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Taohong Siwu-Containing Serum Enhances Angiogenesis in Rat Aortic Endothelial Cells by Regulating the VHL/HIF-1 α/VEGF Signaling Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:6610116. [PMID: 34853600 PMCID: PMC8629617 DOI: 10.1155/2021/6610116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 07/27/2021] [Accepted: 10/01/2021] [Indexed: 01/15/2023]
Abstract
Background The incidence of bone fracture and bone-related diseases is increasing every year. Angiogenesis plays a vital role in fracture healing and bone repair. This study assessed the benefits of Taohong Siwu (TSW) decoction on angiogenesis in isolated rat aortic endothelial cells (RAEC) treated with TSW-containing serum. Methods The components of TSW decoction were analyzed by liquid chromatography-mass spectrometry (LC-MS). TSW-containing serum was prepared by gavage of TSW decoction to Sprague-Dawley (SD) rats. The effects of TSW-containing serum on the viability, migration, wound healing, and angiogenesis of RAEC were detected by the MTT, transwell, wound healing, and Matrigel lumen formation assays, respectively. In addition, the effects of an HIF-1α inhibitor on TSW-containing serum-induced RAEC were also assessed. The effects of TSW-containing serum on the expression of the HIF-1α signaling pathway were evaluated by qRT-PCR and western blot analysis. Results LC-MS revealed that TSW decoction primarily contained isomaltulose, choline, D-gluconic acid, L-pipecolic acid, hypotaurine, albiflorin, and tryptophan. TSW-containing serum significantly increased the viability, migration, wound healing, and angiogenesis of RAEC in a dose-dependent manner. Furthermore, our results demonstrated that HIF-1α and VEGF expressions were increased in the cells of TSW-containing serum groups, whereas VHL expression was decreased. The effects of TSW-containing serum were reversed by treatment with an HIF-1α inhibitor. Conclusion These results suggested that TSW decoction enhanced angiogenesis by regulating the VHL/HIF-1α/VEGF signaling pathway.
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2
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Todd VM, Vecchi LA, Clements ME, Snow KP, Ontko CD, Himmel L, Pinelli C, Rafat M, Johnson RW. Hypoxia inducible factor signaling in breast tumors controls spontaneous tumor dissemination in a site-specific manner. Commun Biol 2021; 4:1122. [PMID: 34556788 PMCID: PMC8460839 DOI: 10.1038/s42003-021-02648-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 09/08/2021] [Indexed: 02/07/2023] Open
Abstract
Hypoxia is a common feature in tumors and induces signaling that promotes tumor cell survival, invasion, and metastasis, but the impact of hypoxia inducible factor (HIF) signaling in the primary tumor on dissemination to bone in particular remains unclear. To better understand the contributions of hypoxia inducible factor 1 alpha (HIF1α), HIF2α, and general HIF pathway activation in metastasis, we employ a PyMT-driven spontaneous murine mammary carcinoma model with mammary specific deletion of Hif1α, Hif2α, or von Hippel-Lindau factor (Vhl) using the Cre-lox system. Here we show that Hif1α or Hif2α deletion in the primary tumor decreases metastatic tumor burden in the bone marrow, while Vhl deletion increases bone tumor burden, as hypothesized. Unexpectedly, Hif1α deletion increases metastatic tumor burden in the lung, while deletion of Hif2α or Vhl does not affect pulmonary metastasis. Mice with Hif1α deleted tumors also exhibit reduced bone volume as measured by micro computed tomography, suggesting that disruption of the osteogenic niche may be involved in the preference for lung dissemination observed in this group. Thus, we reveal that HIF signaling in breast tumors controls tumor dissemination in a site-specific manner.
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Affiliation(s)
- Vera M Todd
- Graduate Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, TN, USA
| | - Lawrence A Vecchi
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, TN, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Miranda E Clements
- Tumor Microenvironment and Metastasis Section, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Katherine P Snow
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, TN, USA
- Department of Medicine, Health, and Society, Vanderbilt University, Nashville, TN, USA
| | - Cayla D Ontko
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Lauren Himmel
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Christopher Pinelli
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Marjan Rafat
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, TN, USA
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Rachelle W Johnson
- Graduate Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA.
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, TN, USA.
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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3
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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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Pal K, Madamsetty VS, Dutta SK, Wang E, Angom RS, Mukhopadhyay D. Synchronous inhibition of mTOR and VEGF/NRP1 axis impedes tumor growth and metastasis in renal cancer. NPJ Precis Oncol 2019; 3:31. [PMID: 31840081 PMCID: PMC6895165 DOI: 10.1038/s41698-019-0105-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 10/17/2019] [Indexed: 12/11/2022] Open
Abstract
Clear cell renal cell carcinoma (ccRCC) is known for its highly vascular phenotype which is associated with elevated expression of vascular endothelial growth factor A (VEGF), also known as vascular permeability factor (VPF). Accordingly, VEGF has been an attractive target for antiangiogenic therapies in ccRCC. Two major strategies have hitherto been utilized for VEGF-targeted antiangiogenic therapies: targeting VEGF by antibodies, ligand traps or aptamers, and targeting the VEGF receptor signaling via antibodies or small-molecule tyrosine-kinase inhibitors (TKIs). In the present article we utilized two entirely different approaches: targeting mammalian target of rapamycin (mTOR) pathway that is known to be involved in VEGF synthesis, and disruption of VEGF/Neuroplin-1 (NRP1) axis that is known to activate proangiogenic and pro-tumorigenic signaling in endothelial and tumor cells, respectively. Everolimus (E) and a small-molecule inhibitor EG00229 (G) were used for the inhibition of mTOR and the disruption of VEGF/NRP1 axis, respectively. We also exploited a liposomal formulation decorated with a proprietary tumor-targeting-peptide (TTP) to simultaneously deliver these two agents in a tumor-targeted manner. The TTP-liposomes encapsulating both Everolimus and EG00229 (EG-L) demonstrated higher in vitro and in vivo growth retardation than the single drug-loaded liposomes (E-L and G-L) in two different ccRCC models and led to a noticeable reduction in lung metastasis in vivo. In addition, EG-L displayed remarkable inhibition of tumor growth in a highly aggressive syngeneic immune-competent mouse model of ccRCC developed in Balb/c mice. Taken together, this study demonstrates an effective approach to achieve improved therapeutic outcome in ccRCC.
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Affiliation(s)
- Krishnendu Pal
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
| | - Vijay Sagar Madamsetty
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
| | - Shamit Kumar Dutta
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
| | - Enfeng Wang
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
| | - Ramcharan Singh Angom
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
| | - Debabrata Mukhopadhyay
- Department of Biochemistry and Molecular Biology, Mayo Clinic Florida, 4500 San Pablo Road S, Jacksonville, FL 32224 USA
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5
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Zhang H, Okamoto M, Panzhinskiy E, Zawada WM, Das M. PKCδ/midkine pathway drives hypoxia-induced proliferation and differentiation of human lung epithelial cells. Am J Physiol Cell Physiol 2014; 306:C648-58. [PMID: 24500281 PMCID: PMC3962599 DOI: 10.1152/ajpcell.00351.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/30/2014] [Indexed: 12/13/2022]
Abstract
Epithelial cells are key players in the pathobiology of numerous hypoxia-induced lung diseases. The mechanisms mediating such hypoxic responses of epithelial cells are not well characterized. Earlier studies reported that hypoxia stimulates protein kinase C (PKC)δ activation in renal cancer cells and an increase in expression of a heparin-binding growth factor, midkine (MK), in lung alveolar epithelial cells. We reasoned that hypoxia might regulate MK levels via a PKCδ-dependent pathway and hypothesized that PKCδ-driven MK expression is required for hypoxia-induced lung epithelial cell proliferation and differentiation. Replication of human lung epithelial cells (A549) was significantly increased by chronic hypoxia (1% O2) and was dependent on expression of PKCδ. Hypoxia-induced proliferation of epithelial cells was accompanied by translocation of PKCδ from Golgi into the nuclei. Marked attenuation in MK protein levels by rottlerin, a pharmacological antagonist of PKC, and by small interfering RNA-targeting PKCδ, revealed that PKCδ is required for MK expression in both normoxic and hypoxic lung epithelial cells. Sequestering MK secreted into the culture media with a neutralizing antibody reduced hypoxia-induced proliferation demonstrating that an increase in MK release from cells is linked with epithelial cell division under hypoxia. In addition, recombinant MK accelerated transition of hypoxic epithelial cells to cells of mesenchymal phenotype characterized by elongated morphology and increased expression of mesenchymal markers, α-smooth muscle actin, and vimentin. We conclude that PKCδ/MK axis mediates hypoxic proliferation and differentiation of lung epithelial cells. Manipulation of PKCδ and MK activity in epithelial cells might be beneficial for the treatment of hypoxia-mediated lung diseases.
