301
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Abstract
Germline inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene causes the von Hippel-Lindau hereditary cancer syndrome, and somatic mutations of this gene have been linked to the development of sporadic hemangioblastomas and clear-cell renal carcinomas. The VHL tumor suppressor protein (pVHL), through its oxygen-dependent polyubiquitylation of hypoxia-inducible factor (HIF), plays a central role in the mammalian oxygen-sensing pathway. This interaction between pVHL and HIF is governed by post-translational prolyl hydroxylation of HIF in the presence of oxygen by a conserved family of Egl-nine (EGLN) enzymes. In the absence of pVHL, HIF becomes stabilized and is free to induce the expression of its target genes, many of which are important in regulating angiogenesis, cell growth, or cell survival. Moreover, preliminary data indicate that HIF plays a critical role in pVHL-defective tumor formation, raising the possibility that drugs directed against HIF or its downstream targets (such as vascular endothelial growth factor) might one day play a role in the treatment of hemangioblastoma and renal cell carcinoma. On the other hand, clear genotype-phenotype correlations are emerging in VHL disease and can be rationalized if pVHL has functions separate from its control of HIF.
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Affiliation(s)
- William Y Kim
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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302
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Bracken CP, Whitelaw ML, Peet DJ. Activity of hypoxia-inducible factor 2alpha is regulated by association with the NF-kappaB essential modulator. J Biol Chem 2005; 280:14240-51. [PMID: 15653678 DOI: 10.1074/jbc.m409987200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hypoxia-inducible factors 1alpha (HIF-1alpha) and 2alpha (HIF-2alpha) are key regulators of the transcriptional response to low oxygen and are closely related in domain architecture, DNA binding, and activation mechanisms. Despite these similarities, targeted disruption of the HIF-alpha genes in mice results in distinctly different phenotypes demonstrating nonredundancy of function, although the underlying mechanisms remain unclear. Here we report on the novel and specific interaction of HIF-2alpha, but not HIF-1alpha, with the NF-kappaB essential modulator (NEMO) using immunoprecipitation, mammalian two-hybrid, and in vitro protein interaction assays. Reporter gene assays demonstrate that this interaction specifically enhances normoxic HIF-2alpha transcriptional activity, independently of the HIF-2alpha transactivation domain, consistent with a model by which NEMO aids CBP/p300 recruitment to HIF-2alpha. In contrast, HIF-2alpha overexpression does not alter NF-kappaB signaling, suggesting that the functional consequence of the HIF-2alpha/NEMO interaction is limited to the HIF pathway. The specificity of NEMO for HIF-2alpha represents one of the few known differential protein-protein interactions between the HIF-alpha proteins, which has important implications for the activity of HIF-2alpha and is also the first postulated NF-kappaB-independent role for NEMO.
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Affiliation(s)
- Cameron P Bracken
- School of Molecular and Biomedical Science and the Centre for the Molecular Genetics of Development, University of Adelaide, Adelaide, South Australia, 5005, Australia
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303
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Kaelin WG. The von Hippel-Lindau tumor suppressor protein: roles in cancer and oxygen sensing. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2005; 70:159-66. [PMID: 16869749 DOI: 10.1101/sqb.2005.70.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Biallelic inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is a common event in hereditary (von Hippel- Lindau disease) and sporadic hemangioblastomas and clear-cell renal carcinomas. Germ-line VHL mutations are also linked to some hereditary pheochromocytoma families. The VHL gene product, pVHL, interacts with a number of cellular proteins and is implicated in the control of angiogenesis, extracellular matrix formation, cell metabolism, and mitogenesis. The best understood function of pVHL relates to its role as the substrate recognition unit of an E3 ligase that targets the heterodimeric transcription factor HIF (hypoxia-inducible factor) for destruction in the presence of oxygen. Down-regulation of HIF appears to be both necessary and sufficient for renal tumor suppression by pVHL, and HIF is strongly suspected of contributing to hemangioblastoma development as well. Recent work suggests that pVHL's role in pheochromocytoma is not related to HIF but rather to the ability of pVHL to regulate neuronal apoptosis, which is mediated by c-Jun, when growth factors such as NGF become limiting. Loss of pVHL leads to up-regulation of JunB, which antagonizes c-Jun and blunts apoptosis.
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Affiliation(s)
- W G Kaelin
- Howard Hughes Medical Institute, Dana-Farber and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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304
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Abstract
Hypoxia plays a major role in the induction of angiogenesis during tumor development. One mechanism by which tumor cells respond to a reduced oxygen level is via the activation of hypoxia-inducible factor-1 (HIF-1). HIF-1 is an oxygen-dependent transcriptional activator that plays crucial roles in the angiogenesis of tumors and mammalian development. HIF-1 consists of a constitutively expressed HIF-1beta subunit and the highly regulated HIF-1alpha subunits. The stability and activity of HIF-1alpha are regulated by various post-translational modifications, hydroxylation, acetylation, phosphorylation and sumoyaltion. Therefore, HIF-1alpha interacts with several protein factors including PHD, pVHL, ARD-1, SUMO and p300/CBP. Under normoxia, the HIF-1alpha subunit is rapidly degraded via the von Hippel-Lindau tumor suppressor gene product (pVHL)-mediated ubiquitin/proteasome pathway. The association of pVHL and HIF-1alpha under normoxic conditions is triggered by the hydroxylation of prolines and the acetylation of lysine within a polypeptide segment known as the oxygen-dependent degradation (ODD) domain. On the contrary, under the hypoxia condition, the HIF-1alpha subunit becomes stable and interacts with coactivators such as p300/CBP to modulate its transcriptional activity. Under hypoxic conditions, HIF-1 eventually acts as a master regulator of numerous hypoxia-inducible genes. The target genes of HIF-1 are especially related to angiogenesis, cell proliferation and survival, and to glucose and iron metabolism. Moreover, it was reported that the activation of HIF-1alpha is closely associated with a variety of tumors and oncogenic pathways. Hence, the blocking of HIF-1alpha itself or the blocking of HIF-1alpha interacting proteins inhibits tumor growth. Based on these findings, HIF-1 can be a prime target for anticancer therapies. Therefore, this review summarizes the molecular mechanism of HIF-1alpha stability, the biological functions of HIF-1 and its potential applications for cancer therapies.
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Affiliation(s)
- Soon-Sun Hong
- Research Institute of Pharmaceutical Sciences and College of Pharmacy, Seoul National University, Seoul, Korea
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305
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Abstract
The von Hippel-Lindau tumor suppressor gene (VHL), which resides on chromosome 3p25, is mutated or silenced in >50% of sporadic clear cell renal cell carcinomas. Germ-line VHL mutations give rise to VHL disease, which is characterized by an increased risk of blood vessel tumors (hemangioblastomas) and renal cell carcinomas. In this setting, VHL inactivation gives rise to premalignant renal cysts. Additional genetic alterations are presumably required for conversion of these cysts to renal cell carcinomas. Restoration of VHL function in VHL-/- renal cell carcinomas is sufficient to inhibit tumorigenesis in vivo. On the basis of these and other data, VHL appears to be a critical gatekeeper with respect to the development of renal cell carcinoma. The VHL gene product, pVHL, is the substrate recognition module of an E3 ubiquitin ligase that targets the hypoxia-inducible factor (HIF) for destruction in the presence of oxygen. Hypoxic cells, or cells lacking pVHL, accumulate high levels of HIF, which activates the transcription of a variety of genes, including vascular endothelial growth factor, platelet-derived growth factor B, and transforming growth factor alpha. We have demonstrated that inhibition of HIF is necessary and sufficient for tumor suppression by pVHL in renal cell carcinoma nude mouse xenograft assays. This provides a rationale for treating VHL-/- renal cell carcinoma with inhibitors of HIF or its downstream targets. Genotype-phenotype correlations in VHL disease suggest, however, that pVHL has targets in addition to HIF. Elucidating these targets should provide a more complete picture of how pVHL suppresses tumor growth.
