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Oliveira RHDM, Annex BH, Popel AS. Endothelial cells signaling and patterning under hypoxia: a mechanistic integrative computational model including the Notch-Dll4 pathway. Front Physiol 2024; 15:1351753. [PMID: 38455844 PMCID: PMC10917925 DOI: 10.3389/fphys.2024.1351753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Introduction: Several signaling pathways are activated during hypoxia to promote angiogenesis, leading to endothelial cell patterning, interaction, and downstream signaling. Understanding the mechanistic signaling differences between endothelial cells under normoxia and hypoxia and their response to different stimuli can guide therapies to modulate angiogenesis. We present a novel mechanistic model of interacting endothelial cells, including the main pathways involved in angiogenesis. Methods: We calibrate and fit the model parameters based on well-established modeling techniques that include structural and practical parameter identifiability, uncertainty quantification, and global sensitivity. Results: Our results indicate that the main pathways involved in patterning tip and stalk endothelial cells under hypoxia differ, and the time under hypoxia interferes with how different stimuli affect patterning. Additionally, our simulations indicate that Notch signaling might regulate vascular permeability and establish different Nitric Oxide release patterns for tip/stalk cells. Following simulations with various stimuli, our model suggests that factors such as time under hypoxia and oxygen availability must be considered for EC pattern control. Discussion: This project provides insights into the signaling and patterning of endothelial cells under various oxygen levels and stimulation by VEGFA and is our first integrative approach toward achieving EC control as a method for improving angiogenesis. Overall, our model provides a computational framework that can be built on to test angiogenesis-related therapies by modulation of different pathways, such as the Notch pathway.
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Affiliation(s)
| | - Brian H. Annex
- Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Aleksander S. Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
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Oliveira RHM, Annex BH, Popel AS. Endothelial cells signaling and patterning under hypoxia: a mechanistic integrative computational model including the Notch-Dll4 pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539270. [PMID: 37205581 PMCID: PMC10187169 DOI: 10.1101/2023.05.03.539270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Several signaling pathways are activated during hypoxia to promote angiogenesis, leading to endothelial cell patterning, interaction, and downstream signaling. Understanding the mechanistic signaling differences between normoxia and hypoxia can guide therapies to modulate angiogenesis. We present a novel mechanistic model of interacting endothelial cells, including the main pathways involved in angiogenesis. We calibrate and fit the model parameters based on well-established modeling techniques. Our results indicate that the main pathways involved in the patterning of tip and stalk endothelial cells under hypoxia differ, and the time under hypoxia affects how a reaction affects patterning. Interestingly, the interaction of receptors with Neuropilin1 is also relevant for cell patterning. Our simulations under different oxygen concentrations indicate time- and oxygen-availability-dependent responses for the two cells. Following simulations with various stimuli, our model suggests that factors such as period under hypoxia and oxygen availability must be considered for pattern control. This project provides insights into the signaling and patterning of endothelial cells under hypoxia, contributing to studies in the field.
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Affiliation(s)
- Rebeca Hannah M Oliveira
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205, USA
| | - Brian H Annex
- Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205, USA
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3
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Song M, Finley SD. Mechanistic characterization of endothelial sprouting mediated by pro-angiogenic signaling. Microcirculation 2021; 29:e12744. [PMID: 34890488 PMCID: PMC9285777 DOI: 10.1111/micc.12744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 11/04/2021] [Accepted: 12/01/2021] [Indexed: 11/30/2022]
Abstract
Objective We aim to quantitatively characterize the crosstalk between VEGF‐ and FGF‐mediated angiogenic signaling and endothelial sprouting, to gain mechanistic insights and identify novel therapeutic strategies. Methods We constructed an experimentally validated hybrid agent‐based mathematical model that characterizes endothelial sprouting driven by FGF‐ and VEGF‐mediated signaling. We predicted the total sprout length, number of sprouts, and average length by the mono‐ and co‐stimulation of FGF and VEGF. Results The experimentally fitted and validated model predicts that FGF induces stronger angiogenic responses in the long‐term compared with VEGF stimulation. Also, FGF plays a dominant role in the combination effects in endothelial sprouting. Moreover, the model suggests that ERK and Akt pathways and cellular responses contribute differently to the sprouting process. Last, the model predicts that the strategies to modulate endothelial sprouting are context‐dependent, and our model can identify potential effective pro‐ and anti‐angiogenic targets under different conditions and study their efficacy. Conclusions The model provides detailed mechanistic insight into VEGF and FGF interactions in sprouting angiogenesis. More broadly, this model can be utilized to identify targets that influence angiogenic signaling leading to endothelial sprouting and to study the effects of pro‐ and anti‐angiogenic therapies.
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Affiliation(s)
- Min Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA.,Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California, USA.,Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, California, USA
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4
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Ma C, Dou X, Yan J, Wang S, Yang R, Su F, Zhang H, Su X. Optimal Saturated Neuropilin-1 Expression in Normal Tissue Maximizes Tumor Exposure to Anti-Neuropilin-1 Monoclonal Antibody. Anticancer Agents Med Chem 2020; 19:2269-2275. [PMID: 31692439 DOI: 10.2174/1871520619666191105150235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 01/18/2023]
Abstract
BACKGROUND As involved in tumor angiogenesis, Neuropilin Receptor type-1 (NRP-1) serves as an attractive target for cancer molecular imaging and therapy. Widespread expression of NRP-1 in normal tissues may affect anti-NRP-1 antibody tumor uptake. OBJECTIVE To assess a novel anti-NRP-1 monoclonal antibody A6-11-26 biodistribution in NRP-1 positive tumor xenograft models to understand the relationships between dose, normal tissue uptake and tumor uptake. METHODS The A6-11-26 was radiolabeled with 131I and the mice bearing U87MG xenografts were then administered with 131I-labelled A6-11-26 along with 0, 2.5, 5, and 10mg·kg-1 unlabelled antibody A6-11-26. Biodistribution and SPECT/CT imaging were evaluated. RESULTS 131I-A6-11-26 was synthesized successfully by hybridoma within 60min. It showed that most of 131IA6- 11-26 were in the plasma and serum (98.5 ± 0.16 and 88.9 ± 5.84, respectively), whereas, less in blood cells. For in vivo biodistribution studies, after only injection of 131I-A6-11-26, high levels of radioactivity were observed in the liver, moderate level in lungs. However, liver and lungs radioactivity uptakes could be competitively blocked by an increasing amount of unlabeled antibody A6-11-26, which can increase tumor radioactivity levels, but not in a dose-dependent manner. A dose between 10 and 20mg·kg-1 of unlabeled antibody A6-11-26 may be the optimal dose that maximized tumor exposure. CONCLUSION Widespread expression of NRP-1 in normal tissue may affect the distribution of A6-11-26 to tumor tissue. An appropriate antibody A6-11-26 dose would be required to saturate normal tissue antigenic sinks to achieve acceptable tumor exposure.
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Affiliation(s)
- Chao Ma
- Department of Nuclear Medicine, Zhongshan Hospital Xiamen University, Xiamen 361004, China
| | - Xiaofeng Dou
- Department of Nuclear Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310052, China
| | - Jianghua Yan
- Cancer Research Center of Medical School, Xiamen University, Xiamen 361102, China
| | - Shengyu Wang
- Cancer Research Center of Medical School, Xiamen University, Xiamen 361102, China
| | - Rongshui Yang
- Department of Nuclear Medicine, Zhongshan Hospital Xiamen University, Xiamen 361004, China
| | - Fu Su
- Department of Nuclear Medicine, Zhongshan Hospital Xiamen University, Xiamen 361004, China
| | - Huijuan Zhang
- Department of Radiology, Jinshan Branch, Fujian Provincial Hospital of Fujian Medical University, Fuzhou 350001, China
| | - Xinhui Su
- Department of Nuclear Medicine, Zhongshan Hospital Xiamen University, Xiamen 361004, China
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5
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Song M, Finley SD. ERK and Akt exhibit distinct signaling responses following stimulation by pro-angiogenic factors. Cell Commun Signal 2020; 18:114. [PMID: 32680529 PMCID: PMC7368799 DOI: 10.1186/s12964-020-00595-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 05/11/2020] [Indexed: 02/07/2023] Open
Abstract
Background Angiogenesis plays an important role in the survival of tissues, as blood vessels provide oxygen and nutrients required by the resident cells. Thus, targeting angiogenesis is a prominent strategy in many different settings, including both tissue engineering and cancer treatment. However, not all of the approaches that modulate angiogenesis lead to successful outcomes. Angiogenesis-based therapies primarily target pro-angiogenic factors such as vascular endothelial growth factor-A (VEGF) or fibroblast growth factor (FGF) in isolation, and there is a limited understanding of how these promoters combine together to stimulate angiogenesis. Targeting one pathway could be insufficient, as alternative pathways may compensate, diminishing the overall effect of the treatment strategy. Methods To gain mechanistic insight and identify novel therapeutic strategies, we have developed a detailed mathematical model to quantitatively characterize the crosstalk of FGF and VEGF intracellular signaling. The model focuses on FGF- and VEGF-induced mitogen-activated protein kinase (MAPK) signaling to promote cell proliferation and the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway, which promotes cell survival and migration. We fit the model to published experimental datasets that measure phosphorylated extracellular regulated kinase (pERK) and Akt (pAkt) upon FGF or VEGF stimulation. We validate the model with separate sets of data. Results We apply the trained and validated mathematical model to characterize the dynamics of pERK and pAkt in response to the mono- and co-stimulation by FGF and VEGF. The model predicts that for certain ranges of ligand concentrations, the maximum pERK level is more responsive to changes in ligand concentration compared to the maximum pAkt level. Also, the combination of FGF and VEGF indicates a greater effect in increasing the maximum pERK compared to the summation of individual effects, which is not seen for maximum pAkt levels. In addition, our model identifies the influential species and kinetic parameters that specifically modulate the pERK and pAkt responses, which represent potential targets for angiogenesis-based therapies. Conclusions Overall, the model predicts the combination effects of FGF and VEGF stimulation on ERK and Akt quantitatively and provides a framework to mechanistically explain experimental results and guide experimental design. Thus, this model can be utilized to study the effects of pro- and anti-angiogenic therapies that particularly target ERK and/or Akt activation upon stimulation with FGF and VEGF. Video Abstract
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Affiliation(s)
- Min Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA. .,Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA. .,Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
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6
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Li D, Finley SD. Exploring the Extracellular Regulation of the Tumor Angiogenic Interaction Network Using a Systems Biology Model. Front Physiol 2019; 10:823. [PMID: 31379588 PMCID: PMC6656929 DOI: 10.3389/fphys.2019.00823] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/12/2019] [Indexed: 12/31/2022] Open
Abstract
Tumor angiogenesis is regulated by pro- and anti-angiogenic factors. Anti-angiogenic agents target the interconnected network of angiogenic factors to inhibit neovascularization, which subsequently impedes tumor growth. Due to the complexity of this network, optimizing anti-angiogenic cancer treatments requires detailed knowledge at a systems level. In this study, we constructed a tumor tissue-based model to better understand how the angiogenic network is regulated by opposing mediators at the extracellular level. We consider the network comprised of two pro-angiogenic factors: vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF2), and two anti-angiogenic factors: thrombospondin-1 (TSP1) and platelet factor 4 (PF4). The model's prediction of angiogenic factors' distribution in tumor tissue reveals the localization of different factors and indicates the angiogenic state of the tumor. We explored how the distributions are affected by the secretion of the pro- and anti-angiogenic factors, illustrating how the angiogenic network is regulated in the extracellular space. Interestingly, we identified a counterintuitive result that the secretion of the anti-angiogenic factor PF4 can enhance pro-angiogenic signaling by elevating the levels of the interstitial and surface-level pro-angiogenic species. This counterintuitive situation is pertinent to the clinical setting, such as the release of anti-angiogenic factors in platelet activation or the administration of exogenous PF4 for anti-angiogenic therapy. Our study provides mechanistic insights into this counterintuitive result and highlights the role of heparan sulfate proteoglycans in regulating the interactions between angiogenic factors. This work complements previous studies aimed at understanding the formation of angiogenic complexes in tumor tissue and helps in the development of anti-cancer strategies targeting angiogenesis.