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Affiliation(s)
- Hanying Zhang
- Department of Animal Sciences, University of Wyoming, Laramie, Wyoming
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6
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Zhang Q, Yang H. The Roles of VHL-Dependent Ubiquitination in Signaling and Cancer. Front Oncol 2012; 2:35. [PMID: 22649785 PMCID: PMC3355907 DOI: 10.3389/fonc.2012.00035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 03/26/2012] [Indexed: 01/07/2023] Open
Abstract
The function of tumor suppressor VHL is compromised in the vast majority of clear cell renal cell carcinoma, and its mutations or loss of expression was causal for this disease. pVHL was found to be a substrate recognition subunit of an E3 ubiquitin ligase, and most of the tumor-derived mutations disrupt this function. pVHL was found to bind to the alpha subunits of hypoxia-inducible factor (HIF) and promote their ubiquitination and proteasomal degradation. Proline hydroxylation on key sites of HIFα provides the binding signal for pVHL E3 ligase complex. Beside HIFα, several other VHL targets have been identified, including activated epidermal growth factor receptor (EGFR), RNA polymerase II subunits RPB1 and hsRPB7, atypical protein kinase C (PKC), Sprouty2, β-adrenergic receptor II, and Myb-binding protein p160. HIFα is the most well studied substrate and has been proven to be critical for pVHL's tumor suppressor function, but the activated EGFR and PKC and other pVHL substrates might also be important for tumor growth and drug response. Their regulations by pVHL and their relevance to signaling and cancer are discussed.
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Affiliation(s)
- Qing Zhang
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School Boston, MA, USA
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7
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Iyer S, Acharya KR. Tying the knot: the cystine signature and molecular-recognition processes of the vascular endothelial growth factor family of angiogenic cytokines. FEBS J 2011; 278:4304-22. [PMID: 21917115 PMCID: PMC3328748 DOI: 10.1111/j.1742-4658.2011.08350.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The cystine-knot motif, made up of three intertwined disulfide bridges, is a unique feature of several toxins, cyclotides and growth factors, and occurs in a variety of species, including fungi, insects, molluscs and mammals. Growth factor molecules containing the cystine-knot motif serve as ligands for a diverse range of receptors and play an important role in extracellular signalling. This superfamily of polypeptides comprises several homodimeric and heterodimeric molecules that are central characters in both health and disease. Amongst these molecules are a group of proteins that belong to the vascular endothelial growth factor (VEGF) subfamily. The members of this family are known angiogenic factors that regulate processes leading to blood vessel formation in physiological and pathological conditions. The focus of the present review is on the structural characteristics of proteins that belong to the VEGF family and on signal-transduction pathways that become initiated via the VEGF receptors.
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Affiliation(s)
- Shalini Iyer
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, UK
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8
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Payne SJL, Jones L. Influence of the tumor microenvironment on angiogenesis. Future Oncol 2011; 7:395-408. [PMID: 21417903 DOI: 10.2217/fon.11.13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
It is becoming increasingly recognized that the host microenvironment is essential for regulating tumor cell behavior. The cellular stromal compartment can modulate angiogenesis either directly through enhanced secretion of pro-angiogenic factors or reduced secretion of antiangiogenic factors, or indirectly by modulating the surrounding extracellular matrix. Control of angiogenesis represents a critical step in cancer progression and is a potential therapeutic target. This article focuses on the role of the tumor microenvironment in the control of angiogenesis and how dissection of the molecular interactions may enhance prognostic and predictive power and facilitate therapeutic targeting.
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Affiliation(s)
- Sarah J L Payne
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK.
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9
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VHL loss in renal cell carcinoma leads to up-regulation of CUB domain-containing protein 1 to stimulate PKC{delta}-driven migration. Proc Natl Acad Sci U S A 2011; 108:1931-6. [PMID: 21233420 DOI: 10.1073/pnas.1011777108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A common genetic mutation found in clear cell renal cell carcinoma (CC-RCC) is the loss of the von Hippel-Lindau (VHL) gene, which results in stabilization of hypoxia-inducible factors (HIFs), and contributes to cancer progression and metastasis. CUB-domain-containing protein 1 (CDCP1) was shown to promote metastasis in scirrhous and lung adenocarcinomas as well as in prostate cancer. In this study, we established a molecular mechanism linking VHL loss to induction of the CDCP1 gene through the HIF-1/2 pathway in renal cancer. Also, we report that Fyn, which forms a complex with CDCP1 and mediates its signaling to PKCδ, is a HIF-1 target gene. Mechanistically, we found that CDCP1 specifically regulates phosphorylation of PKCδ, but not of focal adhesion kinase or Crk-associated substrate. Signal transduction from CDCP1 to PKCδ leads to its activation, increasing migration of CC-RCC. Furthermore, patient survival can be stratified by CDCP1 expression at the cell surface of the tumor. Taken together, our data indicates that CDCP1 protein might serve as a therapeutic target for CC-RCC.
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10
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Haase VH. The VHL tumor suppressor: master regulator of HIF. Curr Pharm Des 2010; 15:3895-903. [PMID: 19671042 DOI: 10.2174/138161209789649394] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 07/01/2009] [Indexed: 12/11/2022]
Abstract
Hypoxia-Inducible Factors (HIFs) are heterodimeric oxygen-sensitive basic helix-loop-helix transcription factors that play central roles in cellular adaptation to low oxygen environments. The von-Hippel Lindau tumor suppressor (pVHL) is the substrate recognition component of an E3 ubiquitin ligase and functions as a master regulator of HIF activity by targeting the hydroxylated HIF-alpha subunit for ubiquitylation and rapid proteasomal degradation under normoxic conditions. Mutations in pVHL can be found in familial and sporadic hemangioblastomas, clear cell carcinomas of the kidney, pheochromocytomas and inherited forms of erythrocytosis, illustrating the importance of disrupted molecular oxygen sensing in the pathogenesis of these diseases. Tissue-specific gene targeting of pVHL in mice has demonstrated that efficient execution of HIF proteolysis is critically important for normal tissue physiology, and has provided novel insights into the functional consequences of HIF activation on the cellular and tissue level. Here we focus on the contribution of individual HIF transcription factors to the development of VHL phenotypes and discuss how the pVHL/HIF axis could be exploited pharmacologically.
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Affiliation(s)
- Volker H Haase
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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11
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Shen HCJ, Adem A, Ylaya K, Wilson A, He M, Lorang D, Hewitt SM, Pechhold K, Harlan DM, Lubensky IA, Schmidt LS, Linehan WM, Libutti SK. Deciphering von Hippel-Lindau (VHL/Vhl)-associated pancreatic manifestations by inactivating Vhl in specific pancreatic cell populations. PLoS One 2009; 4:e4897. [PMID: 19340311 PMCID: PMC2660574 DOI: 10.1371/journal.pone.0004897] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 01/29/2009] [Indexed: 01/15/2023] Open
Abstract
The von Hippel-Lindau (VHL) syndrome is a pleomorphic familial disease characterized by the development of highly vascularized tumors, such as hemangioblastomas of the central nervous system, pheochromocytomas, renal cell carcinomas, cysts and neuroendocrine tumors of the pancreas. Up to 75% of VHL patients are affected by VHL-associated pancreatic lesions; however, very few reports in the published literature have described the cellular origins and biological roles of VHL in the pancreas. Since homozygous loss of Vhl in mice resulted in embryonic lethality, this study aimed to characterize the functional significance of VHL in the pancreas by conditionally inactivating Vhl utilizing the Cre/LoxP system. Specifically, Vhl was inactivated in different pancreatic cell populations distinguished by their roles during embryonic organ development and their endocrine lineage commitment. With Cre recombinase expression directed by a glucagon promoter in alpha-cells or an insulin promoter in beta-cells, we showed that deletion of Vhl is dispensable for normal functions of the endocrine pancreas. In addition, deficiency of VHL protein (pVHL) in terminally differentiated alpha-cells or beta-cells is insufficient to induce pancreatic neuroendocrine tumorigenesis. Most significantly, we presented the first mouse model of VHL-associated pancreatic disease in mice lacking pVHL utilizing Pdx1-Cre transgenic mice to inactivate Vhl in pancreatic progenitor cells. The highly vascularized microcystic adenomas and hyperplastic islets that developed in Pdx1-Cre;Vhl f/f homozygous mice exhibited clinical features similar to VHL patients. Establishment of three different, cell-specific Vhl knockouts in the pancreas have allowed us to provide evidence suggesting that VHL is functionally important for postnatal ductal and exocrine pancreas, and that VHL-associated pancreatic lesions are likely to originate from progenitor cells, not mature endocrine cells. The novel model systems reported here will provide the basis for further functional and genetic studies to define molecular mechanisms involved in VHL-associated pancreatic diseases.
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Affiliation(s)
- H.-C. Jennifer Shen
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Asha Adem
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Kris Ylaya
- Tissue Array Research Program, Laboratory of Pathology, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Arianne Wilson
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Mei He
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Dominique Lorang
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Stephen M. Hewitt
- Tissue Array Research Program, Laboratory of Pathology, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Klaus Pechhold
- Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States of America
| | - David M. Harlan
- Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States of America
| | - Irina A. Lubensky
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Rockville, Maryland, United States of America
| | - Laura S. Schmidt
- Urologic Oncology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
- Basic Research Program, Science Applications International Corporation (SAIC)-Frederick, Inc., National Cancer Institute-Frederick, Frederick, Maryland, United States of America
| | - W. Marston Linehan
- Urologic Oncology Branch, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Steven K. Libutti
- Tumor Angiogenesis Section, Surgery Branch, National Cancer Institute, Bethesda, Maryland, United States of America
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12
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Feijóo-Cuaresma M, Méndez F, Maqueda A, Esteban MA, Naranjo-Suarez S, Castellanos MC, del Cerro MH, Vazquez SN, García-Pardo A, Landázuri MO, Calzada MJ. Inadequate activation of the GTPase RhoA contributes to the lack of fibronectin matrix assembly in von Hippel-Lindau protein-defective renal cancer cells. J Biol Chem 2008; 283:24982-90. [PMID: 18567581 PMCID: PMC2529126 DOI: 10.1074/jbc.m709390200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 04/28/2008] [Indexed: 11/24/2022] Open
Abstract
The von Hippel-Lindau (VHL) tumor suppressor gene regulates extracellular matrix deposition. In VHL negative renal cancer cells, VHL(-), the lack of fibronectin matrix assembly is thought to promote and maintain tumor angiogenesis allowing vessels to infiltrate tumors. Therefore, and considering the importance of this process in tumor growth, we aimed to study why VHL(-) renal cancer cells fail to form a proper extracellular matrix. Our results showed that VHL(-) cells were not defective in fibronectin production and that the fibronectin produced by these cells was equally functional in promoting cell adhesion and matrix assembly as that produced by VHL+ cells. We have previously reported that VHL(-) cells fail to form beta1 integrin fibrillar adhesions and have a diminished organization of actin stress fibers; therefore, we aimed to study if the small GTPase family is involved in this process. We found that activation of the RhoA GTPase was defective in VHL(-) cells, and this was possibly mediated by an increased activation of its inhibitor, p190RhoGAP. Additionally, the expression of constitutively active RhoA in VHL(-) cells resulted in formation of a fibronectin matrix. These results strongly suggest an important role for RhoA in some of the defects observed in renal cancer cells.
