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Forsythe SD, Pu T, Andrews SG, Madigan JP, Sadowski SM. Models in Pancreatic Neuroendocrine Neoplasms: Current Perspectives and Future Directions. Cancers (Basel) 2023; 15:3756. [PMID: 37568572 PMCID: PMC10416968 DOI: 10.3390/cancers15153756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
Pancreatic neuroendocrine neoplasms (pNENs) are a heterogeneous group of tumors derived from multiple neuroendocrine origin cell subtypes. Incidence rates for pNENs have steadily risen over the last decade, and outcomes continue to vary widely due to inability to properly screen. These tumors encompass a wide range of functional and non-functional subtypes, with their rarity and slow growth making therapeutic development difficult as most clinically used therapeutics are derived from retrospective analyses. Improved molecular understanding of these cancers has increased our knowledge of the tumor biology for pNENs. Despite these advances in our understanding of pNENs, there remains a dearth of models for further investigation. In this review, we will cover the current field of pNEN models, which include established cell lines, animal models such as mice and zebrafish, and three-dimensional (3D) cell models, and compare their uses in modeling various disease aspects. While no study model is a complete representation of pNEN biology, each has advantages which allow for new scientific understanding of these rare tumors. Future efforts and advancements in technology will continue to create new options in modeling these cancers.
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Affiliation(s)
- Steven D. Forsythe
- Neuroendocrine Cancer Therapy Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (S.D.F.); (S.G.A.); (J.P.M.)
| | - Tracey Pu
- Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Stephen G. Andrews
- Neuroendocrine Cancer Therapy Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (S.D.F.); (S.G.A.); (J.P.M.)
| | - James P. Madigan
- Neuroendocrine Cancer Therapy Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (S.D.F.); (S.G.A.); (J.P.M.)
| | - Samira M. Sadowski
- Neuroendocrine Cancer Therapy Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (S.D.F.); (S.G.A.); (J.P.M.)
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2
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Preclinical Models of Neuroendocrine Neoplasia. Cancers (Basel) 2022; 14:cancers14225646. [PMID: 36428741 PMCID: PMC9688518 DOI: 10.3390/cancers14225646] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/15/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022] Open
Abstract
Neuroendocrine neoplasia (NENs) are a complex and heterogeneous group of cancers that can arise from neuroendocrine tissues throughout the body and differentiate them from other tumors. Their low incidence and high diversity make many of them orphan conditions characterized by a low incidence and few dedicated clinical trials. Study of the molecular and genetic nature of these diseases is limited in comparison to more common cancers and more dependent on preclinical models, including both in vitro models (such as cell lines and 3D models) and in vivo models (such as patient derived xenografts (PDXs) and genetically-engineered mouse models (GEMMs)). While preclinical models do not fully recapitulate the nature of these cancers in patients, they are useful tools in investigation of the basic biology and early-stage investigation for evaluation of treatments for these cancers. We review available preclinical models for each type of NEN and discuss their history as well as their current use and translation.
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Detjen K, Hammerich L, Özdirik B, Demir M, Wiedenmann B, Tacke F, Jann H, Roderburg C. Models of Gastroenteropancreatic Neuroendocrine Neoplasms: Current Status and Future Directions. Neuroendocrinology 2021; 111:217-236. [PMID: 32615560 DOI: 10.1159/000509864] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/23/2020] [Indexed: 11/19/2022]
Abstract
Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare, heterogeneous group of tumors that originate from the endocrine system of the gastrointestinal tract and pancreas. GEP-NENs are subdivided according to their differentiation into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Since GEP-NENs represent rare diseases, only limited data from large prospective, randomized clinical trials are available, and recommendations for treatment of GEP-NEN are in part based on data from retrospective analyses or case series. In this context, tractable disease models that reflect the situation in humans and that allow to recapitulate the different clinical aspects and disease stages of GEP-NET or GEP-NEC are urgently needed. In this review, we highlight available data on mouse models for GEP-NEN. We discuss how these models reflect tumor biology of human disease and whether these models could serve as a tool for understanding the pathogenesis of GEP-NEN and for disease modeling and pharmacosensitivity assays, facilitating prediction of treatment response in patients. In addition, open issues applicable for future developments will be discussed.
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Affiliation(s)
- Katharina Detjen
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Linda Hammerich
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Burcin Özdirik
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Münevver Demir
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Bertram Wiedenmann
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Frank Tacke
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Henning Jann
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany
| | - Christoph Roderburg
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, Campus Virchow Klinikum and Charité Campus Mitte, Berlin, Germany,
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4
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Minervini G, Pennuto M, Tosatto SCE. The pVHL neglected functions, a tale of hypoxia-dependent and -independent regulations in cancer. Open Biol 2020; 10:200109. [PMID: 32603638 PMCID: PMC7574549 DOI: 10.1098/rsob.200109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The von Hippel–Lindau protein (pVHL) is a tumour suppressor mainly known for its role as master regulator of hypoxia-inducible factor (HIF) activity. Functional inactivation of pVHL is causative of the von Hippel–Lindau disease, an inherited predisposition to develop different cancers. Due to its impact on human health, pVHL has been widely studied in the last few decades. However, investigations mostly focus on its role in degrading HIFs, whereas alternative pVHL protein–protein interactions and functions are insistently surfacing in the literature. In this review, we analyse these almost neglected functions by dissecting specific conditions in which pVHL is proposed to have differential roles in promoting cancer. We reviewed its role in regulating phosphorylation as a number of works suggest pVHL to act as an inhibitor by either degrading or promoting downregulation of specific kinases. Further, we summarize hypoxia-dependent and -independent pVHL interactions with multiple protein partners and discuss their implications in tumorigenesis.
