1
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Alnimer A, Bhamidimarri PM, Talaat IM, Alkhayaal N, Eltayeb A, Ali N, Abusnana S, Hamoudi R, Bendardaf R. Association Between Expression of Vitamin D Receptor and Insulin-Like Growth Factor 1 Receptor Among Breast Cancer Patients. World J Oncol 2023; 14:67-74. [PMID: 36895995 PMCID: PMC9990736 DOI: 10.14740/wjon1550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 12/30/2022] [Indexed: 03/01/2023] Open
Abstract
Background Vitamin D receptor (VDR) and insulin-like growth factor 1 receptor (IGF1R) are known to be involved in breast cancer (BC) progression. Our previous work reported a correlation of differential localization of IGF1R with hormone receptor status in BC. A recent report described VDR and IGF1R as potential indicators of BC prognosis, but their interplay was not discussed. The present study focused on understanding the association of VDR expression with IGF1R activation, different molecular markers, and subtypes of BC. Methods A retrospective study was designed to evaluate the VDR expression among 48 BC patients pathologically diagnosed as invasive BC and were surgically treated at Sharjah Breast Care Center, University Hospital Sharjah (UHS), United Arab Emirates (UAE). Formalin-fixed paraffin-embedded (FFPE) tumor blocks with appropriate clinicopathological data were subjected to immunohistochemistry (IHC), and VDR protein expression was interpreted based on the staining intensity (SI) and the percentage of the positively stained cells (PP). Results Nearly 44% of cases in the study were vitamin D deficient. A positive VDR expression with strong intensity (score > 4) was seen in 27 cases (56.3%). The expression pattern for VDR was equally distributed in cytoplasm and nucleus. For the IGF1R intensity, 24 cases (50%) of total cohort showed strong expression. A significant association was detected between IGF1R and VDR expression (P = 0.031). Conclusions The present study identified positive association between IGF1R and VDR expression where most of the cases with strong VDR expression displayed strong IGF1R expression. These findings may contribute to current understanding on the role of VDR in BC and its interaction with IGF1R.
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Affiliation(s)
- Ayaa Alnimer
- College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,These authors contributed equally to the study
| | - Poorna Manasa Bhamidimarri
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,These authors contributed equally to the study
| | - Iman M Talaat
- College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Noura Alkhayaal
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,University Hospital Sharjah, Sharjah, United Arab Emirates
| | - Abdalla Eltayeb
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Nival Ali
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Salah Abusnana
- College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,University Hospital Sharjah, Sharjah, United Arab Emirates
| | - Rifat Hamoudi
- College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Division of Surgery and Interventional Science, University College London, London, UK
| | - Riyad Bendardaf
- College of Medicine, University of Sharjah, Sharjah, United Arab Emirates.,University Hospital Sharjah, Sharjah, United Arab Emirates.,Department of Oncology, University Hospital Sharjah, Sharjah, United Arab Emirates
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2
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Horas K, Abraham M, Ebert R, Weissenberger M, Maier GS, Jakob F, Rosenwald A, Rudert M. Vitamin D Receptor Expression Is Significantly Decreased in Bone Metastases Compared to Matched Primary Breast Cancer Tumours. Cancer Invest 2023; 41:133-143. [PMID: 36314889 DOI: 10.1080/07357907.2022.2142604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
There is ample evidence today that vitamin D signalling via the vitamin D receptor (VDR) plays a pivotal role in cancer growth and metastasis. The aim of this study was to analyse VDR expression of primary breast cancer and corresponding bone metastases tissue samples. Collectively, 15 sample pairs and 11 samples of patients that did not develop metastases were analysed histologically for VDR expression (n = 41). Overall, VDR expression was significantly lower in bone metastases compared to primary tumour samples (p < .0001). Downregulation of the VDR in breast cancer cells may define a critical turning point in oncogenesis that accelerates cancer cell dissemination and metastases.
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Affiliation(s)
- Konstantin Horas
- Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, Wuerzburg, Germany.,Bernhard-Heine Centre for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Marc Abraham
- Bernhard-Heine Centre for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Regina Ebert
- Bernhard-Heine Centre for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Manuel Weissenberger
- Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, Wuerzburg, Germany
| | - Gerrit S Maier
- Department of Orthopaedic Surgery, Pius-Hospital, Carl-von-Ossietzky-University, Oldenburg, Germany
| | - Franz Jakob
- Bernhard-Heine Centre for Locomotion Research, University of Wuerzburg, Wuerzburg, Germany
| | - Andreas Rosenwald
- Department of Pathology, University of Wuerzburg, Wuerzburg, Germany
| | - Maximilian Rudert
- Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, Wuerzburg, Germany
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3
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Yuzawa R, Koike H, Manabe I, Oishi Y. VDR regulates simulated microgravity-induced atrophy in C2C12 myotubes. Sci Rep 2022; 12:1377. [PMID: 35082348 PMCID: PMC8791983 DOI: 10.1038/s41598-022-05354-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 01/10/2022] [Indexed: 11/30/2022] Open
Abstract
Muscle wasting is a major problem leading to reduced quality of life and higher risks of mortality and various diseases. Muscle atrophy is caused by multiple conditions in which protein degradation exceeds its synthesis, including disuse, malnutrition, and microgravity. While Vitamin D receptor (VDR) is well known to regulate calcium and phosphate metabolism to maintain bone, recent studies have shown that VDR also plays roles in skeletal muscle development and homeostasis. Moreover, its expression is upregulated in muscle undergoing atrophy as well as after muscle injury. Here we show that VDR regulates simulated microgravity-induced atrophy in C2C12 myotubes in vitro. After 8 h of microgravity simulated using 3D-clinorotation, the VDR-binding motif was associated with chromatin regions closed by the simulated microgravity and enhancer regions inactivated by it, which suggests VDR mediates repression of enhancers. In addition, VDR was induced and translocated into the nuclei in response to simulated microgravity. VDR-deficient C2C12 myotubes showed resistance to simulated microgravity-induced atrophy and reduced induction of FBXO32, an atrophy-associated ubiquitin ligase. These results demonstrate that VDR contributes to the regulation of simulated microgravity-induced atrophy at least in part by controlling expression of atrophy-related genes.