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Affiliation(s)
- Monica Feijóo-Cuaresma
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Fernando Méndez
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Alfredo Maqueda
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Miguel A. Esteban
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Salvador Naranjo-Suarez
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Maria C. Castellanos
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Mercedes Hernández del Cerro
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Silvia N. Vazquez
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Angeles García-Pardo
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Manuel O. Landázuri
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
| | - Maria J. Calzada
- Servicio de
Inmunología, Hospital de la Princesa, Departamento de Medicina,
Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid,
Spain, the Departamento de
Fisiopatología Celular y Molecular, Centro de Investigaciones
Biológicas, CSIC, 28040 Madrid, Spain, and the
Guangzhou Institute of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510663, China
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13
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Basu A, Contreras AG, Datta D, Flynn E, Zeng L, Cohen HT, Briscoe DM, Pal S. Overexpression of vascular endothelial growth factor and the development of post-transplantation cancer. Cancer Res 2008; 68:5689-98. [PMID: 18632621 DOI: 10.1158/0008-5472.can-07-6603] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cancer is an increasing and major problem after solid organ transplantation. In part, the increased cancer risk is associated with the use of immunosuppressive agents, especially calcineurin inhibitors. We propose that the effect of calcineurin inhibitors on the expression of vascular endothelial growth factor (VEGF) leads to an angiogenic milieu that favors tumor growth. Here, we used 786-0 human renal cancer cells to investigate the effect of cyclosporine (CsA) on VEGF expression. Using a full-length VEGF promoter-luciferase construct, we found that CsA markedly induced VEGF transcriptional activation through the protein kinase C (PKC) signaling pathway, specifically involving PKC zeta and PKC delta isoforms. Moreover, CsA promoted the association of PKC zeta and PKC delta with the transcription factor Sp1 as observed by immunoprecipitation assays. Using promoter deletion constructs, we found that CsA-mediated VEGF transcription was primarily Sp1 dependent. Furthermore, CsA-induced and PKC-Sp1-mediated VEGF transcriptional activation was partially inhibited by von Hippel-Lindau protein. CsA also promoted the progression of human renal tumors in vivo, wherein VEGF is overexpressed. Finally, to evaluate the in vivo significance of CsA-induced VEGF overexpression in terms of post-transplantation tumor development, we injected CT26 murine carcinoma cells (known to form angiogenic tumors) into mice with fully MHC mismatched cardiac transplants. We observed that therapeutic doses of CsA increased tumor size and VEGF mRNA expression and also enhanced tumor angiogenesis. However, coadministration of a blocking anti-VEGF antibody inhibited this CsA-mediated tumor growth. Collectively, these findings define PKC-mediated VEGF transcriptional activation as a key component in the progression of CsA-induced post-transplantation cancer.
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Affiliation(s)
- Aninda Basu
- Division of Nephrology, Children's Hospital Boston, Boston, MA 02115, USA
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14
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Kapitsinou PP, Haase VH. The VHL tumor suppressor and HIF: insights from genetic studies in mice. Cell Death Differ 2008; 15:650-9. [PMID: 18219317 DOI: 10.1038/sj.cdd.4402313] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The von Hippel-Lindau tumor suppressor gene product, pVHL, functions as the substrate recognition component of an E3-ubiquitin ligase, which targets the oxygen-sensitive alpha-subunit of hypoxia-inducible factor (HIF) for rapid proteasomal degradation under normoxic conditions and as such plays a central role in molecular oxygen sensing. Mutations in pVHL can be found in familial and sporadic clear cell carcinomas of the kidney, hemangioblastomas of the retina and central nervous system, and pheochromocytomas, underscoring its gatekeeper function in the pathogenesis of these tumors. Tissue-specific gene targeting of VHL in mice has demonstrated that efficient execution of pVHL-mediated HIF proteolysis under normoxia is fundamentally important for survival, proliferation, differentiation and normal physiology of many cell types, and has provided novel insights into the biological function of individual HIF transcription factors. In this review, we discuss the role of HIF in the development of the VHL phenotype.
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Affiliation(s)
- P P Kapitsinou
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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15
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Wu KL, Miao H, Khan S. JAK kinases promote invasiveness in VHL-mediated renal cell carcinoma by a suppressor of cytokine signaling-regulated, HIF-independent mechanism. Am J Physiol Renal Physiol 2007; 293:F1836-46. [PMID: 17898043 DOI: 10.1152/ajprenal.00096.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
von Hippel-Lindau (VHL) disease is a cancer syndrome, which includes renal cell carcinoma (RCC), and is caused by VHL mutations. Most, but not all VHL phenotypes are due to failure of mutant VHL to regulate constitutive proteolysis of hypoxia-inducible factors (HIFs). Janus kinases (JAK1, 2, 3, and TYK2) promote cell survival and proliferation, processes tightly controlled by SOCS proteins, which have sequence and structural homology to VHL. We hypothesized that in VHL disease, RCC pathogenesis results from enhanced SOCS1 degradation, leading to upregulated JAK activity. We find that baseline JAK2, JAK3, and TYK2 activities are increased in RCC cell lines, even after serum deprivation or coincubation with cytokine inhibitors. Furthermore, JAK activity is sustained in RCC stably expressing HIF2α shRNA. Invasion through Matrigel and migration in wound-healing assays, in vitro correlates of metastasis, are significantly greater in VHL mutant RCC compared with wild-type cells, and blocked by dominant-negative JAK expression or JAK inhibitors. Finally, we observe enhanced SOCS2/SOCS1 coprecipitation and reduced SOCS1 expression due to proteasomal degradation in VHL-null RCC compared with wild-type cells. The data support a new HIF-independent mechanism of RCC metastasis, whereby SOCS2 recruits SOCS1 for ubiquitination and proteasome degradation, which lead to unrestricted JAK-dependent RCC invasion. In addition to commonly proposed RCC treatment strategies that target HIFs, our data suggest that JAK inhibition represents an alternative therapeutic approach.
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Affiliation(s)
- Karen L Wu
- Case Western Reserve Univ., School of Medicine, Dept. of Nutrition, Research Tower, RT600, 2109 Adelbert Rd., Cleveland, OH 44106, USA.
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16
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Podar K, Raab MS, Chauhan D, Anderson KC. The therapeutic role of targeting protein kinase C in solid and hematologic malignancies. Expert Opin Investig Drugs 2007; 16:1693-707. [PMID: 17922632 DOI: 10.1517/13543784.16.10.1693] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The protein kinase C (PKC) family, the most prominent target of tumor-promoting phorbol esters, is functionally linked to cell differentiation, growth, survival, migration and tumorigenesis and so mediates tumor cell proliferation, survival, multidrug resistance, invasion, metastasis and tumor angiogenesis. Therefore, targeting PKC isozymes may represent an attractive target for novel anticancer therapies. Recent preclinical and clinical studies using the macrocyclic bisindolylmaleimide enzastaurin or the N-benzylstaurosporine midostaurin demonstrate promising activity of PKC inhibitors in a variety of tumors, including diffuse large B-cell lymphoma, multiple myeloma and Waldenstroem's macroglobulinemia. However, our knowledge of PKCs in tumorigenesis is still only partial and each PKC isoform may contribute to tumorigenesis in a distinct way. Specifically, PKC isoforms have vastly different roles, which vary depending on expression levels of organ and tissue distribution, cell type, intracellular localization, protein-protein and lipid-protein interactions and the biologic environment. Although PKC activation generally positively affects tumor cell growth, motility, invasion and metastasis, recent reports show that many PKCs can also have negative effects. Therefore, it is necessary to further dissect the relative contribution of PKC isozymes in the development and progression of specific tumors in order to identify therapeutic opportunities, using either PKC inhibitors or PKC activators.
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Affiliation(s)
- Klaus Podar
- Dana-Farber Cancer Institute, Department of Medical Oncology, Jerome Lipper Multiple Myeloma Center, 44 Binney Street, Boston, MA 02115, USA.
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17
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Abstract
Decreased oxygen availability is a common feature during embryonic development as well of malignant tumours. Hypoxia regulates many transcription factors, and one of the most studied is the hypoxia-inducible factor (HIF). As a consequence of HIF stabilisation, the cell constitutively upregulates the hypoxic programme resulting in the expression of genes responsible for global changes in cell proliferation, angiogenesis, metastasis, invasion, de-differentiation and energy metabolism. Of the three known alpha subunits of HIF transcription factors, HIF-1alpha and HIF-2alpha have been the most studied. Their differential expression and function have been widely discussed, however no clear picture has been drawn on how these two transcription factors differently regulate common and unique target genes. Their role as oncogenes has also been suggested in several studies. In this review we provide an overview of the current knowledge on some of the most important aspects of HIFalpha regulation, its role in tumour angiogenesis and energetic metabolism. We also give an overview of how the modulation of HIF regulating pathways is a potential therapeutic target that may have benefits in the treatment of cancer.
