scholarly journals Identification of Two DNMT3A Mutations Compromising Protein Stability and Methylation Capacity in Acute Myeloid Leukemia

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Samantha Bruno ◽  
Maria Teresa Bochicchio ◽  
Eugenia Franchini ◽  
Antonella Padella ◽  
Giovanni Marconi ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Protein Stability ◽  
Myeloid Leukemia ◽  
Stop Codon ◽  
Cpg Methylation ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Single Nucleotide ◽  
Negative Effect ◽  
Acute Myeloid

Somatic mutations of DNMT3A occur in about 20% of acute myeloid leukemia (AML) patients. They mostly consist in heterozygous missense mutations targeting a hotspot site at R882 codon, which exhibit a dominant negative effect and are associated with high myeloblast count, advanced age, and poor prognosis. Other types of mutations such as truncations, insertions, or single-nucleotide deletion also affect the DNMT3A gene, though with lower frequency. The present study aimed to characterize two DNMT3A gene mutations identified by next-generation sequencing (NGS), through analysis of protein stability and DNA methylation status at CpG islands. The first mutation was a single-nucleotide variant of DNMT3A at exon 20 causing a premature STOP codon (c.2385G > A; p.Trp795∗; NM_022552.4). The DNMT3A mutation load increased from 4.5% to 38.2% during guadecitabine treatment, with a dominant negative effect on CpG methylation and on protein expression. The second mutation was a novel insertion of 35 nucleotides in exon 22 of DNMT3A (NM_022552.4) that introduced a STOP codon too, after the amino acid Glu863 caused by a frameshift insertion (c.2586_2587insTCATGAATGAGAAAGAGGACATCTTATGGTGCACT; p. Thr862_Glu863fsins). The mutation, which was associated with reduced DNMT3A expression and CpG methylation, persisted at relapse with minor changes in the methylation profile and at protein level. Our data highlight the need to better understand the consequences of DNMT3A mutations other than R882 substitutions in the leukemogenic process in order to tailor patient treatments, thus avoiding therapeutic resistance and disease relapse.

No Prognostic Impact of the WT1 Gene Single Nucleotide Polymorphism rs16754 in Pediatric Acute Myeloid Leukemia

2010 ◽  
Vol 28 (28) ◽  
pp. e523-e526 ◽  
Author(s):  
Iris H.I.M. Hollink ◽  
Marry M. van den Heuvel-Eibrink ◽  
Martin Zimmermann ◽  
Brian V. Balgobind ◽  
Susan T.C.J.M. Arentsen-Peters ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Prognostic Impact ◽  
Wt1 Gene ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Pediatric Acute Myeloid Leukemia ◽  
Gene Single Nucleotide Polymorphism ◽  
Acute Myeloid

In Silico Identification of Novel Acute Myeloid Leukemia Associated Missense SNPs in Human CEBPA Gene

2020 ◽  
pp. 10-24
Keyword(s):  
Acute Myeloid Leukemia ◽  
In Silico ◽  
Myeloid Leukemia ◽  
Gene Interaction ◽  
Nucleotide Polymorphisms ◽  
Future Perspectives ◽  
Single Nucleotide ◽  
In Silico Identification ◽  
And Function ◽  
Acute Myeloid

Single nucleotide polymorphisms (SNPs) in CEBPA gene have been found to be associated with cancer especially Acute Myeloid Leukemia (AML). Therefore, the identification of functional and structural polymorphisms in CEBPA is important to study and discover therapeutics targets and potential malfunctioning. For this purpose, several bioinformatics tools were used for the identification of disease-associated nsSNPs, which might be vital for the structure and function of CEBPA, making them extremely important. In silico tools used in this study included SIFT, PROVEAN, PolyPhen2, SNP&GO and PhD-SNP, followed by ConSurf and I-Mutant. Protein 3D modelling was carried out using I-TASSER and MODELLER v9.22, while GeneMANIA and string were used for the prediction of gene-gene interaction in this regard. From our study, we found that the L345P, R333C, R339Q, V328G, R327W, L317Q, N292S, E284A, R156W, Y108N and F82L mutations were the most crucial SNPs. Additionally, the gene-gene interaction showed the genes having correlation with CEBPA’s co-expressions and importance in several pathways. In future, these 11 mutations should be investigated while studying diseases related to CEBPA, especially for AML. Being the first of its kind, future perspectives are proposed in this study, which will help in precision medicine. Animal models are of great significance in finding out CEBPA effects in disease.

