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Uzhachenko RV, Bharti V, Ouyang Z, Blevins A, Mont S, Saleh N, Lawrence HA, Shen C, Chen SC, Ayers GD, DeNardo DG, Arteaga C, Richmond A, Vilgelm AE. Metabolic modulation by CDK4/6 inhibitor promotes chemokine-mediated recruitment of T cells into mammary tumors. Cell Rep 2021; 35:109271. [PMID: 34161761 DOI: 10.1016/j.celrep.2021.109271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Uzhachenko RV, Bharti V, Ouyang Z, Blevins A, Mont S, Saleh N, Lawrence HA, Shen C, Chen SC, Ayers GD, DeNardo DG, Arteaga C, Richmond A, Vilgelm AE. Metabolic modulation by CDK4/6 inhibitor promotes chemokine-mediated recruitment of T cells into mammary tumors. Cell Rep 2021; 35:108944. [PMID: 33826903 PMCID: PMC8383195 DOI: 10.1016/j.celrep.2021.108944] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 01/08/2021] [Accepted: 03/15/2021] [Indexed: 01/15/2023] Open
Abstract
Inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6i) delay progression of metastatic breast cancer. However, complete responses are uncommon and tumors eventually relapse. Here, we show that CDK4/6i can enhance efficacy of T cell-based therapies, such as adoptive T cell transfer or T cell-activating antibodies anti-OX40/anti-4-1BB, in murine breast cancer models. This effect is driven by the induction of chemokines CCL5, CXCL9, and CXCL10 in CDK4/6i-treated tumor cells facilitating recruitment of activated CD8+ T cells, but not Tregs, into the tumor. Mechanistically, chemokine induction is associated with metabolic stress that CDK4/6i treatment induces in breast cancer cells. Despite the cell cycle arrest, CDK4/6i-treated cells retain high metabolic activity driven by deregulated PI3K/mTOR pathway. This causes cell hypertrophy and increases mitochondrial content/activity associated with oxidative stress and inflammatory stress response. Our findings uncover a link between tumor metabolic vulnerabilities and anti-tumor immunity and support further development of CDK4/6i and immunotherapy combinations.
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Affiliation(s)
- Roman V Uzhachenko
- Comprehensive Cancer Center - James, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Vijaya Bharti
- Comprehensive Cancer Center - James, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Zhufeng Ouyang
- Comprehensive Cancer Center - James, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Ashlyn Blevins
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Stacey Mont
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Nabil Saleh
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Hunter A Lawrence
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
| | - Chengli Shen
- Comprehensive Cancer Center - James, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Sheau-Chiann Chen
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Gregory D Ayers
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - David G DeNardo
- Department of Medicine, Washington University St. Louis, School of Medicine, St. Louis, MO 63110, USA
| | - Carlos Arteaga
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ann Richmond
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA; Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 37212, USA
| | - Anna E Vilgelm
- Comprehensive Cancer Center - James, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
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Blevins A, Mont S, Lawrence H, Saleh N, Chen SC, Richmond A, Vilgelm A. Abstract 2552: Senescence induced by CDK4/6 inhibition facilitates anti-tumor T cell responses. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-2552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Cancer immunotherapies have shown remarkable clinical activity across several tumor types but responses have been modest in breast cancers. This is attributed to low levels of neo-antigens in breast tumors and immunosuppressive nature of mammary tumor microenvironment. Here we investigated if we can counteract these obstacles to an effective immunotherapy by inducing senescence in breast cancer cells. Senescence is one of the physiological stress response programs characterized by loss of proliferative potential and secretion of a variety of pro-inflammatory markers which promotes identification and removal of senescent cells by the immune cells. Here we hypothesized that senescence will stimulate anti-tumor immune response by establishing immune-permissive microenvironment. We utilized immunocompetent and humanized PDX-bearing mice to investigate senescence-induced modulation of tumor secretome proteome, transcriptome and immune cell recruitment and activity. An FDA-approved small molecule CDK4/6 inhibitor was used to induce senescence. We detected induction of multiple markers of senescence after CDK4/6 inhibitor treatment of cells and tumors. Senescent cells and tumors had increased secretion of chemokines CCL4, CCL5, CXCL9, CXCL10 and CXCL11 which facilitated T cell homing into the tumor. This was a result of their transcriptional induction by NF-κB. Consequently, we observed the dynamic enrichment of tumor immune microenvironment with T cells in tumors treated with CDK4/6 inhibitor. Furthermore, the recruitment of adoptively transferred ex-vivo activated anti-tumor T cells was significantly enhanced in tumors that were treated with CDK4/6 inhibitor. Finally, CDK4/6 inhibitor-treated tumors became responsive to T cell-activating immunotherapy with antibody agonists of T cell co-stimulatory receptors OX40 and 4-1BB. In summary, our findings suggest that CDK4/6 inhibition can facilitate T cell recruitment into the mammary tumors which can lead to an improved immunotherapy response. This pre-clinical study provides rationale for clinical development of CDK4/6 inhibitors and T cell agonists and uncovers the potential of senescence-inducing approach for sensitizing tumors to immune therapy.