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Affiliation(s)
- M J Calzada
- Departamento de Medicina, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
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18
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Abstract
Angiogenesis plays an important role in the growth and progression of cancer. The regulation of tumor angiogenesis depends on a net balance of angiogenic factors and antiangiogenic factors, which are secreted by both tumor cells and host-infiltrating cells. Numerous studies have indicated that assessment of angiogenic activity by either microvessel density or expression of angiogenic factors in cancer can provide prognostic information independent of conventional clinicopathological factors such as tumor staging. Some studies also suggested that assessment of tumor angiogenesis may predict cancer response to chemotherapy or radiotherapy. However, the most important clinical implication of tumor angiogenesis is the development of a novel strategy of anticancer therapy targeting tumor vessels instead of cancer cells. Antiangiogenic therapy aims to inhibit the growth of tumor, and current evidence suggests that it works best in combination with conventional cytotoxic chemotherapy. Recently, a monoclonal antibody against vascular endothelial growth factor, which is one of the most potent angiogenic factors, has been approved for clinical use in colorectal cancer patients after a clinical trial confirmed that combining the antibody with standard chemotherapy regimen could prolong patient survival. The clinical implications of angiogenesis in cancer are reviewed in this article.
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Affiliation(s)
- Roberta WC Pang
- Department of Medicine, The University of Hong KongPokfulam, Hong Kong, China
| | - Ronnie TP Poon
- Department of Surgery, The University of Hong KongPokfulam, Hong Kong, China
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19
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Xia S, Forman LW, Faller DV. Protein kinase C delta is required for survival of cells expressing activated p21RAS. J Biol Chem 2007; 282:13199-210. [PMID: 17350960 PMCID: PMC3527128 DOI: 10.1074/jbc.m610225200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Inhibition of protein kinase C (PKC) activity in transformed cells and tumor cells containing activated p21(RAS) results in apoptosis. To investigate the pro-apoptotic pathway induced by the p21(RAS) oncoprotein, we first identified the specific PKC isozyme necessary to prevent apoptosis in the presence of activated p21(RAS). Dominant-negative mutants of PKC, short interfering RNA vectors, and PKC isozyme-specific chemical inhibitors directed against the PKCdelta isozyme demonstrated that PKCdelta plays a critical role in p21(RAS)-mediated apoptosis. An activating p21(RAS) mutation, or activation of the phosphatidylinositol 3-kinase (PI3K) Ras effector pathway, increased the levels of PKCdelta protein and activity in cells, whereas inhibition of p21(RAS) activity decreased the expression of the PKCdelta protein. Activation of the Akt survival pathway by oncogenic Ras required PKCdelta activity. Akt activity was dramatically decreased after PKCdelta suppression in cells containing activated p21(RAS). Conversely, constitutively activated Akt rescued cells from apoptosis induced by PKCdelta inhibition. Collectively, these findings demonstrate that p21(RAS), through its downstream effector PI3K, induces PKCdelta expression and that this increase in PKCdelta activity, acting through Akt, is required for cell survival. The p21(RAS) effector molecule responsible for the initiation of the apoptotic signal after suppression of PKCdelta activity was also determined to be PI3K. PI3K (p110(C)(AAX), where AA is aliphatic amino acid) was sufficient for induction of apoptosis after PKCdelta inhibition. Thus, the same p21(RAS) effector, PI3K, is responsible for delivering both a pro-apoptotic signal and a survival signal, the latter being mediated by PKCdelta and Akt. Selective suppression of PKCdelta activity and consequent induction of apoptosis is a potential strategy for targeting of tumor cells containing an activated p21(RAS).
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Affiliation(s)
- Shuhua Xia
- Cancer Research Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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20
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Dorai T, Sawczuk I, Pastorek J, Wiernik PH, Dutcher JP. Role of carbonic anhydrases in the progression of renal cell carcinoma subtypes: proposal of a unified hypothesis. Cancer Invest 2007; 24:754-79. [PMID: 17162558 DOI: 10.1080/07357900601062321] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Renal cell carcinoma (RCC) has the highest rate of occurrence within the US when compared with other countries. Recent advances in the basic research and molecular diagnostics of this malignancy have revealed that RCC is not a single disease, but it is a mixture of several types of malignancies with unique molecular mechanisms and pathological attributes. RCC is now divided into clear cell carcinoma (80% of all kidney cancers), papillary type 1 and papillary type 2 neoplasms (10-15% of all RCC patients) and RCC with chromophobic and oncocytic features, called the Birt-Hogg-Dube (BHD) subtype, in roughly 5% of all patients. Apart from these, neoplasms such as the tuberous sclerosis (TSC) syndrome may occur with a mixed pathological features with a renal presentation. In this review, molecular evidence, both direct and indirect, published so far on all these RCC subtypes have been analyzed to find out whether there is any common thread that could run through these disparate malignancies that happen to occur in a single organ, i.e., the kidney. We believe that the role played by the expression and certain non-traditional activities of the cabonic anhydrase (CA) family members, along with the differing levels of hypoxia induced within these tumors may be the most common denominators. Evidence is presented focusing on how the CA family members could participate in the genesis and progression of each and every one of these RCC subtypes and how their function could be influenced by hypoxia, activities of receptor type protein tyrosine kinases and certain other pre-disposing factors. These rationalizations point towards a unified hypothesis that may help explain the occurrence of all these RCC subtypes in a molecular manner. We hope that these analyses would a) stimulate further studies aimed toward a better understanding of the role played by carbonic anhydrases in RCC subtypes and b) would pave way to a better and rationally designed therapies to interfere with their function to benefit patients with RCC and possibly other cancers.
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Affiliation(s)
- Thambi Dorai
- Comprehensive Cancer Center, Our Lady of Mercy Medical Center, New York Medical College, Bronx, New York 10466, USA.
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21
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Affiliation(s)
- William G. Kaelin
- Department of Medical Oncology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Howard Hughes Medical Institute, Chevy Chase, Maryland 20815;
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22
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Abstract
Germ line VHL tumor suppressor gene loss-of-function mutations cause von Hippel-Lindau disease, which is associated with an increased risk of central nervous system hemangioblastomas, clear cell renal carcinomas, and pheochromocytomas. Somatic VHL mutations are also common in sporadic clear cell renal carcinomas. The VHL gene product, pVHL, is part of a ubiquitin ligase complex that targets the alpha-subunits of the heterodimeric transcription factor hypoxia-inducible factor (HIF) for polyubiquitylation, and hence, proteasomal degradation, when oxygen is available. pVHL-defective clear cell renal carcinomas overproduce a variety of mRNAs that are under the control of HIF, including the mRNAs that encode vascular endothelial growth factor, platelet-derived growth factor B, and transforming growth factor alpha. In preclinical models, down-regulation of HIF-alpha, especially HIF-2alpha, is both necessary and sufficient for renal tumor suppression by pVHL. These observations are probably relevant to the demonstrated clinical activity of vascular endothelial growth factor antagonists in clear cell renal carcinoma and form a foundation for the testing of additional agents that inhibit HIF, or HIF-responsive gene products, in this disease.
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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, MA 02115, USA.
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23
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Abstract
Inactivation of the von Hippel-Lindau (VHL) tumor suppressor has been linked to a variety of tumors, including clear cell renal carcinoma, retinal and cerebellar hemangioblastoma, and pheochromocytoma. The best documented function of VHL protein (pVHL) relates to its ability to target the hypoxia-inducible transcription factor (HIF) for polyubiquitylation and proteasomal degradation. This chapter focuses on studies published over the past 2 years related to pVHL. These studies include those describing genetically engineered mice that were used to interrogate the relationship between pVHL and HIF in vivo and cell culture studies that underscore the importance of pVHL in epithelial differentiation and maintenance of the primary cilium. In addition, recent work suggests that pVHL regulates neuronal apoptosis in an HIF-independent manner, and this activity is linked to the risk of developing pheochromocytoma.
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Affiliation(s)
- William G Kaelin
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, USA
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24
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Abstract
Protein kinase C (PKC) comprises a superfamily of isoenzymes, many of which are activated by cofactors such as diacylglycerol and phosphatidylserine. In order to be capable of activation, PKC must first undergo a series of phosphorylations. In turn, activated PKC phosphorylates a wide variety of intracellular target proteins and has multiple functions in signal transduced cellular regulation. A role for PKC activation had been noted in several renal diseases, but two that have had most investigation are diabetic nephropathy and kidney cancer. In diabetic nephropathy, an elevation in diacylglycerol and/or other cofactor stimulants leads to an increase in activity of certain PKC isoforms, changes that are linked to the development of dysfunctional vasculature. The ability of isoform-specific PKC inhibitors to antagonize diabetes-induced vascular disease is a new avenue for treatment of this disorder. In the development and progressive invasiveness of kidney cancer, increased activity of several specific isoforms of PKC has been noted. It is thought that this may promote the kidney cancer's inherent resistance to apoptosis, in natural regression or after treatments, or it may promote the invasiveness of renal cancers via cellular differentiation pathways. In general, however, a more complete understanding of the functions of individual PKC isoforms in the kidney, and development or recognition of specific inhibitors or promoters of their activation, will be necessary to apply this knowledge for treatment of cellular dysregulation in renal disease.
