1
|
Rahimi N, White MR, Amraei R, Lotfollahzadeh S, Xia C, Michalak M, Costello CE, Mühlberger E. Calreticulin Regulates SARS-CoV-2 Spike Protein Turnover and Modulates SARS-CoV-2 Infectivity. Cells 2023; 12:2694. [PMID: 38067122 PMCID: PMC10705507 DOI: 10.3390/cells12232694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/14/2023] [Accepted: 11/18/2023] [Indexed: 12/18/2023] Open
Abstract
Cardiovascular complications are major clinical hallmarks of acute and post-acute coronavirus disease 2019 (COVID-19). However, the mechanistic details of SARS-CoV-2 infectivity of endothelial cells remain largely unknown. Here, we demonstrate that the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) protein shares a similarity with the proline-rich binding ena/VASP homology (EVH1) domain and identified the endoplasmic reticulum (ER) resident calreticulin (CALR) as an S-RBD interacting protein. Our biochemical analysis showed that CALR, via its proline-rich (P) domain, interacts with S-RBD and modulates proteostasis of the S protein. Treatment of cells with the proteasomal inhibitor bortezomib increased the expression of the S protein independent of CALR, whereas the lysosomal/autophagy inhibitor bafilomycin 1A, which interferes with the acidification of lysosome, selectively augmented the S protein levels in a CALR-dependent manner. More importantly, the shRNA-mediated knockdown of CALR increased SARS-CoV-2 infection and impaired calcium homeostasis of human endothelial cells. This study provides new insight into the infectivity of SARS-CoV-2, calcium hemostasis, and the role of CALR in the ER-lysosome-dependent proteolysis of the spike protein, which could be associated with cardiovascular complications in COVID-19 patients.
Collapse
Affiliation(s)
- Nader Rahimi
- Department of Pathology, School of Medicine, Boston University, Boston, MA 02118, USA;
| | - Mitchell R. White
- Department of Microbiology, School of Medicine, Boston University, Boston, MA 02118, USA; (M.R.W.); (E.M.)
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, Boston, MA 02118, USA
| | - Razie Amraei
- Department of Pathology, School of Medicine, Boston University, Boston, MA 02118, USA;
| | - Saran Lotfollahzadeh
- Renal Section, Department of Medicine, Medical Center, Boston University, Boston, MA 02118, USA;
| | - Chaoshuang Xia
- Center for Biomedical Mass Spectrometry, School of Medicine, Boston University, Boston, MA 02118, USA; (C.X.); (C.E.C.)
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
| | - Catherine E. Costello
- Center for Biomedical Mass Spectrometry, School of Medicine, Boston University, Boston, MA 02118, USA; (C.X.); (C.E.C.)
| | - Elke Mühlberger
- Department of Microbiology, School of Medicine, Boston University, Boston, MA 02118, USA; (M.R.W.); (E.M.)
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, Boston, MA 02118, USA
| |
Collapse
|
2
|
Saikia Q, Reeve H, Alzahrani A, Critchley WR, Zeqiraj E, Divan A, Harrison MA, Ponnambalam S. VEGFR endocytosis: Implications for angiogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 194:109-139. [PMID: 36631189 DOI: 10.1016/bs.pmbts.2022.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The binding of vascular endothelial growth factor (VEGF) superfamily to VEGF receptor tyrosine kinases (VEGFRs) and co-receptors regulates vasculogenesis, angiogenesis and lymphangiogenesis. A recurring theme is that dysfunction in VEGF signaling promotes pathological angiogenesis, an important feature of cancer and pro-inflammatory disease states. Endocytosis of basal (resting) or activated VEGFRs facilitates signal attenuation and endothelial quiescence. However, increasing evidence suggest that activated VEGFRs can continue to signal from intracellular compartments such as endosomes. In this chapter, we focus on the evolving link between VEGFR endocytosis, signaling and turnover and the implications for angiogenesis. There is much interest in how such understanding of VEGFR dynamics can be harnessed therapeutically for a wide range of human disease states.
Collapse
Affiliation(s)
- Queen Saikia
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Hannah Reeve
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Areej Alzahrani
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - William R Critchley
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Elton Zeqiraj
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Aysha Divan
- School of Molecular & Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Michael A Harrison
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | | |
Collapse
|
3
|
The other side of the coin: Positive view on the role of opioids in cancer. Eur J Pharmacol 2022; 923:174888. [PMID: 35367422 DOI: 10.1016/j.ejphar.2022.174888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/26/2022] [Accepted: 03/09/2022] [Indexed: 11/23/2022]
Abstract
Opioids have been used for medicinal purposes as an analgesic and recreational purposes as a euphorigenic throughout human history. Cancer patients are often treated with different doses of opioids concurrently with anti-cancer drugs for pain relief without exhibiting excessive adverse effects. The intersection of the biology of pain, opioid therapy, and disease progression represents the crux of the matters and is of potentially great importance in cancer care. For more than 20 years, multiple investigations have focused on the stimulatory effects of opioids on cancer cell growth, while in-depth studies on the inhibitory effects on cancer cell growth development have usually been neglected. This paper reviews the evidence regarding opioid therapies and their anti-cancer effects on various malignancies. Likewise, we have a glimpse into the molecular mechanisms necessary for pinpointing their positive or negative impacts on malignancies to raise awareness and stimulate more excellent dialogue regarding their carcinogenic/anticarcinogenic roles.
Collapse
|
4
|
Wang H, Yang L, Liu M, Luo J. Protein post-translational modifications in the regulation of cancer hallmarks. Cancer Gene Ther 2022; 30:529-547. [PMID: 35393571 DOI: 10.1038/s41417-022-00464-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 02/28/2022] [Accepted: 03/18/2022] [Indexed: 12/12/2022]
Abstract
Posttranslational modifications (PTMs) of proteins, the major mechanism of protein function regulation, play important roles in regulating a variety of cellular physiological and pathological processes. Although the classical PTMs, such as phosphorylation, acetylation, ubiquitination and methylation, have been well studied, the emergence of many new modifications, such as succinylation, hydroxybutyrylation, and lactylation, introduces a new layer to protein regulation, leaving much more to be explored and wide application prospects. In this review, we will provide a broad overview of the significant roles of PTMs in regulating human cancer hallmarks through selecting a diverse set of examples, and update the current advances in the therapeutic implications of these PTMs in human cancer.
Collapse
Affiliation(s)
- Haiying Wang
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, 100191, Beijing, China.
| | - Liqian Yang
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, 100191, Beijing, China
| | - Minghui Liu
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, 100191, Beijing, China
| | - Jianyuan Luo
- Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, 100191, Beijing, China. .,Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, 100191, Beijing, China.
| |
Collapse
|
5
|
βIV-spectrin as a stalk cell-intrinsic regulator of VEGF signaling. Nat Commun 2022; 13:1326. [PMID: 35288568 PMCID: PMC8921520 DOI: 10.1038/s41467-022-28933-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022] Open
Abstract
Defective angiogenesis underlies over 50 malignant, ischemic and inflammatory disorders yet long-term therapeutic applications inevitably fail, thus highlighting the need for greater understanding of the vast crosstalk and compensatory mechanisms. Based on proteomic profiling of angiogenic endothelial components, here we report βIV-spectrin, a non-erythrocytic cytoskeletal protein, as a critical regulator of sprouting angiogenesis. Early loss of endothelial-specific βIV-spectrin promotes embryonic lethality in mice due to hypervascularization and hemorrhagic defects whereas neonatal depletion yields higher vascular density and tip cell populations in developing retina. During sprouting, βIV-spectrin expresses in stalk cells to inhibit their tip cell potential by enhancing VEGFR2 turnover in a manner independent of most cell-fate determining mechanisms. Rather, βIV-spectrin recruits CaMKII to the plasma membrane to directly phosphorylate VEGFR2 at Ser984, a previously undefined phosphoregulatory site that strongly induces VEGFR2 internalization and degradation. These findings support a distinct spectrin-based mechanism of tip-stalk cell specification during vascular development. Defective angiogenesis remains a high source of morbidity in multiple disorders. Here they show that βIV-spectrin, a membrane-associated cytoskeletal protein, is essential for regulation of endothelial tip cell populations and VEGF signaling during sprouting angiogenesis.
Collapse
|
6
|
Opioid receptors beyond pain control: The role in cancer pathology and the debated importance of their pharmacological modulation. Pharmacol Res 2020; 159:104938. [DOI: 10.1016/j.phrs.2020.104938] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/24/2020] [Accepted: 05/15/2020] [Indexed: 12/15/2022]
|
7
|
Zhu JW, Ni YJ, Tong XY, Guo X, Wu XP. Activation of VEGF receptors in response to UVB promotes cell proliferation and melanogenesis of normal human melanocytes. Exp Cell Res 2019; 387:111798. [PMID: 31874175 DOI: 10.1016/j.yexcr.2019.111798] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/13/2019] [Accepted: 12/20/2019] [Indexed: 11/29/2022]
Abstract
VEGF receptors (VEGFRs) are high-affinity receptors for VEGF and signaling via VEGFRs extends beyond the classical roles in blood vessel formation. We previously showed VEGFRs were also expressed in epidermal keratinocytes and activation of VEGFR-2 by ultraviolet B (UVB) was involved in the pro-survival mechanism. Here, we show that both VEGF165 and UVB enhanced the expression of VEGFRs (including VEGFR-1, VEGFR-2 and NRP-1) in normal human melanocytes, and increased expression of VEGFRs by UVB was mediated through hypoxia and oxidative stress. Also, VEGF165 and UVB promoted tyrosine phosphorylation of VEGFR-1 and VEGFR-2, and UVB-induced phosphorylation of VEGFR-1 and VEGFR-2 required PKA but not P38 MAPK. In addition, UVB and VEGF165 contributed to the over-expression of melanogenic proteins in melanocytes, which could be reduced by neutralization of VEGFR-1 and/or VEGFR-2. UVB, but not VEGF165 promoted cell proliferation, while neutralization of VEGFR-1 and/or VEGFR-2 abolished this effect. UVB showed stronger than VEGF165 in promoting tyrosinase activity and melanin production, while neutralization of VEGFR-2 was stronger in reducing these effects than that of VEGFR-1. Furthermore, tranexamic acid (TA) decreased tyrosinase activity and melanin production via inhibiting activation of VEGFRs and subsequent expression of melanogenic proteins in melanocytes. Taken together, we demonstrate that VEGFRs are functionally involved in UVB-induced melanogenesis, and TA can inhibit melanogenesis at least in part by targeting VEGFRs in melanocytes.
