1
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Vincelette ND, Yu X, Kuykendall AT, Moon J, Su S, Cheng CH, Sammut R, Razabdouski TN, Nguyen HV, Eksioglu EA, Chan O, Al Ali N, Patel PC, Lee DH, Nakanishi S, Ferreira RB, Hyjek E, Mo Q, Cory S, Lawrence HR, Zhang L, Murphy DJ, Komrokji RS, Lee D, Kaufmann SH, Cleveland JL, Yun S. Trisomy 8 Defines a Distinct Subtype of Myeloproliferative Neoplasms Driven by the MYC-Alarmin Axis. Blood Cancer Discov 2024; 5:276-297. [PMID: 38713018 PMCID: PMC11215389 DOI: 10.1158/2643-3230.bcd-23-0210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 03/16/2024] [Accepted: 05/06/2024] [Indexed: 05/08/2024] Open
Abstract
Despite advances in understanding the genetic abnormalities in myeloproliferative neoplasms (MPN) and the development of JAK2 inhibitors, there is an urgent need to devise new treatment strategies, particularly for patients with triple-negative (TN) myelofibrosis (MF) who lack mutations in the JAK2 kinase pathway and have very poor clinical outcomes. Here we report that MYC copy number gain and increased MYC expression frequently occur in TN-MF and that MYC-directed activation of S100A9, an alarmin protein that plays pivotal roles in inflammation and innate immunity, is necessary and sufficient to drive development and progression of MF. Notably, the MYC-S100A9 circuit provokes a complex network of inflammatory signaling that involves numerous hematopoietic cell types in the bone marrow microenvironment. Accordingly, genetic ablation of S100A9 or treatment with small molecules targeting the MYC-S100A9 pathway effectively ameliorates MF phenotypes, highlighting the MYC-alarmin axis as a novel therapeutic vulnerability for this subgroup of MPNs. Significance: This study establishes that MYC expression is increased in TN-MPNs via trisomy 8, that a MYC-S100A9 circuit manifest in these cases is sufficient to provoke myelofibrosis and inflammation in diverse hematopoietic cell types in the BM niche, and that the MYC-S100A9 circuit is targetable in TN-MPNs.
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Affiliation(s)
- Nicole D. Vincelette
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Xiaoqing Yu
- Department of Biostatistics and Bioinformatics, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Andrew T. Kuykendall
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Jungwon Moon
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Siyuan Su
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois.
| | - Chia-Ho Cheng
- Department of Biostatistics and Bioinformatics, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Rinzine Sammut
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
- Département d’Hématologie Clinique, Centre Hospitalier Universitaire de Nice, Nice, France.
| | - Tiffany N. Razabdouski
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Hai V. Nguyen
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.
| | - Erika A. Eksioglu
- Department of Immunology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Onyee Chan
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Najla Al Ali
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Parth C. Patel
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
- Department of Internal Medicine, University of South Florida, Tampa, Florida.
| | - Dae H. Lee
- Division of Cardiovascular Science, Department of Internal Medicine, University of South Florida, Tampa, Florida
| | - Shima Nakanishi
- Department of Tumor Microenvironment & Metastasis, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Renan B. Ferreira
- Department of Drug Discovery, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Elizabeth Hyjek
- Department of Pathology and Laboratory Medicine, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Qianxing Mo
- Department of Biostatistics and Bioinformatics, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Suzanne Cory
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.
| | - Harshani R. Lawrence
- Department of Drug Discovery, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Ling Zhang
- Department of Pathology and Laboratory Medicine, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Daniel J. Murphy
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
- Cancer Research UK Scotland Institute, Glasgow, United Kingdom.
| | - Rami S. Komrokji
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Daesung Lee
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois.
| | - Scott H. Kaufmann
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.
- Department of Oncology, Mayo Clinic, Rochester, Minnesota.
| | - John L. Cleveland
- Department of Tumor Microenvironment & Metastasis, Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Seongseok Yun
- Department of Malignant Hematology, Moffitt Cancer Center & Research Institute, Tampa, Florida.
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2
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Yang J, Chung CI, Koach J, Liu H, Navalkar A, He H, Ma Z, Zhao Q, Yang X, He L, Mittag T, Shen Y, Weiss WA, Shu X. MYC phase separation selectively modulates the transcriptome. Nat Struct Mol Biol 2024:10.1038/s41594-024-01322-6. [PMID: 38811792 DOI: 10.1038/s41594-024-01322-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/22/2024] [Indexed: 05/31/2024]
Abstract
Dysregulation and enhanced expression of MYC transcription factors (TFs) including MYC and MYCN contribute to the majority of human cancers. For example, MYCN is amplified up to several hundredfold in high-risk neuroblastoma. The resulting overexpression of N-myc aberrantly activates genes that are not activated at low N-myc levels and drives cell proliferation. Whether increasing N-myc levels simply mediates binding to lower-affinity binding sites in the genome or fundamentally changes the activation process remains unclear. One such activation mechanism that could become important above threshold levels of N-myc is the formation of aberrant transcriptional condensates through phase separation. Phase separation has recently been linked to transcriptional regulation, but the extent to which it contributes to gene activation remains an open question. Here we characterized the phase behavior of N-myc and showed that it can form dynamic condensates that have transcriptional hallmarks. We tested the role of phase separation in N-myc-regulated transcription by using a chemogenetic tool that allowed us to compare non-phase-separated and phase-separated conditions at equivalent N-myc levels, both of which showed a strong impact on gene expression compared to no N-myc expression. Interestingly, we discovered that only a small percentage (<3%) of N-myc-regulated genes is further modulated by phase separation but that these events include the activation of key oncogenes and the repression of tumor suppressors. Indeed, phase separation increases cell proliferation, corroborating the biological effects of the transcriptional changes. However, our results also show that >97% of N-myc-regulated genes are not affected by N-myc phase separation, demonstrating that soluble complexes of TFs with the transcriptional machinery are sufficient to activate transcription.
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Affiliation(s)
- Junjiao Yang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Chan-I Chung
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Jessica Koach
- Departments of Neurology, Neurological Surgery, Pediatrics, and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Hongjiang Liu
- Institute for Human Genetics, Departments of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Ambuja Navalkar
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Hao He
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Zhimin Ma
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Qian Zhao
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Xiaoyu Yang
- Institute for Human Genetics, Departments of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Liang He
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Yin Shen
- Institute for Human Genetics, Departments of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - William A Weiss
- Departments of Neurology, Neurological Surgery, Pediatrics, and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Xiaokun Shu
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA.
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Helen Diller Family Comprehensive Center, University of California, San Francisco, San Francisco, CA, USA.
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3
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Freie B, Carroll PA, Varnum-Finney BJ, Ramsey EL, Ramani V, Bernstein I, Eisenman RN. A germline point mutation in the MYC-FBW7 phosphodegron initiates hematopoietic malignancies. Genes Dev 2024; 38:253-272. [PMID: 38565249 PMCID: PMC11065175 DOI: 10.1101/gad.351292.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/19/2024] [Indexed: 04/04/2024]
Abstract
Oncogenic activation of MYC in cancers predominantly involves increased transcription rather than coding region mutations. However, MYC-dependent lymphomas frequently acquire point mutations in the MYC phosphodegron, including at threonine 58 (T58), where phosphorylation permits binding via the FBW7 ubiquitin ligase triggering MYC degradation. To understand how T58 phosphorylation functions in normal cell physiology, we introduced an alanine mutation at T58 (T58A) into the endogenous c-Myc locus in the mouse germline. While MYC-T58A mice develop normally, lymphomas and myeloid leukemias emerge in ∼60% of adult homozygous T58A mice. We found that primitive hematopoietic progenitor cells from MYC-T58A mice exhibit aberrant self-renewal normally associated with hematopoietic stem cells (HSCs) and up-regulate a subset of MYC target genes important in maintaining stem/progenitor cell balance. In lymphocytes, genomic occupancy by MYC-T58A was increased at all promoters compared with WT MYC, while genes differentially expressed in a T58A-dependent manner were significantly more proximal to MYC-bound enhancers. MYC-T58A lymphocyte progenitors exhibited metabolic alterations and decreased activation of inflammatory and apoptotic pathways. Our data demonstrate that a single point mutation stabilizing MYC is sufficient to skew target gene expression, producing a profound gain of function in multipotential hematopoietic progenitors associated with self-renewal and initiation of lymphomas and leukemias.
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Affiliation(s)
- Brian Freie
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA;
| | - Patrick A Carroll
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
| | | | - Erin L Ramsey
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
| | - Vijay Ramani
- Gladstone Institute for Data Science and Biotechnology, University of California, San Francisco, San Francisco, California 94158, USA
| | - Irwin Bernstein
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
| | - Robert N Eisenman
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA;
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Zhang X, Wang T, Zhang Y, Wang F, Chen J, Ni J, Sun R, Wei Z, Zhang G, Li W, Li J, Lu P. Characteristics and therapeutic approaches for patients diagnosed with T-ALL/LBL exhibiting t(8;14)(q24;q11)/TCRA/D:MYC translocation. Leuk Lymphoma 2023; 64:2133-2139. [PMID: 37674391 DOI: 10.1080/10428194.2023.2254428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 09/08/2023]
Abstract
T-acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) patients with t(8;14)(q24;q11)/TCRA/D::MYC translocation represent a rare subgroup, with an aggressive course. In our retrospective analysis of 14 patients, all were identified during refractory or relapsed stages (5 primary tumor, 9 relapse). Notably, extramedullary invasion was detected in most patients. Four exhibited STIL::TAL1 translocation, and six demonstrated CDKN2A/B gene loss. The therapeutic outcomes were notably poor for all seven patients who received only chemotherapy or allogeneic hematopoietic stem cell transplantation (HSCT); all eventually succumbed to the disease with a median OS of 3 months. In the application of CD7 CAR-T therapy in six patients, five achieved CR. Of the four patients who underwent HSCT following CAR-T therapy, all have remained disease-free. The prognosis for T-ALL/LBL patients with t(8;14) translocation remains bleak, but interventions involving CD7 CAR-T may offer a potential pathway to CR. HSCT following CAR-T could be a viable strategy for long-term survival.
