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:Acute myeloid leukemia (AML) originates from malignant, immature myeloid progenitor cells that differentiate into dysfunctional myeloblasts. While cytarabine (Ara-C) and daunorubicin (DNR)-based chemotherapy regimens are the standard treatments, approximately 10-40% of AML patients under the age of 60 and 40-60% over 60 do not respond, leading to refractory or relapsed (R/R) AML. Targeted chemotherapy for FLT3-ITD mutated R/R AML cells improves response rates and survival outcomes in FLT3-ITD mutated R/R AML patients. However, patients with wild-type FLT3 R/R AML remain therapeutically challenged, with persistent difficulty in finding effective treatments. Better insights on the fundamental understanding of treatment failure in wild-type FLT3 AML cells are needed to enhance therapeutic outcomes. However, precise mechanisms behind the treatment failure remain unclear. This study investigates the mechanisms underlying the failure of Ara-C and DNR-based chemotherapy in wild-type FLT3 R/R AML. Using RHI-1 cells, a wild-type FLT3 AML cell line with Ara-C resistance, we demonstrated that Ara-C resistance-mediated DNR tolerance did not result from reducing the concentration of DNR in RHI-1 cells, but rather from interrupting the cytotoxic mechanisms of DNR through the Ara-C resistance of RHI-1. The down-regulated deoxycytidine kinase (DCK) in RHI-1 cells interrupted mechanisms of Ara-C cytotoxic action. Also, the down-regulation of DCK enhanced mitochondrial metabolic pathways, DNA repair process, and ROS detoxification. Through these pathways, RHI-1 cells exhibit tolerance under DNR treatment. Among these enhanced processes, targeting mitochondrial metabolism, particularly OXPHOS complex I proteins, improved the efficacy of both Ara-C and DNR. Our findings shed light on a potential mechanism underlying the treatment failure and the role of mitochondrial metabolism in wild-type FLT3 R/R AML cells.
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.