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Yi M, Yuan Y, Ma L, Li L, Qin W, Wu B, Zheng B, Liao X, Hu G, Liu B. Inhibition of TGFβ1 activation prevents radiation-induced lung fibrosis. Clin Transl Med 2024; 14:e1546. [PMID: 38239077 PMCID: PMC10797247 DOI: 10.1002/ctm2.1546] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 12/26/2023] [Accepted: 01/03/2024] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Radiotherapy is the main treatment modality for thoracic tumours, but it may induce pulmonary fibrosis. Currently, the pathogenesis of radiation-induced pulmonary fibrosis (RIPF) is unclear, and effective treatments are lacking. Transforming growth factor beta 1 (TGFβ1) plays a central role in RIPF. We found that activated TGFβ1 had better performance for radiation pneumonitis (RP) risk prediction by detecting activated and total TGFβ1 levels in patient serum. αv integrin plays key roles in TGFβ1 activation, but the role of αv integrin-mediated TGFβ1 activation in RIPF is unclear. Here, we investigated the role of αv integrin-mediated TGFβ1 activation in RIPF and the application of the integrin antagonist cilengitide to prevent RIPF. METHODS ItgavloxP/loxP ;Pdgfrb-Cre mice were generated by conditionally knocking out Itgav in myofibroblasts, and wild-type mice were treated with cilengitide or placebo. All mice received 16 Gy of radiation or underwent a sham radiation procedure. Lung fibrosis was measured by a modified Ashcroft score and microcomputed tomography (CT). An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum TGFβ1 concentration, and total Smad2/3 and p-Smad2/3 levels were determined via Western blotting. RESULTS Conditional Itgav knockout significantly attenuated RIPF (p < .01). Hounsfield units (HUs) in the lungs were reduced in the knockout mice compared with the control mice (p < .001). Conditional Itgav knockout decreased active TGFβ1 secretion and inhibited fibroblast p-Smad2/3 expression. Exogenous active TGFβ1, but not latent TGFβ1, reversed these reductions. Furthermore, cilengitide treatment elicited similar results and prevented RIPF. CONCLUSIONS The present study revealed that conditional Itgav knockout and cilengitide treatment both significantly attenuated RIPF in mice by inhibiting αv integrin-mediated TGFβ1 activation. HIGHLIGHTS Activated TGFβ1 has a superior capacity in predicting radiation pneumonitis (RP) risk and plays a vital role in the development of radiation-induced pulmonary fibrosis (RIPF). Conditional knock out Itgav in myofibroblasts prevented mice from developing RIPF. Cilengitide alleviated the development of RIPF by inhibiting αv integrin-mediated TGFβ1 activation and may be used in targeted approaches for preventing RIPF.
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Affiliation(s)
- Minxiao Yi
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Ye Yuan
- School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Li Ma
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Long Li
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Wan Qin
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Bili Wu
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Bolong Zheng
- School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Xin Liao
- Department of Integrative MedicineTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Guangyuan Hu
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Bo Liu
- Department of OncologyTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
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Decaris ML, Schaub JR, Chen C, Cha J, Lee GG, Rexhepaj M, Ho SS, Rao V, Marlow MM, Kotak P, Budi EH, Hooi L, Wu J, Fridlib M, Martin SP, Huang S, Chen M, Muñoz M, Hom TF, Wolters PJ, Desai TJ, Rock F, Leftheris K, Morgans DJ, Lepist EI, Andre P, Lefebvre EA, Turner SM. Dual inhibition of α vβ 6 and α vβ 1 reduces fibrogenesis in lung tissue explants from patients with IPF. Respir Res 2021; 22:265. [PMID: 34666752 PMCID: PMC8524858 DOI: 10.1186/s12931-021-01863-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 10/10/2021] [Indexed: 12/11/2022] Open
Abstract