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Affiliation(s)
- Xian Zhang
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
| | - Tong Wang
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
| | - Yang Zhang
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Fang Wang
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Jiaqi Chen
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Jingbo Ni
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Ruijuan Sun
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
| | - Zhijie Wei
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
| | - Gailing Zhang
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Wenqian Li
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
| | - Jingjing Li
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
| | - Peihua Lu
- Hebei Yanda Lu Daopei Hospital, Langfang, P.R. China
- Beijing Lu Daopei Institute of Hematology, Beijing, P.R. China
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5
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Zhang X, Geng L, Yang L, Wang Y, Zou Z, Zhang Y, Xu H, Lei H, Cao Y, Wu Y, Gu W, Zhou L. Anlotinib exerts an anti-T-cell acute lymphoblastic leukemia effect in vitro and in vivo. Cell Signal 2023; 110:110837. [PMID: 37544636 DOI: 10.1016/j.cellsig.2023.110837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023]
Abstract
BACKGROUND Despite some progress having been made regarding the treatment of T-cell acute lymphoblastic leukemia (T-ALL), the prognosis of T-ALL, particularly adult T-ALL, is still poor. Identifying novel, effective anti-T-ALL drugs is of great significance. Anlotinib, an oral tyrosine kinase inhibitor currently utilized in the treatment of lung cancer, exhibited a promising anti-T-ALL effect. A comprehensive study should therefore be conducted to explore both the in vitro as well as in vivo mechanisms of the anti-T-ALL effects of anlotinib. METHODS CCK8 assays and flow cytometry were employed to investigate the viability, cell cycle distribution, and apoptosis of T-ALL cell lines when treated with anlotinib. T-ALL xenograft mouse models were established to examine the in vivo antileukemic effects of anlotinib. Cellular and molecular analysis of T-ALL were conducted to define the underlying mechanisms. RESULTS In vitro, anlotinib significantly inhibited the viability, induced G2/M phase arrest and apoptosis in T-ALL cell lines in a concentration-dependent pattern. In vivo, anlotinib also demonstrated a strong anti-tumor effect at doses that are well-tolerated. Interestingly, anlotinib could decrease the protein levels of the intracellular domains of NOTCH1 (ICN1) and c-Myc, two important targets for T-ALL. Mechanistically, anlotinib-induced c-Myc reduction was associated with proteasome-mediated degradation, while the ICN1 reduction was not due to protein degradation or transcriptional repression. CONCLUSIONS The present study showed that anlotinib may be a promising anti-T-ALL candidate drug, and simultaneous reduction of the protein levels of both ICN1 and c-Myc may contribute to the anti-T-ALL efficacy of anlotinib.
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Affiliation(s)
- Xingming Zhang
- Department of Clinical Laboratory, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Rd, Shanghai 200011, China
| | - Lou Geng
- Department of Clinical Laboratory, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Rd, Shanghai 200011, China
| | - Li Yang
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yingying Wang
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Zhihui Zou
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Youping Zhang
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Hanzhang Xu
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Hu Lei
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yang Cao
- Department of Hematology, The First People's Hospital of Changzhou, Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu Province P.R. 213003, China
| | - Yingli Wu
- Hongqiao International Institute of Medicine, Shanghai Tongren Hospital / Faculty of Basic Medicine, Chemical Biology Division of Shanghai Universities E-Institutes, Key Laboratory of Cell Differentiation and Apoptosis of the Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wenli Gu
- Department of Clinical Laboratory, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Rd, Shanghai 200011, China.
| | - Li Zhou
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, No.197, Ruijin Er Road, Shanghai 200025, China.
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6
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MNT suppresses T cell apoptosis via BIM and is critical for T lymphomagenesis. Cell Death Differ 2023; 30:1018-1032. [PMID: 36755068 PMCID: PMC10070419 DOI: 10.1038/s41418-023-01119-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 02/10/2023] Open
Abstract
The importance of c-MYC in regulating lymphopoiesis and promoting lymphomagenesis is well-established. Far less appreciated is the vital supporting role of MYC's relative MNT. Using Rag1Cre-mediated Mnt deletion in lymphoid progenitor cells, we show here that, during normal T cell development, MNT loss enhances apoptosis, at least in part by elevating expression of the pro-apoptotic BH3-only protein BIM. Moreover, using T lymphoma-prone VavP-MYC transgenic mice, we show that Mnt deletion reduces the pool of pre-malignant MYC-driven T lymphoid cells and abrogates thymic T lymphomagenesis. In addition, we establish that Mnt deletion prevents T lymphoma development in γ-irradiated mice, most likely by enhancing apoptosis of T lymphoid cells repopulating the depleted thymus. Taken together with our recent demonstration that MNT is vital for the survival of MYC-driven pre-malignant and malignant B lymphoid cells, these results suggest that MNT represents an important new drug target for both T and B lymphoid malignancies.
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7
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Toribio ML, González-García S. Notch Partners in the Long Journey of T-ALL Pathogenesis. Int J Mol Sci 2023; 24:ijms24021383. [PMID: 36674902 PMCID: PMC9866461 DOI: 10.3390/ijms24021383] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023] Open
Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological disease that arises from the oncogenic transformation of developing T cells during T-lymphopoiesis. Although T-ALL prognosis has improved markedly in recent years, relapsing and refractory patients with dismal outcomes still represent a major clinical issue. Consequently, understanding the pathological mechanisms that lead to the appearance of this malignancy and developing novel and more effective targeted therapies is an urgent need. Since the discovery in 2004 that a major proportion of T-ALL patients carry activating mutations that turn NOTCH1 into an oncogene, great efforts have been made to decipher the mechanisms underlying constitutive NOTCH1 activation, with the aim of understanding how NOTCH1 dysregulation converts the physiological NOTCH1-dependent T-cell developmental program into a pathological T-cell transformation process. Several molecular players have so far been shown to cooperate with NOTCH1 in this oncogenic process, and different therapeutic strategies have been developed to specifically target NOTCH1-dependent T-ALLs. Here, we comprehensively analyze the molecular bases of the cross-talk between NOTCH1 and cooperating partners critically involved in the generation and/or maintenance and progression of T-ALL and discuss novel opportunities and therapeutic approaches that current knowledge may open for future treatment of T-ALL patients.
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8
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Wang X, Langer EM, Daniel CJ, Janghorban M, Wu V, Wang XJ, Sears RC. Altering MYC phosphorylation in the epidermis increases the stem cell population and contributes to the development, progression, and metastasis of squamous cell carcinoma. Oncogenesis 2020; 9:79. [PMID: 32895364 PMCID: PMC7477541 DOI: 10.1038/s41389-020-00261-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/06/2020] [Accepted: 08/13/2020] [Indexed: 12/31/2022] Open
Abstract
cMYC (MYC) is a potent oncoprotein that is subject to post-translational modifications that affect its stability and activity. Here, we show that Serine 62 phosphorylation, which increases MYC stability and oncogenic activity, is elevated while Threonine 58 phosphorylation, which targets MYC for degradation, is decreased in squamous cell carcinoma (SCC). The oncogenic role of MYC in the development of SCC is unclear since studies have shown in normal skin that wild-type MYC overexpression can drive loss of stem cells and epidermal differentiation. To investigate whether and how altered MYC phosphorylation might affect SCC development, progression, and metastasis, we generated mice with inducible expression of MYCWT or MYCT58A in the basal layer of the skin epidermis. In the T58A mutant, MYC is stabilized with constitutive S62 phosphorylation. When challenged with DMBA/TPA-mediated carcinogenesis, MYCT58A mice had accelerated development of papillomas, increased conversion to malignant lesions, and increased metastasis as compared to MYCWT mice. In addition, MYCT58A-driven SCC displayed stem cell gene expression not observed with MYCWT, including increased expression of Lgr6, Sox2, and CD34. In support of MYCT58A enhancing stem cell phenotypes, its expression was associated with an increased number of BrdU long-term label-retaining cells, increased CD34 expression in hair follicles, and increased colony formation from neonatal keratinocytes. Together, these results indicate that altering MYC phosphorylation changes its oncogenic activity—instead of diminishing establishment and/or maintenance of epidermal stem cell populations like wild-type MYC, pS62-MYC enhances these populations and, under carcinogenic conditions, pS62-MYC expression results in aggressive tumor phenotypes.
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Affiliation(s)
- Xiaoyan Wang
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Ellen M Langer
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA.,Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Colin J Daniel
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Mahnaz Janghorban
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Vivian Wu
- Department of Otolaryngology-HNS, Henry Ford Health System, Detroit, MI, USA
| | - Xiao-Jing Wang
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA.,Veterans Affairs Medical Center, VA Eastern Colorado Health Care System, Aurora, CO, USA
| | - Rosalie C Sears
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA. .,Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA.
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9
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Benetatos L, Benetatou A, Vartholomatos G. Long non-coding RNAs and MYC association in hematological malignancies. Ann Hematol 2020; 99:2231-2242. [PMID: 32621182 DOI: 10.1007/s00277-020-04166-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/29/2020] [Indexed: 12/19/2022]
Abstract
Long non-coding RNAs (lncRNAs) have an established role in cell biology. Among their functions is the regulation of hematopoiesis. They characterize the different stages of hematopoiesis in a more lineage-restricted expression pattern than coding mRNAs. They affect hematopoietic stem cell renewal, proliferation, and differentiation of committed progenitors by interacting with master regulators transcription factors. Among these transcription factors, MYC has a prominent role. Similar to MYC's transcriptional activation/amplification of protein coding genes, MYC also regulates lncRNAs' expression profile, while it is also regulated by lncRNAs. Both myeloid and lymphoid malignancies are prone to the association of MYC with lncRNAs. Such interaction inhibits apoptosis, enhances cell proliferation, deregulates metabolism, and promotes genomic instability and resistance to treatment. In this review, we discuss the recent findings that encompass the crosstalk between lncRNAs and describe the pathways that very probably have a pathogenetic role in both acute and chronic hematologic malignancies.
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Affiliation(s)
| | - Agapi Benetatou
- Department of Pharmacy, School of Health Sciences, University of Patras, Patras, Greece
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10
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Myc-Miz1 signaling promotes self-renewal of leukemia stem cells by repressing Cebpα and Cebpδ. Blood 2020; 135:1133-1145. [PMID: 32040550 PMCID: PMC9981456 DOI: 10.1182/blood.2019001863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 01/08/2020] [Indexed: 11/20/2022] Open
Abstract
c-Myc (Myc hereafter) is found to be deregulated and/or amplified in most acute myeloid leukemias (AMLs). Almost all AML cells are dependent upon Myc for their proliferation and survival. Thus, Myc has been proposed as a critical anti-AML target. Myc has Max-mediated transactivational and Myc-interacting zinc finger protein 1 (Miz1)-mediated transrepressional activities. The role of Myc-Max-mediated transactivation in the pathogenesis of AML has been well studied; however, the role of Myc-Miz1-mediated transrepression in AML is still somewhat obscure. Myc protein harboring a V394D mutation (MycV394D) is a mutant form of Myc that lacks transrepressional activity due to a defect in its ability to interact with Miz1. We found that, compared with Myc, the oncogenic function of MycV394D is significantly impaired. The AML/myeloproliferative disorder that develops in mice receiving MycV394D-transduced hematopoietic stem/progenitor cells (HSPCs) is significantly delayed compared with mice receiving Myc-transduced HSPCs. Using a murine MLL-AF9 AML model, we found that AML cells expressing MycV394D (intrinsic Myc deleted) are partially differentiated and show reductions in both colony-forming ability in vitro and leukemogenic capacity in vivo. The reduced frequency of leukemia stem cells (LSCs) among MycV394D-AML cells and their reduced leukemogenic capacity during serial transplantation suggest that Myc-Miz1 interaction is required for the self-renewal of LSCs. In addition, we found that MycV394D-AML cells are more sensitive to chemotherapy than are Myc-AML cells. Mechanistically, we found that Myc represses Miz1-mediated expression of CCAAT/enhancer-binding protein α (Cebpα) and Cebpδ, thus playing an important role in the pathogenesis of AML by maintaining the undifferentiated state and self-renewal capacity of LSCs.
