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Li W, Liu J, Yu T, Lu F, Miao Q, Meng X, Xiao W, Yang H, Zhang X. ZDHHC9-mediated Bip/GRP78 S-palmitoylation inhibits unfolded protein response and promotes bladder cancer progression. Cancer Lett 2024; 598:217118. [PMID: 39002690 DOI: 10.1016/j.canlet.2024.217118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 07/07/2024] [Accepted: 07/09/2024] [Indexed: 07/15/2024]
Abstract
Recent studies have highlighted palmitoylation, a novel protein post-translational modification, as a key player in various signaling pathways that contribute to tumorigenesis and drug resistance. Despite this, its role in bladder cancer (BCa) development remains inadequately understood. In this study, ZDHHC9 emerged as a significantly upregulated oncogene in BCa. Functionally, ZDHHC9 knockdown markedly inhibited tumor proliferation, promoted tumor cell apoptosis, and enhanced the efficacy of gemcitabine (GEM) and cisplatin (CDDP). Mechanistically, SP1 was found to transcriptionally activate ZDHHC9 expression. ZDHHC9 subsequently bound to and palmitoylated the Bip protein at cysteine 420 (Cys420), thereby inhibiting the unfolded protein response (UPR). This palmitoylation at Cys420 enhanced Bip's protein stability and preserved its localization within the endoplasmic reticulum (ER). ZDHHC9 might become a novel therapeutic target for BCa and could also contribute to combination therapy with GEM and CDDP.
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Affiliation(s)
- Weiquan Li
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China
| | - Jingchong Liu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China
| | - Tiexi Yu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China
| | - Feiyi Lu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China
| | - Qi Miao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China
| | - Xiangui Meng
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China.
| | - Wen Xiao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China.
| | - Hongmei Yang
- Department of Pathogenic Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Xiaoping Zhang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China; Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518000, China.
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2
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Hu Z, You L, Hu S, Yu L, Gao Y, Li L, Zhang S. Hepatocellular carcinoma cell-derived exosomal miR-21-5p promotes the polarization of tumor-related macrophages (TAMs) through SP1/XBP1 and affects the progression of hepatocellular carcinoma. Int Immunopharmacol 2024; 126:111149. [PMID: 38006750 DOI: 10.1016/j.intimp.2023.111149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 10/18/2023] [Accepted: 10/28/2023] [Indexed: 11/27/2023]
Abstract
BACKGROUND Tumor-associated macrophages (TAMs) have unique functions in the development of hepatocellular carcinoma (HCC). The tumor microenvironment is in a complex state in chronic disease. As a major participant in tumor-associated inflammation, TAMs have a unique effect on promoting tumor cell proliferation, angiogenesis and immunosuppression. The in-depth study of TAMs has important scientific and clinical value and provides new ideas for the treatment of cancer. METHODS Bioinformatics analysis, dual-luciferase reporter assays, RT-qPCR and clinical samples were used to analyze the potential mechanism of the miR-21-5p/SP1/XBP1 molecular axis in HCC. In this study, miR-21-5p was highly expressed in HCC exosomes compared with normal hepatocyte exosomes, and HCC exosomes containing miR-21-5p promoted the proliferation and migration of HCC cells and inhibited cell apoptosis. In addition, this treatment promoted the M2 polarization of macrophages, induced the expression of transcription factor-specific protein 1 (SP1), and inhibited the expression of X-box binding protein 1 (XBP1). However, these expression trends were reversed after inhibition of miR-21-5p expression in exosomes of hepatoma cells, and the effects of exosomal miR-21-5p were partially restored after overexpression of SP1. Animal experiments also verified that exosomal miR-21-5p in HCC cells affected the expression level of the SP1/XBP1 protein and promoted M2 polarization of TAMs. CONCLUSION Exosomal miR-21-5p in HCC cells can affect the development of HCC cells by regulating SP1/XBP1 and promoting the M2 polarization of TAMs, thereby affecting the adverse prognostic response of HCC patients.