scholarly journals STAT3β is a tumor suppressor in acute myeloid leukemia

2019 ◽  
Vol 3 (13) ◽  
pp. 1989-2002 ◽  
Author(s):  
Petra Aigner ◽  
Tatsuaki Mizutani ◽  
Jaqueline Horvath ◽  
Thomas Eder ◽  
Stefan Heber ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Messenger Rna ◽  
Myeloid Leukemia ◽  
Dominant Negative ◽  
Expression Ratio ◽  
Mrna Ratio ◽  
Dominant Negative Form ◽  
Alternatively Spliced ◽  
Regulatory Functions ◽  
Acute Myeloid

Abstract Signal transducer and activator of transcription 3 (STAT3) exists in 2 alternatively spliced isoforms, STAT3α and STAT3β. Although truncated STAT3β was originally postulated to act as a dominant-negative form of STAT3α, it has been shown to have various STAT3α-independent regulatory functions. Recently, STAT3β gained attention as a powerful antitumorigenic molecule in cancer. Deregulated STAT3 signaling is often found in acute myeloid leukemia (AML); however, the role of STAT3β in AML remains elusive. Therefore, we analyzed the STAT3β/α messenger RNA (mRNA) expression ratio in AML patients, where we observed that a higher STAT3β/α mRNA ratio correlated with a favorable prognosis and increased overall survival. To gain better understanding of the function of STAT3β in AML, we engineered a transgenic mouse allowing for balanced Stat3β expression. Transgenic Stat3β expression resulted in decelerated disease progression and extended survival in PTEN- and MLL-AF9–dependent AML mouse models. Our findings further suggest that the antitumorigenic function of STAT3β depends on the tumor-intrinsic regulation of a small set of significantly up- and downregulated genes, identified via RNA sequencing. In conclusion, we demonstrate that STAT3β plays an essential tumor-suppressive role in AML.

CpG methylation analysis of the MEG3 and SNRPN imprinted genes in acute myeloid leukemia and myelodysplastic syndromes

2010 ◽  
Vol 34 (2) ◽  
pp. 148-153 ◽  
Author(s):  
Leonidas Benetatos ◽  
Eleftheria Hatzimichael ◽  
Aggeliki Dasoula ◽  
George Dranitsaris ◽  
Stavroula Tsiara ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndromes ◽  
Myeloid Leukemia ◽  
Cpg Methylation ◽  
Imprinted Genes ◽  
Methylation Analysis ◽  
Acute Myeloid

Acute Myeloid Leukemia with Deletion 9q Is Associated with CEBPA Loss-of-Function Mutations.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2896-2896
Author(s):  
Stefan Frohling ◽  
Richard F. Schlenk ◽  
Jurgen Krauter ◽  
Arnold Ganser ◽  
Christian Thiede ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Mutational Analysis ◽  
Good Prognosis ◽  
Dominant Negative ◽  
Binding Potential ◽  
Complex Karyotype ◽  
Loss Of Function ◽  
Cebpa Mutations ◽  
Acute Myeloid