RATIONALE αv integrins, key regulators of transforming growth factor-β activation and fibrogenesis in in vivo models of pulmonary fibrosis, are expressed on abnormal epithelial cells (αvβ6) and fibroblasts (αvβ1) in fibrotic lungs. OBJECTIVES We evaluated multiple αv integrin inhibition strategies to assess which most effectively reduced fibrogenesis in explanted lung tissue from patients with idiopathic pulmonary fibrosis. METHODS Selective αvβ6 and αvβ1, dual αvβ6/αvβ1, and multi-αv integrin inhibitors were characterized for potency, selectivity, and functional activity by ligand binding, cell adhesion, and transforming growth factor-β cell activation assays. Precision-cut lung slices generated from lung explants from patients with idiopathic pulmonary fibrosis or bleomycin-challenged mouse lungs were treated with integrin inhibitors or standard-of-care drugs (nintedanib or pirfenidone) and analyzed for changes in fibrotic gene expression or TGF-β signaling. Bleomycin-challenged mice treated with dual αvβ6/αvβ1 integrin inhibitor, PLN-74809, were assessed for changes in pulmonary collagen deposition and Smad3 phosphorylation. MEASUREMENTS AND MAIN RESULTS Inhibition of integrins αvβ6 and αvβ1 was additive in reducing type I collagen gene expression in explanted lung tissue slices from patients with idiopathic pulmonary fibrosis. These data were replicated in fibrotic mouse lung tissue, with no added benefit observed from inhibition of additional αv integrins. Antifibrotic efficacy of dual αvβ6/αvβ1 integrin inhibitor PLN-74809 was confirmed in vivo, where dose-dependent inhibition of pulmonary Smad3 phosphorylation and collagen deposition was observed. PLN-74809 also, more potently, reduced collagen gene expression in fibrotic human and mouse lung slices than clinically relevant concentrations of nintedanib or pirfenidone. CONCLUSIONS In the fibrotic lung, dual inhibition of integrins αvβ6 and αvβ1 offers the optimal approach for blocking fibrogenesis resulting from integrin-mediated activation of transforming growth factor-β.
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Affiliation(s)
| | | | - Chun Chen
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Jacob Cha
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Gail G Lee
- Pliant Therapeutics, South San Francisco, CA, USA
| | | | - Steve S Ho
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Vikram Rao
- Pliant Therapeutics, South San Francisco, CA, USA
| | | | - Prerna Kotak
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Erine H Budi
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Lisa Hooi
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Jianfeng Wu
- Pliant Therapeutics, South San Francisco, CA, USA
| | | | | | - Shaoyi Huang
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Ming Chen
- Pliant Therapeutics, South San Francisco, CA, USA
| | - Manuel Muñoz
- Pliant Therapeutics, South San Francisco, CA, USA
| | | | - Paul J Wolters
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Tushar J Desai
- Department of Medicine, Stanford University, Stanford, CA, USA
| | | | | | - David J Morgans
- Pliant Therapeutics, South San Francisco, CA, USA
- Maze Therapeutics, South San Francisco, CA, USA
| | | | - Patrick Andre
- Pliant Therapeutics, South San Francisco, CA, USA
- Acceleron Pharma, Cambridge, MA, USA
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3
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Ho TC, Yeh SI, Chen SL, Tsao YP. Integrin αv and Vitronectin Prime Macrophage-Related Inflammation and Contribute the Development of Dry Eye Disease. Int J Mol Sci 2021; 22:8410. [PMID: 34445121 DOI: 10.3390/ijms22168410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 12/27/2022] Open
Abstract
Cell signaling mediated by the αv integrin plays a pivotal role in macrophage activation in various inflammatory processes, but its involvement in the pathogenesis of dry eye disease (DED) remains unclear. In a murine model of DED, we found increased αv integrin expression in ocular surface macrophages. The αv integrins inhibitor c(RGDfK) ameliorated the corneal damage caused by DED, suggesting a pathogenic role for αv integrin. Because tear hyperosmolarity induces ocular inflammation in DED, a hyperosmolar culture of murine bone marrow-derived macrophages (BMDMs) is used to reproduce inflammation in vitro. However, the expression of proinflammatory cytokine mRNA was minimal, even though αv integrin was induced. In searching for components that are involved in αv integrin-mediated inflammation but that are missing from the culture model, we showed that the levels of vitronectin (VTN), a binding ligand of αv integrins, were increased in the tear fluid and conjunctival stroma of DED animals. The addition of VTN prominently enhanced hyperosmolarity-induced inflammation in BMDMs. Mechanistically, we showed that VTN/αv integrins mediated NF-κB activation to induce inflammatory gene expression in the BMDMs. Our findings indicate that interaction the of VTN with αv integrins is a crucial step in the inflammatory process in DED and suggests a novel therapeutic target.
