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Li Chew C, Lunardi A, Gulluni F, Ruan DT, Chen M, Salmena L, Nishino M, Papa A, Ng C, Fung J, Clohessy JG, Sasaki J, Sasaki T, Bronson RT, Hirsch E, Pandolfi PP. In Vivo Role of INPP4B in Tumor and Metastasis Suppression through Regulation of PI3K-AKT Signaling at Endosomes. Cancer Discov 2015; 5:740-51. [PMID: 25883022 DOI: 10.1158/2159-8290.cd-14-1347] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 04/01/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED The phosphatases PTEN and INPP4B have been proposed to act as tumor suppressors by antagonizing PI3K-AKT signaling and are frequently dysregulated in human cancer. Although PTEN has been extensively studied, little is known about the underlying mechanisms by which INPP4B exerts its tumor-suppressive function and its role in tumorigenesis in vivo. Here, we show that a partial or complete loss of Inpp4b morphs benign thyroid adenoma lesions in Pten heterozygous mice into lethal and metastatic follicular-like thyroid cancer (FTC). Importantly, analyses of human thyroid cancer cell lines and specimens reveal INPP4B downregulation in FTC. Mechanistically, we find that INPP4B, but not PTEN, is enriched in the early endosomes of thyroid cancer cells, where it selectively inhibits AKT2 activation and in turn tumor proliferation and anchorage-independent growth. We therefore identify INPP4B as a novel tumor suppressor in FTC oncogenesis and metastasis through localized regulation of the PI3K-AKT pathway at the endosomes. SIGNIFICANCE Although both PTEN and INPP4B can inhibit PI3K-AKT signaling through their lipid phosphatase activities, here we demonstrate lack of an epistatic relationship between the two tumor suppressors. Instead, the qualitative regulation of PI3K-AKT2 signaling by INPP4B provides a mechanism for their cooperation in suppressing thyroid tumorigenesis and metastasis.
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Linn DE, Bronson RT, Li Z. Genetic interaction between Tmprss2-ERG gene fusion and Nkx3.1-loss does not enhance prostate tumorigenesis in mouse models. PLoS One 2015; 10:e0120628. [PMID: 25780911 PMCID: PMC4364018 DOI: 10.1371/journal.pone.0120628] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/25/2015] [Indexed: 11/19/2022] Open
Abstract
Gene fusions involving ETS family transcription factors (mainly TMPRSS2-ERG and TMPRSS2-ETV1 fusions) have been found in ~50% of human prostate cancer cases. Although expression of TMPRSS2-ERG or TMPRSS2-ETV1 fusion alone is insufficient to initiate prostate tumorigenesis, they appear to sensitize prostate epithelial cells for cooperation with additional oncogenic mutations to drive frank prostate adenocarcinoma. To search for such ETS-cooperating oncogenic events, we focused on a well-studied prostate tumor suppressor NKX3.1, as loss of NKX3.1 is another common genetic alteration in human prostate cancer. Previous studies have shown that deletions at 8p21 (harboring NKX3.1) and 21q22 (resulting in TMPRSS2-ERG fusion) were both present in a subtype of prostate cancer cases, and that ERG can lead to epigenetic silencing of NKX3.1 in prostate cancer cells, whereas NKX3.1 can in turn negatively regulate TMPRSS2-ERG fusion expression via suppression of the TMPRSS2 promoter activity. We recently generated knockin mouse models for TMPRSS2-ERG and TMPRSS2-ETV1 fusions, utilizing the endogenous Tmprss2 promoter. We crossed these knockin models to an Nkx3.1 knockout mouse model. In Tmprss2-ERG;Nkx3.1+/- (or -/-) male mice, although we observed a slight but significant upregulation of Tmprss2-ERG fusion expression upon Nkx3.1 loss, we did not detect any significant cooperation between these two genetic events to enhance prostate tumorigenesis in vivo. Furthermore, retrospective analysis of a previously published human prostate cancer dataset revealed that within ERG-overexpressing prostate cancer cases, NKX3.1 loss or deletion did not predict biochemical relapse after radical prostatectomy. Collectively, these data suggest that although TMPRSS2-ERG fusion and loss of NKX3.1 are among the most common mutational events found in prostate cancer, and although each of them can sensitize prostate epithelial cells for cooperating with other oncogenic events, these two events themselves do not appear to cooperate at a significant level in vivo to enhance prostate tumorigenesis.
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Hettmer S, Bronson RT, Wagers AJ. Distinct malignant behaviors of mouse myogenic tumors induced by different oncogenetic lesions. Front Oncol 2015; 5:50. [PMID: 25759794 PMCID: PMC4338657 DOI: 10.3389/fonc.2015.00050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 02/11/2015] [Indexed: 02/06/2023] Open
Abstract
Rhabdomyosarcomas (RMS) are heterogeneous cancers with myogenic differentiation features. The cytogenetic and mutational aberrations in RMS are diverse. This study examined differences in the malignant behavior of two genetically distinct and disease-relevant mouse myogenic tumor models. Kras; p1619(null) myogenic tumors, initiated by expression of oncogenic Kras in p16p19(null) mouse satellite cells, were metastatic to the lungs of the majority of tumor-bearing animals and repopulated tumors in seven of nine secondary recipients. In contrast, SmoM2 tumors, initiated by ubiquitous expression of a mutant Smoothened allele, did not metastasize and repopulated tumors in 2 of 18 recipients only. In summary, genetically distinct myogenic tumors in mice exhibit marked differences in malignant behavior.