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11
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Wang F, Lv H, Zhao B, Zhou L, Wang S, Luo J, Liu J, Shang P. Iron and leukemia: new insights for future treatments. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:406. [PMID: 31519186 PMCID: PMC6743129 DOI: 10.1186/s13046-019-1397-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/27/2019] [Indexed: 01/19/2023]
Abstract
Iron, an indispensable element for life, is involved in all kinds of important physiological activities. Iron promotes cell growth and proliferation, but it also causes oxidative stress damage. The body has a strict regulation mechanism of iron metabolism due to its potential toxicity. As a cancer of the bone marrow and blood cells, leukemia threatens human health seriously. Current studies suggest that dysregulation of iron metabolism and subsequent accumulation of excess iron are closely associated with the occurrence and progress of leukemia. Specifically, excess iron promotes the development of leukemia due to the pro-oxidative nature of iron and its damaging effects on DNA. On the other hand, leukemia cells acquire large amounts of iron to maintain rapid growth and proliferation. Therefore, targeting iron metabolism may provide new insights for approaches to the treatment of leukemia. This review summarizes physiologic iron metabolism, alternations of iron metabolism in leukemia and therapeutic opportunities of targeting the altered iron metabolism in leukemia, with a focus on acute leukemia.
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Affiliation(s)
- Fang Wang
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Huanhuan Lv
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China.,Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, 518057, China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Bin Zhao
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Liangfu Zhou
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Shenghang Wang
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Jie Luo
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Junyu Liu
- School of Life Science, Northwestern Polytechnical University, Xi'an, 710072, China
| | - Peng Shang
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, 518057, China. .,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, 710072, China.
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12
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Huang BJ, Wandler AM, Meyer LK, Dail M, Daemen A, Sampath D, Li Q, Wang X, Wong JC, Nakitandwe J, Downing JR, Zhang J, Taylor BS, Shannon K. Convergent genetic aberrations in murine and human T lineage acute lymphoblastic leukemias. PLoS Genet 2019; 15:e1008168. [PMID: 31199785 PMCID: PMC6594654 DOI: 10.1371/journal.pgen.1008168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/26/2019] [Accepted: 04/29/2019] [Indexed: 12/22/2022] Open
Abstract
The lack of predictive preclinical models is a fundamental barrier to translating knowledge about the molecular pathogenesis of cancer into improved therapies. Insertional mutagenesis (IM) in mice is a robust strategy for generating malignancies that recapitulate the extensive inter- and intra-tumoral genetic heterogeneity found in advanced human cancers. While the central role of "driver" viral insertions in IM models that aberrantly increase the expression of proto-oncogenes or disrupt tumor suppressors has been appreciated for many years, the contributions of cooperating somatic mutations and large chromosomal alterations to tumorigenesis are largely unknown. Integrated genomic studies of T lineage acute lymphoblastic leukemias (T-ALLs) generated by IM in wild-type (WT) and Kras mutant mice reveal frequent point mutations and other recurrent non-insertional genetic alterations that also occur in human T-ALL. These somatic mutations are sensitive and specific markers for defining clonal dynamics and identifying candidate resistance mechanisms in leukemias that relapse after an initial therapeutic response. Primary cancers initiated by IM and resistant clones that emerge during in vivo treatment close key gaps in existing preclinical models, and are robust platforms for investigating the efficacy of new therapies and for elucidating how drug exposure shapes tumor evolution and patterns of resistance. A lack of predictive cancer models is a major bottleneck for prioritizing new anti-cancer drugs for clinical trials. We comprehensively profiled a panel of primary mouse T lineage leukemias initiated by insertional mutagenesis and found remarkable similarities with human T-ALL in regard to overall mutational burden, the occurrence of specific somatic mutations and large chromosomal alterations, and concordant gene expression signatures. We observed frequent duplication of the Kras oncogene with loss of the normal allele, which has potential therapeutic implications that merit further investigation in human leukemia and in other preclinical models. Mutations identified in mouse leukemias that relapsed after in vivo treatment with signal transduction inhibitors were also observed in relapsed human T-ALL, indicating that this model system can be utilized to investigate strategies for overcoming intrinsic and acquired drug resistance. Finally, preclinical models similar to the one described here that are characterized by a normal endogenous tumor microenvironment and intact immune system will become increasingly important for testing immunotherapy approaches for human cancer.
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Affiliation(s)
- Benjamin J. Huang
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Anica M. Wandler
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Lauren K. Meyer
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Monique Dail
- Department of Oncology Biomarker Development, Genentech, South San Francisco, CA, United States of America
| | - Anneleen Daemen
- Department of Bioinformatics & Computational Biology, Genentech, South San Francisco, CA, United States of America
| | - Deepak Sampath
- Department of Translational Oncology, Genentech, South San Francisco, CA, United States of America
| | - Qing Li
- Division of Hematology/Oncology, Department of Medicine, University of Michigan, Ann Arbor, MI, United States of America
| | - Xinyue Wang
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Jasmine C. Wong
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Joy Nakitandwe
- Department of Pathology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - James R. Downing
- Department of Pathology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Jinghui Zhang
- Department of Computational Biology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Barry S. Taylor
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
| | - Kevin Shannon
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, United States of America
- * E-mail:
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13
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Ohanian M, Rozovski U, Kanagal-Shamanna R, Abruzzo LV, Loghavi S, Kadia T, Futreal A, Bhalla K, Zuo Z, Huh YO, Post SM, Ruvolo P, Garcia-Manero G, Andreeff M, Kornblau S, Borthakur G, Hu P, Medeiros LJ, Takahashi K, Hornbaker MJ, Zhang J, Nogueras-González GM, Huang X, Verstovsek S, Estrov Z, Pierce S, Ravandi F, Kantarjian HM, Bueso-Ramos CE, Cortes JE. MYC protein expression is an important prognostic factor in acute myeloid leukemia. Leuk Lymphoma 2019; 60:37-48. [PMID: 29741984 PMCID: PMC6226369 DOI: 10.1080/10428194.2018.1464158] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
As new drugs targeting MYC show clinical activity in acute myeloid leukemia (AML), understanding MYC expression in AML is of critical importance. We assessed MYC protein expression by immunohistochemistry in bone marrow of patients with untreated AML (n = 265). Overall, 90% of patients demonstrated MYC overexpression and MYC immunopositivity ≤6% was associated with superior complete remission (CR) duration of 23 months versus 12 months for MYC immunopositivity >6% (p = .028). Among 241 patients at higher risk for relapse, including those ≥55 years of age and patients with intermediate- and high-risk AML, MYC immunopositivity ≤6% conferred significantly superior median overall survival (OS) (24 versus 13 months; p = .042), event-free survival (EFS) (14 versus 6 months; p = .048), and relapse-free survival (RFS) (25 versus 12 months; p = .024). The prognostic impact of MYC-immunopositivity was retained on multivariate analysis of OS, EFS, and RFS. We conclude that MYC immunopositivity is an important prognostic factor in patients with untreated AML, particularly those at higher risk for relapse.
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Affiliation(s)
- Maro Ohanian
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Uri Rozovski
- Department of Hematology, Davidoff Cancer Center at Rabin Medical Center, Sackler School of Medicine, Tel Aviv University, Israel
| | - Rashmi Kanagal-Shamanna
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Lynne V. Abruzzo
- Department of Pathology, Ohio State University, Columbus, OH 43202
| | - Sanam Loghavi
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Tapan Kadia
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Andrew Futreal
- Department of Genomic Medicine, The University of Texas at MD Anderson Cancer Center, Houston, TX
| | - Kapil Bhalla
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Zhuang Zuo
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Yang O. Huh
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Sean M. Post
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Peter Ruvolo
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Guillermo Garcia-Manero
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Michael Andreeff
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Steven Kornblau
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Gautam Borthakur
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Peter Hu
- School of Health Professions, The University of Texas at MD Anderson Cancer Center, Houston, TX
| | - L. Jeffrey Medeiros
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Koichi Takahashi
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Marisa J. Hornbaker
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Jianhua Zhang
- Department of Genomic Medicine, The University of Texas at MD Anderson Cancer Center, Houston, TX
| | | | - Xuelin Huang
- Department of Biostatistics, The University of Texas at MD Anderson Cancer Center, Houston, TX
| | - Srdan Verstovsek
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Zeev Estrov
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Sherry Pierce
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Farhad Ravandi
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Hagop M. Kantarjian
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
| | - Carlos E. Bueso-Ramos
- Department of Hematopathology, The University of Texas at MD Anderson Cancer Center Houston, Texas
| | - Jorge E. Cortes
- Department of Leukemia, The University of Texas at MD Anderson Cancer Center, Houston, Texas
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14
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Takimoto-Shimomura T, Tsukamoto T, Maegawa S, Fujibayashi Y, Matsumura-Kimoto Y, Mizuno Y, Chinen Y, Shimura Y, Mizutani S, Horiike S, Taniwaki M, Kobayashi T, Kuroda J. Dual targeting of bromodomain-containing 4 by AZD5153 and BCL2 by AZD4320 against B-cell lymphomas concomitantly overexpressing c-MYC and BCL2. Invest New Drugs 2018; 37:210-222. [PMID: 29931583 DOI: 10.1007/s10637-018-0623-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 06/11/2018] [Indexed: 01/18/2023]
Abstract
Despite the recent therapeutic progress, the prognoses of diffuse large B-cell lymphomas (DLBCLs) that concomitantly overexpress c-MYC and BCL2, i.e., double hit lymphoma (DHL) and double expressing lymphoma (DEL), remain poor. This study examined triple targeting of c-MYC, BCL2 and the B-cell receptor (BCR) signaling pathway for DHL and DEL. We first used AZD5153, a novel bivalent inhibitor for bromodomain-containing 4 (BRD4), in DHL- and DEL-derived cell lines, because BRD4 regulates disease type-oriented key molecules for oncogenesis. AZD5153 was more effective than conventional monovalent BRD4 inhibitors, JQ1 and I-BET151, in inhibiting cell proliferation of a DHL-derived cell line and two DEL-derived cell lines, with at least 10-fold lower half growth inhibitory concentrations. AZD5153 caused G1/S cell cycle blockade, while the apoptosis-inducing effect was relatively modest. At the molecular level, AZD5153 was potent in downregulating various molecules for oncogenesis, such as c-MYC, AKT2 and MAP3K; those involved in the BCR signaling pathway, such as CD19, BLNK and CD79B; and those associated with B-cell development, such as IKZF1, IKZF3, PAX5, POU2AF1 and EBF1. In contrast, AZD5153 did not decrease anti-apoptotic BCL2 proteins, and did not activate pro-apoptotic BH3-only proteins, except BAD. To augment cell death induction, we added a novel BH3-mimicking BCL2 inhibitor AZD4320 to AZD5153, and found that these two agents had a mostly synergistic antitumor effect by increasing cells undergoing apoptosis in all three cell lines. These results provide a rationale for dual targeting of BRD4 and BCL2 using AZD5153 and AZD4320 as a therapeutic strategy against DHL and DEL.
