Low-penetrance genetic susceptibility and resistance loci implicated in the relative risk for radiation-induced acute myeloid leukemia in mice

Blood ◽  
2003 ◽  
Vol 101 (6) ◽  
pp. 2349-2354 ◽  
Author(s):  
Emma Boulton ◽  
Clare Cole ◽  
Abigail Knight ◽  
Helen Cleary ◽  
Roger Snowden ◽  
...  

Inbred CBA/H mice are susceptible to radiation-induced acute myeloid leukemia (r-AML), and C57BL/6 mice are resistant. A genome-wide screen for linkage between genotype and phenotype (r-AML) of 67 affected (CBA/H × C57BL/6)F1 × CBA/H backcross mice has revealed at least 2 suggestive loci that contribute to the overall lifetime risk for r-AML. Neither is necessary or sufficient for r-AML, but relative risk is the net effect of susceptibility (distal chromosome 1) and resistance (chromosome 6) loci. An excess of chromosome 6 aberrations in mouse r-AML and bone marrow cells up to 6 months after irradiation in vivo suggests the locus confers a proliferative advantage during the leukemogenic process. The stem cell frequency regulator 1 (Scfr1) locus maps to distal chromosome 1 and determines the frequency of hemopoietic stem cells (HSCs) in inbred mice, suggesting that target size may be one factor in determining the relative susceptibility of inbred mice to r-AML.

2016 ◽  
Vol 113 (43) ◽  
pp. E6669-E6678 ◽  
Author(s):  
Mark A. Gregory ◽  
Angelo D’Alessandro ◽  
Francesca Alvarez-Calderon ◽  
Jihye Kim ◽  
Travis Nemkov ◽  
...  

Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are common in acute myeloid leukemia (AML) and drive leukemic cell growth and survival. Although FLT3 inhibitors have shown considerable promise for the treatment of AML, they ultimately fail to achieve long-term remissions as monotherapy. To identify genetic targets that can sensitize AML cells to killing by FLT3 inhibitors, we performed a genome-wide RNA interference (RNAi)-based screen that identified ATM (ataxia telangiectasia mutated) as being synthetic lethal with FLT3 inhibitor therapy. We found that inactivating ATM or its downstream effector glucose 6-phosphate dehydrogenase (G6PD) sensitizes AML cells to FLT3 inhibitor induced apoptosis. Examination of the cellular metabolome showed that FLT3 inhibition by itself causes profound alterations in central carbon metabolism, resulting in impaired production of the antioxidant factor glutathione, which was further impaired by ATM or G6PD inactivation. Moreover, FLT3 inhibition elicited severe mitochondrial oxidative stress that is causative in apoptosis and is exacerbated by ATM/G6PD inhibition. The use of an agent that intensifies mitochondrial oxidative stress in combination with a FLT3 inhibitor augmented elimination of AML cells in vitro and in vivo, revealing a therapeutic strategy for the improved treatment of FLT3 mutated AML.


2013 ◽  
Vol 20 (5) ◽  
pp. 1135-1145 ◽  
Author(s):  
Sophia Adamia ◽  
Benjamin Haibe-Kains ◽  
Patrick M. Pilarski ◽  
Michal Bar-Natan ◽  
Samuel Pevzner ◽  
...  

Haematologica ◽  
2020 ◽  
Author(s):  
Alisa Damnernsawad ◽  
Daniel Bottomly ◽  
Stephen E. Kurtz ◽  
Christopher A. Eide ◽  
Shannon K. McWeeney ◽  
...  

Drug resistance impedes the long-term effect of targeted therapies in acute myeloid leukemia (AML), necessitating the identification of mechanisms underlying resistance. Approximately 25% of AML patients carry FLT3 mutations and develop post-treatment insensitivity to FLT3 inhibitors, including sorafenib. Using a genome-wide CRISPR screen, we identified LZTR1, NF1, TSC1 or TSC2, negative regulators of the MAPK and MTOR pathways, as mediators of sorafenib resistance. Analyses of ex vivo drug sensitivity assays in FLT3-ITD AML patient samples revealed lower expression of LZTR1, NF1, and TSC2 correlated with sorafenib sensitivity. Importantly, MAPK and/or MTOR complex1 (MTORC1) activity were upregulated in AML cells made resistant to several FLT3 inhibitors, including crenolanib, quizartinib, or sorafenib. These cells were sensitive to MEK inhibitors, and the combination of FLT3 and MEK inhibitors showed enhanced efficacy, suggesting its effectiveness in AML patients with FLT3 mutations and those with resistance to FLT3 inhibitors.


Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 4011-4013 ◽  
Author(s):  
Robert Hromas ◽  
Rinah Shopnick ◽  
Hani George Jumean ◽  
Charles Bowers ◽  
Marileila Varella-Garcia ◽  
...  

Abstract AML1 is a transcriptional activator that is essential for normal hematopoietic development. It is the most frequent target for translocations in acute leukemia. We recently identified 3 patients in whom pancytopenia developed almost 50 years after high-level radiation exposure from nuclear explosions during or after World War II. In all 3 patients, acute myeloid leukemia (AML) eventually developed that had similar characteristics and clinical courses. Cytogenetics from the 3 patients revealed a t(1;21)(p36;q22), a t(18;21)(q21;q22), and a t(19;21)(q13.4;q22). By fluorescent in situ hybridization (FISH), all 3 translocations disrupted the AML1 gene. Two of theseAML1 translocations, the t(18;21) and the t(19;21), have not been reported previously. It is possible that the AML1 gene is a target for radiation-induced AML.


Blood ◽  
1997 ◽  
Vol 89 (7) ◽  
pp. 2537-2545 ◽  
Author(s):  
Nechama Haran-Ghera ◽  
Rita Krautghamer ◽  
Tsvee Lapidot ◽  
Alpha Peled ◽  
Melissa G. Dominguez ◽  
...  

Abstract The SJL/J mouse strain has a high spontaneous incidence of a B-cell neoplasm, reticulum cell neoplasm type B (RCN B). In addition, following irradiation, 10% to 30% of these mice develop acute myelomonocytic leukemia (radiation-induced acute myeloid leukemia [RI-AML]), an incidence that can be increased to 50% by treatment of the mice with corticosteroids after irradiation. The role played by the mononuclear phagocyte growth factor, colony-stimulating factor-1 (CSF-1), in the development of RI-AML in SJL/J mice was investigated. Mice dying of RI-AML, but not those dying of RCN B or without disease, possessed elevated concentrations of circulating CSF-1. In addition, in mice developing RI-AML with a more prolonged latency, circulating CSF-1 concentrations were increased before overt expression of RI-AML. First-passage tumors from 14 different RI-AMLs all contained high concentrations of CSF-1, and six of six different first- or second-passage tumors expressed the CSF-1 receptor (CSF-1R). Furthermore, in vitro colony formation by first- or second-passage tumor cells from 20 of 20 different RI-AMLs was blocked by neutralizing anti–CSF-1 antibody, and four of four of these tumors were inhibited by anti–CSF-1R antibody. The results of these antibody neutralization studies, coupled with the observation of elevated circulating CSF-1 in mice developing RI-AML, show an autocrine role for CSF-1 in RI-AML development in SJL/J mice. Southern blot analysis of tumor DNA from six of six of these tumors failed to reveal any rearrangements in the genes for CSF-1 or the CSF-1R. Studies in humans have shown that patients with AML possess elevated levels of circulating CSF-1 and that AML cells can express CSF-1 and the CSF-1R. Thus, RI-AML in the SJL/J mouse appears to be a useful model for human AML.


Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 4011-4013 ◽  
Author(s):  
Robert Hromas ◽  
Rinah Shopnick ◽  
Hani George Jumean ◽  
Charles Bowers ◽  
Marileila Varella-Garcia ◽  
...  