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Affiliation(s)
- Ding Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Stacey D Finley
- Department of Biomedical Engineering, Mork Family Department of Chemical Engineering and Materials Science, and Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
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7
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Veith AP, Henderson K, Spencer A, Sligar AD, Baker AB. Therapeutic strategies for enhancing angiogenesis in wound healing. Adv Drug Deliv Rev 2019; 146:97-125. [PMID: 30267742 DOI: 10.1016/j.addr.2018.09.010] [Citation(s) in RCA: 415] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 09/15/2018] [Accepted: 09/24/2018] [Indexed: 12/19/2022]
Abstract
The enhancement of wound healing has been a goal of medical practitioners for thousands of years. The development of chronic, non-healing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. A key aspect of many non-healing wounds is the reduced presence of vessel growth through the process of angiogenesis. This review surveys the creation of new treatments for healing cutaneous wounds through therapeutic angiogenesis. In particular, we discuss the challenges and advancement that have been made in delivering biologic, pharmaceutical and cell-based therapies as enhancers of wound vascularity and healing.
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Li D, Finley SD. The impact of tumor receptor heterogeneity on the response to anti-angiogenic cancer treatment. Integr Biol (Camb) 2019; 10:253-269. [PMID: 29623971 DOI: 10.1039/c8ib00019k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Multiple promoters and inhibitors mediate angiogenesis, the formation of new blood vessels, and these factors represent potential targets for impeding vessel growth in tumors. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor targeted in anti-angiogenic cancer therapies. In addition, thrombospondin-1 (TSP1) is a major endogenous inhibitor of angiogenesis, and TSP1 mimetics are being developed as an alternative type of anti-angiogenic agent. The combination of bevacizumab, an anti-VEGF agent, and ABT-510, a TSP1 mimetic, has been tested in clinical trials to treat advanced solid tumors. However, the patients' responses are highly variable and show disappointing outcomes. To obtain mechanistic insight into the effects of this combination anti-angiogenic therapy, we have constructed a novel whole-body systems biology model including the VEGF and TSP1 reaction networks. Using this molecular-detailed model, we investigated how the combination anti-angiogenic therapy changes the amounts of pro-angiogenic and anti-angiogenic complexes in cancer patients. We particularly focus on answering the question of how the effect of the combination therapy is influenced by tumor receptor expression, one aspect of patient-to-patient variability. Overall, this model complements the clinical administration of combination anti-angiogenic therapy, highlights the role of tumor receptor variability in the heterogeneous responses to anti-angiogenic therapy, and identifies the tumor receptor profiles that correlate with a high likelihood of a positive response to the combination therapy. Our model provides novel understanding of the VEGF-TSP1 balance in cancer patients at the systems-level and could be further used to optimize combination anti-angiogenic therapy.
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Affiliation(s)
- Ding Li
- Department of Biomedical Engineering, University of Southern California, 1042 Downey Way, DRB 140, Los Angeles, California 90089, USA.
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9
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Kühn C, Checa S. Computational Modeling to Quantify the Contributions of VEGFR1, VEGFR2, and Lateral Inhibition in Sprouting Angiogenesis. Front Physiol 2019; 10:288. [PMID: 30971939 PMCID: PMC6445957 DOI: 10.3389/fphys.2019.00288] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 03/05/2019] [Indexed: 12/25/2022] Open
Abstract
Sprouting angiogenesis is a necessary process in regeneration and development as well as in tumorigenesis. VEGF-A is the main pro-angiogenic chemoattractant and it can bind to the decoy receptor VEGFR1 or to VEGFR2 to induce sprouting. Active sprout cells express Dll4, which binds to Notch1 on neighboring cells, in turn inhibiting VEGFR2 expression. It is known that the balance between VEGFR2 and VEGFR1 determines tip selection and network architecture, however the quantitative interrelationship of the receptors and their interrelated balances, also with relation to Dll4-Notch1 signaling, remains yet largely unknown. Here, we present an agent-based computer model of sprouting angiogenesis, integrating VEGFR1 and VEGFR2 in a detailed model of cellular signaling. Our model reproduces experimental data on VEGFR1 knockout. We show that soluble VEGFR1 improves the efficiency of angiogenesis by directing sprouts away from existing cells over a wide range of parameters. Our analysis unravels the relevance of the stability of the active notch intracellular domain as a dominating hub in this regulatory network. Our analysis quantitatively dissects the regulatory interactions in sprouting angiogenesis. Because we use a detailed model of intracellular signaling, the results of our analysis are directly linked to biological entities. We provide our computational model and simulation engine for integration in complementary modeling approaches.
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Affiliation(s)
- Clemens Kühn
- Julius Wolff Institute, Charite - Universitätsmedizin Berlin, Berlin, Germany
| | - Sara Checa
- Julius Wolff Institute, Charite - Universitätsmedizin Berlin, Berlin, Germany.,Berlin-Brandenburg School for Regenerative Therapies, Charite - UIniversitätsmedizin Berlin, Berlin, Germany
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10
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Lam I, Pickering CM, Mac Gabhann F. Context-dependent regulation of receptor tyrosine kinases: Insights from systems biology approaches. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1437. [PMID: 30255986 PMCID: PMC6537588 DOI: 10.1002/wsbm.1437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 06/07/2018] [Accepted: 08/08/2018] [Indexed: 12/14/2022]
Abstract
Receptor tyrosine kinases (RTKs) are cell membrane proteins that provide cells with the ability to sense proteins in their environments. Many RTKs are essential to development and organ growth. Derangement of RTKs-by mutation or by overexpression-is central to several developmental and adult disorders including cancer, short stature, and vascular pathologies. The mechanism of action of RTKs is complex and is regulated by contextual components, including the existence of multiple competing ligands and receptors in many families, the intracellular location of the RTK, the dynamic and cell-specific coexpression of other RTKs, and the commonality of downstream signaling pathways. This means that both the state of the cell and the microenvironment outside the cell play a role, which makes sense given the pivotal location of RTKs as the nexus linking the extracellular milieu to intracellular signaling and modification of cell behavior. In this review, we describe these different contextual components through the lens of systems biology, in which both computational modeling and experimental "omics" approaches have been used to better understand RTK networks. The complexity of these networks is such that using these systems biology approaches is necessary to get a handle on the mechanisms of pathology and the design of therapeutics targeting RTKs. In particular, we describe in detail three concrete examples (involving ErbB3, VEGFR2, and AXL) that illustrate how systems approaches can reveal key mechanistic and therapeutic insights. This article is categorized under: Biological Mechanisms > Cell Signaling Models of Systems Properties and Processes > Mechanistic Models Translational, Genomic, and Systems Medicine > Therapeutic Methods.
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Affiliation(s)
- Inez Lam
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Christina M Pickering
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland
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11
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Song M, Finley SD. Mechanistic insight into activation of MAPK signaling by pro-angiogenic factors. BMC SYSTEMS BIOLOGY 2018; 12:145. [PMID: 30591051 PMCID: PMC6307205 DOI: 10.1186/s12918-018-0668-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/30/2018] [Indexed: 01/14/2023]
Abstract
Background Angiogenesis is important in physiological and pathological conditions, as blood vessels provide nutrients and oxygen needed for tissue growth and survival. Therefore, targeting angiogenesis is a prominent strategy in both tissue engineering and cancer treatment. However, not all of the approaches to promote or inhibit angiogenesis lead to successful outcomes. Angiogenesis-based therapies primarily target pro-angiogenic factors such as vascular endothelial growth factor-A (VEGF) or fibroblast growth factor (FGF) in isolation. However, pre-clinical and clinical evidence shows these therapies often have limited effects. To improve therapeutic strategies, including targeting FGF and VEGF in combination, we need a quantitative understanding of the how the promoters combine to stimulate angiogenesis. Results In this study, we trained and validated a detailed mathematical model to quantitatively characterize the crosstalk of FGF and VEGF intracellular signaling. This signaling is initiated by FGF binding to the FGF receptor 1 (FGFR1) and heparan sulfate glycosaminoglycans (HSGAGs) or VEGF binding to VEGF receptor 2 (VEGFR2) to promote downstream signaling. The model focuses on FGF- and VEGF-induced mitogen-activated protein kinase (MAPK) signaling and phosphorylation of extracellular regulated kinase (ERK), which promotes cell proliferation. We apply the model to predict the dynamics of phosphorylated ERK (pERK) in response to the stimulation by FGF and VEGF individually and in combination. The model predicts that FGF and VEGF have differential effects on pERK. Additionally, since VEGFR2 upregulation has been observed in pathological conditions, we apply the model to investigate the effects of VEGFR2 density and trafficking parameters. The model predictions show that these parameters significantly influence the response to VEGF stimulation. Conclusions The model agrees with experimental data and is a framework to synthesize and quantitatively explain experimental studies. Ultimately, the model provides mechanistic insight into FGF and VEGF interactions needed to identify potential targets for pro- or anti-angiogenic therapies. Electronic supplementary material The online version of this article (10.1186/s12918-018-0668-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Min Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA. .,Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California, USA. .,Department of Biological Sciences, Computational Biology section, University of Southern California, 1042 Downey Way, CRB 140, Los Angeles, CA, 90089, USA.
