Genetic Dissection of Cooperating Mutations in BXH-2 Acute Myeloid Leukemia with and without Nf1 Gene Mutation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2567-2567
Author(s):  
Bin Yin ◽  
Jessica Walrath ◽  
Kevin M. Shannon ◽  
Margaret R. Wallace ◽  
David A. Largaespada
Keyword(s):  
Acute Myeloid Leukemia ◽  
National Cancer Institute ◽  
Myeloid Leukemia ◽  
Genetic Alterations ◽  
Expression Vectors ◽  
Juvenile Myelomonocytic Leukemia ◽  
Wild Type ◽  
Monosomy 7 ◽  
Nf1 Gene ◽  
Acute Myeloid

Abstract Loss of the NF1 (Neurofibromatosis Type 1) gene, a tumor suppressor, can cause myeloid diseases juvenile myelomonocytic leukemia (JMML), monosomy 7 syndrome (Mo7), and acute myeloid leukemia (AML). However, using knockout mice, it has been shown that loss of Nf1 expression in hematopoietic cells, by itself, does not lead to aggressive leukemia resulting instead in a relatively indolent myeloproliferative disease. Murine Leukemia Virus (MuLV) insertional mutagenesis in BXH-2 mice provides a model to dissect genetic alterations in AML. We have profiled proviral insertions in BXH-2 AML which do or do not have corresponding loss-of-function of Nf1. 197 PIS (68 from 25 Nf1-wild type AML and 129 from 55 Nf1-defective AML) were isolated. Nf1-defective AML were obtained from BXH-2 AMLs with proviral insertions into the endogenous Nf1 gene and AML that developed in leukemia-prone, heterozygous Nf1+/− BXH-2 mice. These latter AMLs develop faster than wild-type BXH-2 AMLs and show Nf1 gene LOH or proviral insertion into the wild-type Nf1 allele. These analyses led to 37 common proviral insertion sites (CIS), 13 of which have not been reported previously. Several of the CIS (including Lmo2, Cmyb, Meis1, Bcl11a, Spred2, Def8, Edg3, Hoxa9, and a novel Krab domain-zinc finger gene) were found repeatedly among the Nf1-defective group of AML. Expression of most could be detected in human JMML and CMML by RT-PCR, including BCL11A. Importantly, among the CIS we detected, PIS targeting Bcl11a were significantly enriched (p < 0.05) in Nf1-defective leukemia. Retroviral expression vectors for Bcl11a have been constructed and transduced into an immortalized Nf1-/- null myeloblast cell line. Growth assays show that the cumulative cell number of FACS-sorted Bcl11a-Nf1-/- cells increase by ~2.5 fold that of controls. BXH-2 provides a powerful genetic system to dissect Nf1-cooperating genetic events in tumorigenesis. Mutations at several novel common integration sites could be involved in development or progression of leukemia with NF1 gene inactivation. This work was supported by the National Cancer Institute (U01-CA84221-05) and the American Cancer Society (RPG LIB-106632) to DAL and by National Cancer Institute (R01 CA92095) and U.S. Dept. of Defense (DAMD17-97-1-7339) to MRW.

scholarly journals Retroviral Integration at the Epi1Locus Cooperates with Nf1 Gene Loss in the Progression to Acute Myeloid Leukemia

2001 ◽  
Vol 75 (19) ◽  
pp. 9427-9434 ◽  
Author(s):  
Susan M. Blaydes ◽  
Scott C. Kogan ◽  
Bao-Tran H. Truong ◽  
Debra J. Gilbert ◽  
Nancy A. Jenkins ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Neurofibromatosis Type ◽  
Juvenile Myelomonocytic Leukemia ◽  
Loss Of Function ◽  
Hematopoietic Stem ◽  
Retroviral Integration ◽  
Increased Risk ◽  
Nf1 Gene ◽  
Acute Myeloid