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Affiliation(s)
- Jun Li
- Discipline of Molecular and Cellular Pathology, School of Medicine, University of Queensland, Brisbane, Queensland, Australia
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25
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Iturrioz X, Durgan J, Calleja V, Larijani B, Okuda H, Whelan R, Parker P. The von Hippel-Lindau tumour-suppressor protein interaction with protein kinase Cdelta. Biochem J 2006; 397:109-20. [PMID: 16669786 PMCID: PMC1479743 DOI: 10.1042/bj20060354] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The VHL (von Hippel-Lindau) tumour-suppressor protein forms a multi-protein complex [VCB (pVHL-elongin C-elongin B)-Cul-2 (Cullin-2)] with elongin C, elongin B, Cul-2 and Rbx1, acting as a ubiquitin-ligase (E3) and directing proteasome-dependent degradation of targeted proteins. The alpha-subunit of Hif1alpha (hypoxia-inducible factor 1alpha) is the principal substrate for the VCB-Cul-2 complex; however, other substrates such as aPKC (atypical protein kinase C) have been reported. In the present study, we show with FRET (fluorescence resonance energy transfer) analysis measured by FLIM (fluorescence lifetime imaging microscopy) that PKCdelta and pVHL (VHL protein) interact directly in cells. This occurs through the catalytic domain of PKCdelta (residues 432-508), which appears to interact with two regions of pVHL, residues 113-122 and 130-154. Despite this robust interaction, analysis of the PMA-induced proteasome-dependent degradation of PKCdelta in different RCC (renal cell carcinoma) lines (RCC4, UMRC2 and 786 O) shows that there is no correlation between the degradation of PKCdelta and the presence of active pVHL. Thus, in contrast with aPKC, PKCdelta is not a conventional substrate of the ubiquitin-ligase complex, VCB-Cul-2, and the observed interaction between these two proteins must underlie a distinct signalling output.
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Affiliation(s)
- Xavier Iturrioz
- *Protein Phosphorylation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Joanne Durgan
- *Protein Phosphorylation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Véronique Calleja
- ‡Cell Biophysics Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Banafshé Larijani
- ‡Cell Biophysics Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Heiwa Okuda
- §Department of Urology, Kochi Medical School, Kochi 783-8505, Japan
| | - Richard Whelan
- *Protein Phosphorylation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Peter J. Parker
- *Protein Phosphorylation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, U.K
- To whom correspondence should be addressed (email )
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26
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Abstract
Gliomas are the most common major subgroup of primary CNS tumours. Approximately 17,000 new cases are reported each year and, of these, 11,500 patients die. Glioblastoma multiforme (GBM) is highly proliferative and typically invades distal portions of the brain, thereby making complete surgical resection of these tumours nearly impossible. Moreover, GBMs are often resistant to current chemotherapy and radiation regimens. Therefore, there is a need for better therapeutic interventions. One class of proteins that is involved in the formation of malignant brain tumours is protein kinase C (PKC) and these kinases have not been thoroughly explored for their chemotherapeutic value in GBMs. The PKC isozyme, PKCeta (PKC-eta) increases cell proliferation and resistance to radiation of GBM cell lines. These properties make PKCeta an attractive target for chemotherapeutic intervention in the management of GBMs.
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Affiliation(s)
- Patrick M Martin
- Department of Pathology, University of Virginia, Charlottesville, VA, USA.
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27
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Xue Y, Bi F, Zhang X, Zhang S, Pan Y, Liu N, Shi Y, Yao X, Zheng Y, Fan D. Role of Rac1 and Cdc42 in hypoxia induced p53 and von Hippel-Lindau suppression and HIF1alpha activation. Int J Cancer 2006; 118:2965-72. [PMID: 16395716 DOI: 10.1002/ijc.21763] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low oxygen tension can influence tumor progression by enhancing angiogenesis, a process that may involve Rho GTPases whose activities have been implicated in tumorigenesis and metastasis. In the present study, we show that hypoxia can increase the mRNA levels and intracellular activities of Rac1 and Cdc42 in a time-dependent manner. The hypoxia-stimulated activities of Rac1 and Cdc42 could be blocked by the phosphatidylinositol 3'-kinase (PI3K) inhibitor LY294002 and the protein tyrosine kinase (PTK) inhibitor genistein but were not affected by the p38MAPK inhibitor SB203580 or the MEK-1 inhibitor PD98059, suggesting that the hypoxia-mediated signals were through PI3K and PTK. Correlating with the increased activities of Rac1 and Cdc42, the expression of the pro-angiogenesis factors HIF-1alpha and vascular endothelial growth factor (VEGF) was upregulated by hypoxia, whereas the expression of the tumor suppressors von Hippel-Lindau and p53 was down-regulated. Dominant negative N17Rac1 and N17Cdc42 could upregulate the expression of p53 and pVHL but downregulate that of HIF-1alpha and VEGF under hypoxia. Furthermore, the preconditioned medium from N17Rac1 or N17Cdc42-expressing gastric cancer cells was able to inhibit the proliferation of HUVECs. Our results indicate that PI3K and PTK-mediated activations of Rac1 and Cdc42 are involved in the hypoxia-induced production of angiogenesis-promoting factors and tumor suppressors, and suggest that the Rho family GTPases Rac1 and Cdc42 may contribute to the hypoxia-mediated angiogenesis.
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Affiliation(s)
- Yan Xue
- The State Key Laboratory of Cancer Biology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
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28
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Tang N, Mack F, Haase VH, Simon MC, Johnson RS. pVHL function is essential for endothelial extracellular matrix deposition. Mol Cell Biol 2006; 26:2519-30. [PMID: 16537898 PMCID: PMC1430327 DOI: 10.1128/mcb.26.7.2519-2530.2006] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The tumor suppressor von Hippel-Lindau protein (pVHL) is critical for cellular molecular oxygen sensing, acting to target degradation of the hypoxia-inducible factor alpha transcription factor subunits under normoxic conditions. We have found that independent of its function in regulating hypoxic response, the VHL gene plays a critical role in embryonic endothelium development through regulation of vascular extracellular matrix assembly. We created mice lacking the VHL gene in endothelial cells; these conditional null mice died at the same stage as homozygous VHL-null mice, with similar vascular developmental defects. These included defective vasculogenesis in the placental labyrinth, a collapsed endocardium, and impaired vessel network patterning. The defects in embryonic vascularization were correlated with a diminished vascular fibronectin deposition in vivo and defective endothelial extracellular fibronectin assembly in vitro. We found that the impaired migration and adhesion of VHL-null endothelial cells can be partially rescued by the addition of back exogenous fibronectin, which indicates that pVHL regulation of fibronectin deposition plays an important functional role in vascular patterning and maintenance of vascular integrity.
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Affiliation(s)
- Nan Tang
- Molecular Biology Section, MC-0377, Division of Biological Sciences, University of California--San Diego, La Jolla, California 92093-0377, USA
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29
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Abstract
Over the past decade major advances have been made in our understanding of the molecular machinery that mammalian cells use to sense and to adapt to a low-oxygen environment. A critical mediator of cellular adaptation to hypoxia is hypoxia-inducible factor (HIF), a basic helix-loop-helix transcription factor that consists of an oxygen-sensitive alpha-subunit, HIF-alpha and a constitutively expressed beta-subunit, HIF-beta. Under conditions of normal oxygen tension, the HIF-alpha subunit is hydroxylated by specific prolyl-hydroxylases and targeted for rapid proteasomal degradation by the von Hippel-Lindau (VHL) tumor suppressor, which is the substrate recognition component of an E3-ubiquitin ligase. In a hypoxic environment or in the absence of functional VHL tumor suppressor protein irrespective of oxygen concentration, HIF-alpha is not degraded and translocates to the nucleus, where it dimerizes with HIF-beta to form transcriptionally active HIF. As a transcription factor, HIF is involved in the regulation of many biological processes that facilitate both oxygen delivery and adaptation to oxygen deprivation by regulating genes that are involved in glucose uptake and energy metabolism, angiogenesis, erythropoiesis, cell proliferation and apoptosis, cell-cell and cell-matrix interactions, and barrier function. This review summarizes some of the most recent advances in the VHL/HIF field and discusses their relevance for pathogenesis and treatment of acute ischemic renal failure, renal fibrosis, and renal cancer.
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Affiliation(s)
- V H Haase
- Renal Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104-6144, USA.
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30
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Tsuchihashi SI, Ke B, Kaldas F, Flynn E, Busuttil RW, Briscoe DM, Kupiec-Weglinski JW. Vascular endothelial growth factor antagonist modulates leukocyte trafficking and protects mouse livers against ischemia/reperfusion injury. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 168:695-705. [PMID: 16436682 PMCID: PMC1780159 DOI: 10.2353/ajpath.2006.050759] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although hypoxia stimulates the expression of vascular endothelial growth factor (VEGF), little is known of the role or mechanism by which VEGF functions after ischemia and reperfusion (I/R) injury. In this report, we first evaluated the expression of VEGF in a mouse model of liver warm ischemia. We found that the expression of VEGF increased after ischemia but peaked between 2 and 6 hours after reperfusion. Mice were treated with a neutralizing anti-mouse VEGF antiserum (anti-VEGF) or control serum daily from day -1 (1 day before the initiation of ischemia). Treatment with anti-VEGF significantly reduced serum glutaminic pyruvic transaminase levels and reduced histological evidence of hepatocellular damage compared with controls. Anti-VEGF also markedly decreased T-cell, macrophage, and neutrophil accumulation within livers and reduced the frequency of intrahepatic apoptotic terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells. Moreover, there was a reduction in the expression of pro-inflammatory cytokines (tumor necrosis factor-alpha and interferon-gamma), chemokines (interferon-inducible protein-10 and monocyte chemoattractant protein-1) and adhesion molecules (E-selectin) in parallel with enhanced expression of anti-apoptotic genes (Bcl-2/Bcl-xl and heme oxygenase-1) in anti-VEGF-treated animals. In conclusion, hypoxia-inducible VEGF expression by hepatocytes modulates leukocyte trafficking and leukocyte-induced injury in a mouse liver model of warm I/R injury, demonstrating the importance of endogenous VEGF production in the pathophysiology of hepatic I/R injury.