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12
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Ayanlaja AA, Zhang B, Ji G, Gao Y, Wang J, Kanwore K, Gao D. The reversible effects of glial cell line-derived neurotrophic factor (GDNF) in the human brain. Semin Cancer Biol 2018; 53:212-222. [PMID: 30059726 DOI: 10.1016/j.semcancer.2018.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/10/2018] [Accepted: 07/18/2018] [Indexed: 12/20/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor, and a member of the transforming growth factor β (TGF-β) superfamily acting on different neuronal activities. GDNF was originally identified as a neurotrophic factor crucially involved in the survival of dopaminergic neurons of the nigrostriatal pathway and is currently an established therapeutic target in Parkinson's disease. However, GDNF was later reported to be highly expressed in gliomas, especially in glioblastomas, and was demonstrated as a potent proliferation factor involved in the development and migration of gliomas. Here, we review our current understanding and progress made so far by researchers in our laboratories with references to relevant articles to support our discoveries. We present past and recent discoveries on the mechanisms involved in the protection of neurons by GDNF and examine its emerging roles in gliomas, as well as reasons for the abnormal expression in Glioblastoma Multiforme (GBM). Collectively, our work establishes a paradigm by which the ability of GDNF to protect dopaminergic neurons from degradation and its corresponding effects on glioma cells points to an underlying biological vulnerability in the effects of GDNF in the normal brain which can be subverted for use by cancer cells. Hence, presenting novel opportunities for intervention in glioma therapies.
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Affiliation(s)
- Abiola Abdulrahman Ayanlaja
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Baole Zhang
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - GuangQuan Ji
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Yue Gao
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Jie Wang
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Kouminin Kanwore
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - DianShuai Gao
- Xuzhou Key Laboratory of Neurobiology, Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China.
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Sun S, Lei Y, Li Q, Wu Y, Zhang L, Mu PP, Ji GQ, Tang CX, Wang YQ, Gao J, Gao J, Li L, Zhuo L, Li YQ, Gao DS. Neuropilin-1 is a glial cell line-derived neurotrophic factor receptor in glioblastoma. Oncotarget 2017; 8:74019-74035. [PMID: 29088765 PMCID: PMC5650320 DOI: 10.18632/oncotarget.18630] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/12/2017] [Indexed: 01/13/2023] Open
Abstract
The aim of this study was to identify the receptor for glial cell line-derived neurotrophic factor (GDNF) in glioblastoma multiforme (GBM). After GST pull-down assays, membrane proteins purified from C6 rat glioma cells were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The differentially expressed proteins were annotated using Gene Ontology, and neuropilin-1 (NRP1) was identified as the putative GDNF receptor in glioma. NRP1 was more highly expressed in human GBM brains and C6 rat glioma cells than in normal human brains or primary rat astrocytes. Immunofluorescence staining showed that NRP1 was recruited to the membrane by GDNF, and NRP1 co-immunoprecipitated with GDNF. Using the NRP1 and GDNF protein structures to assess molecular docking in the ZDOCK server and visualization with the PyMOL Molecular Graphics System revealed 8 H-bonds and stable positive and negative electrostatic interactions between NRP1 and GDNF. RNAi knockdown of NRP1 reduced proliferation of C6 glioma cells when stimulated with GDNF. NRP1 was an independent risk factor for both survival and recurrence in GBM patients. High NRP1 mRNA expression correlated with shorter OS and DFS (OS: χ2=4.6720, P=0.0307; DFS: χ2=11.013, P=0.0009). NRP1 is thus a GDNF receptor in glioma cells and a potential therapeutic target.
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Affiliation(s)
- Shen Sun
- Department of Anatomy and Histology, The Fourth Military Medical University, Xi'an, Shanxi, China.,Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China.,Department of Histology and Embryology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yu Lei
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China.,Department of Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Qi Li
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yue Wu
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Lin Zhang
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Pei-Pei Mu
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Guang-Quan Ji
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Chuan-Xi Tang
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yu-Qian Wang
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jian Gao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jin Gao
- Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Li Li
- Department of Pathophysiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Lang Zhuo
- Department of Epidemiology, School of Public Health, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Yun-Qing Li
- Department of Anatomy and Histology, The Fourth Military Medical University, Xi'an, Shanxi, China
| | - Dian-Shuai Gao
- Department of Anatomy and Histology, The Fourth Military Medical University, Xi'an, Shanxi, China.,Department of Neurobiology and Anatomy, Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu, China
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14
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Chu LH, Ganta VC, Choi MH, Chen G, Finley SD, Annex BH, Popel AS. A multiscale computational model predicts distribution of anti-angiogenic isoform VEGF 165b in peripheral arterial disease in human and mouse. Sci Rep 2016; 6:37030. [PMID: 27853189 PMCID: PMC5113071 DOI: 10.1038/srep37030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 10/24/2016] [Indexed: 12/11/2022] Open
Abstract
Angiogenesis is the growth of new blood vessels from pre-existing microvessels. Peripheral arterial disease (PAD) is caused by atherosclerosis that results in ischemia mostly in the lower extremities. Clinical trials including VEGF-A administration for therapeutic angiogenesis have not been successful. The existence of anti-angiogenic isoform (VEGF165b) in PAD muscle tissues is a potential cause for the failure of therapeutic angiogenesis. Experimental measurements show that in PAD human muscle biopsies the VEGF165b isoform is at least as abundant if not greater than the VEGF165a isoform. We constructed three-compartment models describing VEGF isoforms and receptors, in human and mouse, to make predictions on the secretion rate of VEGF165b and the distribution of various isoforms throughout the body based on the experimental data. The computational results are consistent with the data showing that in PAD calf muscles secrete mostly VEGF165b over total VEGF. In the PAD calf compartment of human and mouse models, most VEGF165a and VEGF165b are bound to the extracellular matrix. VEGF receptors VEGFR1, VEGFR2 and Neuropilin-1 (NRP1) are mostly in ‘Free State’. This study provides a computational model of VEGF165b in PAD supported by experimental measurements of VEGF165b in human and mouse, which gives insight of VEGF165b in therapeutic angiogenesis and VEGF distribution in human and mouse PAD model.
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Affiliation(s)
- Liang-Hui Chu
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Vijay Chaitanya Ganta
- Cardiovascular Medicine, Department of Medicine, and the Robert M. Berne Cardiovascular Research Center University of Virginia School of Medicine, Charlottesville, VA 22901, United States
| | - Min H Choi
- Cardiovascular Medicine, Department of Medicine, and the Robert M. Berne Cardiovascular Research Center University of Virginia School of Medicine, Charlottesville, VA 22901, United States
| | - George Chen
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Brian H Annex
- Cardiovascular Medicine, Department of Medicine, and the Robert M. Berne Cardiovascular Research Center University of Virginia School of Medicine, Charlottesville, VA 22901, United States
| | - Aleksander S Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, United States
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15
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Wang S, Gao X, Shen G, Wang W, Li J, Zhao J, Wei YQ, Edwards CK. Interleukin-10 deficiency impairs regulatory T cell-derived neuropilin-1 functions and promotes Th1 and Th17 immunity. Sci Rep 2016; 6:24249. [PMID: 27075020 PMCID: PMC4831052 DOI: 10.1038/srep24249] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 03/18/2016] [Indexed: 02/05/2023] Open
Abstract
Regulatory T cells (Tregs) expand in peripheral lymphoid organs and can produce immunosuppressive cytokines to support tumor growth. IL-10 abrogation efficiently induces Treg formation but dampens tumoral neuropilin-1 (Nrp-1) Treg signaling, which simultaneously augments Th1 and Th17 immunity. These effects are associated with the plasticity and stability of Tregs and effector T cell functions that can limit tumorigenesis. Within the tumor microenvironment, there appears to be a “mutual antagonism” between immunoenhancement and immunosuppression mechanisms, eventually leading to decreased metastasis. In contrast, tumor progression is paralleled by a reduction in Nrp-1-producing Tregs controlled by the IL-10 and TGF-β1 levels. However, Th1, Th17 and Treg immunity is primarily regulated by IL-10 or Nrp-1 and not TGF-β1 except when combined with IL-10. These results emphasize the important implications for the therapeutic use of Tregs. The number of Treg cells must be maintained in a healthy and dynamic homeostatic range to prevent malignant diseases. Moreover, Treg-mediated immunosuppression can be limited by reducing tumor-derived Treg Nrp-1 levels.
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Affiliation(s)
- Shimin Wang
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Xiang Gao
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China.,Institute of Neurosurgery, West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Guobo Shen
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Wei Wang
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Jingyu Li
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Jingyi Zhao
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Yu-Quan Wei
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
| | - Carl K Edwards
- Department of Neurosurgery, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, and West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, PR China
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16
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Li X, Parker MW, Vander Kooi CW. Control of cellular motility by neuropilin-mediated physical interactions. Biomol Concepts 2015; 5:157-66. [PMID: 25018786 DOI: 10.1515/bmc-2013-0035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The neuropilin (Nrp) family consists of multifunctional cell surface receptors with critical roles in a number of different cell and tissue types. A core aspect of Nrp function is in ligand-dependent cellular migration, where it controls the multistep process of cellular motility through integration of ligand binding and receptor signaling. At a molecular level, the role of Nrp in migration is intimately connected to the control of adhesive interactions and cytoskeletal reorganization. Here, we review the physiological role of Nrp in cellular adhesion and motility in the cardiovascular and nervous systems. We also discuss the emerging pathological role of Nrp in tumor cell migration and metastasis, providing motivation for continued efforts toward developing Nrp inhibitors.
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17
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Bender RJ, Mac Gabhann F. Dysregulation of the vascular endothelial growth factor and semaphorin ligand-receptor families in prostate cancer metastasis. BMC SYSTEMS BIOLOGY 2015; 9:55. [PMID: 26341082 PMCID: PMC4559909 DOI: 10.1186/s12918-015-0201-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 08/20/2015] [Indexed: 01/01/2023]
Abstract
Background The vascular endothelial growth factor (VEGF) family is central to cancer angiogenesis. However, targeting VEGF as an anti-cancer therapeutic approach has shown success for some tumor types but not others. Here we examine the expression of the expanded VEGF family in prostate cancer, including the Semaphorin (Sema) family members that compete with VEGFs for Neuropilin binding and can themselves have pro- or anti-angiogenic activity. Results First, we used multivariate statistical methods, including partial least squares and clustering, to examine VEGF/Sema gene expression variability in previously published prostate cancer microarray datasets. We show that unlike some cancers, such as kidney cancer, primary prostate cancer is characterized by both a down-regulation of the pro-angiogenic members of the VEGF family and a down-regulation of anti-angiogenic members of the Sema family. We found pro-lymphangiogenic signatures, including the genes encoding VEGFC and VEGFD, associated with primary tumors that ultimately became aggressive. In contrast to primary prostate tumors, prostate cancer metastases showed increased expression of key pro-angiogenic VEGF family members and further repression of anti-angiogenic class III Sema family members. Given the lack of success of VEGF-targeting molecules so far in prostate cancer, this suggests that the reduction in anti-angiogenic Sema signaling may potentiate VEGF signaling and even promote resistance to VEGF-targeting therapies. Inhibition of the VEGF ‘accelerator’ may need to be accompanied by promotion of the Sema ‘brake’ to block cancer angiogenesis. To leverage our mechanistic understanding, and to link multigene expression changes to outcomes, we performed individualized computational simulations of competitive VEGF and Sema receptor binding across many tumor samples. The simulations suggest that loss of Sema expression promotes angiogenesis by lowering plexin signaling, not by potentiating VEGF signaling via relaxation of competition. Conclusions The combined analysis of bioinformatic data with computational modeling of ligand-receptor interactions demonstrated that enhancement of angiogenesis in prostate cancer metastases may occur through two different routes: elevation of VEGFA and reduction of class 3 Semaphorins. Therapeutic inhibition of angiogenesis in metastatic prostate cancer should account for both of these routes. Electronic supplementary material The online version of this article (doi:10.1186/s12918-015-0201-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- R Joseph Bender
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA. .,Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, 21218, USA.
