Mechanism of Altered Nucleo-Cytoplasmic Traffic of Nucleophosmin in Acute Myelogenous Leukemia Carrying Exon-12 NPM Mutations (NPMc+ AML).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4396-4396
Author(s):  
Brunangelo Falini ◽  
Niccolo Bolli ◽  
Jing Shan ◽  
Maria Paola Martelli ◽  
Ildo Nicoletti ◽  
...  
Keyword(s):  
Acute Myelogenous Leukemia ◽  
Nuclear Export ◽  
Mutational Analysis ◽  
Nuclear Export Signal ◽  
Normal Karyotype ◽  
Myelogenous Leukemia ◽  
Wild Type ◽  
Nuclear Localization Signals ◽  
Tryptophan Residues ◽  
Acute Myelogenous

Abstract We recently found that about one-third of adult AML (60% of all AML with normal karyotype) display aberrant cytoplasmic expression of nucleophosmin (NPM) which is due to mutations occurring at the exon-12 of NPM gene (Falini B, et al., Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype..N Engl J Med2005; 352: 254–266). Hereby, we clarify the molecular mechanism underlying cytoplasmic NPM accumulation that yet remained to be elucidated. AML-associated mutated NPM alleles encode abnormal NPM proteins (25 mutants so far identified) which have acquired at the C-terminus a nuclear export signal-(NES) motif and lost at least one of tryptophan residues 288 and 290 which determine nucleolar localization. Both alterations are crucial for mutant NPM export from nucleus to cytoplasm. In fact, the cytoplasmic NPM accumulation is blocked by leptomycin-B and ratjadones which are specific inhibitors of exportin-1/CRM1, and by re-insertion of tryptophan residues 288 and 290, which respectively relocate NPM mutants in the nucleoplasm and nucleoli. Thus, for cytoplasmic accumulation of NPM to occur, the NES motif and tryptophan mutations must act in concert. Possibly, when NPM mutans enter the nucleus by virtue of their nuclear localization signals (NLS), their capability to bind nucleoli must be hindered at least partially to become a CRM-1 target. Specific antibodies anti-NPM mutant proteins showed that the mutants localized exclusively in the cytoplasm and recruited in that site the wild-type NPM protein which is physiologically located in the nucleoli. These findings suggest that the NPM mutants may interfere with the functions of wild-type NPM and possibly contribute to leukemogenesis. Immunostaining of 393 AML cases using anti-NPM monoclonal antibodies predicted the presence of NPM exon-12 mutations in all 191 NPM-cytoplasmic positive cases. This finding is consistent with the fact that, despite genomic heterogeneity, all NPM mutants contain a NES motif which, in the presence of altered tryptophans, promotes their rapid export from the nucleus to the cytoplasm. The immunohistochemical test is diagnostically relevant since it can be used as simple first-step procedure in molecular-genetic characterization of AML and as a surrogate for mutational analysis in selected cases. These findings are also clinically relevant since cytoplasmic NPM/NPM mutations are predictors of good response to induction therapy and favourable prognosis in AML with a normal karyotype.

Cytoplasmic Nucleophosmin in Acute Myelogenous Leukemia with a Normal Karyotype

2005 ◽  
Vol 352 (3) ◽  
pp. 254-266 ◽  
Author(s):  
Brunangelo Falini ◽  
Cristina Mecucci ◽  
Enrico Tiacci ◽  
Myriam Alcalay ◽  
Roberto Rosati ◽  
...  
Keyword(s):  
Acute Myelogenous Leukemia ◽  
Normal Karyotype ◽  
Myelogenous Leukemia ◽  
Acute Myelogenous

A Phase II Study of Midostaurin and 5-Azacitidine for Untreated Elderly and Unfit Patients With FLT3 Wild-type Acute Myelogenous Leukemia

2020 ◽  
Vol 20 (4) ◽  
pp. 226-233.e1
Author(s):  
Benjamin K. Tomlinson ◽  
Molly M. Gallogly ◽  
Donna M. Kane ◽  
Leland Metheny ◽  
Hillard M. Lazarus ◽  
...  
Keyword(s):  
Phase Ii ◽  
Acute Myelogenous Leukemia ◽  
Phase Ii Study ◽  
Myelogenous Leukemia ◽  
Wild Type ◽  
Acute Myelogenous ◽  
Unfit Patients

scholarly journals Mutation of the p53 gene in human acute myelogenous leukemia

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1500-1507 ◽  
Author(s):  
JM Slingerland ◽  
MD Minden ◽  
S Benchimol
Keyword(s):  
Acute Myelogenous Leukemia ◽  
P53 Protein ◽  
Point Mutations ◽  
P53 Gene ◽  
Myelogenous Leukemia ◽  
Wild Type ◽  
P53 Expression ◽  
Coding Sequence ◽  
Acute Myelogenous ◽  
Blast Cells