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4
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Sneha S, Baker SC, Green A, Storr S, Aiyappa R, Martin S, Pors K. Intratumoural Cytochrome P450 Expression in Breast Cancer: Impact on Standard of Care Treatment and New Efforts to Develop Tumour-Selective Therapies. Biomedicines 2021; 9:biomedicines9030290. [PMID: 33809117 PMCID: PMC7998590 DOI: 10.3390/biomedicines9030290] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/05/2021] [Accepted: 03/07/2021] [Indexed: 12/13/2022] Open
Abstract
Despite significant advances in treatment strategies over the past decade, selective treatment of breast cancer with limited side-effects still remains a great challenge. The cytochrome P450 (CYP) family of enzymes contribute to cancer cell proliferation, cell signaling and drug metabolism with implications for treatment outcomes. A clearer understanding of CYP expression is important in the pathogenesis of breast cancer as several isoforms play critical roles in metabolising steroid hormones and xenobiotics that contribute to the genesis of breast cancer. The purpose of this review is to provide an update on how the presence of CYPs impacts on standard of care (SoC) drugs used to treat breast cancer as well as discuss opportunities to exploit CYP expression for therapeutic intervention. Finally, we provide our thoughts on future work in CYP research with the aim of supporting ongoing efforts to develop drugs with improved therapeutic index for patient benefit.
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Affiliation(s)
- Smarakan Sneha
- Institute of Cancer Therapeutics, School of Pharmacy and Medical Sciences, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK;
| | - Simon C. Baker
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology & York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK;
| | - Andrew Green
- Nottingham Breast Cancer Research Centre, School of Medicine, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK; (A.G.); (S.S.); (R.A.); (S.M.)
| | - Sarah Storr
- Nottingham Breast Cancer Research Centre, School of Medicine, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK; (A.G.); (S.S.); (R.A.); (S.M.)
| | - Radhika Aiyappa
- Nottingham Breast Cancer Research Centre, School of Medicine, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK; (A.G.); (S.S.); (R.A.); (S.M.)
| | - Stewart Martin
- Nottingham Breast Cancer Research Centre, School of Medicine, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK; (A.G.); (S.S.); (R.A.); (S.M.)
| | - Klaus Pors
- Institute of Cancer Therapeutics, School of Pharmacy and Medical Sciences, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK;
- Correspondence: ; Tel.: +44-(0)1274-236482 or +44-(0)1274-235866; Fax: +44-(0)1274-233234
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5
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Ali AA, Cui X, Pertile RAN, Li X, Medley G, Alexander SA, Whitehouse AJO, McGrath JJ, Eyles DW. Developmental vitamin D deficiency increases foetal exposure to testosterone. Mol Autism 2020; 11:96. [PMID: 33298169 PMCID: PMC7727109 DOI: 10.1186/s13229-020-00399-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/06/2020] [Indexed: 12/18/2022] Open
Abstract
Background Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders which are more common in males. The ‘prenatal sex steroid’ hypothesis links excessive sex-steroid exposure during foetal life with the behavioural differences observed in ASD. However, the reason why sex steroid exposure may be excessive remains unclear. Epidemiological studies have identified several environmental risk factors associated with ASD, including developmental vitamin D (DVD) deficiency. We have demonstrated in an animal model that DVD-deficiency is associated with a hyper-inflammatory response in placentas from male but not female foetuses. Vitamin D also regulates the expression of several steroidogenic enzymes in vitro. Therefore using this animal model, we have examined whether DVD-deficiency leads to increased sex-steroid levels in both the maternal and foetal compartments. Methods Female rats are fed a vitamin D deficient diet from 6 weeks before mating until tissue collection at embryonic day 18. We examined the levels of testosterone, androstenedione and corticosterone in maternal plasma, foetal brains and amniotic fluid. We further examined gene expressions of steroidogenic enzymes and DNA methylation of aromatase promoters in foetal brains as a potential molecular mechanism regulating testosterone expression. Results We show that DVD-deficiency increases testosterone levels in maternal blood. We also show elevated levels of testosterone and androstenedione in the amniotic fluid of female but not male DVD-deficient foetuses. Testosterone levels were also elevated in DVD-deficient male brains. Vitamin D, like other steroid-related hormones, regulates gene expression via methylation. Therefore we examined whether the significant elevation in testosterone in male brains was due to such a potential gene-silencing mechanism. We show that the promoter of aromatase was hyper-methylated compared to male controls. Limitations A reduction in aromatase, in addition to causing excessive testosterone, could also lead to a reduction in estradiol which was not examined here. Conclusions This study is the first to show how an epidemiologically established environmental risk factor for ASD may selectively elevate testosterone in male embryonic brains. These findings provide further mechanistic support for the prenatal sex steroid theory of ASD.