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Affiliation(s)
- William G Kaelin
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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306
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Linehan WM, Vasselli J, Srinivasan R, Walther MM, Merino M, Choyke P, Vocke C, Schmidt L, Isaacs JS, Glenn G, Toro J, Zbar B, Bottaro D, Neckers L. Genetic basis of cancer of the kidney: disease-specific approaches to therapy. Clin Cancer Res 2004; 10:6282S-9S. [PMID: 15448018 DOI: 10.1158/1078-0432.ccr-050013] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studies during the past two decades have shown that kidney cancer is not a single disease; it is made up of a number of different types of cancer that occur in this organ. Clear cell renal carcinoma is characterized by mutation of the VHL gene. The VHL gene product forms a heterotrimeric complex with elongin C, elongin B, and Cul-2 to target hypoxia-inducible factors 1 and 2alpha for ubiquitin-mediated degradation. VHL-/- clear cell renal carcinoma overexpresses epidermal growth factor receptor and transforming growth factor alpha. Both hypoxia-inducible factor 1alpha and the epidermal growth factor receptor are potential therapeutic targets in clear cell renal carcinoma. Studies of the hereditary form of renal cell carcinoma (RCC) associated with hereditary papillary renal carcinoma (HPRC) determined that the c-Met proto-oncogene on chromosome 7 is the gene for HPRC and for a number of sporadic papillary RCCs. The HPRC c-Met mutations are activating mutations in the tyrosine kinase domain of the gene. The gene for a new form of hereditary RCC (Birt Hogg Dubé syndrome) associated with cutaneous tumors, lung cysts, and colon polyps or cancer has recently been identified. Studies are currently under way to determine what type of gene BHD is and how damage to this gene leads to kidney cancer. Individuals affected with hereditary leiomyomatosis renal cell carcinoma are at risk for the development of cutaneous leiomyomas, uterine leiomyomas (fibroids), and type 2 papillary RCC. The HLRC gene has been found to be the Krebs cycle enzyme, fumarate hydratase. Studies are under way to understand the downstream pathway of this cancer gene.
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Affiliation(s)
- W Marston Linehan
- Urologic Oncology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland 20892-1501, USA.
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307
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Bishop T, Lau KW, Epstein ACR, Kim SK, Jiang M, O'Rourke D, Pugh CW, Gleadle JM, Taylor MS, Hodgkin J, Ratcliffe PJ. Genetic analysis of pathways regulated by the von Hippel-Lindau tumor suppressor in Caenorhabditis elegans. PLoS Biol 2004; 2:e289. [PMID: 15361934 PMCID: PMC515368 DOI: 10.1371/journal.pbio.0020289] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Accepted: 06/29/2004] [Indexed: 11/19/2022] Open
Abstract
The von Hippel-Lindau (VHL) tumor suppressor functions as a ubiquitin ligase that mediates proteolytic inactivation of hydroxylated α subunits of hypoxia-inducible factor (HIF). Although studies of VHL-defective renal carcinoma cells suggest the existence of other VHL tumor suppressor pathways, dysregulation of the HIF transcriptional cascade has extensive effects that make it difficult to distinguish whether, and to what extent, observed abnormalities in these cells represent effects on pathways that are distinct from HIF. Here, we report on a genetic analysis of HIF-dependent and -independent effects of VHL inactivation by studying gene expression patterns in Caenorhabditis elegans. We show tight conservation of the HIF-1/VHL-1/EGL-9 hydroxylase pathway. However, persisting differential gene expression in hif-1 versus hif-1; vhl-1 double mutant worms clearly distinguished HIF-1–independent effects of VHL-1 inactivation. Genomic clustering, predicted functional similarities, and a common pattern of dysregulation in both vhl-1 worms and a set of mutants (dpy-18, let-268, gon-1, mig-17, and unc-6), with different defects in extracellular matrix formation, suggest that dysregulation of these genes reflects a discrete HIF-1–independent function of VHL-1 that is connected with extracellular matrix function. Besides its known function of inactivating hypoxia-inducible factor (HIF), genetically engineered worms clearly demonstrate that there exist HIF-independent effects of the von Hippel- Lindau tumor suppressor
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Affiliation(s)
- Tammie Bishop
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Kah Weng Lau
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Andrew C. R Epstein
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Stuart K Kim
- 2Department of Developmental Biology and Genetics, Stanford University Medical CenterStanford, CaliforniaUnited States of America
| | - Min Jiang
- 2Department of Developmental Biology and Genetics, Stanford University Medical CenterStanford, CaliforniaUnited States of America
| | - Delia O'Rourke
- 3Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Christopher W Pugh
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Jonathan M Gleadle
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Martin S Taylor
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
| | - Jonathan Hodgkin
- 3Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Peter J Ratcliffe
- 1The Henry Wellcome Building of Genomic Medicine, University of OxfordOxfordUnited Kingdom
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308
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Affiliation(s)
- W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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309
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Abstract
PURPOSE OF REVIEW Although pathological findings including tumour grade and tumour-node-metastasis stage provide prognostic information, the outcome for patients with renal cell carcinoma is occasionally unpredictable. Many studies have been undertaken to improve prediction of the prognosis of renal cell carcinoma, along with efforts to clarify the pathogenesis of renal cell carcinoma at the molecular level. This article reviews the advances in renal cell carcinoma research relevant to pathology published between 1 May 2002 and 30 April 2003. RECENT FINDINGS The establishment of a strict tumour grading system or adding microscopic venous invasion or tumour necrosis is potentially useful for predicting patient outcomes. The contribution of the von Hippel-Lindau-related pathway in early carcinogenesis has been partly revealed with regard to angiogenesis and cell cycle control. Tumour development in renal cell carcinoma can be considered as accumulating heterogenous molecular events related to cytokine production, cell cycle control, anti-apoptotic signal machinery and angiogenesis. SUMMARY Finding the target genes related to the von Hippel-Lindau pathway may explain the resistance of chemotherapy, and also provide a clue to finding a novel therapeutic option. Molecular targeting therapy can be applicable after more general molecules leading to tumour development and the metastasis of renal cell carcinoma have been identified.
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Affiliation(s)
- Mototsugu Oya
- Department of Urology, Keio University School of Medicine, Tokyo, Japan.
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310
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Abstract
Ubiquitin (Ub)-protein conjugation represents a novel means of posttranscriptional modification in a proteolysis-dependent or -independent manner. E3 Ub ligases play a key role in governing the cascade of Ub transfer reactions by recognizing and catalyzing Ub conjugation to specific protein substrates. The E3s, which can be generally classified into HECT-type and RING-type families, are involved in the regulation of many aspects of the immune system, including the development, activation, and differentiation of lymphocytes, T cell-tolerance induction, antigen presentation, immune evasion, and virus budding. E3-promoted ubiquitination affects a wide array of biological processes, such as receptor downmodulation, signal transduction, protein processing or translocation, protein-protein interaction, and gene transcription, in addition to proteasome-mediated degradation. Deficiency or mutation of some of the E3s like Cbl, Cbl-b, or Itch, causes abnormal immune responses such as autoimmunity, malignancy, and inflammation. This review discusses our current understanding of E3 Ub ligases in both innate and adaptive immunity. Such knowledge may facilitate the development of novel therapeutic approaches for immunological diseases.