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Affiliation(s)
- Giovanni Minervini
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
| | - Maria Pennuto
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.,Veneto Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy
| | - Silvio C E Tosatto
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
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Abstract
Hypoxia inducible factors (HIFs) are critical regulators of the response to oxygen deficiency by activating target genes involved in a variety of biological functions. HIFs have been implicated in the pathophysiology of numerous pathologies including cancer. Patients with mutations in the von Hippel-Lindau (VHL) gene, an essential regulator of HIF activity, develop tumors in several organs including the pancreas. Previous functional studies of HIF activation in the pancreas have used Vhlh (the murine homolog of VHL) deficient mice. However, the role of each specific HIF transcription factors in the pancreas has not been thoroughly examined. We derived mice that constitutively express a normoxia-stable form of HIF2α in the pancreas. Activation of HIF2α in the pancreas severely impairs postnatal exocrine pancreas. Mice with pancreas-specific activation of HIF2α develop histological features reminiscent of pancreatitis including loss of acinar cells, ductal dilation and fibrosis. Moreover, we provide evidence that signaling pathways important for acinar cell homeostasis are altered in HIF2α-overexpressing pancreata.
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Stevenson M, Lines KE, Thakker RV. Molecular Genetic Studies of Pancreatic Neuroendocrine Tumors: New Therapeutic Approaches. Endocrinol Metab Clin North Am 2018; 47:525-548. [PMID: 30098714 PMCID: PMC7614857 DOI: 10.1016/j.ecl.2018.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pancreatic neuroendocrine tumors (PNETs) arise sporadically or as part of familial syndromes. Genetic studies of hereditary syndromes and whole exome sequencing analysis of sporadic NETs have revealed the roles of some genes involved in PNET tumorigenesis. The multiple endocrine neoplasia type 1 (MEN1) gene is most commonly mutated. Its encoded protein, menin, has roles in transcriptional regulation, genome stability, DNA repair, protein degradation, cell motility and adhesion, microRNA biogenesis, cell division, cell cycle control, and epigenetic regulation. Therapies targeting epigenetic regulation and MEN1 gene replacement have been reported to be effective in preclinical models.
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Affiliation(s)
- Mark Stevenson
- Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Churchill Hospital, Headington, Oxford OX3 7LJ, UK
| | - Kate E Lines
- Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Churchill Hospital, Headington, Oxford OX3 7LJ, UK
| | - Rajesh V Thakker
- Radcliffe Department of Medicine, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, Churchill Hospital, Headington, Oxford OX3 7LJ, UK.
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Wang H, Shepard MJ, Zhang C, Dong L, Walker D, Guedez L, Park S, Wang Y, Chen S, Pang Y, Zhang Q, Gao C, Wong WT, Wiley H, Pacak K, Chew EY, Zhuang Z, Chan CC. Deletion of the von Hippel-Lindau Gene in Hemangioblasts Causes Hemangioblastoma-like Lesions in Murine Retina. Cancer Res 2018; 78:1266-1274. [PMID: 29301791 PMCID: PMC7446935 DOI: 10.1158/0008-5472.can-17-1718] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/02/2017] [Accepted: 12/28/2017] [Indexed: 02/07/2023]
Abstract
von Hippel-Lindau (VHL) disease is an autosomal-dominant tumor predisposition syndrome characterized by the development of highly vascularized tumors and cysts. LOH of the VHL gene results in aberrant upregulation of hypoxia-inducible factors (HIF) and has been associated with tumor formation. Hemangioblastomas of the central nervous system and retina represent the most prevalent VHL-associated tumors, but no VHL animal model has reproduced retinal capillary hemangioblastomas (RCH), the hallmark lesion of ocular VHL. Here we report our work in developing a murine model of VHL-associated RCH by conditionally inactivating Vhl in a hemangioblast population using a Scl-Cre-ERT2 transgenic mouse line. In transgenic mice carrying the conditional allele and the Scl-Cre-ERT2 allele, 64% exhibited various retinal vascular anomalies following tamoxifen induction. Affected Vhl-mutant mice demonstrated retinal vascular lesions associated with prominent vasculature, anomalous capillary networks, hemorrhage, exudates, and localized fibrosis. Histologic analyses showed RCH-like lesions characterized by tortuous, dilated vasculature surrounded by "tumorlet" cell cluster and isolated foamy stromal cells, which are typically associated with RCH. Fluorescein angiography suggested increased vascular permeability of the irregular retinal vasculature and hemangioblastoma-like lesions. Vhl deletion was detected in "tumorlet" cells via microdissection. Our findings provide a phenotypic recapitulation of VHL-associated RCH in a murine model that may be useful to study RCH pathogenesis and therapeutics aimed at treating ocular VHL.Significance: This study describes a model that phenotypically recapitulates a form of retinal pathogenesis that is driven by genetic loss of the VHL tumor suppressor, providing a useful tool for its study and therapeutic intervention. Cancer Res; 78(5); 1266-74. ©2018 AACR.
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Affiliation(s)
- Herui Wang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | - Matthew J Shepard
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
- Department of Neurologic Surgery, University of Virginia Health System, Charlottesville, Virginia
| | - Chao Zhang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
- Department of Orthopedics, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Lijin Dong
- National Eye Institute, NIH, Bethesda, Maryland
| | - Dyvon Walker
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
| | | | | | - Yujuan Wang
- National Eye Institute, NIH, Bethesda, Maryland
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shida Chen
- National Eye Institute, NIH, Bethesda, Maryland
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ying Pang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | - Qi Zhang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Chun Gao
- National Eye Institute, NIH, Bethesda, Maryland
| | - Wai T Wong
- National Eye Institute, NIH, Bethesda, Maryland
| | - Henry Wiley
- National Eye Institute, NIH, Bethesda, Maryland
| | - Karel Pacak
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland
| | | | - Zhengping Zhuang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland.