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Affiliation(s)
- Zongqiang Hu
- Hepato-pancreato-biliary Surgery Department, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China; The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Liying You
- The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China; Department of Hepatology, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China
| | - Songqi Hu
- Hepato-pancreato-biliary Surgery Department, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China; The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Lu Yu
- The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China; Department of Pathology, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China
| | - Yang Gao
- Hepato-pancreato-biliary Surgery Department, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China; The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China
| | - Li Li
- Hepato-pancreato-biliary Surgery Department, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China; The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China.
| | - Shengning Zhang
- Hepato-pancreato-biliary Surgery Department, First People's Hospital of Kunming City, Kunming, Yunnan 650032, China; The Calmette Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, China.
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Smedley GD, Walker KE, Yuan SH. The Role of PERK in Understanding Development of Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22158146. [PMID: 34360909 PMCID: PMC8348817 DOI: 10.3390/ijms22158146] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 01/01/2023] Open
Abstract
Neurodegenerative diseases are an ever-increasing problem for the rapidly aging population. Despite this, our understanding of how these neurodegenerative diseases develop and progress, is in most cases, rudimentary. Protein kinase RNA (PKR)-like ER kinase (PERK) comprises one of three unfolded protein response pathways in which cells attempt to manage cellular stress. However, because of its role in the cellular stress response and the far-reaching implications of this pathway, error within the PERK pathway has been shown to lead to a variety of pathologies. Genetic and clinical studies show a correlation between failure of the PERK pathway in neural cells and the development of neurodegeneration, but the wide array of methodology of these studies is presenting conflicting narratives about the role of PERK in these affected systems. Because of the connection between PERK and pathology, PERK has become a high value target of study for understanding neurodegenerative diseases and potentially how to treat them. Here, we present a review of the literature indexed in PubMed of the PERK pathway and some of the complexities involved in investigating the protein's role in the development of neurodegenerative diseases as well as how it may act as a target for therapeutics.
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Affiliation(s)
- Garrett Dalton Smedley
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
| | - Keenan E. Walker
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
| | - Shauna H. Yuan
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
- GRECC, Minneapolis VA Health Care System, Minneapolis, MN 55417, USA
- Correspondence:
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Jaud M, Philippe C, Di Bella D, Tang W, Pyronnet S, Laurell H, Mazzolini L, Rouault-Pierre K, Touriol C. Translational Regulations in Response to Endoplasmic Reticulum Stress in Cancers. Cells 2020; 9:cells9030540. [PMID: 32111004 PMCID: PMC7140484 DOI: 10.3390/cells9030540] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/18/2020] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
During carcinogenesis, almost all the biological processes are modified in one way or another. Among these biological processes affected, anomalies in protein synthesis are common in cancers. Indeed, cancer cells are subjected to a wide range of stresses, which include physical injuries, hypoxia, nutrient starvation, as well as mitotic, oxidative or genotoxic stresses. All of these stresses will cause the accumulation of unfolded proteins in the Endoplasmic Reticulum (ER), which is a major organelle that is involved in protein synthesis, preservation of cellular homeostasis, and adaptation to unfavourable environment. The accumulation of unfolded proteins in the endoplasmic reticulum causes stress triggering an unfolded protein response in order to promote cell survival or to induce apoptosis in case of chronic stress. Transcription and also translational reprogramming are tightly controlled during the unfolded protein response to ensure selective gene expression. The majority of stresses, including ER stress, induce firstly a decrease in global protein synthesis accompanied by the induction of alternative mechanisms for initiating the translation of mRNA, later followed by a translational recovery. After a presentation of ER stress and the UPR response, we will briefly present the different modes of translation initiation, then address the specific translational regulatory mechanisms acting during reticulum stress in cancers and highlight the importance of translational control by ER stress in tumours.