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104
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Lunardi A, Webster KA, Papa A, Padmani B, Clohessy JG, Bronson RT, Pandolfi PP. Role of aberrant PI3K pathway activation in gallbladder tumorigenesis. Oncotarget 2015; 5:894-900. [PMID: 24658595 PMCID: PMC4011591 DOI: 10.18632/oncotarget.1808] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The PI3K/AKT pathway governs a plethora of cellular processes, including cell growth, proliferation, and metabolism, in response to growth factors and cytokines. By acting as a unique lipid phosphatase converting phosphatidylinositol-3,4,5,-trisphosphate (PIP3) to phosphatidylinositol-4,5,-bisphosphate (PIP2), phosphatase and tensin homolog (PTEN) acts as the major cellular suppressor of PI3K signaling and AKT activation. Recently, PI3K mutations and loss/mutation of PTEN have been characterized in human gallbladder tumors; whether aberrant PTEN/PI3K pathway plays a causal role in gallbladder carcinogenesis, however, remains unknown. Herein we show that in mice, deregulation of PI3K/AKT signaling is sufficient to transform gallbladder epithelial cells and trigger fully penetrant, highly proliferative gallbladder tumors characterized by high levels of phospho-AKT. Histopathologically, these mouse tumors faithfully resemble human adenomatous gallbladder lesions. The identification of PI3K pathway deregulation as both an early event in the neoplastic transformation of the gallbladder epithelium and a main mechanism of tumor growth in Pten heterozygous and Pten mutant mouse models provides a new framework for studying in vivo the efficacy of target therapies directed against the PI3K pathway, as advanced metastatic tumors are often addicted to “trunkular” mutations.
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105
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Takahashi H, Jin C, Rajabi H, Pitroda S, Alam M, Ahmad R, Raina D, Hasegawa M, Suzuki Y, Tagde A, Bronson RT, Weichselbaum R, Kufe D. MUC1-C activates the TAK1 inflammatory pathway in colon cancer. Oncogene 2015; 34:5187-97. [PMID: 25659581 PMCID: PMC4530107 DOI: 10.1038/onc.2014.442] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/31/2014] [Accepted: 12/12/2014] [Indexed: 02/08/2023]
Abstract
The mucin 1 (MUC1) oncoprotein has been linked to the inflammatory response by promoting cytokine-mediated activation of the NF-κB pathway. The TGF-β-activated kinase 1 (TAK1) is an essential effector of proinflammatory NF-κB signaling that also regulates cancer cell survival. The present studies demonstrate that the MUC1-C transmembrane subunit induces TAK1 expression in colon cancer cells. MUC1 also induces TAK1 in a MUC1(+/-)/IL-10(-/-) mouse model of colitis and colon tumorigenesis. We show that MUC1-C promotes NF-κB-mediated activation of TAK1 transcription and, in a positive regulatory loop, MUC1-C contributes to TAK1-induced NF-κB signaling. In this way, MUC1-C binds directly to TAK1 and confers the association of TAK1 with TRAF6, which is necessary for TAK1-mediated activation of NF-κB. Targeting MUC1-C thus suppresses the TAK1NF-κB pathway, downregulates BCL-XL and in turn sensitizes colon cancer cells to MEK inhibition. Analysis of colon cancer databases further indicates that MUC1, TAK1 and TRAF6 are upregulated in tumors associated with decreased survival and that MUC1-C-induced gene expression patterns predict poor outcomes in patients. These results support a model in which MUC1-C-induced TAK1NF-κB signaling contributes to intestinal inflammation and colon cancer progression.
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106
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Guarnerio J, Riccardi L, Taulli R, Maeda T, Wang G, Hobbs RM, Song MS, Sportoletti P, Bernardi R, Bronson RT, Castillo-Martin M, Cordon-Cardo C, Lunardi A, Pandolfi PP. A genetic platform to model sarcomagenesis from primary adult mesenchymal stem cells. Cancer Discov 2015; 5:396-409. [PMID: 25614485 DOI: 10.1158/2159-8290.cd-14-1022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/14/2015] [Indexed: 01/07/2023]
Abstract
UNLABELLED The regulatory factors governing adult mesenchymal stem cell (MSC) physiology and their tumorigenic potential are still largely unknown, which substantially delays the identification of effective therapeutic approaches for the treatment of aggressive and lethal forms of MSC-derived mesenchymal tumors, such as undifferentiated sarcomas. Here, we have developed a novel platform to screen and quickly identify genes and pathways responsible for adult MSC transformation, modeled undifferentiated sarcoma in vivo, and, ultimately, tested the efficacy of targeting the identified oncopathways. Importantly, by taking advantage of this new platform, we demonstrate the key role of an aberrant LRF-DLK1-SOX9 pathway in the pathogenesis of undifferentiated sarcoma, with important therapeutic implications. SIGNIFICANCE The paucity of therapeutic options for the treatment of sarcoma calls for a rapid and effective preclinical assessment of new therapeutic modalities. We have here developed a new platform to deconstruct the molecular genetics underlying the pathogenesis of sarcoma and to evaluate in vivo the efficacy of novel targeted therapies.
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107
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Spurgeon ME, Cheng J, Bronson RT, Lambert PF, DeCaprio JA. Tumorigenic activity of merkel cell polyomavirus T antigens expressed in the stratified epithelium of mice. Cancer Res 2015; 75:1068-79. [PMID: 25596282 DOI: 10.1158/0008-5472.can-14-2425] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Merkel cell polyomavirus (MCPyV) is frequently associated with Merkel cell carcinoma (MCC), a highly aggressive neuroendocrine skin cancer. Most MCC tumors contain integrated copies of the viral genome with persistent expression of the MCPyV large T (LT) and small T (ST) antigen. MCPyV isolated from MCC typically contains wild-type ST but truncated forms of LT that retain the N-terminus but delete the C-terminus and render LT incapable of supporting virus replication. To determine the oncogenic activity of MCC tumor-derived T antigens in vivo, a conditional, tissue-specific mouse model was developed. Keratin 14-mediated Cre recombinase expression induced expression of MCPyV T antigens in stratified squamous epithelial cells and Merkel cells of the skin epidermis. Mice expressing MCPyV T antigens developed hyperplasia, hyperkeratosis, and acanthosis of the skin with additional abnormalities in whisker pads, footpads, and eyes. Nearly half of the mice also developed cutaneous papillomas. Evidence for neoplastic progression within stratified epithelia included increased cellular proliferation, unscheduled DNA synthesis, increased E2F-responsive genes levels, disrupted differentiation, and presence of a DNA damage response. These results indicate that MCPyV T antigens are tumorigenic in vivo, consistent with their suspected etiologic role in human cancer.
