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Deng Z, Fan T, Xiao C, Tian H, Zheng Y, Li C, He J. TGF-β signaling in health, disease, and therapeutics. Signal Transduct Target Ther 2024; 9:61. [PMID: 38514615 PMCID: PMC10958066 DOI: 10.1038/s41392-024-01764-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 08/31/2023] [Accepted: 01/31/2024] [Indexed: 03/23/2024] Open
Abstract
Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.
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Affiliation(s)
- Ziqin Deng
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Tao Fan
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Chu Xiao
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - He Tian
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yujia Zheng
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Chunxiang Li
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Jie He
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
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2
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Shovlin CL, Patel D, Bielowka A, Ledermann JA, Modarresi A, Bernabeu-Herrero ME, Aldred MA, Alsafi A. MEK 1 inhibition and bleeding in hereditary haemorrhagic telangiectasia. Br J Haematol 2024; 204:361-365. [PMID: 37872650 DOI: 10.1111/bjh.19167] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023]
Affiliation(s)
- Claire L Shovlin
- National Heart and Lung Institute, Imperial College London, London, UK
- NIHR Imperial Biomedical Research Centre, London, UK
- Imperial College Healthcare NHS Trust, London, UK
| | - Dilip Patel
- National Heart and Lung Institute, Imperial College London, London, UK
- NIHR Imperial Biomedical Research Centre, London, UK
| | - Adrianna Bielowka
- National Heart and Lung Institute, Imperial College London, London, UK
- NIHR Imperial Biomedical Research Centre, London, UK
| | | | - Atieh Modarresi
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Maria E Bernabeu-Herrero
- National Heart and Lung Institute, Imperial College London, London, UK
- NIHR Imperial Biomedical Research Centre, London, UK
| | | | - Ali Alsafi
- Imperial College Healthcare NHS Trust, London, UK
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3
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Wang D, Wen X, Xu LL, Chen QX, Yan TX, Xiao HT, Xu XW. Nf1 in heart development: a potential causative gene for congenital heart disease: a narrative review. Physiol Genomics 2023; 55:415-426. [PMID: 37519249 DOI: 10.1152/physiolgenomics.00024.2023] [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: 03/27/2023] [Revised: 06/26/2023] [Accepted: 07/08/2023] [Indexed: 08/01/2023] Open
Abstract
Congenital heart disease is the most frequent congenital disorder, affecting a significant number of live births. Gaining insights into its genetic etiology could lead to a deeper understanding of this condition. Although the Nf1 gene has been identified as a potential causative gene, its role in congenital heart disease has not been thoroughly clarified. We searched and summarized evidence from cohort-based and experimental studies on the issue of Nf1 and heart development in congenital heart diseases from various databases. Available evidence demonstrates a correlation between Nf1 and congenital heart diseases, mainly pulmonary valvar stenosis. The mechanism underlying this correlation may involve dysregulation of epithelial-mesenchymal transition (EMT). The Nf1 gene affects the EMT process via multiple pathways, including directly regulating the expression of EMT-related transcription factors and indirectly regulating the EMT process by regulating the MAPK pathway. This narrative review provides a comprehensive account of the Nf1 involvement in heart development and congenital cardiovascular diseases in terms of epidemiology and potential mechanisms. RAS signaling may contribute to congenital heart disease independently or in cooperation with other signaling pathways. Efficient management of both NF1 and cardiovascular disease patients would benefit from further research into these issues.
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Affiliation(s)
- Dun Wang
- Department of Burn and Plastic Surgery, West China Hospital of Sichuan University, Chengdu, People's Republic of China
| | - Xue Wen
- Department of Burn and Plastic Surgery, West China Hospital of Sichuan University, Chengdu, People's Republic of China
| | - Li-Li Xu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, People's Republic of China
| | - Qing-Xing Chen
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, People's Republic of China
| | - Tian-Xing Yan
- Central Laboratory, National Clinical Research Center for Oral Diseases, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China
| | - Hai-Tao Xiao
- Department of Burn and Plastic Surgery, West China Hospital of Sichuan University, Chengdu, People's Republic of China
| | - Xue-Wen Xu
- Department of Burn and Plastic Surgery, West China Hospital of Sichuan University, Chengdu, People's Republic of China
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Osteogenic growth peptide enhances osteogenic differentiation of human periodontal ligament stem cells. Heliyon 2022; 8:e09936. [PMID: 35874053 PMCID: PMC9304736 DOI: 10.1016/j.heliyon.2022.e09936] [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: 12/28/2021] [Revised: 02/09/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022] Open
Abstract
Bone tissue engineering consists of three major components namely cells, scaffolds, and signaling molecules to improve bone regeneration. These integrated principles can be applied in patients suffered from bone resorption diseases, such as osteoporosis and periodontitis. Osteogenic growth peptide (OGP) is a fourteen-amino acid sequence peptide that has the potential to regenerate bone tissues. This study aimed to disseminate the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) with OGP treatment. OGP was elaborated for proliferation, cytotoxicity, osteogenic differentiation effects, and the involvement of osteogenic related signaling pathways in vitro. This study found that OGP at lower concentration shows better effects on cytotoxicity and proliferation. Moreover, OGP at concentration 0.01 nM had the most potential to differentiate hPDLSCs toward osteogenic lineage comparing with higher concentrations of OGP. The phenomenon was mainly involving transforming growth factor-beta (TGF-β), bone morphogenetic protein (BMP), Hedgehog, and Wingless-related (Wnt) pathways. Further, SB-431542 treatment demonstrated the partial involvement of OGP in regulating osteogenic differentiation of hPDLSCs. In conclusion, OGP at low concentration enhances osteogenic differentiation of hPDLSCs by governing TGF-β signaling pathway.
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5
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Advantages and drawbacks of dexamethasone in glioblastoma multiforme. Crit Rev Oncol Hematol 2022; 172:103625. [PMID: 35158070 DOI: 10.1016/j.critrevonc.2022.103625] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 12/25/2022] Open
Abstract
The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.
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Aashaq S, Batool A, Mir SA, Beigh MA, Andrabi KI, Shah ZA. TGF-β signaling: A recap of SMAD-independent and SMAD-dependent pathways. J Cell Physiol 2021; 237:59-85. [PMID: 34286853 DOI: 10.1002/jcp.30529] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/06/2021] [Accepted: 07/06/2021] [Indexed: 12/20/2022]
Abstract
Transforming growth factor-β (TGF-β) is a proinflammatory cytokine known to control a diverse array of pathological and physiological conditions during normal development and tumorigenesis. TGF-β-mediated physiological effects are heterogeneous and vary among different types of cells and environmental conditions. TGF-β serves as an antiproliferative agent and inhibits tumor development during primary stages of tumor progression; however, during the later stages, it encourages tumor development and mediates metastatic progression and chemoresistance. The fundamental elements of TGF-β signaling have been divulged more than a decade ago; however, the process by which the signals are relayed from cell surface to nucleus is very complex with additional layers added in tumor cell niches. Although the intricate understanding of TGF-β-mediated signaling pathways and their regulation are still evolving, we tried to make an attempt to summarize the TGF-β-mediated SMAD-dependent andSMAD-independent pathways. This manuscript emphasizes the functions of TGF-β as a metastatic promoter and tumor suppressor during the later and initial phases of tumor progression respectively.
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Affiliation(s)
- Sabreena Aashaq
- Department of Immunology and Molecular Medicine, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, JK, India
| | - Asiya Batool
- Division of Cancer Pharmacology, Indian Institute of Integrative Medicine, Srinagar, JK, India
| | | | | | | | - Zaffar Amin Shah
- Department of Immunology and Molecular Medicine, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, JK, India
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Sun Z, Cai S, Zabkiewicz C, Liu C, Ye L. Bone morphogenetic proteins mediate crosstalk between cancer cells and the tumour microenvironment at primary tumours and metastases (Review). Int J Oncol 2020; 56:1335-1351. [PMID: 32236571 DOI: 10.3892/ijo.2020.5030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/28/2020] [Indexed: 11/05/2022] Open
Abstract
Bone morphogenetic proteins (BMP) are pluripotent molecules, co‑ordinating cellular functions from early embryonic and postnatal development to tissue repair, regeneration and homeostasis. They are also involved in tumourigenesis, disease progression and the metastasis of various solid tumours. Emerging evidence has indicated that BMPs are able to promote disease progression and metastasis by orchestrating communication between cancer cells and the surrounding microenvironment. The interactions occur between BMPs and epidermal growth factor receptor, hepatocyte growth factor, fibroblast growth factor, vascular endothelial growth factor and extracellular matrix components. Overall, these interactions co‑ordinate the cellular functions of tumour cells and other types of cell in the tumour to promote the growth of the primary tumour, local invasion, angiogenesis and metastasis, and the establishment and survival of cancer cells in the metastatic niche. Therefore, the present study aimed to provide an informative summary of the involvement of BMPs in the tumour microenvironment.
