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Bikle DD. Protective actions of vitamin D in UVB induced skin cancer. Photochem Photobiol Sci 2013; 11:1808-16. [PMID: 22990497 DOI: 10.1039/c2pp25251a] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Non-melanoma skin cancers (NMSC) are the most common type of cancer, occurring at a rate of over 1 million per year in the United States. Although their metastatic potential is generally low, they can and do metastasize, especially in the immune compromised host, and their surgical treatment is often quite disfiguring. Ultraviolet radiation (UVR) as occurs with sunlight exposure is generally regarded as causal for these malignancies, but UVR is also required for vitamin D synthesis in the skin. Based on our own data and that reported in the literature, we hypothesize that the vitamin D produced in the skin serves to suppress UVR epidermal tumor formation. In this review we will first discuss the evidence supporting the conclusion that the vitamin D receptor (VDR), with or without its ligand 1,25-dihydroxyvitamin D, limits the propensity for cancer formation following UVR. We will then explore three potential mechanisms for this protection: inhibition of proliferation and stimulation of differentiation, immune regulation, and stimulation of DNA damage repair (DDR).
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Affiliation(s)
- Daniel D Bikle
- Department of Medicine, San Francisco VA Medical Center and University of California, San Francisco, CA, USA.
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SPROUTY2 is a β-catenin and FOXO3a target gene indicative of poor prognosis in colon cancer. Oncogene 2013; 33:1975-85. [DOI: 10.1038/onc.2013.140] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 03/02/2013] [Accepted: 03/04/2013] [Indexed: 01/02/2023]
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Meier-Abt F, Milani E, Roloff T, Brinkhaus H, Duss S, Meyer DS, Klebba I, Balwierz PJ, van Nimwegen E, Bentires-Alj M. Parity induces differentiation and reduces Wnt/Notch signaling ratio and proliferation potential of basal stem/progenitor cells isolated from mouse mammary epithelium. Breast Cancer Res 2013; 15:R36. [PMID: 23621987 PMCID: PMC3672662 DOI: 10.1186/bcr3419] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 03/20/2013] [Indexed: 12/11/2022] Open
Abstract
Introduction Early pregnancy has a strong protective effect against breast cancer in humans and rodents, but the underlying mechanism is unknown. Because breast cancers are thought to arise from specific cell subpopulations of mammary epithelia, we studied the effect of parity on the transcriptome and the differentiation/proliferation potential of specific luminal and basal mammary cells in mice. Methods Mammary epithelial cell subpopulations (luminal Sca1-, luminal Sca1+, basal stem/progenitor, and basal myoepithelial cells) were isolated by flow cytometry from parous and age-matched virgin mice and examined by using a combination of unbiased genomics, bioinformatics, in vitro colony formation, and in vivo limiting dilution transplantation assays. Specific findings were further investigated with immunohistochemistry in entire glands of parous and age-matched virgin mice. Results Transcriptome analysis revealed an upregulation of differentiation genes and a marked decrease in the Wnt/Notch signaling ratio in basal stem/progenitor cells of parous mice. Separate bioinformatics analyses showed reduced activity for the canonical Wnt transcription factor LEF1/TCF7 and increased activity for the Wnt repressor TCF3. This finding was specific for basal stem/progenitor cells and was associated with downregulation of potentially carcinogenic pathways and a reduction in the proliferation potential of this cell subpopulation in vitro and in vivo. As a possible mechanism for decreased Wnt signaling in basal stem/progenitor cells, we found a more than threefold reduction in the expression of the secreted Wnt ligand Wnt4 in total mammary cells from parous mice, which corresponded to a similar decrease in the proportion of Wnt4-secreting and estrogen/progesterone receptor-positive cells. Because recombinant Wnt4 rescued the proliferation defect of basal stem/progenitor cells in vitro, reduced Wnt4 secretion appears to be causally related to parity-induced alterations of basal stem/progenitor cell properties in mice. Conclusions By revealing that parity induces differentiation and downregulates the Wnt/Notch signaling ratio and the in vitro and in vivo proliferation potential of basal stem/progenitor cells in mice, our study sheds light on the long-term consequences of an early pregnancy. Furthermore, it opens the door to future studies assessing whether inhibitors of the Wnt pathway may be used to mimic the parity-induced protective effect against breast cancer.