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108
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Leech JD, Lammers SHT, Goldman S, Auricchio N, Bronson RT, Kwiatkowski DJ, Sahin M. A vascular model of Tsc1 deficiency accelerates renal tumor formation with accompanying hemangiosarcomas. Mol Cancer Res 2014; 13:548-55. [PMID: 25548102 DOI: 10.1158/1541-7786.mcr-14-0178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
UNLABELLED Tuberous sclerosis complex (TSC) is an autosomal disease caused by inactivating mutations in either of the tumor suppressor genes TSC1 or TSC2. TSC-associated tumor growth is present in multiple tissues and organs including brain, kidney, liver, heart, lungs, and skin. In the kidney, TSC angiomyolipomas have aberrant vascular structures with abnormal endothelial cells, suggesting a role for endothelial mTORC1 function. In the current report, a genetically engineered mouse model (GEMM) with a conditional knockout allele of Tsc1 with a Darpp32-Cre allele displayed accelerated formation of both kidney cystadenomas and paw hemangiosarcomas. All mutant mice developed hemangiosarcomas on multiple paws by 6 weeks of age. By 16 weeks of age, the average mutant hind paw was 4.0 mm in diameter, nearly double the size of control mice. Furthermore, the hemangiosarcomas and kidney cystadenomas were responsive to intraperitoneal rapamycin treatment. Immunoblotting and immunostaining for phospho-S6 (pS6) and phospho-CAD showed that the effect of rapamycin on tumor size was through inhibition of the mTOR signaling pathway. Finally, elevated VEGF mRNA levels were also observed in hemangiosarcoma specimens. Because paw hemangiosarcomas are easily detectable and scorable for size and growth, this novel mouse model enables accelerated in vivo drug testing for therapies of TSC-related tumors. IMPLICATIONS These findings provide a strong rationale for simultaneous use of this conditional knockout mouse as an in vivo genetic model while seeking new cancer therapies for TSC-related tumors.
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109
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Sánchez-Rivera FJ, Papagiannakopoulos T, Romero R, Tammela T, Bauer MR, Bhutkar A, Joshi NS, Subbaraj L, Bronson RT, Xue W, Jacks T. Rapid modelling of cooperating genetic events in cancer through somatic genome editing. Nature 2014; 516:428-31. [PMID: 25337879 PMCID: PMC4292871 DOI: 10.1038/nature13906] [Citation(s) in RCA: 294] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/02/2014] [Indexed: 12/21/2022]
Abstract
Cancer is a multistep process that involves mutations and other alterations in oncogenes and tumour suppressor genes. Genome sequencing studies have identified a large collection of genetic alterations that occur in human cancers. However, the determination of which mutations are causally related to tumorigenesis remains a major challenge. Here we describe a novel CRISPR/Cas9-based approach for rapid functional investigation of candidate genes in well-established autochthonous mouse models of cancer. Using a Kras(G12D)-driven lung cancer model, we performed functional characterization of a panel of tumour suppressor genes with known loss-of-function alterations in human lung cancer. Cre-dependent somatic activation of oncogenic Kras(G12D) combined with CRISPR/Cas9-mediated genome editing of tumour suppressor genes resulted in lung adenocarcinomas with distinct histopathological and molecular features. This rapid somatic genome engineering approach enables functional characterization of putative cancer genes in the lung and other tissues using autochthonous mouse models. We anticipate that this approach can be used to systematically dissect the complex catalogue of mutations identified in cancer genome sequencing studies.
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110
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Akbay EA, Tchaicha JH, Altabef A, Mikse OR, Kikuchi E, Rhee K, Liao R, Bronson RT, Sholl LM, Meyerson M, Hammerman PS, Wong KK. Abstract 4851: Kinase domain activation of FGFR2 yields high-grade lung adenocarcinoma sensitive to a pan-FGFR inhibitor in a mouse model of NSCLC. Cancer Res 2014. [DOI: 10.1158/1538-7445.am2014-4851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Somatic mutations in Fibroblast Growth Factor Receptor 2 (FGFR2) have been found in 4-5% of patients diagnosed with non-small cell lung cancer (NSCLC). FGFR2 and other FGFR kinase family gene alterations have been found in lung squamous cell carcinoma, adenocarcinoma, and other malignancies though mouse models of FGFR driven lung cancers have not been reported. Here, we generated a genetically engineered mouse model (GEMM) of NSCLC driven by a kinase domain mutation in FGFR2. Combined with p53 ablation, primary grade III/IV adenocarcinoma was induced in the lung epithelial compartment exhibiting locally invasive and pleiotropic tendencies largely made up of multinucleated cells. Tumors were acutely sensitive to pharmacological inhibition of FGFR signaling. In preliminary studies tumors also responded to Programmed death pathway immune checkpoint blockade using anti-PD-1 antibody arguing for activated immune evasion mechanisms in this model.This is the first autochthonous FGFR2-driven lung cancer GEMM that can be applied across different cancer indications in a preclinical setting.