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Affiliation(s)
- Manon Jaud
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Céline Philippe
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Doriana Di Bella
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Weiwei Tang
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Stéphane Pyronnet
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Henrik Laurell
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Inserm UMR1048, I2MC (Institut des Maladies Métaboliques et Cardiovasculaires), BP 84225, CEDEX 04, 31 432 Toulouse, France
| | - Laurent Mazzolini
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- CNRS ERL5294, CRCT, F-31037 Toulouse, France
| | - Kevin Rouault-Pierre
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Christian Touriol
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Correspondence:
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Villalobos-Labra R, Sáez PJ, Subiabre M, Silva L, Toledo F, Westermeier F, Pardo F, Farías M, Sobrevia L. Pre-pregnancy maternal obesity associates with endoplasmic reticulum stress in human umbilical vein endothelium. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3195-3210. [PMID: 30006153 DOI: 10.1016/j.bbadis.2018.07.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/23/2018] [Accepted: 07/06/2018] [Indexed: 12/14/2022]
Abstract
Obesity associates with the endoplasmic reticulum (ER) stress-induced endothelial dysfunction. Pregnant women with pre-pregnancy maternal obesity (PGMO) may transfer this potential risk to their offspring; however, whether ER stress occurs and associates with foetoplacental endothelial dysfunction in PGMO is unknown. We studied the l-arginine transport and nitric oxide (NO) synthesis in human umbilical vein endothelial cells (HUVECs) from women with PGMO or with a normal pre-pregnancy weight. We analysed the expression and activation of the ER stress sensors protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6). PGMO associated with lower endothelial NO synthase activity due to increased Thr495-inhibitor and decreased Ser1177-stimulator phosphorylation. However, higher expression and activity of the human cationic amino acid transporter 1 was found. PGMO caused activation of PERK and its downstream targets eukaryotic initiation factor 2 (eIF2α), C/EBP homologous protein 10 (CHOP), and tribbles-like protein 3 (TRB3). Increased IRE1α protein abundance (but not its phosphorylation or X-box binding protein 1-mRNA splicing) and increased c-Jun N-terminal kinase 1 phosphorylation was seen in PGMO. A preferential nuclear location of the activating transcription factor 6 (ATF6) was found in HUVECs from PGMO. All the changes seen in PGMO were blocked by TUDCA but unaltered by tunicamycin. Thus, PGMO may determine a state of ER stress via upregulation of the PERK-eIF2α-CHOP-TRB3 axis signalling in HUVECs. This phenomenon results in foetoplacental vascular endothelial dysfunction at birth.
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Affiliation(s)
- Roberto Villalobos-Labra
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Pablo J Sáez
- Institut Curie, Paris Sciences & Lettres Research University, CNRS, UMR 144, F-75005 Paris, France
| | - Mario Subiabre
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Luis Silva
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen (UMCG), Groningen 9700, RB, the Netherlands
| | - Fernando Toledo
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán 3780000, Chile
| | - Francisco Westermeier
- FH JOANNEUM Gesellschaft mbH University of Applied Sciences, Institute of Biomedical Science, Eggenberger Allee 13, 8020 Graz, Austria
| | - Fabián Pardo
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Metabolic Diseases Research Laboratory, Center of Research, Development and Innovation in Health - Aconcagua Valley, San Felipe Campus, School of Medicine, Faculty of Medicine, Universidad de Valparaíso, San Felipe 2172972, Chile
| | - Marcelo Farías
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston QLD 4029, Queensland, Australia.