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Nakamura E, Abreu-e-Lima P, Awakura Y, Inoue T, Kamoto T, Ogawa O, Kotani H, Manabe T, Zhang GJ, Kondo K, Nosé V, Kaelin WG. Clusterin is a secreted marker for a hypoxia-inducible factor-independent function of the von Hippel-Lindau tumor suppressor protein. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 168:574-84. [PMID: 16436671 PMCID: PMC1606480 DOI: 10.2353/ajpath.2006.050867] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/30/2005] [Indexed: 12/23/2022]
Abstract
Germline mutations in the von Hippel-Lindau (VHL) tumor suppressor gene predispose people to renal cancer, hemangioblastomas, and pheochromocytomas in an allele-specific manner. The best documented function of the VHL gene product (pVHL) relates to its ability to polyubiquitinate, and hence target for destruction, the alpha subunits of the heterodimeric transcription factor hypoxia-inducible factor (HIF). pVHL mutants linked to familial pheochromocyctoma (type 2C VHL disease), in contrast to classical VHL disease, appear to be normal with respect to HIF regulation. Using a simple method for identifying proteins that are differentially secreted by isogenic cell line pairs, we confirmed that the HIF targets IGBP3 and PAI-1 are overproduced by pVHL-defective renal carcinoma cells. In addition, cells lacking wild-type pVHL, including cells producing type 2C pVHL mutants, were defective with respect to expression and secretion of clusterin, which does not behave like a HIF target. Decreased clusterin secretion by pVHL-defective tumors was confirmed in vivo by immunohistochemistry. Therefore, clusterin is a secreted marker for a HIF-independent pVHL function that might be especially important in pheochromocytoma development.
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Affiliation(s)
- Eijiro Nakamura
- Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney St., Boston, MA 02115, USA
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Dorai T, Sawczuk IS, Pastorek J, Wiernik PH, Dutcher JP. The role of carbonic anhydrase IX overexpression in kidney cancer. Eur J Cancer 2006; 41:2935-47. [PMID: 16310354 DOI: 10.1016/j.ejca.2005.09.011] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 08/23/2005] [Accepted: 09/02/2005] [Indexed: 01/03/2023]
Abstract
Carbonic anhydrase IX (CA IX) is a membrane isoenzyme, the overexpression of which is associated with clear cell carcinoma of the kidney. Its overexpression is restricted mainly to cancer, as it is absent in corresponding normal tissues making it a potential cancer biomarker. Several recent studies have shown that CA IX, apart from its classical enzyme activity of reversibly hydrating carbon dioxide extracellularly to facilitate the net extrusion of protons from inside to outside the cell, it can also be a key player in the modulation of cell adhesion processes and participate in the regulation of cell proliferation in response to hypoxic environment to ultimately contribute to tumour progression. Here, we have shown that the sole tyrosine moiety of CA IX present in its intracellular domain can be phosphorylated in an epidermal growth factor dependent manner, suggesting that it can feed into the growth factor receptor dependent signalling pathways. Our studies suggest that the tyrosine phosphorylated CA IX can interact with the regulatory subunit of PI-3-Kinase, contributing to Akt activation. These studies have revealed a positive feed back loop that can form the basis of a vicious cycle that could contribute to the progression of clear cell renal carcinoma and poor prognosis. These studies show that CA IX signalling may be a part of both the hypoxia driven and hypoxia independent pathways that occur in the cancer cell. Finally, our studies emphasize the need for a more refined strategy using signal transduction therapeutics to inhibit the cell surface carbonic anhydrases for the management of this malignancy.
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Affiliation(s)
- Thambi Dorai
- Comprehensive Cancer Center, Our Lady of Mercy Medical Center, New York Medical College, Bronx, NY 10466-2697, USA.
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33
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Nakamura E, Kaelin WG. Recent insights into the molecular pathogenesis of pheochromocytoma and paraganglioma. Endocr Pathol 2006; 17:97-106. [PMID: 17159241 DOI: 10.1385/ep:17:2:97] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 02/07/2023]
Abstract
Pheochromocytomas and paragangliomas are rare tumors derived from chromaffin cells. These tumors can arise in the context of hereditary cancer syndromes such as von Hippel- Lindau disease, multiple endocrine neoplasia type 2, and neurofibromatosis 1. Recent studies indicate that germ line mutations of genes encoding specific succinate dehydrogenase (SDH) subunits also predispose individuals to pheochromocytomas and paragangliomas. This review focuses on the genetics of these tumors and suggests a possible link between familial pheochromocytomas/paraganglioma genes and control of neuronal apoptosis during embryological development.
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Affiliation(s)
- Eijiro Nakamura
- Department of Urology, Graduate School of Medicine, Kyoto University
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34
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Lackner C, Dlaska D, Fuchsbichler A, Stumptner C, Gogg-Kamerer M, Zatloukal K, Denk H. p62 protein is expressed in pancreatic beta cells. J Pathol 2005; 206:402-8. [PMID: 15926199 DOI: 10.1002/path.1786] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
p62 is a cellular protein that plays an adapter role in signal transduction pathways involved in such diverse biological functions as proliferation, differentiation, reaction to oxidative stress and immune response. Furthermore, p62 has recently been detected as a component of intracytoplasmic protein aggregates (inclusion bodies), which are hallmarks of a variety of chronic degenerative disorders, such as Parkinson's disease and Alzheimer's disease, but also of steatohepatitis. Here we report that p62 and insulin are co-expressed in a diffuse fashion in beta cells in normal human pancreas as well as in primary chronic pancreatitis and in normal pancreas from mouse and swine. In contrast, p62 protein is absent from, or only focally and very weakly expressed in, insulinomas, glucagonomas or non-functioning pancreatic neuroendocrine tumours or carcinomas that express insulin or other pancreatic as well as extrapancreatic hormones. Although the biological function of p62 in beta cells is unknown, the co-expression of p62 and insulin in non-neoplastic beta cells suggests that, in the beta cell, p62 may play a role in specific insulin-related signalling. Since p62 may also be involved in pro-apototic signal transduction, the loss of p62 expression in neuroendocrine neoplasms of the pancreas may render the tumour cells less sensitive to pro-apototic signals. Further research is necessary to elucidate the role of p62 in beta cell-specific signal transduction.
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Affiliation(s)
- Carolin Lackner
- Institute of Pathology, Medical University of Graz, Austria.
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35
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Kaelin WG. The von Hippel-Lindau protein, HIF hydroxylation, and oxygen sensing. Biochem Biophys Res Commun 2005; 338:627-38. [PMID: 16153592 DOI: 10.1016/j.bbrc.2005.08.165] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 08/23/2005] [Indexed: 12/31/2022]
Abstract
The heterodimeric transcription factor HIF (hypoxia-inducible factor), consisting of a labile alpha-subunit and a stable beta-subunit, is a master regulator of genes involved in acute or chronic adaptation to low oxygen. Studies performed over the past 5 years revealed that HIFalpha-subunits are enzymatically hydroxylated in an oxygen-dependent manner. Hydroxylation of either of two conserved prolyl residues targets HIFalpha for destruction by a ubiquitin ligase containing the von Hippel-Lindau tumor suppressor protein whereas hydroxylation on a C-terminal asparagine affects HIF transactivation function. Pharmacological manipulation of HIF activity might be beneficial in diseases characterized by abnormal tissue oxygenation including myocardial infarction, cerebrovascular disease, and cancer.
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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, MA 02115, USA.
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36
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Lee S, Nakamura E, Yang H, Wei W, Linggi MS, Sajan MP, Farese RV, Freeman RS, Carter BD, Kaelin WG, Schlisio S. Neuronal apoptosis linked to EglN3 prolyl hydroxylase and familial pheochromocytoma genes: developmental culling and cancer. Cancer Cell 2005; 8:155-67. [PMID: 16098468 DOI: 10.1016/j.ccr.2005.06.015] [Citation(s) in RCA: 400] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Revised: 04/29/2005] [Accepted: 06/07/2005] [Indexed: 01/11/2023]
Abstract
Germline NF1, c-RET, SDH, and VHL mutations cause familial pheochromocytoma. Pheochromocytomas derive from sympathetic neuronal precursor cells. Many of these cells undergo c-Jun-dependent apoptosis during normal development as NGF becomes limiting. NF1 encodes a GAP for the NGF receptor TrkA, and NF1 mutations promote survival after NGF withdrawal. We found that pheochromocytoma-associated c-RET and VHL mutations lead to increased JunB, which blunts neuronal apoptosis after NGF withdrawal. We also found that the prolyl hydroxylase EglN3 acts downstream of c-Jun and is specifically required among the three EglN family members for apoptosis in this setting. Moreover, EglN3 proapoptotic activity requires SDH activity because EglN3 is feedback inhibited by succinate. These studies suggest that failure of developmental apoptosis plays a role in pheochromocytoma pathogenesis.