Citation Format: Ashlyn Blevins, Stacey Mont, Hunter Lawrence, Nabil Saleh, Sheau-Chiann Chen, Ann Richmond, Anna Vilgelm. Senescence induced by CDK4/6 inhibition facilitates anti-tumor T cell responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2552.
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Affiliation(s)
| | | | | | | | | | - Ann Richmond
- 3Tennessee Valley Healthcare System, Nashville, TN
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Smith CA, Mont S, Traver G, Sekhar KR, Crooks PA, Freeman ML. Targeting Enox1 in tumor stroma increases the efficacy of fractionated radiotherapy. Oncotarget 2018; 7:77926-77936. [PMID: 27788492 PMCID: PMC5363632 DOI: 10.18632/oncotarget.12845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/14/2016] [Indexed: 02/07/2023] Open
Abstract
The goal of this investigation was to clarify the question of whether targeting Enox1 in tumor stroma would synergistically enhance the survival of tumor-bearing mice treated with fractionated radiotherapy. Enox1, a NADH oxidase, is expressed in tumor vasculature and stroma. However, it is not expressed in many tumor types, including HT-29 colorectal carcinoma cells. Pharmacological inhibition of Enox1 in endothelial cells inhibited repair of DNA double strand breaks, as measured by γH2AX and 53BP1 foci formation, as well as neutral comet assays. For 4 consecutive days athymic mice bearing HT-29 hindlimb xenografts were injected with a small molecule inhibitor of Enox1 or solvent control. Tumors were then administered 2 Gy of x-rays. On day 5 tumors were administered a single ‘top-up’ fraction of 30 Gy, the purpose of which was to amplify intrinsic differences in the radiation fractionation regimen produced by Enox1 targeting. Pharmacological targeting of Enox1 resulted in 80% of the tumor-bearing mice surviving at 90 days compared to only 40% of tumor-bearing mice treated with solvent control. The increase in survival was not a consequence of reoxygenation, as measured by pimonidazole immunostaining. These results are interpreted to indicate that targeting of Enox1 in tumor stroma significantly enhances the effectiveness of 2 Gy fractionated radiotherapy and identifies Enox1 as a potential therapeutic target.
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Affiliation(s)
- Clayton A Smith
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Current Address: Department of Radiation Oncology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA
| | - Stacey Mont
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Geri Traver
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Konjeti R Sekhar
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Peter A Crooks
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Michael L Freeman
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Traver G, Mont S, Gius D, Lawson WE, Ding GX, Sekhar KR, Freeman ML. Loss of Nrf2 promotes alveolar type 2 cell loss in irradiated, fibrotic lung. Free Radic Biol Med 2017; 112:578-586. [PMID: 28870520 PMCID: PMC5623074 DOI: 10.1016/j.freeradbiomed.2017.08.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/28/2017] [Accepted: 08/31/2017] [Indexed: 12/21/2022]
Abstract
The development of radiation-induced pulmonary fibrosis represents a critical clinical issue limiting delivery of therapeutic doses of radiation to non-small cell lung cancer. Identification of the cell types whose injury initiates a fibrotic response and the underlying biological factors that govern that response are needed for developing strategies that prevent or mitigate fibrosis. C57BL/6 mice (wild type, Nrf2 null, Nrf2flox/flox, and Nrf2Δ/Δ; SPC-Cre) were administered a thoracic dose of 12Gy and allowed to recover for 250 days. Whole slide digital and confocal microscopy imaging of H&E, Masson's trichrome and immunostaining were used to assess tissue remodeling, collagen deposition and cell renewal/mobilization during the regenerative process. Histological assessment of irradiated, fibrotic wild type lung revealed significant loss of alveolar type 2 cells 250 days after irradiation. Type 2 cell loss and the corresponding development of fibrosis were enhanced in the Nrf2 null mouse. Yet, conditional deletion of Nrf2 in alveolar type 2 cells in irradiated lung did not impair type 2 cell survival nor yield an increased fibrotic phenotype. Instead, radiation-induced ΔNp63 stem/progenitor cell mobilization was inhibited in the Nrf2 null mouse while the propensity for radiation-induced myofibroblasts derived from alveolar type 2 cells was magnified. In summary, these results indicate that Nrf2 is an important regulator of irradiated lung's capacity to maintain alveolar type 2 cells, whose injury can initiate a fibrotic phenotype. Loss of Nrf2 inhibits ΔNp63 stem/progenitor mobilization, a key event for reconstitution of injured lung, while promoting a myofibroblast phenotype that is central for fibrosis.