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland
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8
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Abstract
With the current epidemic of diagnosed pancreatic cystic neoplasms on the rise, a substantial amount of work has been done to unravel their biology, thus leading to implications on clinical decision making. Recent genetic profiling of resected human specimens has identified alterations in signaling pathways involving KRAS and GNAS signaling as early events in the pathogenesis of intraductal pancreatic mucinous neoplasms. Progressively, mutations in genes such as TP53, SMAD4, RNF43, and others are thought to characterize invasive and advanced lesions. The role of inflammation in fueling the growth and transformation of these cysts has also begun to be studied with greater interest. A number of promising clinical studies have attempted to integrate these genetic insights into classifying these cysts and treating patients. We have reviewed existing literature on similar lines besides commenting on some useful animal models that recapitulate molecular and phenotypic progression of these cysts.
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9
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VHLdb: A database of von Hippel-Lindau protein interactors and mutations. Sci Rep 2016; 6:31128. [PMID: 27511743 PMCID: PMC4980628 DOI: 10.1038/srep31128] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 07/08/2016] [Indexed: 01/15/2023] Open
Abstract
Mutations in von Hippel-Lindau tumor suppressor protein (pVHL) predispose to develop
tumors affecting specific target organs, such as the retina, epididymis, adrenal
glands, pancreas and kidneys. Currently, more than 400 pVHL interacting
proteins are either described in the literature or predicted in public databases.
This data is scattered among several different sources, slowing down the
comprehension of pVHL’s biological role. Here we present VHLdb, a novel
database collecting available interaction and mutation data on pVHL to provide novel
integrated annotations. In VHLdb, pVHL interactors are organized according to two
annotation levels, manual and automatic. Mutation data are easily accessible and a
novel visualization tool has been implemented. A user-friendly feedback function to
improve database content through community-driven curation is also provided. VHLdb
presently contains 478 interactors, of which 117 have been manually curated, and
1,074 mutations. This makes it the largest available database for pVHL-related
information. VHLdb is available from URL: http://vhldb.bio.unipd.it/.
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10
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Yu R. Animal models of spontaneous pancreatic neuroendocrine tumors. Mol Cell Endocrinol 2016; 421:60-7. [PMID: 26261055 DOI: 10.1016/j.mce.2015.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 07/10/2015] [Accepted: 08/04/2015] [Indexed: 01/20/2023]
Abstract
Pancreatic neuroendocrine tumors (PNETs) are usually low-grade neoplasms derived from the endocrine pancreas. PNETs can be functioning and cause well-described hormonal hypersecretion syndromes or non-functioning and cause only tumor mass effect. PNETs appear to be more common recently likely due to incidental detection by imaging. Although the diagnosis and management of PNETs have been evolving rapidly, much remains to be studied in the areas of molecular pathogenesis, molecular markers of tumor behavior, early detection, and targeted drug therapy. Unique challenges facing PNETs studies are long disease course, the deep location of pancreas and difficult access to pancreatic tissue, and the variety of tumors, which make animal models valuable tools for PNETs studies. Existing animal models of PNETs have provided insights into the pathogenesis and natural history of human PNETs. Future studies on animal models of PNETs should address early tumor detection, molecular markers of tumor behavior, and novel targeted therapies.
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Affiliation(s)
- Run Yu
- Division of Endocrinology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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11
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García-Heredia JM, Felipe-Abrio B, Cano DA, Carnero A. Genetic modification of hypoxia signaling in animal models and its effect on cancer. Clin Transl Oncol 2014; 17:90-102. [PMID: 25351170 DOI: 10.1007/s12094-014-1236-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/24/2014] [Indexed: 12/19/2022]
Abstract
Conditions that cause hypoxemia or generalized tissue hypoxia, which can last for days, months, or even years, are very common in the human population and are among the leading causes of morbidity, disability, and mortality. Therefore, the molecular pathophysiology of hypoxia and its potential deleterious effects on human health are important issues at the forefront of biomedical research. Generalized hypoxia is a consequence of highly prevalent medical disorders that can severely reduce the capacity for O2 exchange between the air and pulmonary capillaries. In recent years, some of the key O2-dependent signaling pathways have been characterized at the molecular level. In particular, the prolyl hydroxylase (PHD)-hypoxia-inducible factor (HIF) cascade has emerged as the master regulator of a general gene expression program involved in cell/tissue/organ adaptation to hypoxia. Hypoxia has emerged as a critical factor in cancer because it can promote tumor initiation, progression, and resistance to therapy. Beyond its role in neovascularization as a mechanism of tumor adaptation to nutrient and O2 deprivation, hypoxia has been linked to prolonged cellular lifespan and immortalization, the generation of "oncometabolites", deregulation of stem cell proliferation, and inflammation, among other tumor hallmarks. Hypoxia may contribute to cancer through several independent pathways, the inter-connections of which have yet to be elucidated. Furthermore, the relevance of chronic hypoxemia in the initiation and progression of cancer has not been studied in depth in the whole organism. Therefore, we explore here the contributions of hypoxia to the whole organism by reviewing studies on genetically modified mice with alterations in the key molecular factors regulating hypoxia.