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Norman MU, Chow Z, Snelgrove SL, Prakongtham P, Hickey MJ. Dynamic Regulation of the Molecular Mechanisms of Regulatory T Cell Migration in Inflamed Skin. Front Immunol 2021; 12:655499. [PMID: 34040606 PMCID: PMC8143438 DOI: 10.3389/fimmu.2021.655499] [Citation(s) in RCA: 1] [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: 01/19/2021] [Accepted: 04/22/2021] [Indexed: 12/19/2022] Open
Abstract
The presence of regulatory T cells (Tregs) in skin is important in controlling inflammatory responses in this peripheral tissue. Uninflamed skin contains a population of relatively immotile Tregs often located in clusters around hair follicles. Inflammation induces a significant increase both in the abundance of Tregs within the dermis, and in the proportion of Tregs that are highly migratory. The molecular mechanisms underpinning Treg migration in the dermis are unclear. In this study we used multiphoton intravital microscopy to examine the role of RGD-binding integrins and signalling through phosphoinositide 3-kinase P110δ (PI3K p110δ) in intradermal Treg migration in resting and inflamed skin. We found that inflammation induced Treg migration was dependent on RGD-binding integrins in a context-dependent manner. αv integrin was important for Treg migration 24 hours after induction of inflammation, but contributed to Treg retention at 48 hours, while β1 integrin played a role in Treg retention at the later time point but not during the peak of inflammation. In contrast, inhibition of signalling through PI3K p110δ reduced Treg migration throughout the entire inflammatory response, and also in the absence of inflammation. Together these observations demonstrate that the molecular mechanisms controlling intradermal Treg migration vary markedly according to the phase of the inflammatory response.
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Affiliation(s)
- M Ursula Norman
- Centre for Inflammatory Diseases, Department of Medicine, Monash Medical Centre, Monash University, Clayton, VIC, Australia
| | - Zachary Chow
- Centre for Inflammatory Diseases, Department of Medicine, Monash Medical Centre, Monash University, Clayton, VIC, Australia
| | - Sarah L Snelgrove
- Centre for Inflammatory Diseases, Department of Medicine, Monash Medical Centre, Monash University, Clayton, VIC, Australia
| | - Peemapat Prakongtham
- Centre for Inflammatory Diseases, Department of Medicine, Monash Medical Centre, Monash University, Clayton, VIC, Australia
| | - Michael J Hickey
- Centre for Inflammatory Diseases, Department of Medicine, Monash Medical Centre, Monash University, Clayton, VIC, Australia
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Belli S, Franco P, Iommelli F, De Vincenzo A, Brancaccio D, Telesca M, Merlino F, Novellino E, Ranson M, Del Vecchio S, Grieco P, Carotenuto A, Stoppelli MP. Breast Tumor Cell Invasion and Pro-Invasive Activity of Cancer-Associated Fibroblasts Co-Targeted by Novel Urokinase-Derived Decapeptides. Cancers (Basel) 2020; 12:E2404. [PMID: 32847144 DOI: 10.3390/cancers12092404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/11/2020] [Accepted: 08/19/2020] [Indexed: 01/11/2023] Open
Abstract
Among peritumoral cells, cancer-associated fibroblasts (CAFs) are major facilitators of tumor progression. This study describes the effects of two urokinase-derived, novel decapeptides, denoted as Pep 1 and its cyclic derivative Pep 2. In a mouse model of tumor dissemination, using HT1080 fibrosarcoma cells, Pep 2 reduced the number and size of lung metastases. Specific binding of fluoresceinated Pep 2 to HT1080 and telomerase immortalised fibroblasts (TIF) cell surfaces was enhanced by αv overexpression or abolished by excess vitronectin, anti-αv antibodies or silencing of ITGAV αv gene, identifying αv-integrin as the Pep 2 molecular target. In 3D-organotypic assays, peptide-exposed TIFs and primary CAFs from breast carcinoma patients both exhibited a markedly reduced pro-invasive ability of either HT1080 fibrosarcoma or MDA-MB-231 mammary carcinoma cells, respectively. Furthermore, TIFs, either exposed to Pep 2, or silenced for αv integrin, were impaired in their ability to chemoattract cancer cells and to contract collagen matrices, exhibiting reduced α-smooth muscle actin (α-SMA) levels. Finally, peptide exposure of αv-expressing primary CAFs led to the downregulation of α-SMA protein and to a dramatic reduction of their pro-invasive capability. In conclusion, the ability of the novel decapeptides to interfere with tumor cell invasion directly and through the down-modulation of CAF phenotype suggests their use as lead compounds for co-targeting anti-cancer strategies.