ABSTRACT Juvenile myelomonocytic leukemia (JMML) is a disease that occurs in young children and is associated with a high mortality rate. In most patients, JMML has a progressive course leading to death by virtue of infection, bleeding, or progression to acute myeloid leukemia (AML). As it is known that children with neurofibromatosis type 1 syndrome have a markedly increased risk of developing JMML, we have previously developed a mouse model of JMML through reconstitution of lethally irradiated mice with hematopoietic stem cells homozygous for a loss-of-function mutation in the Nf1 gene (D. L. Largaespada, C. I. Brannan, N. A. Jenkins, and N. G. Copeland, Nat. Genet. 12:137–143, 1996). In the course of these experiments, we found that all these genetically identical reconstituted mice developed a JMML-like disorder, but only a subset went on to develop more acute disease. This result strongly suggests that additional genetic lesions are responsible for disease progression to AML. Here, we describe the production of a unique tumor panel, created using the BXH-2 genetic background, for identification of these additional genetic lesions. Using this tumor panel, we have identified a locus, Epi1, which maps 30 to 40 kb downstream of theMyb gene and appears to be the most common site of somatic viral integration in BXH-2 mice. Our findings suggest that proviral integrations at Epi1 cooperate with loss of Nf1to cause AML.

hnRNP K Overexpression Synergizes with Mutant NPM1 to Drive Acute Myeloid Leukemia Progression

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2382-2382 ◽  
Author(s):  
Miguel Gallardo ◽  
Hun Ju Lee ◽  
Xiaorui Zhang ◽  
Laura R. Pageon ◽  
Asha Multani ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Conflicts Of Interest ◽  
Genetic Alterations ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Hnrnp K ◽  
Differentiation And Proliferation ◽  
Acute Myeloid ◽  
Proliferation Potential

Abstract NPM1 mutations are one of the most common alterations observed in acute myeloid leukemia (AML). When coupled with wild type FLT3 status in cytogenetically normal (CN) patients, NPM1 mutations confer favorable prognoses compared with other alterations. However, a subset of CN NPM1Mut :FLT3Wt patients with AML have dismal outcomes, suggesting that uncharacterized alterations influence the outcomes in these patients. To address this, we performed reverse phase protein array (RPPA) analysis on CD34+ bone marrow cells isolated from 43 de novo CN NPM1Mut :FLT3Wt AML patient as well as healthy donor controls. Through these analyses, we observed that overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K) associated with extremely poor outcomes within this a priori favorable prognostic group, as almost 90% of patients with increased hnRNP K expression died within 12 months of diagnosis while nearly 40% of individuals with normal hnRNP K expression survived seven years (Figure 1A). hnRNP K is a multifunctional RNA and DNA binding protein whose expression is often altered in cancers. To directly examine the functional relationship between hnRNP K overexpression and mutant NPM1 in hematologic malignancies, we generated tissue-specific transgenic mouse models with the ability to overexpress hnRNP K (hnRNP KTg) in the presence or absence of mutant Npm1 (Npm1Tg). By crossing these mice with Vav-Cre expressing mice, we specifically activated hnRNP K overexpression and mutant NPM1 expression in the hematological compartment. Using Lin-CD117+ hematopoietic stem cells (HSCs) from hnRNP KTg, Npm1Tg, and hnRNP KTg;Npm1Tg mice, we observed significant changes in differentiation and proliferation potential in colony formation assays. Overexpression of hnRNP K alone significantly increased the number of colonies compared to wild type and Npm1Tg HSCs while expression of mutant Npm1Tg resulted in increased numbers of cells compared to wild type and hnRNP KTg HSCs. Importantly, the combination of hnRNP K overexpression and mutant Npm1 resulted in a cumulative increase in both the number of colonies and number of cells, indicating that hnRNP K and mutant NPM1 cooperate to dictate differentiation and proliferation potential in HSCs (Figure 1B). Next, we examined the in vivo impact of hnRNP K overexpression and mutant Npm1 expression by analyzing the bone marrows of Npm Tg, hnRNP KTg, and Npm1Tg;hnRNP KTg mice. Within the first six months of life, these mice rapidly developed significant myeloid hyperplasias as determined by flow cytometry and pathologic analyses (Figure 1C). Together, our findings reveal that mutant Npm1 and hnRNP K overexpression result in similar myeloid phenotypes. However, these genetic alterations are also cooperative, suggesting both increased hnRNP K expression and mutant NPM1 synergize to impact hematopoietic phenotypes and drive AML progression through similar pathways but potentially via unique molecular processes. Currently, we are investigating the direct interaction and global relationship between hnRNP K and mutant Npm1 in regulating tumor suppressor and oncogenic programs (e.g.; p53- and c-Myc pathways). Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals Juvenile Myelomonocytic Leukemia (JMML): A Mimicker of KMT2A-Rearranged Acute Myeloid Leukemia (AML)

