Endogenous Oncogenic Nras Mutation Initiates T-Cell Leukemia/Lymphoma In a Dose-Dependent Manner

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4183-4183
Author(s):  
Jinyong Wang ◽  
Zeyang Li ◽  
Zhongde Wang ◽  
Yangang Liu ◽  
Myung-Jeom Ryu ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
Lymphoblastic Leukemia ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Nras Mutation ◽  
Low Incidence ◽  
Dose Dependent ◽  
Notch1 Mutations

Abstract Abstract 4183 The oncogenic NRAS mutations are frequently identified in myeloid diseases but rare in lymphoid diseases. They occur in 4% of acute T-cell lymphoblastic leukemia/lymphoma (T-ALL) patients and 22% of human T-ALL cell lines. Its differential roles in myeloid versus lymphoid disease development remain unclear. Here we examine the tumorigenic potential of oncogenic Nras in T-cells using two conditional Nras G12D murine knock-in models that either hypomorphically (NrasG12D Hypo) or normally (NrasG12D Norm) expresses oncogenic Nras G12D from its endogenous locus. Mice expressing monoallelic or biallelic NrasG12D Hypo develop normally and are tumor free. However, NrasG12D Norm leads to acute T-cell leukemia/lymphoma (TAL/L) in a bone marrow transplantation model, with a low incidence (∼8%) when expressing one allele (TAL/L-het) and a complete penetrance when expressing two alleles (TAL/L-homo). TAL/L-het tumors are associated with spontaneous up-regulation of oncogenic Nras in ∼67% of animals, and tumor cells are TdT positive, suggesting that they are transformed at an immature stage. In contrast, TAL/L-homo tumors express comparable levels of Nras to control thymocytes, and tumor cells are TdT negative, suggesting that they are transformed at a more mature stage. Both TAL/L-het and TAL/L-homo tumors are oligoclonal or polyclonal. Above 70% of these tumors contain clonal Notch1 mutations and are sensitive to gamma-secretase inhibitor. These data indicate that Notch1 mutations are acquired at an early stage and play an important role in the development of TAL/L-het and TAL/L-homo tumors. Together, our results show that engdogenous oncogenic Nras mutation leads to TAL/L in a dose-dependent manner, and thus explain the low incidence of oncogenic NRAS mutations in human T-cell diseases. Disclosures: No relevant conflicts of interest to declare.

Depsipeptide (FK228) Preferntially Induces Apoptosis in Acute T-Cell Leukemia Cell Lines Mediated by CD45 and Src Kinase.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4468-4468
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Hal E. Broxmeyer ◽  
Kazuma Ohyashiki
Keyword(s):  
T Cell ◽  
Cell Line ◽  
Src Kinase ◽  
Jurkat Cells ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Histone H4 ◽  
Cell Leukemia ◽  
Histone H4 Acetylation ◽  
Dose Dependent