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Affiliation(s)
- Yun-Cai Liu
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA.
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311
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Sufan RI, Jewett MAS, Ohh M. The role of von Hippel-Lindau tumor suppressor protein and hypoxia in renal clear cell carcinoma. Am J Physiol Renal Physiol 2004; 287:F1-6. [PMID: 15180922 DOI: 10.1152/ajprenal.00424.2003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The majority of kidney cancers are caused by the mutation of the von Hippel-Lindau (VHL) tumor suppressor gene. VHL protein (pVHL) is part of an E3 ubiquitin ligase complex called VEC that is composed of elongin B, elongin C, cullin 2, NEDD8, and Rbx1. VEC targets a hypoxia-inducible factor (HIF) transcription factor for ubiquitin-mediated destruction selectively in the presence of oxygen. In the absence of wild-type pVHL, as in VHL patients or in the majority of sporadic clear cell renal cell carcinomas, HIF-responsive genes are inappropriately activated even under normoxia. Recent insights into the molecular mechanisms regulating the function of pVHL, and thereby HIF, in the context of kidney cancer are the focus of this review.
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Affiliation(s)
- Roxana I Sufan
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
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312
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Abstract
The LKB1 tumor suppressor protein controls the activity of the TSC1/TSC2 tumor suppressor complex. Mutations in LKB1 cause Peutz-Jeghers syndrome (PJS), and mutations in either TSC1 or TSC2 cause tuberous sclerosis complex--two syndromes characterized by the development of hamartomas. LKB1 activation by energy deprivation activates AMPK, which in turn phosphorylates and activates TSC2. TSC2 activation results in the inactivation of mTOR, a critical regulator of protein translation. How mTOR dysregulation after inactivation of LKB1 or TSC1/2 contributes to hamartoma development is not known. However, hypoxia-inducible factor (HIF) and VEGF are regulated by mTOR and are likely to play a contributory role.
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Affiliation(s)
- James Brugarolas
- Dana-Farber Cancer Institute and Harvard Medical School, Howard Hughes Medical Institute, 44 Binney Street, Mayer 457, Boston, Massachusetts 02115, USA
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313
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Palayoor ST, Burgos MA, Shoaibi A, Tofilon PJ, Coleman CN. Effect of Radiation and Ibuprofen on Normoxic Renal Carcinoma Cells Overexpressing Hypoxia-Inducible Factors by Loss of von Hippel–Lindau Tumor Suppressor Gene Function. Clin Cancer Res 2004; 10:4158-64. [PMID: 15217953 DOI: 10.1158/1078-0432.ccr-04-0005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Tumor hypoxia is a major limiting factor for radiation therapy. Hypoxia-inducible factors (HIFs) are overexpressed in several human cancers and are considered prognostic markers and potential targets for cancer therapy. The purpose of the present study was to investigate the impact of HIFs on radiosensitivity. EXPERIMENTAL DESIGN Renal clear cell carcinoma (RCC) cell lines overexpressing HIFs under normoxic conditions because of inactivation of von Hippel-Lindau tumor suppressor gene function (VHL-ve) and their matched pairs in which overexpression of HIFs was abolished by expression of functional VHL (VHL+ve) were irradiated. Radiosensitivity was determined by clonogenic assay. HIF and VHL protein levels were evaluated by Western blot analysis. RCC cells were also treated with ibuprofen, a radiosensitizer and HIF inhibitor in prostate cancer cells. The effect of ibuprofen on radiosensitization and HIF and VHL proteins was compared in RCC matched-pair cell lines. RESULTS The data showed only small differences in the radiosensitivity between the cells overexpressing HIFs and cells with basal HIF levels. The dose-modifying factors for C2, 786-0, and A498 RCC cells were 1.14, 1.14 and 1.15, respectively. Radiation did not alter HIF or VHL protein levels. Ibuprofen inhibited HIFs in VHL+ve cells expressing basal levels of HIFs. In VHL-ve cells overexpressing HIFs, the inhibition was very modest. Ibuprofen radiosensitized C2 RCC cells to the same extent irrespective of their HIF status. CONCLUSIONS Overexpression of HIFs in RCC cells harboring VHL mutations has only a modest effect on the radiosensitivity. Radiosensitization by ibuprofen appears to be independent of HIF status.
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Affiliation(s)
- Sanjeewani T Palayoor
- Radiation Oncology Branch, Center for Cancer Research and the Molecular Radiation Therapeutics Branch, Division of Cancer and Treatment and Diagnosis, National Cancer Institute, NIH, Bethesda, Maryland, USA.
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314
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Abstract
Hypoxia, or lowered physiological oxygenation, is a component of many diseases. The response to decreased oxygen tensions is also an essential aspect of normal development and physiology. The hypoxic response is chiefly mediated by a single transcription factor--the hypoxia-inducible transcription factor HIF-1. The central role played by HIF-1 in hypoxia-induced transcription has made the focus of intense investigation by biologists from a wide range of disciplines. Recent developments have produced fundamental advances in our understanding of both the regulation and function of this response pathway in animals, and illustrated the potential for manipulation of the pathway for therapeutic purposes.
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Affiliation(s)
- Lorenz Poellinger
- Cell and Molecular Biology, the Karolinska Institute, Stockholm, Sweden
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315
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Affiliation(s)
- Christian P Pavlovich
- Johns Hopkins Bayview Medical Center, Brady Urological Institute, A-345, 4940 Eastern Ave., Baltimore, Maryland 21224, USA.
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316
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Jensen RL, Gillespie D, House P, Layfield L, Shelton C. Endolymphatic sac tumors in patients with and without von Hippel-Lindau disease: the role of genetic mutation, von Hippel-Lindau protein, and hypoxia inducible factor-1alpha expression. J Neurosurg 2004; 100:488-97. [PMID: 15035285 DOI: 10.3171/jns.2004.100.3.0488] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECT Endolymphatic sac (ELS) tumors are low-grade malignancies of the temporal bone that are associated with von Hippel-Lindau (VHL) disease but can also occur sporadically. The VHL gene product VHL protein is important in the regulation of hypoxia inducible factor (HIF)-1alpha, which controls expression of molecules that are important in angiogenesis and cell metabolism. In this study the authors examine the role of VHL and HIF-1 in ELS tumors. METHODS The ELS tumors from three patients were examined using the following method: DNA from tumor tissue was isolated, amplified by polymerase chain reaction and the VHL gene sequence was compared with the known wild-type sequence. Loss of heterozygosity (LOH) studies were performed to confirm the sequencing data. Immunohistochemical evaluation for VHL, HIF-1alpha, vascular endothelial growth factor (VEGF), and carbonic anhydrase IX (CA IX) was performed. Snap-frozen tumor tissue was examined using Western blot and HIF-1 immunoassays for HIF-1alpha and VHL expression. Two patients had sporadic ELS tumors and the other one suffered from VHL disease. Results of VHL gene sequencing were normal in the tissue derived from the sporadic ELS tumors. The ELS tumor, pheochromocytoma, and spinal hemangioblastoma were heterozygous for the same C-to-A transversion found in the germline carried by the patient with VHL disease. No LOH was detected in the tumor tissue obtained in the patient with VHL disease. Expression of HIF-1alpha, VEGF, and CA IX evaluated using immunohistochemical studies was elevated in the VHL-associated tumors. Nevertheless, Western blots and immunoassays for HIF-1alpha did not show elevated expression in these tumors. CONCLUSIONS The sporadic and VHL disease-associated ELS tumors in this study had normal VHL-mediated HIF-1 regulation. This is a result of normal VHL gene expression in the case of the sporadic ELS tumor. In the VHL-associated ELS tumor, this is due to one normal copy of the VHL gene and adequate VHL gene expression.