Abstract The transcription factor CCAAT/enhancer binding protein alpha (C/EBPalpha) plays an important role in the development of mature neutrophils. Two common types of mutations in the CEBPA gene encoding C/EBPalpha have been identified in approximately 10% of adults with acute myeloid leukemia (AML): N-terminal, dominant-negative frameshift mutations that result in loss of C/EBPalpha function and C-terminal in-frame mutations that result in C/EBPalpha proteins with decreased DNA-binding potential. Previous studies concluded that mutant CEBPA predicts favorable outcome in younger AML patients with intermediate-risk karyotypes or normal cytogenetics. To assess the prevalence of CEBPA mutations in specific cytogenetic subgroups, mutational analysis of the CEBPA gene was performed in 125 AML patients. No CEBPA mutations were detected in 77 patients with t(8;21), inv(16)/t(16;16), t(15;17), or balanced translocations with breakpoints in band 11q23. In 58 patients with various non-complex karyotypic abnormalities, CEBPA mutations were present in 8 (14%). Surprisingly, 5 of the 8 patients with del(9q) as the sole aberration or in combination with a single additional abnormality other than t(8;21) had CEBPA mutations associated with loss of C/EBPalpha function. Consequently, 41 additional del(9q) cases were analyzed; 9 had CEBPA loss-of-function mutations. The overall prevalence of CEBPA loss-of-function mutations in cases with del(9q) within a non-complex karyotype was 41% (14 of 34 patients), whereas none of the patients who had a del(9q) within a complex karyotype (n = 7), in combination with a t(8;21) (n = 10), or together with a t(15;17) (n = 1) demonstrated mutant CEBPA. Analysis of associated mutations indicated that alterations of the FLT3, MLL, and NRAS genes are not common cooperating events in the pathogenesis of del(9q) AML with inactivating CEBPA mutations. This is the first study to show that AML with del(9q) is strongly associated with CEBPA loss-of-function mutations. The coincidence of del(9q) with inactivating CEBPA mutations and the fact that del(9q) is a common secondary cytogenetic abnormality in t(8;21)-positive AML, that is characterized by specific down-regulation of CEBPA, raise the possibility that loss of a critical segment of 9q, most likely in 9q22, and disruption of C/EBPalpha function cooperate in the pathogenesis of these leukemias. Further refinement of the commonly deleted segment of 9q using high-resolution techniques is underway to identify the critical gene(s) involved and their role in normal hematopoiesis and leukemogenesis. A collaborative intergroup study has been initiated to define whether the relatively good prognosis associated with del(9q) is related to the presence of a CEBPA mutation.

The Critical Role of Peptidyl-Prolyl cis/trans Isomerase, Pin1 in Acute Myeloid Leukemia with C/EBPalpha Mutations.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2213-2213
Author(s):  
J. Pulikkan ◽  
A. Peer Zada ◽  
M. Geletu ◽  
V. Dengler ◽  
Daniel G. Tenen ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Dominant Negative ◽  
Pcr Analysis ◽  
Wild Type ◽  
Rt Pcr ◽  
Promoter Assay ◽  
Type C ◽  
Acute Myeloid

Abstract CCAAT enhancer binding protein alpha (C/EBPα) is a myeloid specific transcription factor that coordinates cellular differentiation and cell cycle arrest. Loss of C/EBPα expression or function in leukemic blasts contributes to a block in myeloid cell differentiation. C/EBPα is mutated in around 9% of acute myeloid leukemia (AML). The mutations reported in C/EBPα are frame shift mutations and point mutations at basic region Leucine zipper. The mutant form of C/EBPα ie C/EBPα-p30 exhibits dominant negative function over the wild type protein. The role of peptidyl-prolyl cis/trans isomerase, Pin1 in tumorogenesis and its overexpression in many cancers led us to investigate its role in acute myeloid leukemia with C/EBPα mutation. Here we show that Pin1 is upregulated in patients with acute myeloid leukemia by affymetrix analysis. By quantitative Real-Time RT-PCR analysis, we show C/EBPα-p30 could induce Pin1 transcription, while the wild type C/EBPα downregulates Pin1 expression. Luciferase promoter assay for the Pin1 promoter shows that wild type C/EBPα is able to block Pin1 promoter activity. Mean while, C/EBPα-p30 couldn’t block Pin1 promotor activity. By silencing Pin1 by RNA Interference as well as with inhibitor against Pin1 (PiB) we could show myeloid differentiation in human CD34+ cord blood cells as well as in Kasumi-6 cells as assessed by FACS analysis with granulocytic markers. We investigated the mechanism underlying the dominant negative action of C/EBPα-p30 over the wild type protein. We report that Pin1 increases the transcriptional activity of the oncogene c-jun. We also show that c-jun blocks the DNA binding and transactivation of C/EBPα protein as assessed by gel shift assay and promoter assay respectively. We have previously shown that c-jun expression is high in AML patients with C/EBPα mutation and c-jun could block C/EBPα function by protein-protein interaction. Quantitative Real-Time RT-PCR analysis shows that inhibition of Pin1 by the inhibitor PiB downregulates c-jun mRNA expression. In conclusion, inhibition of Pin1 leads to granulocytic differentiation. Our results show Pin1 as a novel target in treating AML patients with C/EBPα mutation.