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Affiliation(s)
- Zhiwei Sun
- VIP‑II Division of Medical Department, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education, Beijing), Peking University Cancer Hospital and Institute, Beijing 100142, P.R. China
| | - Shuo Cai
- Cardiff China Medical Research Collaborative, Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom
| | - Catherine Zabkiewicz
- Cardiff China Medical Research Collaborative, Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom
| | - Chang Liu
- Cardiff China Medical Research Collaborative, Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom
| | - Lin Ye
- Cardiff China Medical Research Collaborative, Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom
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Yoshida K, Matsuzaki K, Murata M, Yamaguchi T, Suwa K, Okazaki K. Clinico-Pathological Importance of TGF-β/Phospho-Smad Signaling during Human Hepatic Fibrocarcinogenesis. Cancers (Basel) 2018; 10:cancers10060183. [PMID: 29874844 PMCID: PMC6025395 DOI: 10.3390/cancers10060183] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/19/2018] [Accepted: 06/01/2018] [Indexed: 12/20/2022] Open
Abstract
Chronic viral hepatitis is a global public health problem, with approximately 570 million persons chronically infected. Hepatitis B and C viruses increase the risk of morbidity and mortality from liver cirrhosis, hepatocellular carcinoma (HCC), and extrahepatic complications that develop. Hepatitis virus infection induces transforming growth factor (TGF)-β, which influences microenvironments within the infected liver. TGF-β promotes liver fibrosis by up-regulating extracellular matrix production by hepatic stellate cells. TGF-β is also up-regulated in patients with HCC, in whom it contributes importantly to bringing about a favorable microenvironment for tumor growth. Thus, TGF-β is thought to be a major factor regulating liver fibrosis and carcinogenesis. Since TGF-β carries out regulatory signaling by influencing the phosphorylation of Smads, we have generated several kinds of phospho-specific antibodies to Smad2/3. Using these, we have identified three types of phospohorylated forms: COOH-terminally phosphorylated Smad2/3 (pSmad2C and pSmad3C), linker phosphorylated Smad2/3 (pSmad2L and pSmad3L), and dually phosphorylated Smad3 (pSmad2L/C and pSmad3L/C). TGF-β-mediated pSmad2/3C signaling terminates cell proliferation; on the other hand, cytokine-induced pSmad3L signaling accelerates cell proliferation and promotes fibrogenesis. This review addresses TGF-β/Smad signal transduction in chronic liver injuries and carcinogenic processes. We also discuss the reversibility of Smad signaling after antiviral therapy.
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Affiliation(s)
- Katsunori Yoshida
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
| | - Koichi Matsuzaki
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
| | - Miki Murata
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
| | - Takashi Yamaguchi
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
| | - Kanehiko Suwa
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
| | - Kazuichi Okazaki
- Department of Gastroenterology and Hepatology, Kansai Medical University 2-5-1, Shin-Machi, Hirakata, Osaka 573-1010, Japan.
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Yang TL, Lee PL, Lee DY, Wang WL, Wei SY, Lee CI, Chiu JJ. Differential regulations of fibronectin and laminin in Smad2 activation in vascular endothelial cells in response to disturbed flow. J Biomed Sci 2018; 25:1. [PMID: 29295709 PMCID: PMC5749020 DOI: 10.1186/s12929-017-0402-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Atherosclerosis occurs in arterial curvatures and branches, where the flow is disturbed with low and oscillatory shear stress (OSS). The remodeling and alterations of extracellular matrices (ECMs) and their composition is the critical step in atherogenesis. In this study, we investigated the effects of different ECM proteins on the regulation of mechanotransduction in vascular endothelial cells (ECs) in response to OSS. METHODS Through the experiments ranging from in vitro cell culture studies on effects of OSS on molecular signaling to in vivo examinations on clinical specimens from patients with coronary artery disease (CAD), we elucidated the roles of integrins and different ECMs, i.e., fibronectin (FN) and laminin (LM), in transforming growth factor (TGF)-β receptor (TβR)-mediated Smad2 activation and nuclear factor-κB (NF-κB) signaling in ECs in response to OSS and hence atherogenesis. RESULTS OSS at 0.5±12 dynes/cm2 induces sustained increases in the association of types I and II TβRs with β1 and β3 integrins in ECs grown on FN, but it only transient increases in ECs grown on LM. OSS induces a sustained activation of Smad2 in ECs on FN, but only a transient activation of Smad2 in ECs on LM. OSS-activation of Smad2 in ECs on FN regulates downstream NF-κB signaling and pro-inflammatory gene expression through the activation of β1 integrin and its association with TβRs. In contrast, OSS induces transient activations of β1 and β3 integrins in ECs on LM, which associate with type I TβR to regulate Smad2 phosphorylation, resulting in transient induction of NF-κB and pro-inflammatory gene expression. In vivo investigations on diseased human coronary arteries from CAD patients revealed that Smad2 is highly activated in ECs of atherosclerotic lesions, which is accompanied by the concomitant increase of FN rather than LM in the EC layer and neointimal region of atherosclerotic lesions. CONCLUSIONS Our findings provide new insights into the mechanisms of how OSS regulates Smad2 signaling and pro-inflammatory genes through the complex signaling networks of integrins, TβRs, and ECMs, thus illustrating the molecular basis of regional pro-inflammatory activation within disturbed flow regions in the arterial tree.
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Affiliation(s)
- Tung-Lin Yang
- Department of Life Sciences, National Central University, Jung-Li, Taoyuan, Taiwan.,Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Pei-Ling Lee
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Ding-Yu Lee
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan.,Departments of Food Science and Biological Science and Technology, China University of Science and Technology, Taipei, Taiwan
| | - Wei-Li Wang
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Shu-Yi Wei
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Chih-I Lee
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Jeng-Jiann Chiu
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan. .,Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan. .,Institute of Biomedical Engineering, National Cheng-Kung University, Tainan, Taiwan. .,College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
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Abstract
Transforming growth factor βs (TGF-βs) are closely related ligands that have pleiotropic activity on most cell types of the body. They act through common heterotetrameric TGF-β type II and type I transmembrane dual specificity kinase receptor complexes, and the outcome of signaling is context-dependent. In normal tissue, they serve a role in maintaining homeostasis. In many diseased states, particularly fibrosis and cancer, TGF-β ligands are overexpressed and the outcome of signaling is diverted toward disease progression. There has therefore been a concerted effort to develop drugs that block TGF-β signaling for therapeutic benefit. This review will cover the basics of TGF-β signaling and its biological activities relevant to oncology, present a summary of pharmacological TGF-β blockade strategies, and give an update on preclinical and clinical trials for TGF-β blockade in a variety of solid tumor types.
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Affiliation(s)
- Rosemary J Akhurst
- Department of Anatomy and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California 94158-9001
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11
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Abstract
Transforming growth factor β (TGF-β) and structurally related factors use several intracellular signaling pathways in addition to Smad signaling to regulate a wide array of cellular functions. These non-Smad signaling pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. This review summarizes the current knowledge of the mechanisms by which non-Smad signaling pathways are directly activated in response to ligand binding, how activation of these pathways impinges on Smads and non-Smad targets, and how final cellular responses are affected in response to these noncanonical signaling modes.
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Affiliation(s)
- Ying E Zhang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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12
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Pathogenic aspects and therapeutic avenues of intestinal fibrosis in Crohn's disease. Clin Sci (Lond) 2015; 129:1107-13. [PMID: 26494636 DOI: 10.1042/cs20150472] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In Crohn's disease, one of the two major forms of inflammatory bowel diseases in human beings, persistent and chronic inflammation promotes fibrotic processes thereby facilitating formation of strictures, the most common indication for surgical intervention in this disorder. The pathogenesis of Crohn's disease-associated fibrosis is not fully understood, but variants of genes involved in the recognition of microbial components/products [e.g. CARD15 (caspase-activating recruitment domain 15) and ATG16L1 (autophagy-related 16-like 1)] are associated with this phenotype, and experimental evidence suggests that intestinal fibrosis results from an altered balance between deposition of ECM (extracellular matrix) and degradation of ECM by proteases. Studies have also contributed to identify the main phenotypic and functional alterations of cells involved in the fibrogenic process, as well as molecules that stimulate such cells to produce elevated amounts of collagen and other ECM-related proteins. In the present review, we assess the current knowledge about cellular and molecular mediators of intestinal fibrosis and describe results of recent studies aimed at testing the preventive/therapeutic effect of compounds in experimental models of intestinal fibrosis.
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Hryniuk A, Grainger S, Savory JGA, Lohnes D. Cdx1 and Cdx2 function as tumor suppressors. J Biol Chem 2014; 289:33343-54. [PMID: 25320087 DOI: 10.1074/jbc.m114.583823] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In humans, colorectal cancer is often initiated through APC loss of function, which leads to crypt hyperplasia and polyposis driven by unrestricted canonical Wnt signaling. Such polyps typically arise in the colorectal region and are at risk of transforming to invasive adenocarcinomas. Although colorectal cancer is the third most common cause of cancer-related death worldwide, the processes impacting initiation, transformation, and invasion are incompletely understood. Murine APC(Min/+) mutants are often used to model colorectal cancers; however, they develop nonmetastatic tumors confined largely to the small intestine and are thus not entirely representative of the human disease. APC(Min/+) alleles can collaborate with mutations impacting other pathways to recapitulate some aspects of human colorectal cancer. To this end, we assessed APC(Min/+)-induced polyposis following somatic loss of the homeodomain transcription factor Cdx2, alone or with a Cdx1 null allele, in the adult gastrointestinal tract. APC(Min/+)-Cdx2 mutants recapitulated several aspects of human colorectal cancer, including an invasive phenotype. Notably, the concomitant loss of Cdx1 led to a significant increase in the incidence of tumors in the distal colon, relative to APC(Min/+)-Cdx2 offspring, demonstrating a previously unrecognized role for this transcription factor in colorectal tumorigenesis. These findings underscore previously unrecognized roles for Cdx members in intestinal tumorigenesis.
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Affiliation(s)
- Alexa Hryniuk
- From the Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Stephanie Grainger
- From the Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Joanne G A Savory
- From the Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - David Lohnes
- From the Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Wang Y, Simons M. Flow-regulated lymphatic vasculature development and signaling. Vasc Cell 2014; 6:14. [PMID: 25053993 PMCID: PMC4105398 DOI: 10.1186/2045-824x-6-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/29/2014] [Indexed: 12/29/2022] Open
Abstract
The role of blood flow in regulating signaling pathways and gene expression in the blood vasculature is well known. Recent studies have identified equally important roles of flow-mediated signaling in the lymphatic circulation including control of lymphatic vascular growth, remodeling, regeneration and maintenance of the lymphatic fate. In this review, we summarize these advances focusing on the role of fluid dynamics in control of lymphatic vasculature formation.