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA. .,Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, 21218, USA.
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18
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Clegg LE, Mac Gabhann F. Molecular mechanism matters: Benefits of mechanistic computational models for drug development. Pharmacol Res 2015; 99:149-54. [PMID: 26093283 DOI: 10.1016/j.phrs.2015.06.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/06/2015] [Indexed: 12/19/2022]
Abstract
Making drug development a more efficient and cost-effective process will have a transformative effect on human health. A key, yet underutilized, tool to aid in this transformation is mechanistic computational modeling. By incorporating decades of hard-won prior knowledge of molecular interactions, cellular signaling, and cellular behavior, mechanistic models can achieve a level of predictiveness that is not feasible using solely empirical characterization of drug pharmacodynamics. These models can integrate diverse types of data from cell culture and animal experiments, including high-throughput systems biology experiments, and translate the results into the context of human disease. This provides a framework for identification of new drug targets, measurable biomarkers for drug action in target tissues, and patient populations for which a drug is likely to be effective or ineffective. Additionally, mechanistic models are valuable in virtual screening of new therapeutic strategies, such as gene or cell therapy and tissue regeneration, identifying the key requirements for these approaches to succeed in a heterogeneous patient population. These capabilities, which are distinct from and complementary to those of existing drug development strategies, demonstrate the opportunity to improve success rates in the drug development pipeline through the use of mechanistic computational models.
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Affiliation(s)
- Lindsay E Clegg
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States.
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, United States
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19
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Clegg LW, Mac Gabhann F. Site-Specific Phosphorylation of VEGFR2 Is Mediated by Receptor Trafficking: Insights from a Computational Model. PLoS Comput Biol 2015; 11:e1004158. [PMID: 26067165 PMCID: PMC4466579 DOI: 10.1371/journal.pcbi.1004158] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/25/2015] [Indexed: 02/05/2023] Open
Abstract
Matrix-binding isoforms and non-matrix-binding isoforms of vascular endothelial growth factor (VEGF) are both capable of stimulating vascular remodeling, but the resulting blood vessel networks are structurally and functionally different. Here, we develop and validate a computational model of the binding of soluble and immobilized ligands to VEGF receptor 2 (VEGFR2), the endosomal trafficking of VEGFR2, and site-specific VEGFR2 tyrosine phosphorylation to study differences in induced signaling between these VEGF isoforms. In capturing essential features of VEGFR2 signaling and trafficking, our model suggests that VEGFR2 trafficking parameters are largely consistent across multiple endothelial cell lines. Simulations demonstrate distinct localization of VEGFR2 phosphorylated on Y1175 and Y1214. This is the first model to clearly show that differences in site-specific VEGFR2 activation when stimulated with immobilized VEGF compared to soluble VEGF can be accounted for by altered trafficking of VEGFR2 without an intrinsic difference in receptor activation. The model predicts that Neuropilin-1 can induce differences in the surface-to-internal distribution of VEGFR2. Simulations also show that ligated VEGFR2 and phosphorylated VEGFR2 levels diverge over time following stimulation. Using this model, we identify multiple key levers that alter how VEGF binding to VEGFR2 results in different coordinated patterns of multiple downstream signaling pathways. Specifically, simulations predict that VEGF immobilization, interactions with Neuropilin-1, perturbations of VEGFR2 trafficking, and changes in expression or activity of phosphatases acting on VEGFR2 all affect the magnitude, duration, and relative strength of VEGFR2 phosphorylation on tyrosines 1175 and 1214, and they do so predictably within our single consistent model framework. Vascular endothelial growth factor (VEGF) is an important regulator of blood vessel growth. To date, therapies attempting to harness the VEGF system to promote blood vessel growth (e.g. for wound healing or ischemic disease) have achieved only limited success. To improve VEGF-based therapies, we need to better understand how VEGF promotes development of functional blood vessels. We have developed a computational model of VEGF binding to the receptor VEGFR2, trafficking of VEGFR2 through endosomal compartments in the cell, and activation of VEGFR2 on several tyrosine residues. The pattern of tyrosines activated on VEGFR2 influences cell behavior, promoting cell survival, proliferation, or migration. The combination of these cues influences the diameter of vessels, degree of branching, and leakiness of the resultant vessel network. Our model shows that changes in VEGFR2 trafficking as a result of VEGF immobilization to the extracellular matrix are sufficient to describe observed changes in the pattern of VEGFR2 activation compared to stimulation with purely soluble VEGF. This model can be used to predict how VEGF immobilization, interactions with co-receptors or proteins that deactivate VEGFR2, and changes to VEGFR2 trafficking can be tuned to promote development of functional blood vessel networks for tissue engineering applications.
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Affiliation(s)
- Lindsay Wendel Clegg
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
| | - Feilim Mac Gabhann
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
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20
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Abstract
The vascular network carries blood throughout the body, delivering oxygen to tissues and providing a pathway for communication between distant organs. The network is hierarchical and structured, but also dynamic, especially at the smaller scales. Remodeling of the microvasculature occurs in response to local changes in oxygen, gene expression, cell-cell communication, and chemical and mechanical stimuli from the microenvironment. These local changes occur as a result of physiological processes such as growth and exercise, as well as acute and chronic diseases including stroke, cancer, and diabetes, and pharmacological intervention. While the vasculature is an important therapeutic target in many diseases, drugs designed to inhibit vascular growth have achieved only limited success, and no drug has yet been approved to promote therapeutic vascular remodeling. This highlights the challenges involved in identifying appropriate therapeutic targets in a system as complex as the vasculature. Systems biology approaches provide a means to bridge current understanding of the vascular system, from detailed signaling dynamics measured in vitro and pre-clinical animal models of vascular disease, to a more complete picture of vascular regulation in vivo. This will translate to an improved ability to identify multi-component biomarkers for diagnosis, prognosis, and monitoring of therapy that are easy to measure in vivo, as well as better drug targets for specific disease states. In this review, we summarize systems biology approaches that have advanced our understanding of vascular function and dysfunction in vivo, with a focus on computational modeling.
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Affiliation(s)
- Lindsay E Clegg
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
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21
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Guidolin D, Fede C, Albertin G, De Caro R. Investigating in vitro angiogenesis by computer-assisted image analysis and computational simulation. Methods Mol Biol 2015; 1214:197-214. [PMID: 25468606 DOI: 10.1007/978-1-4939-1462-3_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In vitro assays that stimulate the formation of capillary-like structures by EC have become increasingly popular, because they allow the study of the EC's intrinsic ability to self-organize to form vascular-like patterns. Here we describe a widely applied protocol involving the use of basement membrane matrix (Matrigel) as a suitable environment to induce an angiogenic phenotype in cultured EC. EC differentiation on basement membrane matrix is a highly specific process, which recapitulates many steps in blood vessel formation and for this reason it is presently considered as a reliable in vitro tool to identify factors with potential antiangiogenic or pro-angiogenic properties. The morphological features of the obtained cell patterns can also be accurately quantified by computer-assisted image analysis and the main steps of such a procedure will be here outlined and discussed. The dynamics of in vitro EC self-organization is a complex biological process, involving a network of interactions between a high number of cells. For this reason, the combined use of in vitro experiments and computational modeling can represent a key approach to unravel how mechanical and chemical signaling by EC coordinates their organization into capillary-like tubes. Thus, a particularly helpful approach to modeling is also briefly described together with examples of its application.
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Affiliation(s)
- Diego Guidolin
- Department of Molecular Medicine, Section of Anatomy, University of Padova, via Gabelli 65, 35121, Padova, Italy,
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22
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Finley SD, Chu LH, Popel AS. Computational systems biology approaches to anti-angiogenic cancer therapeutics. Drug Discov Today 2014; 20:187-97. [PMID: 25286370 DOI: 10.1016/j.drudis.2014.09.026] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/05/2014] [Accepted: 09/29/2014] [Indexed: 01/06/2023]
Abstract
Angiogenesis is an exquisitely regulated process that is required for physiological processes and is also important in numerous diseases. Tumors utilize angiogenesis to generate the vascular network needed to supply the cancer cells with nutrients and oxygen, and many cancer drugs aim to inhibit tumor angiogenesis. Anti-angiogenic therapy involves inhibiting multiple cell types, molecular targets, and intracellular signaling pathways. Computational tools are useful in guiding treatment strategies, predicting the response to treatment, and identifying new targets of interest. Here, we describe progress that has been made in applying mathematical modeling and bioinformatics approaches to study anti-angiogenic therapeutics in cancer.
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Affiliation(s)
- Stacey D Finley
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
| | - Liang-Hui Chu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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23
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Chaudhary B, Khaled YS, Ammori BJ, Elkord E. Neuropilin 1: function and therapeutic potential in cancer. Cancer Immunol Immunother 2014; 63:81-99. [PMID: 24263240 PMCID: PMC11028473 DOI: 10.1007/s00262-013-1500-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 11/10/2013] [Indexed: 12/15/2022]
Abstract
Neuropilin 1 (NRP1) is a transmembrane glycoprotein that acts as a co-receptor for a number of extracellular ligands including class III/IV semaphorins, certain isoforms of vascular endothelial growth factor and transforming growth factor beta. An exact understanding of the role of NRP1 in the immune system has been obscured by the differences in NRP1 expression observed between mice and humans. In mice, NRP1 is selectively expressed on thymic-derived Tregs and greatly enhances immunosuppressive function. In humans, NRP1 is expressed on plasmacytoid dendritic cells (pDCs) where it aids in priming immune responses and on a subset of T regulatory cells (Tregs) isolated from secondary lymph nodes. Preliminary studies that show NRP1 expression on T cells confers enhanced immunosuppressive activity. However, the mechanism by which this activity is mediated remains unclear. NRP1 expression has also been identified on activated T cells and Tregs isolated from inflammatory microenvironments, suggesting NRP1 might represent a novel T cell activation marker. Of clinical interest, NRP1 may enhance Treg tumour infiltration and a decrease in NRP1+ Tregs correlates with successful chemotherapy, suggesting a specific role for NRP1 in cancer pathology. As a therapeutic target, NRP1 allows simultaneous targeting of NRP1-expressing tumour vasculature, NRP1+ Tregs and pDCs. With the development of anti-NRP1 monoclonal antibodies and cell-penetrating peptides, NRP1 represents a promising new target for cancer therapies. This paper reviews current knowledge on the role and function of NRP1 in Tregs and pDCs, both in physiological and cancer settings, as well as its potential as a therapeutic target in cancer.