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Affiliation(s)
- Asad Amanat Ali
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Xiaoying Cui
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
| | | | - Xiang Li
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Gregory Medley
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Suzanne Adele Alexander
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
| | - Andrew J O Whitehouse
- Telethon Kids Institute, The University of Western Australia, Perth, WA, 6009, Australia
| | - John Joseph McGrath
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia.,NCRR-National Centre for Register-Based Research, Department of Economics and Business Economics, Aarhus University, Aarhus C, Denmark
| | - Darryl Walter Eyles
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia. .,Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia.
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6
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Yao X, Wang Z, El-Samahy MA, Ren C, Liu Z, Wang F, You P. Roles of vitamin D and its receptor in the proliferation and apoptosis of luteinised granulosa cells in the goat. Reprod Fertil Dev 2020; 32:335-348. [DOI: 10.1071/rd18442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 06/16/2019] [Indexed: 12/27/2022] Open
Abstract
The objective of this study was to investigate the dose-dependent effect of 1α,25-(OH)2VD3 (Vit D3) on invitro proliferation of goat luteinised granulosa cells (LGCs) and to determine the underlying mechanisms of its action by overexpressing and silencing vitamin D receptor (VDR) in LGCs. Results showed that VDR was prominently localised in GCs and theca cells (TCs) and its expression increased with follicle diameter, but was lower in atretic follicles than in healthy follicles. The proliferation rate of LGCs was significantly higher in the Vit D3-treated groups than in the control group, with the highest proliferation rate observed in the 10nM group; this was accompanied by changes in the expression of cell cycle-related genes. These data indicate that Vit D3 affects LGC proliferation in a dose-dependent manner. Contrary to the VDR knockdown effects, its overexpression upregulated and downregulated cell cycle- and apoptosis-related genes respectively; moreover, supplementation with 10nM of Vit D3 significantly enhanced these effects. These results suggest that changes in VDR expression patterns in LGCs may be associated with follicular development by regulation of cell proliferation and apoptosis. These findings will enhance the understanding of the roles of Vit D3 and VDR in goat ovarian follicular development.
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7
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Costa PLF, França MM, Katayama ML, Carneiro ET, Martin RM, Folgueira MAK, Latronico AC, Ferraz-de-Souza B. Transcriptomic Response to 1,25-Dihydroxyvitamin D in Human Fibroblasts with or without a Functional Vitamin D Receptor (VDR): Novel Target Genes and Insights into VDR Basal Transcriptional Activity. Cells 2019; 8:cells8040318. [PMID: 30959822 PMCID: PMC6523947 DOI: 10.3390/cells8040318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/29/2019] [Accepted: 04/03/2019] [Indexed: 01/30/2023] Open
Abstract
The vitamin D receptor (VDR) mediates vitamin D actions beyond bone health. While VDR activation by 1,25-dihydroxyvitamin D (1,25D) leads to robust transcriptional regulation, less is known about VDR actions in the absence of 1,25D. We analyzed the transcriptomic response to 1,25D in fibroblasts bearing a severe homozygous hereditary vitamin D resistant rickets-related p.Arg30* VDR mutation (MUT) and in control fibroblasts (CO). Roughly 4.5% of the transcriptome was regulated by 1,25D in CO fibroblasts, while MUT cells without a functional VDR were insensitive to 1,25D. Novel VDR target genes identified in human fibroblasts included bone and cartilage factors CILP, EFNB2, and GALNT12. Vehicle-treated CO and MUT fibroblasts had strikingly different transcriptomes, suggesting basal VDR activity. Indeed, oppositional transcriptional effects in basal conditions versus after 1,25D activation were implied for a subset of target genes mostly involved with cell cycle. Cell proliferation assays corroborated this conjectured oppositional basal VDR activity, indicating that precise 1,25D dosage in target tissues might be essential for modulating vitamin D actions in human health.
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Affiliation(s)
- Pedro L F Costa
- Laboratorio de Endocrinologia Celular e Molecular LIM-25 e Unidade de Doencas Osteometabolicas, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 01246-903, SP, Brazil.
| | - Monica M França
- Laboratorio de Endocrinologia Celular e Molecular LIM-25 e Unidade de Doencas Osteometabolicas, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 01246-903, SP, Brazil.