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Affiliation(s)
- Yingdi Wang
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, 300 George St, New Haven, CT 06520, USA
| | - Michael Simons
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, 300 George St, New Haven, CT 06520, USA ; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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Lin Y, Zhang B, Liang H, Lu Y, Ai X, Zhang B, Chen X. JNK inhibitor SP600125 enhances TGF-β-induced apoptosis of RBE human cholangiocarcinoma cells in a Smad-dependent manner. Mol Med Rep 2013; 8:1623-9. [PMID: 24100678 DOI: 10.3892/mmr.2013.1711] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 09/25/2013] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor β (TGF-β) signaling is pivotal for the progression of specific types of tumors at certain stages. However, the mechanism by which TGF-β is regulated by other factors remains unclear. In this study, the involvement of SP600125, an inhibitor of c-Jun N-terminal kinase (JNK), in TGF-β-induced apoptosis of the RBE human cholangiocarcinoma cell line was investigated. Exogenous TGF-β1 activated Smad and non‑Smad signaling pathways, including the JNK pathway in RBE cells, and induced apoptosis, which was inhibited by knockdown of Smad4 expression. SP600125 increased the TGF-β1‑induced phosphorylation of Smad2 and Smad3, which enhanced the TGF-β1‑induced transcriptional response and apoptosis in RBE cells. The effect of SP600125 on the transcriptional response and apoptosis was reduced by knockdown of Smad4 expression. In addition, TGF-β1‑induced apoptosis was abrogated using the pan-caspase inhibitor Z‑VAD-fmk. SP600125 promoted the TGF-β1‑induced caspase cleavage, while knockdown of Smad4 expression counteracted this effect. These results indicate that SP600125 enhances TGF-β-induced apoptosis of RBE cells through a Smad‑dependent pathway that involves Smad‑dependent caspase activation. SP600125 is hypothesized to be an ideal therapeutic candidate for treating human cholangiocarcinoma.
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Affiliation(s)
- Youzhi Lin
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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Schedlich LJ, Yenson VM, Baxter RC. TGF-β-induced expression of IGFBP-3 regulates IGF1R signaling in human osteosarcoma cells. Mol Cell Endocrinol 2013; 377:56-64. [PMID: 23831640 DOI: 10.1016/j.mce.2013.06.033] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 06/20/2013] [Accepted: 06/25/2013] [Indexed: 11/25/2022]
Abstract
Signaling pathways initiated by transforming growth factor-β (TGF-β) and insulin-like growth factors (IGFs) are important in osteosarcoma cell growth. We have investigated a role for endogenous IGF binding protein-3 (IGFBP-3) in mediating cross-talk between TGF-β receptor and type I IGF receptor (IGF1R) signaling pathways in MG-63 osteosarcoma cells. TGF-β1 indirectly activated the Ras/Raf/MAPK pathway and induced the expression of IGFBP-3, an important regulator of IGF1R activity. IGFBP-3 attenuated TGF-β1 activation of ERK1/2 and Akt in MG-63 cells, and inhibited TGF-β1-induced cell cycle progression and proliferation. This effect of IGFBP-3 was blocked by inhibiting IGF1R signaling. TGF-β1 phosphorylated Smad2 on the non-receptor substrate sites (Ser245/250/255). Blocking the TGF-β1-induced expression of IGFBP-3 enhanced pSmad2(Ser245/250/255) and increased its nuclear accumulation. These results suggest an important role for TGF-β1 in osteosarcoma cell growth, with the induction of IGFBP-3 by TGF-β1 serving in a negative-feedback loop to control cell growth by preventing activation of the IGF1R.
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Affiliation(s)
- Lynette J Schedlich
- Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
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17
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Matsuzaki K. Smad phospho-isoforms direct context-dependent TGF-β signaling. Cytokine Growth Factor Rev 2013; 24:385-99. [PMID: 23871609 DOI: 10.1016/j.cytogfr.2013.06.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/12/2013] [Indexed: 02/06/2023]
Abstract
Better understanding of TGF-β signaling has deepened our appreciation of normal epithelial cell homeostasis and its dysfunction in such human disorders as cancer and fibrosis. Smad proteins, which convey signals from TGF-β receptors to the nucleus, possess intermediate linker regions connecting Mad homology domains. Membrane-bound, cytoplasmic, and nuclear protein kinases differentially phosphorylate Smad2 and Smad3 to create C-tail (C), the linker (L), or dually (L/C) phosphorylated (p, phospho-) isoforms. According to domain-specific phosphorylation, distinct transcriptional responses, and selective metabolism, Smad phospho-isoform pathways can be grouped into 4 types: cytostatic pSmad3C signaling, mitogenic pSmad3L (Ser-213) signaling, invasive/fibrogenic pSmad2L (Ser-245/250/255)/C or pSmad3L (Ser-204)/C signaling, and mitogenic/migratory pSmad2/3L (Thr-220/179)/C signaling. We outline how responses to TGF-β change through the multiple Smad phospho-isoforms as normal epithelial cells mature from stem cells through progenitors to differentiated cells, and further reflect upon how constitutive Ras-activating mutants favor the Smad phospho-isoform pathway promoting tumor progression. Finally, clinical analyses of reversible Smad phospho-isoform signaling during human carcinogenesis could assess effectiveness of interventions aimed at reducing human cancer risk. Spatiotemporally separate, functionally different Smad phospho-isoforms have been identified in specific cells and tissues, answering long-standing questions about context-dependent TGF-β signaling.
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Affiliation(s)
- Koichi Matsuzaki
- Department of Gastroenterology and Hepatology, Kansai Medical University, 10-15 Fumizonocho, Moriguchi, Osaka 570-8506, Japan.
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18
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Leivonen SK, Lazaridis K, Decock J, Chantry A, Edwards DR, Kähäri VM. TGF-β-elicited induction of tissue inhibitor of metalloproteinases (TIMP)-3 expression in fibroblasts involves complex interplay between Smad3, p38α, and ERK1/2. PLoS One 2013; 8:e57474. [PMID: 23468994 PMCID: PMC3585359 DOI: 10.1371/journal.pone.0057474] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/22/2013] [Indexed: 12/19/2022] Open
Abstract
Transforming growth factor-β (TGF-β) promotes extracellular matrix deposition by down-regulating the expression of matrix degrading proteinases and upregulating their inhibitors. Tissue inhibitor of metalloproteinases (TIMP)-3 is an ECM-associated specific inhibitor of matrix degrading metalloproteinases. Here, we have characterized the signaling pathways mediating TGF-β-induced expression of TIMP-3. Basal and TGF-β-induced TIMP-3 mRNA expression was abolished in Smad4-deficient mouse embryonic fibroblasts and restoring Smad4 expression rescued the response. Inhibition of Smad signaling by expression of Smad7 and dominant negative Smad3 completely abolished TGF-β-elicited expression of TIMP-3 in human fibroblasts, whereas overexpression of Smad3 enhanced it. Inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activation with PD98059 and p38 mitogen-activated protein kinase activity by SB203580 resulted in suppression of TGF-β-induced TIMP-3 expression, indicating that ERK1/2 and p38 MAPK mediate the effect of TGF-β on TIMP-3 expression. Specific activation of p38α and ERK1/2 by constitutively active mutants of MKK3b or MEK1, respectively, and simultaneous co-expression of Smad3 resulted in induction of TIMP-3 expression in the absence of TGF-β indicating that Smad3 co-operates with p38 and ERK1/2 in the induction of TIMP-3 expression. These results demonstrate the complex interplay between Smad3, p38α, and ERK1/2 signaling in the regulation of TIMP-3 gene expression in fibroblasts, which may play a role in inflammation, tissue repair, and fibrosis.
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Affiliation(s)
- Suvi-Katri Leivonen
- Department of Dermatology, University of Turku, and Turku University Hospital, Turku, Finland
- MediCity Research Laboratory, University of Turku, Turku, Finland
| | | | - Julie Decock
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Andrew Chantry
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Dylan R. Edwards
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
- * E-mail: (DRE); (V-MK)
| | - Veli-Matti Kähäri
- Department of Dermatology, University of Turku, and Turku University Hospital, Turku, Finland
- MediCity Research Laboratory, University of Turku, Turku, Finland
- * E-mail: (DRE); (V-MK)
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Maeda H, Wada N, Tomokiyo A, Monnouchi S, Akamine A. Prospective potency of TGF-β1 on maintenance and regeneration of periodontal tissue. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 304:283-367. [PMID: 23809439 DOI: 10.1016/b978-0-12-407696-9.00006-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Periodontal ligament (PDL) tissue, central in the periodontium, plays crucial roles in sustaining tooth in the bone socket. Irreparable damages of this tissue provoke tooth loss, causing a decreased quality of life. The question arises as to how PDL tissue is maintained or how the lost PDL tissue can be regenerated. Stem cells included in PDL tissue (PDLSCs) are widely accepted to have the potential to maintain or regenerate the periodontium, but PDLSCs are very few in number. In recent studies, undifferentiated clonal human PDL cell lines were developed to elucidate the applicable potentials of PDLSCs for the periodontal regenerative medicine based on cell-based tissue engineering. In addition, it has been suggested that transforming growth factor-beta 1 is an eligible factor for the maintenance and regeneration of PDL tissue.
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Affiliation(s)
- Hidefumi Maeda
- Department of Endodontology, Kyushu University Hospital, Fukuoka, Japan.