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Askvig JM, Dalzell TS, Toumeh N, Kuball PT, Whiteman ST, Bye EW, Andersen MJ, McCarthy MG, Irmen RE, Bexell SH, Benolken MM, Maruska BL, Nordmann SE. Age-dependent increase in Thy-1 protein in the rat supraoptic nucleus. Heliyon 2020; 6:e03501. [PMID: 32181386 PMCID: PMC7066247 DOI: 10.1016/j.heliyon.2020.e03501] [Citation(s) in RCA: 1] [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: 08/12/2019] [Revised: 10/15/2019] [Accepted: 02/24/2020] [Indexed: 11/29/2022] Open
Abstract
Mature mammalian CNS neurons often do not recover successfully following injury. To this point, unilateral lesion of the hypothalamo-neurohypophysial tract results in collateral sprouting from uninjured axons of the supraoptic nucleus (SON) in 35-day-old but not in 125-day-old rats. Thus, it appears that there are age-related changes within the SON that preclude the older rat from recovering following axotomy. We hypothesize that the intrinsic capacity for axon reorganization may depend, in part, on age-related alterations in cell adhesion molecules that allow normal astrocyte-neuron interactions in the SON. In support of our hypothesis, numerous reports have shown that Thy-1 is increased in neurons at the cessation of axon outgrowth. Therefore, we compared protein levels of Thy-1 and the Thy-1 interacting integrin subunits, alpha-v (αv), beta-3 (ß3), and beta-5 (ß5), in 35- and 125-day-old SON using western blot analysis. Our results demonstrated that there was significantly more Thy-1 protein in the 125-day-old SON compared to 35-day-old SON, but no change in the protein levels of the integrin subunits. Furthermore, we localized Thy-1-, αv integrin-, ß3 integrin-, and ß5 integrin-immunoreactivity to both neurons and astrocytes in the SON. Altogether, our results suggest that the observed increase in Thy-1 protein levels in the SON with age may contribute to an environment that prevents collateral axonal sprouting in the SON of the 125-day-old rat.
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Affiliation(s)
- Jason M Askvig
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Talia S Dalzell
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Nadia Toumeh
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Phillip T Kuball
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Sara T Whiteman
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Erik W Bye
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | | | | | - Riley E Irmen
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Sydney H Bexell
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Molly M Benolken
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Brooke L Maruska
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
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7
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Matsui Y, Kon S, Funakoshi T, Miyashita T, Matsuda T, Iwasaki N. Increased expression of αv integrin as a regulator of fibrosis in Dupuytren's nodules. J Hand Surg Eur Vol 2017; 42:18-25. [PMID: 26969686 DOI: 10.1177/1753193416635489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
UNLABELLED Although Dupuytren's contracture is characterized by increased transforming growth factor-β1 (TGF-β1) and fibrosis in the palmar fascia, the relationship between TGF-β1 and integrins, which are considered to be related to fibrosis, remains unclear. We investigated the involvement of TGF-β1 and integrins in the pathological palmar fascia of Dupuytren's contracture. Seven patients underwent partial fasciectomy for treatment of this disease. The nodule and cord were isolated from the fascial tissues of the patients. Control fasciae were obtained from seven patients with carpal tunnel syndrome. Immunohistochemical analysis was performed to detect the fibrosis marker α-smooth muscle actin and integrins in the fascial tissues. The expression of TGF-β1 and integrins was assessed by real-time polymerase chain reaction. The results suggest that nodules may be areas involved in activation of fibrosis in the fascia, associated with increased expression of TGF-β1 and αv integrin. Thus, αv integrin may contribute to fibrosis in Dupuytren's contracture by activating TGF-β1. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- Y Matsui
- 1 Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - S Kon
- 2 Department of Immunology, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - T Funakoshi
- 1 Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - T Miyashita
- 2 Department of Immunology, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - T Matsuda
- 2 Department of Immunology, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - N Iwasaki