- Laboratorio de Hormonios e Genetica Molecular LIM-42, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 05403-900, SP, Brazil.
| | - Maria L Katayama
- Departamento de Radiologia e Oncologia, Instituto do Cancer do Estado de Sao Paulo (ICESP), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo 01246-000, SP, Brazil.
| | - Eduardo T Carneiro
- Laboratorio de Endocrinologia Celular e Molecular LIM-25 e Unidade de Doencas Osteometabolicas, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 01246-903, SP, Brazil.
| | - Regina M Martin
- Laboratorio de Hormonios e Genetica Molecular LIM-42, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 05403-900, SP, Brazil.
| | - Maria A K Folgueira
- Departamento de Radiologia e Oncologia, Instituto do Cancer do Estado de Sao Paulo (ICESP), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo 01246-000, SP, Brazil.
| | - Ana C Latronico
- Laboratorio de Hormonios e Genetica Molecular LIM-42, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 05403-900, SP, Brazil.
| | - Bruno Ferraz-de-Souza
- Laboratorio de Endocrinologia Celular e Molecular LIM-25 e Unidade de Doencas Osteometabolicas, Divisao de Endocrinologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo 01246-903, SP, Brazil.
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8
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Ricca C, Aillon A, Bergandi L, Alotto D, Castagnoli C, Silvagno F. Vitamin D Receptor Is Necessary for Mitochondrial Function and Cell Health. Int J Mol Sci 2018; 19:ijms19061672. [PMID: 29874855 PMCID: PMC6032156 DOI: 10.3390/ijms19061672] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/03/2018] [Accepted: 06/03/2018] [Indexed: 01/09/2023] Open
Abstract
Vitamin D receptor (VDR) mediates many genomic and non-genomic effects of vitamin D. Recently, the mitochondrial effects of vitamin D have been characterized in many cell types. In this article, we investigated the importance of VDR not only in mitochondrial activity and integrity but also in cell health. The silencing of the receptor in different healthy, non-transformed, and cancer cells initially decreased cell growth and modulated the cell cycle. We demonstrated that, in silenced cells, the increased respiratory activity was associated with elevated reactive oxygen species (ROS) production. In the long run, the absence of the receptor caused impairment of mitochondrial integrity and, finally, cell death. Our data reveal that VDR plays a central role in protecting cells from excessive respiration and production of ROS that leads to cell damage. Because we confirmed our observations in different models of both normal and cancer cells, we conclude that VDR is essential for the health of human tissues.
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Affiliation(s)
- Chiara Ricca
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
| | - Alessia Aillon
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
| | - Loredana Bergandi
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
| | - Daniela Alotto
- Department of Chirurgia Generale e Specialistiche, Banca della Cute, AOU Città della Salute e della Scienza Torino, Via Zuretti 29, 10126 Torino, Italy.
| | - Carlotta Castagnoli
- Department of Chirurgia Generale e Specialistiche, Banca della Cute, AOU Città della Salute e della Scienza Torino, Via Zuretti 29, 10126 Torino, Italy.
| | - Francesca Silvagno
- Department of Oncology, University of Torino, Via Santena 5 bis, 10126 Torino, Italy.
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9
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Trivedi T, Zheng Y, Fournier PGJ, Murthy S, John S, Schillo S, Dunstan CR, Mohammad KS, Zhou H, Seibel MJ, Guise TA. The vitamin D receptor is involved in the regulation of human breast cancer cell growth via a ligand-independent function in cytoplasm. Oncotarget 2018; 8:26687-26701. [PMID: 28460457 PMCID: PMC5432290 DOI: 10.18632/oncotarget.15803] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/15/2017] [Indexed: 12/31/2022] Open
Abstract
Vitamin D has pleiotropic effects on multiple tissues, including malignant tumors. Vitamin D inhibits breast cancer growth through activation of the vitamin D receptor (VDR) and via classical nuclear signaling pathways. Here, we demonstrate that the VDR can also function in the absence of its ligand to control behaviour of human breast cancer cells both outside and within the bone microenvironment. Stable shRNA expression was used to knock down VDR expression in MCF-7 cells, generating two VDR knockdown clonal lines. In ligand-free culture, knockdown of VDR in MCF-7 cells significantly reduced proliferation and increased apoptosis, suggesting that the VDR plays a ligand-independent role in cancer cell growth. Implantation of these VDR knockdown cells into the mammary fat pad of nude mice resulted in reduced tumor growth in vivo compared with controls. In the intra-tibial xenograft model, VDR knockdown greatly reduced the ability of the cells to form tumors in the bone microenvironment. The in vitro growth of VDR knockdown cells was rescued by the expression of a mutant form of VDR which is unable to translocate to the nucleus and hence accumulates in the cytoplasm. Thus, our data indicate that in the absence of ligand, the VDR promotes breast cancer growth both in vitro and in vivo and that cytoplasmic accumulation of VDR is sufficient to produce this effect in vitro. This new mechanism of VDR action in breast cancer cells contrasts the known anti-proliferative nuclear actions of the VDR-vitamin D ligand complex.