Abstract Heterogeneity of p53 protein expression is seen in blast cells of patients with acute myelogenous leukemia (AML). p53 protein is detected in the blasts of certain AML patients but not in others. We have identified p53 protein variants with abnormal mobility on gel electrophoresis and/or prolonged half-life (t 1/2). We have sequenced the p53 coding sequence from primary blast cells of five AML patients and from the AML cell line (OCIM2). In OCIM2, a point mutation in codon 274 was identified that changes a valine residue to aspartic acid. A wild type p53 allele was not detected in these cells. Two point mutations (codon 135, cysteine to serine; codon 246, methionine to valine) were identified in cDNA from blasts of one AML patient. Both mutations were present in blast colonies grown from single blast progenitor cells, indicating that individual leukemia cells had sustained mutation of both p53 alleles. The cDNAs sequenced from blast samples of four other patients, including one with prolonged p53 protein t 1/2 and one with no detectable p53 protein, were fully wild type. Thus, the heterogeneity of p53 expression cannot be explained in all cases by genetic change in the p53 coding sequence. The prolonged t 1/2 of p53 protein seen in some AML blasts may therefore reflect changes not inherent to p53. A model is proposed in which mutational inactivation of p53, although not required for the evolution of neoplasia, would confer a selective advantage, favoring clonal outgrowth during disease progression.

Association of cis-Acting rs530 of the ETS2 Transcriptional Factor Gene with High-Risk Acute Myelogenous Leukemia (AML) and Allelic Expression Imbalance Assessment.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2230-2230
Author(s):  
Il-Kwon Lee ◽  
Jeong-Hwa Choi ◽  
Hee Nam Kim ◽  
Yeo-Kyeoung Kim ◽  
Kyeong-Soo Park ◽  
...  
Keyword(s):  
High Risk ◽  
Secondary Structure ◽  
Acute Myelogenous Leukemia ◽  
Myelogenous Leukemia ◽  
Wild Type ◽  
Heterozygous Genotype ◽  
Factor Gene ◽  
Cis Acting ◽  
Increased Risk ◽  
Acute Myelogenous

Abstract We have previously implicated ETS2 in the etiopathogenesis of acute myeloid leukemia through case-control study by revealing that polymorphisms of ETS2, a hematopoietic transcription factor gene is associated with increased risk to acute myelogenous leukemia (AML). Two SNPs out of 7 genotyped sites, rs711 and rs530 were shown to be associated with increased risk to AML with the odds ratio (OR) of 1.76 (95% C.I. 1.2–2.5, p=0.0019) for rs711 and 1.67 (95% C.I. 1.3–2.2, p=0.0003) for rs530 relative to wild type genotypes respectively. Haplotype and linkage disequilibrium (LD) map was estimated, but haplotype association was not found with statistical significance. Korean LD structure was similar to Japanese LD, but least similarity was shown with LDs from African (Yoruba in Ibadan, Nigeria). Since these two SNPs are located in the 3′ UTR region we simulated the change in secondary structure in silico of the 3′ UTR region with two variants introduced in the sequence. Most dramatic change in the secondary structure was observed in the rs530 containing domain suggesting this variant of being cis-acting genetic variant. Real time Q-PCR and western blot analysis showed that expression of ETS2 decreased in individuals with heterozygous or mutant homozygous genotypes, showing most abundant expression with two wild type copies of rs530, less expression with the rare homozygous or heterozygous genotype. Sequencing cDNA of 55 heterozygous AML patients revealed mRNA expression imbalance in 13 cases (24%) effectively reverting heterozygous genotype to homozygous wild type mRNA species. The detection of a discrepancy between the mRNA alleles of rs530 clearly proves cis-acting effect of rs530. However there was not a case in 51 healthy control samples suggesting differing transcript levels derived from the two alleles of an autosomal gene is disease-specific phenomena. Taken together, our results suggest that two polymorphic variants in the 3′ UTR region predispose individual to high-risk AML by inducing change in mRNA expression as a cis-acting variant.

scholarly journals Mutational analysis of therapy-related myelodysplastic syndromes and acute myelogenous leukemia

Haematologica ◽  
2013 ◽  
Vol 98 (6) ◽  
pp. 908-912 ◽  
Author(s):  
A. H. Shih ◽  
S. S. Chung ◽  
E. K. Dolezal ◽  
S.-J. Zhang ◽  
O. I. Abdel-Wahab ◽  
...  
Keyword(s):  
Myelodysplastic Syndromes ◽  
Acute Myelogenous Leukemia ◽  
Mutational Analysis ◽  
Myelogenous Leukemia ◽  
Acute Myelogenous