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Kim HM, Lim YY, Kim MY, Son IP, Kim DH, Park SR, Seo SK, Lee MS, Mun SK, Kim CW, Kim BJ. Inhibitory effect of tianeptine on catagen induction in alopecia areata-like lesions induced by ultrasonic wave stress in mice. Clin Exp Dermatol 2013; 38:758-67. [PMID: 23581888 DOI: 10.1111/ced.12047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Alopecia areata (AA) is characterized by rapid and complete hair loss in one or multiple areas of the scalp. Stress is an important triggering factor in AA. AIM To identify the inhibitory effect of tianeptine on catagen induction in C57BL/6 mice with AA-like lesions induced by ultrasonic wave stress (UWS). METHODS The mice were divided into four groups. Group 1 received oral tianeptine before and after UWS; group 2 received oral tianeptine only after UWS; group 3 was given UWS treatment only; and group 4 (negative control group) was not given any treatment. Phototrichigraphy and dermatoscopy were used for assessment. Histological analysis was performed using haematoxylin and eosin, toluidine blue, Masson trichrome and Verhoeff-van Gieson stains. Immunohistochemical analysis was also performed. The level of apoptosis and expression of neuropeptides in the skin were assessed by terminal deoxynucleotidyl transferase dUTP nick end labelling and immunofluorescence assays. RESULTS Mice in group 1 had an increased rate of hair growth and greater hair-shaft thickness compared with mice in groups 2 and 3. In addition, mice in group 1 had a higher number of anagen hair follicles, increased synthesis of collagen and elastic fibres, decreased mast-cell degranulation, reduction in cell apoptosis in hair follicles, and recovery of vitamin D receptor expression. Expression of neuropeptides (substance P, calcitonin gene-related peptide) was not altered. CONCLUSIONS Tianeptine might play a role in suppressing catagen induction in a stress-induced AA mouse model.
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Affiliation(s)
- H M Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
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55
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Hyter S, Indra AK. Nuclear hormone receptor functions in keratinocyte and melanocyte homeostasis, epidermal carcinogenesis and melanomagenesis. FEBS Lett 2013; 587:529-41. [PMID: 23395795 PMCID: PMC3670764 DOI: 10.1016/j.febslet.2013.01.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 12/12/2012] [Accepted: 01/18/2013] [Indexed: 12/19/2022]
Abstract
Skin homeostasis is maintained, in part, through regulation of gene expression orchestrated by type II nuclear hormone receptors in a cell and context specific manner. This group of transcriptional regulators is implicated in various cellular processes including epidermal proliferation, differentiation, permeability barrier formation, follicular cycling and inflammatory responses. Endogenous ligands for the receptors regulate actions during skin development and maintenance of tissue homeostasis. Type II nuclear receptor signaling is also important for cellular crosstalk between multiple cell types in the skin. Overall, these nuclear receptors are critical players in keratinocyte and melanocyte biology and present targets for cutaneous disease management.
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Affiliation(s)
- Stephen Hyter
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, USA
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, USA
| | - Arup K Indra
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, USA
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, USA
- Environmental Health Science Center, Oregon State University, Corvallis, Oregon, USA
- Department of Dermatology, Oregon Health and Science University, Portland, Oregon, USA
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56
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Lim X, Nusse R. Wnt signaling in skin development, homeostasis, and disease. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a008029. [PMID: 23209129 DOI: 10.1101/cshperspect.a008029] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The skin and its appendages constitute the largest organ of the body. Its stratified epithelia offer protection from environmental stresses such as dehydration, irradiation, mechanical trauma, and pathogenic infection, whereas its appendages, like hair and sebaceous glands, help regulate body temperature as well as influence animal interaction and social behavior through camouflage and sexual signaling. To respond to and function effectively in a dynamic external environment, the skin and its appendages possess a remarkable ability to regenerate in a carefully controlled fashion. When this finely tuned homeostatic process is disrupted, skin diseases such as cancers may result. At present, the molecular signals that orchestrate cell proliferation, differentiation, and patterning in the skin remain incompletely understood. It is increasingly apparent that many morphogenetic pathways with key roles in development are also important in regulating skin biology. Of these, Wnt signaling has emerged as the dominant pathway controlling the patterning of skin and influencing the decisions of embryonic and adult stem cells to adopt the various cell lineages of the skin and its appendages, as well as subsequently controlling the function of differentiated skin cells. Here we will review established concepts and present recent advances in our understanding of the diverse roles that Wnt signaling plays in skin development, homeostasis, and disease.