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Affiliation(s)
- Trupti Trivedi
- Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia.,Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
| | - Yu Zheng
- Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Pierrick G J Fournier
- Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA.,Biomedical Innovation Department, Scientific Research and High Education Center from Ensenada (CICESE), Ensenada, Baja California, Mexico
| | - Sreemala Murthy
- Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
| | - Sutha John
- Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
| | - Suzanne Schillo
- Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Colin R Dunstan
- Department of Biomedical Engineering, University of Sydney, Sydney, Australia
| | - Khalid S Mohammad
- Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
| | - Hong Zhou
- Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia
| | - Markus J Seibel
- Bone Research Program, ANZAC Research Institute, University of Sydney, Sydney, Australia.,Department of Endocrinology and Metabolism, Concord Hospital, Concord, Sydney, Australia
| | - Theresa A Guise
- Division of Endocrinology, Department of Medicine, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
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10
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Abstract
Triple negative breast cancer (TNBC) has been associated with the lack of three hormone receptors; estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). However, a host of other steroid hormone receptors such as vitamin D receptor (VDR) is present in TNBC, and the role of these hormone receptors in breast tumorigenesis is unclear. The levels of microRNAs (miRNAs) are also expressed differently than in normal mammary epithelial cells. miRNAs are regulatory RNAs involved in various cellular functions, mainly gene silencing. Here, we reviewed the literature surrounding miRNAs in breast cancer, and performed in silico analysis to determine whether there was a correlation between levels of VDR in relation to miRNAs important in breast cancer development and tumorigenesis. We identified three miRNAs of interest, specifically, miR-23, miR-124, and miR-125. Through this research we determined the possibility that these miRNAs play an important role in controlling VDR activity and by virtue the development of breast cancer.
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Affiliation(s)
- Tatyana Singh
- a State University of New York - University at Albany , Albany , NY , USA
| | - Brian D Adams
- a State University of New York - University at Albany , Albany , NY , USA.,b Department of Internal Medicine , Yale University School of Medicine , New Haven , CT , USA.,c The RNA Institute , State University of New York - University at Albany , Albany , NY , USA
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11
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Yoshida S, Ikeda Y, Aihara KI. Roles of the Androgen – Androgen Receptor System in Vascular Angiogenesis. J Atheroscler Thromb 2016; 23:257-65. [DOI: 10.5551/jat.31047] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Sumiko Yoshida
- Department of Hematology, Endocrinology and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Yasumasa Ikeda
- Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Ken-ichi Aihara
- Department of Hematology, Endocrinology and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School
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12
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Ahn J, Park S, Zuniga B, Bera A, Song CS, Chatterjee B. Vitamin D in Prostate Cancer. VITAMINS AND HORMONES 2015; 100:321-55. [PMID: 26827958 DOI: 10.1016/bs.vh.2015.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Metastatic castration-resistant prostate cancer (mCRPC) is a progressive, noncurable disease induced by androgen receptor (AR) upon its activation by tumor tissue androgen, which is generated from adrenal steroid dehydroepiandrosterone (DHEA) through intracrine androgen biosynthesis. Inhibition of mCRPC and early-stage, androgen-dependent prostate cancer by calcitriol, the bioactive vitamin D3 metabolite, is amply documented in cell culture and animal studies. However, clinical trials of calcitriol or synthetic analogs are inconclusive, although encouraging results have recently emerged from pilot studies showing efficacy of a safe-dose vitamin D3 supplementation in reducing tumor tissue inflammation and progression of low-grade prostate cancer. Vitamin D-mediated inhibition of normal and malignant prostate cells is caused by diverse mechanisms including G1/S cell cycle arrest, apoptosis, prodifferentiation gene expression changes, and suppressed angiogenesis and cell migration. Biological effects of vitamin D are mediated by altered expression of a gene network regulated by the vitamin D receptor (VDR), which is a multidomain, ligand-inducible transcription factor similar to AR and other nuclear receptors. AR-VDR cross talk modulates androgen metabolism in prostate cancer cells. Androgen inhibits vitamin D-mediated induction of CYP24A1, the calcitriol-degrading enzyme, while vitamin D promotes androgen inactivation by inducing phase I monooxygenases (e.g., CYP3A4) and phase II transferases (e.g., SULT2B1b, a DHEA-sulfotransferase). CYP3A4 and SULT2B1b levels are markedly reduced and CYP24A1 is overexpressed in advanced prostate cancer. In future trials, combining low-calcemic, potent next-generation calcitriol analogs with CYP24A1 inhibition or androgen supplementation, or cancer stem cell suppression by a phytonutrient such as sulfarophane, may prove fruitful in prostate cancer prevention and treatment.
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Affiliation(s)
- Jungmi Ahn
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA
| | - Sulgi Park
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA
| | - Baltazar Zuniga
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA; The University of Texas at Austin, Austin, Texas, USA
| | - Alakesh Bera
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA
| | - Chung Seog Song
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA
| | - Bandana Chatterjee
- Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, Texas Research Park, San Antonio, Texas, USA; South Texas Veterans Health Care System, Audie L Murphy VA Hospital, San Antonio, Texas, USA.