2020 ◽  
Author(s):  
Ashraf Abdullah Saad
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Hematologic Malignancies ◽  
Driver Mutations ◽  
Juvenile Myelomonocytic Leukemia ◽  
Monosomy 7 ◽  
Acute Myelomonocytic Leukemia ◽  
Myelomonocytic Leukemia ◽  
Acute Myeloid

Juvenile myelomonocytic leukemia (JMML) is the most confusing mimicker of KMT2A-rearranged acute myeloid leukemia (AML). Clinical presentation, age of susceptibility (infancy or early childhood) and abnormal monocytosis are common clinical features. To complicate matters, JMML morphologically resemble acute myelomonocytic leukemia (AML M4) and distinction must be made based on accurate blast and promonocyte counts. As treatment significantly varies, AML/JMML overlap can lead to catastrophic consequences that can be avoided by timely management. Therefore, meticulous knowledge of JMML is essential to treat patients with hematologic malignancies. The pathognomic feature of JMML is increased infiltration of the peripheral blood, bone marrow, and viscera by abnormal myelomonocytic cells. Molecular diagnostics has generated substantial dividends in dissecting the genetic basis of JMML. We can now molecularly confirm the diagnosis of JMML in approximately over 90% of patients who harbor driver mutations in KRAS, NRAS, PTPN11, NF1, or CBL genes. The presence of monosomy 7 is a classic feature of JMML that can support the diagnosis in many cases. On the other hand, cytogenetics and Fluorescence in situ hybridization analysis (FISH) are indispensable to differentiate KMT2A-rearranged AML from JMML. In particular, AML with t(9;11) is associated with monocytic features that can be easily mistaken for JMML.

hnRNP K: A Novel Regulator of Hematopoiesis and A Potential Predictive Biomarker In Acute Myeloid Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 226-226 ◽  
Author(s):  
Miguel Gallardo ◽  
Hun Ju Lee ◽  
Xiaorui Zhang ◽  
Aziz Nazha ◽  
Laura R. Pageon ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Mouse Models ◽  
Myeloid Leukemia ◽  
Genetic Alterations ◽  
Wild Type ◽  
Self Renewal ◽  
Hnrnp K ◽  
Lethal Phenotype ◽  
Acute Myeloid