Collapse
Affiliation(s)
- Jian-Wei Zhu
- Department of Dermatology, Zhejiang Hospital, No. 12, Lingyin Rd., Hangzhou, 310013, Zhejiang Province, China.
| | - Ya-Jie Ni
- Department of Dermatology, Zhejiang Hospital, No. 12, Lingyin Rd., Hangzhou, 310013, Zhejiang Province, China
| | - Xiao-Yun Tong
- Department of Dermatology, Zhejiang Hospital, No. 12, Lingyin Rd., Hangzhou, 310013, Zhejiang Province, China
| | - Xia Guo
- Department of Dermatology, Zhejiang Hospital, No. 12, Lingyin Rd., Hangzhou, 310013, Zhejiang Province, China
| | - Xiao-Ping Wu
- Department of Dermatology, Zhejiang Hospital, No. 12, Lingyin Rd., Hangzhou, 310013, Zhejiang Province, China
| |
Collapse
|
8
|
Wang Y, Hoeppner LH, Angom RS, Wang E, Dutta S, Doeppler HR, Wang F, Shen T, Scarisbrick IA, Guha S, Storz P, Bhattacharya R, Mukhopadhyay D. Protein kinase D up-regulates transcription of VEGF receptor-2 in endothelial cells by suppressing nuclear localization of the transcription factor AP2β. J Biol Chem 2019; 294:15759-15767. [PMID: 31492751 PMCID: PMC6816101 DOI: 10.1074/jbc.ra119.010152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/19/2019] [Indexed: 01/29/2023] Open
Abstract
Vascular endothelial growth factor A (VEGF) signals primarily through its cognate receptor VEGF receptor-2 (VEGFR-2) to control vasculogenesis and angiogenesis, key physiological processes in cardiovascular disease and cancer. In human umbilical vein endothelial cells (HUVECs), knockdown of protein kinase D-1 (PKD1) or PKD2 down-regulates VEGFR-2 expression and inhibits VEGF-induced cell proliferation and migration. However, how PKD regulates VEGF signaling is unclear. Previous bioinformatics analyses have identified binding sites for the transcription factor activating enhancer-binding protein 2 (AP2) in the VEGFR-2 promoter. Using ChIP analyses, here we found that PKD knockdown in HUVECs increases binding of AP2β to the VEGFR-2 promoter. Luciferase reporter assays with serial deletions of AP2-binding sites within the VEGFR-2 promoter revealed that its transcriptional activity negatively correlates with the number of these sites. Next we demonstrated that AP2β up-regulation decreases VEGFR-2 expression and that loss of AP2β enhances VEGFR-2 expression in HUVECs. In vivo experiments confirmed increased VEGFR-2 immunostaining in the spinal cord of AP2β knockout mouse embryos. Mechanistically, we observed that PKD phosphorylates AP2β at Ser258 and Ser277 and suppresses its nuclear accumulation. Inhibition of PKD activity with a pan-PKD inhibitor increased AP2β nuclear localization, and overexpression of both WT and constitutively active PKD1 or PKD2 reduced AP2β nuclear localization through a Ser258- and Ser277-dependent mechanism. Furthermore, substitution of Ser277 in AP2β increased its binding to the VEGFR-2 promoter. Our findings uncover evidence of a molecular pathway that regulates VEGFR-2 expression, insights that may shed light on the etiology of diseases associated with aberrant VEGF/VEGFR signaling.
Collapse
Affiliation(s)
- Ying Wang
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Luke H Hoeppner
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Rochester, Minnesota 55905
| | - Ramcharan Singh Angom
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Enfeng Wang
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Shamit Dutta
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Heike R Doeppler
- Department of Cancer Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Fei Wang
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
- Department of Neurosurgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, China
| | - Tao Shen
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
- Department of Colorectal Surgery, Third Affiliated Hospital of Kunming Medical University, Kunming 650221, China
| | - Isobel A Scarisbrick
- Department of Physical Medicine and Rehabilitation, College of Medicine and Science, Mayo Clinic, Rochester, Minnesota 55905
| | - Sushovan Guha
- University of Arizona College of Medicine, Phoenix, Arizona 85004
| | - Peter Storz
- Department of Cancer Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| | - Resham Bhattacharya
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Rochester, Minnesota 55905
| | - Debabrata Mukhopadhyay
- Department of Biochemistry and Molecular Biology, College of Medicine and Science, Mayo Clinic, Jacksonville, Florida 32224
| |
Collapse
|
9
|
Opioids: Modulators of angiogenesis in wound healing and cancer. Oncotarget 2018; 8:25783-25796. [PMID: 28445930 PMCID: PMC5421968 DOI: 10.18632/oncotarget.15419] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/07/2017] [Indexed: 12/12/2022] Open
Abstract
Opioids are potent drugs that are widely used to control wound or cancer pain. Increasing evidence suggest that opioids mediate clinically relevant effects that go beyond their classical role as analgesics. Of note, opioids appear to modulate angiogenesis - a process that is critical in wound healing and cancer progression. In this review, we focus on pro- and anti-angiogenic facets of opioids that arise from the activation of individual opioid receptors and the usage of individual concentrations or application routes. We overview the still incompletely elucidated mechanisms of these angiogenic opioid actions. Moreover, we describe plausible opioids effects, which - although not primarily studied in the context of vessel formation - may be related to the opioid-driven processes of angiogenesis. Finally we discuss the use of opioids as an innovative therapeutic avenue for the treatment of chronic wounds and cancer.
Collapse
|
10
|
Xie W, Liu C, Wu D, Li Z, Li C, Zhang Y. Phosphorylation of kinase insert domain receptor by cyclin-dependent kinase 5 at serine 229 is associated with invasive behavior and poor prognosis in prolactin pituitary adenomas. Oncotarget 2018; 7:50883-50894. [PMID: 27438154 PMCID: PMC5239444 DOI: 10.18632/oncotarget.10550] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 06/29/2016] [Indexed: 12/18/2022] Open
Abstract
Pituitary adenomas constitute 15-20% of intracranial neoplasms. Previously we reported that cyclin-dependent kinase 5 (CDK5) is upregulated in pituitary tumors associated with activating protein p35, and plays an essential role in pituitary adenomas progression. Here we explored the mechanisms of CDK5 signaling in prolactin pituitary adenomas. Our data indicate that p35 expression and CDK5 activity are both significantly increased in human invasive prolactin pituitary adenomas as compared to noninvasive forms of pituitary adenomas. Inhibition of CDK5 activity suppressed cell migration and invasive ability in GH3 rat pituitary cells. We identified that CDK5 phosphorylates serine 229 residue (Ser-229) of kinase insert domain receptor (KDR), also known as VEGFR-2, in prolactin pituitary adenomas. Phosphorylation of Ser-229 is required for proper KDR surface localization. Phosphorylated Ser-229 in KDR (pSer-229) levels are significantly higher in noninvasive and invasive prolactin pituitary adenomas compared to normal pituitary tissues. In addition, our data indicated that higher KDR pSer-229 correlates with worse prognosis in patients with prolactin pituitary adenomas. In summary, our results illustrated that CDK5-mediated KDR phosphorylation controls prolactin pituitary adenoma progression and KDR pSer-229 serves as a potential prognostic biomarker for both noninvasive and invasive pituitary adenomas.
Collapse
Affiliation(s)
- Weiyan Xie
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chunhui Liu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Dan Wu
- Neurological Department, Beijing Renhe Hospital, Beijing, China
| | - Zhenye Li
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chuzhong Li
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yazhuo Zhang
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
11
|
Tian Y, Gawlak G, O'Donnell JJ, Birukova AA, Birukov KG. Activation of Vascular Endothelial Growth Factor (VEGF) Receptor 2 Mediates Endothelial Permeability Caused by Cyclic Stretch. J Biol Chem 2016; 291:10032-45. [PMID: 26884340 DOI: 10.1074/jbc.m115.690487] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Indexed: 01/28/2023] Open
Abstract
High tidal volume mechanical ventilation and the resultant excessive mechanical forces experienced by lung vascular endothelium are known to lead to increased vascular endothelial leak, but the underlying molecular mechanisms remain incompletely understood. One reported mechanotransduction pathway of increased endothelial cell (EC) permeability caused by high magnitude cyclic stretch (18% CS) involves CS-induced activation of the focal adhesion associated signalosome, which triggers Rho GTPase signaling. This study identified an alternative pathway of CS-induced EC permeability. We show here that high magnitude cyclic stretch (18% CS) rapidly activates VEGF receptor 2 (VEGFR2) signaling by dissociating VEGFR2 from VE-cadherin at the cell junctions. This results in VEGFR2 activation, Src-dependent VE-cadherin tyrosine phosphorylation, and internalization leading to increased endothelial permeability. This process is also accompanied by CS-induced phosphorylation and internalization of PECAM1. Importantly, CS-induced endothelial barrier disruption was attenuated by VEGFR2 inhibition. 18% CS-induced EC permeability was linked to dissociation of cell junction scaffold afadin from the adherens junctions. Forced expression of recombinant afadin in pulmonary endothelium attenuated CS-induced VEGFR2 and VE-cadherin phosphorylation, preserved adherens junction integrity and VEGFR2·VE-cadherin complex, and suppressed CS-induced EC permeability. This study shows for the first time a mechanism whereby VEGFR2 activation mediates EC permeability induced by pathologically relevant cyclic stretch. In this mechanism, CS induces dissociation of the VE-cadherin·VEGFR2 complex localized at the adherens juctions, causing activation of VEGFR2, VEGFR2-mediated Src-dependent phosphorylation of VE-cadherin, disassembly of adherens junctions, and EC barrier failure.
Collapse
Affiliation(s)
- Yufeng Tian
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Grzegorz Gawlak
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - James J O'Donnell
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Anna A Birukova
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| | - Konstantin G Birukov
- From the Lung Injury Center and Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637
| |
Collapse
|
12
|
Smith G, Tomlinson D, Harrison M, Ponnambalam S. Chapter Eight - Ubiquitin-Mediated Regulation of Cellular Responses to Vascular Endothelial Growth Factors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:313-38. [DOI: 10.1016/bs.pmbts.2016.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
13
|
Srinivasan S, Chitalia V, Meyer RD, Hartsough E, Mehta M, Harrold I, Anderson N, Feng H, Smith LEH, Jiang Y, Costello CE, Rahimi N. Hypoxia-induced expression of phosducin-like 3 regulates expression of VEGFR-2 and promotes angiogenesis. Angiogenesis 2015; 18:449-62. [PMID: 26059764 PMCID: PMC4600037 DOI: 10.1007/s10456-015-9468-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 05/04/2015] [Indexed: 12/18/2022]
Abstract
Expression and activation of vascular endothelial growth factor receptor 2 (VEGFR-2) by VEGF ligands are the main events in the stimulation of pathological angiogenesis. VEGFR-2 expression is generally low in the healthy adult blood vessels, but its expression is markedly increased in the pathological angiogenesis. In this report, we demonstrate that phosducin-like 3 (PDCL3), a recently identified chaperone protein involved in the regulation of VEGFR-2 expression, is required for angiogenesis in zebrafish and mouse. PDCL3 undergoes N-terminal methionine acetylation, and this modification affects PDCL3 expression and its interaction with VEGFR-2. Expression of PDCL3 is regulated by hypoxia, the known stimulator of angiogenesis. The mutant PDCL3 that is unable to undergo N-terminal methionine acetylation was refractory to the effect of hypoxia. The siRNA-mediated silencing of PDCL3 decreased VEGFR-2 expression resulting in a decrease in VEGF-induced VEGFR-2 phosphorylation, whereas PDCL3 over-expression increased VEGFR-2 protein. Furthermore, we show that PDCL3 protects VEGFR-2 from misfolding and aggregation. The data provide new insights for the chaperone function of PDCL3 in angiogenesis and the roles of hypoxia and N-terminal methionine acetylation in PDCL3 expression and its effect on VEGFR-2.