scholarly journals Mutational spectrum analysis of chronic myelomonocytic leukemia includes genes associated with epigenetic regulation: UTX, EZH2, and DNMT3A

Blood ◽  
2011 ◽  
Vol 118 (14) ◽  
pp. 3932-3941 ◽  
Author(s):  
Anna M. Jankowska ◽  
Hideki Makishima ◽  
Ramon V. Tiu ◽  
Hadrian Szpurka ◽  
Yun Huang ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chronic Myelomonocytic Leukemia ◽  
Molecular Heterogeneity ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Mutant Genotype ◽  
Myelomonocytic Leukemia ◽  
Acute Myeloid

Abstract Chronic myelomonocytic leukemia (CMML), a myelodysplastic/myeloproliferative neoplasm, is characterized by monocytic proliferation, dysplasia, and progression to acute myeloid leukemia. CMML has been associated with somatic mutations in diverse recently identified genes. We analyzed 72 well-characterized patients with CMML (N = 52) and CMML-derived acute myeloid leukemia (N = 20) for recurrent chromosomal abnormalities with the use of routine cytogenetics and single nucleotide polymorphism arrays along with comprehensive mutational screening. Cytogenetic aberrations were present in 46% of cases, whereas single nucleotide polymorphism array increased the diagnostic yield to 60%. At least 1 mutation was found in 86% of all cases; novel UTX, DNMT3A, and EZH2 mutations were found in 8%, 10%, and 5.5% of patients, respectively. TET2 mutations were present in 49%, ASXL1 in 43%, CBL in 14%, IDH1/2 in 4%, KRAS in 7%, NRAS in 4%, and JAK2 V617F in 1% of patients. Various mutant genotype combinations were observed, indicating molecular heterogeneity in CMML. Our results suggest that molecular defects affecting distinct pathways can lead to similar clinical phenotypes.

Single Nucleotide Polymorphism in the Mutational Hotspot of WT1 Predicts a Favorable Outcome in Patients With Cytogenetically Normal Acute Myeloid Leukemia

2010 ◽  
Vol 28 (4) ◽  
pp. 578-585 ◽  
Author(s):  
Frederik Damm ◽  
Michael Heuser ◽  
Michael Morgan ◽  
Haiyang Yun ◽  
Anika Großhennig ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Acute Myeloid Leukemia ◽  
Healthy Volunteers ◽  
Myeloid Leukemia ◽  
Minor Allele ◽  
Risk Marker ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Risk Patients ◽  
Acute Myeloid

Purpose We assessed the prognostic impact of a known single nucleotide polymorphism (SNP) located in the mutational hotspot of WT1 in patients with cytogenetically normal acute myeloid leukemia (CN-AML) in the context of other prognostic markers. Patients and Methods WT1 exons 7 and 9 from 249 CN-AML patients from multicenter treatment trials AML-SHG Hannover 0199 (Clinical Trials Identifier NCT00209833) and 0295, and 50 healthy volunteers were analyzed by direct sequencing. NPM1, FLT3, CEBPA, and MLL were assessed for mutations and WT1 expression was quantified. Results The minor allele of SNP rs16754 (WT1AG/GG) was found in 25.7% of CN-AML patients' blasts and germline DNA and in 36% of healthy volunteers. Patient characteristics, frequencies of mutations, or WT1 expression levels were similarly distributed between patients homozygous for the major allele compared with patients heterozygous or homozygous for the minor allele. SNP rs16754 status was an independent predictor of relapse-free survival (RFS; hazard ratio [HR], 0.49; 95% CI, 0.3 to 0.81; P = .005) and overall survival (OS; HR, 0.44; 95% CI, 0.27 to 0.74; P = .002) in multivariate analysis. The favorable effect of SNP rs16754 was stronger in NPM1/FLT3-ITD (internal tandem duplication of the FLT3 gene) high-risk patients compared with NPM1/FLT3-ITD low-risk patients. Favorable prognosis could not be identified by any other known low-risk marker in half the patients with at least one minor allele (13% of all patients). No difference for complete remission rate, RFS, or OS was found between patients with or without acquired WT1 mutations. Conclusion WT1 SNP rs16754 may be a novel independent favorable-risk marker in CN-AML patients that might improve risk and treatment stratification.

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