Citation Format: Esra A. Akbay, Jeremy H. Tchaicha, Abigail Altabef, Oliver R. Mikse, Eiki Kikuchi, Kevin Rhee, Rachel Liao, Roderick T. Bronson, Lynette M. Sholl, Matthew Meyerson, Peter S. Hammerman, Kwok-Kin Wong. Kinase domain activation of FGFR2 yields high-grade lung adenocarcinoma sensitive to a pan-FGFR inhibitor in a mouse model of NSCLC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4851. doi:10.1158/1538-7445.AM2014-4851
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111
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Castroneves LA, Jugo RH, Maynard MA, Lee JS, Wassner AJ, Dorfman D, Bronson RT, Ukomadu C, Agoston AT, Ding L, Luongo C, Guo C, Song H, Demchev V, Lee NY, Feldman HA, Vella KR, Peake RW, Hartigan C, Kellogg MD, Desai A, Salvatore D, Dentice M, Huang SA. Mice with hepatocyte-specific deficiency of type 3 deiodinase have intact liver regeneration and accelerated recovery from nonthyroidal illness after toxin-induced hepatonecrosis. Endocrinology 2014; 155:4061-8. [PMID: 25004090 PMCID: PMC4164928 DOI: 10.1210/en.2013-2028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Type 3 deiodinase (D3), the physiologic inactivator of thyroid hormones, is induced during tissue injury and regeneration. This has led to the hypotheses that D3 impacts injury tolerance by reducing local T3 signaling and contributes to the fall in serum triiodothyronine (T3) observed in up to 75% of sick patients (termed the low T3 syndrome). Here we show that a novel mutant mouse with hepatocyte-specific D3 deficiency has normal local responses to toxin-induced hepatonecrosis, including normal degrees of tissue necrosis and intact regeneration, but accelerated systemic recovery from illness-induced hypothyroxinemia and hypotriiodothyroninemia, demonstrating that peripheral D3 expression is a key modulator of the low T3 syndrome.
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112
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Fang X, Seim I, Huang Z, Gerashchenko MV, Xiong Z, Turanov AA, Zhu Y, Lobanov AV, Fan D, Yim SH, Yao X, Ma S, Yang L, Lee SG, Kim EB, Bronson RT, Šumbera R, Buffenstein R, Zhou X, Krogh A, Park TJ, Zhang G, Wang J, Gladyshev VN. Adaptations to a subterranean environment and longevity revealed by the analysis of mole rat genomes. Cell Rep 2014; 8:1354-64. [PMID: 25176646 PMCID: PMC4350764 DOI: 10.1016/j.celrep.2014.07.030] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 05/11/2014] [Accepted: 07/17/2014] [Indexed: 02/06/2023] Open
Abstract
Subterranean mammals spend their lives in dark, unventilated environments that are rich in carbon dioxide and ammonia and low in oxygen. Many of these animals are also long-lived and exhibit reduced aging-associated diseases, such as neurodegenerative disorders and cancer. We sequenced the genome of the Damaraland mole rat (DMR, Fukomys damarensis) and improved the genome assembly of the naked mole rat (NMR, Heterocephalus glaber). Comparative genome analyses, along with the transcriptomes of related subterranean rodents, revealed candidate molecular adaptations for subterranean life and longevity, including a divergent insulin peptide, expression of oxygen-carrying globins in the brain, prevention of high CO2-induced pain perception, and enhanced ammonia detoxification. Juxtaposition of the genomes of DMR and other more conventional animals with the genome of NMR revealed several truly exceptional NMR features: unusual thermogenesis, an aberrant melatonin system, pain insensitivity, and unique processing of 28S rRNA. Together, these genomes and transcriptomes extend our understanding of subterranean adaptations, stress resistance, and longevity.
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113
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Meira LB, Calvo JA, Shah D, Klapacz J, Moroski-Erkul CA, Bronson RT, Samson LD. Repair of endogenous DNA base lesions modulate lifespan in mice. DNA Repair (Amst) 2014; 21:78-86. [PMID: 24994062 PMCID: PMC4125484 DOI: 10.1016/j.dnarep.2014.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/30/2014] [Accepted: 05/20/2014] [Indexed: 12/21/2022]
Abstract
The accumulation of DNA damage is thought to contribute to the physiological decay associated with the aging process. Here, we report the results of a large-scale study examining longevity in various mouse models defective in the repair of DNA alkylation damage, or defective in the DNA damage response. We find that the repair of spontaneous DNA damage by alkyladenine DNA glycosylase (Aag/Mpg)-initiated base excision repair and O(6)-methylguanine DNA methyltransferase (Mgmt)-mediated direct reversal contributes to maximum life span in the laboratory mouse. We also uncovered important genetic interactions between Aag, which excises a wide variety of damaged DNA bases, and the DNA damage sensor and signaling protein, Atm. We show that Atm plays a role in mediating survival in the face of both spontaneous and induced DNA damage, and that Aag deficiency not only promotes overall survival, but also alters the tumor spectrum in Atm(-/-) mice. Further, the reversal of spontaneous alkylation damage by Mgmt interacts with the DNA mismatch repair pathway to modulate survival and tumor spectrum. Since these aging studies were performed without treatment with DNA damaging agents, our results indicate that the DNA damage that is generated endogenously accumulates with age, and that DNA alkylation repair proteins play a role in influencing longevity.