Collapse
Affiliation(s)
- Srimathi Srinivasan
- Departments of Pathology and Ophthalmology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Vipul Chitalia
- Renal Section, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
| | - Rosana D Meyer
- Departments of Pathology and Ophthalmology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Edward Hartsough
- Departments of Pathology and Ophthalmology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Manisha Mehta
- Departments of Pathology and Ophthalmology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Itrat Harrold
- Section of Hematology and Medical Oncology, Department of Pharmacology and Experimental Therapeutics, The Center for Cancer Research, Boston University School of Medicine, Boston, MA, USA
| | - Nicole Anderson
- Section of Hematology and Medical Oncology, Department of Pharmacology and Experimental Therapeutics, The Center for Cancer Research, Boston University School of Medicine, Boston, MA, USA
| | - Hui Feng
- Section of Hematology and Medical Oncology, Department of Pharmacology and Experimental Therapeutics, The Center for Cancer Research, Boston University School of Medicine, Boston, MA, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yan Jiang
- Department of Biochemistry and Center for Biomedical Mass Spectrometry, School of Medicine, Boston University Medical Campus, Boston, MA, USA
| | - Catherine E Costello
- Department of Biochemistry and Center for Biomedical Mass Spectrometry, School of Medicine, Boston University Medical Campus, Boston, MA, USA
| | - Nader Rahimi
- Departments of Pathology and Ophthalmology, Boston University School of Medicine, Boston, MA, 02118, USA.
- Department of Pathology, Boston University Medical Campus, 670 Albany St., Room 510, Boston, MA, 02118, USA.
| |
Collapse
|
14
|
The cellular response to vascular endothelial growth factors requires co-ordinated signal transduction, trafficking and proteolysis. Biosci Rep 2015; 35:BSR20150171. [PMID: 26285805 PMCID: PMC4613718 DOI: 10.1042/bsr20150171] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/18/2015] [Indexed: 01/18/2023] Open
Abstract
VEGFs (vascular endothelial growth factors) are a family of conserved disulfide-linked soluble secretory glycoproteins found in higher eukaryotes. VEGFs mediate a wide range of responses in different tissues including metabolic homoeostasis, cell proliferation, migration and tubulogenesis. Such responses are initiated by VEGF binding to soluble and membrane-bound VEGFRs (VEGF receptor tyrosine kinases) and co-receptors. VEGF and receptor splice isoform diversity further enhances complexity of membrane protein assembly and function in signal transduction pathways that control multiple cellular responses. Different signal transduction pathways are simultaneously activated by VEGFR-VEGF complexes with membrane trafficking along the endosome-lysosome network further modulating signal output from multiple enzymatic events associated with such pathways. Balancing VEGFR-VEGF signal transduction with trafficking and proteolysis is essential in controlling the intensity and duration of different intracellular signalling events. Dysfunction in VEGF-regulated signal transduction is important in chronic disease states including cancer, atherosclerosis and blindness. This family of growth factors and receptors is an important model system for understanding human disease pathology and developing new therapeutics for treating such ailments.
Collapse
|
15
|
Teran M, Nugent MA. Synergistic Binding of Vascular Endothelial Growth Factor-A and Its Receptors to Heparin Selectively Modulates Complex Affinity. J Biol Chem 2015; 290:16451-62. [PMID: 25979342 DOI: 10.1074/jbc.m114.627372] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Indexed: 01/13/2023] Open
Abstract
Angiogenesis is a highly regulated process orchestrated by the VEGF system. Heparin/heparan sulfate proteoglycans and neuropilin-1 (NRP-1) have been identified as co-receptors, yet the mechanisms of action have not been fully defined. In the present study, we characterized molecular interactions between receptors and co-receptors, using surface plasmon resonance and in vitro binding assays. Additionally, we demonstrate that these binding events are relevant to VEGF activity within endothelial cells. We defined interactions and structural requirements for heparin/HS interactions with VEGF receptor (VEGFR)-1, NRP-1, and VEGF165 in complex with VEGFR-2 and NRP-1. We demonstrate that these structural requirements are distinct for each interaction. We further show that VEGF165, VEGFR-2, and monomeric NRP-1 bind weakly to heparin alone yet show synergistic binding to heparin when presented together in various combinations. This synergistic binding appears to translate to alterations in VEGF signaling in endothelial cells. We found that soluble NRP-1 increases VEGF binding and activation of VEGFR-2 and ERK1/2 in endothelial cells and that these effects require sulfated HS. These data suggest that the presence of HS/heparin and NRP-1 may dictate the specific receptor type activated by VEGF and ultimately determine the biological output of the system. The ability of co-receptors to fine-tune VEGF responsiveness suggests the possibility that VEGF-mediated angiogenesis can be selectively stimulated or inhibited by targeting HS/heparin and NRP-1.
Collapse
Affiliation(s)
- Madelane Teran
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118 and
| | - Matthew A Nugent
- the Department of Biological Sciences, University of Massachusetts Lowell, Lowell, Massachusetts 01854
| |
Collapse
|
16
|
Rahimi N, Costello CE. Emerging roles of post-translational modifications in signal transduction and angiogenesis. Proteomics 2014; 15:300-9. [PMID: 25161153 DOI: 10.1002/pmic.201400183] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/14/2014] [Accepted: 08/20/2014] [Indexed: 01/02/2023]
Abstract
The vascular endothelial growth factor receptor-2 (VEGFR-2) belongs to the family of receptor tyrosine kinases and is a key player in vasculogenesis and pathological angiogenesis. An emerging picture of PTMs of VEGFR-2 suggests that they play central roles in generating a highly dynamic and complex signaling system that regulates key angiogenic responses ranging from endothelial cell differentiation, proliferation, migration to permeability. Recent MS analysis of VEGFR-2 uncovered previously unrecognized PTMs on VEGFR-2 with a distinct function. The ligand binding extracellular domain of VEGFR-2 is composed of seven immunoglobulin-like domains highly decorated with N-glycosylation, while its cytoplasmic domain is subject to multiple PTMs including Tyr, Ser/Thr phosphorylation, Arg and Lys methylation, acetylation and ubiquitination. Here we review the PTMs on VEGFR-2, their importance in angiogenic signaling relays and possible novel therapeutic potentials.
Collapse
Affiliation(s)
- Nader Rahimi
- Department of Pathology, Boston University School of Medicine, Boston, MA, USA
| | | |
Collapse
|
17
|
Wang T, Li R, Lin C, Sun M, Kang YJ. Brief Communication: Copper suppression of vascular endothelial growth factor receptor-2 is involved in the regression of cardiomyocyte hypertrophy. Exp Biol Med (Maywood) 2014; 239:948-953. [PMID: 24903162 DOI: 10.1177/1535370214536119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Previous studies revealed that copper (Cu)-induced regression of cardiomyocyte hypertrophy is associated with enhanced activity in the vascular endothelial growth factor receptor-1 (VEGFR-1) signaling pathway. The mechanism by which Cu enhances the activity of VEGFR-1 pathway remains to be defined. The present study was undertaken to test the hypothesis that Cu enhances the VEGFR-1 signaling pathway via suppression of the VEGFR-2 signaling pathway. Primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 µM in cultures for 48 h to induce cell hypertrophy. The hypertrophic cardiomyocytes were exposed to copper sulfate at a final concentration of 5 µM Cu in cultures for 24 h. Western blot analysis showed that PE increased the protein levels of both VEGFR-1 and VEGFR-2. Cu supplementation significantly reduced the increase in VEGFR-2, but had no effect on the elevation of VEGFR-1. Real-time polymerase chain reaction analysis found no difference in the mRNA levels between the VEGFR-1 and VEGFR-2 under the conditions defined above. This study thus demonstrated that Cu selectively suppressed PE-elevated VEGFR-2 levels likely via post-translational regulation, leading to the VEGFR-1 signaling pathway becoming dominant and thereby regressing cardiomyocyte hypertrophy.
Collapse
Affiliation(s)
- Tao Wang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Rui Li
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Chen Lin
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Miao Sun
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Y James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| |
Collapse
|
18
|
Hartsough EJ, Meyer RD, Chitalia V, Jiang Y, Marquez VE, Zhdanova IV, Weinberg J, Costello CE, Rahimi N. Lysine methylation promotes VEGFR-2 activation and angiogenesis. Sci Signal 2013; 6:ra104. [PMID: 24300896 PMCID: PMC4108444 DOI: 10.1126/scisignal.2004289] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Activation of vascular endothelial growth factor receptor-2 (VEGFR-2), an endothelial cell receptor tyrosine kinase, promotes tumor angiogenesis and ocular neovascularization. We report the methylation of VEGFR-2 at multiple Lys and Arg residues, including Lys(1041), a residue that is proximal to the activation loop of the kinase domain. Methylation of VEGFR-2 was independent of ligand binding and was not regulated by ligand stimulation. Methylation of Lys(1041) enhanced tyrosine phosphorylation and kinase activity in response to ligands. Additionally, interfering with the methylation of VEGFR-2 by pharmacological inhibition or by site-directed mutagenesis revealed that methylation of Lys(1041) was required for VEGFR-2-mediated angiogenesis in zebrafish and tumor growth in mice. We propose that methylation of Lys(1041) promotes the activation of VEGFR-2 and that similar posttranslational modification could also regulate the activity of other receptor tyrosine kinases.