Nucleophosmin gene mutations are predictors of favorable prognosis in acute myelogenous leukemia with a normal karyotype

Blood ◽  
2005 ◽  
Vol 106 (12) ◽  
pp. 3733-3739 ◽  
Author(s):  
Susanne Schnittger ◽  
Claudia Schoch ◽  
Wolfgang Kern ◽  
Cristina Mecucci ◽  
Claudia Tschulik ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Acute Myelogenous Leukemia ◽  
Gene Mutations ◽  
Normal Karyotype ◽  
Kinase Domain ◽  
Myelogenous Leukemia ◽  
Tyrosine Kinase Domain ◽  
Double Positive ◽  
Acute Myelogenous ◽  
Cebpa Mutations

Nucleophosmin (NPM1) exon-12 gene mutations are the hallmark of a large acute myelogenous leukemia (AML) subgroup with normal karyotype, but their prognostic value in this AML subset has not yet been determined. We screened 401 AML patients with normal karyotype treated within the German AML Cooperative Group Protocol 99 (AMLCG99) study for NPM1 mutations. Results were related with partial tandem duplications within the MLL gene (MLL-PTD), Fms-like tyrosine kinase 3–length mutations (FLT3-LM), the tyrosine kinase domain of FLT3 (FLT3-TKD), NRAS, KIT, and CEBPA mutations and with clinical characteristics and outcome. NPM1 mutations were detected in 212 (52.9%) of 401 patients. Fourteen mutations, including 8 new variants, were identified. NPM1-mutated cases associated frequently with FLT3 mutations but rarely with other mutations. The NPM1-mutated group had a higher complete remission (CR) rate (70.5% vs 54.7%, P = .003), a trend to a longer overall survival (OS; median 1012 vs 549 days, P = .076), and significantly longer event-free survival (EFS; median 428 vs 336 days; P = .012). The favorable impact of NPM1 mutations on OS and EFS clearly emerged in the large group (264 [66.8%] of 395 cases) of normal-karyotype AML without FLT3-LM. This positive effect was lost in the presence of a concomitant FLT3-LM, since survival of the NPM1+/FLT3-LM+ double positive was similar to NPM1–/FLT3-LM+ cases. In conclusion, this study demonstrates that NPM1+/FLT3-LM– mutations are an independent predictor for a favorable outcome in AML with normal karyotype.

The Residual Malignant Cells Could Be Masked by Therapeutic Use of Granulocyte-Colony Stimulating Factor in the Patients with AML1/ETO+ Acute Myelogenous Leukemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4512-4512
Author(s):  
Hee Won Moon ◽  
Ho Young Kim ◽  
Young Ree Kim ◽  
Han Ik Cho ◽  
Sung-Soo Yoon ◽  
...  
Keyword(s):  
Cell Line ◽  
Acute Myelogenous Leukemia ◽  
Normal Karyotype ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
P Value ◽  
Trisomy 8 ◽  
Morphological Examination ◽  
Suspected Infection ◽  
Acute Myelogenous

Abstract Among 200 AML cases for the past 7 years, we observed 6 cases with acute myelogenous leukemia(AML) which showed remission by morphologic criteria in BM examination, but revealed clonal changes in most cells by FISH after G-CSF administration. Remarkably, 5 of 6 cases were AML with AML1/ETO rearrangement, and FISH study revealed that most of AML1/ETO+ cells were mature neutrophils, suggesting differentiation of leukemic cells. A true remission of leukemia was probably never achieved with G-CSF alone and 4 of 6 cases have relapsed and 3 have died. Most cases of present study had infections or were suspected as infection, thus G-CSF which was administered and endogenously produced by infection seems to bring synergic effect (Table 1). To elucidate the mechanism involved in this finding, we measured the numbers of G-CSF receptor (G-CSFr) in AML1/ETO positive (Kasumi-1) and negative AML cell lines (CTV-1), and in leukemic cells from 8 patients with AML1/ETO positive and negative AML by flow cytometry. The number of G-CSFr was 2,673/cell in AML1/ETO+ Kasumi-1 cell line and 522/cell in AML1/ETO− CTV-1 cell line(Table 2). In 8 patients with AML, the number of baseline G-CSFr in AML1/ETO+ AML cells was significantly higher than that in AML1/ETO− AML cells (mean number 446.2 VS 226) (p value =0.0029). We assume that therapeutic G-CSF administration could result in differentiation and proliferation of AML1/ETO+ leukemic cells due to higher expression of G-CSF receptor. In conclusion, we strongly recommend that complete remission should be confirmed by FISH test, because malignant clone can be differentiated and masked in morphological examination or conventional cytogenetic test, especially for AML1/ETO+ AML. Table 1. Clinical and laboratory summary of cases Case No. Initial diagnosis Follow-up* Cytogenetics FISH % Blast in BM Cytogenetics FISH Other findings Outcomes * when showing discrepancy between morphologic examination and FISH test 1 t(8;21)(q22;q22) AML1/ETO: 94.5% 0%(PB) - AML1/ETO:95.5%(PB) Pneumonia Relapse 2 t(8;21)(q22;q22) AML1/ETO: 98% 39% - AML1/ETO:99% Suspected infection, G-CSF administration Relapse, death 3 t(8;21)(q22;q22) AML1/ETO: 47% 0.5% t(8;21)(q22;q22) AML1/ETO:55% Suspected infection, G-CSF administration Alive 4 t(8;21)(q22;q22) AML1/ETO: 94.5% 3.9% t(8;21)(q22;q22) AML1/ETO:77.5% Fever Relapse, death 5 t(8;21)(q22;q22) AML1/ETO: 93.5% 0.3% Normal karyotype AML1/ETO:33.5% G-CSF administration Relapse 6 Trisomy 8 Trisomy 8: 98.5% 28.1% Trisomy 8 Trisomy 8:96.5% Candidiasis, G-CSF administration Death Table 2. Quantitation of G-CSF receptors in Kasumi-1 and CTV-1 cell line G-CSF receptor (PE molecule per cell) Baseline After G-CSF administration Kasumi-1 cell line 2,673 1,953 CTV-1 cell line 522 556