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Affiliation(s)
- Belal Chaudhary
- Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, The Crescent, Peel Building G25, Manchester, M5 4WT UK
| | - Yazan S. Khaled
- Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, The Crescent, Peel Building G25, Manchester, M5 4WT UK
- Institutes of Cancer, Inflammation & Repair, University of Manchester, Manchester, UK
| | - Basil J. Ammori
- Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, The Crescent, Peel Building G25, Manchester, M5 4WT UK
- Institutes of Cancer, Inflammation & Repair, University of Manchester, Manchester, UK
| | - Eyad Elkord
- Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, The Crescent, Peel Building G25, Manchester, M5 4WT UK
- Institutes of Cancer, Inflammation & Repair, University of Manchester, Manchester, UK
- College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates
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24
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Logsdon EA, Finley SD, Popel AS, Mac Gabhann F. A systems biology view of blood vessel growth and remodelling. J Cell Mol Med 2013; 18:1491-508. [PMID: 24237862 PMCID: PMC4190897 DOI: 10.1111/jcmm.12164] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/16/2013] [Indexed: 12/29/2022] Open
Abstract
Blood travels throughout the body in an extensive network of vessels – arteries, veins and capillaries. This vascular network is not static, but instead dynamically remodels in response to stimuli from cells in the nearby tissue. In particular, the smallest vessels – arterioles, venules and capillaries – can be extended, expanded or pruned, in response to exercise, ischaemic events, pharmacological interventions, or other physiological and pathophysiological events. In this review, we describe the multi-step morphogenic process of angiogenesis – the sprouting of new blood vessels – and the stability of vascular networks in vivo. In particular, we review the known interactions between endothelial cells and the various blood cells and plasma components they convey. We describe progress that has been made in applying computational modelling, quantitative biology and high-throughput experimentation to the angiogenesis process.
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Affiliation(s)
- Elizabeth A Logsdon
- Institute for Computational Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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25
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Finley SD, Dhar M, Popel AS. Compartment model predicts VEGF secretion and investigates the effects of VEGF trap in tumor-bearing mice. Front Oncol 2013; 3:196. [PMID: 23908970 PMCID: PMC3727077 DOI: 10.3389/fonc.2013.00196] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 07/13/2013] [Indexed: 12/19/2022] Open
Abstract
Angiogenesis, the formation of new blood vessels from existing vasculature, is important in tumor growth and metastasis. A key regulator of angiogenesis is vascular endothelial growth factor (VEGF), which has been targeted in numerous anti-angiogenic therapies aimed at inhibiting tumor angiogenesis. Systems biology approaches, including computational modeling, are useful for understanding this complex biological process and can aid in the development of novel and effective therapeutics that target the VEGF family of proteins and receptors. We have developed a computational model of VEGF transport and kinetics in the tumor-bearing mouse, which includes three-compartments: normal tissue, blood, and tumor. The model simulates human tumor xenografts and includes human (VEGF121 and VEGF165) and mouse (VEGF120 and VEGF164) isoforms. The model incorporates molecular interactions between these VEGF isoforms and receptors (VEGFR1 and VEGFR2), as well as co-receptors (NRP1 and NRP2). We also include important soluble factors: soluble VEGFR1 (sFlt-1) and α-2-macroglobulin. The model accounts for transport via macromolecular transendothelial permeability, lymphatic flow, and plasma clearance. We have fit the model to available in vivo experimental data on the plasma concentration of free VEGF Trap and VEGF Trap bound to mouse and human VEGF in order to estimate the rates at which parenchymal cells (myocytes and tumor cells) and endothelial cells secrete VEGF. Interestingly, the predicted tumor VEGF secretion rates are significantly lower (0.007-0.023 molecules/cell/s, depending on the tumor microenvironment) than most reported in vitro measurements (0.03-2.65 molecules/cell/s). The optimized model is used to investigate the interstitial and plasma VEGF concentrations and the effect of the VEGF-neutralizing agent, VEGF Trap (aflibercept). This work complements experimental studies performed in mice and provides a framework with which to examine the effects of anti-VEGF agents, aiding in the optimization of such anti-angiogenic therapeutics as well as analysis of clinical data. The model predictions also have implications for biomarker discovery with anti-angiogenic therapies.
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Affiliation(s)
- Stacey D Finley
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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Expression of VEGF and semaphorin genes define subgroups of triple negative breast cancer. PLoS One 2013; 8:e61788. [PMID: 23667446 PMCID: PMC3648524 DOI: 10.1371/journal.pone.0061788] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 03/15/2013] [Indexed: 12/14/2022] Open
Abstract
Triple negative breast cancers (TNBC) are difficult to treat due to a lack of targets and heterogeneity. Inhibition of angiogenesis is a promising therapeutic strategy, but has had limited effectiveness so far in breast cancer. To quantify heterogeneity in angiogenesis-related gene expression in breast cancer, we focused on two families – VEGFs and semaphorins – that compete for neuropilin co-receptors on endothelial cells. We compiled microarray data for over 2,600 patient tumor samples and analyzed the expression of VEGF- and semaphorin-related ligands and receptors. We used principal component analysis to identify patterns of gene expression, and clustering to group samples according to these patterns. We used available survival data to determine whether these clusters had prognostic as well as therapeutic relevance. TNBC was highly associated with dysregulation of VEGF- and semaphorin-related genes; in particular, it appeared that expression of both VEGF and semaphorin genes were altered in a pro-angiogenesis direction. A pattern of high VEGFA expression with low expression of secreted semaphorins was associated with 60% of triple-negative breast tumors. While all TNBC groups demonstrated poor prognosis, this signature also correlated with lower 5-year survival rates in non-TNBC samples. A second TNBC pattern, including high VEGFC expression, was also identified. These pro-angiogenesis signatures may identify cancers that are more susceptible to VEGF inhibition.
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Bentley K, Jones M, Cruys B. Predicting the future: Towards symbiotic computational and experimental angiogenesis research. Exp Cell Res 2013; 319:1240-6. [DOI: 10.1016/j.yexcr.2013.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 02/01/2013] [Accepted: 02/02/2013] [Indexed: 01/14/2023]
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Mehta S, Moon J, Hashmi M, Leblanc M, Huang CH, Rinehart E, Wolf GT, Urba SG, Banerjee SK, Williamson S. Predictive factors in patients with advanced and metastatic squamous cell carcinoma of the head and neck: a study based on SWOG protocol S0420. Oncol Rep 2013; 29:2095-100. [PMID: 23563900 PMCID: PMC3694610 DOI: 10.3892/or.2013.2374] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/11/2012] [Indexed: 12/16/2022] Open
Abstract
To evaluate the prognostic values of different protein expression in the progression of squamous cell carcinoma of the head and neck (SCCHN) patients, we conducted immunohistochemical (IHC) analysis in tissue samples of different patients enrolled on SWOG protocol S0420. S0420 was a phase II trial to evaluate the efficacy and safety of single-agent sorafenib in chemotherapy-naïve patients with metastatic or recurrent SCCHN. The primary end point was response probability, i.e., confirmed complete (CR) and partial response (PR). Sorafenib was administered orally at 400 mg twice daily on a continuous basis in 28-day cycles to eligible patients. Responses were evaluated according to RECIST (Response Evaluation Criteria in Solid Tumors) criteria. IHC analysis was performed for various markers and data were analyzed statistically. IHC data were obtained from 19 patients enrolled on S0420. There was a high frequency of cases with expression of the angiogenesis markers SMA, HIF-1α, Raf-1, VEGF and VEGF-R. None of the markers were significantly associated with response. Negative HER-2 status was associated with longer progression-free survival (PFS), P=0.04. Negative NRP-1 status was associated with longer overall survival (OS), P=0.04. There were no other significant associations. An almost universal overexpression of angiogenesis markers in the samples analyzed supports the evaluation of angiogenesis inhibition as a potential target for therapy. High levels of NRP-1 and HER-2 in SCCHN samples appear to be associated with decreased survival and earlier progression of disease, respectively, in SCCHN patients and may represent targets for therapy.
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Affiliation(s)
- Smita Mehta
- Department of Hematology and Oncology, University of Kansas Medical Center, Westwood, KS 66205, USA
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Yang C, Guo Y, Jadlowiec CC, Li X, Lv W, Model LS, Collins MJ, Kondo Y, Muto A, Shu C, Dardik A. Vascular endothelial growth factor-A inhibits EphB4 and stimulates delta-like ligand 4 expression in adult endothelial cells. J Surg Res 2013; 183:478-86. [PMID: 23394931 DOI: 10.1016/j.jss.2013.01.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/18/2012] [Accepted: 01/03/2013] [Indexed: 10/27/2022]
Abstract
BACKGROUND During vein graft adaptation to the arterial circulation, vascular endothelial growth factor (VEGF) A expression transiently increases before becoming downregulated; however, the role of VEGF-A in venous remodeling is not clear. In addition, although VEGF-A stimulates angiogenesis and determines arterial identity in nascent arterial endothelial cells (EC), the role of VEGF-A in regulating identity in adult venous EC is also not clear. MATERIALS AND METHODS EC, wild type (EphB4+/+) or heterozygous knockout (EphB4+/-), were stimulated with VEGF-A (0-100 ng/mL) and examined with quantitative polymerase chain reaction and western blotting. RESULTS VEGF-A (100 ng/mL) inhibited expression of EphB4 and stimulated expression of delta-like ligand 4 (dll4) but did not stimulate either notch or EphrinB2 expression in adult venous EC. Pretreatment with VEGF receptor 2-neutralizing antibody abolished VEGF-stimulated downregulation of EphB4 but not the upregulation of dll4. Pretreatment with PD98059 or wortmannin showed that VEGF-A downregulation of EphB4 and upregulation of dll4 are mitogen-activated protein kinase kinase and extracellular signal-regulated kinase dependent but phosphatidylinositol 3 kinase-Akt independent. Compared with VEGF-induced EphB4 downregulation and dll4 upregulation in control EC, reduced EphB4 signaling in EphB4+/- EC showed even further downregulation of EphB4 and upregulation of dll4. CONCLUSIONS Despite the genetic programming of arterial and venous EC fate, VEGF-A can repress venous identity in adult venous EC without induction of arterial identity. These changes in adult EC in vitro recapitulate the changes in identity described during vein graft adaptation to the arterial environment in vivo.