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Affiliation(s)
- Tomoko Takimoto-Shimomura
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Taku Tsukamoto
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Saori Maegawa
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yuto Fujibayashi
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yayoi Matsumura-Kimoto
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yoshimi Mizuno
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yoshiaki Chinen
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yuji Shimura
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Shinsuke Mizutani
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Shigeo Horiike
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Masafumi Taniwaki
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Tsutomu Kobayashi
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Junya Kuroda
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
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15
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Högstrand K, Darmanin S, Forshell TP, Grandien A. Transformation of mouse T cells requires MYC and AKT activity in conjunction with inhibition of intrinsic apoptosis. Oncotarget 2018; 9:21396-21410. [PMID: 29765548 PMCID: PMC5940390 DOI: 10.18632/oncotarget.25113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 03/15/2018] [Indexed: 12/13/2022] Open
Abstract
Peripheral T-cell lymphoma is an aggressive non-Hodgkin's lymphoma characterized by excessive proliferation of transformed mature T cells. The number and nature of genetic aberrations required and sufficient for transformation of normal T cells into lymphomas is unknown. Here, using a combinatorial in vitro-approach, we demonstrate that overexpression of MYC together with activated AKT in conditions of inhibition of intrinsic apoptosis rapidly resulted in transformation of mature mouse T cells with a frequency approaching 100%. Injection of transformed cells into mice resulted in rapid development of aggressive T cell lymphoma, characterized by spread to several organs, destruction of tissue architecture and rapid death of the animals. TcR-sequencing revealed a polyclonal repertoire of tumor cells indicating that co-expression of MYC, activated AKT and BCLXL is sufficient for tumor transformation and do not require acquisition of additional genetic events. When analyzing cells with inducible expression we found that proliferation of transformed T cells required sustained expression of both MYC and AKT. AKT exerted a dual function as it inhibited induction of, and promoted exit from, cellular quiescence and contributed to inhibion of apoptosis. Downregulation of AKT and/or MYC together with BCLXL resulted in rapid and complete elimination of cells through induction of apoptotic cell death.
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Affiliation(s)
- Kari Högstrand
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge, 141 57 Stockholm, Sweden
| | - Stephanie Darmanin
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge, 141 57 Stockholm, Sweden
| | - TachaZi Plym Forshell
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge, 141 57 Stockholm, Sweden
| | - Alf Grandien
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge, 141 57 Stockholm, Sweden
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16
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Lombardi O, Varshney D, Phillips NM, Cowling VH. c-Myc deregulation induces mRNA capping enzyme dependency. Oncotarget 2018; 7:82273-82288. [PMID: 27756891 PMCID: PMC5347691 DOI: 10.18632/oncotarget.12701] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/10/2016] [Indexed: 01/24/2023] Open
Abstract
c-Myc is a potent driver of many human cancers. Since strategies for directly targeting c-Myc protein have had limited success, upstream regulators and downstream effectors of c-Myc are being investigated as alternatives for therapeutic intervention. c-Myc regulates transcription and formation of the mRNA cap, which is important for transcript maturation and translation. However, the direct mechanism by which c-Myc upregulates mRNA capping is unclear. mRNA cap formation initiates with the linkage of inverted guanosine via a triphosphate bridge to the first transcribed nucleotide, catalysed by mRNA capping enzyme (CE/RNGTT). Here we report that c-Myc increases the recruitment of catalytically active CE to RNA polymerase II and to its target genes. c-Myc-induced target gene expression, cell proliferation and cell transformation is highly dependent on CE, but only when c-Myc is deregulated. Cells retaining normal control of c-Myc expression are insensitive to repression of CE. c-Myc expression is also dependent on CE. Therefore, inhibiting CE provides an attractive route for selective therapeutic targeting of cancer cells which have acquired deregulated c-Myc.
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Affiliation(s)
- Olivia Lombardi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Dhaval Varshney
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Nicola M Phillips
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.,School of Science and the Environment, Manchester Metropolitan University, Manchester, M15 6BH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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17
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Campbell KJ, Vandenberg CJ, Anstee NS, Hurlin PJ, Cory S. Mnt modulates Myc-driven lymphomagenesis. Cell Death Differ 2017; 24:2117-2126. [PMID: 28800127 PMCID: PMC5686348 DOI: 10.1038/cdd.2017.131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/06/2017] [Indexed: 12/27/2022] Open
Abstract
The transcriptional represser Mnt is a functional antagonist of the proto-oncoprotein Myc. Both Mnt and Myc utilise Max as an obligate partner for DNA binding, and Myc/Max and Mnt/Max complexes compete for occupancy at E-box DNA sequences in promoter regions. We have previously shown in transgenic mouse models that the phenotype and kinetics of onset of haemopoietic tumours varies with the level of Myc expression. We reasoned that a decrease in the level of Mnt would increase the functional level of Myc and accelerate Myc-driven tumorigenesis. We tested the impact of reduced Mnt in three models of myc transgenic mice and in p53+/- mice. To our surprise, mnt heterozygosity actually slowed Myc-driven tumorigenesis in vavP-MYC10 and Eμ-myc mice, suggesting that Mnt facilitates Myc-driven oncogenesis. To explore the underlying cause of the delay in tumour development, we enumerated Myc-driven cell populations in healthy young vavP-MYC10 and Eμ-myc mice, expecting that the reduced rate of leukaemogenesis in mnt heterozygous mice would be reflected in a reduced number of preleukaemic cells, due to increased apoptosis or reduced proliferation or both. However, no differences were apparent. Furthermore, when mnt+/+ and mnt+/- pre-B cells from healthy young Eμ-myc mice were compared in vitro, no differences were seen in their sensitivity to apoptosis or in cell size or cell cycling. Moreover, the frequencies of apoptotic, senescent and proliferating cells were comparable in vivo in mnt+/- and mnt+/+ Eμ-myc lymphomas. Thus, although mnt heterozygosity clearly slowed lymphomagenesis in vavP-MYC10 and Eμ-myc mice, the change(s) in cellular properties responsible for this effect remain to be identified.
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Affiliation(s)
- Kirsteen J Campbell
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, VIC 3052, Australia
| | - Cassandra J Vandenberg
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Natasha S Anstee
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Suzanne Cory
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC 3010, Australia
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18
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Affiliation(s)
- Becca Asquith
- Department of Medicine, Imperial College London, London, UK
| | - Rob J de Boer
- Theoretical Biology and Bioinformatics, Utrecht University, the Netherlands
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19
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The NOTCH1-MYC highway toward T-cell acute lymphoblastic leukemia. Blood 2017; 129:1124-1133. [PMID: 28115368 DOI: 10.1182/blood-2016-09-692582] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/14/2016] [Indexed: 12/21/2022] Open
Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is a highly proliferative hematologic malignancy that results from the transformation of immature T-cell progenitors. Aberrant cell growth and proliferation in T-ALL lymphoblasts are sustained by activation of strong oncogenic drivers promoting cell anabolism and cell cycle progression. Oncogenic NOTCH signaling, which is activated in more than 65% of T-ALL patients by activating mutations in the NOTCH1 gene, has emerged as a major regulator of leukemia cell growth and metabolism. T-ALL NOTCH1 mutations result in ligand-independent and sustained NOTCH1-receptor signaling, which translates into activation of a broad transcriptional program dominated by upregulation of genes involved in anabolic pathways. Among these, the MYC oncogene plays a major role in NOTCH1-induced transformation. As result, the oncogenic activity of NOTCH1 in T-ALL is strictly dependent on MYC upregulation, which makes the NOTCH1-MYC regulatory circuit an attractive therapeutic target for the treatment of T-ALL.
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20
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Heinzel S, Binh Giang T, Kan A, Marchingo JM, Lye BK, Corcoran LM, Hodgkin PD. A Myc-dependent division timer complements a cell-death timer to regulate T cell and B cell responses. Nat Immunol 2016; 18:96-103. [PMID: 27820810 DOI: 10.1038/ni.3598] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/29/2016] [Indexed: 12/29/2022]
Abstract
T lymphocytes and B lymphocytes integrate activating signals to control the size of their proliferative response. Here we report that such control was achieved by timed changes in the production rate of cell-cycle-regulating proto-oncoprotein Myc, with division cessation occurring when Myc levels fell below a critical threshold. The changing pattern of the level of Myc was not affected by cell division, which identified the regulating mechanism as a cell-intrinsic, heritable temporal controller. Overexpression of Myc in stimulated T cells and B cells did not sustain cell proliferation indefinitely, as a separate 'time-to-die' mechanism, also heritable, was programmed after lymphocyte activation and led to eventual cell loss. Together the two competing cell-intrinsic timed fates created the canonical T cell and B cell immune-response pattern of rapid growth followed by loss of most cells. Furthermore, small changes in these timed processes by regulatory signals, or by oncogenic transformation, acted in synergy to greatly enhance cell numbers over time.