Collapse
Affiliation(s)
- Edward J. Hartsough
- Departments of Pathology and Ophthalmology, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| | - Rosana D. Meyer
- Departments of Pathology and Ophthalmology, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| | - Vipul Chitalia
- Harvard-MIT Division of Health Science and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yan Jiang
- Department of Biochemistry and Center for Biomedical Mass Spectrometry, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| | - Victor E. Marquez
- Chemical Biology Laboratory, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Irina V. Zhdanova
- Department of Anatomy and Neurobiology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Janice Weinberg
- School of Public Health, Boston University Medical Campus, Boston, MA 02118, USA
| | - Catherine E. Costello
- Department of Biochemistry and Center for Biomedical Mass Spectrometry, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| | - Nader Rahimi
- Departments of Pathology and Ophthalmology, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| |
Collapse
|
19
|
Hartsough EJ, Meyer RD, Chitalia V, Jiang Y, Marquez VE, Zhdanova IV, Weinberg J, Costello CE, Rahimi N. Lysine methylation promotes VEGFR-2 activation and angiogenesis. Sci Signal 2013. [PMID: 24300896 DOI: 10.1126/scisignal.200415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
Activation of vascular endothelial growth factor receptor-2 (VEGFR-2), an endothelial cell receptor tyrosine kinase, promotes tumor angiogenesis and ocular neovascularization. We report the methylation of VEGFR-2 at multiple Lys and Arg residues, including Lys(1041), a residue that is proximal to the activation loop of the kinase domain. Methylation of VEGFR-2 was independent of ligand binding and was not regulated by ligand stimulation. Methylation of Lys(1041) enhanced tyrosine phosphorylation and kinase activity in response to ligands. Additionally, interfering with the methylation of VEGFR-2 by pharmacological inhibition or by site-directed mutagenesis revealed that methylation of Lys(1041) was required for VEGFR-2-mediated angiogenesis in zebrafish and tumor growth in mice. We propose that methylation of Lys(1041) promotes the activation of VEGFR-2 and that similar posttranslational modification could also regulate the activity of other receptor tyrosine kinases.
Collapse
Affiliation(s)
- Edward J Hartsough
- 1Departments of Pathology and Ophthalmology, School of Medicine, Boston University Medical Campus, Boston, MA 02118, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Koch S, Claesson-Welsh L. Signal transduction by vascular endothelial growth factor receptors. Cold Spring Harb Perspect Med 2013; 2:a006502. [PMID: 22762016 DOI: 10.1101/cshperspect.a006502] [Citation(s) in RCA: 595] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vascular endothelial growth factors (VEGFs) are master regulators of vascular development and of blood and lymphatic vessel function during health and disease in the adult. It is therefore important to understand the mechanism of action of this family of five mammalian ligands, which act through three receptor tyrosine kinases (RTKs). In addition, coreceptors like neuropilins (NRPs) and integrins associate with the ligand/receptor signaling complex and modulate the output. Therapeutics to block several of the VEGF signaling components have been developed with the aim to halt blood vessel formation, angiogenesis, in diseases that involve tissue growth and inflammation, such as cancer. In this review, we outline the current information on VEGF signal transduction in relation to blood and lymphatic vessel biology.
Collapse
Affiliation(s)
- Sina Koch
- Uppsala University, Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, 751 85 Uppsala, Sweden
| | | |
Collapse
|
21
|
Srinivasan S, Meyer RD, Lugo R, Rahimi N. Identification of PDCL3 as a novel chaperone protein involved in the generation of functional VEGF receptor 2. J Biol Chem 2013; 288:23171-81. [PMID: 23792958 DOI: 10.1074/jbc.m113.473173] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Angiogenesis, a hallmark step in tumor metastasis and ocular neovascularization, is driven primarily by the function of VEGF ligand on one of its receptors, VEGF receptor 2 (VEGFR-2). Central to the proliferation and ensuing angiogenesis of endothelial cells, the abundance of VEGFR-2 on the surface of endothelial cells is essential for VEGF to recognize and activate VEGFR-2. We have identified phosducin-like 3 (PDCL3, also known as PhLP2A), through a yeast two-hybrid system, as a novel protein involved in the stabilization of VEGFR-2 by serving as a chaperone. PDCL3 binds to the juxtamembrane domain of VEGFR-2 and controls the abundance of VEGFR-2 by inhibiting its ubiquitination and degradation. PDCL3 increases VEGF-induced tyrosine phosphorylation and is required for VEGFR-2-dependent endothelial capillary tube formation and proliferation. Taken together, our data provide strong evidence for the role of PDCL3 in angiogenesis and establishes the molecular mechanism by which it regulates VEGFR-2 expression and function.
Collapse
Affiliation(s)
- Srimathi Srinivasan
- Department of Pathology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | | | | |
Collapse
|
22
|
Most P, Lerchenmüller C, Rengo G, Mahlmann A, Ritterhoff J, Rohde D, Goodman C, Busch CJ, Laube F, Heissenberg J, Pleger ST, Weiss N, Katus HA, Koch WJ, Peppel K. S100A1 deficiency impairs postischemic angiogenesis via compromised proangiogenic endothelial cell function and nitric oxide synthase regulation. Circ Res 2012; 112:66-78. [PMID: 23048072 DOI: 10.1161/circresaha.112.275156] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
RATIONALE Mice lacking the EF-hand Ca2+ sensor S100A1 display endothelial dysfunction because of distorted Ca2+ -activated nitric oxide (NO) generation. OBJECTIVE To determine the pathophysiological role of S100A1 in endothelial cell (EC) function in experimental ischemic revascularization. METHODS AND RESULTS Patients with chronic critical limb ischemia showed almost complete loss of S100A1 expression in hypoxic tissue. Ensuing studies in S100A1 knockout (SKO) mice subjected to femoral artery resection unveiled insufficient perfusion recovery and high rates of autoamputation. Defective in vivo angiogenesis prompted cellular studies in SKO ECs and human ECs, with small interfering RNA-mediated S100A1 knockdown demonstrating impaired in vitro and in vivo proangiogenic properties (proliferation, migration, tube formation) and attenuated vascular endothelial growth factor (VEGF)-stimulated and hypoxia-stimulated endothelial NO synthase (eNOS) activity. Mechanistically, S100A1 deficiency compromised eNOS activity in ECs by interrupted stimulatory S100A1/eNOS interaction and protein kinase C hyperactivation that resulted in inhibitory eNOS phosphorylation and enhanced VEGF receptor-2 degradation with attenuated VEGF signaling. Ischemic SKO tissue recapitulated the same molecular abnormalities with insufficient in vivo NO generation. Unresolved ischemia entailed excessive VEGF accumulation in SKO mice with aggravated VEGF receptor-2 degradation and blunted in vivo signaling through the proangiogenic phosphoinositide-3-kinase/Akt/eNOS cascade. The NO supplementation strategies rescued defective angiogenesis and salvaged limbs in SKO mice after femoral artery resection. CONCLUSIONS Our study shows for the first time downregulation of S100A1 expression in patients with critical limb ischemia and identifies S100A1 as critical for EC function in postnatal ischemic angiogenesis. These findings link its pathological plasticity in critical limb ischemia to impaired neovascularization, prompting further studies to probe the microvascular therapeutic potential of S100A1.
Collapse
Affiliation(s)
- Patrick Most
- Center for Molecular and Translational Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Shaik S, Nucera C, Inuzuka H, Gao D, Garnaas M, Frechette G, Harris L, Wan L, Fukushima H, Husain A, Nose V, Fadda G, Sadow PM, Goessling W, North T, Lawler J, Wei W. SCF(β-TRCP) suppresses angiogenesis and thyroid cancer cell migration by promoting ubiquitination and destruction of VEGF receptor 2. ACTA ACUST UNITED AC 2012; 209:1289-307. [PMID: 22711876 PMCID: PMC3405505 DOI: 10.1084/jem.20112446] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The E3 ubiquitin ligase β-TRCP, acting in concert with casein kinase I, drives ubiquitination and degradation of VEGFR2, and renders human papillary thyroid cancer cells resistant to the VEGFR2 inhibitor sorafenib. The incidence of human papillary thyroid cancer (PTC) is increasing and an aggressive subtype of this disease is resistant to treatment with vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor. VEGFR2 promotes angiogenesis by triggering endothelial cell proliferation and migration. However, the molecular mechanisms governing VEGFR2 stability in vivo remain unknown. Additionally, whether VEGFR2 influences PTC cell migration is not clear. We show that the ubiquitin E3 ligase SCFβ-TRCP promotes ubiquitination and destruction of VEGFR2 in a casein kinase I (CKI)–dependent manner. β-TRCP knockdown or CKI inhibition causes accumulation of VEGFR2, resulting in increased activity of signaling pathways downstream of VEGFR2. β-TRCP–depleted endothelial cells exhibit enhanced migration and angiogenesis in vitro. Furthermore, β-TRCP knockdown increased angiogenesis and vessel branching in zebrafish. Importantly, we found an inverse correlation between β-TRCP protein levels and angiogenesis in PTC. We also show that β-TRCP inhibits cell migration and decreases sensitivity to the VEGFR2 inhibitor sorafenib in poorly differentiated PTC cells. These results provide a new biomarker that may aid a rational use of tyrosine kinase inhibitors to treat refractory PTC.
Collapse
Affiliation(s)
- Shavali Shaik
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
A strict physiological balance between endogenous proangiogenic and antiangiogenic factors controls endothelial cell functions, such that endothelial cell growth is normally restrained. However, in pathologic angiogenesis, a shift occurs in the balance of regulators, favoring endothelial growth. Much of the control of angiogenic events is instigated through hypoxia-induced VEGF expression. The ubiquitin-proteasome system (UPS) plays a central role in fine-tuning the functions of core proangiogenic proteins, including VEGF, VEGFR-2, angiogenic signaling proteins (e.g., the PLCγ1 and PI3 kinase/AKT pathways), and other non-VEGF angiogenic pathways. The emerging mechanisms by which ubiquitin modification of angiogenic proteins control angiogenesis involve both proteolytic and nonproteolytic functions. Here, I review recent advances that link the UPS to regulation of angiogenesis and highlight the potential therapeutic value of the UPS in angiogenesis-associated diseases.