Abstract Histone acetyltransferases (HAT) and histone deacetylases (HDAC) control the acetylation of histones and intracellular proteins, and regulate the transcription and function of the proteins. One histone deacetylase inhibitor, depsipeptide (FK228) has shown clinical activity in a subset of resistant patients with T-cell lymphoma. However the mechanism of depsipeptide-induced apoptosis in acute T-cell leukemia cells has not yet been fully elucidated. To evaluate the mechanisms of action of depsipeptide, we utilized the acute T-cell leukemia cell line, Jurkat. Treatment with depsipeptide for 24h and 48h clearly reduced growth of Jurkat cells and increased apoptosis in a dose dependent manner. IC50 of depsipeptide was 0.75 ng/ml. Histone H4 was acetylated in time and dose dependent manner. Cells were blocked in G2/M phase of the cell cycle. Caspase 3, caspase 9, caspase 7 and poly (ADP-ribose) polymerase (PARP) were activated. Activity of mitogen-activated protein kinase (MAPK) and Akt was blocked after depsipeptide treatment. MAPK phosphatase-1 (Mkp-1) belongs to the protein tyrosine phosphatase family. Mkp-1 was induced after depsipeptide treatment in a time and dose dependent manner. Rb and Chk2 regulate cell cycle and phosphorylated by DNA damaged. We demonstrated that Rb (Ser 807/811, Ser 780 and Ser 795) and Chk2 (Thr 68, Ser 19 and Thr 432) were phosphorylated after depsipeptide treatment in a time and dose dependent manner. Rb, Chk2 were not involved in histone H4 acetylation directly after depsipeptide tratment in Jurkat cells by using siRNA of Rb and Chk2 transfection. Src-family protein tyrosine kinases are regulatory proteins of cell proliferation and survival. CD45 is abundantly expressed on all nucleated hematopoietic cells and regulates the activation of Src family kinases. We found that histone H4 acetylation was much more potentially induced in modified Jurkat T cell line, which had lost expression of full length of p56lck (lck), J.CaM1.6, and loss of expression of CD45 antigen, J45.01, compared to the parental cell line, Jurkat. Histone H4 acetylation was also enhanced pretreatment of src kinase inhibitor, PP2. Src binds to HSP-90, but association was decreased after depsipeptide treatment. Although CD45 is associated with Zap-70 and dissociates completely after depsipeptide treatment, one phosphatase, SHP-1, is increased in association with CD45. It is known that High Mobility Group Box chromosomal protein 1 (HMGB-1) is a nuclear DNA-binding protein and pRB associates with HDAC activity in vivo and binds to class I HDACs (HDAC1-HDAC3) in vitro. We found depsipeptide reduced the association of Rb with HDAC3 and HMGB-1. Jurkat cells respond chemotactically to Stromal Cell-Derived Factor-1α(SDF-1α/CXCL12). The chemotactic response to SDF-1α/CXCL12 was significantly decreased after depsipeptide treatment in a time dependent manner. Moreover, chemotactic inhibition of J45.01 cells was more sensitive to depsipeptide compared parental cell line, Jurkat. Depsipeptide potently induces apoptosis of an acute T-cell line, effects mediated by CD45 and Src kinase. Our study increases insight into how depsipeptide may mediate its effects on acute T-cell leukemia cells, information of potential therapeutic relevance.

scholarly journals Notch1 Contributes to Mouse T-Cell Leukemia by Directly Inducing the Expression of c-myc

2006 ◽  
Vol 26 (21) ◽  
pp. 8022-8031 ◽  
Author(s):  
Vishva Mitra Sharma ◽  
Jennifer A. Calvo ◽  
Kyle M. Draheim ◽  
Leslie A. Cunningham ◽  
Nicole Hermance ◽  
...  
Keyword(s):  
T Cell ◽  
Insertional Mutagenesis ◽  
Lymphoblastic Leukemia ◽  
Molecular Signature ◽  
Mrna Levels ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Genetic Event ◽  
Primary Mouse

ABSTRACT Recent work with mouse models and human leukemic samples has shown that gain-of-function mutation(s) in Notch1 is a common genetic event in T-cell acute lymphoblastic leukemia (T-ALL). The Notch1 receptor signals through a γ-secretase-dependent process that releases intracellular Notch1 from the membrane to the nucleus, where it forms part of a transcriptional activator complex. To identify Notch1 target genes in leukemia, we developed mouse T-cell leukemic lines that express intracellular Notch1 in a doxycycline-dependent manner. Using gene expression profiling and chromatin immunoprecipitation, we identified c-myc as a novel, direct, and critical Notch1 target gene in T-cell leukemia. c-myc mRNA levels are increased in primary mouse T-cell tumors that harbor Notch1 mutations, and Notch1 inhibition decreases c-myc mRNA levels and inhibits leukemic cell growth. Retroviral expression of c-myc, like intracellular Notch1, rescues the growth arrest and apoptosis associated with γ-secretase inhibitor treatment or Notch1 inhibition. Consistent with these findings, retroviral insertional mutagenesis screening of our T-cell leukemia mouse model revealed common insertions in either notch1 or c-myc genes. These studies define the Notch1 molecular signature in mouse T-ALL and importantly provide mechanistic insight as to how Notch1 contributes to human T-ALL.

Overexpression of hTLX3 in Association with Mutant IL7Rα Is Sufficient to Generate T-ALL In Vivo and to Transform Thymocytes in Vitro

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 21-21
Author(s):  
Gisele Olinto Libanio Rodrigues ◽  
Julie Hixon ◽  
Hila Winer ◽  
Erica Matich ◽  
Caroline Andrews ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Lymphoblastic Leukemia ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Counts