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Affiliation(s)
- Susanne Heinzel
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Tran Binh Giang
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Andrey Kan
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Julia M Marchingo
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Bryan K Lye
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Lynn M Corcoran
- Department of Medical Biology, The University of Melbourne, Parkville, Australia.,Division of Molecular Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Philip D Hodgkin
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
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21
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Anderson NM, Li D, Peng HL, Laroche FJF, Mansour MR, Gjini E, Aioub M, Helman DJ, Roderick JE, Cheng T, Harrold I, Samaha Y, Meng L, Amsterdam A, Neuberg DS, Denton TT, Sanda T, Kelliher MA, Singh A, Look AT, Feng H. The TCA cycle transferase DLST is important for MYC-mediated leukemogenesis. Leukemia 2016; 30:1365-74. [PMID: 26876595 DOI: 10.1038/leu.2016.26] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/21/2015] [Accepted: 02/01/2016] [Indexed: 12/22/2022]
Abstract
Despite the pivotal role of MYC in the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) and many other cancers, the mechanisms underlying MYC-mediated tumorigenesis remain inadequately understood. Here we utilized a well-characterized zebrafish model of Myc-induced T-ALL for genetic studies to identify novel genes contributing to disease onset. We found that heterozygous inactivation of a tricarboxylic acid (TCA) cycle enzyme, dihydrolipoamide S-succinyltransferase (Dlst), significantly delayed tumor onset in zebrafish without detectable effects on fish development. DLST is the E2 transferase of the α-ketoglutarate (α-KG) dehydrogenase complex (KGDHC), which converts α-KG to succinyl-CoA in the TCA cycle. RNAi knockdown of DLST led to decreased cell viability and induction of apoptosis in human T-ALL cell lines. Polar metabolomics profiling revealed that the TCA cycle was disrupted by DLST knockdown in human T-ALL cells, as demonstrated by an accumulation of α-KG and a decrease of succinyl-CoA. Addition of succinate, the downstream TCA cycle intermediate, to human T-ALL cells was sufficient to rescue defects in cell viability caused by DLST inactivation. Together, our studies uncovered an important role for DLST in MYC-mediated leukemogenesis and demonstrated the metabolic dependence of T-lymphoblasts on the TCA cycle, thus providing implications for targeted therapy.
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Affiliation(s)
- N M Anderson
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - D Li
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - H L Peng
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Division of Hematology/Institute of Molecular Hematology, Second Xiang-Ya Hospital, Central South University, Changsha, China
| | - F J F Laroche
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - M R Mansour
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - E Gjini
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - M Aioub
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - D J Helman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - J E Roderick
- Department of Cancer Biology, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - T Cheng
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - I Harrold
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - Y Samaha
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - L Meng
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - A Amsterdam
- David H Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - D S Neuberg
- Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - T T Denton
- Department of Pharmaceutical Sciences, Washington State University, College of Pharmacy, Spokane, WA, USA
| | - T Sanda
- Department of Medicine, Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - M A Kelliher
- Department of Cancer Biology, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - A Singh
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
| | - A T Look
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - H Feng
- Departments of Pharmacology and Medicine, The Center for Cancer Research, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA, USA
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22
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Abstract
This study demonstrates, for the first time, that loss of a single forkhead box class O (FoxO) transcription factor, can promote lymphomagenesis. Using two different mouse models, we show that FoxO3 has a significant tumour-suppressor function in the context of Myc-driven lymphomagenesis. Loss of FoxO3 significantly accelerated myeloid tumorigenesis in vavP-MYC10 transgenic mice and B lymphomagenesis in Eμ-myc transgenic mice. Tumour analysis indicated that the selective pressure for mutation of the p53 pathway during Eμ-myc lymphomagenesis was not altered. Frank tumours were preceded by elevated macrophage numbers in FoxO3(-/-) vavP-MYC10 mice but, surprisingly, pre-B-cell numbers were relatively normal in healthy young FoxO3(-/-)Eμ-myc mice. In vitro assays revealed enhanced survival capacity of Myc-driven cells lacking FoxO3, but no change in cell cycling was detected. The loss of FoxO3 may also be affecting other tumour-suppressive functions for which FoxO1/4 cannot fully compensate.
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23
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Nguyen LT, Tretiakova MS, Silvis MR, Lucas J, Klezovitch O, Coleman I, Bolouri H, Kutyavin VI, Morrissey C, True LD, Nelson PS, Vasioukhin V. ERG Activates the YAP1 Transcriptional Program and Induces the Development of Age-Related Prostate Tumors. Cancer Cell 2015; 27:797-808. [PMID: 26058078 PMCID: PMC4461839 DOI: 10.1016/j.ccell.2015.05.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 11/17/2014] [Accepted: 05/07/2015] [Indexed: 12/30/2022]
Abstract
The significance of ERG in human prostate cancer is unclear because mouse prostate is resistant to ERG-mediated transformation. We determined that ERG activates the transcriptional program regulated by YAP1 of the Hippo signaling pathway and found that prostate-specific activation of either ERG or YAP1 in mice induces similar transcriptional changes and results in age-related prostate tumors. ERG binds to chromatin regions occupied by TEAD/YAP1 and transactivates Hippo target genes. In addition, in human luminal-type prostate cancer cells, ERG binds to the promoter of YAP1 and is necessary for YAP1 expression. These results provide direct genetic evidence of a causal role for ERG in prostate cancer and reveal a connection between ERG and the Hippo signaling pathway.
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Affiliation(s)
- Liem T Nguyen
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Maria S Tretiakova
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Mark R Silvis
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jared Lucas
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Olga Klezovitch
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Ilsa Coleman
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Hamid Bolouri
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Vassily I Kutyavin
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Colm Morrissey
- Department of Urology, University of Washington, Seattle, WA 98195, USA
| | - Lawrence D True
- Department of Pathology, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Peter S Nelson
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Urology, University of Washington, Seattle, WA 98195, USA; Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Valeri Vasioukhin
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Pathology, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA.
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24
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Abstract
MYC translocations represent a genetic subtype of T-lineage acute lymphoblastic leukemia (T-ALL), which occurs at an incidence of ∼6%, assessed within a cohort of 196 T-ALL patients (64 adults and 132 children). The translocations were of 2 types; those rearranged with the T-cell receptor loci and those with other partners. MYC translocations were significantly associated with the TAL/LMO subtype of T-ALL (P = .018) and trisomies 6 (P < .001) and 7 (P < .001). Within the TAL/LMO subtype, gene expression profiling identified 148 differentially expressed genes between patients with and without MYC translocations; specifically, 77 were upregulated and 71 downregulated in those with MYC translocations. The poor prognostic marker, CD44, was among the upregulated genes. MYC translocations occurred as secondary abnormalities, present in subclones in one-half of the cases. Longitudinal studies indicated an association with induction failure and relapse.
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25
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Loosveld M, Bonnet M, Gon S, Montpellier B, Quilichini B, Navarro JM, Crouzet T, Goujart MA, Chasson L, Morgado E, Picard C, Hernandez L, Fossat C, Gabert J, Michel G, Nadel B, Payet-Bornet D. MYC fails to efficiently shape malignant transformation in T-cell acute lymphoblastic leukemia. Genes Chromosomes Cancer 2014; 53:52-66. [DOI: 10.1002/gcc.22117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Affiliation(s)
- Marie Loosveld
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
- Department of Hematology; AP-HM La Timone; 13385 Marseille France
| | - Mélanie Bonnet
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Stéphanie Gon
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Bertrand Montpellier
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | | | - Jean-Marc Navarro
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Thomas Crouzet
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Marie-Amélie Goujart
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
- Department of Hematology; AP-HM La Timone; 13385 Marseille France
| | - Lionel Chasson
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Ester Morgado
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Christophe Picard
- UMR 7268; Anthropologie Bio-culturelle; Droit, Ethique et Santé - ADES
| | - Lucie Hernandez
- Hematology Laboratory; AP-HP, Hôpital Saint-Louis 75010 Paris France
| | - Chantal Fossat
- Department of Hematology; AP-HM La Timone; 13385 Marseille France
| | - Jean Gabert
- Université de la Méditerranée IFR 11; Marseille France
- Biochemistry and molecular Biology Laboratory; AP-HM Hopital Nord; Marseille France
| | - Gérard Michel
- Department of Hematology; AP-HM La Timone; 13385 Marseille France
| | - Bertrand Nadel
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
| | - Dominique Payet-Bornet
- Centre d'Immunologie de Marseille-Luminy; Aix-Marseille Université; 13288 Marseille France
- INSERM U1104
- CNRS UMR7280; 13288 Marseille France
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26
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Trop-Steinberg S, Azar Y, Or R. Early cell-cycle gene expression in T-cells after hematopoietic stem cell transplantation. Transpl Immunol 2013; 29:146-54. [DOI: 10.1016/j.trim.2013.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 03/24/2013] [Accepted: 03/25/2013] [Indexed: 01/19/2023]
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27
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Carofino BL, Ayanga B, Justice MJ. A mouse model for inducible overexpression of Prdm14 results in rapid-onset and highly penetrant T-cell acute lymphoblastic leukemia (T-ALL). Dis Model Mech 2013; 6:1494-506. [PMID: 24046360 PMCID: PMC3820272 DOI: 10.1242/dmm.012575] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 08/30/2013] [Indexed: 01/02/2023] Open
Abstract
PRDM14 functions in embryonic stem cell (ESC) maintenance to promote the expression of pluripotency-associated genes while suppressing differentiation genes. Expression of PRDM14 is tightly regulated and typically limited to ESCs and primordial germ cells; however, aberrant expression is associated with tumor initiation in a wide variety of human cancers, including breast cancer and leukemia. Here, we describe the generation of a Cre-recombinase-inducible mouse model for the spatial and temporal control of Prdm14 misexpression [ROSA26 floxed-stop Prdm14 (R26PR)]. When R26PR is mated to either of two Cre lines, Mx1-cre or MMTV-cre, mice develop early-onset T-cell acute lymphoblastic leukemia (T-ALL) with median overall survival of 41 and 64 days for R26PR;Mx1-cre and R26PR;MMTV-cre, respectively. T-ALL is characterized by the accumulation of immature single-positive CD8 cells and their widespread infiltration. Leukemia is preceded by a dramatic expansion of cells resembling hematopoietic stem cells and lymphoid-committed progenitors prior to disease onset, accompanied by a blockage in B-cell differentiation at the early pro-B stage. Rapid-onset PRDM14-induced T-ALL requires factors that are present in stem and progenitor cells: R26PR;dLck-cre animals, which express Prdm14 starting at the double-positive stage of thymocyte development, do not develop disease. PRDM14-induced leukemic cells contain high levels of activated NOTCH1 and downstream NOTCH1 targets, including MYC and HES1, and are sensitive to pharmacological inhibition of NOTCH1 with the γ-secretase inhibitor DAPT. Greater than 50% of human T-ALLs harbor activating mutations in NOTCH1; thus, our model carries clinically relevant molecular aberrations. The penetrance, short latency and involvement of the NOTCH1 pathway will make this hematopoietic R26PR mouse model ideal for future studies on disease initiation, relapse and novel therapeutic drug combinations. Furthermore, breeding R26PR to additional Cre lines will allow for the continued development of novel cancer models.