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114
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Jun HJ, Roy J, Smith TB, Wood LB, Lane K, Woolfenden S, Punko D, Bronson RT, Haigis KM, Breton S, Charest A. ROS1 signaling regulates epithelial differentiation in the epididymis. Endocrinology 2014; 155:3661-73. [PMID: 24971615 PMCID: PMC4138574 DOI: 10.1210/en.2014-1341] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The initial segment (IS) of the epididymis plays an essential role in male fertility. The IS epithelium is undifferentiated and nonfunctional at birth. Prior to puberty, the epithelium undergoes differentiation that leads to the formation of a fully functional organ. However, the mechanistic details of this program are not well understood. To explore this further, we used genetic engineering to create a kinase dead allele of the ROS1 receptor tyrosine kinase in mice and studied the effects of ROS1 tyrosine kinase activity on the differentiation of the IS epithelium. We show that the expression and activation of ROS1 coincides with the onset of differentiation and is exclusively located in the IS of the maturing and adult mouse epididymides. Here we demonstrate that the differentiation of the IS is dependent on the kinase activity of ROS1 and its downstream effector MEK1/2-ERK1/2 signaling axis. Using genetic engineering, we show that germ line ablation of ROS1 kinase activity leads to a failure of the IS epithelium to differentiate, and as a consequence sperm maturation and infertility were dramatically perturbed. Pharmacological inhibition of ROS1 kinase activity in the developing epididymis, however, only delayed differentiation transiently and did not result in infertility. Our results demonstrate that ROS1 kinase activity and the ensuing MEK1/2-ERK1/2 signaling are necessary for the postnatal development of the IS epithelium and that a sustained ablation of ROS1 kinase activity within the critical window of terminal differentiation abrogate the function of the epididymis and leads to sterility.
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115
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Chow KH, Shin DM, Jenkins MH, Miller EE, Shih DJ, Choi S, Low BE, Philip V, Rybinski B, Bronson RT, Taylor MD, Yun K. Epigenetic states of cells of origin and tumor evolution drive tumor-initiating cell phenotype and tumor heterogeneity. Cancer Res 2014; 74:4864-74. [PMID: 25136069 DOI: 10.1158/0008-5472.can-13-3293] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A central confounding factor in the development of targeted therapies is tumor cell heterogeneity, particularly in tumor-initiating cells (TIC), within clinically identical tumors. Here, we show how activation of the Sonic Hedgehog (SHH) pathway in neural stem and progenitor cells creates a foundation for tumor cell evolution to heterogeneous states that are histologically indistinguishable but molecularly distinct. In spontaneous medulloblastomas that arise in Patched (Ptch)(+/-) mice, we identified three distinct tumor subtypes. Through cell type-specific activation of the SHH pathway in vivo, we determined that different cells of origin evolved in unique ways to generate these subtypes. Moreover, TICs in each subtype had distinct molecular and cellular phenotypes. At the bulk tumor level, the three tumor subtypes could be distinguished by a 465-gene signature and by differential activation levels of the ERK and AKT pathways. Notably, TICs from different subtypes were differentially sensitive to SHH or AKT pathway inhibitors, highlighting new mechanisms of resistance to targeted therapies. In summary, our results show how evolutionary processes act on distinct cells of origin to contribute to tumoral heterogeneity, at both bulk tumor and TIC levels.
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116
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Lu G, Zhang Q, Huang Y, Song J, Tomaino R, Ehrenberger T, Lim E, Liu W, Bronson RT, Bowden M, Brock J, Krop IE, Dillon DA, Gygi SP, Mills GB, Richardson AL, Signoretti S, Yaffe MB, Kaelin WG. Phosphorylation of ETS1 by Src family kinases prevents its recognition by the COP1 tumor suppressor. Cancer Cell 2014; 26:222-34. [PMID: 25117710 PMCID: PMC4169234 DOI: 10.1016/j.ccr.2014.06.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 05/09/2014] [Accepted: 06/27/2014] [Indexed: 12/12/2022]
Abstract
Oncoproteins and tumor suppressors antagonistically converge on critical nodes governing neoplastic growth, invasion, and metastasis. We discovered that phosphorylation of the ETS1 and ETS2 transcriptional oncoproteins at specific serine or threonine residues creates binding sites for the COP1 tumor suppressor protein, which is an ubiquitin ligase component, leading to their destruction. In the case of ETS1, however, phosphorylation of a neighboring tyrosine residue by Src family kinases disrupts COP1 binding, thereby stabilizing ETS1. Src-dependent accumulation of ETS1 in breast cancer cells promotes anchorage-independent growth in vitro and tumor growth in vivo. These findings expand the list of potential COP1 substrates to include proteins whose COP1-binding sites are subject to regulatory phosphorylation and provide insights into transformation by Src family kinases.
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117
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Wan L, Hu G, Wei Y, Yuan M, Bronson RT, Yang Q, Siddiqui J, Pienta KJ, Kang Y. Genetic ablation of metadherin inhibits autochthonous prostate cancer progression and metastasis. Cancer Res 2014; 74:5336-47. [PMID: 25074613 DOI: 10.1158/0008-5472.can-14-1349] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Metadherin (MTDH) overexpression in diverse cancer types has been linked to poor clinical outcomes, but definitive genetic proof of its contributions to cancer remains incomplete. In particular, the degree to which MTDH may contribute to malignant progression in vivo is lacking. Here, we report that MTDH is amplified frequently in human prostate cancers where its expression levels are tightly correlated with prostate cancer progression and poor disease-free survival. Furthermore, we show that genetic ablation of MTDH in the transgenic adenomcarcinoma of mouse prostate (TRAMP) transgenic mouse model of prostate cancer blocks malignant progression without causing defects in the normal development of the prostate. Germline deletion of Mtdh in TRAMP mice prolonged tumor latency, reduced tumor burden, arrested progression of prostate cancer at well-differentiated stages, and inhibited systemic metastasis to distant organs, thereby decreasing cancer-related mortality ∼10-fold. Consistent with these findings, direct silencing of Mtdh in prostate cancer cells decreased proliferation in vitro and tumor growth in vivo, supporting an epithelial cell-intrinsic role of MTDH in prostate cancer. Together, our findings establish a pivotal role for MTDH in prostate cancer progression and metastasis and define MTDH as a therapeutic target in this setting. Cancer Res; 74(18); 5336-47. ©2014 AACR.