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Affiliation(s)
- Randy L Jensen
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah 84132-2303, USA.
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317
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Höpfl G, Ogunshola O, Gassmann M. HIFs and tumors--causes and consequences. Am J Physiol Regul Integr Comp Physiol 2004; 286:R608-23. [PMID: 15003941 DOI: 10.1152/ajpregu.00538.2003] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
For most organisms oxygen is essential fo life. When oxygen levels drop below those required to maintain the minimum physiological oxygen requirement of an organism or tissue it is termed hypoxia. To counter act possible deleterious effects of such a state, an immediate molecular response is initiated causing adaptation responses aimed at cell survival. This response is mediated by the hypoxia-inducible factor-1 (HIF-1), which is a heterodimer consisting of an alpha- and a beta-subunit. HIF-1 alpha protein is stabilized under hypoxic conditions and therefore confers selectivity to this response. Hypoxia is characteristic of tumors, mainly because of impaired blood supply resulting from abnormal growth. Over the past few years enormous progress has been made in the attempt to understand how the activation of the physiological response to hypoxia influences neoplastic growth. In this review some aspects of HIF-1 pathway activation in tumors and the consequences for pathophysiology and treatment of neoplasia are discussed.
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Affiliation(s)
- Gisele Höpfl
- Institute of Veterinary Physiology, University of Zürich, Winterthurerstrasse 260, CH-8057 Zürich, Switzerland
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318
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Abstract
Accumulating evidence points to a key role of the ubiquitin-proteasome pathway in oncogenesis. Aberrant proteolysis of substrates involved in cellular processes such as the cell division cycle, gene transcription, the DNA damage response and apoptosis has been reported to contribute significantly to neoplastic transformation. Cullin-dependent ubiquitin ligases (CDLs) form a class of structurally related multisubunit enzymes central to the ubiquitin-mediated proteolysis of many important biological substrates. In this review, we describe the role of CDLs in the ubiquitinylation of cancer-related substrates and discuss how altered ubiquitinylation by CDLs may contribute to tumor development.
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Affiliation(s)
- Daniele Guardavaccaro
- Department of Pathology and NYU Cancer Institute, MSB 599, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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319
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Zimmer M, Doucette D, Siddiqui N, Iliopoulos O. Inhibition of Hypoxia-Inducible Factor Is Sufficient for Growth Suppression of VHL−/− Tumors. Mol Cancer Res 2004. [DOI: 10.1158/1541-7786.89.2.2] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The von Hippel-Lindau tumor suppressor protein (pVHL) is a substrate receptor for the mammalian SCF-2 E3 ubiquitin ligase complex that targets several substrates for ubiquitination and proteasomal degradation. Among these targets are the α-regulatory subunits of the hypoxia-inducible factor (HIF). VHL−/− cells constitutively overexpress hypoxia-inducible genes through both transcriptional and posttranscriptional mechanisms and form tumors when injected into nude mice. Reintroduction of pVHL into VHL−/− cell lines restores normal oxygen-dependent regulation of these genes and suppresses tumor formation in the mouse xenograft assay. We report here that short hairpin RNA-mediated inactivation of HIF phenocopies the effects of pVHL reintroduction with respect to decreased expression of hypoxia-inducible genes, decreased ability to promote vascular endothelial cell proliferation in vitro, and tumor growth suppression in vivo. In addition, HIF inactivation abrogated the cellular response to hypoxia, indicating that HIF is the only pVHL target required for this response. These data suggest that deregulation of hypoxia-inducible genes in VHL−/− cells can be attributed mainly to deregulation of HIF and validate HIF as a therapeutic anticancer drug target.
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Affiliation(s)
- Michael Zimmer
- Hematology-Oncology Unit, Department of Medicine, Massachusetts General Hospital and the Massachusetts General Hospital Cancer Center, Boston, MA
| | - Darrell Doucette
- Hematology-Oncology Unit, Department of Medicine, Massachusetts General Hospital and the Massachusetts General Hospital Cancer Center, Boston, MA
| | - Naila Siddiqui
- Hematology-Oncology Unit, Department of Medicine, Massachusetts General Hospital and the Massachusetts General Hospital Cancer Center, Boston, MA
| | - Othon Iliopoulos
- Hematology-Oncology Unit, Department of Medicine, Massachusetts General Hospital and the Massachusetts General Hospital Cancer Center, Boston, MA
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320
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Zhou MI, Wang H, Foy RL, Ross JJ, Cohen HT. Tumor Suppressor von Hippel-Lindau (VHL) Stabilization of Jade-1 Protein Occurs through Plant Homeodomains and Is VHL Mutation Dependent. Cancer Res 2004; 64:1278-86. [PMID: 14973063 DOI: 10.1158/0008-5472.can-03-0884] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The von Hippel-Lindau (VHL) gene is the major renal cancer gene in adults. The mechanism of renal tumor suppression by VHL protein is only partly elucidated. VHL loss increases expression of the hypoxia-inducible factor alpha transcription factors. However, clinical and biochemical data indicate that the hypoxia-inducible factors are necessary but not sufficient for renal tumorigenesis, which suggests other VHL effector pathways are involved. Jade-1 protein interacts strongly with VHL and is most highly expressed in renal proximal tubules, precursor cells of renal cancer. Short-lived Jade-1 protein contains plant homeodomain (PHD) and candidate PEST degradation motifs and is substantially stabilized by VHL. The effect of VHL on Jade-1 protein abundance and relative protein stability was further examined in immunoblots and metabolic labeling experiments using two time points. VHL-Jade-1 binding was tested in coimmunoprecipitations. In cotransfection studies with wild-type VHL, the Jade-1 PHD-extended PHD module, not the candidate PEST domain, was required for full VHL-mediated stabilization. This module is also found in leukemia transcription factors AF10 and AF17, as well as closely related Jade-like proteins, which suggests all might be VHL regulated. Intriguingly, naturally occurring truncations and mutations of VHL affected wild-type Jade-1 binding and stabilization. Although the VHL beta domain was sufficient for Jade-1 binding, both the alpha and beta domains were required for Jade-1 stabilization. Thus, truncating VHL mutations, which are severe and associated with renal cancer development, prevented Jade-1 stabilization. Moreover, well-controlled cotransfection and metabolic labeling experiments revealed that VHL missense mutations that cause VHL disease without renal cancer, such as Tyr98His and Tyr112His, stabilized Jade-1 fully. In contrast, like the VHL truncations, VHL missense mutations commonly associated with renal cancer, such as Leu118Pro or Arg167Trp, did not stabilize Jade-1 fully. Therefore, loss of Jade-1 stability may correlate with renal cancer risk. Endogenous Jade-1 in stable renal cancer lines also exhibited VHL mutation-dependent regulation. As in the cotransfections, VHL truncations did not increase endogenous Jade-1 abundance, whereas the VHL missense mutations tested partially increased Jade-1 expression. Additional studies with non-PHD proteins indicated that Jade-1 stabilization by VHL is highly specific. Fibronectin was not stabilized like Jade-1 by VHL, nor were candidate VHL interactors from a yeast screen. Thus, protein stabilization likely reflects the biological activity of largely intact VHL protein on the PHD-extended PHD module of Jade-1. Dysregulation of the VHL protein stabilization pathway or of Jade-1 itself may therefore contribute to VHL renal disease and renal cancer pathogenesis.