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Affiliation(s)
- J M García-Heredia
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, 41013, Seville, Spain
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12
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Lodh S, O’Hare EA, Zaghloul NA. Primary cilia in pancreatic development and disease. BIRTH DEFECTS RESEARCH. PART C, EMBRYO TODAY : REVIEWS 2014; 102:139-58. [PMID: 24864023 PMCID: PMC4213238 DOI: 10.1002/bdrc.21063] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/30/2014] [Accepted: 03/30/2014] [Indexed: 01/04/2023]
Abstract
Primary cilia and their anchoring basal bodies are important regulators of a growing list of signaling pathways. Consequently, dysfunction in proteins associated with these structures results in perturbation of the development and function of a spectrum of tissue and cell types. Here, we review the role of cilia in mediating the development and function of the pancreas. We focus on ciliary regulation of major pathways involved in pancreatic development, including Shh, Wnt, TGF-β, Notch, and fibroblast growth factor. We also discuss pancreatic phenotypes associated with ciliary dysfunction, including pancreatic cysts and defects in glucose homeostasis, and explore the potential role of cilia in such defects.
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Affiliation(s)
- Sukanya Lodh
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Elizabeth A. O’Hare
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Norann A. Zaghloul
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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13
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Robinson CM, Ohh M. The multifaceted von Hippel-Lindau tumour suppressor protein. FEBS Lett 2014; 588:2704-11. [PMID: 24583008 DOI: 10.1016/j.febslet.2014.02.026] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/14/2014] [Accepted: 02/17/2014] [Indexed: 11/26/2022]
Abstract
Loss of von Hippel-Lindau protein (pVHL) is known to contribute to the initiation and progression of tumours associated with VHL disease as well as certain sporadic tumours including clear cell renal cell carcinoma (ccRCC). The VHL gene was first identified and cloned over 20 years ago and our understanding of its functions and effects has significantly increased since then. The best-known function of pVHL is its role in promoting the degradation of hypoxia-inducible factor α subunit (HIFα) as part of an E3 ubiquitin ligase complex. HIF stabilisation and transcriptional activation are also associated with various epigenetic alterations, indicating a potential role for VHL loss with changes in the epigenome. This review will highlight current knowledge regarding pVHL as well as discuss potentially novel roles of pVHL and how these may impact on cancer progression.
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Affiliation(s)
- Claire M Robinson
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Michael Ohh
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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14
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Conditional deletion of p53 and Rb in the renin-expressing compartment of the pancreas leads to a highly penetrant metastatic pancreatic neuroendocrine carcinoma. Oncogene 2013; 33:5706-15. [PMID: 24292676 DOI: 10.1038/onc.2013.514] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 09/18/2013] [Accepted: 10/23/2013] [Indexed: 12/17/2022]
Abstract
Efforts to model human pancreatic neuroendocrine tumors (PanNETs) in animals have been moderately successful, with minimal evidence for glucagonomas or metastatic spread. The renin gene, although classically associated with expression in the kidney, is also expressed in many other extrarenal tissues including the pancreas. To induce tumorigenesis within rennin-specific tissues, floxed alleles of p53 and Rb were selectively abrogated using Cre-recombinase driven by the renin promoter. The primary neoplasm generated is a highly metastatic islet cell carcinoma of the pancreas. Lineage tracing identifies descendants of renin-expressing cells as pancreatic alpha cells despite a lack of active renin expression in the mature pancreas. Both primary and metastatic tumors express high levels of glucagon; furthermore, an increased level of glucagon is found in the serum, identifying the pancreatic cancer as a functional glucagonoma. This new model is highly penetrant and exhibits robust frequency of metastases to the lymph nodes and the liver, mimicking human disease, and provides a useful platform for better understanding pancreatic endocrine differentiation and development, as well as islet cell carcinogenesis. The use of fluorescent reporters for lineage tracing of the cells contributing to disease initiation and progression provides an unique opportunity to dissect the timeline of disease, examining mechanisms of the metastatic process, as well as recovering primary and metastatic cells for identifying cooperating mutations that are necessary for progression of disease.
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15
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Elimination of von Hippel-Lindau function perturbs pancreas endocrine homeostasis in mice. PLoS One 2013; 8:e72213. [PMID: 23977255 PMCID: PMC3748057 DOI: 10.1371/journal.pone.0072213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 07/08/2013] [Indexed: 12/23/2022] Open
Abstract
Mutations in the human homolog of the Vhlh gene [encoding the von-Hippel Lindau (VHL) protein] lead to tumor development. In mice, depletion of Vhlh in pancreatic ß-cells causes perturbed glucose homeostasis, but the role of this gene in other pancreatic cells is poorly understood. To investigate the function of VHL/HIF pathway in pancreatic cells, we inactivated Vhlh in the pancreatic epithelium as well as in the endocrine and exocrine lineages. Our results show that embryonic depletion of Vhlh within the pancreatic epithelium causes postnatal lethality due to severe hypoglycemia. The hypoglycemia is recapitulated in mice with endocrine-specific removal of Vhlh, while animals with loss of Vhlh predominantly in the exocrine compartment survive to adulthood with no overt defects in glucose metabolism. Mice with hypoglycemia display diminished insulin release in response to elevated glucose. Significantly, the glucagon response is impaired both in vivo (circulating glucagon levels) as well as in an in vitro secretion assay in isolated islets. Hypoxia also impairs glucagon secretion in a glucagon-expressing cell line in culture. Our results reveal a novel role for the hypoxia/HIF pathway in islet hormone secretion and maintenance of the fine balance that allows for the establishment of normoglycemia.