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13
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Vitamin D Analogs Potentiate the Antitumor Effect of Imatinib Mesylate in a Human A549 Lung Tumor Model. Int J Mol Sci 2015; 16:27191-207. [PMID: 26580599 PMCID: PMC4661874 DOI: 10.3390/ijms161126016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 10/22/2015] [Accepted: 11/02/2015] [Indexed: 12/29/2022] Open
Abstract
In previous papers, we presented data on studies on the anticancer activity of the vitamin D3 analogs, named PRI-2191 and PRI-2205, in different cancer models. In this study, we showed the improved antiproliferative activity of a combination of imatinib mesylate (Gleevec, GV) and cytostatic agents in in vitro studies, when used with a third compound, namely PRI-2191, in an A549 human lung cancer model. Furthermore, we analyzed the influence of both PRI-2191, as well as PRI-2205 on the anticancer activity of GV in mice bearing A549 tumors. The route of PRI-2191 analog administration showed a significant impact on the outcome of GV treatment: subcutaneous injection was more efficient and less toxic than oral gavage. Moreover, both vitamin D compounds increased the anticancer activity of GV; however, they might also potentiate some adverse effects. We also evaluated in tumor tissue the expression of VEGF, PDGF-BB, vitamin D receptor, CYP27B1, CYP24, p53 and Bcl-2, as well as PDGF receptors: α and β. We observed the upregulation of p53 expression and the downregulation of Bcl-2, as well as VEGF in A549 tumors as a result of the tested treatment. However, vitamin D analogs did not significantly influence the expression of these proteins.
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14
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Singh T, Ayasolla K, Rai P, Chandel N, Haque S, Lederman R, Husain M, Vethantham V, Chawla A, Vashistha H, Saleem MA, Ding G, Chander PN, Malhotra A, Meggs LG, Singhal PC. AT1R blockade in adverse milieus: role of SMRT and corepressor complexes. Am J Physiol Renal Physiol 2015; 309:F189-203. [PMID: 26084932 DOI: 10.1152/ajprenal.00476.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 06/11/2015] [Indexed: 12/31/2022] Open
Abstract
ANG II type 1 receptor blockade (AT1R-BLK) is used extensively to slow down the progression of proteinuric kidney diseases. We hypothesized that AT1R-BLK provides podocyte protection through regulation of silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) and vitamin D receptor (VDR) expression under adverse milieus such as high glucose and human immunodeficiency virus infection. Both AT1R-BLK and VDR agonists (VDAs) stimulated VDR complex formation that differed not only in their composition but also in their functionality. AT1R-BLK-induced VDR complexes contained predominantly unliganded VDR, SMRT, and phosphorylated histone deacetylase 3, whereas VDA-VDR complexes were constituted by liganded VDR and CREB-binding protein/p300. AT1R-BLK-induced complexes attenuated podocyte acetyl-histone 3 levels as well as cytochrome P-450 family 24A1 expression, thus indicating their deacetylating and repressive properties. On the other hand, VDA-VDR complexes not only increased podocyte acetyl-histone 3 levels but also enhanced cytochrome P-450 family 24A1 expression, thus suggesting their acetylating and gene activation properties. AT1R-BLK- induced podocyte SMRT inhibited expression of the proapoptotic gene BAX through downregulation of Wip1 and phosphorylation of checkpoint kinase 2 in high-glucose milieu. Since SMRT-depleted podocytes lacked AT1R-BLK-mediated protection against DNA damage, it appears that SMRT is necessary for DNA repairs during AT1R-BLK. We conclude that AT1R-BLK provides podocyte protection in adverse milieus predominantly through SMRT expression and partly through unliganded VDR expression in 1,25(OH)2D-deficient states; on the other hand, AT1R-BLK contributes to liganded VDR expression in 1,25(OH)2D-sufficient states.
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Affiliation(s)
- Tejinder Singh
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Kamesh Ayasolla
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Partab Rai
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Nirupama Chandel
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Shabirul Haque
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Rivka Lederman
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | | | - Vasupradha Vethantham
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Amrita Chawla
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | | | - Moin A Saleem
- Academic Renal Unit, University of Bristol, Bristol, United Kingdom
| | - Guohua Ding
- Nephrology Division, Renmin Hospital of Wuhan, Wuhan, China, and
| | - Praveen N Chander
- Department of Pathology, New York Medical College, Valhalla, New York
| | - Ashwani Malhotra
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York
| | - Leonard G Meggs
- Nephrology Division, Ochsner Health System, New Orleans, Louisiana
| | - Pravin C Singhal
- Department of Medicine, Hofstra North Shore-LIJ Medical School and Feinstein Institute for Medical Research, Hempstead, New York;
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15
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Helsen C, Claessens F. Looking at nuclear receptors from a new angle. Mol Cell Endocrinol 2014; 382:97-106. [PMID: 24055275 DOI: 10.1016/j.mce.2013.09.009] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/05/2013] [Accepted: 09/06/2013] [Indexed: 01/01/2023]
Abstract
While the structures of the DNA- and ligand-binding domains of many nuclear receptors have been determined in great detail; the mechanisms by which these domains interact and possibly 'communicate' is still under debate. The first crystal structures of receptor dimers bound to ligand, DNA and coactivator peptides provided new insights in this matter. The observed binding modes revealed exciting new interaction surfaces between the different nuclear receptor domains. Such interfaces are proposed to be the route through which allosteric signals from the DNA are passed on to the ligand-binding domain and the activating functions of the receptor. The structural determinations of DNA-bound receptor dimers in solution, however, revealed an extended structure of the receptors. Here, we discuss these apparent contradictory structural data and their possible implications for the functioning of nuclear receptors.