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Affiliation(s)
- Mina I Zhou
- Renal and Hematology/Oncology Sections, Departments of Medicine and Pathology, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA
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321
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Maynard MA, Ohh M. Von Hippel-Lindau tumor suppressor protein and hypoxia-inducible factor in kidney cancer. Am J Nephrol 2004; 24:1-13. [PMID: 14654728 DOI: 10.1159/000075346] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Accepted: 10/20/2003] [Indexed: 12/31/2022]
Abstract
The development of hereditary von Hippel-Lindau (VHL) disease and the majority of sporadic kidney cancers are due to the functional inactivation of the VHL gene. The product of the VHL gene, pVHL, in association with elongins B and C, cullin 2, and Rbx1 form an E3 ubiquitin-ligase complex VEC that targets the alpha subunits of hypoxia-inducible factor (HIF) for ubiquitination. Ubiquitin-tagged HIF-alpha proteins are subsequently degraded by the common 26S proteasome. pVHL functions as the substrate-docking interface that specifically recognizes prolyl-hydroxylated HIF-alpha. This hydroxylation occurs only in the presence of oxygen or normoxia. Thus, under hypoxia, HIF-alpha subunits are no longer subjected to degradation and are thereby able to dimerize with the common and constitutively stable beta subunits. The heterodimeric HIFs upregulate a myriad of hypoxia-inducible genes, triggering our physiologic response to hypoxia. Inappropriate accumulations of HIF-alpha in VHL disease are believed to contribute to the pathogenesis via the upregulation of several of these HIF target genes. Our current molecular understanding of the roles of HIF and pVHL in the development of VHL-associated clear-cell renal cell carcinoma (CC-RCC) is the focus of this review.
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Affiliation(s)
- Mindy A Maynard
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ont., Canada
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322
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Willam C, Nicholls LG, Ratcliffe PJ, Pugh CW, Maxwell PH. The prolyl hydroxylase enzymes that act as oxygen sensors regulating destruction of hypoxia-inducible factor α. ACTA ACUST UNITED AC 2004; 44:75-92. [PMID: 15581484 DOI: 10.1016/j.advenzreg.2003.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Carsten Willam
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
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323
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Abstract
Cellular oxygen (O2) concentrations are tightly regulated to maintain ATP levels required for metabolic reactions in the human body. Responses to changes in O2 concentrations are primarily regulated by the transcription factor hypoxia inducible factor (HIF). HIF activates transcription of genes that increase systemic O2 delivery or provide cellular metabolic adaptation under conditions of hypoxia. HIF activity is essential for embryogenesis and various processes in postnatal life, and therefore, HIF levels need to be precisely controlled. Abnormal HIF expression is related to numerous diseases of the vascular system, including heart disease, cancer, and chronic obstructive pulmonary disease.
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Affiliation(s)
- Kelly L Covello
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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324
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Aprelikova O, Chandramouli GVR, Wood M, Vasselli JR, Riss J, Maranchie JK, Linehan WM, Barrett JC. Regulation of HIF prolyl hydroxylases by hypoxia-inducible factors. J Cell Biochem 2004; 92:491-501. [PMID: 15156561 DOI: 10.1002/jcb.20067] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hypoxia and induction of hypoxia-inducible factors (HIF-1alpha and HIF-2alpha) is a hallmark of many tumors. Under normal oxygen tension HIF-alpha subunits are rapidly degraded through prolyl hydroxylase dependent interaction with the von Hippel-Lindau (VHL) tumor suppressor protein, a component of E3 ubuiquitin ligase complex. Using microarray analysis of VHL mutated and re-introduced cells, we found that one of the prolyl hydroxylases (PHD3) is coordinately expressed with known HIF target genes, while the other two family members (PHD1 and 2) did not respond to VHL. We further tested the regulation of these genes by HIF-1 and HIF-2 and found that siRNA targeted degradation of HIF-1alpha and HIF-2alpha results in decreased hypoxia-induced PHD3 expression. Ectopic overexpression of HIF-2alpha in two different cell lines provided a much better induction of PHD3 gene than HIF-1alpha. In contrast, we demonstrate that PHD2 is not affected by overexpression or downregulation of HIF-2alpha. However, induction of PHD2 by hypoxia has HIF-1-independent and -dependent components. Short-term hypoxia (4 h) results in induction of PHD2 independent of HIF-1, while PHD2 accumulation by prolonged hypoxia (16 h) was decreased by siRNA-mediated degradation of HIF-1alpha subunit. These data further advance our understanding of the differential role of HIF factors and putative feedback loop in HIF regulation.
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Affiliation(s)
- Olga Aprelikova
- Laboratory of Biosystems and Cancer, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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325
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Hu CJ, Wang LY, Chodosh LA, Keith B, Simon MC. Differential roles of hypoxia-inducible factor 1alpha (HIF-1alpha) and HIF-2alpha in hypoxic gene regulation. Mol Cell Biol 2003; 23:9361-74. [PMID: 14645546 PMCID: PMC309606 DOI: 10.1128/mcb.23.24.9361-9374.2003] [Citation(s) in RCA: 1046] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Revised: 04/24/2003] [Accepted: 09/04/2003] [Indexed: 12/13/2022] Open
Abstract
Transcriptional responses to hypoxia are primarily mediated by hypoxia-inducible factor (HIF), a heterodimer of HIF-alpha and the aryl hydrocarbon receptor nuclear translocator subunits. The HIF-1alpha and HIF-2alpha subunits are structurally similar in their DNA binding and dimerization domains but differ in their transactivation domains, implying they may have unique target genes. Previous studies using Hif-1alpha(-/-) embryonic stem and mouse embryonic fibroblast cells show that loss of HIF-1alpha eliminates all oxygen-regulated transcriptional responses analyzed, suggesting that HIF-2alpha is dispensable for hypoxic gene regulation. In contrast, HIF-2alpha has been shown to regulate some hypoxia-inducible genes in transient transfection assays and during embryonic development in the lung and other tissues. To address this discrepancy, and to identify specific HIF-2alpha target genes, we used DNA microarray analysis to evaluate hypoxic gene induction in cells expressing HIF-2alpha but not HIF-1alpha. In addition, we engineered HEK293 cells to express stabilized forms of HIF-1alpha or HIF-2alpha via a tetracycline-regulated promoter. In this first comparative study of HIF-1alpha and HIF-2alpha target genes, we demonstrate that HIF-2alpha does regulate a variety of broadly expressed hypoxia-inducible genes, suggesting that its function is not restricted, as initially thought, to endothelial cell-specific gene expression. Importantly, HIF-1alpha (and not HIF-2alpha) stimulates glycolytic gene expression in both types of cells, clearly showing for the first time that HIF-1alpha and HIF-2alpha have unique targets.
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Affiliation(s)
- Cheng-Jun Hu
- Abramson Family Cancer Research Institute. Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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326
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Abstract
Significant advances have been made in the understanding of the genetic basis of familial renal neoplasia. Identification of key genes in the pathogenesis of various hereditary renal cancer syndromes has provided opportunities to screen family members at risk and to explore the significance of these genetic abnormalities in the development and genesis of much more common sporadic counterparts. As researchers continue to delineate critical carcinogenic pathways and accumulate expansive knowledge on oncogenic mechanisms driving cancer initiation and progression at the cellular and molecular levels, this information will be integrated and translated into effective diagnostic and therapeutic strategies that will dictate clinical management of all renal cancers.