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Affiliation(s)
- Geri Traver
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Stacey Mont
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - David Gius
- Department of Radiation Oncology, Driskill Graduate Program in Life Sciences, Department of Pharmacology, Robert Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - William E Lawson
- Division of Pulmonary & Critical Care, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - George X Ding
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Konjeti R Sekhar
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael L Freeman
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Mont S, Davies SS, Roberts Second LJ, Mernaugh RL, McDonald WH, Segal BH, Zackert W, Kropski JA, Blackwell TS, Sekhar KR, Galligan JJ, Massion PP, Marnett LJ, Travis EL, Freeman ML. Accumulation of isolevuglandin-modified protein in normal and fibrotic lung. Sci Rep 2016; 6:24919. [PMID: 27118599 PMCID: PMC4847119 DOI: 10.1038/srep24919] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/07/2016] [Indexed: 12/27/2022] Open
Abstract
Protein lysine modification by γ-ketoaldehyde isomers derived from arachidonic acid, termed isolevuglandins (IsoLGs), is emerging as a mechanistic link between pathogenic reactive oxygen species and disease progression. However, the questions of whether covalent modification of proteins by IsoLGs are subject to genetic regulation and the identity of IsoLG-modified proteins remain unclear. Herein we show that Nrf2 and Nox2 are key regulators of IsoLG modification in pulmonary tissue and report on the identity of proteins analyzed by LC-MS following immunoaffinity purification of IsoLG-modified proteins. Gene ontology analysis revealed that proteins in numerous cellular pathways are susceptible to IsoLG modification. Although cells tolerate basal levels of modification, exceeding them induces apoptosis. We found prominent modification in a murine model of radiation-induced pulmonary fibrosis and in idiopathic pulmonary fibrosis, two diseases considered to be promoted by gene-regulated oxidant stress. Based on these results we hypothesize that IsoLG modification is a hitherto unrecognized sequelae that contributes to radiation-induced pulmonary injury and IPF.
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Affiliation(s)
- Stacey Mont
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37240, USA.,Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Sean S Davies
- Division of Clinical Pharmacology, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - L Jackson Roberts Second
- Division of Clinical Pharmacology, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Raymond L Mernaugh
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - W Hayes McDonald
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37240, USA.,Proteomics Laboratory and Mass Spectrometry Research Center, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Brahm H Segal
- Department of Medicine, Department of Immunology, Roswell Park Cancer Institute, and University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY, 14263, USA
| | - William Zackert
- Division of Clinical Pharmacology, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Jonathan A Kropski
- Division of Pulmonary &Critical Care, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Timothy S Blackwell
- Division of Pulmonary &Critical Care, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Konjeti R Sekhar
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - James J Galligan
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Pierre P Massion
- Division of Pulmonary &Critical Care, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Lawrence J Marnett
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37240, USA.,A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Vanderbilt Institute of Chemical Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Elizabeth L Travis
- Department of Experimental Radiation Oncology, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Michael L Freeman
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
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Skrypnyk N, Chen X, Hu W, Su Y, Mont S, Yang S, Gangadhariah M, Wei S, Falck JR, Jat JL, Zent R, Capdevila JH, Pozzi A. PPARα activation can help prevent and treat non-small cell lung cancer. Cancer Res 2013; 74:621-31. [PMID: 24302581 DOI: 10.1158/0008-5472.can-13-1928] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Non-small cell lung cancer (NSCLC) not amenable to surgical resection has a high mortality rate, due to the ineffectiveness and toxicity of chemotherapy. Thus, there remains an urgent need of efficacious drugs that can combat this disease. In this study, we show that targeting the formation of proangiogenic epoxyeicosatrienoic acids (EET) by the cytochrome P450 arachidonic acid epoxygenases (Cyp2c) represents a new and safe mechanism to treat NSCLC growth and progression. In the transgenic murine K-Ras model and human orthotopic models of NSCLC, we found that Cyp2c44 could be downregulated by activating the transcription factor PPARα with the ligands bezafibrate and Wyeth-14,643. Notably, both treatments reduced primary and metastatic NSCLC growth, tumor angiogenesis, endothelial Cyp2c44 expression, and circulating EET levels. These beneficial effects were independent of the time of administration, whether before or after the onset of primary NSCLC, and they persisted after drug withdrawal, suggesting the benefits were durable. Our findings suggest that strategies to downregulate Cyp2c expression and/or its enzymatic activity may provide a safer and effective strategy to treat NSCLC. Moreover, as bezafibrate is a well-tolerated clinically approved drug used for managing lipidemia, our findings provide an immediate cue for clinical studies to evaluate the utility of PPARα ligands as safe agents for the treatment of lung cancer in humans.