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Affiliation(s)
- Brandi L. Carofino
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Bernard Ayanga
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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28
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Disruption of the CREBBP gene and decreased expression of CREB, NFκB p65, c-JUN, c-FOS, BCL2 and c-MYC suggest immune dysregulation. Hum Immunol 2013; 74:911-5. [PMID: 23643710 DOI: 10.1016/j.humimm.2013.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 03/23/2013] [Accepted: 04/10/2013] [Indexed: 02/08/2023]
Abstract
Genomic aberrations in the CREBBP (CREB-binding protein - CREBBP or CBP) gene such as point mutations, small insertions or exonic copy number changes are usually associated with Rubinstein-Taybi syndrome (RTs). In this study, the disruption of the CREBBP gene on chromosome 16p13.3, as revealed by CGH-array and FISH, suggests immune dysregulation in a patient with the Rubinstein Taybi syndrome (RTs) phenotype. Further investigation with Western blot techniques demonstrated decreased expression of CREB, NFκB, c-Jun, c-Fos, BCL2 and cMyc in peripheral blood mononuclear cells, thus indicating that the CREBBP gene is essential for the normal expression of these proteins and the regulation of immune responses.
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29
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c-Myc and E2F1 drive PBK/TOPK expression in high-grade malignant lymphomas. Leuk Res 2012; 37:447-54. [PMID: 23237560 DOI: 10.1016/j.leukres.2012.11.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 11/11/2012] [Accepted: 11/14/2012] [Indexed: 01/15/2023]
Abstract
c-Myc has been implicated in a variety of hematologic malignancies including Burkitt's lymphoma. Targeting c-Myc driven growth pathways could be therapeutically useful but might require the identification of critical downstream proteins. Here we show that the serine-threonine kinase PBK/TOPK is frequently overexpressed in high-grade lymphomas and its expression is positively correlated to that of c-Myc and E2F1. Further we demonstrate that c-Myc regulates PBK expression through E2F1. Additionally, inhibition of c-Myc, E2F1 or PBK comparably decreased cell growth and survival. In conclusion, a c-Myc-E2F1-PBK signaling pathway operates in high-grade lymphomas and may provide a useful target for novel antineoplastic therapeutics.
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30
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Delgado MD, Albajar M, Gomez-Casares MT, Batlle A, León J. MYC oncogene in myeloid neoplasias. Clin Transl Oncol 2012; 15:87-94. [PMID: 22911553 DOI: 10.1007/s12094-012-0926-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 07/24/2012] [Indexed: 01/13/2023]
Abstract
MYC is a transcription factor that regulates many critical genes for cell proliferation, differentiation, and biomass accumulation. MYC is one of the most prevalent oncogenes found to be altered in human cancer, being deregulated in about 50 % of tumors. Although MYC deregulation has been more frequently associated to lymphoma and lymphoblastic leukemia than to myeloid malignancies, a body of evidence has been gathered showing that MYC plays a relevant role in malignancies derived from the myeloid compartment. The myeloid leukemogenic activity of MYC has been demonstrated in different murine models. Not surprisingly, MYC has been found to be amplified or/and deregulated in the three major types of myeloid neoplasms: acute myeloid leukemia, myelodysplastic syndromes, and myeloproliferative neoplasms, including chronic myeloid leukemia. Here, we review the recent literature describing the involvement of MYC in myeloid tumors.
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Affiliation(s)
- M Dolores Delgado
- Group of Transcriptional Control and Cancer, Departamento de Biología Molecular, Facultad de Medicina, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria, CSIC, SODERCAN, Avda Cardenal Herrera Oria s/n, 39011, Santander, Spain
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31
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Qi CF, Kim YS, Xiang S, Abdullaev Z, Torrey TA, Janz S, Kovalchuk AL, Sun J, Chen D, Cho WC, Gu W, Morse HC. Characterization of ARF-BP1/HUWE1 interactions with CTCF, MYC, ARF and p53 in MYC-driven B cell neoplasms. Int J Mol Sci 2012; 13:6204-6219. [PMID: 22754359 PMCID: PMC3382761 DOI: 10.3390/ijms13056204] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 04/24/2012] [Accepted: 05/09/2012] [Indexed: 01/09/2023] Open
Abstract
Transcriptional activation of MYC is a hallmark of many B cell lineage neoplasms. MYC provides a constitutive proliferative signal but can also initiate ARF-dependent activation of p53 and apoptosis. The E3 ubiquitin ligase, ARF-BP1, encoded by HUWE1, modulates the activity of both the MYC and the ARF-p53 signaling pathways, prompting us to determine if it is involved in the pathogenesis of MYC-driven B cell lymphomas. ARF-BP1 was expressed at high levels in cell lines from lymphomas with either wild type or mutated p53 but not in ARF-deficient cells. Downregulation of ARF-BP1 resulted in elevated steady state levels of p53, growth arrest and apoptosis. Co-immunoprecipitation studies identified a multiprotein complex comprised of ARF-BP1, ARF, p53, MYC and the multifunctional DNA-binding factor, CTCF, which is involved in the transcriptional regulation of MYC, p53 and ARF. ARF-BP1 bound and ubiquitylated CTCF leading to its proteasomal degradation. ARF-BP1 and CTCF thus appear to be key cofactors linking the MYC proliferative and p53-ARF apoptotic pathways. In addition, ARF-BP1 could be a therapeutic target for MYC-driven B lineage neoplasms, even if p53 is inactive, with inhibition reducing the transcriptional activity of MYC for its target genes and stabilizing the apoptosis-promoting activities of p53.
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Affiliation(s)
- Chen-Feng Qi
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
- Authors to whom correspondence should be addressed; E-Mails: (C.-F.Q.); (H.C.M.); Tel.: +1-301-402-2698 (C.-F.Q.); +1-301-496-6379 (H.C.M.); Fax: +1-301-402-0077 (H.C.M.; C.-F.Q.)
| | - Yong-Soo Kim
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
| | - Shao Xiang
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Ziedulla Abdullaev
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
| | - Ted A. Torrey
- Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; E-Mail:
| | - Siegfried Janz
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; E-Mail:
| | - Alexander L. Kovalchuk
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
| | - Jiafang Sun
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
| | - Delin Chen
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; E-Mails: (D.C.); (W.G.)
| | - William C. Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong, China; E-Mail:
| | - Wei Gu
- Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; E-Mails: (D.C.); (W.G.)
| | - Herbert C. Morse
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; E-Mails: (Y.-S.K.); (S.X.); (Z.A.); (A.L.K.); (J.S.)
- Authors to whom correspondence should be addressed; E-Mails: (C.-F.Q.); (H.C.M.); Tel.: +1-301-402-2698 (C.-F.Q.); +1-301-496-6379 (H.C.M.); Fax: +1-301-402-0077 (H.C.M.; C.-F.Q.)
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Högstrand K, Hejll E, Sander B, Rozell B, Larsson LG, Grandien A. Inhibition of the intrinsic but not the extrinsic apoptosis pathway accelerates and drives MYC-driven tumorigenesis towards acute myeloid leukemia. PLoS One 2012; 7:e31366. [PMID: 22393362 PMCID: PMC3290626 DOI: 10.1371/journal.pone.0031366] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 01/09/2012] [Indexed: 11/18/2022] Open
Abstract
Myc plays an important role in tumor development, including acute myeloid leukemia (AML). However, MYC is also a powerful inducer of apoptosis, which is one of the major failsafe programs to prevent cancer development. To clarify the relative importance of the extrinsic (death receptor-mediated) versus the intrinsic (mitochondrial) pathway of apoptosis in MYC-driven AML, we coexpressed MYC together with anti-apoptotic proteins of relevance for AML; BCL-X(L)/BCL-2 (inhibiting the intrinsic pathway) or FLIP(L) (inhibiting the extrinsic pathway), in hematopoietic stems cells (HSCs). Transplantation of HSCs expressing MYC into syngeneic recipient mice resulted in development of AML and T-cell lymphomas within 7-9 weeks as expected. Importantly, coexpression of MYC together with BCL-X(L)/BCL-2 resulted in strongly accelerated kinetics and favored tumor development towards aggressive AML. In contrast, coexpression of MYC and FLIP(L) did neither accelerate tumorigenesis nor change the ratio of AML versus T-cell lymphoma. However, a change in distribution of immature CD4(+)CD8(+) versus mature CD4(+) T-cell lymphoma was observed in MYC/FLIP(L) mice, possibly as a result of increased survival of the CD4+ population, but this did not significantly affect the outcome of the disease. In conclusion, our findings provide direct evidence that BCL-X(L) and BCL-2 but not FLIP(L) acts in synergy with MYC to drive AML development.
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Affiliation(s)
- Kari Högstrand
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Eduar Hejll
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Sander
- Divisions of Clinical Research Center and Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Björn Rozell
- Divisions of Clinical Research Center and Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Lars-Gunnar Larsson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Alf Grandien
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- * E-mail:
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Abstract
Hematopoiesis is a process capable of generating millions of cells every second, as distributed in many cell types. The process is regulated by a number of transcription factors that regulate the differentiation along the distinct lineages and dictate the genetic program that defines each mature phenotype. Myc was first discovered as the oncogene of avian leukemogenic retroviruses; it was later found translocated in human lymphoma. From then on, evidence accumulated showing that c-Myc is one of the transcription factors playing a major role in hematopoiesis. The study of genetically modified mice with overexpression or deletion of Myc has shown that c-Myc is required for the correct balance between self-renewal and differentiation of hematopoietic stem cells (HSCs). Enforced Myc expression in mice leads to reduced HSC pools owing to loss of self-renewal activity at the expense of increased proliferation of progenitor cells and differentiation. c-Myc deficiency consistently results in the accumulation of HSCs. Other models with conditional Myc deletion have demonstrated that different lineages of hematopoietic cells differ in their requirement for c-Myc to regulate their proliferation and differentiation. When transgenic mice overexpress c-Myc or N-Myc in mature cells from the lymphoid or myeloid lineages, the result is lymphoma or leukemia. In agreement, enforced expression of c-Myc blocks the differentiation in several leukemia-derived cell lines capable of differentiating in culture. Not surprising, MYC deregulation is recurrently found in many types of human lymphoma and leukemia. Whereas MYC is deregulated by translocation in Burkitt lymphoma and, less frequently, other types of lymphoma, MYC is frequently overexpressed in acute lymphoblastic and myeloid leukemia, through mechanisms unrelated to chromosomal translocation, and is often associated with disease progression.
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Affiliation(s)
- M Dolores Delgado
- Departamento de Biología Molecular, Facultad de Medicina and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
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Mechanistic insight into Myc stabilization in breast cancer involving aberrant Axin1 expression. Proc Natl Acad Sci U S A 2011; 109:2790-5. [PMID: 21808024 DOI: 10.1073/pnas.1100764108] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
High expression of the oncoprotein Myc has been linked to poor outcome in human tumors. Although MYC gene amplification and translocations have been observed, this can explain Myc overexpression in only a subset of human tumors. Myc expression is in part controlled by its protein stability, which can be regulated by phosphorylation at threonine 58 (T58) and serine 62 (S62). We now report that Myc protein stability is increased in a number of breast cancer cell lines and this correlates with increased phosphorylation at S62 and decreased phosphorylation at T58. Moreover, we find this same shift in phosphorylation in primary breast cancers. The signaling cascade that controls phosphorylation at T58 and S62 is coordinated by the scaffold protein Axin1. We therefore examined Axin1 in breast cancer and report decreased AXIN1 expression and a shift in the ratio of expression of two naturally occurring AXIN1 splice variants. We demonstrate that this contributes to increased Myc protein stability, altered phosphorylation at S62 and T58, and increased oncogenic activity of Myc in breast cancer. Thus, our results reveal an important mode of Myc activation in human breast cancer and a mechanism contributing to Myc deregulation involving unique insight into inactivation of the Axin1 tumor suppressor in breast cancer.