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20
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Yoshida K, Matsuzaki K. Differential Regulation of TGF-β/Smad Signaling in Hepatic Stellate Cells between Acute and Chronic Liver Injuries. Front Physiol 2012. [PMID: 22457652 DOI: 10.3389/fphys]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Current evidence suggests that regulation of extracellular matrix (ECM) accumulation by fibrogenic transforming growth factor (TGF)-β and platelet-derived growth factor (PDGF) signals involves different mechanisms in acute and chronic liver injuries, even though hepatic stellate cells (HSC) are the principal effecter in both cases. As a result of chronic liver damage, HSC undergo progressive activation to become myofibroblasts (MFB)-like cells. Our current review will discuss the differential regulation of TGF-β signaling between HSC and MFB in vitro and in vivo. Smad proteins, which convey signals from TGF-β receptors to the nucleus, have intermediate linker regions between conserved Mad-homology (MH) 1 and MH2 domains. TGF-β type I receptor and Ras-associated kinases differentially phosphorylate Smad2 and Smad3 to create COOH-terminally (C), linker (L), or dually (L/C) phosphorylated (p) isoforms. After acute liver injury, TGF-β and PDGF synergistically promote collagen synthesis in the activated HSC via pSmad2L/C and pSmad3L/C pathways. To avoid unlimited ECM deposition, Smad7 induced by TGF-β negatively regulates the fibrogenic TGF-β signaling. In contrast, TGF-β and PDGF can transmit the fibrogenic pSmad2L/C and mitogenic pSmad3L signals in MFB throughout chronic liver injury, because Smad7 cannot be induced by the pSmad3L pathway. This lack of Smad7 induction might lead to constitutive fibrogenesis in MFB, which eventually develop into accelerated liver fibrosis.
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Affiliation(s)
- Katsunori Yoshida
- Department of Gastroenterology and Hepatology, Kansai Medical University Moriguchi, Osaka, Japan
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21
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Yoshida K, Matsuzaki K. Differential Regulation of TGF-β/Smad Signaling in Hepatic Stellate Cells between Acute and Chronic Liver Injuries. Front Physiol 2012; 3:53. [PMID: 22457652 PMCID: PMC3307138 DOI: 10.3389/fphys.2012.00053] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 02/26/2012] [Indexed: 12/13/2022] Open
Abstract
Current evidence suggests that regulation of extracellular matrix (ECM) accumulation by fibrogenic transforming growth factor (TGF)-β and platelet-derived growth factor (PDGF) signals involves different mechanisms in acute and chronic liver injuries, even though hepatic stellate cells (HSC) are the principal effecter in both cases. As a result of chronic liver damage, HSC undergo progressive activation to become myofibroblasts (MFB)-like cells. Our current review will discuss the differential regulation of TGF-β signaling between HSC and MFB in vitro and in vivo. Smad proteins, which convey signals from TGF-β receptors to the nucleus, have intermediate linker regions between conserved Mad-homology (MH) 1 and MH2 domains. TGF-β type I receptor and Ras-associated kinases differentially phosphorylate Smad2 and Smad3 to create COOH-terminally (C), linker (L), or dually (L/C) phosphorylated (p) isoforms. After acute liver injury, TGF-β and PDGF synergistically promote collagen synthesis in the activated HSC via pSmad2L/C and pSmad3L/C pathways. To avoid unlimited ECM deposition, Smad7 induced by TGF-β negatively regulates the fibrogenic TGF-β signaling. In contrast, TGF-β and PDGF can transmit the fibrogenic pSmad2L/C and mitogenic pSmad3L signals in MFB throughout chronic liver injury, because Smad7 cannot be induced by the pSmad3L pathway. This lack of Smad7 induction might lead to constitutive fibrogenesis in MFB, which eventually develop into accelerated liver fibrosis.
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Affiliation(s)
- Katsunori Yoshida
- Department of Gastroenterology and Hepatology, Kansai Medical University Moriguchi, Osaka, Japan
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22
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Singh M, Chaudhry P, Parent S, Asselin E. Ubiquitin-proteasomal degradation of COX-2 in TGF-β stimulated human endometrial cells is mediated through endoplasmic reticulum mannosidase I. Endocrinology 2012; 153:426-37. [PMID: 22109885 DOI: 10.1210/en.2011-1438] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cyclooxygenase (COX)-2 is a key regulatory enzyme in the production of prostaglandins (PG) during various physiological processes. Mechanisms of COX-2 regulation in human endometrial stromal cells (human endometrial stromal cells) are not fully understood. In this study, we investigate the role of TGF-β in the regulation of COX-2 in human uterine stromal cells. Each TGF-β isoform decreases COX-2 protein level in human uterine stromal cells in Smad2/3-dependent manner. The decrease in COX-2 is accompanied by a decrease in PG synthesis. Knockdown of Smad4 using specific small interfering RNA prevents the decrease in COX-2 protein, confirming that Smad pathway is implicated in the regulation of COX-2 expression in human endometrial stromal cells. Pretreatment with 26S proteasome inhibitor, MG132, significantly restores COX-2 protein and PG synthesis, indicating that COX-2 undergoes proteasomal degradation in the presence of TGF-β. In addition, each TGF-β isoform up-regulates endoplasmic reticulum (ER)-mannosidase I (ERManI) implying that COX-2 degradation is mediated through ER-associated degradation pathway in these cells. Furthermore, inhibition of ERManI activity using the mannosidase inhibitor (kifunensine), or small interfering RNA-mediated knockdown of ERManI, prevents TGF-β-induced COX-2 degradation. Taken together, these studies suggest that TGF-β promotes COX-2 degradation in a Smad-dependent manner by up-regulating the expression of ERManI and thereby enhancing ER-associated degradation and proteasomal degradation pathways.
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Affiliation(s)
- Mohan Singh
- Department of Chemistry-Biology, University of Québec at Trois-Rivières, 3351 Boulevard des Forges, Trois-Rivières, Québec, Canada
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23
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Abstract
Transforming growth factor (TGF)-β antagonizes mitogenic Ras signaling during epithelial regeneration, but TGF-β and Ras act synergistically in driving tumor progression. Insights into these apparently contradictory effects have come from recent detailed analyses of the TGF-β signaling process. Here, we summarize the different modes of TGF-β/Ras signaling in normal epithelium and neoplasms and show how perturbation of TGF-β signaling by Ras may contribute to a shift from tumor-suppressive to protumorigenic TGF-β activity during tumor progression. Smad proteins, which convey signals from TGF-β receptors to the nucleus, have intermediate linker regions between conserved Mad homology (MH) 1 and MH2 domains. TGF-β Type I receptor and Ras-associated kinases differentially phosphorylate Smad2 and Smad3 to create C-terminally (C), linker (L) or dually (L/C) phosphorylated (p) isoforms. In epithelial homeostasis, TGF-β-mediated pSmad3C signaling opposes proliferative responses induced by mitogenic signals. During carcinogenesis, activation of cytoplasmic Ras-associated kinases including mitogen-activated protein kinase confers a selective advantage on benign tumors by shifting Smad3 signaling from a tumor-suppressive pSmad3C to an oncogenic pSmad3L pathway, leading to carcinoma in situ. Finally, at the edges of advanced carcinomas invading adjacent tissues, nuclear Ras-associated kinases such as cyclin-dependent kinases, together with cytoplasmic kinases, alter TGF-β signals to more invasive and proliferative pSmad2L/C and pSmad3L/C signaling. Taken together, TGF-β signaling specificity arises from spatiotemporal dynamics of Smad phosphoisoforms. Based on these findings, we have reason to hope that pharmacologic inhibition of linker phosphorylation might suppress progression to human advanced carcinomas by switching from protumorigenic to tumor-suppressive TGF-β signaling.
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Affiliation(s)
- Koichi Matsuzaki
- Department of Gastroenterology and Hepatology, Kansai Medical University, 10-15 Fumizonocho, Moriguchi, Osaka 570-8506, Japan.
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24
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Parvani JG, Taylor MA, Schiemann WP. Noncanonical TGF-β signaling during mammary tumorigenesis. J Mammary Gland Biol Neoplasia 2011; 16:127-46. [PMID: 21448580 PMCID: PMC3723114 DOI: 10.1007/s10911-011-9207-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 03/08/2011] [Indexed: 12/16/2022] Open
Abstract
Breast cancer is a heterogeneous disease comprised of at least five major tumor subtypes that coalesce as the second leading cause of cancer death in women in the United States. Although metastasis clearly represents the most lethal characteristic of breast cancer, our understanding of the molecular mechanisms that govern this event remains inadequate. Clinically, ~30% of breast cancer patients diagnosed with early-stage disease undergo metastatic progression, an event that (a) severely limits treatment options, (b) typically results in chemoresistance and low response rates, and (c) greatly contributes to aggressive relapses and dismal survival rates. Transforming growth factor-β (TGF-β) is a pleiotropic cytokine that regulates all phases of postnatal mammary gland development, including branching morphogenesis, lactation, and involution. TGF-β also plays a prominent role in suppressing mammary tumorigenesis by preventing mammary epithelial cell (MEC) proliferation, or by inducing MEC apoptosis. Genetic and epigenetic events that transpire during mammary tumorigenesis conspire to circumvent the tumor suppressing activities of TGF-β, thereby permitting late-stage breast cancer cells to acquire invasive and metastatic phenotypes in response to TGF-β. Metastatic progression stimulated by TGF-β also relies on its ability to induce epithelial-mesenchymal transition (EMT) and the expansion of chemoresistant breast cancer stem cells. Precisely how this metamorphosis in TGF-β function comes about remains incompletely understood; however, recent findings indicate that the initiation of oncogenic TGF-β activity is contingent upon imbalances between its canonical and noncanonical signaling systems. Here we review the molecular and cellular contributions of noncanonical TGF-β effectors to mammary tumorigenesis and metastatic progression.