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Affiliation(s)
- Nataliya Skrypnyk
- Authors' Affiliations: Departments of Medicine, Division of Nephrology, Cancer Biology, and Biochemistry, Vanderbilt University; Department of Medicine, Veterans Affairs Hospital, Nashville, Tennessee; and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas
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Borza CM, Su Y, Chen X, Yu L, Mont S, Chetyrkin S, Voziyan P, Hudson BG, Billings PC, Jo H, Bennett JS, Degrado WF, Eckes B, Zent R, Pozzi A. Inhibition of integrin α2β1 ameliorates glomerular injury. J Am Soc Nephrol 2012; 23:1027-38. [PMID: 22440900 DOI: 10.1681/asn.2011040367] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mesangial cells and podocytes express integrins α1β1 and α2β1, which are the two major collagen receptors that regulate multiple cellular functions, including extracellular matrix homeostasis. Integrin α1β1 protects from glomerular injury by negatively regulating collagen production, but the role of integrin α2β1 in renal injury is unclear. Here, we subjected wild-type and integrin α2-null mice to injury with adriamycin or partial renal ablation. In both of these models, integrin α2-null mice developed significantly less proteinuria and glomerulosclerosis. In addition, selective pharmacological inhibition of integrin α2β1 significantly reduced adriamycin-induced proteinuria, glomerular injury, and collagen deposition in wild-type mice. This inhibitor significantly reduced collagen synthesis in wild-type, but not integrin α2-null, mesangial cells in vitro, demonstrating that its effects are integrin α2β1-dependent. Taken together, these results indicate that integrin α2β1 contributes to glomerular injury by positively regulating collagen synthesis and suggest that its inhibition may be a promising strategy to reduce glomerular injury and proteinuria.
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Affiliation(s)
- Corina M Borza
- Departments of Medicine and Cancer Biology, Division of Nephrology and Hypertension, Vanderbilt University, Medical Center North, Nashville, TN 37232, USA
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Borza CM, Chen X, Mathew S, Mont S, Sanders CR, Zent R, Pozzi A. Integrin {alpha}1{beta}1 promotes caveolin-1 dephosphorylation by activating T cell protein-tyrosine phosphatase. J Biol Chem 2010; 285:40114-24. [PMID: 20940300 DOI: 10.1074/jbc.m110.156729] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrin α1β1 is a collagen receptor that down-regulates collagen and reactive oxygen species (ROS) production, and mice lacking this receptor show increased ROS levels and exacerbated glomerular sclerosis following injury. Caveolin-1 (Cav-1) is a multifunctional protein that is tyrosine-phosphorylated in response to injury and has been implicated in ROS-mediated injury. Cav-1 interacts with integrins, and integrin α1β1 binds/activates T cell protein-tyrosine phosphatase (TCPTP), which is homologous to the tyrosine phosphatase PTP1B known to dephosphorylate Cav-1. In this study, we analyzed whether phosphorylated Cav-1 (pCav-1) is a substrate of TCPTP and if integrin α1β1 is essential for promoting TCPTP-mediated Cav-1 dephosphorylation. We found that Cav-1 phosphorylation is significantly higher in cells lacking integrin α1β1 at base line and following oxidative stress. Overexpression of TCPTP leads to reduced pCav-1 levels only in cells expressing integrin α1β1. Using solid phase binding assays, we demonstrated that 1) purified Cav-1 directly interacts with TCPTP and the integrin α1 subunit, 2) pCav-1 is a substrate of TCPTP, and 3) TCPTP-mediated Cav-1 dephosphorylation is highly increased by the addition of purified integrin α1β1 or an integrin α1 cytoplasmic peptide to which TCPTP has been shown to bind. Thus, our results demonstrate that pCav-1 is a new substrate of TCPTP and that integrin α1β1 acts as a negative regulator of Cav-1 phosphorylation by activating TCPTP. This could explain the protective function of integrin α1β1 in oxidative stress-mediated damage and why integrin α1-null mice are more susceptible to fibrosis following injury.
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Affiliation(s)
- Corina M Borza
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, Tennessee 37212-2372, USA.
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Mont S, Moya A, Marinković D. A test to detect association between autosomal and sex-linked loci in random mating populations: an example with Drosophila melanogaster. Genet Sel Evol (1983) 1988; 20:417-424. [PMID: 22879336 PMCID: PMC2712505 DOI: 10.1186/1297-9686-20-4-417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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