Mutations of the IL-7Rα chain occur in approximately 10% of pediatric T-cell acute lymphoblastic leukemia cases. While we have shown that mutant IL7Ra is sufficient to transform an immortalized thymocyte cell line, mutation of IL7Ra alone was insufficient to cause transformation of primary T cells, suggesting that additional genetic lesions may be present contributing to initiate leukemia. Studies addressing the combinations of mutant IL7Ra plus TLX3 overexpression indicates in vitro growth advantage, suggesting this gene as potential collaborative candidate. Furthermore, patients with mutated IL7R were more likely to have TLX3 or HOXA subgroup leukemia. We sought to determine whether combination of mutant hIL7Ra plus TLX3 overexpression is sufficient to generate T-cell leukemia in vivo. Double negative thymocytes were isolated from C57BL/6J mice and transduced with retroviral vectors containing mutant hIL7R plus hTLX3, or the genes alone. The combination mutant hIL7R wild type and hTLX3 was also tested. Transduced thymocytes were cultured on the OP9-DL4 bone marrow stromal cell line for 5-13 days and accessed for expression of transduced constructs and then injected into sublethally irradiated Rag-/- mice. Mice were euthanized at onset of clinical signs, and cells were immunophenotyped by flow cytometry. Thymocytes transduced with muthIL-7R-hTLX3 transformed to cytokine-independent growth and expanded over 30 days in the absence of all cytokines. Mice injected with muthIL7R-hTLX3 cells, but not the controls (wthIL7R-hTLX3or mutIL7R alone) developed leukemia approximately 3 weeks post injection, characterized by GFP expressing T-cells in blood, spleen, liver, lymph nodes and bone marrow. Furthermore, leukemic mice had increased white blood cell counts and presented with splenomegaly. Phenotypic analysis revealed a higher CD4-CD8- T cell population in the blood, bone marrow, liver and spleen compared in the mutant hIL7R + hTLX3 mice compared with mice injected with mutant IL7R alone indicating that the resulting leukemia from the combination mutant hIL7R plus hTLX3 shows early arrest in T-cell development. Taken together, these data show that oncogenic IL7R activation is sufficient for cooperation with hTLX3 in ex vivo thymocyte cell transformation, and that cells expressing the combination muthIL7R-hTLX3 is sufficient to trigger T-cell leukemia in vivo. Figure Disclosures No relevant conflicts of interest to declare.

scholarly journals Induction of the IL-9 gene by HTLV-I Tax stimulates the spontaneous proliferation of primary adult T-cell leukemia cells by a paracrine mechanism

Blood ◽  
2008 ◽  
Vol 111 (10) ◽  
pp. 5163-5172 ◽  
Author(s):  
Jing Chen ◽  
Mike Petrus ◽  
Bonita R. Bryant ◽  
Vinh Phuc Nguyen ◽  
Mindy Stamer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Proximal Promoter ◽  
Type I ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia ◽  
Spontaneous Proliferation

AbstractThe etiologic agent of adult T-cell leukemia (ATL) is human T cell lymphotropic virus type I (HTLV-I). The HTLV-I protein Tax alters gene expression, including those of cytokines and their receptors, which plays an important role in early stages of ATL. Here we demonstrate that expression of interleukin-9 (IL-9) is activated by Tax via an NF-κB motif in its proximal promoter, whereas IL-9 receptor-α (IL-9Rα) expression is not induced by Tax. However, supporting a role for IL-9/IL-9Rα in ATL, a neutralizing monoclonal antibody directed toward IL-9Rα inhibited ex vivo spontaneous proliferation of primary ATL cells from several patients. Fluorescence-activated cell sorter analysis of freshly isolated peripheral blood mononuclear cells from these patients revealed high level expression of IL-9Rα on their CD14-expressing monocytes. Furthermore, purified T cells or monocytes alone from these patients did not proliferate ex vivo, whereas mixtures of these cell types manifested significant proliferation through a contact-dependent manner. Taken together, our data suggest that primary ATL cells, via IL-9, support the action of IL-9Rα/CD14-expressing monocytes, which subsequently support the ex vivo spontaneous proliferation of malignant T cells. In summary, these data support a role for IL-9 and its receptor in ATL by a paracrine mechanism.