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118
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Tchaicha JH, Akbay EA, Altabef A, Mikse OR, Kikuchi E, Rhee K, Liao RG, Bronson RT, Sholl LM, Meyerson M, Hammerman PS, Wong KK. Kinase domain activation of FGFR2 yields high-grade lung adenocarcinoma sensitive to a Pan-FGFR inhibitor in a mouse model of NSCLC. Cancer Res 2014; 74:4676-84. [PMID: 25035393 DOI: 10.1158/0008-5472.can-13-3218] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Somatic mutations in FGFR2 are present in 4% to 5% of patients diagnosed with non-small cell lung cancer (NSCLC). Amplification and mutations in FGFR genes have been identified in patients with NSCLCs, and clinical trials are testing the efficacy of anti-FGFR therapies. FGFR2 and other FGFR kinase family gene alterations have been found in both lung squamous cell carcinoma and lung adenocarcinoma, although mouse models of FGFR-driven lung cancers have not been reported. Here, we generated a genetically engineered mouse model (GEMM) of NSCLC driven by a kinase domain mutation in FGFR2. Combined with p53 ablation, primary grade 3/4 adenocarcinoma was induced in the lung epithelial compartment exhibiting locally invasive and pleiotropic tendencies largely made up of multinucleated cells. Tumors were acutely sensitive to pan-FGFR inhibition. This is the first FGFR2-driven lung cancer GEMM, which can be applied across different cancer indications in a preclinical setting.
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MESH Headings
- Adenocarcinoma/drug therapy
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma of Lung
- Animals
- Animals, Genetically Modified/genetics
- Animals, Genetically Modified/metabolism
- Antineoplastic Agents/pharmacology
- Carcinoma, Non-Small-Cell Lung/drug therapy
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- Disease Models, Animal
- Female
- Humans
- Lung Neoplasms/drug therapy
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mutation/drug effects
- Mutation/genetics
- Protein Kinase Inhibitors/pharmacology
- Receptor, Fibroblast Growth Factor, Type 2/antagonists & inhibitors
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/metabolism
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
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119
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Wan L, Lu X, Yuan S, Wei Y, Guo F, Shen M, Yuan M, Chakrabarti R, Hua Y, Smith HA, Blanco MA, Chekmareva M, Wu H, Bronson RT, Haffty BG, Xing Y, Kang Y. MTDH-SND1 interaction is crucial for expansion and activity of tumor-initiating cells in diverse oncogene- and carcinogen-induced mammary tumors. Cancer Cell 2014; 26:92-105. [PMID: 24981741 PMCID: PMC4101059 DOI: 10.1016/j.ccr.2014.04.027] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/05/2014] [Accepted: 04/30/2014] [Indexed: 12/25/2022]
Abstract
The Metadherin gene (MTDH) is prevalently amplified in breast cancer and associated with poor prognosis; however, its functional contribution to tumorigenesis is poorly understood. Using mouse models representing different subtypes of breast cancer, we demonstrated that MTDH plays a critical role in mammary tumorigenesis by regulating oncogene-induced expansion and activities of tumor-initiating cells (TICs), whereas it is largely dispensable for normal development. Mechanistically, MTDH supports the survival of mammary epithelial cells under oncogenic/stress conditions by interacting with and stabilizing Staphylococcal nuclease domain-containing 1 (SND1). Silencing MTDH or SND1 individually or disrupting their interaction compromises tumorigenenic potential of TICs in vivo. This functional significance of MTDH-SND1 interaction is further supported by clinical analysis of human breast cancer samples.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene
- Animals
- Breast Neoplasms/chemically induced
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Breast Neoplasms/virology
- Cell Adhesion Molecules/metabolism
- Cell Line, Tumor
- Cell Proliferation
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cell Transformation, Viral
- Endonucleases
- Female
- Gene Expression Regulation, Neoplastic
- Genetic Predisposition to Disease
- HEK293 Cells
- Humans
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Animal/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/pathogenicity
- Medroxyprogesterone Acetate
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Neoplasm Invasiveness
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Phenotype
- Protein Binding
- RNA Interference
- RNA-Binding Proteins
- Time Factors
- Transfection
- Tumor Cells, Cultured
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120
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Li D, Ilnytskyy Y, Kovalchuk A, Khachigian LM, Bronson RT, Wang B, Kovalchuk O. Crucial role for early growth response-1 in the transcriptional regulation of miR-20b in breast cancer. Oncotarget 2014; 4:1373-87. [PMID: 23945289 PMCID: PMC3824527 DOI: 10.18632/oncotarget.1165] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Transcriptional regulation of miRNAs that control the pathogenesis of breast cancer remains largely unknown. Here, we showed that ionizing radiation, a known breast carcinogen, triggered the differential expression of miR-20b in mammary tissues. We identified several GC-rich consensus binding motifs for the zinc finger transcription factor early growth response-1 (EGR1) in miR-20b promoter. miR-20b was upregulated by IR and its upregulation correlated with EGR1 expression in the breast cancer cell line HCC1806. Therefore, we used HCC1806 cells as a model system to explore the role of EGR1 in miR-20b transcription. siRNA knockdown of EGR1 attenuated miR-20b expression. Luciferase assays showed that whereas EGR1 stimulated luciferase activity driven by the wild-type miR-20b promoter, this induction was abolished in the mutant miR-20 promoter construct. We noted significant enrichment of EGR1 at miR-20b promoter in HCC1806 cells compared with normal human mammary epithelial cells. Suppression of miR-20b significantly inhibited HCC1806 cell proliferation and migration, and led to G 0/G 1 and S phase arrest. In vitro RNA-pull down assays indicated that miR-20b targets numerous tumor suppressors, including PTEN and BRCA1, which were downregulated in HCC1806. Conversely, suppression of miR-20b increased PTEN and BRCA1 levels. Moreover, immunohistochemical and FISH analyses showed that the miR-20b expression correlated significantly with EGR1 levels in breast cancer tissues. Our findings thus demonstrate for the first time that EGR1 is a key player in the transcriptional control of miR-20b, and miR-20b may in turn function as an oncogene by contributing to breast tumorigenesis via tumor suppressor targeting.