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Affiliation(s)
- Chenzi Yang
- Interdepartmental Program in Vascular Biology and Therapeutics, Yale University School of Medicine, New Haven, Connecticut 06520-8089, USA
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Djordjevic S, Driscoll PC. Targeting VEGF signalling via the neuropilin co-receptor. Drug Discov Today 2012; 18:447-55. [PMID: 23228652 DOI: 10.1016/j.drudis.2012.11.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/20/2012] [Accepted: 11/28/2012] [Indexed: 12/14/2022]
Abstract
The blockade of tumour vascularisation and angiogenesis continues to be a focus for drug development in oncology and other pathologies. Historically, targeting vascular endothelial growth factor (VEGF) activity and its association with VEGF receptors (VEGFRs) has represented the most promising line of attack. More recently, the recognition that VEGFR co-receptors, neuropilin-1 and -2 (NRP1 and NRP2), are also engaged by specific VEGF isoforms in tandem with the VEGFRs has expanded the landscape for the development of modulators of VEGF-dependent signalling. Here, we review the recent structural characterisation of VEGF interactions with NRP subdomains and the impact this has had on drug development activity in this area.
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Affiliation(s)
- Snezana Djordjevic
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
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Hendriks BS, Reynolds JG, Klinz SG, Geretti E, Lee H, Leonard SC, Gaddy DF, Espelin CW, Nielsen UB, Wickham TJ. Multiscale kinetic modeling of liposomal Doxorubicin delivery quantifies the role of tumor and drug-specific parameters in local delivery to tumors. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2012; 1:e15. [PMID: 23835797 PMCID: PMC3600732 DOI: 10.1038/psp.2012.16] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nanoparticle encapsulation has been used as a means to manipulate the pharmacokinetic (PK) and safety profile of drugs in oncology. Using pegylated liposomal doxorubicin (PLD) vs. conventional doxorubicin as a model system, we developed and experimentally validated a multiscale computational model of liposomal drug delivery. We demonstrated that, for varying tumor transport properties, there is a regimen where liposomal and conventional doxorubicin deliver identical amounts of doxorubicin to tumor cell nuclei. In mice, typical tumor properties consistently favor improved delivery via liposomes relative to free drug. However, in humans, we predict that some tumors will have properties wherein liposomal delivery delivers the identical amount of drug to its target relative to dosing with free drug. The ability to identify tumor types and/or individual patient tumors with high degree of liposome deposition may be critical for optimizing the success of nanoparticle and liposomal anticancer therapeutics.
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Affiliation(s)
- B S Hendriks
- Merrimack Pharmaceuticals, Cambridge, Massachusetts, USA
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32
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Rizzolio S, Rabinowicz N, Rainero E, Lanzetti L, Serini G, Norman J, Neufeld G, Tamagnone L. Neuropilin-1-dependent regulation of EGF-receptor signaling. Cancer Res 2012; 72:5801-11. [PMID: 22986738 DOI: 10.1158/0008-5472.can-12-0995] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neuropilin-1 (NRP1) is a coreceptor for multiple extracellular ligands. NRP1 is widely expressed in cancer cells and in advanced human tumors; however, its functional relevance and signaling mechanisms are unclear. Here, we show that NRP1 expression controls viability and proliferation of different cancer cells, independent of its short intracellular tail. We found that the extracellular domain of NRP1 interacts with the EGF receptor (EGFR) and promotes its signaling cascade elicited upon EGF or TGF-α stimulation. Upon NRP1 silencing, the ability of ligand-bound EGFR to cluster on the cell surface, internalize, and activate the downstream AKT pathway is severely impaired. EGFR is frequently activated in human tumors due to overexpression, mutation, or sustained autocrine/paracrine stimulation. Here we show that NRP1-blocking antibodies and NRP1 silencing can counteract ligand-induced EGFR activation in cancer cells. Thus our findings unveil a novel molecular mechanism by which NRP1 can control EGFR signaling and tumor growth.
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Affiliation(s)
- Sabrina Rizzolio
- Institute for Cancer Research at Candiolo, IRC@C, and University of Torino Medical School, Candiolo, Italy
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Hamerlik P, Lathia JD, Rasmussen R, Wu Q, Bartkova J, Lee M, Moudry P, Bartek J, Fischer W, Lukas J, Rich JN, Bartek J. Autocrine VEGF-VEGFR2-Neuropilin-1 signaling promotes glioma stem-like cell viability and tumor growth. ACTA ACUST UNITED AC 2012; 209:507-20. [PMID: 22393126 PMCID: PMC3302235 DOI: 10.1084/jem.20111424] [Citation(s) in RCA: 313] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Autocrine VEGFR2 signaling in glioma stem-like cells evades VEGF neutralization. Although vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) is traditionally regarded as an endothelial cell protein, evidence suggests that VEGFRs may be expressed by cancer cells. Glioblastoma multiforme (GBM) is a lethal cancer characterized by florid vascularization and aberrantly elevated VEGF. Antiangiogenic therapy with the humanized VEGF antibody bevacizumab reduces GBM tumor growth; however, the clinical benefits are transient and invariably followed by tumor recurrence. In this study, we show that VEGFR2 is preferentially expressed on the cell surface of the CD133+ human glioma stem-like cells (GSCs), whose viability, self-renewal, and tumorigenicity rely, at least in part, on signaling through the VEGF-VEGFR2–Neuropilin-1 (NRP1) axis. We find that the limited impact of bevacizumab-mediated VEGF blockage may reflect ongoing autocrine signaling through VEGF–VEGFR2–NRP1, which is associated with VEGFR2–NRP1 recycling and a pool of active VEGFR2 within a cytosolic compartment of a subset of human GBM cells. Whereas bevacizumab failed to inhibit prosurvival effects of VEGFR2-mediated signaling, GSC viability under unperturbed or radiation-evoked stress conditions was attenuated by direct inhibition of VEGFR2 tyrosine kinase activity and/or shRNA-mediated knockdown of VEGFR2 or NRP1. We propose that direct inhibition of VEGFR2 kinase may block the highly dynamic VEGF–VEGFR2–NRP1 pathway and inspire a GBM treatment strategy to complement the currently prevalent ligand neutralization approach.
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Affiliation(s)
- Petra Hamerlik
- Danish Cancer Society Research Center and Centre for Genotoxic Stress Research, DK-2100 Copenhagen, Denmark
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Mahoney AW, Podgorski GJ, Flann NS. Multiobjective optimization based-approach for discovering novel cancer therapies. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2012; 9:169-184. [PMID: 20479506 DOI: 10.1109/tcbb.2010.39] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Solid tumors must recruit new blood vessels for growth and maintenance. Discovering drugs that block tumor-induced development of new blood vessels (angiogenesis) is an important approach in cancer treatment. The complexity of angiogenesis presents both challenges and opportunities for cancer therapies. Intuitive approaches, such as blocking VegF activity, have yielded important therapies. But there maybe opportunities to alter nonintuitive targets either alone or in combination. This paper describes the development of a high-fidelity simulation of angiogenesis and uses this as the basis for a parallel search-based approach for the discovery of novel potential cancer treatments that inhibit blood vessel growth. Discovering new therapies is viewed as a multiobjective combinatorial optimization over two competing objectives: minimizing the estimated cost of practically developing the intervention while minimizing the simulated oxygen provided to the tumor by angiogenesis. Results show the effectiveness of the search process by finding interventions that are currently in use, and more interestingly, discovering potential new approaches that are nonintuitive yet effective.
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Pharmacokinetics and pharmacodynamics of VEGF-neutralizing antibodies. BMC SYSTEMS BIOLOGY 2011; 5:193. [PMID: 22104283 PMCID: PMC3229549 DOI: 10.1186/1752-0509-5-193] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/21/2011] [Indexed: 12/20/2022]
Abstract
Background Vascular endothelial growth factor (VEGF) is a potent regulator of angiogenesis, and its role in cancer biology has been widely studied. Many cancer therapies target angiogenesis, with a focus being on VEGF-mediated signaling such as antibodies to VEGF. However, it is difficult to predict the effects of VEGF-neutralizing agents. We have developed a whole-body model of VEGF kinetics and transport under pathological conditions (in the presence of breast tumor). The model includes two major VEGF isoforms VEGF121 and VEGF165, receptors VEGFR1, VEGFR2 and co-receptors Neuropilin-1 and Neuropilin-2. We have added receptors on parenchymal cells (muscle fibers and tumor cells), and incorporated experimental data for the cell surface density of receptors on the endothelial cells, myocytes, and tumor cells. The model is applied to investigate the action of VEGF-neutralizing agents (called "anti-VEGF") in the treatment of cancer. Results Through a sensitivity study, we examine how model parameters influence the level of free VEGF in the tumor, a measure of the response to VEGF-neutralizing drugs. We investigate the effects of systemic properties such as microvascular permeability and lymphatic flow, and of drug characteristics such as the clearance rate and binding affinity. We predict that increasing microvascular permeability in the tumor above 10-5 cm/s elicits the undesired effect of increasing tumor interstitial VEGF concentration beyond even the baseline level. We also examine the impact of the tumor microenvironment, including receptor expression and internalization, as well as VEGF secretion. We find that following anti-VEGF treatment, the concentration of free VEGF in the tumor can vary between 7 and 233 pM, with a dependence on both the density of VEGF receptors and co-receptors and the rate of neuropilin internalization on tumor cells. Finally, we predict that free VEGF in the tumor is reduced following anti-VEGF treatment when VEGF121 comprises at least 25% of the VEGF secreted by tumor cells. Conclusions This study explores the optimal drug characteristics required for an anti-VEGF agent to have a therapeutic effect and the tumor-specific properties that influence the response to therapy. Our model provides a framework for investigating the use of VEGF-neutralizing drugs for personalized medicine treatment strategies.