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6
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Gong J, Wang XZ, Wang T, Chen JJ, Xie XY, Hu H, Yu F, Liu HL, Jiang XY, Fan HD. Molecular signal networks and regulating mechanisms of the unfolded protein response. J Zhejiang Univ Sci B 2017; 18:1-14. [PMID: 28070992 DOI: 10.1631/jzus.b1600043] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Within the cell, several mechanisms exist to maintain homeostasis of the endoplasmic reticulum (ER). One of the primary mechanisms is the unfolded protein response (UPR). In this review, we primarily focus on the latest signal webs and regulation mechanisms of the UPR. The relationships among ER stress, apoptosis, and cancer are also discussed. Under the normal state, binding immunoglobulin protein (BiP) interacts with the three sensors (protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1α (IRE1α)). Under ER stress, misfolded proteins interact with BiP, resulting in the release of BiP from the sensors. Subsequently, the three sensors dimerize and autophosphorylate to promote the signal cascades of ER stress. ER stress includes a series of positive and negative feedback signals, such as those regulating the stabilization of the sensors/BiP complex, activating and inactivating the sensors by autophosphorylation and dephosphorylation, activating specific transcription factors to enable selective transcription, and augmenting the ability to refold and export. Apart from the three basic pathways, vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR)-phospholipase C-γ (PLCγ)-mammalian target of rapamycin complex 1 (mTORC1) pathway, induced only in solid tumors, can also activate ATF6 and PERK signal cascades, and IRE1α also can be activated by activated RAC-alpha serine/threonine-protein kinase (AKT). A moderate UPR functions as a pro-survival signal to return the cell to its state of homeostasis. However, persistent ER stress will induce cells to undergo apoptosis in response to increasing reactive oxygen species (ROS), Ca2+ in the cytoplasmic matrix, and other apoptosis signal cascades, such as c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription 3 (STAT3), and P38, when cellular damage exceeds the capacity of this adaptive response.
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Affiliation(s)
- Jing Gong
- Sichuan Radio and TV University, Chengdu 610073, China
| | - Xing-Zhi Wang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Tao Wang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Jiao-Jiao Chen
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Xiao-Yuan Xie
- The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China
| | - Hui Hu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Fang Yu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Hui-Lin Liu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Xing-Yan Jiang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Han-Dong Fan
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
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7
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Werner A, Amann E, Schnitzius V, Habermeier A, Luckner-Minden C, Leuchtner N, Rupp J, Closs EI, Munder M. Induced arginine transport via cationic amino acid transporter-1 is necessary for human T-cell proliferation. Eur J Immunol 2015; 46:92-103. [PMID: 26449889 DOI: 10.1002/eji.201546047] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 09/03/2015] [Accepted: 10/05/2015] [Indexed: 11/10/2022]
Abstract
Availability of the semiessential amino acid arginine is fundamental for the efficient function of human T lymphocytes. Tumor-associated arginine deprivation, mainly induced by myeloid-derived suppressor cells, is a central mechanism of tumor immune escape from T-cell-mediated antitumor immune responses. We thus assumed that transmembranous transport of arginine must be crucial for T-cell function and studied which transporters are responsible for arginine influx into primary human T lymphocytes. Here, we show that activation via CD3 and CD28 induces arginine transport into primary human T cells. Both naïve and memory CD4(+) T cells as well as CD8(+) T cells specifically upregulated the human cationic amino acid transporter-1 (hCAT-1), with an enhanced and persistent expression under arginine starvation. When hCAT-1 induction was suppressed via siRNA transfection, arginine uptake, and cellular proliferation were impaired. In summary, our results demonstrate that hCAT-1 is a key component of efficient T-cell activation and a novel potential target structure to modulate adaptive immune responses in tumor immunity or inflammation.
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Affiliation(s)
- Anke Werner
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Eva Amann
- Third Department of Medicine (Hematology, Oncology, and Pneumology), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Vanessa Schnitzius
- Third Department of Medicine (Hematology, Oncology, and Pneumology), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Alice Habermeier
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Claudia Luckner-Minden
- Third Department of Medicine (Hematology, Oncology, and Pneumology), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nadine Leuchtner
- Third Department of Medicine (Hematology, Oncology, and Pneumology), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Johanna Rupp
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Ellen I Closs
- Department of Pharmacology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Markus Munder
- Third Department of Medicine (Hematology, Oncology, and Pneumology), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.,Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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8
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Martin L, Gardner LB. Stress-induced inhibition of nonsense-mediated RNA decay regulates intracellular cystine transport and intracellular glutathione through regulation of the cystine/glutamate exchanger SLC7A11. Oncogene 2014; 34:4211-8. [PMID: 25399695 PMCID: PMC4433865 DOI: 10.1038/onc.2014.352] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/18/2014] [Accepted: 09/11/2014] [Indexed: 12/18/2022]
Abstract
SLC7A11 encodes a subunit of the xCT cystine/glutamate amino acid transport system and plays a critical role in the generation of glutathione and the protection of cells from oxidative stress. Expression of SLC7A11 promotes tumorigenesis and chemotherapy resistance, but while SLC7A11 has been previously noted to be upregulated in hypoxic cells its regulation has not been fully delineated. We have recently shown that nonsense mediated RNA decay (NMD) is inhibited by cellular stresses generated by the tumor microenvironment, including hypoxia, and augments tumorigenesis. Here we demonstrate that the inhibition of NMD by various cellular stresses leads to the stabilization and upregulation of SLC7A11 mRNA and protein. The inhibition of NMD and upregulation of SLC7A11 augments intracellular cystine transport, and increases intracellular levels of cysteine and glutathione. Accordinglyy, the inhibition of NMD protects cells against oxidative stress via SLC7A11 upregulation. Together our studies identify a mechanism for the dynamic regulation of SLC7A11, through the stress-inhibited regulation of NMD, and add to the growing evidence that the inhibition of NMD is an adaptive response.