Genome-Wide Analysis of Microdeletions and Identification of NF1 Inactivation in Acute Myelogenous Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 165-165
Author(s):  
Sami Malek ◽  
Peter Ouillette ◽  
Yin Wang ◽  
Yan Liu ◽  
Whitney Wright ◽  
...  
Keyword(s):  
Acute Myelogenous Leukemia ◽  
Copy Number ◽  
Research Funding ◽  
Normal Karyotype ◽  
B Cell Lymphoma ◽  
Myelogenous Leukemia ◽  
Acute Myelogenous ◽  
Copy Number Changes ◽  
Induced Apoptosis ◽  
High Level

Abstract Abstract 165 Genomic aberrations are of dominant importance to the biology and clinical outcome of patients with acute myelogenous leukemia (AML). To further our understanding of such aberrations in AML, we analyzed DNA from highly purified AML blasts and paired buccal cells from 95 patients for subchromosomal copy number changes and allele identities using ultra-high-density Affymetrix SNP 6.0 array-based genomic profiling. A total of 358 somatically acquired copy number changes were detected in 95 AML genomes. We detected 16 losses and 22 gains of entire chromosomes, 285 subchromosomal losses and 35 subchromosomal gains. No recurrent high-level amplifications or recurrent homozygous deletions were identified. Eight of the 34 AML cases (24%) with normal karyotype each had one lesion detected through 6.0 array profiling, all but one of which was less than 4Mb in length. Focusing on microdeletions as potential indicators of the locations of novel tumor suppressor genes or genes with importance to AML biology, we identified 60 deletions that were less than 1 Mb in length and 158 deletions of less than 5 Mb, the vast majority of which were undetectable by conventional cytogenetics. Through fine mapping of microdeletions on 17q, we identified Neurofibromin 1 (NF1) null states due to mutations or absent expression in ∼7% of AML. NF1 mutations were present in the hematopoetic stem cell compartment (CD34+/CD38- cell population) and siRNA-mediated NF1 suppression using recombinant lentiviruses significantly increased colony formation of primary AML blasts in methylcellulose. Further, AML blasts without functional NF1 displayed sensitivity to rapamycin-induced apoptosis, thus identifying a dependence on mTOR signaling for survival. As an additional validation of using microdeletions to guide pathogenetic gene discovery, we identified deletions involving RUNX1, IRF8, Core Binding Factor Beta (CBFB) and Casitas B-cell lymphoma B (CBLB), genes known to be altered in AML. IRF8 expression was found to be absent in ∼30% of all AML but sequencing of all coding exons of IRF8 of 48 AML cases did not disclose somatically acquired mutations. In summary, this comprehensive description of subchromosomal copy number changes and microdeletions in adult AML substantially adds to our knowledge of the pathological anatomy of the AML genome and should inform future searches for novel genes with importance to AML biology. Disclosures: Malek: Cephalon: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Affymetrix: Research Funding. Erba:Lilly: Research Funding; Antisoma: Research Funding; Wyeth: Research Funding; Cephalon: Honoraria, Research Funding; MGI Pharma: Honoraria; Pharmion: Honoraria; Celgene: Honoraria; BMS: Honoraria; Novartis: Honoraria, Research Funding; Genzyme: Consultancy, Honoraria, Research Funding; Gemin-X: Research Funding; Kanisa: Research Funding.

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