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Affiliation(s)
- Christine Helsen
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, O&N1, Herestraat 49, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, O&N1, Herestraat 49, 3000 Leuven, Belgium.
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16
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Zhang Q, Kanterewicz B, Shoemaker S, Hu Q, Liu S, Atwood K, Hershberger P. Differential response to 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) in non-small cell lung cancer cells with distinct oncogene mutations. J Steroid Biochem Mol Biol 2013; 136:264-70. [PMID: 23026510 PMCID: PMC3674199 DOI: 10.1016/j.jsbmb.2012.09.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/17/2012] [Accepted: 09/20/2012] [Indexed: 01/08/2023]
Abstract
We previously demonstrated that non-small cell lung cancer (NSCLC) cells and primary human lung tumors aberrantly express the vitamin D3-catabolizing enzyme, CYP24, and that CYP24 restricts transcriptional regulation and growth control by 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) in NSCLC cells. To ascertain the basis for CYP24 dysregulation, we assembled a panel of cell lines that represent distinct molecular classes of lung cancer: cell lines were selected which harbored mutually exclusive mutations in either the K-ras or the Epidermal Growth Factor Receptor (EGFR) genes. We observed that K-ras mutant lines displayed a basal vitamin D receptor (VDR)(low)CYP24(high) phenotype, whereas EGFR mutant lines had a VDR(high)CYP24(low) phenotype. A mutation-associated difference in CYP24 expression was also observed in clinical specimens. Specifically, K-ras mutation was associated with a median 4.2-fold increase in CYP24 mRNA expression (p=4.8×10(-7)) compared to EGFR mutation in a series of 147 primary lung adenocarcinoma cases. Because of their differential basal expression of VDR and CYP24, we hypothesized that NSCLC cells with an EGFR mutation would be more responsive to 1,25(OH)2D3 treatment than those with a K-ras mutation. To test this, we measured the ability of 1,25(OH)2D3 to increase reporter gene activity, induce transcription of endogenous target genes, and suppress colony formation. In each assay, the extent of 1,25(OH)2D3 response was greater in EGFR mutation-positive HCC827 and H1975 cells than in K-ras mutation-positive A549 and 128.88T cells. We subsequently examined the effect of combining 1,25(OH)2D3 with erlotinib, which is used clinically in the treatment of EGFR mutation-positive NSCLC. 1,25(OH)2D3/erlotinib combination resulted in significantly greater growth inhibition than either single agent in both the erlotinib-sensitive HCC827 cell line and the erlotinib-resistant H1975 cell line. These data are the first to suggest that EGFR mutations may identify a lung cancer subset which remains responsive to and is likely to benefit from 1,25(OH)2D3 administration. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
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Affiliation(s)
- Qiuhong Zhang
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, United States
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17
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Yoshida S, Aihara KI, Ikeda Y, Sumitomo-Ueda Y, Uemoto R, Ishikawa K, Ise T, Yagi S, Iwase T, Mouri Y, Sakari M, Matsumoto T, Takeyama KI, Akaike M, Matsumoto M, Sata M, Walsh K, Kato S, Matsumoto T. Androgen receptor promotes sex-independent angiogenesis in response to ischemia and is required for activation of vascular endothelial growth factor receptor signaling. Circulation 2013; 128:60-71. [PMID: 23723256 DOI: 10.1161/circulationaha.113.001533] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Hypoandrogenemia is associated with an increased risk of ischemic diseases. Because actions of androgens are exerted through androgen receptor (AR) activation, we studied hind-limb ischemia in AR knockout mice to elucidate the role of AR in response to ischemia. METHODS AND RESULTS Both male and female AR knockout mice exhibited impaired blood flow recovery, more cellular apoptosis, and a higher incidence of autoamputation after ischemia. In ex vivo and in vivo angiogenesis studies, AR-deficient vascular endothelial cells showed reduced angiogenic capability. In ischemic limbs of AR knockout mice, reductions in the phosphorylation of the Akt protein kinase and endothelial nitric oxide synthase were observed despite a robust increase in hypoxia-inducible factor 1α and vascular endothelial cell growth factor (VEGF) gene expression. In in vitro studies, siRNA-mediated ablation of AR in vascular endothelial cells blunted VEGF-stimulated phosphorylation of Akt and endothelial nitric oxide synthase. Immunoprecipitation experiments documented an association between AR and kinase insert domain protein receptor that promoted the recruitment of downstream signaling components. CONCLUSIONS These results document a physiological role of AR in sex-independent angiogenic potency and provide evidence of novel cross-talk between the androgen/AR signaling and VEGF/kinase insert domain protein receptor signaling pathways.
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Affiliation(s)
- Sumiko Yoshida
- Department of Medicine and Bioregulatory Sciences, University of Tokushima Graduate School of Health Biosciences, 3-18-15 Kuramoto-cho Tokushima 770-8503, Japan.