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MESH Headings
- Animals
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Disease Progression
- Epithelial-Mesenchymal Transition
- Female
- Humans
- Mammary Glands, Animal/growth & development
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Glands, Human/growth & development
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Signal Transduction
- Transforming Growth Factor beta/genetics
- Transforming Growth Factor beta/metabolism
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Affiliation(s)
- Jenny G Parvani
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
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25
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Smad phosphoisoform signals in acute and chronic liver injury: similarities and differences between epithelial and mesenchymal cells. Cell Tissue Res 2011; 347:225-43. [PMID: 21626291 PMCID: PMC3250618 DOI: 10.1007/s00441-011-1178-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 04/15/2011] [Indexed: 12/17/2022]
Abstract
Hepatocellular carcinoma (HCC) usually arises from hepatic fibrosis caused by chronic inflammation. In chronic liver damage, hepatic stellate cells undergo progressive activation to myofibroblasts (MFB), which are important extracellular-matrix-producing mesenchymal cells. Concomitantly, perturbation of transforming growth factor (TGF)-β signaling by pro-inflammatory cytokines in the epithelial cells of the liver (hepatocytes) promotes both fibrogenesis and carcinogenesis (fibro-carcinogenesis). Insights into fibro-carcinogenic effects on chronically damaged hepatocytes have come from recent detailed analyses of the TGF-β signaling process. Smad proteins, which convey signals from TGF-β receptors to the nucleus, have intermediate linker regions between conserved Mad homology (MH) 1 and MH2 domains. TGF-β type I receptor and pro-inflammatory cytokine-activated kinases differentially phosphorylate Smad2 and Smad3 to create phosphoisoforms phosphorylated at the COOH-terminal, linker, or both (L/C) regions. After acute liver injury, TGF-β-mediated pSmad3C signaling terminates hepatocytic proliferation induced by the pro-inflammatory cytokine-mediated mitogenic pSmad3L pathway; TGF-β and pro-inflammatory cytokines synergistically enhance collagen synthesis by activated hepatic stellate cells via pSmad2L/C and pSmad3L/C pathways. During chronic liver disease progression, pre-neoplastic hepatocytes persistently affected by TGF-β together with pro-inflammatory cytokines come to exhibit the same carcinogenic (mitogenic) pSmad3L and fibrogenic pSmad2L/C signaling as do MFB, thereby accelerating liver fibrosis while increasing risk of HCC. This review of Smad phosphoisoform-mediated signals examines similarities and differences between epithelial and mesenchymal cells in acute and chronic liver injuries and considers Smad linker phosphorylation as a potential target for the chemoprevention of fibro-carcinogenesis.
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26
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Suwanabol PA, Kent KC, Liu B. TGF-β and restenosis revisited: a Smad link. J Surg Res 2011; 167:287-97. [PMID: 21324395 PMCID: PMC3077463 DOI: 10.1016/j.jss.2010.12.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 12/12/2010] [Accepted: 12/15/2010] [Indexed: 01/17/2023]
Abstract
Despite novel surgical therapies for the treatment of atherosclerosis, restenosis continues to be a significant impediment to the long-term success of vascular interventions. Transforming growth factor-beta (TGF-β), a family of cytokines found to be up-regulated at sites of arterial injury, has long been implicated in restenosis; a role that has largely been attributed to TGF-β-mediated vascular fibrosis. However, emerging data indicate that the role of TGF-β in intimal thickening and arterial remodeling, the critical components of restenosis, is complex and multidirectional. Recent advancements have clarified the basic signaling pathway of TGF-β, making evident the need to redefine the precise role of this family of cytokines and its primary signaling pathway, Smad, in restenosis. Unraveling TGF-β signaling in intimal thickening and arterial remodeling will pave the way for a clearer understanding of restenosis and the development of innovative pharmacological therapies.
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Affiliation(s)
- Pasithorn A. Suwanabol
- Department of Surgery, Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - K. Craig Kent
- Department of Surgery, Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Bo Liu
- Department of Surgery, Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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27
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Shepherd RD, Kos SM, Rinker KD. Flow-dependent Smad2 phosphorylation and TGIF nuclear localization in human aortic endothelial cells. Am J Physiol Heart Circ Physiol 2011; 301:H98-H107. [PMID: 21490324 DOI: 10.1152/ajpheart.00668.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Endothelial cells respond to fluid flow stimulation through transient and sustained signal pathway activation. Smad2 is a signaling molecule and transcription factor in the Smad signaling pathway, traditionally associated with TGF-β. Although phosphorylation of Smad2 in the receptor-dependent COOH-terminal region is the most appreciated way Smad2 is activated to affect gene expression, phosphorylation may also occur in the MH1-MH2 linker region (L-psmad2). Here, we show that in human aortic endothelial cells (HAEC), Smad2 was both preferentially phosphorylated in the linker region and localized to the nucleus in a flow-dependent manner. The Smad corepressor transforming growth interacting factor (TGIF) was also found to have flow-dependent nuclear localization. Tissue studies confirmed this L-psmad2 generation trend in rat aorta, indicating likely importance in arterial tissue. HAEC-based inhibitor studies demonstrated that L-psmad2 levels were not related to MAPK phosphorylation, but instead followed the pattern of pAkt(473), both with and without the phosphatidylinositol 3-kinase inhibitor PI-103. Akt and Smad species were also shown to directly interact under flow relative to static controls. To further evaluate impacts of PI-103 treatment, expression profiles for two TGF-β and shear stress-dependent genes were determined and showed that mRNAs were lower from untreated 10 dyn/cm(2) than 2 dyn/cm(2) average shear stress cultures. However, upon exposure to PI-103, this trend was reversed, with a stronger response observed at 10 dyn/cm(2). Taken together, the results of this work suggest that fluid flow exposure may influence endothelial gene expression by a novel mechanism involving Akt, L-psmad2, and TGIF.
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Affiliation(s)
- Robert D Shepherd
- Univ. of Calgary, 2500 Univ. Dr. N.W., Centre for Bioengineering Research and Education, CCIT 208, Calgary AB, Canada T2N 1N4
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28
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Ottenhof NA, de Wilde RF, Maitra A, Hruban RH, Offerhaus GJA. Molecular characteristics of pancreatic ductal adenocarcinoma. PATHOLOGY RESEARCH INTERNATIONAL 2011; 2011:620601. [PMID: 21512581 PMCID: PMC3068308 DOI: 10.4061/2011/620601] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/07/2010] [Accepted: 01/10/2011] [Indexed: 12/14/2022]
Abstract
Pancreatic cancer is an almost universally lethal disease and despite extensive research over the last decades, this has not changed significantly. Nevertheless, much progress has been made in understanding the pathogenesis of pancreatic ductal adenocarcinoma (PDAC) suggesting that different therapeutic strategies based on these new insights are forthcoming. Increasing focus exists on designing the so-called targeted treatment strategies in which the genetic characteristics of a tumor guide therapy. In the past, the focus of research was on identifying the most frequently affected genes in PDAC, but with the complete sequencing of the pancreatic cancer genome the focus has shifted to defining the biological function that the altered genes play. In this paper we aimed to put the genetic alterations present in pancreatic cancer in the context of their role in signaling pathways. In addition, this paper provides an update of the recent advances made in the development of the targeted treatment approach in PDAC.
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Affiliation(s)
- Niki A. Ottenhof
- Department of Pathology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Roeland F. de Wilde
- Department of Pathology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA
| | - Anirban Maitra
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA
| | - Ralph H. Hruban
- Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA
| | - G. Johan A. Offerhaus
- Department of Pathology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- *G. Johan A. Offerhaus:
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29
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Molecular mechanisms and in vivo mouse models of skin aging associated with dermal matrix alterations. Lab Anim Res 2011; 27:1-8. [PMID: 21826153 PMCID: PMC3145984 DOI: 10.5625/lar.2011.27.1.1] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 02/25/2011] [Accepted: 02/25/2011] [Indexed: 01/26/2023] Open
Abstract
Skin is the most superficial body organ and plays an important role in protecting the body from environmental damage and in forming social relations. With the increase of the aging population in our society, dermatological and cosmetic concerns of skin aging are rapidly increasing. Skin aging is a complex process combined with intrinsic and extrinsic factors. Intrinsic or chronological skin aging results from the passage of time and is influenced by genetic factors. Extrinsic skin aging is mainly determined by UV irradiation, also called photoaging. These two types of aging processes are superimposed on sun-exposed skin, and have a common feature of causing dermal matrix alterations that mostly contribute to the formation of wrinkles, laxity, and fragility of aged skin. The dermal matrix contains extracellular matrix proteins such as collagen, elastin, and proteoglycans that confer the strength and resiliency of skin. Skin aging associated with dermal matrix alterations and atrophy can be caused by cellular senescence of dermal cells like fibroblasts, and decreased synthesis and accelerated degradation of dermal matrix components, especially collagen fibers. Both intrinsic aging and photoaging exert influence during each step of dermal matrix alteration via different mechanisms. Mouse models of skin aging have been extensively developed to elucidate intrinsic aging and photoaging processes, to validate in vitro biochemical data, and to test the effects of pharmacological tools for retarding skin aging because they have the advantages of being genetically similar to humans and are easily available.
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30
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Role of p38 MAPK pathway in BMP4-mediated Smad-dependent premature senescence in lung cancer cells. Biochem J 2011; 433:333-43. [PMID: 21050181 DOI: 10.1042/bj20100404] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BMP4 (bone morphogenetic protein 4) is a multifunctional cytokine known to exert its biological effects through a variety of signalling pathways. The diverse function of BMP4 appears to be due to multiple pathways activated by BMP4 itself. Our previous studies have demonstrated that BMP4 is able to drive lung cancer cells into a process of premature senescence; however, the signalling pathways, as well their interplays and roles associated with this process, are not well understood. To address these questions, in the present study we investigated the signalling and molecular mechanisms underlying the BMP4-induced senescence, and our data demonstrated that p38 MAPK (mitogen-activated protein kinase) and Smad pathways were necessary for this process. Meanwhile, the ERK1/2 (extracellular-signal-regulated kinase 1/2) pathway, which is required for senescence, was not activated by BMP4 in the lung cancer cell line NCI-H460. We also showed that the BMP4-responsive R-Smads (receptor-regulated Smads), i.e. Smad1 and Smad5, were necessary for the up-regulation of p16(INK)⁴(a) and p21(WAF)¹(/cip)¹ and for the induction of premature senescence. Furthermore, we found that activation of the p38 MAPK pathway by BMP4 was essential for the full activation of transcription potential of Smad1/5. Overall, the results of the present study implicate a complex co-operation between p38 MAPK and Smad pathways in BMP4-mediated premature senescence.