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Saban MR, Davis CA, Avelino A, Cruz F, Maier J, Bjorling DE, Sferra TJ, Hurst RE, Saban R. VEGF signaling mediates bladder neuroplasticity and inflammation in response to BCG. BMC PHYSIOLOGY 2011; 11:16. [PMID: 22059553 PMCID: PMC3226567 DOI: 10.1186/1472-6793-11-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 11/07/2011] [Indexed: 01/13/2023]
Abstract
Background This work tests the hypothesis that increased levels of vascular endothelial growth factor (VEGF) observed during bladder inflammation modulates nerve plasticity. Methods Chronic inflammation was induced by intravesical instillations of Bacillus Calmette-Guérin (BCG) into the urinary bladder and the density of nerves expressing the transient receptor potential vanilloid subfamily 1 (TRPV1) or pan-neuronal marker PGP9.5 was used to quantify alterations in peripheral nerve plasticity. Some mice were treated with B20, a VEGF neutralizing antibody to reduce the participation of VEGF. Additional mice were treated systemically with antibodies engineered to specifically block the binding of VEGF to NRP1 (anti-NRP1B) and NRP2 (NRP2B), or the binding of semaphorins to NRP1 (anti-NRP1 A) to diminish activity of axon guidance molecules such as neuropilins (NRPs) and semaphorins (SEMAs). To confirm that VEGF is capable of inducing inflammation and neuronal plasticity, another group of mice was instilled with recombinant VEGF165 or VEGF121 into the urinary bladder. Results The major finding of this work was that chronic BCG instillation resulted in inflammation and an overwhelming increase in both PGP9.5 and TRPV1 immunoreactivity, primarily in the sub-urothelium of the urinary bladder. Treatment of mice with anti-VEGF neutralizing antibody (B20) abolished the effect of BCG on inflammation and nerve density. NRP1A and NRP1B antibodies, known to reduce BCG-induced inflammation, failed to block BCG-induced increase in nerve fibers. However, the NRP2B antibody dramatically potentiated the effects of BCG in increasing PGP9.5-, TRPV1-, substance P (SP)-, and calcitonin gene-related peptide (CGRP)-immunoreactivity (IR). Finally, instillation of VEGF121 or VEGF165 into the mouse bladder recapitulated the effects of BCG and resulted in a significant inflammation and increase in nerve density. Conclusions For the first time, evidence is being presented supporting that chronic BCG instillation into the mouse bladder promotes a significant increase in peripheral nerve density that was mimicked by VEGF instillation. Effects of BCG were abolished by pre-treatment with neutralizing VEGF antibody. The present results implicate the VEGF pathway as a key modulator of inflammation and nerve plasticity, introduces a new animal model for investigation of VEGF-induced nerve plasticity, and suggests putative mechanisms underlying this phenomenon.
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Affiliation(s)
- Marcia R Saban
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Guidolin D, Rebuffat P, Albertin G. Cell-oriented modeling of angiogenesis. ScientificWorldJournal 2011; 11:1735-48. [PMID: 22125432 PMCID: PMC3201682 DOI: 10.1100/2011/586475] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 09/12/2011] [Indexed: 12/22/2022] Open
Abstract
Due to its significant involvement in various physiological and pathological conditions, angiogenesis (the development of new blood vessels from an existing vasculature) represents an important area of the actual biological research and a field in which mathematical modeling proved particularly useful in supporting the experimental work. In this paper, we focus on a specific modeling strategy, known as "cell-centered" approach. This type of mathematical models work at a "mesoscopic scale," assuming the cell as the natural level of abstraction for computational modeling of development. They treat cells phenomenologically, considering their essential behaviors to study how tissue structure and organization emerge from the collective dynamics of multiple cells. The main contributions of the cell-oriented approach to the study of the angiogenic process will be described. From one side, they have generated "basic science understanding" about the process of capillary assembly during development, growth, and pathology. On the other side, models were also developed supporting "applied biomedical research" for the purpose of identifying new therapeutic targets and clinically relevant approaches for either inhibiting or stimulating angiogenesis.
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Affiliation(s)
- Diego Guidolin
- Department of Human Anatomy and Physiology, University of Padova Medical School, via Gabelli 65, 35121 Padova, Italy.
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Vempati P, Popel AS, Mac Gabhann F. Formation of VEGF isoform-specific spatial distributions governing angiogenesis: computational analysis. BMC SYSTEMS BIOLOGY 2011; 5:59. [PMID: 21535871 PMCID: PMC3113235 DOI: 10.1186/1752-0509-5-59] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 05/02/2011] [Indexed: 01/13/2023]
Abstract
BACKGROUND The spatial distribution of vascular endothelial growth factor A (VEGF) is an important mediator of vascular patterning. Previous experimental studies in the mouse hindbrain and retina have suggested that VEGF alternative splicing, which controls the ability of VEGF to bind to heparan sulfate proteoglycans (HSPGs) in the extracellular matrix (ECM), plays a key role in controlling VEGF diffusion and gradients in tissues. Conversely, proteolysis notably by matrix metalloproteinases (MMPs), plays a critical role in pathological situations by releasing matrix-sequestered VEGF and modulating angiogenesis. However, computational models have predicted that HSPG binding alone does not affect VEGF localization or gradients at steady state. RESULTS Using a 3D molecular-detailed reaction-diffusion model of VEGF ligand-receptor kinetics and transport, we test alternate models of VEGF transport in the extracellular environment surrounding an endothelial sprout. We show that differences in localization between VEGF isoforms, as observed experimentally in the mouse hindbrain, as well as the ability of proteases to redistribute VEGF in pathological situations, are consistent with a model where VEGF is endogenously cleared or degraded in an isoform-specific manner. We use our predictions of the VEGF distribution to quantify a tip cell's receptor binding and gradient sensing capacity. A novel prediction is that neuropilin-1, despite functioning as a coreceptor to VEGF₁₆₅-VEGFR2 binding, reduces the ability of a cell to gauge the relative steepness of the VEGF distribution. Comparing our model to available in vivo vascular patterning data suggests that vascular phenotypes are most consistently predicted at short range by the soluble fraction of the VEGF distributions, or at longer range by matrix-bound VEGF detected in a filopodia-dependent manner. CONCLUSIONS Isoform-specific VEGF degradation provides a possible explanation for numerous examples of isoform specificity in VEGF patterning and examples of proteases relocation of VEGF upon release.
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Affiliation(s)
- Prakash Vempati
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Stine MJ, Wang CJ, Moriarty WF, Ryu B, Cheong R, Westra WH, Levchenko A, Alani RM. Integration of genotypic and phenotypic screening reveals molecular mediators of melanoma-stromal interaction. Cancer Res 2011; 71:2433-44. [PMID: 21324919 DOI: 10.1158/0008-5472.can-10-1875] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Tumor-endothelium interactions are critical for tumor survival and metastasis. Melanomas can rapidly metastasize early in tumor progression, but the dependence of this aggressive behavior on tumor-stromal interaction is poorly understood. To probe the mechanisms involved, we developed a heterotypic coculture methodology, allowing simultaneous tracking of genomic and phenotypic changes in interacting tumor and endothelial cells in vitro. We found a dramatic rearrangement of endothelial cell networks into patterns reminiscent of vascular beds, even on plastic and glass. Multiple genes were upregulated in the process, many coding for cell surface and secreted proteins, including Neuropilin-2 (NRP2). A critical role of NRP2 in coordinated cell patterning and growth was confirmed using the coculture system. We conclude that NRP2 represents an important mediator of melanoma-endothelial interactions. Furthermore, the described methodology represents a powerful yet simple system to elucidate heterotypic intercellular interactions mediating diverse physiological and pathological processes.
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Affiliation(s)
- Megan J Stine
- The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Program in Cellular and Molecular Medicine, Department of Biomedical Engineering, Whitaker Institute for Biomedical Engineering, Institute for Cellular Engineering, and Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Stefanini MO, Qutub AA, Mac Gabhann F, Popel AS. Computational models of VEGF-associated angiogenic processes in cancer. MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA 2011; 29:85-94. [PMID: 21266494 DOI: 10.1093/imammb/dqq025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Tumour angiogenesis allows a growing mass of cancer cells to overcome oxygen diffusion limitation and to increase cell survival. The growth of capillaries from pre-existing blood vessels is the result of numerous signalling cascades involving different molecules and of cellular events involving multiple cell and tissue types. Computational models offer insight into the mechanisms governing angiogenesis and provide quantitative information on parameters difficult to assess by experiments alone. In this article, we summarize results from computational models of tumour angiogenic processes with a focus on the molecular-detailed vascular endothelial growth factor-associated models that have been developed in our laboratory, spanning multiple scales from the molecular to whole body.
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Affiliation(s)
- Marianne O Stefanini
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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Popel AS, Hunter PJ. Systems biology and physiome projects. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 1:153-158. [PMID: 20835988 DOI: 10.1002/wsbm.67] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Aleksander S Popel
- Systems Biology Laboratory, Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Peter J Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland 1142, New Zealand
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Saban MR, Sferra TJ, Davis CA, Simpson C, Allen A, Maier J, Fowler B, Knowlton N, Birder L, Wu XR, Saban R. Neuropilin-VEGF signaling pathway acts as a key modulator of vascular, lymphatic, and inflammatory cell responses of the bladder to intravesical BCG treatment. Am J Physiol Renal Physiol 2010; 299:F1245-56. [PMID: 20861073 DOI: 10.1152/ajprenal.00352.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Recent findings indicate that VEGF receptors and coreceptors (neuropilins; NRP) are expressed on nonendothelial cells in human bladder urothelium, in one human bladder cancer cell line (J82), and in the mouse bladder urothelium. In addition, VEGFR1, VEGFR2, NRP1, and NRP2 expressions were upregulated in animal models of chronic bladder inflammation induced by four weekly instillations of protease-activated receptors (PAR)-activating peptides or bacillus Calmette-Guérin (BCG) into the mouse bladder. Here, we used four weekly instillations of BCG as a model for chronic bladder inflammation to further investigate whether VEGF receptors and NRPs play a role in the migration of inflammatory cells and inflammation-induced lymphangiogenesis and angiogenesis. For this purpose, we used neutralizing antibodies that were engineered to specifically block the binding of VEGF to NRP (anti-NRP1(B)) and the binding of semaphorins to NRP (anti-NRP1(A)). C57BL/6 mice received intraperitoneal injections of PBS, anti-NRP1(A)- or anti-NRP1(B)-neutralizing antibodies and then were challenged chronically with intravesical PBS or BCG. At the end of chronic challenge period, a fluorescent internalizable tracer, scVEGF/Cy5.5, was administered to all mice and near-infrared fluorescence images were obtained in vivo and in real time. BCG increased the overall accumulation of scVEGF/Cy5.5 in the urinary bladder urothelium and inflammatory cells. In addition, BCG increased the density of blood and lymphatic vessels concomitantly with an upregulation of NRP2 expression in lymphatic vessels. Treatment of the mice with NRP1-neutralizing antibodies dramatically reduced scVEGF/Cy5.5 uptake, polymorphonuclear (myeloperoxidase-positive cells) and dendritic cell (CD11c-positive cells) infiltration, and decreased the overall density of BCG-induced blood and lymphatic vessels. These results implicate NRPs as critical in vivo regulators of the vascular and inflammatory responses to the intravesical administration of BCG.