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Liddiard K, Burnett AK, Darley RL, Tonks A. RUNX1-ETO deregulates the proliferation and growth factor responsiveness of human hematopoietic progenitor cells downstream of the myeloid transcription factor, MYCT1. Leukemia 2011; 26:177-9. [PMID: 21799513 PMCID: PMC3613704 DOI: 10.1038/leu.2011.188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Albajar M, Gómez-Casares MT, Llorca J, Mauleon I, Vaqué JP, Acosta JC, Bermúdez A, Donato N, Delgado MD, León J. MYC in chronic myeloid leukemia: induction of aberrant DNA synthesis and association with poor response to imatinib. Mol Cancer Res 2011; 9:564-76. [PMID: 21460180 DOI: 10.1158/1541-7786.mcr-10-0356] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Untreated chronic myeloid leukemia (CML) progresses from chronic phase to blastic crisis (BC). Increased genomic instability, deregulated proliferation, and loss of differentiation appear associated to BC, but the molecular alterations underlying the progression of CML are poorly characterized. MYC oncogene is frequently deregulated in human cancer, often associated with tumor progression. Genomic instability and induction of aberrant DNA replication are described as effects of MYC. In this report, we studied MYC activities in CML cell lines with conditional MYC expression with and without exposure to imatinib, the front-line drug in CML therapy. In cells with conditional MYC expression, MYC did not rescue the proliferation arrest mediated by imatinib but provoked aberrant DNA synthesis and accumulation of cells with 4C content. We studied MYC mRNA expression in 66 CML patients at different phases of the disease, and we found that MYC expression was higher in CML patients at diagnosis than control bone marrows or in patients responding to imatinib. Further, high MYC levels at diagnosis correlated with a poor response to imatinib. MYC expression did not directly correlate with BCR-ABL levels in patients treated with imatinib. Overall our study suggests that, as in other tumor models, MYC-induced aberrant DNA synthesis in CML cells is consistent with MYC overexpression in untreated CML patients and nonresponding patients and supports a role for MYC in CML progression, possibly through promotion of genomic instability.
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Affiliation(s)
- Marta Albajar
- Departamento de Biología Molecular, Facultad de Medicina, Instituto de Biomedicina y Biotecnología de Cantabria, Avda Cardenal Herrera Oria s/n, 39011 Santander, Spain
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Wang C, Tai Y, Lisanti MP, Liao DJ. c-Myc induction of programmed cell death may contribute to carcinogenesis: a perspective inspired by several concepts of chemical carcinogenesis. Cancer Biol Ther 2011; 11:615-26. [PMID: 21278493 DOI: 10.4161/cbt.11.7.14688] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The c-Myc protein, encoded by c-myc gene, in its wild-type form can induce tumors with a high frequency and can induce massive programmed cell death (PCD) in most transgenic mouse models, with greater efficiency than other oncogenes. Evidence also indicates that c-Myc can cause proliferative inhibition, i.e. mitoinhibition. The c-Myc-induced PCD and mitoinhibition, which may be attributable to its inhibition of cyclin D1 and induction of p53, may impose a pressure of compensatory proliferation, i.e. regeneration, onto the initiated cells (cancer progenitor cells) that occur sporadically and are resistant to the mitoinhibition. The initiated cells can thus proliferate robustly and progress to a malignancy. This hypothetical thinking, i.e. the concurrent PCD and mitoinhibition induced by c-Myc can promote carcinogenesis, predicts that an optimal balance is achieved between cell death and ensuing regeneration during oncogenic transformation by c-Myc, which can better promote carcinogenesis. In this perspective, we summarize accumulating evidence and challenge the current model that oncoprotein induces carcinogenesis by promoting cellular proliferation and/or inhibiting PCD. Inspired by c-myc oncogene, we surmise that many tumor-suppressive or growth-inhibitory genes may also be able to promote carcinogenesis in a similar way, i.e. by inducing PCD and/or mitoinhibition of normal cells to create a need for compensatory proliferation that drives a robust replication of initiating cells.
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Affiliation(s)
- Chenguang Wang
- Department of Stem Cell and Regenerative Medicine, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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Wang X, Cunningham M, Zhang X, Tokarz S, Laraway B, Troxell M, Sears RC. Phosphorylation regulates c-Myc's oncogenic activity in the mammary gland. Cancer Res 2011; 71:925-36. [PMID: 21266350 DOI: 10.1158/0008-5472.can-10-1032] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Expression of the c-Myc oncoprotein is affected by conserved threonine 58 (T58) and serine 62 (S62) phosphorylation sites that help to regulate c-Myc protein stability, and altered ratios of T58 and S62 phosphorylation have been observed in human cancer. Here, we report the development of 3 unique c-myc knock-in mice that conditionally express either c-Myc(WT) or the c-Myc(T58A) or c-Myc(S62A) phosphorylation mutant from the constitutively active ROSA26 locus in response to Cre recombinase to study the role of these phosphorylation sites in vivo. Using a mammary-specific Cre model, we found that expression of c-Myc(WT) resulted in increased mammary gland density, but normal morphology and no tumors at the level expressed from the ROSA promoter. In contrast, c-Myc(T58A) expression yielded enhanced mammary gland density, hyperplastic foci, cellular dysplasia, and mammary carcinoma, associated with increased genomic instability and suppressed apoptosis relative to c-Myc(WT). Alternatively, c-Myc(S62A) expression reduced mammary gland density relative to control glands, and this was associated with increased genomic instability and normal apoptotic function. Our results indicate that specific activities of c-Myc are differentially affected by T58 and S62 phosphorylation. This model provides a robust platform to interrogate the role that these phosphorylation sites play in c-Myc function during development and tumorigenesis.
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Affiliation(s)
- Xiaoyan Wang
- Molecular and Medical Genetics Department, Oregon Health and Sciences University, Portland, Oregon, USA
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Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is a hematologic neoplasm characterized by malignant expansion of immature T cells. Activated NOTCH (Notch(IC)) and c-MYC expression are increased in a large percentage of human T-ALL tumors. Furthermore, c-MYC has been shown to be a NOTCH target gene. Although activating mutations of Notch have been found in human T-ALL tumors, there is little evidence that the c-MYC locus is altered in this neoplasm. It was previously demonstrated that Notch and c-Myc-regulated genes have a broadly overlapping profile, including genes involved in cell cycle progression and metabolism. Given that Notch and c-Myc appear to function similarly in T-ALL, we sought to determine whether these two oncogenes could substitute for each other in T-ALL tumors. Here we report that NOTCH(IC) is able to maintain T-ALL tumors formed in the presence of exogenous NOTCH(IC) and c-MYC when exogenous c-MYC expression is extinguished. In contrast, c-MYC is incapable of maintaining these tumors in the absence of NOTCH(IC). We propose that failure of c-MYC to maintain these tumors is the result of p53-mediated apoptosis. These results demonstrate that T-ALL maintenance is dependent on NOTCH(IC), but not c-MYC, demonstrating that NOTCH is oncogenic dominant in T-ALL tumors.
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40
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Jones L, Wei G, Sevcikova S, Phan V, Jain S, Shieh A, Wong JCY, Li M, Dubansky J, Maunakea ML, Ochoa R, Zhu G, Tennant TR, Shannon KM, Lowe SW, Le Beau MM, Kogan SC. Gain of MYC underlies recurrent trisomy of the MYC chromosome in acute promyelocytic leukemia. ACTA ACUST UNITED AC 2010; 207:2581-94. [PMID: 21059853 PMCID: PMC2989761 DOI: 10.1084/jem.20091071] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The leukemogenic effects of Myc drive recurrent trisomy in a mouse model of acute myeloid leukemia. Gain of chromosome 8 is the most common chromosomal gain in human acute myeloid leukemia (AML). It has been hypothesized that gain of the MYC protooncogene is of central importance in trisomy 8, but the experimental data to support this are limited and controversial. In a mouse model of promyelocytic leukemia in which the MRP8 promoter drives expression of the PML-RARA fusion gene in myeloid cells, a Myc allele is gained in approximately two-thirds of cases as a result of trisomy for mouse chromosome 15. We used this model to test the idea that MYC underlies acquisition of trisomy in AML. We used a retroviral vector to drive expression of wild-type, hypermorphic, or hypomorphic MYC in bone marrow that expressed the PML-RARA transgene. MYC retroviruses cooperated in myeloid leukemogenesis and suppressed gain of chromosome 15. When the PML-RARA transgene was expressed in a Myc haploinsufficient background, we observed selection for increased copies of the wild-type Myc allele concomitant with leukemic transformation. In addition, we found that human myeloid leukemias with trisomy 8 have increased MYC. These data show that gain of MYC can contribute to the pathogenic effect of the most common trisomy of human AML.
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Affiliation(s)
- Letetia Jones
- Helen Diller Family Comprehensive Cancer Center and Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
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41
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Abstract
Up to 70% of all human malignancies show elevated expression of MYC. MYC is a pleiotropic transcription factor involved in many aspects of cellular development and physiology. Besides direct regulation of target genes involved in proliferation and growth MYC is implicated in controlling the complex networks of microRNAs and apoptosis mediators. The mode of MYC deregulation varies between different tumor entities. In most types of cancer high MYC levels are secondary to alterations in cell signalling pathways, leading to enhanced proliferation of the transformed cells. In some haematological malignancies, like Burkitt lymphoma (BL) and subsets of diffuse large B-cell lymphomas, elevated MYC levels are a direct consequence of genomic aberrations involving the MYC locus. BL is considered the prime example for MYC-induced lymphomagenesis. In comparison to other haematological malignancies it has the highest MYC-expression and is often connected to Epstein-Barr virus (EBV) infection. Over the past five decades BL has provided an invaluable tool for the entire discipline of oncology, helping to decipher many aspects of tumor biology. This review summarizes recent advances in the research on MYC-induced lymphomagenesis, focusing on the regulation of microRNAs and apoptosis, and possible contributions of EBV for lymphoma development.