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Matsuzaki K, Kitano C, Murata M, Sekimoto G, Yoshida K, Uemura Y, Seki T, Taketani S, Fujisawa JI, Okazaki K. Smad2 and Smad3 phosphorylated at both linker and COOH-terminal regions transmit malignant TGF-beta signal in later stages of human colorectal cancer. Cancer Res 2009; 69:5321-30. [PMID: 19531654 DOI: 10.1158/0008-5472.can-08-4203] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transforming growth factor (TGF)-beta initially inhibits growth of mature epithelial cells. Later, however, autocrine TGF-beta signaling acts in concert with the Ras pathway to induce a proliferative and invasive phenotype. TGF-beta activates not only TGF-beta type I receptor (TbetaRI) but also Ras-associated kinases, which differentially phosphorylate the mediators Smad2 and Smad3 to create distinct phosphorylated forms: COOH-terminally phosphorylated Smad2/3 (pSmad2C and pSmad3C) and both linker and COOH-terminally phosphorylated Smad2/3 (pSmad2L/C and pSmad3L/C). In this study, we investigated actions of pSmad2L/C and pSmad3L/C in cancer progression. TGF-beta inhibited cell growth by down-regulating c-Myc oncoprotein through the pSmad2C and pSmad3C pathway; TGF-beta signaling, in turn, enhanced cell growth by up-regulating c-Myc through the cyclin-dependent kinase (CDK) 4-dependent pSmad2L/C and pSmad3L/C pathways in cell nuclei. Alternatively, TbetaRI and c-Jun NH2-terminal kinase (JNK) together created cytoplasmic pSmad2L/C, which entered the nucleus and stimulated cell invasion, partly by up-regulating matrix metalloproteinase-9. In 20 clinical samples, pSmad2L/C and pSmad3L/C showed nuclear localization at invasion fronts of all TGF-beta-producing human metastatic colorectal cancers. In vitro kinase assay confirmed that nuclear CDK4 and cytoplasmic JNK obtained from the tumor tissue could phosphorylate Smad2 or Smad3 at their linker regions. We suggest that CDK4, together with JNK, alters tumor-suppressive TGF-beta signaling to malignant characteristics in later stages of human colorectal cancer. The linker phosphorylation of Smad2 and Smad3 may represent a target for intervention in human metastatic cancer.
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Affiliation(s)
- Koichi Matsuzaki
- Department of Gastroenterology and Hepatology, Kansai Medical University, 10-15 Fumizonocho, Moriguchi, Osaka 570-8506, Japan.
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Lin X, Chen Y, Meng A, Feng X. Termination of TGF-beta superfamily signaling through SMAD dephosphorylation--a functional genomic view. J Genet Genomics 2009; 34:1-9. [PMID: 17469772 DOI: 10.1016/s1673-8527(07)60001-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 10/31/2006] [Indexed: 12/11/2022]
Abstract
The transforming growth factor-beta (TGF-beta) and related growth factors activate a broad range of cellular responses in metazoan organisms via autocrine, paracrine, and endocrine modes. They play key roles in the pathogenesis of many diseases especially cancer, fibrotic diseases, autoimmune diseases and cardiovascular diseases. TGF-beta receptor-mediated phosphorylation of R-SMADs represents the most critical step in the TGF-beta signaling pathways that triggers a cascade of intracellular events from SMAD complex assembly in the cytoplasm to transcriptional control in the nucleus. Conversely, dephosphorylation of R-SMADs is a key mechanism for terminating TGF-beta signaling. Our labs have recently taken an integrated approach combining functional genomics, biochemistry and development biology to describe the isolation and functional characterization of protein phosphatase PPM1A in controlling TGF-beta signaling. This article briefly reviews how dynamic phosphorylation and dephosphorylation of SMADs control or fine-tune the signaling strength and duration and ultimately the physiological consequences in TGF-beta signaling.
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Affiliation(s)
- Xia Lin
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston TX 77030, USA
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Kutcher ME, Herman IM. The pericyte: cellular regulator of microvascular blood flow. Microvasc Res 2009; 77:235-46. [PMID: 19323975 DOI: 10.1016/j.mvr.2009.01.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 01/14/2009] [Accepted: 01/15/2009] [Indexed: 01/03/2023]
Abstract
The vascular system - through its development, response to injury, and remodeling during disease - constitutes one of the key organ systems sustaining normal human physiology; conversely, its dysregulation also underlies multiple pathophysiologic processes. Regulation of vascular endothelial cell function requires the integration of complex signals via multiple cell types, including arterial smooth muscle, capillary and post-capillary pericytes, and other perivascular cells such as glial and immune cells. Here, we focus on the pericyte and its roles in microvascular remodeling, reviewing current concepts in microvascular pathophysiology and offering new insights into the specific roles that pericyte-dependent signaling pathways may play in modulating endothelial growth and microvascular tone during pathologic angiogenesis and essential hypertension.
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Affiliation(s)
- Matthew E Kutcher
- Department of Physiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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Abstract
Transforming growth factor-beta (TGF-beta)/bone morphogenic protein (BMP) signaling is involved in the vast majority of cellular processes and is fundamentally important during the entire life of all metazoans. Deregulation of TGF-beta/BMP activity almost invariably leads to developmental defects and/or diseases, including cancer. The proper functioning of the TGF-beta/BMP pathway depends on its constitutive and extensive communication with other signaling pathways, leading to synergistic or antagonistic effects and eventually desirable biological outcomes. The nature of such signaling cross-talk is overwhelmingly complex and highly context-dependent. Here we review the different modes of cross-talk between TGF-beta/BMP and the signaling pathways of Mitogen-activated protein kinase, phosphatidylinositol-3 kinase/Akt, Wnt, Hedgehog, Notch, and the interleukin/interferon-gamma/tumor necrosis factor-alpha cytokines, with an emphasis on the underlying molecular mechanisms.
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Affiliation(s)
- Xing Guo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Xiao-Fan Wang
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
Transforming growth factor-beta utilizes a multitude of intracellular signaling pathways in addition to Smads to regulate a wide array of cellular functions. These non-canonical, non-Smad pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. These non-Smad pathways include various branches of MAP kinase pathways, Rho-like GTPase signaling pathways, and phosphatidylinositol-3-kinase/AKT pathways. This review focuses on recent advances in the understanding of the molecular and biochemical mechanisms of non-Smad pathways. In addition, functions of these non-Smad pathways are also discussed.
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Affiliation(s)
- Ying E Zhang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Matsui H, Sakabe M, Sakata H, Yanagawa N, Ikeda K, Yamagishi T, Nakajima Y. Induction of initial heart α-actin, smooth muscle α-actin, in chick pregastrula epiblast: The role of hypoblast and fibroblast growth factor-8. Dev Growth Differ 2008; 50:143-57. [DOI: 10.1111/j.1440-169x.2008.00987.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Wrighton KH, Feng XH. To (TGF)beta or not to (TGF)beta: fine-tuning of Smad signaling via post-translational modifications. Cell Signal 2008; 20:1579-91. [PMID: 18387785 DOI: 10.1016/j.cellsig.2008.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 02/06/2008] [Indexed: 01/17/2023]
Abstract
Smad proteins are key signal transducers for the TGF-beta superfamily and are frequently inactivated in human cancers, yet the molecular basis of how their levels and activities are regulated remains unclear. Recent progress, discussed herein, illustrates the critical roles of Smad post-translational modifications in the cellular outcome to TGF-beta signaling.
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Affiliation(s)
- Katharine H Wrighton
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA
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Lee HJ, Ji Y, Paul S, Maehr H, Uskokovic M, Suh N. Activation of bone morphogenetic protein signaling by a Gemini vitamin D3 analogue is mediated by Ras/protein kinase C alpha. Cancer Res 2008; 67:11840-7. [PMID: 18089814 DOI: 10.1158/0008-5472.can-07-1549] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bone morphogenetic proteins (BMP) are members of the transforming growth factor-beta superfamily, and they play an important role for embryonic development, for bone and cartilage formation, and during carcinogenesis. We have previously shown that the novel Gemini vitamin D(3) analogue, Ro-438-3582 [Ro3582; 1 alpha,25-dihydroxy-20S,21(3-hydroxy-3-methylbutyl)-23-yne-26,27-hexafluorocholecalciferol], inhibited cell proliferation and activated the BMP/Smad signaling pathway in MCF10AT1 breast epithelial cells. In this report, we investigated the upstream signaling pathways responsible for the activation of BMP/Smad signaling by Ro3582. Among seven different serine/threonine kinase inhibitors that we tested, protein kinase C (PKC) inhibitors blocked the effects of Ro3582 on the phosphorylation of Smad1/5, mRNA synthesis for BMP-2 and BMP-6, and cell growth in MCF10AT1 cells. Overexpression of PKC alpha, but not PKC epsilon, PKC delta or PKC zeta isoforms, increased Ro3582-induced phosphorylation of Smad1/5, suggesting that PKC alpha mediates the activation of Smad signaling and inhibition of cell proliferation. Interestingly, the activation of Smad signaling by Ro3582 was shown in Ha-ras-transfected MCF10AT1 cells, but not in the parent cell line (MCF10A without Ras). Inhibiting Ras activity blocked the translocation of PKC alpha to the plasma membrane and the phosphorylation of Smad1/5 induced by Ro3582, indicating that Ras is necessary for the activation of PKC alpha and Smad signaling. In conclusion, Ro3582 inhibits cell proliferation and activates BMP/Smad signaling via a Ras and PKC alpha pathway in breast epithelial cells.