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Affiliation(s)
- Xinhong Lim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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57
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Schwarz M, Münzel PA, Braeuning A. Non-melanoma skin cancer in mouse and man. Arch Toxicol 2012; 87:783-98. [PMID: 23266722 DOI: 10.1007/s00204-012-0998-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 12/12/2012] [Indexed: 12/30/2022]
Abstract
As a frontier organ, skin is exposed to different environmental and/or occupational chemicals which cause cutaneous cancers in experimental animals. In mice, 7,12-dimethylbenz[a]anthrancene (DMBA) and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) are frequently used as skin model tumor initiator and promoter, respectively. The sequential administration of DMBA and TPA leads to the appearance of a large number of benign papillomas, of which some convert later into invasive squamous cell carcinomas (SCC). At the molecular level, initiation of carcinogenesis in mouse skin consists in the mutational activation of the Ha-ras oncoprotein. HA-RAS mutations are rare in human SCC, but HA-RAS-mutated tumors appear in melanoma patients treated with B-raf inhibitors, indicating that initiated, HA-RAS-mutated stem cells also reside in human skin. Similarly, UV-induced human SCC show footprint mutations in the tumor suppressor gene TP53 which are also observed in UV-induced mouse SCC. Strong species differences exist with respect to phorbol ester-mediated tumor promotion. While certain mouse strains are very susceptible, other rodent species are much less sensitive. Likewise, humans appear to be much more resistant to phorbol ester-mediated skin toxicity. Papilloma formation as a result of a chemical insult is uncommon in men, questioning the relevance of this preneoplastic lesion for humans. However, skin tumorigenesis in the experimental situation and in humans appears to follow common molecular mechanisms, even though there are species differences in the morphological correlates to the preneoplastic state. Therefore, we recommend not simply labeling them as irrelevant for human risk assessment.
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Affiliation(s)
- Michael Schwarz
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, Wilhelmstr. 56, 72074, Tübingen, Germany.
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58
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Cadigan KM, Waterman ML. TCF/LEFs and Wnt signaling in the nucleus. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a007906. [PMID: 23024173 DOI: 10.1101/cshperspect.a007906] [Citation(s) in RCA: 517] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factors are the major end point mediators of Wnt/Wingless signaling throughout metazoans. TCF/LEFs are multifunctional proteins that use their sequence-specific DNA-binding and context-dependent interactions to specify which genes will be regulated by Wnts. Much of the work to define their actions has focused on their ability to repress target gene expression when Wnt signals are absent and to recruit β-catenin to target genes for activation when Wnts are present. Recent advances have highlighted how these on/off actions are regulated by Wnt signals and stabilized β-catenin. In contrast to invertebrates, which typically contain one TCF/LEF protein that can both activate and repress Wnt targets, gene duplication and isoform complexity of the family in vertebrates have led to specialization, in which individual TCF/LEF isoforms have distinct activities.
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Affiliation(s)
- Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, 48109-1048, USA
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Link W. Nuclear accumulation of β-catenin and forkhead box O3a in colon cancer: Dangerous liaison. World J Biol Chem 2012; 3:175-9. [PMID: 23024836 PMCID: PMC3460219 DOI: 10.4331/wjbc.v3.i9.175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 08/22/2012] [Accepted: 08/29/2012] [Indexed: 02/05/2023] Open
Abstract
The WNT/β-catenin and phosphoinositide 3-kinase (PI3K/AKT) signaling cascades both have been implicated in the formation and progression of colorectal cancer. Oncogenic PI3K/AKT signaling suppresses the activity of forkhead box O3a (FOXO3a) transcription factor through phosphorylation leading to its nuclear exclusion. Inhibition of the PI3K/AKT signaling by PI3K or AKT inhibitors results in the translocation of FOXO3a to the nucleus, and is considered to be a promising therapeutic strategy for many cancers including colon cancer. Now, however, a new study in Nature Medicine has revealed a nuclear interaction of β-catenin with FOXO3a as a promoter of metastatic progression in colon cancer. The work has important implications for the treatment of colon cancers, suggests a companion biomarker strategy to enable a personalized medicine approach, and offers an alternative therapeutic strategy to overcome resistance to PI3K and AKT inhibitors.
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Affiliation(s)
- Wolfgang Link
- Wolfgang Link, Regenerative Medicine Program, Department of Biomedical Sciences and Medicine, University of Algarve, 8005-139 Faro, Portugal
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60
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Patched knockout mouse models of Basal cell carcinoma. J Skin Cancer 2012; 2012:907543. [PMID: 23024864 PMCID: PMC3449132 DOI: 10.1155/2012/907543] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 08/06/2012] [Indexed: 01/22/2023] Open
Abstract
Basal cell carcinoma (BCC) is the most common human tumor. Mutations in the hedgehog (HH) receptor Patched (PTCH) are the main cause of BCC. Due to their high and increasing incidence, BCC are becoming all the more important for the health care system. Adequate animal models are required for the improvement of current treatment strategies. A good model should reflect the situation in humans (i.e., BCC initiation due to Ptch mutations on an immunocompetent background) and should allow for (i) BCC induction at a defined time point, (ii) analysis of defined BCC stages, and (iii) induction of BCC in 100% of animals. In addition, it should be easy to handle. Here, we compare several currently existing conventional and conditional Ptch knockout mouse models for BCC and their potential use in preclinical research. In addition, we provide new data using conditional Ptchflox/flox mice and the K5-Cre-ERT+/− driver.