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121
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Papa A, Wan L, Bonora M, Salmena L, Song MS, Hobbs RM, Lunardi A, Webster K, Ng C, Newton RH, Knoblauch N, Guarnerio J, Ito K, Turka LA, Beck AH, Pinton P, Bronson RT, Wei W, Pandolfi PP. Cancer-associated PTEN mutants act in a dominant-negative manner to suppress PTEN protein function. Cell 2014; 157:595-610. [PMID: 24766807 DOI: 10.1016/j.cell.2014.03.027] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 11/25/2013] [Accepted: 03/11/2014] [Indexed: 10/25/2022]
Abstract
PTEN dysfunction plays a crucial role in the pathogenesis of hereditary and sporadic cancers. Here, we show that PTEN homodimerizes and, in this active conformation, exerts lipid phosphatase activity on PtdIns(3,4,5)P3. We demonstrate that catalytically inactive cancer-associated PTEN mutants heterodimerize with wild-type PTEN and constrain its phosphatase activity in a dominant-negative manner. To study the consequences of homo- and heterodimerization of wild-type and mutant PTEN in vivo, we generated Pten knockin mice harboring two cancer-associated PTEN mutations (PtenC124S and PtenG129E). Heterozygous Pten(C124S/+) and Pten(G129E/+) cells and tissues exhibit increased sensitivity to PI3-K/Akt activation compared to wild-type and Pten(+/-) counterparts, whereas this difference is no longer apparent between Pten(C124S/-) and Pten(-/-) cells. Notably, Pten KI mice are more tumor prone and display features reminiscent of complete Pten loss. Our findings reveal that PTEN loss and PTEN mutations are not synonymous and define a working model for the function and regulation of PTEN.
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122
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Zhao T, Li Y, Bronson RT, Liu B, Velmahos GC, Alam HB. Selective histone deacetylase-6 inhibition attenuates stress responses and prevents immune organ atrophy in a lethal septic model. Surgery 2014; 156:235-42. [PMID: 24947640 DOI: 10.1016/j.surg.2014.03.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/19/2014] [Indexed: 01/28/2023]
Abstract
BACKGROUND An overproduction of corticosterone during severe sepsis results in increased apoptosis of immune cells, which may result in relative immunosuppression and an impaired ability to fight infections. We have previously demonstrated that administration of tubastatin A, a selective inhibitor of histone deacetylase-6 (HDAC6), improves survival in a lethal model of cecal ligation and puncture (CLP) in mice. The purpose of this study was to characterize the effects of this treatment on sepsis-induced stress responses and immune function. METHODS C57BL/6J mice were subjected to CLP, and 1 hour later given an intraperitoneal injection of either tubastatin A dissolved in dimethyl sulfoxide (DMSO), or DMSO only. Blood samples were collected to measure the levels of circulating corticosterone and adrenocorticotropic hormone (ACTH). Thymus and long bones (femur and tibia) were subjected to hematoxylin and eosin staining, and immunohistochemistry was utilized to detect cleaved-caspase 3 in the splenic follicles as a measure of cellular apoptosis. RESULTS All vehicle-treated CLP animals died within 3 days, and displayed increased corticosterone and decreased ACTH levels compared with the sham-operated group. These animals also developed atrophy of thymic cortex with a marked depletion of thymocytes. Tubastatin A treatment significantly attenuated the stress hormone abnormalities. Treated animals also had significantly lower percentages of thymic atrophy (95.0 ± 5.0 vs 42.5 ± 25.3; P = .0366), bone marrow depletion and atrophy (58.3 ± 6.5 vs 25.0 ± 14.4%; P = .0449), and cellular apoptosis in the splenic follicles (41.2 ± 3.7 vs 28.5 ± 4.3 per 40× field; P = .0354). CONCLUSION Selective inhibition of HDAC6 in this lethal septic model was associated with a significant blunting of the stress responses, with attenuated thymic and bone marrow atrophy, and decreased splenic apoptosis. Our findings identify a novel mechanism behind the survival advantage seen with tubastatin A treatment.