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Affiliation(s)
- Hong Jin Lee
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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Baugé C, Legendre F, Leclercq S, Elissalde JM, Pujol JP, Galéra P, Boumédiene K. Interleukin-1beta impairment of transforming growth factor beta1 signaling by down-regulation of transforming growth factor beta receptor type II and up-regulation of Smad7 in human articular chondrocytes. ACTA ACUST UNITED AC 2007; 56:3020-32. [PMID: 17763417 DOI: 10.1002/art.22840] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Extracellular matrix deposition is tightly controlled by a network of regulatory cytokines. Among them, interleukin-1beta (IL-1beta) and transforming growth factor beta1 (TGFbeta1) have been shown to play antagonistic roles in tissue homeostasis. The purpose of this study was to determine the influence of IL-1beta on TGFbeta receptor type II (TGFbetaRII) regulation and TGFbeta1 responsiveness in human articular chondrocytes. METHODS TGFbeta1-induced gene expression was analyzed through plasminogen activator inhibitor 1 and p3TP-Lux induction. Receptor-activated Smad (R-Smad) phosphorylation, TGFbeta receptors, and Smad expression were determined by Western blotting and real-time reverse transcription-polymerase chain reaction techniques. Signaling pathways were investigated using specific inhibitors, messenger RNA (mRNA) silencing, and expression vectors. RESULTS IL-1beta down-regulated TGFbetaRII expression at both the protein and mRNA levels and led to inhibition of the TGFbeta1-induced gene expression and Smad2/3 phosphorylation. Moreover, IL-1beta strongly stimulated the expression of inhibitory Smad7. TGFbetaRII overexpression abolished the loss of TGFbeta1 responsiveness induced by IL-1beta. The decrease in TGFbetaRII required de novo protein synthesis and involved both the NF-kappaB and JNK pathways. CONCLUSION We demonstrate that IL-1beta impairs TGFbeta1 signaling through down-regulation of TGFbetaRII, which is mediated by the p65/NF-kappaB and activator protein 1/JNK pathways, and secondarily through the up-regulation of Smad7. These findings show that there is cross-talk in the signaling of 2 regulatory cytokines involved in inflammation.
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Affiliation(s)
- C Baugé
- University of Caen Lower Normandy, Caen, France
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40
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Ross S, Hill CS. How the Smads regulate transcription. Int J Biochem Cell Biol 2007; 40:383-408. [PMID: 18061509 DOI: 10.1016/j.biocel.2007.09.006] [Citation(s) in RCA: 262] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 09/19/2007] [Accepted: 09/20/2007] [Indexed: 01/01/2023]
Abstract
The primary signalling pathway downstream of ligands of the transforming growth factor beta (TGF-beta) superfamily is the Smad pathway. Activated receptors phosphorylate receptor-regulated Smads, which form homomeric complexes and heteromeric complexes with Smad4. These activated Smad complexes accumulate in the nucleus, where they are directly involved in the regulation of transcription of target genes. This apparently very simple pathway is subject to complex regulation, much of which is at the level of post-translational modifications of pathway components, in particular, the Smads. The enzymes responsible may be constitutively active, may be cell type-specific or may be regulated by other signalling pathways or by the cell cycle. In this way, signals from TGF-beta superfamily ligands are integrated with signals from other growth factors and cytokines, are regulated by the cell cycle and are dependent on cell type. This may go some way to explaining the pleiotropic nature of TGF-beta superfamily responses. In this review we focus on the mechanisms whereby the Smads are modified and regulated. We then go on to discuss how the activated Smad complexes regulate transcription.
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Affiliation(s)
- Sarah Ross
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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Dai G, Vaughn S, Zhang Y, Wang ET, Garcia-Cardena G, Gimbrone MA. Biomechanical Forces in Atherosclerosis-Resistant Vascular Regions Regulate Endothelial Redox Balance via Phosphoinositol 3-Kinase/Akt-Dependent Activation of Nrf2. Circ Res 2007; 101:723-33. [PMID: 17673673 DOI: 10.1161/circresaha.107.152942] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Local patterns of biomechanical forces experienced by endothelial cells (ECs) in different vascular geometries appear to play an essential role in regulating EC function and determining the regional susceptibility to atherosclerosis, even in the face of systemic risk factors. To study how biomechanical forces regulate EC redox homeostasis, an important pathogenic factor in atherogenesis, we have cultured human ECs under 2 prototypic arterial shear stress waveforms, “atheroprone” and “atheroprotective,” which were derived from 2 distinct vascular regions in vivo that are typically “susceptible” or “resistant” to atherosclerosis. We demonstrate that atheroprotective flow decreases EC intracellular redox level and protects ECs against oxidative stress–induced injury. To identify the molecular mechanisms that control this cellular response, we examined several major oxidative/antioxidative pathways and found that atheroprotective flow upregulated certain antioxidant genes and strongly activated the transcription factor Nrf2. Using a strategy of small interfering RNA inhibition of Nrf2 expression combined with genome-wide transcriptional profiling, we determined the downstream targets of Nrf2 activation and identified Nrf2 as a critical determinant for the changes in endothelial redox balance exerted by atheroprotective flow. In addition, we showed that atheroprotective flow activates Nrf2 via the phosphoinositol 3-kinase/Akt pathway, and this activation occurs differentially in atherosclerosis-resistant and atherosclerosis-susceptible regions of the mouse aorta. Taken together, our data demonstrate that hemodynamic forces present in atherosclerosis-resistant and -susceptible regions of the vasculature differentially regulate EC redox state and antioxidant potential. These alterations in redox homeostasis are primarily the result of the phosphoinositol 3-kinase/Akt-dependent activation of Nrf2 and its downstream transcriptional targets.
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Affiliation(s)
- Guohao Dai
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass 02115-6110, USA
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Sekimoto G, Matsuzaki K, Yoshida K, Mori S, Murata M, Seki T, Matsui H, Fujisawa JI, Okazaki K. Reversible Smad-dependent signaling between tumor suppression and oncogenesis. Cancer Res 2007; 67:5090-6. [PMID: 17545585 DOI: 10.1158/0008-5472.can-06-4629] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cancer cells often gain advantage by reducing the tumor-suppressive activity of transforming growth factor-beta (TGF-beta) together with stimulation of its oncogenic activity as in Ras-transformed cells; however, molecular mechanisms remain largely unknown. TGF-beta activates both its type I receptor (TbetaRI) and c-Jun NH2-terminal kinase (JNK), which phosphorylate Smad2 and Smad3 at the COOH-terminal (pSmad2/3C) and linker regions (pSmad2/3L). Here, we report that Ras transformation suppresses TbetaRI-mediated pSmad3C signaling, which involves growth inhibition by down-regulating c-Myc. Instead, hyperactive Ras constitutively stimulates JNK-mediated pSmad2/3L signaling, which fosters tumor invasion by up-regulating plasminogen activator inhibitor-1 and matrix metalloproteinase-1 (MMP-1), MMP-2, and MMP-9. Conversely, selective blockade of linker phosphorylation by a mutant Smad3 lacking JNK-dependent phosphorylation sites results in preserved tumor-suppressive function via pSmad3C in Ras-transformed cells while eliminating pSmad2/3L-mediated invasive capacity. Thus, specific inhibition of the JNK/pSmad2/3L pathway should suppress cancer progression by shifting Smad-dependent signaling from oncogenesis to tumor suppression.
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Affiliation(s)
- Go Sekimoto
- Department of Gastroenterology, Kansai Medical University, Osaka, Japan
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Lee BH, Chen W, Stippec S, Cobb MH. Biological Cross-talk between WNK1 and the Transforming Growth Factor β-Smad Signaling Pathway. J Biol Chem 2007; 282:17985-17996. [PMID: 17392271 DOI: 10.1074/jbc.m702664200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WNKs (with no lysine (K)), unique serine/threonine protein kinases, have been best studied in the context of cell volume regulation and ion homeostasis. Here we describe a biological link between WNKs and transforming growth factor (TGF) beta-Smad signaling. Both WNK1 and WNK4 directly bind to and phosphorylate Smad2. Knockdown of WNK1 in HeLa cells using small interfering RNA reduces Smad2 protein expression; this decrease is at least partially due to down-regulation of Smad2 transcription. In contrast, phosphorylated Smad2 significantly accumulated in the nucleus as a consequence of depletion of WNK1, resulting in Smad-mediated transcriptional responses. In addition, TGFbeta-induced target gene transcripts were increased in WNK1 small interfering RNA cells. These findings suggest WNK1 as a dual modulator of TGFbeta-Smad signaling pathways.
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Affiliation(s)
- Byung-Hoon Lee
- Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9041
| | - Wei Chen
- Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9041
| | - Steve Stippec
- Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9041
| | - Melanie H Cobb
- Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9041.
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Lee J, Jung E, Lee J, Huh S, Kim J, Park M, So J, Ham Y, Jung K, Hyun CG, Kim YS, Park D. Panax ginseng induces human Type I collagen synthesis through activation of Smad signaling. JOURNAL OF ETHNOPHARMACOLOGY 2007; 109:29-34. [PMID: 16890388 DOI: 10.1016/j.jep.2006.06.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 06/15/2006] [Accepted: 06/24/2006] [Indexed: 05/11/2023]
Abstract
Skin aging appears to be principally related to a decrease in levels of Type I collagen, the primary component of the dermal layer of skin. It is important to introduce an efficient agent for effective management of skin aging; this agent should have the fewest possible side effects and the greatest wrinkle-reducing effect. In the course of screening collagen production-promoting agents, we obtained Panax ginseng C.A. Meyer. This study was designed to investigate the possible collagen production-promoting activities of Panax ginseng C.A. Meyer root extract (PGRE) in human dermal fibroblast cells. As a first step to this end, human COL1A2 promoter luciferase assay was performed in human dermal fibroblast cells. In this assay, PGRE activated human COL1A2 promoter activity in a concentration-dependent manner. Human Type I procollagen synthesis was also induced by PGRE. These results suggest that PGRE promotes collagen production in human dermal fibroblast cells. Additionally, we have attempted to characterize the mechanism of action of PGRE in Type I procollagen synthesis. PGRE was found to induce the phosphorylation of Smad2, an important transcription factor in the production of Type I procollagen. When applied topically in a human skin primary irritation test, PGRE did not induce any adverse reactions. Therefore, based on these results, we suggest the possibility that PGRE may be considered as an attractive, wrinkle-reducing candidate for topical application.