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Affiliation(s)
- Jonathan J Hwang
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bldg#10, Room 2B47, Bethesda, MD 20892, USA
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327
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Abstract
ABSTRACT. Recent studies of a relatively rare hereditary cancer syndrome, von Hippel-Lindau (VHL) disease, have shed new light on the molecular pathogenesis of kidney cancer and, perhaps more important, on how mammalian cells sense and respond to changes in oxygen availability. This knowledge is already translating into new therapeutic targets for kidney cancer as well as for multiple conditions, such as myocardial infarction and stroke, in which ischemia plays a pathogenic role. This review summarizes the current knowledge of the molecular pathogenesis of von Hippel-Lindau disease and the role of the VHL gene product (pVHL) in kidney cancer and the mammalian oxygen sensing pathway. E-mail: william_kaelin@dfci.harvard.edu
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Affiliation(s)
- William G Kaelin
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute, and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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328
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Abstract
Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes that are involved in crucial aspects of cancer biology, including angiogenesis, cell survival, glucose metabolism and invasion. Intratumoral hypoxia and genetic alterations can lead to HIF-1alpha overexpression, which has been associated with increased patient mortality in several cancer types. In preclinical studies, inhibition of HIF-1 activity has marked effects on tumour growth. Efforts are underway to identify inhibitors of HIF-1 and to test their efficacy as anticancer therapeutics.
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Affiliation(s)
- Gregg L Semenza
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3914, USA.
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329
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Percy MJ, Mooney SM, McMullin MF, Flores A, Lappin TRJ, Lee FS. A common polymorphism in the oxygen-dependent degradation (ODD) domain of hypoxia inducible factor-1alpha (HIF-1alpha) does not impair Pro-564 hydroxylation. Mol Cancer 2003; 2:31. [PMID: 14521712 PMCID: PMC212228 DOI: 10.1186/1476-4598-2-31] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Accepted: 09/09/2003] [Indexed: 01/12/2023] Open
Abstract
Background The hypoxia-inducible factor (HIF) transcription complex, which is activated by low oxygen tension, controls a diverse range of cellular processes including angiogenesis and erythropoiesis. Under normoxic conditions, the α subunit of HIF is rapidly degraded in a manner dependent on hydroxylation of two conserved proline residues at positions 402 and 564 in HIF-1α in the oxygen-dependent degradation (ODD) domain. This allows subsequent recognition by the von Hippel-Lindau (VHL) tumor suppressor protein, which targets HIF for degradation by the ubiquitin-proteasome pathway. Under hypoxic conditions, prolyl hydroxylation of HIF is inhibited, allowing it to escape VHL-mediated degradation. The transcriptional regulation of the erythropoietin gene by HIF raises the possibility that HIF may play a role in disorders of erythropoiesis, such as idiopathic erythrocytosis (IE). Results Patients with IE were screened for changes in the HIF-1α coding sequence, and a change in the ODD domain that converts Pro-582 to Ser was identified in several patients. This same change, however, was also detected at a significant frequency, 0.073, in unaffected controls compared to 0.109 in the IE patient group. In vitro hydroxylation assays examining this amino acid change failed to reveal a discernible effect on HIF hydroxylation at Pro-564. Conclusion The Pro582Ser change represents a common polymorphism of HIF-1α that does not impair HIF-1α prolyl hydroxylation. Although the Pro582Ser polymorphism is located in the ODD domain of HIF-1α it does not diminish the association of HIF-1α with VHL. Thus, it is unlikely that this polymorphism accounts for the erythrocytosis in the group of IE patients studied.
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Affiliation(s)
- Melanie J Percy
- Department of Haematology, Belfast City Hospital, Belfast, Northern Ireland, BT9 7AB, UK
| | - Sharon M Mooney
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Mary Frances McMullin
- Department of Haematology, Queen's University, Belfast, Northern Ireland, BT9 7AB, UK
| | - Adrian Flores
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Terence RJ Lappin
- Department of Haematology, Queen's University, Belfast, Northern Ireland, BT9 7AB, UK
| | - Frank S Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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330
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Tang TTL, Lasky LA. The forkhead transcription factor FOXO4 induces the down-regulation of hypoxia-inducible factor 1 alpha by a von Hippel-Lindau protein-independent mechanism. J Biol Chem 2003; 278:30125-35. [PMID: 12761217 DOI: 10.1074/jbc.m302042200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Tumors utilize hyperactivation of the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway to cope with deleterious environmental conditions. Activation of the PI3K/AKT pathway has been shown to increase protein expression of the alpha subunit of the hypoxia-inducible factor (HIF) 1, a key regulator of oxygen homeostasis. Elevated levels of HIF-1 alpha induce expression of genes with critical roles in angiogenesis, erythropoiesis, and glucose metabolism, processes that are essential for tumor expansion. Here we examine the involvement of FOXO4 (also known as AFX), a member of the forkhead transcription factor superfamily that is negatively regulated by the PI3K/AKT pathway, in the regulation of HIF-1 alpha protein expression. Nuclear expression of FOXO4 results in the suppression of various responses to hypoxia, including decreased vascular endothelial growth factor, glucose transporter 1, and erythropoietin expression. Interestingly, FOXO4 down-regulates the HIF-1 alpha protein levels, consistent with the lack of hypoxia responsiveness. Previous results have revealed a role for prolyl hydroxylation and resultant von Hippel-Lindau protein (pVHL) interactions in the ubiquitin-proteasome-mediated degradation of HIF-1 alpha. However, neither inhibition of prolyl hydroxylases nor mutation of HIF-1 alpha-hydroxylated prolines involved with pVHL-mediated binding inhibits the observed FOXO4-mediated down-regulation of HIF-1 alpha. These results suggest a novel alternate mechanism for hypoxic regulation that is dependent upon the level of activation of FOXO4-mediated transcription.
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Affiliation(s)
- Tracy Tzu-Ling Tang
- Department of Molecular Oncology, Genentech, Inc., South San Francisco, California 94080, USA
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331
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Masson N, Ratcliffe PJ. HIF prolyl and asparaginyl hydroxylases in the biological response to intracellular O(2) levels. J Cell Sci 2003; 116:3041-9. [PMID: 12829734 DOI: 10.1242/jcs.00655] [Citation(s) in RCA: 171] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Hypoxia-inducible factor (HIF) is a heterodimeric transcription factor that plays a crucial role in mediating cellular responses to oxygen. Oxygen availability influences multiple steps in HIF activation and recent studies have indicated that at least two steps in this process are governed by a novel mode of signal transduction involving enzymatic hydroxylation of specific amino acid residues in HIF-alpha subunits by a series of 2-oxoglutarate (2-OG)-dependent oxygenases. These enzymes are non-haem iron enzymes that use dioxygen in the hydroxylation reaction and therefore provide a direct link between the availability of molecular oxygen and regulation of HIF. Prolyl hydroxylation regulates proteolytic destruction of HIF-alpha by the von Hippel-Lindau ubiquitin ligase complex, whereas HIF-alpha asparaginyl hydroxylation regulates recruitment of transcriptional coactivators. The involvement of at least two distinct types of 2-OG-dependent oxygenase in oxygen-regulated transcription suggests that these enzymes may be well suited to a role in cellular oxygen sensing.