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Affiliation(s)
- L Martin
- Department of Medicine, New York University School of Medicine, New York, NY, USA
| | - L B Gardner
- 1] Department of Medicine, New York University School of Medicine, New York, NY, USA [2] Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA [3] NYU Perlmutter Cancer Center, New York University School of Medicine, New York, NY, USA
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9
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Balkrishna S, Bröer A, Welford SM, Hatzoglou M, Bröer S. Expression of glutamine transporter Slc38a3 (SNAT3) during acidosis is mediated by a different mechanism than tissue-specific expression. Cell Physiol Biochem 2014; 33:1591-606. [PMID: 24854847 PMCID: PMC4424794 DOI: 10.1159/000358722] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2014] [Indexed: 02/04/2023] Open
Abstract
Background Despite homeostatic pH regulation, systemic and cellular pH changes take place and strongly influence metabolic processes. Transcription of the glutamine transporter SNAT3 (Slc38a3) for instance is highly up-regulated in the kidney during metabolic acidosis to provide glutamine for ammonia production. Methods Slc38a3 promoter activity and messenger RNA stability were measured in cultured cells in response to different extracellular pH values. Results Up-regulation of SNAT3 mRNA was mediated both by the stabilization of its mRNA and by the up-regulation of gene transcription. Stabilisation of the mRNA involved a pH-response element, while enhanced transcription made use of a second pH-sensitive Sp1 binding site in addition to a constitutive Sp1 binding site. Transcriptional regulation dominated the early response to acidosis, while mRNA stability was more important for chronic adaptation. Tissue-specific expression of SNAT3, by contrast, appeared to be controlled by promoter methylation and histone modifications. Conclusions Regulation of SNAT3 gene expression by extracellular pH involves post-transcriptional and transcriptional mechanisms, the latter being distinct from the mechanisms that control the tissue-specific expression of the gene.
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Affiliation(s)
- Sarojini Balkrishna
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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10
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Brewer JW. Regulatory crosstalk within the mammalian unfolded protein response. Cell Mol Life Sci 2014; 71:1067-79. [PMID: 24135849 PMCID: PMC11113126 DOI: 10.1007/s00018-013-1490-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 09/05/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023]
Abstract
Increased demands on the protein folding capacity of the endoplasmic reticulum (ER) trigger the unfolded protein response (UPR). Comprised of a tripartite signaling system, the UPR regulates translation and gene transcription to manifest pro-adaptive and, if necessary, pro-apoptotic outcomes. The three UPR pathways, initiated by activating transcription factor 6, inositol requiring enzyme 1, and protein kinase RNA-activated-like ER kinase (PERK), direct distinct downstream signaling events. However, it is becoming increasingly clear that interplay between the cascades is vital in shaping the UPR. In particular, recent discoveries have revealed that PERK-dependent signals mediate both inter- and intra-pathway regulation within the UPR, underscoring the critical role of the PERK pathway in the cellular response to ER stress.