Collapse
Affiliation(s)
- Nader Rahimi
- Department of Pathology, Boston University Medical Campus, 670 Albany St., Room 510, Boston, MA 02118, USA.
| |
Collapse
|
25
|
Activation of VEGFR-2 signaling in response to moderate dose of ultraviolet B promotes survival of normal human keratinocytes. Int J Biochem Cell Biol 2012; 44:246-56. [DOI: 10.1016/j.biocel.2011.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 09/24/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
|
26
|
Domingues I, Rino J, Demmers JAA, de Lanerolle P, Santos SCR. VEGFR2 translocates to the nucleus to regulate its own transcription. PLoS One 2011; 6:e25668. [PMID: 21980525 PMCID: PMC3182252 DOI: 10.1371/journal.pone.0025668] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 09/09/2011] [Indexed: 01/01/2023] Open
Abstract
Vascular Endothelial Growth Factor Receptor-2 (VEGFR2) is the major mediator of the angiogenic effects of VEGF. In addition to its well known role as a membrane receptor that activates multiple signaling pathways, VEGFR2 also has a nuclear localization. However, what VEGFR2 does in the nucleus is still unknown. In the present report we show that, in endothelial cells, nuclear VEGFR2 interacts with several nuclear proteins, including the Sp1, a transcription factor that has been implicated in the regulation of genes needed for angiogenesis. By in vivo chromatin immunoprecipitation (ChIP) assays, we found that VEGFR2 binds to the Sp1-responsive region of the VEGFR2 proximal promoter. These results were confirmed by EMSA assays, using the same region of the VEGFR2 promoter. Importantly, we show that the VEGFR2 DNA binding is directly linked to the transcriptional activation of the VEGFR2 promoter. By reporter assays, we found that the region between -300/-116 relative to the transcription start site is essential to confer VEGFR2-dependent transcriptional activity. It was previously described that nuclear translocation of the VEGFR2 is dependent on its activation by VEGF. In agreement, we observed that the binding of VEGFR2 to DNA requires VEGF activation, being blocked by Bevacizumab and Sunitinib, two anti-angiogenic agents that inhibit VEGFR2 activation. Our findings demonstrate a new mechanism by which VEGFR2 activates its own promoter that could be involved in amplifying the angiogenic response.
Collapse
Affiliation(s)
- Inês Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - José Rino
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Jeroen A. A. Demmers
- Proteomics Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Primal de Lanerolle
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | | |
Collapse
|
27
|
Abstract
VEGFs (vascular endothelial growth factors) control vascular development during embryogenesis and the function of blood vessels and lymphatic vessels in the adult. There are five related mammalian ligands, which act through three receptor tyrosine kinases. Signalling is modulated through neuropilins, which act as VEGF co-receptors. Heparan sulfate and integrins are also important modulators of VEGF signalling. Therapeutic agents that interfere with VEGF signalling have been developed with the aim of decreasing angiogenesis in diseases that involve tissue growth and inflammation, such as cancer. The present review will outline the current understanding and consequent biology of VEGF receptor signalling.
Collapse
|
28
|
Boucher I, Kehasse A, Marcincin M, Rich C, Rahimi N, Trinkaus-Randall V. Distinct activation of epidermal growth factor receptor by UTP contributes to epithelial cell wound repair. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1092-105. [PMID: 21356361 DOI: 10.1016/j.ajpath.2010.11.060] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 10/13/2010] [Accepted: 11/23/2010] [Indexed: 01/05/2023]
Abstract
The release of nucleotides after injury activates purinergic receptors, leading to phosphorylation of site-specific residues on epidermal growth factor receptor (EGFR). To elucidate the differences between the injury-induced response and that induced by exogenous EGF, we examined recruitment of docking proteins, internalization of EGFR, and migration after injury. Injury induced by scratch wounds or stimulation by addition of UTP caused a brief internalization of EGFR, which paralleled the lesser association with growth factor receptor-bound protein 2 (Grb2) and phosphorylation of EGFR. The internalization caused by EGF was sustained and detected for longer than 60 minutes and correlated with phosphorylation of the receptor. The EGF caused recruitment of Grb2, phospholipase C-γ-1 (PLCγ1), Shc, and Src to EGFR. Glutathione S-transferase pull downs were performed, and glutathione S-transferase-PLCγ1 showed binding of Grb2 when stimulated with EGF but not with UTP or injury. Furthermore, UTP did not induce PLCγ1 phosphorylation, and the phosphorylation induced by EGF was attenuated by costimulation with UTP. The response to heparin-binding EGF was equivalent to that of EGF. Site-directed mutagenesis showed that phosphorylation of Y1068 and Y1086 of EGFR is required for repair. Together, our results show that injury and activation of purinergic receptors and direct activation of EGFR via EGF induce distinct downstream pathways.
Collapse
Affiliation(s)
- Ilene Boucher
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | | | | | | | | |
Collapse
|
29
|
PEST motif serine and tyrosine phosphorylation controls vascular endothelial growth factor receptor 2 stability and downregulation. Mol Cell Biol 2011; 31:2010-25. [PMID: 21402774 DOI: 10.1128/mcb.01006-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The internalization and degradation of vascular endothelial growth factor receptor 2 (VEGFR-2), a potent angiogenic receptor tyrosine kinase, is a central mechanism for the regulation of the coordinated action of VEGF in angiogenesis. Here, we show that VEGFR-2 is ubiquitinated in response to VEGF, and Lys 48-linked polyubiquitination controls its degradation via the 26S proteosome. The degradation and ubiquitination of VEGFR-2 is controlled by its PEST domain, and the phosphorylation of Ser1188/Ser1191 is required for the ubiquitination of VEGFR-2. F-box-containing β-Trcp1 ubiquitin E3 ligase is recruited to S1188/S1191 VEGFR-2 and mediates the ubiquitination and degradation of VEGFR-2. The PEST domain also controls the activation of p38 mitogen-activated protein kinase (MAPK) through phospho-Y1173. The activation of p38 stabilizes VEGFR-2, and its inactivation accelerates VEGFR-2 downregulation. The VEGFR-2-mediated activation of p38 is established through the protein kinase A (PKA)/MKK6 pathway. PKA is recruited to VEGFR-2 through AKAP1/AKAP149, and its phosphorylation requires Y1173 of VEGFR-2. The study has identified a unique mechanism in which VEGFR-2 stability and degradation is modulated. The PEST domain acts as a dual modulator of VEGFR-2; the phosphorylation of S1188/S1191 controls ubiquitination and degradation via β-Trcp1, where the phosphorylation of Y1173 through PKA/p38 MAPK controls the stability of VEGFR-2.
Collapse
|
30
|
Conditional HIF-1 induction produces multistage neovascularization with stage-specific sensitivity to VEGFR inhibitors and myeloid cell independence. Blood 2011; 117:4142-53. [PMID: 21307392 DOI: 10.1182/blood-2010-09-307538] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neovascularization is a crucial component of tumor growth and ischemia. Although prior work primarily used disease models, delineation of neovascularization in the absence of disease can reveal intrinsic mechanisms of microvessel regulation amenable to manipulation in illness. We created a conditional model of epithelial HIF-1 induction in adult mice (TetON-HIF-1 mice). Longitudinal photoacoustic microscopy (L-PAM) was coincidentally developed for noninvasive, label-free serial imaging of red blood cell-perfused vasculature in the same mouse for weeks to months. TetON-HIF-1 mice evidenced 3 stages of neovascularization: development, maintenance, and transgene-dependent regression. Regression occurred despite extensive and tight pericyte coverage. L-PAM mapped microvascular architecture and quantified volumetric changes in neocapillary morphogenesis, arteriovenous remodeling, and microvessel regression. Developmental stage endothelial proliferation down-regulation was associated with a DNA damage checkpoint consisting of p53, p21, and endothelial γ-H2AX induction. The neovasculature was temporally responsive to VEGFR2 immuno-blockade, with the developmental stage sensitive, and the maintenance stage resistant, to DC101 treatment. L-PAM analysis also pinpointed microvessels ablated or resistant to VEGFR2 immuno-blockade. HIF-1-recruited myeloid cells did not mediate VEGFR2 inhibitor resistance. Thus, HIF-1 neovascularization in the absence of disease is self-regulated via cell autonomous endothelial checkpoints, and resistant to angiogenesis inhibitors independent of myeloid cells.
Collapse
|
31
|
Meyer RD, Husain D, Rahimi N. c-Cbl inhibits angiogenesis and tumor growth by suppressing activation of PLCγ1. Oncogene 2011; 30:2198-206. [PMID: 21242968 PMCID: PMC3969724 DOI: 10.1038/onc.2010.597] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Angiogenesis is regulated by highly coordinated function of various proteins with pro- and anti-angiogenic functions. Among the many cytoplasmic signaling proteins that are activated by VEGFR-2, activation of PLCγ1 is considered to have a pivotal role in angiogenic signaling. In previous study we have identified c-Cbl as a negative regulator of PLCγ1 in endothelial cells, the biochemical and biological significance of c-Cbl, however, in angiogenesis in vivo and molecular mechanisms involved were remained elusive. In this study, we report that genetic inactivation of c-Cbl in mice results in enhanced tumor angiogenesis and retinal neovascularization. Endothelial cells derived from c-Cbl null mice displayed elevated cell proliferation and tube formation in response to VEGF stimulation. Loss of c-Cbl also resulted in robust activation of PLCγ1 and increased intracellular calcium release. c-Cbl-dependent ubiquitination selectively inhibited tyrosine phosphorylation of PLCγ1 and mostly refrained from ubiquitin-mediated degradation. Hence, we propose c-Cbl as an angiogenic suppressor protein where upon activation it uniquely modulates PLCγ1 activation by ubiquitination and subsequently inhibits VEGF-driven angiogenesis.
Collapse
Affiliation(s)
- R D Meyer
- Department of Pathology, Boston University Medical Campus, Boston, MA 02118, USA
| | | | | |
Collapse
|
32
|
Bahram F, Claesson-Welsh L. VEGF-mediated signal transduction in lymphatic endothelial cells. PATHOPHYSIOLOGY 2010; 17:253-61. [DOI: 10.1016/j.pathophys.2009.10.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 07/18/2009] [Accepted: 10/23/2009] [Indexed: 12/30/2022] Open
|
33
|
Liu J, Agarwal S. Mechanical signals activate vascular endothelial growth factor receptor-2 to upregulate endothelial cell proliferation during inflammation. THE JOURNAL OF IMMUNOLOGY 2010; 185:1215-21. [PMID: 20548028 DOI: 10.4049/jimmunol.0903660] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Signals generated by the dynamic mechanical strain critically regulate endothelial cell proliferation and angiogenesis; however, the molecular basis remains unclear. We investigated the mechanisms by which human dermal microvascular endothelial cells (HDMECs) perceive mechanical signals and relay them intracellularly to regulate gene expression and endothelial cell proliferation. HDMECs were exposed to low/physiologic levels of dynamic strain and probed for the differential activation/inhibition of kinases in the mechanosignaling cascade associated with endothelial cell gene activation. Because angiogenesis is important at inflammatory sites, we also assessed the mechanisms of mechanosignaling in the presence of an proinflammatory cytokine IL-1beta. In this article, we demonstrate that the mechanosignaling cascade is initiated by vascular endothelial growth receptor-2 (VEGFR2) activation. Mechanoactivation of VEGFR2 results in its nuclear translocation and elevation of PI3K-dependent Ser473-Akt phosphorylation. Subsequently, activated Akt inactivates the kinase activity of the serine/threonine kinase, glycogen synthase kinase-3beta (GSK3beta), via its Ser9 phosphorylation. Thus, inactive GSK3beta fails to phosphorylate cyclin D1 and prevents its proteosomal degradation and, consequently, promotes endothelial cell survival and proliferation. In the presence of IL-1beta, cyclin D1 is phosphorylated and degraded, leading to inhibition of cell proliferation. However, mechanical signals repress cyclin D1 phosphorylation and upregulate cell proliferation, despite the presence of IL-1beta. The data indicate that the VEGFR2/Akt/GSK3beta signaling cascade plays a critical role in sensing and phospho-relaying mechanical stimuli in endothelial cells. Furthermore, mechanical forces control highly interconnected networks of proinflammatory and Akt signaling cascades to upregulate endothelial cell proliferation.
