Project description:Genome wide DNA methylation profiling of blood and bone marrow of Pediatric Patients with Relapsed/Refractory Acute Myeloid Leukemia. The Illumina Infinium EPIC Human DNA methylation Beadchip was used to obtain DNA methylation profiles across over 860,000 CpGs.
Project description:Guadecitabine is a second generation DNA methylation inhibitor with improved pharmacokinetics and clinical activity in relapsed/refractory AML (rrAML). Here we report genome-wide DNA methylation profiles in pre-treatment samples from 116 rrAML patients treated at therapeutic doses of guadecitabine in a phase I/II study. Response rate to guadecitabine was 22 % (16CR, 42 12CRi/CRp). There were no strong mutation or methylation predictors of response. Gene expression defined a subset of patients (~20%) that had (i) high DNMT3B and low CDKN2B, CTCF and CDA expression, (ii) enrichment for KRAS/NRAS mutations, (iii) frequent CpG island hypermethylation (iv) low LINE1 hypomethylation after treatment and (v) resistance to guadecitabine in both phase I (response rate 0 % vs 33 %, p=0.07) and phase II components of the study (response rate 5 % vs. 30 %, p=0.02). Multivariate analysis identified peripheral blood blasts and hemoglobin as predictors of response and cytogenetics, gene expression, RAS mutations and hemoglobin as predictors of survival. Thus, a subset of patients (∿ 20%) with rrAML are unlikely to benefit from single agent guadecitabine. In the remaining 80%, guadecitabine is a viable option with a median survival of ∿ 8 months and a three year survival rate of over 20%.
Project description:In high income countries 90% of the patients achieve complete remission after induction chemotherapy. However, 30-40% of these patients suffer from relapse. These patients face a dismal prognosis, as the majority (>60%) of relapsed patients die within 5 years. As a result, outcome for pediatric acute myeloid leukemia (AML) patients remains poor and has stabilized over the past 15 years. To prevent or better treat relapse of AML is the best option to improve outcome. Despite patient specific differences, most patients do respond to initial therapy. This suggests that at relapse, mechanisms are active that cause the altered response to chemotherapy. Detailed understanding of mechanisms that cause relapse remain largely elusive. To gain insight in the molecular pathways that characterize relapsed AML, we performed genome wide gene expression profiling on paired initial diagnosis and relapsed AML samples of 23 pediatric AML patients. We used pathway analysis to find which molecular pathways are involved in altered gene expression between diagnosis and relapse samples of individual AML patients. 23 paired diagnosis and relapse bone marrow or peripheral blood samples were collected and cryo-preserved. They were later thawed and processed for hybridization to Affymetrix U133 Plus 2.0 arrays.
Project description:Relapse is the commonest cause of death in acute myeloid leukaemia (AML), but the mechanisms leading to relapse are unclear. Recently, acquisition of segmental uniparental disomy (UPD) by mitotic recombination (MR) has been reported in 15-20% of AML samples at diagnosis using whole genome single nucleotide polymorphism (SNP) arrays. These cytogenetically invisible abnormalities are associated with homozygous mutations in several types of malignancy. Clonal evolution of heterozygous to homozygous mutations by MR could provide a mechanism for relapse. Experiment Overall Design: DNA from 27 pairs of diagnostic and relapsed AML samples were analysed using Affymetrix 10K SNP arrays. The genotype data of relapsed AML were compared with the data from the corresponding presentation AML.
Project description:In high income countries 90% of the patients achieve complete remission after induction chemotherapy. However, 30-40% of these patients suffer from relapse. These patients face a dismal prognosis, as the majority (>60%) of relapsed patients die within 5 years. As a result, outcome for pediatric acute myeloid leukemia (AML) patients remains poor and has stabilized over the past 15 years. To prevent or better treat relapse of AML is the best option to improve outcome. Despite patient specific differences, most patients do respond to initial therapy. This suggests that at relapse, mechanisms are active that cause the altered response to chemotherapy. Detailed understanding of mechanisms that cause relapse remain largely elusive. To gain insight in the molecular pathways that characterize relapsed AML, we performed genome wide gene expression profiling on paired initial diagnosis and relapsed AML samples of 23 pediatric AML patients. We used pathway analysis to find which molecular pathways are involved in altered gene expression between diagnosis and relapse samples of individual AML patients.
Project description:An increasing body of work reveals aberrant hypermethylation of genes occurring in and potentially contributing to the pathogenesis of myeloid malignancies. Several of these diseases, such as myelodysplastic syndromes (MDS), are responsive to DNA methyltransferase inhibitors. In order to determine the extent of promoter hypermethylation in such tumors we compared the distribution of DNA methylation of 14,000 promoters in MDS and secondary AML patients enrolled in a phase I trial of 5-azacytidine and the histone deacetylase inhibitor entinostat against de novo AML patients and normal CD34+ bone marrow cells. The MDS and secondary AML patients displayed more extensive aberrant DNA methylation involving thousands of genes than did the normal CD34+ bone marrow cells or de novo AML blasts. Aberrant methylation in MDS and secondary AML tended to affect particular chromosomal regions, occurred more frequently in Alu poor genes, and included prominent involvement of genes involved in the WNT and MAPK signaling pathways. DNA methylation was also measured at days 15 and 29 after the first treatment cycle. DNA methylation was reversed at day 15 in a uniform manner throughout the genome, and this effect persisted through day 29, even without continuous administration of the study drugs. Keywords: DNA methylation profiling Direct comparison of DNA methylation in bone marrow samples from patients with Myelodysplastic syndrome or secondary Acute Myeloid Leukemia (AML) at baseline and after in vivo treatment with 5-azacytidine + etinostat. A comparison to de novo normal karyotype AML was also performed. Two control groups were included: one consisting of 8 CD34+ bone marrow samples from healthy donors and a second one consisting of matched CD34+ and CD34- fractions from the bone marrows of 4 healthy donors.