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Affiliation(s)
- Joseph W Brewer
- Department of Molecular and Cellular Sciences, College of Osteopathic Medicine, Liberty University, 1971 University Boulevard, Lynchburg, VA, 24515, USA,
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Cronin KR, Mangan TP, Carew JA. Upregulation of the coagulation factor VII gene during glucose deprivation is mediated by activating transcription factor 4. PLoS One 2012; 7:e40994. [PMID: 22848420 PMCID: PMC3407153 DOI: 10.1371/journal.pone.0040994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 06/15/2012] [Indexed: 12/20/2022] Open
Abstract
Background Constitutive production of blood coagulation proteins by hepatocytes is necessary for hemostasis. Stressful conditions trigger adaptive cellular responses and delay processing of most proteins, potentially affecting plasma levels of proteins secreted exclusively by hepatocytes. We examined the effect of glucose deprivation on expression of coagulation proteins by the human hepatoma cell line, HepG2. Methodology/Principal Findings Expression of coagulation factor VII, which is required for initiation of blood coagulation, was elevated by glucose deprivation, while expression of other coagulation proteins decreased. Realtime PCR and ELISA demonstrated that the relative percentage expression +/− SD of steady-state F7 mRNA and secreted factor VII antigen were significantly increased (from 100+/−15% to 188+/−27% and 100+/−8.8% to 176.3+/−17.3% respectively, p<0.001) at 24 hr of treatment. The integrated stress response was induced, as indicated by upregulation of transcription factor ATF4 and of additional stress-responsive genes. Small interfering RNAs directed against ATF4 potently reduced basal F7 expression, and prevented F7 upregulation by glucose deprivation. The response of the endogenous F7 gene was replicated in reporter gene assays, which further indicated that ATF4 effects were mediated via interaction with an amino acid response element in the F7 promoter. Conclusions/Significance Our data indicated that glucose deprivation enhanced F7 expression in a mechanism reliant on prior ATF4 upregulation primarily due to increased transcription from the ATF4 gene. Of five coagulation protein genes examined, only F7 was upregulated, suggesting that its functions may be important in a systemic response to glucose deprivation stress.
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Affiliation(s)
- Katherine R. Cronin
- Department of Research, VA Boston Healthcare System, West Roxbury, Massachusetts, United States of America
| | - Thomas P. Mangan
- Department of Research, VA Boston Healthcare System, West Roxbury, Massachusetts, United States of America
| | - Josephine A. Carew
- Department of Research, VA Boston Healthcare System, West Roxbury, Massachusetts, United States of America
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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A novel feedback loop regulates the response to endoplasmic reticulum stress via the cooperation of cytoplasmic splicing and mRNA translation. Mol Cell Biol 2012; 32:992-1003. [PMID: 22215619 DOI: 10.1128/mcb.06665-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The accumulation of unfolded proteins in the endoplasmic reticulum (ER) triggers transcriptional and translational reprogramming. This unfolded protein response (UPR) protects cells during transient stress and can lead to apoptosis during prolonged stress. Two key mediators of the UPR are PKR-like ER kinase (PERK), which phosphorylates the α subunit of eukaryotic translation initiation factor 2 (eIF2α), resulting in decreased protein synthesis, and the α subunit of inositol-requiring enzyme 1 (IRE1α), which initiates cytoplasmic splicing of the mRNA encoding the transcription factor X-box binding protein 1 (XBP1). XBP1 induces transcription of genes involved in protein quality control. This report describes cross talk between these two pathways: phosphorylation of eIF2α was required for maximal induction of spliced XBP1 (XBP1s) protein levels via a mechanism that involved stabilization of XBP1s mRNA. By using mouse embryo fibroblasts deficient in UPR signaling pathways, we demonstrate that stress-induced stabilization of XBP1s mRNA requires cytoplasmic splicing of the mRNA and inhibition of its translation. Because the XBP1s protein promotes transcription of its own gene, the UPR-induced mRNA stabilization is part of a positive feedback loop that induces XBP1s protein accumulation and transcription of target genes during stress. We propose a model in which eIF2α phosphorylation-mediated control of mRNA turnover is a molecular switch that regulates the stress response transcription program and the ER's capacity for protein folding during stress.
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