Collapse
Affiliation(s)
- Jie Liu
- Biomechanics and Tissue Engineering Laboratory, Division of Oral Biology, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | | |
Collapse
|
34
|
Guo S, Colbert LS, Fuller M, Zhang Y, Gonzalez-Perez RR. Vascular endothelial growth factor receptor-2 in breast cancer. Biochim Biophys Acta Rev Cancer 2010; 1806:108-21. [PMID: 20462514 DOI: 10.1016/j.bbcan.2010.04.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 04/16/2010] [Accepted: 04/21/2010] [Indexed: 12/31/2022]
Abstract
Investigations over the last decade have established the essential role of growth factors and their receptors during angiogenesis and carcinogenesis. The vascular endothelial growth factor receptor (VEGFR) family in mammals contains three members, VEGFR-1 (Flt-1), VEGFR-2 (KDR/Flk-1) and VEGFR-3 (Flt-4), which are transmembrane tyrosine kinase receptors that regulate the formation of blood and lymphatic vessels. In the early 1990s, the above VEGFR was structurally characterized by cDNA cloning. Among these three receptors, VEGFR-2 is generally recognized to have a principal role in mediating VEGF-induced responses. VEGFR-2 is considered as the earliest marker for endothelial cell development. Importantly, VEGFR-2 directly regulates tumor angiogenesis. Therefore, several inhibitors of VEGFR-2 have been developed and many of them are now in clinical trials. In addition to targeting endothelial cells, the VEGF/VEGFR-2 system works as an essential autocrine/paracrine process for cancer cell proliferation and survival. Recent studies mark the continuous and increased interest in this related, but distinct, function of VEGF/VEGFR-2 in cancer cells: the autocrine/paracrine loop. Several mechanisms regulate VEGFR-2 levels and modulate its role in tumor angiogenesis and physiologic functions, i.e.: cellular localization/trafficking, regulation of cis-elements of promoter, epigenetic regulation and signaling from Notch, cytokines/growth factors and estrogen, etc. In this review, we will focus on updated information regarding VEGFR-2 research with respect to the molecular mechanisms of VEGFR-2 regulation in human breast cancer. Investigations in the activation, function, and regulation of VEGFR-2 in breast cancer will allow the development of new pharmacological strategies aimed at directly targeting cancer cell proliferation and survival.
Collapse
Affiliation(s)
- Shanchun Guo
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | | | | | | | | |
Collapse
|
35
|
Bruns AF, Herbert SP, Odell AF, Jopling HM, Hooper NM, Zachary IC, Walker JH, Ponnambalam S. Ligand-stimulated VEGFR2 signaling is regulated by co-ordinated trafficking and proteolysis. Traffic 2010; 11:161-74. [PMID: 19883397 DOI: 10.1111/j.1600-0854.2009.01001.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vascular endothelial growth factor A (VEGF-A)-induced signaling through VEGF receptor 2 (VEGFR2) regulates both physiological and pathological angiogenesis in mammals. However, the temporal and spatial mechanism underlying VEGFR2-mediated intracellular signaling is not clear. Here, we define a pathway for VEGFR2 trafficking and proteolysis that regulates VEGF-A-stimulated signaling and endothelial cell migration. Ligand-stimulated VEGFR2 activation and ubiquitination preceded proteolysis and cytoplasmic domain removal associated with endosomes. A soluble VEGFR2 cytoplasmic domain fragment displayed tyrosine phosphorylation and activation of downstream intracellular signaling. Perturbation of endocytosis by the depletion of either clathrin heavy chain or an ESCRT-0 subunit caused differential effects on ligand-stimulated VEGFR2 proteolysis and signaling. This novel VEGFR2 proteolysis was blocked by the inhibitors of 26S proteasome activity. Inhibition of proteasome activity prolonged VEGF-A-induced intracellular signaling to c-Akt and endothelial nitric oxide synthase (eNOS). VEGF-A-stimulated endothelial cell migration was dependent on VEGFR2 and VEGFR tyrosine kinase activity. Inhibition of proteasome activity in this assay stimulated VEGF-A-mediated endothelial cell migration. VEGFR2 endocytosis, ubiquitination and proteolysis could also be stimulated by a protein kinase C-dependent pathway. Thus, removal of the VEGFR2 carboxyl terminus linked to phosphorylation, ubiquitination and trafficking is necessary for VEGF-stimulated endothelial signaling and cell migration.
Collapse
Affiliation(s)
- Alexander F Bruns
- Endothelial Cell Biology Unit, Institute of Molecular and Cellular Biology, LIGHT Laboratories, University of Leeds, Leeds LS2 9JT, UK
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
The intracellular trafficking of receptors provides a way to control the overall sensitivity of a cell to receptor stimulation. These sorting pathways are also used to shape the balance of signals that are generated in response to receptor activation. The major pro-angiogenic growth factor receptor is VEGFR2 (vascular endothelial growth factor 2). VEGFR2 activates a very similar set of signalling pathways to other RTKs (receptor tyrosine kinases); however, its intracellular trafficking is very different. Furthermore, VEGFR2 can form a complex with a range of different angiogenic regulators that in turn regulate the trafficking of VEGFR2 through the endosomal pathway. This regulated trafficking of VEGFR2 has important consequences for angiogenic signalling and is a clear demonstration of how the endosomal pathway plays a critical role in connecting receptor signalling pathways to cellular events.
Collapse
|
37
|
Abstract
Regulation of angiogenesis is often viewed as a balance between pro-angiogenic and anti-angiogenic factors, and when the balance shifts in favour of angiogenesis stimulators, an angiogenic switch turns on the normally inactive endothelial cells to grow new blood vessels. Recent studies have shown that PLCγ1 (phospholipase Cγ1), a major signalling substrate of VEGFR-2 (vascular endothelial growth factor receptor 2), undergoes c-Cbl-mediated ubiquitination. c-Cbl suppresses tyrosine phosphorylation of PLCγ1 and with it VEGF (vascular endothelial growth factor)-induced endothelial cell proliferation and angiogenesis. Loss of c-Cbl in mice results in enhanced retinal neovascularization, VEGF- and tumour-induced angiogenesis. Notably, this observation suggests that c-Cbl-mediated ubiquitination pathway plays a central role in the ‘angiogenic switch’ employed by the VEGF system. The present article highlights the recent findings demonstrating a novel role for protein ubiquitination in angiogenesis and its potential in angiogenesis-based therapy.
Collapse
|
38
|
Tripathi R, Rath G, Ralhan R, Saxena S, Salhan S. Soluble and membranous vascular endothelial growth factor receptor-2 in pregnancies complicated by pre-eclampsia. Yonsei Med J 2009; 50:656-66. [PMID: 19881969 PMCID: PMC2768240 DOI: 10.3349/ymj.2009.50.5.656] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 09/02/2008] [Accepted: 12/08/2008] [Indexed: 12/27/2022] Open
Abstract
PURPOSE There is a paucity of information on the serum soluble vascular endothelial growth factor receptor-2 (sVEGFR-2) concentrations, membranous VEGFR-2 expression and the mechanism involved in their modulations during the clinical onset of pre-eclampsia. This cross-sectional study was conducted to evaluate the concentration of sVEGFR-2 in serum and to investigate the expression of membranous VEGFR-2 in placentae of pre-eclampsia group. MATERIALS AND METHODS The serum levels of sVEGFR-2 (n = 120) and the expression of membranous VEGFR-2 in placentae (n = 100) were analysed at third trimester of pregnancy by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry respectively. The diagnostic parameters of sensitivity, specificity and association of soluble and membranous VEGFR-2 in these patients were evaluated. RESULTS The serum levels of sVEGFR-2 in pre-eclampsia patients were found to be significantly reduced (p = 0.01, p = 0.001) in early and late pre-eclamptic sub-groups as compared to their respective third trimester control sub-groups. Also, the receiver operating characteristic (ROC) curve analysis showed a cut-off value of 7350.4 pg/mL, higher sensitivity (76%) and specificity (76%) for sVEGFR-2 in late onset (> 34 weeks) pre-eclamptic group. Significant down-regulation of membranous VEGFR-2 immunoreactivity was observed in all the placental cells (p = 0.0001) at > 34 weeks preeclamptic group. CONCLUSION The reduced serum levels of soluble VEGFR-2 and the down-regulated expression of membranous VEGFR-2 in the study group denoted abnormality in VEGF mediated placental function in all placental cells and thus VEGFR-2 may be a key factor, intimately associated with pre-eclampsia. This study shows the clinical utility of soluble and membranous VEGFR-2 in pre-eclampsia patients.
Collapse
Affiliation(s)
- Richa Tripathi
- Department of Anatomy, VMMC & Safdarjang Hospital, New Delhi, India.
| | | | | | | | | |
Collapse
|
39
|
An SJ, Chen ZH, Lin QX, Su J, Chen HJ, Lin JY, Wu YL. The -271 G>A polymorphism of kinase insert domain-containing receptor gene regulates its transcription level in patients with non-small cell lung cancer. BMC Cancer 2009; 9:144. [PMID: 19435508 PMCID: PMC2687458 DOI: 10.1186/1471-2407-9-144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 05/12/2009] [Indexed: 01/23/2023] Open
Abstract
Background Kinase insert domain-containing receptor (KDR) plays a critical role in the metastasis of cancer and is used as a molecular target in cancer therapy. We investigated the characteristics of the -271 G>A polymorphism of the KDR gene to gain information that may benefit the development of individualized therapies for patients with non-small cell lung cancer (NSCLC). Methods The -271 G>A polymorphism of the KDR gene in 106 lung cancer patients and 203 healthy control individuals was analyzed by polymerase chain reaction (PCR) and DNA sequencing methods. Real-time quantitative PCR and immunohistochemical methods were used to evaluate KDR mRNA and protein expression levels, respectively, in frozen tumor specimens. Results The -271 G>A polymorphism was associated with the mRNA expression level of the KDR gene in tumor tissues (t = 2.178, P = 0.032, independent samples t-test). Compared with the AG/GG genotype, the AA genotype was associated with higher KDR mRNA expression in tumor tissues. We found no relationship between the genotype and the KDR protein expression level and no significant difference in the distribution of the KDR gene polymorphism genotypes between lung cancer patients and the control group (χ2 = 1.269, P = 0.264, Fisher's exact test). Conclusion This study is the first to show that the -271 G>A polymorphism of the KDR gene may be a functional polymorphism related to the regulation of gene transcription. These findings may have important implications for therapies targeting KDR in patients with NSCLC.