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Affiliation(s)
- Sungwoo Lee
- Department of Medical Oncology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Haase VH. The VHL tumor suppressor in development and disease: functional studies in mice by conditional gene targeting. Semin Cell Dev Biol 2005; 16:564-74. [PMID: 15908240 PMCID: PMC3787877 DOI: 10.1016/j.semcdb.2005.03.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The von Hippel-Lindau tumor suppressor pVHL plays a critical role in the pathogenesis of familial and sporadic clear cell carcinomas of the kidney and hemangioblastomas of the retina and central nervous system. pVHL targets the oxygen sensitive alpha subunit of hypoxia-inducible factor (HIF) for proteasomal degradation, thus providing a direct link between tumorigenesis and molecular pathways critical for cellular adaptation to hypoxia. Cell type specific gene targeting of VHL in mice has demonstrated that proper pVHL mediated HIF proteolysis is fundamentally important for survival, proliferation and differentiation of many cell types and furthermore, that inactivation of pVHL may, unexpectedly, inhibit tumor growth under certain conditions. Mouse knock out studies have provided novel mechanistic insights into VHL associated tumorigenesis and established a central role for HIF in the development of the VHL phenotype.
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Affiliation(s)
- Volker H Haase
- Department of Medicine, University of Pennsylvania School of Medicine, 700 CRB, 415 Curie Boulevard, Philadelphia, PA 19104-6144, USA.
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38
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Xie K, Wei D, Shi Q, Huang S. Constitutive and inducible expression and regulation of vascular endothelial growth factor. Cytokine Growth Factor Rev 2005; 15:297-324. [PMID: 15450248 DOI: 10.1016/j.cytogfr.2004.04.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Vascular endothelial growth factor (VEGF), which was originally discovered as vascular permeability factor, is critical to human cancer angiogenesis through its potent functions as a stimulator of endothelial cell survival, mitogenesis, migration, differentiation and self-assembly, as well as vascular permeability, immunosuppression and mobilization of endothelial progenitor cells from the bone marrow into the peripheral circulation. Genetic alterations and a chaotic tumor microenvironment, such as hypoxia, acidosis, free radicals, and cytokines, are clearly attributed to numerous abnormalities in the expression and signaling of VEGF and its receptors. These perturbations confer a tremendous survival and growth advantage to vascular endothelial cells as manifested by exuberant tumor angiogenesis and a consequent malignant phenotype. Understanding the regulatory mechanisms of both inducible and constitutive VEGF expression will be crucial in designing effective therapeutic strategies targeting VEGF to control tumor growth and metastasis. In this review, molecular regulation of VEGF expression in tumor cells is discussed.
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Affiliation(s)
- Keping Xie
- Department of Gastrointestinal Medical Oncology, Unit 426, MD Anderson Cancer Center, The University of Texas, Houston, TX 77030, USA
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39
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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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40
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de Waal RMW, Leenders WPJ. Sprouting angiogenesis versus co-option in tumor angiogenesis. EXS 2005:65-76. [PMID: 15617471 DOI: 10.1007/3-7643-7311-3_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Robert M W de Waal
- Department of Pathology 437, University Medical Centre Nijmegen, PO. Box 9101, 6500 HB Nijmegen, The Netherlands.
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41
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Turcotte S, Desrosiers RR, Brand G, Béliveau R. von Hippel-Lindau tumor suppressor protein stimulation by thrombin involves RhoA activation. Int J Cancer 2004; 112:777-86. [PMID: 15386385 DOI: 10.1002/ijc.20468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is associated with the development of vascular tumors including renal cell carcinoma. Aside from the role played by the VHL protein (pVHL) in negative regulation of hypoxia-inducible factor, 41F-1alpha, pVHL also takes part in cytoskeletal organization. Thrombin is a serine protease involved in angiogenesis and in cancer progression and its action is mediated by the protease-activated receptors (PARs). In several cell types, thrombin induces reorganization of the cytoskeleton along with RhoA activation. Thus, we conducted an investigation on the capacity of thrombin to regulate pVHL expression. Our results demonstrated that VHL mRNA and protein levels were increased by thrombin in cultured renal cancer cells. Cytoplasmic pVHL was redistributed to perinuclear regions and membrane fractions following thrombin treatments. Stimulation of Caki-1 cells with PAR1, PAR2 and PAR4 agonist peptides demonstrated that PAR1 was the receptor involved in thrombin-induced pVHL expression. Western blot analysis confirmed that these cells express PAR1 and that its expression was increased by thrombin. PAR1 activation by both thrombin and an agonist peptide stimulated renal cancer cell invasion through Matrigel. Interestingly, the upregulation of pVHL was dependent on RhoA because C3 exotoxin abolished pVHL induction. However, the pharmacological Rho kinase inhibitor, Y27632, did not influence pVHL expression in the presence of thrombin, suggesting that other RhoA effectors were involved in the process. Together, these results demonstrate that thrombin induces both pVHL expression via PAR1/RhoA activation as well as the stimulation of renal cancer cell invasion suggesting a role for thrombin in tumor invasion.
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Affiliation(s)
- Sandra Turcotte
- Laboratoire de Médecine Moléculaire, Hôpital Sainte-Justine, Université du Québec à Montréal, Montréal, Québec
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42
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Rini BI, Weinberg V, Shaw V, Scott J, Bok R, Park JW, Small EJ. Time to disease progression to evaluate a novel protein kinase C inhibitor, UCN-01, in renal cell carcinoma. Cancer 2004; 101:90-5. [PMID: 15221993 DOI: 10.1002/cncr.20313] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Renal cell carcinoma (RCC) is characterized by von Hippel-Lindau gene inactivation and vascular endothelial growth factor (VEGF) overproduction. The mechanism of VEGF overproduction may involve protein kinase C (PKC) delta and zeta isoforms. UCN-01 (7-hydroxystaurosporine) is a selective inhibitor of PKC. Given the historically low objective response rate in RCC, time to disease progression (TTP) as an alternative endpoint was employed to evaluate the antitumor activity of UCN-01 in RCC. METHODS Patients with progressive, metastatic RCC received UCN-01 intravenously on Day 1 of each 21-day cycle. The initial dose was 90 mg/m(2) and all subsequent doses were 45 mg/m(2) unless modified for toxicity. TTP was the primary endpoint, defined as the period from the first day of treatment until disease progression. Detection of circulating EpCAM-positive renal carcinoma cells was undertaken for predictive or prognostic potential. RESULTS Twenty-one patients were enrolled in this Phase II study. Accrual was halted after failure to reach a predetermined efficacy requirement with 7 patients remaining disease progression free after 4 months (6 cycles). The median TTP for all patients was 2.67 months (range, 0.4-7.6 months). There were no objective responses. Therapy was generally well tolerated. Thirteen patients had < 0.6 EpCAM-positive cells/mL (considered negative) at all time points measured. Two patients had detectable EpCAM-positive cells at a single time point with other measurements being negative. CONCLUSIONS TTP is a novel endpoint for the evaluation of agents in RCC. UCN-01 did not demonstrate significant antitumor activity. No evidence for significant circulating EpCAM-positive cells was found in this study cohort.
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Affiliation(s)
- Brian I Rini
- UCSF Comprehensive Cancer Center, The University of California-San Francisco, 1600 Divisadero, Rm. A717, San Francisco, CA 94115, USA.
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43
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Jackson DN, Foster DA. The enigmatic protein kinase Cdelta: complex roles in cell proliferation and survival. FASEB J 2004; 18:627-36. [PMID: 15054085 DOI: 10.1096/fj.03-0979rev] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein kinase Cdelta (PKCdelta) has been implicated both as a tumor suppressor and a positive regulator of cell cycle progression. PKCdelta has also been reported to positively and negatively regulate apoptotic programs. This has led to conflicting hypotheses on the role of PKCdelta in the control of cell proliferation and survival. Surprisingly, PKCdelta mice develop normally and are fertile, indicating that PKCdelta is not critical for normal cell proliferation during development. However, PKCdelta may play important roles in neoplastic cell proliferation. In this review, we have summarized the apparent multifunctional properties of this enigmatic protein with regard to its role in the regulation of cell cycle progression and cell survival. It is proposed that PKCdelta has both tumor suppressor and proliferation capabilities that can be recruited as a backup kinase for both gatekeeper tumor suppression and as an activator of the Ras/Raf/MEK/MAP kinase signaling pathway in cell proliferation.