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Affiliation(s)
- Norma Masson
- The Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, UK
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332
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Brugarolas JB, Vazquez F, Reddy A, Sellers WR, Kaelin WG. TSC2 regulates VEGF through mTOR-dependent and -independent pathways. Cancer Cell 2003; 4:147-58. [PMID: 12957289 DOI: 10.1016/s1535-6108(03)00187-9] [Citation(s) in RCA: 406] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Inactivation of the TSC2 tumor suppressor protein causes tuberous sclerosis complex (TSC), a disease characterized by highly vascular tumors. TSC2 has multiple functions including inhibition of mTOR (mammalian target of Rapamycin). We found that TSC2 regulates VEGF through mTOR-dependent and -independent pathways. TSC2 loss results in the accumulation of HIF-1alpha and increased expression of HIF-responsive genes including VEGF. Wild-type TSC2, but not a disease-associated TSC2 mutant, downregulates HIF. Rapamycin normalizes HIF levels in TSC2(-/-) cells, indicating that TSC2 regulates HIF by inhibiting mTOR. In contrast, Rapamycin only partially downregulates VEGF in this setting, implying an mTOR-independent link between TSC2 loss and VEGF. This pathway may involve chromatin remodeling since the HDAC inhibitor Trichostatin A downregulates VEGF in TSC2(-/-) cells.
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Affiliation(s)
- James B Brugarolas
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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333
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Abstract
The recognition of hereditary forms of renal cancer and the development of high-throughput genetic analysis have led to the identification of genes responsible for familial renal epithelial tumors of differing histologies and cytogenetic features. Some of these genes (VHL) are known to have an important role in sporadic renal neoplasia. This article describes the various epithelial renal tumors most commonly encountered by the urologist, the molecular and cytogenetic distinctions between them, and the hereditary syndromes that predispose to these tumors. Consideration of these syndromes is important for proper treatment when one encounters patients with multiple renal tumors, tumors at an early age of onset, or patients with a positive family history of renal cell carcinoma.
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Affiliation(s)
- Christian P Pavlovich
- James Buchanan Brady Urological Institute, A-345 Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224, USA.
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334
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Abstract
von Hippel-Lindau disease is a heritable multisystem cancer syndrome that is associated with a germline mutation of the VHL tumour suppressor gene on the short arm of chromosome 3. This disorder is not rare (about one in 36000 livebirths) and is inherited as a highly penetrant autosomal dominant trait (ie, with a high individual risk of disease). Affected individuals are at risk of developing various benign and malignant tumours of the central nervous system, kidneys, adrenal glands, pancreas, and reproductive adnexal organs. Because of the complexities associated with management of the various types of tumours in this disease, treatment is multidisciplinary. We present an overview of the clinical aspects, management, and treatment options for von Hippel-Lindau disease.
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Affiliation(s)
- Russell R Lonser
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1414, USA.
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335
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Abstract
We studied families with multiple members affected with renal cancer to delineate clinically distinct forms of inherited renal cancer, and to identify and characterize the genes responsible for these disorders. Today, cancer geneticists recognize seven clinically distinct, inherited forms of epithelial renal cancer; genes responsible for five inherited predispositions have been found. Positional cloning efforts for one kidney cancer gene are nearing completion. These discoveries will provide diagnostic tests for these diseases, a foundation for studies of the relationship between genotype and phenotype, and a basis for studies of the pathophysiology of the diverse types of epithelial renal cancer.
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Affiliation(s)
- Berton Zbar
- Laboratory of Immunobiology, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA.
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336
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337
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Abstract
The regulation of angiogenesis by hypoxia is an important component of homeostatic mechanisms that link vascular oxygen supply to metabolic demand. Molecular characterization of angiogenic pathways, identification of hypoxia-inducible factor (HIF) as a key transcriptional regulator of these molecules, and the definition of the HIF hydoxylases as a family of dioxygenases that regulate HIF in accordance with oxygen availability have provided new insights into this process. Here we review these findings, and the role of HIF in developmental, adaptive and neoplastic angiogenesis. We also discuss the implications of oncogenic activation of extensive, physiologically interconnected hypoxia pathways for the tumor phenotype.
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Affiliation(s)
- Christopher W Pugh
- The Henry Wellcome Building of Genomic Medicine, Roosevelt Drive, Oxford, OX3 7BN, UK
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338
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Affiliation(s)
- L Eric Huang
- Laboratory of Human Carcinogenesis, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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339
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Affiliation(s)
- Michal Safran
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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340
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341
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Abstract
This article reviews the recent progress in the search for new treatments for renal cell cancer (RCC), based on a variety of preclinical models or strategies. Some recent clinical trials addressing migrating treatments from other cancers onto RCC and novel agents are discussed, as well as the molecular targets for some of the novel agents. Drugs oriented to histologically definable RCC features, such as the G250 antigen, and the receptor tyrosine kinases, such as epidermal growth factor receptor, are reviewed. Drugs aimed at antiangiogenesis and perturbing features of the cell cycle are also mentioned, including preclinical and empirical experience. Molecular techniques in the study of von Hippel Lindau-related pathways and mRNA expression analyses are cited. Within the immune model of therapy, progress in the application of immune-related drugs including older cytokines (IL-2, IFN-alpha) and of newer cytokine-variant and other cytokines are discussed. Finally, cell-based therapies such as lymphocyte infusions, tumour-cell vaccines, dendritic cell vaccines and allogeneic mini-transplant are outlined. Although high percentage improvements in outcomes for metastatic RCC are not yet realised, the many fronts for scientific and clinical advances form some basis for optimism in the coming years.
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Affiliation(s)
- Mayer Fishman
- H. Lee Moffitt Cancer Center & Research Institute, University of South Florida, MCC 4035, 12902 Magnolia Drive, Tampa, FL 33612, USA.
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342
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Pennacchietti S, Michieli P, Galluzzo M, Mazzone M, Giordano S, Comoglio PM. Hypoxia promotes invasive growth by transcriptional activation of the met protooncogene. Cancer Cell 2003; 3:347-61. [PMID: 12726861 DOI: 10.1016/s1535-6108(03)00085-0] [Citation(s) in RCA: 993] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Hypoxia unleashes the invasive and metastatic potential of tumor cells by largely unknown mechanisms. The Met tyrosine kinase, a high affinity receptor for hepatocyte growth factor (HGF), plays a crucial role in controlling invasive growth and is often overexpressed in cancer. Here we show that: (1) hypoxia activates transcription of the met protooncogene, resulting in higher levels of Met; (2) hypoxic areas of tumors overexpress Met; (3) hypoxia amplifies HGF signaling; (4) hypoxia synergizes with HGF in inducing invasion; (5) the proinvasive effects of hypoxia are mimicked by Met overexpression; and (6) inhibition of Met expression prevents hypoxia-induced invasive growth. These data show that hypoxia promotes tumor invasion by sensitizing cells to HGF stimulation, providing a molecular basis to explain Met overexpression in cancer.