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Affiliation(s)
- Kay Klapproth
- Institute of Physiological Chemistry, University of Ulm, Ulm, Germany
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42
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Induction of ectopic Myc target gene JAG2 augments hypoxic growth and tumorigenesis in a human B-cell model. Proc Natl Acad Sci U S A 2010; 107:3534-9. [PMID: 20133585 DOI: 10.1073/pnas.0901230107] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Ectopic Myc expression plays a key role in human tumorigenesis, and Myc dose-dependent tumorigenesis has been well established in transgenic mice, but the Myc target genes that are dependent on Myc levels have not been well characterized. In this regard, we used the human P493-6 B cells, which have a preneoplastic state dependent on the Epstein-Barr viral EBNA2 protein and a neoplastic state with ectopic inducible Myc, to identify putative ectopic Myc target genes. Among the ectopic targets, JAG2 that encodes a Notch receptor ligand Jagged2, was directly induced by Myc. Inhibition of Notch signaling through RNAi targeting JAG2 or the gamma-secretase Notch inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-(S)-phenylglycine t-butyl ester (DAPT) preferentially inhibited the neoplastic state in vitro. Furthermore, P493-6 tumorigenesis was inhibited by DAPT in vivo. Ectopic expression of JAG2 did not enhance aerobic cell proliferation, but increased proliferation of hypoxic cells in vitro and significantly increased in vivo tumorigenesis. Furthermore, the expression of Jagged2 in P493-6 tumors often overlapped with regions of hypoxia. These observations suggest that Notch signaling downstream of Myc enables cells to adapt in the tumor hypoxic microenvironment.
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43
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Abstract
For the many patients with lymphoma that has relapsed after and/or has become refractory to existing treatments, the development of novel therapeutics is imperative. Investigation into intracellular processes that are dysregulated during lymphomagenesis has uncovered several new potential targets for anticancer agents. Although monoclonal antibodies and other immunotherapeutics have led to dramatic advances in the treatment of patients with lymphoma, the parallel development of small molecule inhibitors has been equally exciting. These agents, whose small size allows direct entry into tumor cells, can target distinct proteins or complexes, thereby disrupting molecular processes on which neoplastic cells depend for survival and growth. This review surveys the published literature on many of these new targeted molecules, focusing on some of the most promising agents for which phase 2 data currently exist. It also explores the potential for incorporating these agents into broader multidrug regimens.
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44
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Abstract
In recent years considerable progress has been made in the treatment of patients with B-cell non-Hodgkin lymphoma (NHL). Although responses can be achieved with combination chemotherapy regimens, a substantial proportion of patients are still not cured. In recent years, the knowledge of the cellular and molecular biology of distinct types of B-cell NHL have led to the development of a new class of drugs that specifically targets unique disease-specific pathways. This review will focus on novel therapies that are being developed for the treatment of B-cell NHL including those targeting the B-cell receptor signaling pathway, the proteasome, epigenetic lesions, novel anti-apoptotic drugs, new monoclonal antibodies and immunomodulatory drugs.
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Affiliation(s)
- Javier Briones
- Hematology Service, Hospital Santa Creu i Sant Pau, Mas Casanovas 90, 4th floor, Room 2, 08040 Barcelona, Spain.
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45
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Comprehensive genomic screens identify a role for PLZF-RARalpha as a positive regulator of cell proliferation via direct regulation of c-MYC. Blood 2009; 114:5499-511. [PMID: 19855079 DOI: 10.1182/blood-2009-03-206524] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The t(11;17)(q23;q21) translocation is associated with a retinoic acid (RA)-insensitive form of acute promyelocytic leukemia (APL), involving the production of reciprocal fusion proteins, promyelocytic leukemia zinc finger-retinoic acid receptor alpha (PLZF-RARalpha) and RARalpha-PLZF. Using a combination of chromatin immunoprecipitation promotor arrays (ChIP-chip) and gene expression profiling, we identify novel, direct target genes of PLZF-RARalpha that tend to be repressed in APL compared with other myeloid leukemias, supporting the role of PLZF-RARalpha as an aberrant repressor in APL. In primary murine hematopoietic progenitors, PLZF-RARalpha promotes cell growth, and represses Dusp6 and Cdkn2d, while inducing c-Myc expression, consistent with its role in leukemogenesis. PLZF-RARalpha binds to a region of the c-MYC promoter overlapping a functional PLZF site and antagonizes PLZF-mediated repression, suggesting that PLZF-RARalpha may act as a dominant-negative version of PLZF by affecting the regulation of shared targets. RA induced the differentiation of PLZF-RARalpha-transformed murine hematopoietic cells and reduced the frequency of clonogenic progenitors, concomitant with c-Myc down-regulation. Surviving RA-treated cells retained the ability to be replated and this was associated with sustained c-Myc expression and repression of Dusp6, suggesting a role for these genes in maintaining a self-renewal pathway triggered by PLZF-RARalpha.
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46
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Thomas WD, Chen J, Gao YR, Cheung B, Koach J, Sekyere E, Norris MD, Haber M, Ellis T, Wainwright B, Marshall GM. Patched1 deletion increases N-Myc protein stability as a mechanism of medulloblastoma initiation and progression. Oncogene 2009; 28:1605-15. [PMID: 19234491 DOI: 10.1038/onc.2009.3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Medulloblastoma tumorigenesis caused by inactivating mutations in the PATCHED1 (PTCH1) gene is initiated by persistently activated Sonic Hedgehog (Shh) signaling in granule neuron precursors (GNPs) during the late stages of cerebellar development. Both normal cerebellar development and Shh-driven medulloblastoma tumorigenesis require N-Myc expression. However, the mechanisms by which N-Myc affects the stages of medulloblastoma initiation and progression are unknown. Here we used a mouse model of Ptch1 heterozygosity and medulloblastoma to show that increased N-Myc expression characterized the earliest selection of focal GNP hyperplasia destined for later tumor progression. Step-wise loss of Ptch1 expression, from tumor initiation to progression, led to incremental increases in N-Myc protein, rather than mRNA, expression. Increased N-Myc resulted in enhanced proliferation and death resistance of perinatal GNPs at tumor initiation. Sequential N-Myc protein phosphorylation at serine-62 and serine-62/threonine-58 characterized the early and late stages of medulloblastoma tumorigenesis, respectively. Shh pathway activation led to increased Myc protein stability and reduced expression of key regulatory factors. Taken together our data identify N-Myc protein stability as the result of loss of Ptch1, which distinguishes normal cerebellar development from medulloblastoma tumorigenesis.
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Affiliation(s)
- W D Thomas
- Children's Cancer Institute Australia for Medical Research, Randwick, New South Wales, Australia
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47
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Abstract
c-MYC inhibits differentiation and regulates the process by which cells acquire biomass, cell growth. Down-regulation of c-MYC, reduced cell growth, and decreased activity of the PI3K/AKT/mTORC1 signal transduction pathway are features of the terminal differentiation of committed myeloid precursors to polymorphonuclear neutrophils. Since mTORC1 regulates growth, we hypothesized that pharmacological inhibition of mTORC1 by rapamycin may reverse the phenotypic effects of c-MYC. Here we show that granulocytes blocked in their ability to differentiate by enforced expression of c-MYC can be induced to differentiate by reducing exogenous c-MYC expression through rapamycin treatment. Rapamycin also reduced expression of endogenous c-MYC and resulted in enhanced retinoid-induced differentiation. Total cellular c-Myc mRNA and c-MYC protein stability were unchanged by rapamycin, however the amount of c-Myc mRNA associated with polysomes was reduced. Therefore rapamycin limited expression of c-MYC by inhibiting c-Myc mRNA translation. These findings suggest that mTORC1 could be targeted to promote terminal differentiation in myeloid malignancies characterized by dysregulated expression of c-MYC.
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48
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van Hamburg JP, de Bruijn MJW, Dingjan GM, Beverloo HB, Diepstraten H, Ling KW, Hendriks RW. Cooperation of Gata3, c-Myc and Notch in malignant transformation of double positive thymocytes. Mol Immunol 2008; 45:3085-95. [PMID: 18471881 DOI: 10.1016/j.molimm.2008.03.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/07/2008] [Accepted: 03/10/2008] [Indexed: 12/16/2022]
Abstract
Gata transcription factors are critical regulators of proliferation and differentiation implicated in various human cancers, but specific genes activated by Gata proteins remain to be identified. We previously reported that enforced expression of Gata3 during T cell development in CD2-Gata3 transgenic mice induced CD4(+)CD8(+) double-positive (DP) T cell lymphoma. Here, we show that the presence of the DO11.10 T-cell receptor transgene, which directs DP cells towards the CD4 lineage, resulted in enhanced lymphoma development and a dramatic increase in thymocyte cell size in CD2-Gata3 transgenic mice. CD2-Gata3 DP cells expressed high levels of the proto-oncogene c-Myc but the Notch1 signaling pathway, which is known to induce c-Myc, was not activated. Gene expression profiling showed that in CD2-Gata3 lymphoma cells transcription of c-Myc and its target genes was further increased. A substantial fraction of CD2-Gata3 lymphomas had trisomy of chromosome 15, leading to an increased c-Myc gene dose. Interestingly, most lymphomas showed high expression of the Notch targets Deltex1 and Hes1, often due to activating Notch1 PEST domain mutations. Therefore, we conclude that enforced Gata3 expression converts DP thymocytes into a pre-malignant state, characterized by high c-Myc expression, whereby subsequent induction of Notch1 signaling cooperates to establish malignant transformation. The finding that Gata3 regulates c-Myc expression levels, in a direct or indirect fashion, may explain the parallel phenotypes of mice with overexpression or deficiency of either of the two transcription factors.
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49
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Abstract
MYC in human epidermal stem cells can stimulate differentiation rather than uncontrolled proliferation. This discovery was, understandably, greeted with scepticism by researchers. However, subsequent studies have confirmed that MYC can stimulate epidermal stem cells to differentiate and have shed light on the underlying mechanisms. Two concepts that are relevant to cancer have emerged: first, MYC regulates similar genes in different cell types, but the biological consequences are context-dependent; and second, MYC activation is not a simple 'on/off' switch - the cellular response depends on the strength and duration of MYC activity, which in turn is affected by the many cofactors and regulatory pathways with which MYC interacts.
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Affiliation(s)
- Fiona M Watt
- Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.
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50
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Abstract
The interaction of MYC and hypoxia inducible factors (HIFs) under physiological, non-tumorigenic conditions provides insights into normal homeostatic cellular responses to low oxygen levels (hypoxia). Many tumours contain genetic alterations, such as MYC activation, that can collaborate with HIF to confer metabolic advantages to tumour cells, which tend to exist in a hypoxic microenvironment. This Perspective emphasizes the differences between the transcriptional network that operates under normal homeostatic conditions and the network in a tumorigenic milieu.
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Affiliation(s)
- Chi V Dang
- Division of Hematology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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