Collapse
Affiliation(s)
- She-Juan An
- Medical Research Center of Guangdong General Hospital, Guangdong Lung Cancer Institute, Guangdong Academy of Medical Sciences, Guangzhou, PR China.
| | | | | | | | | | | | | |
Collapse
|
40
|
Rahimi N, Golde TE, Meyer RD. Identification of ligand-induced proteolytic cleavage and ectodomain shedding of VEGFR-1/FLT1 in leukemic cancer cells. Cancer Res 2009; 69:2607-14. [PMID: 19276374 DOI: 10.1158/0008-5472.can-08-2905] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular endothelial growth factor receptor-1/fms-related tyrosine kinase 1 (VEGFR-1/FLT1) is expressed as a membrane-bound receptor tyrosine kinase and as an alternatively spliced soluble protein (sVEGFR-1) containing the 1-6 IgG-like domain of its ectodomain. sVEGFR-1 is known as a naturally occurring inhibitor of angiogenesis and as a surrogate marker for cancer progression; it is also linked to pregnancy-induced hypertension called preeclampsia and to avascularity of normal cornea. It remains an open question whether alternative mRNA splicing is the only mechanism by which sVEGFR-1 is generated. In this study, we show that in leukemic cancer cells, PlGF and VEGF-A both induce tyrosine phosphorylation of VEGFR-1 and render it susceptible to ectodomain shedding, resulting in the generation of sVEGFR-1 and an intracellular cytoplasmic fragment. Activation of protein kinase C and tumor necrosis factor-alpha-converting enzyme family metalloproteases are critically required for the occurrence of sVEGFR-1. Following the removal of the ectodomain, the remnant of VEGFR-1 remains attached to the membrane, and the activity of gamma-secretase/presenilin is required for its release from the cell membrane. We propose that sVEGFR-1 produced via ectodomain shedding plays a prominent role in the VEGF receptor system by antagonizing VEGF receptor signaling by acting as a dominant-negative form and/or forming a nonsignaling dimerizing complex with VEGF receptors.
Collapse
Affiliation(s)
- Nader Rahimi
- Department of Pathology and Ophthalmology, Boston University Medical School, Boston, Massachusetts, USA.
| | | | | |
Collapse
|
41
|
Olszewska-Pazdrak B, Hein TW, Olszewska P, Carney DH. Chronic hypoxia attenuates VEGF signaling and angiogenic responses by downregulation of KDR in human endothelial cells. Am J Physiol Cell Physiol 2009; 296:C1162-70. [PMID: 19244479 DOI: 10.1152/ajpcell.00533.2008] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coronary artery disease results in progressive vascular stenosis associated with chronic myocardial ischemia. Vascular endothelial growth factor (VEGF) stimulates endothelial cell angiogenic responses to revascularize ischemic tissues; however, the effect of chronic hypoxia on the responsiveness of endothelial cells to VEGF remains unclear. We, therefore, investigated whether hypoxia alters VEGF-stimulated signaling and angiogenic responses in primary human coronary artery endothelial (HCAE) cells. Exposure of HCAE cells to hypoxia (1% O(2)) for 24 h decreased VEGF-stimulated endothelial cell migration ( approximately 82%), proliferation ( approximately 30%), and tube formation. Hypoxia attenuated VEGF-stimulated activation of endothelial nitric oxide (NO) synthase (eNOS) ( approximately 72%) and reduced NO production in VEGF-stimulated cells from 237 +/- 38.8 to 61.3 +/- 28.4 nmol/l. Moreover, hypoxia also decreased the ratio of phosphorylated eNOS to total eNOS in VEGF-stimulated cells by approximately 50%. This effect was not observed in thrombin-stimulated cells, suggesting that hypoxia specifically inhibited VEGF signaling upstream of eNOS phosphorylation. VEGF-induced activation of Akt, ERK1/2, p38, p70S6 kinases, and S6 ribosomal protein was also attenuated in hypoxic cells. Moreover, VEGF-stimulated phosphorylation of VEGF receptor-2 (KDR) at Y996 and Y1175 was decreased by hypoxia. This decrease correlated with a 70 +/- 12% decrease in KDR protein expression. Analysis of mRNA from these cells showed that hypoxia reduced steady-state levels of KDR mRNA by 52 +/- 16% and decreased mRNA stability relative to normoxic cells. Our findings demonstrate that chronic hypoxia attenuates VEGF-stimulated signaling in HCAE cells by specific downregulation of KDR expression. These data provide a novel explanation for the impaired angiogenic responses to VEGF in endothelial cells exposed to chronic hypoxia.
Collapse
Affiliation(s)
- Barbara Olszewska-Pazdrak
- Dept. of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555-0645, USA
| | | | | | | |
Collapse
|
42
|
Meyer RD, Sacks DB, Rahimi N. IQGAP1-dependent signaling pathway regulates endothelial cell proliferation and angiogenesis. PLoS One 2008; 3:e3848. [PMID: 19050761 PMCID: PMC2585478 DOI: 10.1371/journal.pone.0003848] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 11/10/2008] [Indexed: 12/03/2022] Open
Abstract
Background Vascular endothelial growth factor receptor-2 (VEGFR-2) signaling is an obligate requirement for normal development and pathological angiogenesis such as cancer and age-related macular degeneration. Although autophosphorylation of tyrosine 1173 (Y1173) of VEGFR-2 is considered a focal point for its angiogenic signal relay, however, the mechanism of phosphorylation of Y1173, signaling proteins that are recruited to this residue and their role in angiogenesis is not fully understood. Methodology/Principal Findings In this study we demonstrate that c-Src kinase directly through its Src homology 2 (SH2) domain and indirectly via c-Cbl binds to phospho-Y1057 of VEGFR-2. Activation of c-Src kinase by a positive feedback mechanism phosphorylates VEGFR-2 at multi-docking site, Y1173. c-Src also catalyzes tyrosine phosphorylation of IQGAP1 and acts as an adaptor to bridge IQGAP1 to VEGFR-2. In turn, IQGAP1 activates b-Raf and mediates proliferation of endothelial cells. Silencing expression of IQGAP1 and b-Raf revealed that their activity is essential for VEGF to stimulate angiogenesis in an in vivo angiogenesis model of chicken chorioallantoic membrane (CAM). Conclusions/Significance Angiogenesis contributes to the pathology of numerous human diseases ranging from cancer to age-related macular degeneration. Determining molecular mechanism of tyrosine phosphorylation of VEGFR-2 and identification of molecules that are relaying its angiogenic signaling may identify novel targets for therapeutic intervention against angiogenesis-associated diseases. Our study shows that recruitment and activation of c-Src by VEGFR-2 plays a pivotal role in relaying angiogenic signaling of VEGFR-2; it phosphorylates VEGFR-2 at Y1173, facilitates association and activation of IQGAP1 and other signaling proteins to VEGFR-2. IQGAP1-dependent signaling, in part, is critically required for endothelial cell proliferation, a key step in angiogenesis. Thus, Y1057 of VEGFR-2 serves to regulate VEGFR-2 function in a combinatorial manner by supporting both diversity of recruitment of angiogenic signaling proteins to VEGFR-2, and its ability to promote angiogenesis.
Collapse
Affiliation(s)
- Rosana D. Meyer
- Departments of Pathology and Ophthalmology, School of Medicine, Boston University, Boston, Massachusetts, United States of America
| | - David B. Sacks
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nader Rahimi
- Departments of Pathology and Ophthalmology, School of Medicine, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
43
|
Zhang H, He Y, Dai S, Xu Z, Luo Y, Wan T, Luo D, Jones D, Tang S, Chen H, Sessa WC, Min W. AIP1 functions as an endogenous inhibitor of VEGFR2-mediated signaling and inflammatory angiogenesis in mice. J Clin Invest 2008; 118:3904-16. [PMID: 19033661 DOI: 10.1172/jci36168] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 09/17/2008] [Indexed: 12/26/2022] Open
Abstract
ASK1-interacting protein-1 (AIP1), a recently identified member of the Ras GTPase-activating protein family, is highly expressed in vascular ECs and regulates EC apoptosis in vitro. However, its function in vivo has not been established. To study this, we generated AIP1-deficient mice (KO mice). Although these mice showed no obvious defects in vascular development, they exhibited dramatically enhanced angiogenesis in 2 models of inflammatory angiogenesis. In one of these models, the enhanced angiogenesis observed in the KO mice was associated with increased VEGF-VEGFR2 signaling. Consistent with this, VEGF-induced ear, cornea, and retina neovascularization were greatly augmented in KO mice and the enhanced retinal angiogenesis was markedly diminished by overexpression of AIP1. In vitro, VEGF-induced EC migration was inhibited by AIP1 overexpression, whereas it was augmented by both AIP1 knockout and knockdown, with the enhanced EC migration caused by AIP1 knockdown being associated with increased VEGFR2 signaling. We present mechanistic data that suggest AIP1 is recruited to the VEGFR2-PI3K complex, binding to both VEGFR2 and PI3K p85, at a late phase of the VEGF response, and that this leads to inhibition of VEGFR2 signaling. Taken together, our data demonstrate that AIP1 functions as an endogenous inhibitor in VEGFR2-mediated adaptive angiogenesis in mice.