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Affiliation(s)
- Selma Pennacchietti
- Division of Molecular Oncology, Institute for Cancer Research and Treatment, University of Torino Medical School, Candiolo, Italy
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343
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Maynard MA, Qi H, Chung J, Lee EHL, Kondo Y, Hara S, Conaway RC, Conaway JW, Ohh M. Multiple splice variants of the human HIF-3 alpha locus are targets of the von Hippel-Lindau E3 ubiquitin ligase complex. J Biol Chem 2003; 278:11032-40. [PMID: 12538644 DOI: 10.1074/jbc.m208681200] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Functional inactivation of the von Hippel-Lindau (VHL) tumor suppressor protein is the cause of familial VHL disease and sporadic kidney cancer. The VHL gene product (pVHL) is a component of an E3 ubiquitin ligase complex that targets the hypoxia-inducible factor (HIF) 1 and 2 alpha subunits for polyubiquitylation. This process is dependent on the hydroxylation of conserved proline residues on the alpha subunits of HIF-1/2 in the presence of oxygen. In our effort to identify orphan HIF-like proteins in the data base that are potential targets of the pVHL complex, we report multiple splice variants of the human HIF-3 alpha locus as follows: hHIF-3 alpha 1, hHIF-3 alpha 2 (also referred to as hIPAS; human inhibitory PAS domain protein), hHIF-3 alpha 3, hHIF-3 alpha 4, hHIF-3 alpha 5, and hHIF-3 alpha 6. We demonstrate that the common oxygen-dependent degradation domain of hHIF-3 alpha 1-3 splice variants is targeted for ubiquitylation by the pVHL complex in vitro and in vivo. This activity is enhanced in the presence of prolyl hydroxylase and is dependent on a proline residue at position 490. Furthermore, the ubiquitin conjugation occurs on lysine residues at position 465 and 568 within the oxygen-dependent degradation domain. These results demonstrate additional targets of the pVHL complex and suggest a growing complexity in the regulation of hypoxia-inducible genes by the HIF family of transcription factors.
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Affiliation(s)
- Mindy A Maynard
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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344
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Safran M, Kaelin WG. HIF hydroxylation and the mammalian oxygen-sensing pathway. J Clin Invest 2003; 111:779-83. [PMID: 12639980 PMCID: PMC153778 DOI: 10.1172/jci18181] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Michal Safran
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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345
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Kim W, Kaelin WG. The von Hippel-Lindau tumor suppressor protein: new insights into oxygen sensing and cancer. Curr Opin Genet Dev 2003; 13:55-60. [PMID: 12573436 DOI: 10.1016/s0959-437x(02)00010-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The von Hippel-Lindau tumor suppressor protein (pVHL) is the substrate-recognition module of an E3 ubiquitin ligase that targets the alpha subunits of hypoxia-inducible factor (HIF) for degradation in the presence of oxygen. Recognition of HIF by pVHL is linked to enzymatic hydroxylation of conserved prolyl residues in the HIF alpha subunits by members of the EGLN family. Dysregulation of HIF-target genes such as vascular endothelial growth factor and transforming growth factor alpha has been implicated in the pathogenesis of renal cell carcinomas and of hemangioblastomas, both of which frequently lack pVHL function.
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Affiliation(s)
- William Kim
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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346
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Mack FA, Rathmell WK, Arsham AM, Gnarra J, Keith B, Simon MC. Loss of pVHL is sufficient to cause HIF dysregulation in primary cells but does not promote tumor growth. Cancer Cell 2003; 3:75-88. [PMID: 12559177 PMCID: PMC4120823 DOI: 10.1016/s1535-6108(02)00240-4] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Inactivation of the von Hippel-Lindau (VHL) gene is associated with the development of highly vascularized tumors. pVHL targets the alpha subunits of hypoxia inducible factor (HIF) for ubiquitin-mediated degradation in an oxygen-dependent manner. Although pVHL-deficient tumor cell lines demonstrate constitutive stabilization and activation of HIF, it has yet to be shown that loss of murine Vhl alone is sufficient to dysregulate HIF. We utilized a genetic approach to demonstrate that loss of Vhl is sufficient not only to stabilize HIF-alpha subunits under normoxia, but also fully activate HIF-mediated responses. These studies have implications for the hierarchy of signaling events leading to HIF stabilization, nuclear translocation, and target gene expression. We further demonstrate that loss of murine Vhl does not promote teratocarcinoma growth, indicating that other genetic changes must occur to facilitate Vhl-mediated tumorigenesis.
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Affiliation(s)
- Fiona A. Mack
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - W. Kimryn Rathmell
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Andrew M. Arsham
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
- Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - James Gnarra
- Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans, LA 70112
| | - Brian Keith
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - M. Celeste Simon
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
- Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
- Correspondence: M. Celeste Simon, Howard Hughes Medical Institute, Abramson Family Cancer Research Institute, BRB II/III Rm. 456, 421 Curie Blvd., Philadelphia, PA 19104, TEL: 215-746-5562, FAX: 215-746-5532,
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347
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Affiliation(s)
- Michael Zimmer
- Massachusetts General Hospital Cancer Center, MGH Familial Renal Cancer Clinic, Harvard Medical School, Boston, MA, USA
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348
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Abstract
Molecular oxygen (O2)is a basic requirement for cellular growth and viability and many aspects of anatomy and physiology are dedicated to achieving reliable distribution. Recent work has identified a specific sensing and response system, centred around a transcription complex called Hypoxia-inducible Factor 1 (HIF-1), which forms the focus of this review. The HIF-system operates in all cell types and modulates a very broad range of cellular pathways, consistent with the broad importance of oxygen. It is implicated in a rapidly expanding range of developmental, physiological and pathological settings, and is potentially relevant to almost all areas of clinical medicine. Excitingly, the pathway can be activated with low molecular weight compounds which should offer therapeutic benefit, especially in diseases where oxygen supply is compromised.
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349
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Zhou MI, Wang H, Ross JJ, Kuzmin I, Xu C, Cohen HT. The von Hippel-Lindau tumor suppressor stabilizes novel plant homeodomain protein Jade-1. J Biol Chem 2002; 277:39887-98. [PMID: 12169691 DOI: 10.1074/jbc.m205040200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The von Hippel-Lindau disease gene (VHL) is the causative gene for most adult renal cancers. However, the mechanism by which VHL protein functions as a renal tumor suppressor remains largely unknown. To identify low occupancy VHL protein partners with potential relevance to renal cancer, we screened a human kidney library against human VHL p30 using a yeast two-hybrid approach. Jade-1 (gene for Apoptosis and Differentiation in Epithelia) encodes a previously uncharacterized 64-kDa protein that interacts strongly with VHL protein and is most highly expressed in kidney. Jade-1 protein is short-lived and contains a candidate destabilizing (PEST) motif and plant homeodomains that are not required for the VHL interaction. Jade-1 is abundant in proximal tubule cells, which are clear-cell renal cancer precursors, and expression increases with differentiation. Jade-1 is expressed in cytoplasm and the nucleus diffusely and in speckles, where it partly colocalizes with VHL. VHL reintroduction into renal cancer cells increases endogenous Jade-1 protein abundance up to 10-fold. Furthermore, VHL increases Jade-1 protein half-life up to 3-fold. Thus, direct protein stabilization is identified as a new VHL function. Moreover, Jade-1 protein represents a novel candidate regulatory factor in VHL-mediated renal tumor suppression.
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Affiliation(s)
- Mina I Zhou
- Department of Medicine, Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts 02118, USA
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350
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Abstract
The von Hippel-Lindau hereditary cancer syndrome was first described about 100 years ago. The unusual clinical features of this disorder predicted a role for the von Hippel-Lindau gene (VHL) in the oxygen-sensing pathway. Indeed, recent studies of this gene have helped to decipher how cells sense changes in oxygen availability, and have revealed a previously unappreciated role of prolyl hydroxylation in intracellular signalling. These studies, in turn, are laying the foundation for the treatment of a diverse set of disorders, including cancer, myocardial infarction and stroke.
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Affiliation(s)
- William G Kaelin
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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