AML1 is a transcriptional activator that is essential for normal hematopoietic development. It is the most frequent target for translocations in acute leukemia. We recently identified 3 patients in whom pancytopenia developed almost 50 years after high-level radiation exposure from nuclear explosions during or after World War II. In all 3 patients, acute myeloid leukemia (AML) eventually developed that had similar characteristics and clinical courses. Cytogenetics from the 3 patients revealed a t(1;21)(p36;q22), a t(18;21)(q21;q22), and a t(19;21)(q13.4;q22). By fluorescent in situ hybridization (FISH), all 3 translocations disrupted the AML1 gene. Two of theseAML1 translocations, the t(18;21) and the t(19;21), have not been reported previously. It is possible that the AML1 gene is a target for radiation-induced AML.


2015 ◽  
Vol 32 (1) ◽  
pp. 77-79 ◽  
Author(s):  
Monika Gupta ◽  
Nita Radhakrishnan ◽  
Manoranjan Mahapatra ◽  
Renu Saxena

2020 ◽  
Author(s):  
Meng Liu ◽  
Yuan Ren ◽  
Xianfu Wang ◽  
Xianglan Lu ◽  
Ming Li ◽  
...  

Abstract Background: Acute myeloid leukemia (AML) is a complex hematological disease characterized by genetic and clinical heterogeneity. The identification and understanding of chromosomal abnormalities are important for the diagnosis and management of AML patients. Compared to recurrent chromosomal translocations in AML, t(8;16)(p11.2;p13.3) can be found in any age group, but is very rare and typically associated with poor prognosis. Methods: Conventional cytogenetic studies were performed among 1,824 AML patients from our oncology database in the last 20 years. Fluorescence in situ hybridization (FISH) was carried out to demonstrate the translocation fusion. Array comparative genome hybridization (aCGH) was carried out to further characterize the duplication of chromosomes.Results: We identified three AML patients with t(8;16)(p11.2;p13.3) by chromosome analysis. Two of the three patients with additional 1q duplication were detected by FISH and aCGH. aCGH characterized a 46.7 Mb and 49.9 Mb gain of chromosome 1 at bands q32.1q44 in these two patients, respectively. One patient achieved a complete remission (CR) but relapsed three months later. The other patient never experienced a CR and died two years after diagnosis. Conclusion: 1q duplication were detected in two of three AML patients with t(8;16)(p11.2;p13.3), suggesting that 1q duplication can be a recurrent event in AML patients with t(8;16). In concert with the findings of previous studies of similar patients, our work suggests that 1q duplication may also be an unfavorable prognostic factor of the disease.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 204
Author(s):  
Adewale J. Ogunleye ◽  
Ekaterina Romanova ◽  
Yulia A. Medvedeva

Background: Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by genetic and epigenetic aberrations that alter the differentiation capacity of myeloid progenitor cells. The transcription factor CEBPα is frequently mutated in AML patients leading to an increase in DNA methylation in many genomic locations. Previously, it has been shown that ecCEBPα (extra coding CEBPα) - a lncRNA transcribed in the same direction as CEBPα gene - regulates DNA methylation of CEBPα promoter in cis. Here, we hypothesize that ecCEBPα could participate in the regulation of DNA methylation in trans. Method: First, we retrieved the methylation profile of AML patients with mutated CEBPα locus from The Cancer Genome Atlas (TCGA). We then predicted the ecCEBPα secondary structure in order to check the potential of ecCEBPα to form triplexes around CpG loci and checked if triplex formation influenced CpG methylation, genome-wide. Results: Using DNA methylation profiles of AML patients with a mutated CEBPα locus, we show that ecCEBPα could interact with DNA by forming DNA:RNA triple helices and protect regions near its binding sites from global DNA methylation. Further analysis revealed that triplex-forming oligonucleotides in ecCEBPα are structurally unpaired supporting the DNA-binding potential of these regions. ecCEBPα triplexes supported with the RNA-chromatin co-localization data are located in the promoters of leukemia-linked transcriptional factors such as MLF2. Discussion: Overall, these results suggest a novel regulatory mechanism for ecCEBPα as a genome-wide epigenetic modulator through triple-helix formation which may provide a foundation for sequence-specific engineering of RNA for regulating methylation of specific genes.


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