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Abstract
Pancreatic neuroendocrine tumors (PNETs), also known as islet cell tumors, are mostly indolent neoplasms that probably arise from a network of endocrine cells that includes islet cells and pluripotent precursors in the pancreatic ductal epithelium. The incidence and prevalence of PNETs continue to rise in recent years because of more sensitive detection. The molecular pathogenesis, early detection, molecular predictors of tumor behavior, and targeted drug therapy of PNETs are not well understood and require additional basic and translational research. The rarity and indolent nature of these tumors, difficulty of access to appropriate patient tissue samples, and varying histopathology and secreted hormones pose particular challenges to PNET researchers. Animal models and cell lines are indispensable tools for investigating the pathogenesis, pathophysiology, mechanisms for tumor invasion and metastasis, and therapeutics of PNETs. This review summarizes currently available animal models and cell lines of PNETs, which have provided valuable insights into the pathogenesis and natural history of human PNETs. In the future, animal models and cell lines of PNETs should also be used to study early tumor detection and molecular predictors of tumor behavior and to test the responses to, and mechanisms for, novel targeted drug therapies.
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Abstract
Cre/LoxP has broad utility for studying the function, development, and oncogenic transformation of pancreatic cells in mice. Here we provide an overview of the Cre driver lines that are available for such studies. We discuss how variegated expression, transgene silencing, and recombination in undesired cell types have conspired to limit the performance of these lines, sometimes leading to serious experimental concerns. We also discuss preferred strategies for achieving high-fidelity driver lines and remind investigators of the continuing need for caution when interpreting results obtained from any Cre/LoxP-based experiment performed in mice.
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Affiliation(s)
- Mark A Magnuson
- Center for Stem Cell Biology and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Pancreatic cyst development: insights from von Hippel-Lindau disease. Cilia 2013; 2:3. [PMID: 23384121 PMCID: PMC3579754 DOI: 10.1186/2046-2530-2-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/16/2013] [Indexed: 12/22/2022] Open
Abstract
Pancreatic cysts are a heterogeneous group of lesions, which can be benign or malignant. Due to improved imaging techniques, physicians are more often confronted with pancreatic cysts. Little is known about the origin of pancreatic cysts in general. Von Hippel-Lindau (VHL) disease is an atypical ciliopathy and inherited tumor syndrome, caused by a mutation in the VHL tumor suppressor gene encoding the VHL protein (pVHL). VHL patients are prone to develop cysts and neuroendocrine tumors in the pancreas in addition to several other benign and malignant neoplasms. Remarkably, pancreatic cysts occur in approximately 70% of VHL patients, making it the only hereditary tumor syndrome with such a discernible expression of pancreatic cysts. Cellular loss of pVHL due to biallelic mutation can model pancreatic cystogenesis in other organisms, suggesting a causal relationship. Here, we give a comprehensive overview of various pVHL functions, focusing on those that can potentially explain pancreatic cyst development in VHL disease. Based on preclinical studies, cilia loss in ductal cells is probably an important early event in pancreatic cyst development.
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19
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Park S, Chan CC. Von Hippel-Lindau disease (VHL): a need for a murine model with retinal hemangioblastoma. Histol Histopathol 2012; 27:975-84. [PMID: 22763871 PMCID: PMC3407271 DOI: 10.14670/hh-27.975] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Von Hippel-Lindau (VHL) disease is a highly penetrant autosomal dominant systemic malignancy that gives rise to cystic and highly vascularized tumors in a constellation of organs. Patients with VHL disease commonly present with hemangioblastomas in the central nervous system and the eye while other manifestations include pheochromocytoma, clear cell renal cell carcinoma, endolymphatic sac tumors of the middle ear, pancreatic cystadenomas, epididymal and broad ligament cystadenomas. Animal models inactivating the VHL gene product in various organ tissues have been constructed over the past 15 years to parse its HIF-associated mechanisms and its link to tumorigenesis. These models, despite advancing our understanding the molecular role of VHL, are by and large unable to recapitulate the more common features of human VHL disease. Up to date, no model exists that develop retinal hemangioblastomas, the most common clinical manifestation. The purpose of this review is: (1) to discuss the need for an ocular VHL model, (2) to review the animal models that recapitulate clinical VHL disease and (3) to propose potential mechanisms of tumorigenesis for the development of ocular VHL.
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Affiliation(s)
- Stanley Park
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Chi-Chao Chan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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20
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Richard S, Gardie B, Couvé S, Gad S. Von Hippel-Lindau: how a rare disease illuminates cancer biology. Semin Cancer Biol 2012; 23:26-37. [PMID: 22659535 DOI: 10.1016/j.semcancer.2012.05.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 05/22/2012] [Indexed: 12/19/2022]
Abstract
Von Hippel-Lindau (VHL) disease is a rare autosomal dominant syndrome (1/36,000 live births) with highly penetrance that predispose to the development of a panel of highly vascularized tumors (model of tumoral angiogenesis). Main manifestations include central nervous system (CNS) and retinal haemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), phaeochromocytomas and pancreatic neuroendocrine tumors. RCC has become the first potential cause of mortality and VHL disease is the main cause of inherited RCC. The disease is caused by germline mutations in the VHL tumor-suppressor gene that plays a major role in regulation of the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. VHL has also major HIF-independent functions, specially in regulation of primary cilium, extracellular matrix and apoptosis. Somatic inactivation of the VHL gene is the main molecular event in most sporadic RCC and the treatment of advanced RCC has been revolutionized by targeted therapy with drugs that block angiogenesis. These drugs are now in first line in metastatic sporadic RCC and have shown promising results for RCC, pancreatic neuroendocrine tumors and malignant pheochromocytomas in VHL patients.
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Affiliation(s)
- Stéphane Richard
- Laboratoire de Génétique Oncologique EPHE, INSERM U743, Faculté de Médecine Paris-Sud, 94276 Le Kremlin-Bicêtre et Institut de cancérologie Gustave Roussy, 94800 Villejuif, France.