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Affiliation(s)
- Jongsung Lee
- Biospectrum Life Science Institute, 101-701 SK VENTIUM, 522 Dangjung Dong, Gunpo City, 435-833 Gyunggi Do, Republic of Korea
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Tanigawa T, Pai R, Arakawa T, Tarnawski AS. Rebamipide inhibits gastric cancer cell growth. Dig Dis Sci 2007; 52:240-7. [PMID: 17171453 DOI: 10.1007/s10620-006-9226-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 01/02/2006] [Indexed: 02/06/2023]
Abstract
Rebamipide is an antiulcer drug used in Japan, Korea, China, Philippines, and other Asian countries for treatment of gastritis and peptic ulcer. Its effect on gastric cancer cell growth and its regulatory mechanisms remain unknown. We examined whether rebamipide affects human gastric cancer cell proliferation and activation of Smad signaling pathway. Gastric cancer (AGS) cells were treated with either (a) medium (control), (b) medium-containing rebamipide (0.5-2 mg/mL), or (c) PD98059+rebamipide. We determined cell proliferation, expression of p21, phosphorylation of ERK2, JNK p38, and Smad2/3, formation of Smad2/3-Smad4 complex, and nuclear translocation of Smad2/3. Rebamipide treatment inhibited AGS cell proliferation and increased p21, Smad2/3 phosphorylation, and Smad2/3-Smad4 complex formation. Rebamipide induced phosphorylation of ERK2 but not JNK or p38. Inactivation of ERK2 by PD98059 partly attenuated rebamipide-induced p21 expression. These data demonstrate that rebamipide activates Smad signaling pathway and suppresses human gastric cancer cell growth. Inactivation of ERK2 partly inhibited rebamipide-induced p21 expression, indicating a crosstalk between ERK and Smad signaling pathways.
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Affiliation(s)
- Tetsuya Tanigawa
- Medical Service, Department of Veterans Affairs Medical Center, Long Beach, California 90822, USA
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Leivonen SK, Kähäri VM. Transforming growth factor-β signaling in cancer invasion and metastasis. Int J Cancer 2007; 121:2119-24. [PMID: 17849476 DOI: 10.1002/ijc.23113] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Transforming growth factor-beta (TGF-beta) family members are polypeptides with dual tumor suppressive and oncogenic effects. They signal through serine/threonine kinase receptor complexes, which phosphorylate cytoplasmic mediators, the Smads. Upon phosphorylation, Smads translocate to the nucleus and associate with transcriptional coactivators or corepressors, and regulate the transcriptional activation of various TGF-beta responsive genes. In addition, TGF-beta activates cellular mitogen-activated protein kinase signaling pathways, which crosstalk with Smad signaling and regulate growth, survival and motility of cells. During tumorigenesis, malignantly transformed cells often lose the response to the tumor suppressive effects of TGF-beta, which, in turn, starts to act as an autocrine tumor promoting factor by enhancing cancer invasion and metastasis. In this review, we summarize current view on the role of TGF-beta signaling in tumorigenesis, with emphasis on cancer invasion and metastasis. On the basis of these recent observations, we discuss new therapeutic strategies targeting TGF-beta signaling at distinct levels as a basis for inhibiting tumor growth, angiogenesis, invasion and metastasis.
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Li J, Campanale NV, Liang RJ, Deane JA, Bertram JF, Ricardo SD. Inhibition of p38 mitogen-activated protein kinase and transforming growth factor-beta1/Smad signaling pathways modulates the development of fibrosis in adriamycin-induced nephropathy. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:1527-40. [PMID: 17071578 PMCID: PMC1780196 DOI: 10.2353/ajpath.2006.060169] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inflammation and fibrogenesis are the two determinants of the progression of renal fibrosis, the common pathway leading to end-stage renal disease. The p38 mitogen-activated protein kinase (MAPK) and transforming growth factor (TGF)-beta1/Smad signaling pathways play critical roles in inflammation and fibrogenesis, respectively. The present study examined the beneficial renoprotective effect of combination therapy using the p38 MAPK pathway inhibitor (SB203580) and a TGF-beta receptor I (ALK5) inhibitor (ALK5I) in a mouse model of adriamycin (ADR) nephrosis. The p38 MAPK and TGF-beta1/Smad2 signaling pathways were activated in ADR-induced nephropathy in a sequential time course manner. Two weeks after ADR injection, the combined administration of SB203580 (1 mg/kg/24 hours) and ALK5I (1 mg/kg/24 hours) markedly reduced p38 MAPK and Smad2 activities. Moreover, the co-administration of SB203580 and ALK5I to ADR-injected mice resulted in a down-regulation of total and active TGF-beta1 production, reduced myofibroblast accumulation, and decreased expression of collagen type IV and fibronectin. In these mice, retardation in the development of glomerulosclerosis and interstitial fibrosis was observed. In conclusion, although p38 MAPK and TGF-beta1/Smad signaling pathways are distinct they coordinate the progression of renal fibrosis in ADR nephrosis. The co-administration of a p38 MAPK inhibitor and an ALK5 inhibitor may have potential applications in the treatment of renal fibrosis.
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Affiliation(s)
- Jinhua Li
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria 3800, Australia
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Wrighton KH, Willis D, Long J, Liu F, Lin X, Feng XH. Small C-terminal domain phosphatases dephosphorylate the regulatory linker regions of Smad2 and Smad3 to enhance transforming growth factor-beta signaling. J Biol Chem 2006; 281:38365-75. [PMID: 17035229 DOI: 10.1074/jbc.m607246200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) controls a diverse set of cellular processes, and its canonical signaling is mediated via TGF-beta-induced phosphorylation of receptor-activated Smads (2 and 3) at the C-terminal SXS motif. We recently discovered that PPM1A can dephosphorylate Smad2/3 at the C-terminal SXS motif, implicating a critical role for phosphatases in regulating TGF-beta signaling. Smad2/3 activity is also regulated by phosphorylation in the linker region (and N terminus) by a variety of intracellular kinases, making it a critical platform for cross-talk between TGF-beta and other signaling pathways. Using a functional genomic approach, we identified the small C-terminal domain phosphatase 1 (SCP1) as a specific phosphatase for Smad2/3 dephosphorylation in the linker and N terminus. A catalytically inactive SCP1 mutant (dnSCP1) had no effect on Smad2/3 phosphorylation in vitro or in vivo. Of the other FCP/SCP family members SCP2 and SCP3, but not FCP1, could also dephosphorylate Smad2/3 in the linker/N terminus. Depletion of SCP1/2/3 enhanced Smad2/3 linker phosphorylation. SCP1 increased TGF-beta-induced transcriptional activity in agreement with the idea that phosphorylation in the Smad2/3 linker must be removed for a full transcriptional response. SCP1 overexpression also counteracts the inhibitory effect of epidermal growth factor on TGF-beta-induced p15 expression. Taken together, this work identifies the first example of a Smad2/3 linker phosphatase(s) and reveals an important new substrate for SCPs.
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Affiliation(s)
- Katharine H Wrighton
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Kuang PP, Joyce-Brady M, Zhang XH, Jean JC, Goldstein RH. Fibulin-5 gene expression in human lung fibroblasts is regulated by TGF-beta and phosphatidylinositol 3-kinase activity. Am J Physiol Cell Physiol 2006; 291:C1412-21. [PMID: 16837650 DOI: 10.1152/ajpcell.00087.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Fibulin-5 (FBLN5), an extracellular matrix glycoprotein required for normal elastogenesis, is coordinately expressed with elastin during lung injury and repair. We found that treatment with transforming growth factor-beta (TGF-beta) induced a rapid but transient increase in FBLN5 heterogeneous nuclear RNA (hnRNA) followed by a sustained increased in the steady-state level of FBLN5 mRNA. The transcription start site of the human FBLN5 gene was localized at 221 nucleotides upstream of the translation start site by using primer extension, Northern blots, and functional analysis of transcriptional activity in reporter plasmids containing 5'-flanking regions. TGF-beta markedly increased FBLN5 promoter activity in transient transfection assays. Two putative Smad-binding sites were identified within the proximal promoter and are required for this TGF-beta induction. Electrophoretic gel mobility shift assay revealed that TGF-beta strongly increased binding of Smad2 and Smad3 nuclear complexes to the proximal FBLN5 promoter and induced a Smad2/3-dependent binding of slow migrating nuclear protein complex. FBLN5 mRNA induction by TGF-beta was blocked by pretreatment with TGF-beta receptor inhibitor SB-431542, the phosphatidylinositol 3-kinase (PI3-kinase) inhibitor LY-294002, and actinomycin D. Basal and TGF-beta-induced FBLN5 hnRNA and mRNA were strongly and proportionally decreased by LY-294002, as was TGF-beta-induced phosphorylation of Akt, but not Smad3, as measured by Western blot analysis. In addition, LY-294002 markedly and proportionally decreased FBLN5 promoter activity in transient transfection analyses with TGF-beta-treated or untreated lung fibroblasts. These studies demonstrate that induction of FBLN5 gene expression in lung fibroblasts is mediated via canonical TGF-beta/Smad signaling and requires the PI3-kinase/Akt pathway.
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Affiliation(s)
- Ping-Ping Kuang
- The Pulmonary Center and Department of Biochemistry, Boston University School of Medicine, Boston Veteran Administration Medical Center, Boston, Massachusetts 02118, USA.
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