Abstract In acute myeloid leukemia (AML), numerous genetic and epigenetic changes have been identified that result in loss of differentiation, apoptosis, and cell cycle arrest. In contrast, changes in protein expression are not as well characterized. To address these deficiencies, we performed RPPA analysis on 415 de novo AML patient samples and identified increased expression of heterogeneous nuclear ribonucleoprotein K (hnRNP K) as a predictor of poor outcome. These elevated hnRNP K levels were most predictive in AML patients who also harbored mutant NPM1 and wild type FLT3. While NPM1MUT/FLT3WT status typically confers favorable prognoses, increased hnRNP K expression negated this effect, as greater than 90% of NPM1MUT/FLT3WTindividuals with elevated hnRNP K expression died within 12 months. hnRNP K is a multifunctional protein that controls basic cellular functions through RNA, DNA, and protein-protein interactions (e.g.; p53) and whose expression is often altered in cancer. To examine the biological role of hnRNP K in vivo, we generated mouse models that either increase or decrease hnRNP K expression. Biallelic hnRNP K deletion results in embryonic lethality, while haploinsufficiency (hnRNP K+/-) results in a partial neonatal lethal phenotype. Surviving hnRNP K+/- mice have reduced survival and are more tumor prone than wild type mice (Fig. 1A and B). Analysis of hnRNP K+/- peripheral blood and bone marrow revealed significant hematologic neoplasms, including myeloid hyperplasias. The myeloid expansion appears to be a consequence of defects in proliferation (decreased p21) and differentiation (increased C/EBPβ and ε expression and activation of Stat3) pathways (Fig. 1C). In vitro studies using hnRNP K+/- hematopoietic stem cells (HSC) and mouse embryo fibroblast (MEFs) likewise revealed defects in differentiation and proliferation potential. HSC were used in burst formation unit erythroid colony assays (BFU-E). In these experiments, we observed a significant increase in the number of hnRNP K+/- cells and immature cells as compared to wild type BFU-E (Fig. 2A and B). RT-PCR analysis of BFU-Es revealed deregulation of p53/p21 and TGFβ- pathway genes (Fig. 2C). Similarly, hnRNP K+/- MEFs failed to properly activate the p53/p21 pathway following exposure to ionizing radiation (Fig. 2D). In contrast to diminished hnRNP K expression, overexpression results in activation of pro-growth and self-renewal pathway proteins in both humans and mice. RPPA analysis of AML patient samples that overexpress hnRNP K, as well as transient overexpression of hnRNP K in cell lines, results in increased expression of c-Myc. To directly examine the impact of hnRNP K overexpression in vivo, we generated transgenic mouse models. hnRNPK-transgenic mice express elevated levels of hnRNP K and are tumor prone. While it is tempting to classify hnRNP K as either an oncogene or a tumor suppressor, our haploinsufficiency and overexpression data seem to indicate that abnormal expression in either direction has a significant impact on tumor predisposition. Mechanistically, hnRNP Kappears to be an influential regulator involved in proliferation, self-renewal, and differential programs. The functional consequences reduced and overexpression of hnRNP K is currently under investigation. Given the clinical relationship between hnRNP K expression and NPM1 status, it is our next priority to evaluate the synergistic relationship between hnRNPK and NPM1 in regulating hematopoiesis and AML progression. To this end, we have taken two approaches. The first is to identify the biological relationship between these two proteins. To do this, we are attempting to generate double heterozygous NPM1+/- and hnRNP K+/- mice. However, thus far, double haploinsufficiency (NPM1+/-hnRNP K+/-) appears to result in a synthetic lethal phenotype. This surprising result highlights the unique in vivo relationship between these proteins. In the second approach, we have generated hnRNP K-transgenic (hnRNP KTG) mice on a mutant NPM1 (NPM1Mut) background. This hnRNPKTG: NPM1Mut mouse model specifically recapitulates the genetic alterations observed in the AML human patients who have reduction in survival. Together, these models will allow us to determine the relationship between these two proteins and examine how they impact leukemogenesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Altered Spatial Composition of the Immune Cell Repertoire in Association to CD34+ Blasts in Myelodysplastic Syndromes and Secondary Acute Myeloid Leukemia

Cancers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 186
Author(s):  
Marcus Bauer ◽  
Christoforos Vaxevanis ◽  
Haifa Kathrin Al-Ali ◽  
Nadja Jaekel ◽  
Christin Le Hoa Naumann ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndromes ◽  
Myeloid Leukemia ◽  
Multispectral Imaging ◽  
Immune Cell ◽  
Genetic Alterations ◽  
Spatial Proximity ◽  
Secondary Acute Myeloid Leukemia ◽  
Acute Myeloid

Background: Myelodysplastic syndromes (MDS) are caused by a stem cell failure and often include a dysfunction of the immune system. However, the relationship between spatial immune cell distribution within the bone marrow (BM), in relation to genetic features and the course of disease has not been analyzed in detail. Methods: Histotopography of immune cell subpopulations and their spatial distribution to CD34+ hematopoietic cells was determined by multispectral imaging (MSI) in 147 BM biopsies (BMB) from patients with MDS, secondary acute myeloid leukemia (sAML), and controls. Results: In MDS and sAML samples, a high inter-tumoral immune cell heterogeneity in spatial proximity to CD34+ blasts was found that was independent of genetic alterations, but correlated to blast counts. In controls, no CD8+ and FOXP3+ T cells and only single MUM1p+ B/plasma cells were detected in an area of ≤10 μm to CD34+ HSPC. Conclusions: CD8+ and FOXP3+ T cells are regularly seen in the 10 μm area around CD34+ blasts in MDS/sAML regardless of the course of the disease but lack in the surrounding of CD34+ HSPC in control samples. In addition, the frequencies of immune cell subsets in MDS and sAML BMB differ when compared to control BMB providing novel insights in immune deregulation.

