low expression of the ATRX gene were associated with inferior outcome. The ratio of RUNX3 to ATRX expression was used to classify FLT3-MU cases into 3 EFS groups: 70%, 37%, and 0% for low, intermediate, and high ratios, respectively (P < .0001). Thus, gene expression profiling identified AML patients with divergent prognoses within the FLT3-MU group, and the RUNX3 to ATRX expression ratio should be a useful prognostic indicator in these patients. A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Keywords: clinical_history_design
Project description:Acute myeloid leukemia (AML) carrying NPM1 mutations and cytoplasmic nucleophosmin (NPMc+ AML) accounts for about one-third of adult AML and shows distinct features, including a unique gene expression profile. MicroRNAs (miRNAs) are small noncoding RNAs of 19-25 nucleotides in length that have been linked to the development of cancer. Here, we investigated the role of miRNAs in the biology of NPMc+ AML. The miRNA expression was evaluated in 85 adult de novo AML patients characterized for subcellular localization/mutation status of NPM1 and FLT3 mutations using a custom microarray platform. Data were analyzed by using univariate t test within BRB tools. We identified a strong miRNA signature that distinguishes NPMc+ mutated (n = 55) from the cytoplasmic-negative (NPM1 unmutated) cases (n = 30) and includes the up-regulation of miR-10a, miR-10b, several let-7 and miR-29 family members. Many of the down-regulated miRNAs including miR-204 and miR-128a are predicted to target several HOX genes. Indeed, we confirmed that miR-204 targets HOXA10 and MEIS1, suggesting that the HOX up-regulation observed in NPMc+ AML may be due in part by loss of HOX regulators-miRNAs. FLT3-ITD+ samples were characterized by up-regulation of miR-155. Further experiments demonstrated that the up-regulation of miR-155 was independent from FLT3 signaling. Our results identify a unique miRNA signature associated with NPMc+ AML and provide evidence that support a role for miRNAs in the regulation of HOX genes in this leukemia subtype. Moreover, we found that miR-155 was strongly but independently associated with FLT3-ITD mutations.
Project description:Acute Myeloid Leukaemia (AML) carries a 5 year survival rate of just 24%. Toxic chemotherapy regimens remain the backbone of standard of care for AML. The FLT3 tyrosine kinase is a recognised AML oncogene, with FLT3 activating mutations occurring in approximately one third of all AML patients. However, therapeutic targeting of FLT3 has proven difficult as monotherapy, with the development of drug resistance and relapse. Characterisation of the signalling pathways regulated by mutant FLT3 is required to identify better therapeutic strategies.
Project description:Cytogenetically normal acute myeloid leukemia (CN-AML) represents nearly 50% of human acute myeloid leukemia (AML) cases with a 5-year overall survival of approximately 30%. In CN-AML with poorer prognosis, mutations in the de novo DNA methyltransferase (DNMT3A) and the FMS-like tyrosine kinase 3 (Flt3) commonly co-occur (1-3). We demonstrate that mice with Flt3-internal-tandem duplication (Flt3ITD) and inducible deletion of Dnmt3a spontaneously develop a rapidly-lethal, completely-penetrant, and transplantable AML of normal karyotype. These murine AML retain a single Dnmt3a floxed allele, revealing the oncogenic potential of Dnmt3a haploinsufficiency. FLT3-ITD/DNMT3A-mutant primary human and murine AML demonstrate a similar pattern of global DNA methylation. In the murine model, rescuing DNMT3A expression was accompanied by DNA re-methylation and loss of clonogenic potential, suggesting that Dnmt3a-mutant oncogenic effects are reversible. Differentially methylated genomic regions were associated with changes in the expression of nearby genes. Moreover, dissection of the cellular architecture of the AML model using single-cell RNA-Seq, flow cytometry and colony assays identified clonogenic subpopulations that differentially express genes that are sensitive to the methylation of nearby genomic loci and varied in response to Dnmt3a levels. Thus, Dnmt3a haploinsufficiency transforms Flt3ITD myeloproliferative disease by modulating methylation-sensitive gene expression within a clonogenic AML subpopulation. To identify the gene expression changes associated with Dnmt3a loss of function in human and murine Flt3-ITD and Dnmt3a-mutant AML (Single Cell RNA-Seq).