Collapse
Affiliation(s)
- Haifeng Zhang
- Interdepartmental Program in Vascular Biology and Therapeutics, Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Wakusawa R, Abe T, Sato H, Yoshida M, Kunikata H, Sato Y, Nishida K. Expression of vasohibin, an antiangiogenic factor, in human choroidal neovascular membranes. Am J Ophthalmol 2008; 146:235-243. [PMID: 18486097 DOI: 10.1016/j.ajo.2008.03.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 03/10/2008] [Accepted: 03/13/2008] [Indexed: 12/14/2022]
Abstract
PURPOSE To determine whether vasohibin, an antiangiogenic factor produced by vascular endothelial cells, is expressed in the choroidal neovascular (CNV) membranes obtained from human eyes with age-related macular degeneration (AMD) or polypoidal choroidal vasculopathy (PCV). DESIGN Retrospective, interventional case series. METHODS The medical charts of 21 eyes of 21 patients with AMD or PCV who underwent surgical removal of the CNV membrane were reviewed. The removed tissues were immunostained for von Willebrand Factor (vWF), vascular endothelial growth factor (VEGF), and vasohibin. The levels of the messenger ribonucleic acid of VEGF, VEGFR2, and vasohibin were determined by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) from the CNV membranes excised from nine AMD and nine PCV patients. RESULTS The patients were divided into three groups; four patients were placed in the most active group (Group H), 13 in the less active group (Group E), and four in the nonactive group (Group S). Immunohistochemistry showed that vasohibin, vWF, and VEGF were expressed in the vascular endothelial cells in the CNV membranes and in the polypoidal vessels. RT-PCR showed that there was a strong correlation between the level of expression of VEGFR2 and vasohibin (P = .0002). Eyes with a lower vasohibin-to-VEGF ratio tended to have larger subretinal hemorrhages or vitreous hemorrhages, whereas eyes with higher vasohibin-to-VEGF ratio had subretinal fibrosislike lesions. Statistical analysis of the vasohibin-to-VEGF ratio among the three groups was significant (P = .0209). CONCLUSIONS Vasohibin is expressed in human CNV membranes. Our results indicate that the vasohibin-to-VEGF ratio may be related with the activity of the CNV.
Collapse
Affiliation(s)
- Ryosuke Wakusawa
- Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, Miyagi, Japan.
| | | | | | | | | | | | | |
Collapse
|
45
|
Asada M, Ebihara S, Numachi Y, Okazaki T, Yamanda S, Ikeda K, Yasuda H, Sora I, Arai H. Reduced tumor growth in a mouse model of schizophrenia, lacking the dopamine transporter. Int J Cancer 2008; 123:511-8. [PMID: 18470912 DOI: 10.1002/ijc.23562] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The incidence of cancer in patients with schizophrenia has been reported to be lower that in the general population. On the other hand, it is well established that patients with schizophrenia have a hyper-dopaminergic system and dopamine has the ability to inhibit tumor angiogenesis. Therefore, in order to investigate the molecular mechanisms responsible for the lower cancer risk in schizophrenic patients, we used a mouse model of schizophrenia, which shows hyper-dopaminergic transmission in the nerve terminals of dopaminergic neurons. Here, we hypothesized that tumor growth was reduced in a mouse model of schizophrenia, lacking the dopamine transporter (DAT), and investigated tumor growth and angiogenesis in DAT knockout mice. The subcutaneous tumor in mice inoculated with cancer cells was smaller in DAT-/- mice than in the wild type (p < 0.05); however, the level of plasma dopamine in DAT-/- mice was lower than that of control littermates. Using human umbilical vascular endothelial cells (HUVEC), we examined dopamine signaling through dopamine D(1) receptor (D(1)R) and D(2)R. Dopamine stimulation slightly decreased the surface expression of vascular endothelial growth factor receptor-2 (VEGF-R2) but induced the phosphorylation of VEGF-R2 through Src in HUVEC. In addition, DAT-/- mice had less D(1)R. Both pharmacological and genetic interruption of D(1)R showed inhibited tumor growth. These results suggest that modulation of the dopaminergic system may contribute to cancer therapy.
Collapse
Affiliation(s)
- Masanori Asada
- Department of Geriatrics and Gerontology, Tohoku University School of Medicine, Sendai, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Rask-Madsen C, King GL. Differential regulation of VEGF signaling by PKC-alpha and PKC-epsilon in endothelial cells. Arterioscler Thromb Vasc Biol 2008; 28:919-24. [PMID: 18323518 DOI: 10.1161/atvbaha.108.162842] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Vascular endothelial growth factor (VEGF) stimulates proangiogenic signal transduction and cell function in part through activation of protein kinase C (PKC). Our aim was to examine how individual isoforms of PKC affect VEGF action. METHODS AND RESULTS Transfection of bovine aortic endothelial cells with small interfering RNA (siRNA) targeting either PKC-alpha, delta, or epsilon caused a reduction in the cognate PKC protein by 76% to 89% without changing expression of nontargeted isoforms. Downregulation of PKC-epsilon abrogated VEGF-stimulated phosphorylation of Akt at Ser473 and eNOS at Ser1179 and decreased VEGF-stimulated NO synthase activity in intact cells. In contrast, PKC-alpha knockdown increased Akt and eNOS phosphorylation, whereas PKCdelta knockdown had no significant effect. PKC-epsilon knockdown also decreased VEGF-stimulated Erk1/2 phosphorylation and abolished VEGF-stimulated DNA synthesis. Consistent with an effect on several pathways of VEGF signaling, VEGF receptor-2 (VEGFR2) tyrosine phosphorylation and expression of VEGFR2 protein and mRNA was decreased by 81, 90, and 84%, respectively, during knockdown of PKC-epsilon, but increased during PKC-alpha knockdown. CONCLUSIONS By regulating VEGFR2 expression and activation, PKC-epsilon expression is critical for activation of Akt and eNOS by VEGF and contributes to VEGF-stimulated Erk activation, whereas PKC-alpha has opposite effects.
Collapse
Affiliation(s)
- Christian Rask-Madsen
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, Mass. 02215, USA
| | | |
Collapse
|
47
|
Ebos JML, Lee CR, Bogdanovic E, Alami J, Van Slyke P, Francia G, Xu P, Mutsaers AJ, Dumont DJ, Kerbel RS. Vascular endothelial growth factor-mediated decrease in plasma soluble vascular endothelial growth factor receptor-2 levels as a surrogate biomarker for tumor growth. Cancer Res 2008; 68:521-9. [PMID: 18199548 DOI: 10.1158/0008-5472.can-07-3217] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Vascular endothelial growth factor (VEGF) is a potent proangiogenic protein that activates VEGF receptor (VEGFR) tyrosine kinases expressed by vascular endothelial cells. We previously showed that one of these receptors, VEGFR-2, has a truncated soluble form (sVEGFR-2) that can be detected in mouse and human plasma. Because activation of VEGFR-2 plays an important role in tumor angiogenesis, clinical interest in monitoring plasma sVEGFR-2 levels in cancer patients has focused on its potential exploitation as a surrogate biomarker for disease progression as well as assessing efficacy/activity of antiangiogenic drugs, particularly those that target VEGF or VEGFR-2. However, no preclinical studies have been done to study sVEGFR-2 during tumor growth or the mechanisms involved in its modulation. Using spontaneously growing tumors and both localized and metastatic human tumor xenografts, we evaluated the relationship between sVEGFR-2 and tumor burden as well as underlying factors governing protein level modulation in vivo. Our results show an inverse relationship between the levels of sVEGFR-2 and tumor size. Furthermore, using various methods of VEGF overexpression in vivo, including cell transfection and adenoviral delivery, we found plasma sVEGFR-2 decreases to be mediated largely by tumor-derived VEGF. Finally, in vitro studies indicate VEGF-mediated sVEGFR-2 modulation is the result of ligand-induced down-regulation of the VEGFR-2 from the cell surface. Taken together, these findings may be pertinent to further clinical exploitation of plasma sVEGFR-2 levels as a surrogate biomarker of VEGF-dependent tumor growth as well as an activity indicator of antiangiogenic drugs that target the VEGFR system.
Collapse
Affiliation(s)
- John M L Ebos
- Sunnybrook Health Sciences Centre, Molecular and Cellular Biology Research, University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
VEGF Signal Tranduction in Angiogenesis. Angiogenesis 2008. [DOI: 10.1007/978-0-387-71518-6_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
49
|
Pouchain D, Díaz-Mochón JJ, Bialy L, Bradley M. A 10,000 member PNA-encoded peptide library for profiling tyrosine kinases. ACS Chem Biol 2007; 2:810-8. [PMID: 18154268 DOI: 10.1021/cb700199k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A 10,000 member peptide nucleic acid (PNA) encoded peptide library was prepared, treated with the Abelson tyrosine kinase (Abl), and decoded using a DNA microarray and a fluorescently labeled secondary antiphosphotyrosine antibody. A dual-color approach ensured internal referencing for each and every member of the library and the generation of robust data sets. Analysis identified 155 peptides (out of 10,000) that were strongly phosphorylated by Abl in full agreement with known Abl specificities. BLAST analysis identified known cellular Abl substrates such as c-Jun amino-terminal kinase as well as new potential target proteins such as the G-protein coupled receptor kinase 6 and diacylglycerol kinase gamma. To illustrate the generalization of this approach, two other tyrosine kinases, human epidermal growth factor 2 (Her2) and vascular endothelial growth factor receptor 2/kinase insert domain protein receptor (VEGFR2/KDR), were profiled allowing characterization of specific peptide sequences known to interact with these kinases; under these conditions Her2 was demonstrated to have a marked preference for D-proline perhaps offering a unique means of targeting and inhibiting this kinase.
Collapse
Affiliation(s)
- Delphine Pouchain
- EaStCHEM, School of Chemistry, University of Edinburgh,
Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Juan J. Díaz-Mochón
- EaStCHEM, School of Chemistry, University of Edinburgh,
Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Laurent Bialy
- EaStCHEM, School of Chemistry, University of Edinburgh,
Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Mark Bradley
- EaStCHEM, School of Chemistry, University of Edinburgh,
Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, U.K
| |
Collapse
|
50
|
Holmes K, Roberts OL, Thomas AM, Cross MJ. Vascular endothelial growth factor receptor-2: structure, function, intracellular signalling and therapeutic inhibition. Cell Signal 2007; 19:2003-12. [PMID: 17658244 DOI: 10.1016/j.cellsig.2007.05.013] [Citation(s) in RCA: 707] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 05/08/2007] [Indexed: 12/15/2022]
Abstract
Vascular endothelial growth factors (VEGFs) regulate vascular development, angiogenesis and lymphangiogenesis by binding to a number of receptors. VEGFR-1 is required for the recruitment of haematopoietic stem cells and the migration of monocytes and macrophages, VEGFR-2 regulates vascular endothelial function and VEGFR-3 regulates lymphatic endothelial cell function. Over the last decade, considerable progress has been made in delineating the VEGFR-2 specific intracellular signalling cascades leading to proliferation, migration, survival and increased permeability, each of which contributes to the angiogenic response. Furthermore, therapeutic inhibition of VEGFR-2 action is now having an impact in the clinic for the treatment of a number of diseases.
Collapse
Affiliation(s)
- Katherine Holmes
- North West Cancer Research Fund Institute, School of Biological Sciences, College of Natural Sciences, University of Wales, Bangor, UK
| | | | | | | |
Collapse
|