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123
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Park HJ, Hong M, Bronson RT, Israel MA, Frankel WN, Yun K. Elevated Id2 expression results in precocious neural stem cell depletion and abnormal brain development. Stem Cells 2014; 31:1010-21. [PMID: 23390122 DOI: 10.1002/stem.1351] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/15/2013] [Indexed: 11/06/2022]
Abstract
Id2 is a helix-loop-helix transcription factor essential for normal development, and its expression is dysregulated in many human neurological conditions. Although it is speculated that elevated Id2 levels contribute to the pathogenesis of these disorders, it is unknown whether dysregulated Id2 expression is sufficient to perturb normal brain development or function. Here, we show that mice with elevated Id2 expression during embryonic stages develop microcephaly, and that females in particular are prone to generalized tonic-clonic seizures. Analyses of Id2 transgenic brains indicate that Id2 activity is highly cell context specific: elevated Id2 expression in naive neural stem cells (NSCs) in early neuroepithelium induces apoptosis and loss of NSCs and intermediate progenitors. Activation of Id2 in maturing neuroepithelium results in less severe phenotypes and is accompanied by elevation of G1 cyclin expression and p53 target gene expression. In contrast, activation of Id2 in committed intermediate progenitors has no significant phenotype. Functional analysis with Id2-overexpressing and Id2-null NSCs shows that Id2 negatively regulates NSC self-renewal in vivo, in contrast to previous cell culture experiments. Deletion of p53 function from Id2-transgenic brains rescues apoptosis and results in increased incidence of brain tumors. Furthermore, Id2 overexpression normalizes the increased self-renewal of p53-null NSCs, suggesting that Id2 activates and modulates the p53 pathway in NSCs. Together, these data suggest that elevated Id2 expression in embryonic brains can cause deregulated NSC self-renewal, differentiation, and survival that manifest in multiple neurological outcomes in mature brains, including microcephaly, seizures, and brain tumors.
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124
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Akbay EA, Moslehi J, Christensen CL, Saha S, Tchaicha JH, Ramkissoon SH, Stewart KM, Carretero J, Kikuchi E, Zhang H, Cohoon TJ, Murray S, Liu W, Uno K, Fisch S, Jones K, Gurumurthy S, Gliser C, Choe S, Keenan M, Son J, Stanley I, Losman JA, Padera R, Bronson RT, Asara JM, Abdel-Wahab O, Amrein PC, Fathi AT, Danial NN, Kimmelman AC, Kung AL, Ligon KL, Yen KE, Kaelin WG, Bardeesy N, Wong KK. D-2-hydroxyglutarate produced by mutant IDH2 causes cardiomyopathy and neurodegeneration in mice. Genes Dev 2014; 28:479-90. [PMID: 24589777 PMCID: PMC3950345 DOI: 10.1101/gad.231233.113] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) have been discovered in several cancers, and these mutant enzymes exhibit neomorphic activity resulting in production of D2-hydroxyglutaric acid (D-2HG). Akbay et al. find that adult transgenic mice with conditionally activated IDH2R140Q and IDH2R172K alleles exhibit dilated cardiomyopathy and muscular dystrophy. These phenotypes were even more pronounced in embryos. Cardiac hypertrophy was also observed in nude mice implanted with IDH2R140Q-expressing xenografts. Silencing of IDH2R140Q in mice with an inducible transgene restored heart function by lowering 2HG levels. Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) have been discovered in several cancer types and cause the neurometabolic syndrome D2-hydroxyglutaric aciduria (D2HGA). The mutant enzymes exhibit neomorphic activity resulting in production of D2-hydroxyglutaric acid (D-2HG). To study the pathophysiological consequences of the accumulation of D-2HG, we generated transgenic mice with conditionally activated IDH2R140Q and IDH2R172K alleles. Global induction of mutant IDH2 expression in adults resulted in dilated cardiomyopathy, white matter abnormalities throughout the central nervous system (CNS), and muscular dystrophy. Embryonic activation of mutant IDH2 resulted in more pronounced phenotypes, including runting, hydrocephalus, and shortened life span, recapitulating the abnormalities observed in D2HGA patients. The diseased hearts exhibited mitochondrial damage and glycogen accumulation with a concordant up-regulation of genes involved in glycogen biosynthesis. Notably, mild cardiac hypertrophy was also observed in nude mice implanted with IDH2R140Q-expressing xenografts, suggesting that 2HG may potentially act in a paracrine fashion. Finally, we show that silencing of IDH2R140Q in mice with an inducible transgene restores heart function by lowering 2HG levels. Together, these findings indicate that inhibitors of mutant IDH2 may be beneficial in the treatment of D2HGA and suggest that 2HG produced by IDH mutant tumors has the potential to provoke a paraneoplastic condition.
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125
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Seim I, Fang X, Xiong Z, Lobanov AV, Huang Z, Ma S, Feng Y, Turanov AA, Zhu Y, Lenz TL, Gerashchenko MV, Fan D, Hee Yim S, Yao X, Jordan D, Xiong Y, Ma Y, Lyapunov AN, Chen G, Kulakova OI, Sun Y, Lee SG, Bronson RT, Moskalev AA, Sunyaev SR, Zhang G, Krogh A, Wang J, Gladyshev VN. Genome analysis reveals insights into physiology and longevity of the Brandt's bat Myotis brandtii. Nat Commun 2014; 4:2212. [PMID: 23962925 PMCID: PMC3753542 DOI: 10.1038/ncomms3212] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 06/26/2013] [Indexed: 11/20/2022] Open
Abstract
Bats account for one-fifth of mammalian species, are the only mammals with powered flight, and are among the few animals that echolocate. The insect-eating Brandt’s bat (Myotis brandtii) is the longest-lived bat species known to date (lifespan exceeds 40 years) and, at 4–8 g adult body weight, is the most extreme mammal with regard to disparity between body mass and longevity. Here we report sequencing and analysis of the Brandt’s bat genome and transcriptome, which suggest adaptations consistent with echolocation and hibernation, as well as altered metabolism, reproduction and visual function. Unique sequence changes in growth hormone and insulin-like growth factor 1 receptors are also observed. The data suggest that an altered growth hormone/insulin-like growth factor 1 axis, which may be common to other long-lived bat species, together with adaptations such as hibernation and low reproductive rate, contribute to the exceptional lifespan of the Brandt’s bat. Bats account for 20 per cent of all mammals, these are the only mammals with powered flight, and are among the few animals that echolocate. Here, Seim et al. sequence the genome of the long-lived (>40 years) Brandt’s bat, Myotis brandtii and provide clues to its evolution, longevity and other traits.
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