Interleukin-2 production by primary adult T cell leukemia tumor cells is macrophage dependent

1992 ◽  
Vol 41 (4) ◽  
pp. 258-263 ◽  
Author(s):  
Naomichi Arima ◽  
Yasuhisa Daitoku ◽  
Shiroh Hidakia ◽  
Kakushi Matsushita ◽  
Hideo Ohtsubo ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
Interleukin 2 ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia

Adult T-Cell Leukemia with Anti-HTLV-I Antibody but No HTLV-I DNA in Tumor Cells

2001 ◽  
Vol 105 (2) ◽  
pp. 103-105
Author(s):  
Hiroshi Fujiwara ◽  
Naomichi Arima ◽  
Tadashi Matsumoto ◽  
Hideo Ohtsubo ◽  
Kakushi Matsushita ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia

Adult T-cell leukemia-lymphoma unusual features of two patients from a low-incidence area

Cancer ◽  
1986 ◽  
Vol 58 (3) ◽  
pp. 694-698 ◽  
Author(s):  
Judith J. Temple ◽  
Melissa G. Brammer ◽  
W. Abe Andes ◽  
Steve Covington ◽  
Setular Rangan
Keyword(s):  
T Cell ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia ◽  
Low Incidence

scholarly journals Antitumor effects of chloroquine/hydroxychloroquine mediated by inhibition of the NF-κB signaling pathway through abrogation of autophagic p47 degradation in adult T-cell leukemia/lymphoma cells

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256320
Author(s):  
Yanuar Rahmat Fauzi ◽  
Shingo Nakahata ◽  
Syahrul Chilmi ◽  
Tomonaga Ichikawa ◽  
Phawut Nueangphuet ◽  
...  
Keyword(s):  
T Cell ◽  
Mouse Model ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Xenograft Mouse Model ◽  
Adult T Cell Leukemia ◽  
Atll Cell

Adult T-cell leukemia/lymphoma (ATLL) originates from human T-cell leukemia virus type 1 (HTLV-1) infection due to the activation of the nuclear factor-κB (NF-κB) signaling pathway to maintain proliferation and survival. An important mechanism of the activated NF-κB signaling pathway in ATLL is the activation of the macroautophagy (herafter referred to as autophagy in the remainder of this manuscript)-lysosomal degradation of p47 (NSFL1C), a negative regulator of the NF-κB pathway. Therefore, we considered the use of chloroquine (CQ) or hydroxychloroquine (HCQ) (CQ/HCQ) as an autophagy inhibitor to treat ATLL; these drugs were originally approved by the FDA as antimalarial drugs and have recently been used to treat autoimmune diseases, such as systemic lupus erythematosus (SLE). In this paper, we determined the therapeutic efficacy of CQ/HCQ, as NF-κB inhibitors, in ATLL mediated by blockade of p47 degradation. Administration of CQ/HCQ to ATLL cell lines and primary ATLL cells induced cell growth inhibition in a dose-dependent manner, and the majority of cells underwent apoptosis after CQ administration. As to the molecular mechanism, autophagy was inhibited in CQ-treated ATLL cells, and activation of the NF-κB pathway was suppressed with the restoration of the p47 level. When the antitumor effect of CQ/HCQ was examined using immunodeficient mice transplanted with ATLL cell lines, CQ/HCQ significantly suppressed tumor growth and improved the survival rate in the ATLL xenograft mouse model. Importantly, HCQ selectively induced ATLL cell death in the ATLL xenograft mouse model at the dose used to treat SLE. Taken together, our results suggest that the inhibition of autophagy by CQ/HCQ may become a novel and effective strategy for the treatment of ATLL.

scholarly journals Using HDAC Inhibitors to Eradicate Adult T-Cell Leukemia-Lymphoma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5492-5492
Author(s):  
Agustin Pimentel ◽  
Isildinha Reis ◽  
Ngoc Toomey ◽  
Luis Diaz ◽  
Phillip Ruiz ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cell ◽  
Pilot Trial ◽  
Hdac Inhibitors ◽  
Cytotoxic T Cell ◽  
Molecular Response ◽  
Dependent Manner ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Adult T Cell Leukemia