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21
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Bader HL, Hsu T. Systemic VHL gene functions and the VHL disease. FEBS Lett 2012; 586:1562-9. [PMID: 22673568 DOI: 10.1016/j.febslet.2012.04.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 12/19/2022]
Abstract
The von Hippel-Lindau tumor suppressor gene (VHL) is best known as an E3 ubiquitin ligase that negatively regulates the hypoxia inducible factor (HIF). VHL mutations are the genetic defects underlying several human diseases including polycythemia, familial VHL tumor syndrome and sporadic renal cell carcinoma. VHL mutations can lead to cell-autonomous phenotypes in the tumor cells. However, non-tumor cell-autonomous functions of VHL have also been noted. VHL tumor-derived cytokines can promote inflammation and induce mobilization of endothelial progenitor cells. Up-regulation of HIF caused by VHL loss-of-function mutants, including heterozygotes, has been shown to increase the activities of hematopoietic stem cells, endothelial cells and myeloid cells. As such, systemic functions of VHL likely play important roles in the development of VHL disease.
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Affiliation(s)
- Hannah L Bader
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
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22
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Zhang J, Wang Y, Gao Z, Yun Z, Ye J. Hypoxia-inducible factor 1 activation from adipose protein 2-cre mediated knockout of von Hippel-Lindau gene leads to embryonic lethality. Clin Exp Pharmacol Physiol 2012; 39:145-50. [PMID: 22150821 PMCID: PMC3269514 DOI: 10.1111/j.1440-1681.2011.05656.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
von Hippel-Lindau protein, an E3 ubiquitin ligase from the von Hippel-Lindau (Vhl) gene, inhibits the transcriptional activity of hypoxia-inducible factor 1α in cells. To gain insight into the hypoxia-inducible factor 1α signalling pathway in adipose tissue, a study was conducted to generate fat-specific Vhl knockout mice. Cre-recombinase (Cre)/locus of crossover in P1(loxP) technology was used in the knockout study. The mice carrying floxed-Vhl alleles were crossed with adipose protein 2 (aP2)-Cre mice, in which the Cre gene is driven by the aP2 (fatty acid binding protein 4) gene promoter. The homozygous knockout mice exhibited embryonic lethality at E14.5-E18.5. The homozygous embryos suffered from haemorrhages in the brain and liver. Hypoxia-inducible factor 1α protein and its target gene protein, vascular endothelial growth factor, increased in the brain and liver. Endothelial proliferation and capillary leakage were observed in the tissues. Heterozygous knockout mice appeared normal in development, growth and reproductivity. β-galactosidase reporter mice were used in the analysis of tissue-specificity of Cre in aP2-Cre mice. Strong Cre activity was observed in the dorsal hindbrain region and vertebrae of E12.5 embryos. These results suggest that in the aP2-Cre mice, the recombinase activity is expressed in the central nervous system of the embryos. Central and peripheral haemorrhages are responsible for the embryonic lethality in the homozygous knockout mice.
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Affiliation(s)
- Jin Zhang
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Yanning Wang
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Zhanguo Gao
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
| | - Zhong Yun
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jianping Ye
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808
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23
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Wu J, Jiao Y, Dal Molin M, Maitra A, de Wilde RF, Wood LD, Eshleman JR, Goggins MG, Wolfgang CL, Canto MI, Schulick RD, Edil BH, Choti MA, Adsay V, Klimstra DS, Offerhaus GJA, Klein AP, Kopelovich L, Carter H, Karchin R, Allen PJ, Schmidt CM, Naito Y, Diaz LA, Kinzler KW, Papadopoulos N, Hruban RH, Vogelstein B. Whole-exome sequencing of neoplastic cysts of the pancreas reveals recurrent mutations in components of ubiquitin-dependent pathways. Proc Natl Acad Sci U S A 2011; 108:21188-93. [PMID: 22158988 PMCID: PMC3248495 DOI: 10.1073/pnas.1118046108] [Citation(s) in RCA: 458] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
More than 2% of adults harbor a pancreatic cyst, a subset of which progresses to invasive lesions with lethal consequences. To assess the genomic landscapes of neoplastic cysts of the pancreas, we determined the exomic sequences of DNA from the neoplastic epithelium of eight surgically resected cysts of each of the major neoplastic cyst types: serous cystadenomas (SCAs), intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs), and solid pseudopapillary neoplasms (SPNs). SPNs are low-grade malignancies, and IPMNs and MCNs, but not SCAs, have the capacity to progress to cancer. We found that SCAs, IPMNs, MCNs, and SPNs contained 10 ± 4.6, 27 ± 12, 16 ± 7.6, and 2.9 ± 2.1 somatic mutations per tumor, respectively. Among the mutations identified, E3 ubiquitin ligase components were of particular note. Four of the eight SCAs contained mutations of the von Hippel-Lindau gene (VHL), a key component of the VHL ubiquitin ligase complex that has previously been associated with renal cell carcinomas, SCAs, and other neoplasms. Six of the eight IPMNs and three of the eight MCNs harbored mutations of RNF43, a gene coding for a protein with intrinsic E3 ubiquitin ligase activity that has not previously been found to be genetically altered in any human cancer. The preponderance of inactivating mutations in RNF43 unequivocally establish it as a suppressor of both IPMNs and MCNs. SPNs contained remarkably few genetic alterations but always contained mutations of CTNNB1, previously demonstrated to inhibit degradation of the encoded protein (β-catenin) by E3 ubiquitin ligases. These results highlight the essential role of ubiquitin ligases in these neoplasms and have important implications for the diagnosis and treatment of patients with cystic tumors.