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Affiliation(s)
- Desmond N Jackson
- Department of Biological Sciences, Hunter College of The City University of New York, New York, NY 10021, USA
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44
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Kim M, Yan Y, Lee K, Sgagias M, Cowan KH. Ectopic expression of von Hippel–Lindau tumor suppressor induces apoptosis in 786-O renal cell carcinoma cells and regresses tumor growth of 786-O cells in nude mouse. Biochem Biophys Res Commun 2004; 320:945-50. [PMID: 15240140 DOI: 10.1016/j.bbrc.2004.06.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Indexed: 10/26/2022]
Abstract
The von Hippel-Lindau (VHL) is a known tumor suppressor that binds to alpha-subunits of hypoxia-inducible factors and induces ubiquitin-mediated degradation of the protein in an oxygen-dependent manner. VHL is also involved in the regulation of tumor angiogenesis, glycolysis, cell cycle regulation, and apoptosis. In the present study, we showed that ectopic expression of VHL induces apoptosis in renal cell carcinoma 786-O cells which contain only the mutant VHL, evidenced by TUNEL assay and DAPI staining. Furthermore, biochemical studies indicated that expression of VHL in 786-O cells results in both PARP and CPP32 cleavage, suggesting that VHL-induced apoptosis in 786-O cells is caspase dependent. Moreover, we also observed that apoptosis induced by ectopic VHL expression was associated with up-regulation of p27 as well as Bax, implicating the roles of these two proteins in VHL-induced apoptosis. The up-regulation of p27 and Bax by VHL was specific since we did not detect any changes in the level of other apoptotic factors including Fas and Bcl2 by the expression of VHL. We next examined the effect of VHL expression on the tumor growth of 786-O renal cell carcinoma cells in nude mouse. The results showed that injection of Ad.VHL adenovirus regresses the tumor growth of 786-O cells in nude mouse. The analysis by TUNEL assay as well as DAPI staining of 786-O tumors injected with Ad.VHL showed clear evidence of apoptosis. These results suggest that ectopic VHL expression induces apoptotic response in 786-O VHL mutant cells both in vitro and in vivo.
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Affiliation(s)
- Min Kim
- Children's National Medical Center, Washington, DC 20010, USA.
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45
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Wang YQ, Luk JM, Ikeda K, Man K, Chu AC, Kaneda K, Fan ST. Regulatory role of vHL/HIF-1alpha in hypoxia-induced VEGF production in hepatic stellate cells. Biochem Biophys Res Commun 2004; 317:358-62. [PMID: 15063765 DOI: 10.1016/j.bbrc.2004.03.050] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Indexed: 01/11/2023]
Abstract
Activated hepatic stellate cells (HSCs) produce cyclooxygenase-2 (COX-2) protein to induce vascular endothelial growth factor (VEGF) production that participates in angiogenesis in injured liver. To reveal the unknown regulatory mechanism, we used hypoxic atmosphere mimicking injured-tissue microenvironment to induce VEGF expression in a rat hepatic stellate cell line (T6-HSCs). The present study showed that hypoxia up-regulated the protein levels of COX-2 and hypoxia-inducible factor-1-alpha (HIF-1alpha), but rapidly effected degradation of von Hippel-Lindau (vHL) protein. As a result, expression of VEGF in HSCs was markedly elevated; and pretreatment with COX-2 inhibitors (nimesulide or indomethacin) could significantly ameliorate the angiogenic event. Collectively, hypoxic HSCs increased accumulation of HIF-1alpha protein and induced VEGF expression in a time-dependent manner. Inhibition of COX-2 activities would prevent vHL protein from degradation and suppress HIF-1alpha up-regulation. Thus, vHL/HIF-1alpha has a regulatory role in COX-2-mediated VEGF production in hypoxic stellate cells in injured liver.
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Affiliation(s)
- Yang Q Wang
- Centre for the Study of Liver Disease and Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong
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46
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Datta K, Li J, Bhattacharya R, Gasparian L, Wang E, Mukhopadhyay D. Protein kinase C zeta transactivates hypoxia-inducible factor alpha by promoting its association with p300 in renal cancer. Cancer Res 2004; 64:456-62. [PMID: 14744756 DOI: 10.1158/0008-5472.can-03-2706] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hydroxylation at an asparagine residue at the COOH-terminal activation domain of hypoxia-inducible factor (HIF)-1/2 alphas is essential for its inactivation under normoxic condition. To date, the mechanism by which HIF-alpha avoids the inhibitory effect of asparagine hydroxylase in renal cell carcinoma (RCC) in normoxia is undefined. We have shown herein that protein kinase C (PKC) zeta has an important role in HIF-alpha activation in RCC. By using dominant negative mutant and small interference RNA approaches, we have demonstrated that the association between HIF-alpha and p300 is modulated by PKCzeta. Moreover, a novel signaling pathway involving phosphatidylinositol 3'-kinase and PKCzeta has been shown to be responsible for the activation of HIF-alpha by inhibiting the mRNA expression of FIH-1 (factor inhibiting HIF-1) in RCC and thereby promoting the transcription of hypoxia-inducible genes such as vascular permeability factor/vascular endothelial growth factor.
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Affiliation(s)
- Kaustubh Datta
- Departmens of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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47
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Bamias A, Dimopoulos MA. Angiogenesis in human cancer: implications in cancer therapy. Eur J Intern Med 2003; 14:459-469. [PMID: 14962697 DOI: 10.1016/j.ejim.2003.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Accepted: 10/14/2003] [Indexed: 12/13/2022]
Abstract
Angiogenesis represents an essential step in tumor proliferation, expansion, and metastasis. Tumor cells may express both proangiogenic and/or antiangiogenic factors. Under normal circumstances, angiogenesis is controlled through the equilibrium of these factors. This balance is disrupted in malignancy, resulting in promotion of angiogenesis. Among angiogenic molecules, VEGF appears to have a central role in the angiogenic process: it is the target of many proangiogenic factors, but it also regulates molecules that are implicated in endothelial proliferation. It has been suggested that VEGF may be a proximate angiogenic factor through which others act. The degree of angiogenesis and the expression of angiogenic factors have been associated with prognosis in several human neoplasms. In addition, angiogenesis offers a theoretically selective target for anticancer therapy, since it is only required for wound healing, endometrial proliferation, and pregnancy in healthy individuals. Antiangiogenic cancer treatment is still largely experimental and its clinical potential is currently being studied in clinical trials. Thalidomide, a drug with antiangiogenic properties, has shown significant efficacy in patients with relapsed or refractory multiple myeloma. In addition, an anti-VEGF monoclonal antibody prolonged survival in patients with advanced colorectal and renal cell carcinoma. Although these results are encouraging, selection of patients is essential in order to target populations most likely to benefit from antiangiogenic therapy.
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Affiliation(s)
- Aristotle Bamias
- Department of Clinical Therapeutics, School of Medicine, University of Athens, Medical School, 31 Komninon Street, Haidari, 124 62 Athens, Greece
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Madhusudan S, Protheroe A, Propper D, Han C, Corrie P, Earl H, Hancock B, Vasey P, Turner A, Balkwill F, Hoare S, Harris AL. A multicentre phase II trial of bryostatin-1 in patients with advanced renal cancer. Br J Cancer 2003; 89:1418-22. [PMID: 14562010 PMCID: PMC2394342 DOI: 10.1038/sj.bjc.6601321] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Protein kinase C (PKC) has a critical role in several signal transduction pathways, and is involved in renal cancer pathogenesis. Bryostatin-1 modulates PKC activity and has antitumour effects in preclinical studies. We conducted a multicentre phase II clinical trial in patients with advanced renal cancer to determine the response rate, immunomodulatory activity and toxicity of bryostatin-1 given as a continuous 24 h infusion weekly for 3 out of 4 weeks at a dose of 25 μg m−2. In all, 16 patients were recruited (11 males and five females). The median age was 59 years (range 44–68). Patients had been treated previously with nephrectomy (8) and/or interferon therapy (9) and/or hormone therapy (4) and/or radiotherapy (6). Eight, five and three patients had performance statuses of 0, 1 and 2, respectively. A total of 181 infusions were administered with a median of 12 infusions per patient (range 1–29). Disease response was evaluable in 13 patients. Three patients achieved stable disease lasting for 10.5, 8 and 5.5 months, respectively. No complete responses or partial responses were seen. Myalgia, fatigue, nausea, headache, vomiting, anorexia, anaemia and lymphopenia were the commonly reported side effects. Assessment of biological activity of bryostatin-1 was carried out using the whole–blood cytokine release assay in six patients, two of whom had a rise in IL-6 levels 24 h after initiating bryostatin-1 therapy compared to pretreatment values. However, the IL-6 level was found to be significantly lower at day 28 compared to the pretreatment level in all six patients analysed.
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Affiliation(s)
- S Madhusudan
- Cancer Research UK Medical Oncology Unit, Churchill Hospital, Oxford, UK
| | - A Protheroe
- Cancer Research UK Medical Oncology Unit, Churchill Hospital, Oxford, UK
| | - D Propper
- Cancer Research UK Medical Oncology Unit, Churchill Hospital, Oxford, UK
| | - C Han
- Cancer Research UK Medical Oncology Unit, Churchill Hospital, Oxford, UK
| | - P Corrie
- Department of Oncology, Addenbrooke's Hospital, Cambridge UK
| | - H Earl
- Department of Oncology, Addenbrooke's Hospital, Cambridge UK
| | - B Hancock
- Department of Clinical Oncology, Weston Park Hospital, Sheffield, UK
| | - P Vasey
- Beatson Oncology Centre, Western Infirmary, Glasgow, UK
| | - A Turner
- Drug Development Office, Cancer Research UK, 61 Lincoln's Inn Fields, London, UK
| | - F Balkwill
- Cancer Research UK Translational Oncology Laboratory, Barts & The London, Queen Mary's Medical School, Charterhouse Square, London UK
| | - S Hoare
- Cancer Research UK Translational Oncology Laboratory, Barts & The London, Queen Mary's Medical School, Charterhouse Square, London UK
| | - A L Harris
- Cancer Research UK Medical Oncology Unit, Churchill Hospital, Oxford, UK
- Cancer Research UK Medical Oncology Unit, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK. E-mail:
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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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Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches. Ann Surg 2003. [PMID: 12832961 DOI: 10.1097/00000658-200307000-00003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers. SUMMARY BACKGROUND DATA Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers. METHODS A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words. RESULTS Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers. CONCLUSIONS There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.
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