Genetic alterations and their clinical implications in older patients with acute myeloid leukemia

Leukemia ◽  
2016 ◽  
Vol 30 (7) ◽  
pp. 1485-1492 ◽  
Author(s):  
C-H Tsai ◽  
H-A Hou ◽  
J-L Tang ◽  
C-Y Liu ◽  
C-C Lin ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Older Patients ◽  
Myeloid Leukemia ◽  
Genetic Alterations ◽  
Clinical Implications ◽  
Acute Myeloid

scholarly journals Phase I/II Study of Combination Therapy With Sorafenib, Idarubicin, and Cytarabine in Younger Patients With Acute Myeloid Leukemia

2010 ◽  
Vol 28 (11) ◽  
pp. 1856-1862 ◽  
Author(s):  
Farhad Ravandi ◽  
Jorge E. Cortes ◽  
Daniel Jones ◽  
Stefan Faderl ◽  
Guillermo Garcia-Manero ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Complete Remission ◽  
Phase I ◽  
Myeloid Leukemia ◽  
Wild Type ◽  
Platelet Recovery ◽  
Probability Of Survival ◽  
Target Effect ◽  
Acute Myeloid

Purpose To determine the efficacy and toxicity of the combination of sorafenib, cytarabine, and idarubicin in patients with acute myeloid leukemia (AML) younger than age 65 years. Patients and Methods In the phase I part of the study, 10 patients with relapsed AML were treated with escalating doses of sorafenib with chemotherapy to establish the feasibility of the combination. We then treated 51 patients (median age, 53 years; range, 18 to 65 years) who had previously untreated AML with cytarabine at 1.5 g/m2 by continuous intravenous (IV) infusion daily for 4 days (3 days if > 60 years of age), idarubicin at 12 mg/m2 IV daily for 3 days, and sorafenib at 400 mg orally twice daily for 7 days. Results Overall, 38 (75%) patients have achieved a complete remission (CR), including 14 (93%) of 15 patients with mutated FMS-like tyrosine kinase-3 (FLT3; the 15th patient had complete remission with incomplete platelet recovery [CRp]) and 24 (66%) of 36 patients with FLT3 wild-type (WT) disease (three additional FLT3-WT patients had CRp). FLT3-mutated patients were more likely to achieve a CR than FLT3-WT patients (P = .033). With a median follow-up of 54 weeks (range, 8 to 87 weeks), the probability of survival at 1 year is 74%. Among the FLT3-mutated patients, 10 have relapsed and five remain in CR with a median follow-up of 62 weeks (range, 10 to 76 weeks). Plasma inhibitory assay demonstrated an on-target effect on FLT3 kinase activity. Conclusion Sorafenib can be safely combined with chemotherapy, produces a high CR rate in FLT3-mutated patients, and inhibits FLT3 signaling.

scholarly journals Co-occurrence of immature T-lymphoblastic lymphoma and acute myeloid leukemia—microenvironment-dependent lineage differentiation derived from a common progenitor?

2021 ◽  
Author(s):  
Edit Porpaczy ◽  
Wolfgang R. Sperr ◽  
Renate Thalhammer ◽  
Gerlinde Mitterbauer-Hohendanner ◽  
Leonhard Müllauer ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Next Generation Sequencing ◽  
Myeloid Leukemia ◽  
Genetic Alterations ◽  
Lymphoblastic Lymphoma ◽  
Simultaneous Occurrence ◽  
Next Generation ◽  
T Lymphoblastic Lymphoma ◽  
Generation Sequencing ◽  
Acute Myeloid

AbstractMixed phenotype acute leukemia (MPAL) is an uncommon disease characterized by currently only limited knowledge concerning biology, clinical presentation, and treatment outcome. We here describe a most unusual case of simultaneous occurrence of T-lymphoblastic lymphoma in cervical and mediastinal lymph nodes and acute myeloid leukemia in the bone marrow (BM) successfully treated with allogeneic stem cell transplantation (SCT). Although the blasts in both locations showed additional aberrant expression of other lineage markers (even B-cell markers), diagnostic criteria of MPAL were not fulfilled either in the LN or in the BM. We performed next generation sequencing (NGS) with the objective to look for common genetic aberrations in both tissues. Histology, immunohistochemistry, flow cytometry, AML-associated genetic alterations (FLT3, NPM1, KIT D816V, CEPBA), and clonal T-cell receptor β and γ gene rearrangements were performed according to routine diagnostic workflows. Next generation sequencing and Sanger sequencing were additionally performed in BM and LN. Somatic mutation in the EZH2 gene (p.(Arg684Cys)) was detected in the BM by NGS, and the same mutation was found in the LN. Since an identical genetic aberration (EZH2 mutation) was detected in both locations, a common progenitor with regional dependent differentiation may be involved.

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