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Affiliation(s)
- Jian Wu
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
| | - Yuchen Jiao
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
| | | | | | | | | | | | | | - Christopher L. Wolfgang
- Surgery, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Medical Institutions, Baltimore, MD 21231
| | | | - Richard D. Schulick
- Surgery, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Medical Institutions, Baltimore, MD 21231
| | - Barish H. Edil
- Surgery, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Medical Institutions, Baltimore, MD 21231
| | - Michael A. Choti
- Surgery, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Medical Institutions, Baltimore, MD 21231
| | - Volkan Adsay
- Department of Pathology, Emory University, Atlanta, GA 30322
| | | | - G. Johan A. Offerhaus
- Department of Pathology, University Medical Center of Utrecht, 3508 GA Utrecht The Netherlands
| | | | - Levy Kopelovich
- Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Hannah Carter
- Department of Biomedical Engineering, Institute for Computational Medicine, The Johns Hopkins University, Baltimore, MD
| | - Rachel Karchin
- Department of Biomedical Engineering, Institute for Computational Medicine, The Johns Hopkins University, Baltimore, MD
| | - Peter J. Allen
- Surgery, Memorial Sloan–Kettering Cancer Center, New York, NY 10065
| | - C. Max Schmidt
- Departments of Surgery, Biochemistry, and Molecular Biology, Indiana University, Indianapolis, IN 46202; and
| | - Yoshiki Naito
- Department of Pathology, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Luis A. Diaz
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
| | - Kenneth W. Kinzler
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
| | - Nickolas Papadopoulos
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
| | | | - Bert Vogelstein
- Ludwig Center for Cancer Genetics and Howard Hughes Medical Institutions, Johns Hopkins Kimmel Cancer Center, Baltimore, MD 21231
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24
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Complex cellular functions of the von Hippel-Lindau tumor suppressor gene: insights from model organisms. Oncogene 2011; 31:2247-57. [PMID: 21996733 DOI: 10.1038/onc.2011.442] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The von Hippel-Lindau tumor suppressor gene (VHL) has attracted intensive interest not only because its mutations predispose carriers to devastating tumors, but also because it is involved in oxygen sensing under physiological conditions. VHL loss-of-function mutations result in organ-specific tumors, such as hemangioblastoma of the central nervous system and renal cell carcinoma, both untreatable with conventional chemotherapies. The VHL protein is best known as an E3 ubiquitin ligase that targets hypoxia-inducible factor-α (HIF-α), but many diverse, non-canonical cellular functions have also been assigned to VHL, mainly based on studies in cell culture systems. As such, although the HIF-dependent role of VHL is critical, the full spectrum of pathophysiological functions of VHL is still unresolved. Such understanding requires careful cross-referencing with physiologically relevant experimental models. Studies in model systems, such as Caenorhabditis elegans, Drosophila, zebrafish and mouse have provided critical in vivo confirmation of the VHL-HIF pathway, and verification of potentially important cellular functions including microtubule stabilization and epithelial morphogenesis. More recently, animal models have also suggested systemic roles of VHL in hematopoiesis, metabolic homeostasis and inflammation. In this review, the studies performed in model organisms will be summarized and placed in context with existing clinical and in vitro data.
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25
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Pascal LE, Ai J, Rigatti LH, Lipton AK, Xiao W, Gnarra JR, Wang Z. EAF2 loss enhances angiogenic effects of Von Hippel-Lindau heterozygosity on the murine liver and prostate. Angiogenesis 2011; 14:331-43. [PMID: 21638067 PMCID: PMC3155049 DOI: 10.1007/s10456-011-9217-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 05/10/2011] [Indexed: 12/21/2022]
Abstract
Von Hippel-Lindau (VHL) disease results from the inactivation of the VHL gene and is characterized by highly vascular tumors. A consequence of VHL loss is the stabilization of hypoxia-inducible factor (HIF) alpha subunits and increased expression of HIF target genes, which include pro-angiogenic growth factors such as vascular endothelial growth factor (VEGF). In mice, homozygous deletion of VHL is embryonic lethal due to vascular abnormalities in the placenta; and, VHL+/− mice develop proliferative vascular lesions in several major organs, most prominently the liver. Loss of ELL-associated factor (EAF2) in murine models has also been shown to induce increased vascular density in the liver as well as the prostate. Previously, EAF2 was determined to be a binding partner of VHL and loss of EAF2 induced a reduction in pVHL levels and an increase in hypoxia induced factor 1α (HIF1α) levels in vitro. Here we characterized the cooperative effects of VHL- and EAF2-deficiency on angiogenesis in the liver and prostate of male mice. VHL deficiency consistently increased the incidence of hepatic vascular lesions across three mouse strains. These vascular lesions where characterized by an increase in microvessel density, and staining intensity of VHL target proteins HIF1α and VEGF. EAF2−/−VHL+/− mice had increased incidence of proliferative hepatic vascular lesions (4/4) compared to VHL+/− (10/18) and EAF2−/− (0/5) mice. Prostates of EAF2−/−VHL+/− mice also displayed an increase in microvessel density, as well as stromal inflammation and prostatic intraepithelial neoplasia. These results suggest that cooperation of VHL and EAF2 may be critical for angiogenic regulation of the liver and prostate, and concurrent loss of these two tumor suppressors may result in a pro-angiogenic phenotype.
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Affiliation(s)
- Laura E Pascal
- Department of Urology, University of Pittsburgh School of Medicine, PA 15232, USA.
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26
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Abstract
Animal models of cancer have been instrumental in understanding the progression and therapy of hereditary cancer syndromes. The ability to alter the genome of an individual mouse cell in both constitutive and inducible approaches has led to many novel insights into their human counterparts. In this review, knockout mouse models of inherited human cancer syndromes are presented and insights from the study of these models are highlighted.