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Affiliation(s)
- Marcia R Saban
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
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Wu FTH, Stefanini MO, Mac Gabhann F, Kontos CD, Annex BH, Popel AS. VEGF and soluble VEGF receptor-1 (sFlt-1) distributions in peripheral arterial disease: an in silico model. Am J Physiol Heart Circ Physiol 2010; 298:H2174-91. [PMID: 20382861 DOI: 10.1152/ajpheart.00365.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis, the growth of new capillaries from existing microvasculature. In peripheral arterial disease (PAD), lower extremity muscle ischemia develops downstream of atherosclerotic obstruction. A working hypothesis proposed that the maladaptive overexpression of soluble VEGF receptor 1 (sVEGFR1) in ischemic muscle tissues, and its subsequent antagonism of VEGF bioactivity, may contribute to the deficient angiogenic response in PAD, as well as the limited success of therapeutic angiogenesis strategies where exogenous VEGF genes/proteins are delivered. The objectives of this study were to develop a computational framework for simulating the systemic distributions of VEGF and sVEGFR1 (e.g., intramuscular vs. circulating, free vs. complexed) as observed in human PAD patients and to serve as a platform for the systematic optimization of diagnostic tools and therapeutic strategies. A three-compartment model was constructed, dividing the human body into the ischemic calf muscle, blood, and the rest of the body, connected through macromolecular biotransport processes. Detailed molecular interactions between VEGF, sVEGFR1, endothelial surface receptors (VEGFR1, VEGFR2, NRP1), and interstitial matrix sites were modeled. Our simulation results did not support a simultaneous decrease in plasma sVEGFR1 during PAD-associated elevations in plasma VEGF reported in literature. Furthermore, despite the overexpression in sVEGFR1, our PAD control demonstrated increased proangiogenic signaling complex formation, relative to our previous healthy control, due to sizeable upregulations in VEGFR2 and VEGF expression, thus leaving open the possibility that impaired angiogenesis in PAD may be rooted in signaling pathway disruptions downstream of ligand-receptor binding.
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Affiliation(s)
- Florence T H Wu
- Dept. of Biomedical Engineering, Johns Hopkins Univ. School of Medicine, 720 Rutland Ave., 613 Traylor Research Bldg., Baltimore, MD 21205, USA.
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Holtan SG, Creedon DJ, Haluska P, Markovic SN. Cancer and Pregnancy: Parallels in Growth, Invasion, and Immune Modulation and Implications for Cancer Therapeutic Agents. Mayo Clin Proc 2009. [DOI: 10.4065/84.11.985] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Holtan SG, Creedon DJ, Haluska P, Markovic SN. Cancer and pregnancy: parallels in growth, invasion, and immune modulation and implications for cancer therapeutic agents. Mayo Clin Proc 2009; 84:985-1000. [PMID: 19880689 PMCID: PMC2770910 DOI: 10.1016/s0025-6196(11)60669-1] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Many proliferative, invasive, and immune tolerance mechanisms that support normal human pregnancy are also exploited by malignancies to establish a nutrient supply and evade or edit the host immune response. In addition to the shared capacity for invading through normal tissues, both cancer cells and cells of the developing placenta create a microenvironment supportive of both immunologic privilege and angiogenesis. Systemic alterations in immunity are also detectable, particularly with respect to a helper T cell type 2 polarization evident in advanced cancers and midtrimester pregnancy. This review summarizes the similarities between growth and immune privilege in cancer and pregnancy and identifies areas for further investigation. Our PubMed search strategy included combinations of terms such as immune tolerance, pregnancy, cancer, cytokines, angiogenesis, and invasion. We did not place any restrictions on publication dates. The knowledge gained from analyzing similarities and differences between the physiologic state of pregnancy and the pathologic state of cancer could lead to identification of new potential targets for cancer therapeutic agents.
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Affiliation(s)
| | | | | | - Svetomir N. Markovic
- From the Division of Hematology (S.G.H., S.N.M.), Department of Oncology (S.G.H., P.H., S.N.M.), and Department of Obstetrics and Gynecology (D.J.C.), Mayo Clinic, Rochester, MN
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Qutub AA, Mac Gabhann F, Karagiannis ED, Vempati P, Popel AS. Multiscale models of angiogenesis. ACTA ACUST UNITED AC 2009; 28:14-31. [PMID: 19349248 DOI: 10.1109/memb.2009.931791] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Vascular disease, cancer, stroke, neurodegeneration, diabetes, inflammation, asthma, obesity, arthritis--the list of conditions that involve angiogenesis reads like main chapters in a book on pathology. Angiogenesis, the growth of capillaries from preexisting vessels, also occurs in normal physiology, in response to exercise or in the process of wound healing.Why and when is angiogenesis prevalent? What controls the process? How can we intelligently control it? These are the key questions driving researchers in fields as diverse as cell biology, oncology, cardiology, neurology, biomathematics, systems biology, and biomedical engineering. As bioengineers, we approach angiogenesis as a complex, interconnected system of events occurring in sequence and in parallel, on multiple levels, triggered by a main stimulus, e.g., hypoxia.
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Affiliation(s)
- Amina A Qutub
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
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Wu FTH, Stefanini MO, Mac Gabhann F, Popel AS. A compartment model of VEGF distribution in humans in the presence of soluble VEGF receptor-1 acting as a ligand trap. PLoS One 2009; 4:e5108. [PMID: 19352513 PMCID: PMC2663039 DOI: 10.1371/journal.pone.0005108] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 03/10/2009] [Indexed: 12/25/2022] Open
Abstract
Vascular endothelial growth factor (VEGF), through its activation of cell surface receptor tyrosine kinases including VEGFR1 and VEGFR2, is a vital regulator of stimulatory and inhibitory processes that keep angiogenesis--new capillary growth from existing microvasculature--at a dynamic balance in normal physiology. Soluble VEGF receptor-1 (sVEGFR1)--a naturally-occurring truncated version of VEGFR1 lacking the transmembrane and intracellular signaling domains--has been postulated to exert inhibitory effects on angiogenic signaling via two mechanisms: direct sequestration of angiogenic ligands such as VEGF; or dominant-negative heterodimerization with surface VEGFRs. In pre-clinical studies, sVEGFR1 gene and protein therapy have demonstrated efficacy in inhibiting tumor angiogenesis; while in clinical studies, sVEGFR1 has shown utility as a diagnostic or prognostic marker in a widening array of angiogenesis-dependent diseases. Here we developed a novel computational multi-tissue model for recapitulating the dynamic systemic distributions of VEGF and sVEGFR1. Model features included: physiologically-based multi-scale compartmentalization of the human body; inter-compartmental macromolecular biotransport processes (vascular permeability, lymphatic drainage); and molecularly-detailed binding interactions between the ligand isoforms VEGF(121) and VEGF(165), signaling receptors VEGFR1 and VEGFR2, non-signaling co-receptor neuropilin-1 (NRP1), as well as sVEGFR1. The model was parameterized to represent a healthy human subject, whereupon we investigated the effects of sVEGFR1 on the distribution and activation of VEGF ligands and receptors. We assessed the healthy baseline stability of circulating VEGF and sVEGFR1 levels in plasma, as well as their reliability in indicating tissue-level angiogenic signaling potential. Unexpectedly, simulated results showed that sVEGFR1 - acting as a diffusible VEGF sink alone, i.e., without sVEGFR1-VEGFR heterodimerization--did not significantly lower interstitial VEGF, nor inhibit signaling potential in tissues. Additionally, the sensitivity of plasma VEGF and sVEGFR1 to physiological fluctuations in transport rates may partially account for the heterogeneity in clinical measurements of these circulating angiogenic markers, potentially hindering their diagnostic reliability for diseases.
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Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
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Abstract
Several cytokine families have roles in the development, maintenance, and remodeling of the microcirculation. Of these, the vascular endothelial growth factor (VEGF) family is one of the best studied and one of the most complex. Five VEGF ligand genes and five cell-surface receptor genes are known in the human, and each of these may be transcribed as multiple splice isoforms to generate an extensive family of proteins, many of which are subject to further proteolytic processing. Using the VEGF family as an example, we describe the current knowledge of growth-factor expression, processing, and transport in vivo. Experimental studies and computational simulations are being used to measure and predict the activity of these molecules, and we describe avenues of research that seek to fill the remaining gaps in our understanding of VEGF family behavior.
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Affiliation(s)
- Feilim Mac Gabhann
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA.
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Abstract
Over the past two decades, a number of mathematical and computational models have been developed to study different aspects of angiogenesis that span the spatial and temporal scales encompassed by this complex process. For example, models have been built to investigate how growth factors and receptors signal endothelial cell proliferation, how groups of endothelial cells assemble into individual vessels, and how tumors recruit the ingrowth of whole microvascular networks. A prudent question to pose is: "what have we learned from these models?" This review aims to answer this question as it pertains to angiogenesis in the context of normal physiological growth, tumorigenesis, wound healing, tissue engineering, and the design of therapeutic strategies. We also provide a framework for parsing angiogenesis models into categories, according to the type of modeling approach used, the spatial and temporal scales simulated, and the overarching question being posed to the model. Finally, this review introduces some of the simplification strategies and assumptions used in model building, discusses model validation, and makes recommendations for application of modeling approaches to unresolved questions in the field.
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Affiliation(s)
- Shayn M Peirce
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA.
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Wu FTH, Stefanini MO, Gabhann FM, Popel AS. Modeling of growth factor-receptor systems from molecular-level protein interaction networks to whole-body compartment models. Methods Enzymol 2009; 467:461-497. [PMID: 19897104 DOI: 10.1016/s0076-6879(09)67018-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Most physiological processes are subjected to molecular regulation by growth factors, which are secreted proteins that activate chemical signal transduction pathways through binding of specific cell-surface receptors. One particular growth factor system involved in the in vivo regulation of blood vessel growth is called the vascular endothelial growth factor (VEGF) system. Computational and numerical techniques are well suited to handle the molecular complexity (the number of binding partners involved, including ligands, receptors, and inert binding sites) and multiscale nature (intratissue vs. intertissue transport and local vs. systemic effects within an organism) involved in modeling growth factor system interactions and effects. This chapter introduces a variety of in silico models that seek to recapitulate different aspects of VEGF system biology at various spatial and temporal scales: molecular-level kinetic models focus on VEGF ligand-receptor interactions at and near the endothelial cell surface; mesoscale single-tissue 3D models can simulate the effects of multicellular tissue architecture on the spatial variation in VEGF ligand production and receptor activation; compartmental modeling allows efficient prediction of average interstitial VEGF concentrations and cell-surface VEGF signaling intensities across multiple large tissue volumes, permitting the investigation of whole-body intertissue transport (e.g., vascular permeability and lymphatic drainage). The given examples will demonstrate the utility of computational models in aiding both basic science and clinical research on VEGF systems biology.
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Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Marianne O Stefanini
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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