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18
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Vitamin D and breast cancer: emerging concepts. Cancer Lett 2012; 334:95-100. [PMID: 23142286 DOI: 10.1016/j.canlet.2012.10.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/19/2012] [Accepted: 10/26/2012] [Indexed: 11/20/2022]
Abstract
The benefit of vitamin D in cancer prevention and to certain extent therapy has been well recognized. The active form of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)2 D3) is a natural ligand for vitamin D receptor (VDR). Since 1,25(OH)2D3 exerts toxic effects at a concentration that is beneficial, nearly 1500 analogs of vitamin D have been synthesized and evaluated for their efficacy in a variety of carcinogenesis and human cancer models both in vitro and in vivo. Among these only a handful of them have been approved for evaluation in clinical trials for leukemia, breast, prostate and colon cancers. The mechanism of vitamin D action is mediated by the nuclear VDR and the signaling cascade for its action is extensively reported. In this review we focus on the newer concepts for vitamin D action. These include (1) differential effects of vitamin D in maintaining cell proliferation when the cells are under stress but suppressing cell growth when the cells are transformed; (2) functional significance of VDR polymorphism in potential vitamin D responsiveness; (3) regulation of constitutive splicing of vitamin D target gene, CYP24a, by the hormone and its significance; and (4) regulation of microRNA by vitamin D in breast cancer. It is anticipated that the new work in these selective areas would expand the understanding of vitamin D in breast cancer prevention and therapy.
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19
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Alimirah F, Peng X, Yuan L, Mehta RR, von Knethen A, Choubey D, Mehta RG. Crosstalk between the peroxisome proliferator-activated receptor γ (PPARγ) and the vitamin D receptor (VDR) in human breast cancer cells: PPARγ binds to VDR and inhibits 1α,25-dihydroxyvitamin D3 mediated transactivation. Exp Cell Res 2012; 318:2490-7. [PMID: 22884583 DOI: 10.1016/j.yexcr.2012.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/24/2012] [Accepted: 07/26/2012] [Indexed: 10/28/2022]
Abstract
Heterodimerization and cross-talk between nuclear hormone receptors often occurs. For example, estrogen receptor alpha (ERα) physically binds to peroxisome proliferator-activated receptor gamma (PPARγ) and inhibits its transcriptional activity. The interaction between PPARγ and the vitamin D receptor (VDR) however, is unknown. Here, we elucidate the molecular mechanisms linking PPARγ and VDR signaling, and for the first time we show that PPARγ physically associates with VDR in human breast cancer cells. We found that overexpression of PPARγ decreased 1α,25-dihydroxyvitamin D(3) (1,25D(3)) mediated transcriptional activity of the vitamin D target gene, CYP24A1, by 49% and the activity of VDRE-luc, a vitamin D responsive reporter, by 75% in T47D human breast cancer cells. Deletion mutation experiments illustrated that helices 1 and 4 of PPARγ's hinge and ligand binding domains, respectively, governed this suppressive function. Additionally, abrogation of PPARγ's AF2 domain attenuated its repressive action on 1,25D(3) transactivation, indicating that this domain is integral in inhibiting VDR signaling. PPARγ was also found to compete with VDR for their binding partner retinoid X receptor alpha (RXRα). Overexpression of RXRα blocked PPARγ's suppressive effect on 1,25D(3) action, enhancing VDR signaling. In conclusion, these observations uncover molecular mechanisms connecting the PPARγ and VDR pathways.
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Affiliation(s)
- Fatouma Alimirah
- Cancer Biology Division, IIT Research Institute, 10 West 35th Street, Chicago, IL 60616, USA
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Orlov I, Rochel N, Moras D, Klaholz BP. Structure of the full human RXR/VDR nuclear receptor heterodimer complex with its DR3 target DNA. EMBO J 2011; 31:291-300. [PMID: 22179700 DOI: 10.1038/emboj.2011.445] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 11/10/2011] [Indexed: 11/09/2022] Open
Abstract
Transcription regulation by steroid hormones and other metabolites is mediated by nuclear receptors (NRs) such as the vitamin D and retinoid X receptors (VDR and RXR). Here, we present the cryo electron microscopy (cryo-EM) structure of the heterodimeric complex of the liganded human RXR and VDR bound to a consensus DNA response element forming a direct repeat (DR3). The cryo-EM map of the 100-kDa complex allows positioning the individual crystal structures of ligand- and DNA-binding domains (LBDs and DBDs). The LBDs are arranged perpendicular to the DNA and are located asymmetrically at the DNA 5'-end of the response element. The structure reveals that the VDR N-terminal A/B domain is located close to the DNA. The hinges of both VDR and RXR are fully visible and hold the complex in an open conformation in which co-regulators can bind. The asymmetric topology of the complex provides the structural basis for RXR being an adaptive partner within NR heterodimers, while the specific helical structure of VDR's hinge connects the 3'-bound DBD with the 5'-bound LBD and thereby serves as a conserved linker of defined length sensitive to mutational deletion.
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Affiliation(s)
- Igor Orlov
- Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, Illkirch, France
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