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Affiliation(s)
- Sohail Jahid
- Department of Biological Chemistry, University of California Irvine, Irvine, CA, USA
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27
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Choi D, Cai EP, Schroer SA, Wang L, Woo M. Vhl is required for normal pancreatic β cell function and the maintenance of β cell mass with age in mice. J Transl Med 2011; 91:527-38. [PMID: 21242957 DOI: 10.1038/labinvest.2010.207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Type 2 diabetes is hallmarked by insulin resistance and insufficient β-cell function. Islets of type 2 diabetes patients have been shown to have decreased hypoxia-inducible factor (HIF)-1α/β expression. Target genes of the HIF pathway are involved in angiogenesis, survival, proliferation, and energy metabolism, and von Hippel-Lindau protein (VHL) is a negative regulator of this pathway. We hypothesized that increased HIF-mediated gene transcription by VHL deletion in the β-cells would increase β-cell mass and function. We generated β-cell-specific VHL-knockout mice using the Cre-loxP recombination system driven by the rat insulin promoter to assess the role of VHL in glucose homeostasis and β-cell function. VHL deletion in the pancreatic β-cells led to impaired glucose tolerance due to defects in glucose-stimulated insulin secretion and β-cell mass with age. VHL-knockout islets had decreased GLUT2, but increased glucose transporter 1 and vascular endothelial growth factor expression. Furthermore, there were significant aberrations in islet morphology in the VHL-knockout mice, likely due to increased islet vasculature. Given that erythropoietin (EPO) is a target gene of the HIF pathway, which is not expressed in islets, we tested whether activating EPO signaling by systemic administration with recombinant human EPO (rHuEPO) can overcome the β-cell defects that occurred with VHL loss. We observed improved glucose tolerance and restoration of GLUT2 expression in VHL-deficient β-cells in response to rHuEPO. Contrary to our hypothesis, loss of VHL and increased transcription of HIF-target genes resulted in impaired β-cell function and mass, which can be overcome with exogenous EPO. Our results indicate a critical role for VHL in β-cell function and mass, and that EPO administration improved β-cell function making it a potential strategy for diabetes treatment.
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Affiliation(s)
- Diana Choi
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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28
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Abstract
β-cells sense glucose and secrete appropriate amounts of insulin by coupling glucose uptake and glycolysis with quantitative ATP production via mitochondrial oxidative pathways. Therefore, oxidative phosphorylation is essential for normal β-cell function. Multiple cell types adapt to hypoxia by inducing a transcriptional programme coordinated by the transcription factor hypoxia-inducible factor (HIF). HIF activity is regulated by the von Hippel-Lindau (Vhl) protein, which targets the HIFα subunit for proteasomal degradation in the presence of oxygen. Several recent studies have shown that Vhl deletion in β-cells results in Hif1α activation, impaired glucose-stimulated insulin secretion (GSIS) and glucose intolerance. This was found to be because of alterations in β-cell gene expression inducing a switch from aerobic glucose metabolism to anaerobic glycolysis, thus disrupting the GSIS triggering pathway. Situations in which islets may become hypoxic are discussed, in particular islet transplantation which has been reported to cause islet hypoxia because of an inadequate blood supply post-transplant. Aside from this principal role for HIF in negatively regulating β-cell glucose sensing, other aspects of hypoxia signalling are discussed including β-cell differentiation, development and vascularization. In conclusion, recent studies clearly show that hypoxia response mechanisms can negatively impact on glucose sensing mechanisms in the β-cell and this has the potential to impair β-cell function in a number of physiological and clinical situations.
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Affiliation(s)
- J Cantley
- Faculty of Medicine, Rayne Institute, University College London, London, UK.
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Shen HCJ, Ylaya K, Pechhold K, Wilson A, Adem A, Hewitt SM, Libutti SK. Multiple endocrine neoplasia type 1 deletion in pancreatic alpha-cells leads to development of insulinomas in mice. Endocrinology 2010; 151:4024-30. [PMID: 20555035 PMCID: PMC2940531 DOI: 10.1210/en.2009-1251] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The pancreatic alpha- and beta-cells are critical components in regulating blood glucose homeostasis via secretion of glucagon and insulin, respectively. Both cell types are typically localized in the islets of Langerhans. However, little is known about the roles of paracrine interactions that contribute to their physiological functions. The lack of suitable cell lines to study alpha- and beta-cells interactions have led us to develop an alpha-cell-specific Cre-expressing transgenic line utilizing a glucagon promoter sequence, the Glu-Cre transgenic mouse. Here, we demonstrate that the Glu-Cre could specifically and efficiently excise floxed target genes in adult islet alpha-cells. We further showed that deletion of the tumor suppressor gene, multiple endocrine neoplasia type 1 (Men1), in alpha-cells led to tumorigenesis. However, to our surprise, the lack of Men1 in alpha-cells did not result in glucagonomas but rather beta-cell insulinomas. Because deletion of the Men1 alleles was only present in alpha-cells, our data suggested that cross communication between alpha- and beta-cells contributes to tumorigenesis in the absence of Men1. Together, we believed that the new model systems described here will allow future studies to decipher cellular interactions between islet alpha- and beta-cells in a physiological context.
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Affiliation(s)
- H-C Jennifer Shen
- Tissue Array Research Program, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-8322, USA
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30
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Lombardi G, Zustovich F, Zovato S, Fiore D, Cappetta A, Pastorelli D. Characteristics and management of pancreatic lesions in Von Hippel-Lindau disease: a systematic literature review. Oncol Rev 2009. [DOI: 10.1007/s12156-009-0013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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