- 1 Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Milone MR, Pucci B, Bifulco K, Iannelli F, Lombardi R, Ciardiello C, Bruzzese F, Carriero MV, Budillon A. Proteomic analysis of zoledronic-acid resistant prostate cancer cells unveils novel pathways characterizing an invasive phenotype. Oncotarget 2016; 6:5324-41. [PMID: 25481874 PMCID: PMC4467152 DOI: 10.18632/oncotarget.2694] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 07/25/2014] [Accepted: 11/04/2014] [Indexed: 12/22/2022] Open
Abstract
Proteomic analysis identified differentially expressed proteins between zoledronic acid-resistant and aggressive DU145R80 prostate cancer (PCa) cells and their parental DU145 cells. Ingenuity Pathway Analysis (IPA) showed a strong relationship between the identified proteins within a network associated with cancer and with homogeneous cellular functions prevalently related with regulation of cell organization, movement and consistent with the smaller and reduced cell-cell contact morphology of DU145R80 cells. The identified proteins correlated in publically available human PCa genomic data with increased tumor expression and aggressiveness. DU145R80 exhibit also a clear increase of alpha-v-(αv) integrin, and of urokinase receptor (uPAR), both included within the same network of the identified proteins. Interestingly, the actin-rich structures localized at the cell periphery of DU145R80 cells are rich of Filamin A, one of the identified proteins and uPAR which, in turn, co-localizes with αv-integrin, in podosomes and/or invadopodia. Notably, the invasive feature of DU145R80 may be prevented by blocking anti-αv antibody. Overall, we unveil a signaling network that physically links the interior of the nucleus via the cytoskeleton to the extracellular matrix and that could dictate PCa aggressiveness suggesting novel potential prognostic markers and therapeutic targets for PCa patients.
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Affiliation(s)
- Maria Rita Milone
- Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Biagio Pucci
- Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Katia Bifulco
- Neoplastic Progression Unit, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Federica Iannelli
- Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Rita Lombardi
- Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Chiara Ciardiello
- Experimental Pharmacology Unit, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Francesca Bruzzese
- Experimental Pharmacology Unit, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Maria Vincenza Carriero
- Neoplastic Progression Unit, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
| | - Alfredo Budillon
- Centro Ricerche Oncologiche Mercogliano, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy.,Experimental Pharmacology Unit, Istituto Nazionale Tumori Fondazione G. Pascale - IRCCS, Naples, Italy
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Abstract
The epididymis is a highly convoluted tubule that connects the testis with the vas deferens, and in which mammalian sperm acquire the ability to fertilize eggs. The most proximal portion of the epididymis, or initial segment, secretes numerous factors that are critical for sperm maturation and storage. One such factor is SED1 (also known as MFG-E8) a bi-motif protein composed of two N-terminal EGF domains, the second of which contains an RGD motif, and two C-terminal discoidin domains (also known as F5/8 type C domains). Previous studies have reported that SED1 is secreted into the epididymal lumen, where it coats sperm and later facilitates sperm-egg binding. Herein, we report that SED1-null males also harbor unexpected epididymal pathologies, including detached epithelia and spermatic granulomas. We therefore examined whether SED1 has a tissue-intrinsic role in the epididymis, in addition to its role in sperm-egg adhesion. Improved fixation protocols revealed that SED1 is found in the basolateral domains of epididymal epithelial cells in vivo, and similarly, SED1 is secreted both apically and basally from polarized epididymal cells in vitro. The basolateral distribution of SED1 suggests that it may play a novel role in epididymal cell adhesion. Consistent with this, in vitro assays showed that SED1 supports epididymal cell adhesion via RGD binding to alphaV integrin receptors on epididymal epithelial cells. Finally, epididymal cells from SED1-null males showed reduced adhesion in vitro, a phenotype that can be rescued with exogenous SED1. These results suggest that SED1 facilitates epididymal cell adhesion, and that its loss leads to breakdown of the epididymal epithelium and consequent development of spermatic granulomas.
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Affiliation(s)
- Adam S Raymond
- Department of Cell Biology, Biochemistry, Cell and Developmental Biology Graduate Program, Emory University School of Medicine, Atlanta, GA 30322, USA
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