Abstract Adult T-cell leukemia-lymphoma (ATLL) is an aggressive malignancy with a poor prognosis caused by HTLV-I, which is endemic in Japan, the Caribbean, and South America. ATLL cannot be cured with conventional chemotherapy thus urging the development of new therapeutic strategies. Histone deacetyalse (HDAC) inhibitors are broadly active anti-neoplastic agents, which have shown efficacy in T-cell lymphomas. At our institution we encounter a relatively high number of ATLL cases as compared to other regions in the U.S. We have conducted a pilot trial using AZT/interferon-α(IFNα) plus the HDAC inhibitor valproic acid (VPA) during maintenance therapy in acute (leukemia-type) ATLL. We hypothesized that VPA would reactivate HTLV-I leading to a cytotoxic T-cell immune response followed by reduction of residual blood circulating ATLL clones that normally persist during AZT/IFNα therapy despite its suppressive effects. Supporting this notion, the addition of VPA to AZT/IFNα resulted in reduction of HTLV-I proviral loads in treated patients and a sustained molecular response in one subject who is still alive >4.5 years later. More recently, we have tested newly available and more potent HDAC inhibitors using fresh primary leukemic ATLL cells and low-passage cell lines. Through HDAC inhibition, these agents reactivated HTLV-I Tax gene expression and induced apoptosis in a dose-dependent manner. Belinostat, which is currently FDA-approved for the treatment of relapsed or refractory peripheral T-cell lymphoma, augmented ATLL cell death when added to AZT/IFNα at nanomolar concentrations. Therefore, we have proposed a new pilot clinical trial using belinostat for the treatment of ATLL during post-induction therapy. The role of HDAC inhibitors in ATLL, pre-clinical laboratory studies involving these agents, and clinical trial design will be discussed at the meeting Disclosures Off Label Use: The use of HDAC inhibitors in adult T-cell Leukemia-lymphoma.

scholarly journals Dnmt3a Haploisufficiency Cooperates with Oncogenic Kras to Promote an Early-Onset T-Cell Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2729-2729
Author(s):  
Yuan-I Chang ◽  
Guangyao Kong ◽  
Jing Zhang ◽  
Erik A. Ranheim
Keyword(s):  
T Cell ◽  
Dna Methyltransferase ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Myeloproliferative Neoplasm ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Myeloid Malignancies ◽  
Dose Dependent

Abstract Recent whole genome/exome sequencing efforts in myeloid malignancies identified that mutations in DNA methyltransferase 3A (DNMT3A) are prevalent in acute myeloid leukemia (AML). In addition, DNMT3A mutations are also identified in various T cell malignancies. Of note, DNMT3A mutations are typically heterozygous and some WT DNMT3A functions thus remain in this state. However, the predominant DNMT3A R882 mutations, which locate in the catalytic domain, seem to inhibit the methyltransferase activity of the remaining WT DNMT3A due to its dominant-negative function (Yang L, Rau R, Goodell MA, Nat. Rev. Cancer 15: 152-165, 2015). COSMIC database analysis reveals different prevalence of DNMT3A R882 mutations in various hematopoietic malignancies. Approximately 60% of DNMT3A mutations in AML are R882 mutations, while the frequency of R882 mutations drops to ~40% in myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). In contrast, the frequency of R882mutations is less than 25% in T-cell acute lymphoblastic leukemia (T-ALL). The significantly different frequencies of DNMT3A R882 mutations in AML versus T-ALL inspired us to investigate whether downregulation of DNMT3A regulates malignancies of different lineages in a dose-dependent manner. We previously showed that Dnmt3a-/- promotes MPN progression in KrasG12D/+ mice and ~1/3 compound mice develop AML-like disease (Chang et al. Leukemia 29: 1847-1856, 2015). Here, we generated KrasG12D/+; Dnmt3afl/+; Mx1-Cre mice to determine how Dnmt3a haploisufficiency affects KrasG12D/+-induced leukemogenesis. After pI-pC injections to induce Mx1-Cre expression, primary KrasG12D/+; Dnmt3a+/- mice died quickly as primary KrasG12D/+ mice; the survival rates of these two groups of animals were not significantly different. However, in a competitive transplant setting, recipients transplanted with KrasG12D/+; Dnmt3a+/- bone marrow cells displayed a significantly shortened survival than recipients with KrasG12D/+ cells. Moreover, all of the recipients with KrasG12D/+; Dnmt3a+/- cells developed a lethal T-ALL without significant MPN phenotypes, while ~20% of recipients with KrasG12D/+ cells developed MPN with or without T-ALL. This is in sharp contrast to the recipients with KrasG12D/+; Dnmt3a-/- cells, in which ~60% developed a lethal myeloid malignancy (MPN or AML). Our data suggest that in the context of oncogenic Kras, loss of Dnmt3a promotes myeloid malignancies, while Dnmt3a haploisufficiency induces T-ALL. This dose-dependent phenotype is highly consistent with the prevalence of DNMT3A R882 mutations in AML versus T-ALL in human. We are currently investigating the underlying mechanisms. Disclosures No relevant conflicts of interest to declare.

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