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61
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β-catenin confers resistance to PI3K and AKT inhibitors and subverts FOXO3a to promote metastasis in colon cancer. Nat Med 2012; 18:892-901. [PMID: 22610277 DOI: 10.1038/nm.2772] [Citation(s) in RCA: 301] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 04/10/2012] [Indexed: 02/07/2023]
Abstract
The Wnt–β-catenin and PI3K-AKT-FOXO3a pathways have a central role in cancer. AKT phosporylates FOXO3a, relocating it from the cell nucleus to the cytoplasm, an effect that is reversed by PI3K and AKT inhibitors. Simultaneous hyperactivation of the Wnt–β-catenin pathway and inhibition of PI3K-AKT signaling promote nuclear accumulation of β-catenin and FOXO3a, respectively, promoting cell scattering and metastasis by regulating a defined set of target genes. Indeed, the anti-tumoral AKT inhibitor API-2 promotes nuclear FOXO3a accumulation and metastasis of cells with high nuclear β-catenin content. Nuclear β-catenin confers resistance to the FOXO3a-mediated apoptosis induced by PI3K and AKT inhibitors in patient-derived primary cultures and in corresponding xenograft tumors in mice. This resistance is reversed by XAV-939, an inhibitor of Wnt–β-catenin signaling. In the presence of high nuclear β-catenin content, activation of FOXO3a by PI3K or AKT inhibitors makes it behave as a metastasis inductor rather than a proapoptotic tumor suppressor. We show that it is possible to evaluate the β-catenin status of patients' carcinomas and the response of patient-derived cells to target-directed drugs that accumulate FOXO3a in the nucleus before deciding on a course of treatment. We propose that this evaluation could be essential to the provision of a safer and more effective personalized treatment.
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Martínez-Moreno JM, Muñoz-Castañeda JR, Herencia C, Oca AMD, Estepa JC, Canalejo R, Rodríguez-Ortiz ME, Perez-Martinez P, Aguilera-Tejero E, Canalejo A, Rodríguez M, Almadén Y. In vascular smooth muscle cells paricalcitol prevents phosphate-induced Wnt/β-catenin activation. Am J Physiol Renal Physiol 2012; 303:F1136-44. [PMID: 22874762 DOI: 10.1152/ajprenal.00684.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigates the differential effect of two vitamin D receptor agonists, calcitriol and paricalcitol, on human aortic smooth muscle cells calcification in vitro. Human vascular smooth muscle cells were incubated in a high phosphate (HP) medium alone or supplemented with either calcitriol 10(-8)M (HP + CTR) or paricalcitol 3·10(-8) M (HP + PC). HP medium induced calcification, which was associated with the upregulation of mRNA expression of osteogenic factors such as bone morphogenetic protein 2 (BMP2), Runx2/Cbfa1, Msx2, and osteocalcin. In these cells, activation of Wnt/β-catenin signaling was evidenced by the translocation of β-catenin into the nucleus and the increase in the expression of direct target genes as cyclin D1, axin 2, and VCAN/versican. Addition of calcitriol to HP medium (HP + CTR) further increased calcification and also enhanced the expression of osteogenic factors together with a significant elevation of nuclear β-catenin levels and the expression of cyclin D1, axin 2, and VCAN. By contrast, the addition of paricalcitol (HP + PC) not only reduced calcification but also downregulated the expression of BMP2 and other osteoblastic phenotype markers as well as the levels of nuclear β-catenin and the expression of its target genes. The role of Wnt/β-catenin on phosphate- and calcitriol-induced calcification was further demonstrated by the inhibition of calcification after addition of Dickkopf-related protein 1 (DKK-1), a specific natural antagonist of the Wnt/β-catenin signaling pathway. In conclusion, the differential effect of calcitriol and paricalcitol on vascular calcification appears to be mediated by a distinct regulation of the BMP and Wnt/β-catenin signaling pathways.
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Affiliation(s)
- Julio M Martínez-Moreno
- Unidad de Investigacion, IMIBIC, Hospital Reina Sofía, Avda. Menéndez Pidal s/n, Córdoba, Spain
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63
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Demay MB. The hair cycle and Vitamin D receptor. Arch Biochem Biophys 2012; 523:19-21. [DOI: 10.1016/j.abb.2011.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 09/30/2011] [Accepted: 10/03/2011] [Indexed: 10/16/2022]
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Rosen CJ, Adams JS, Bikle DD, Black DM, Demay MB, Manson JE, Murad MH, Kovacs CS. The nonskeletal effects of vitamin D: an Endocrine Society scientific statement. Endocr Rev 2012; 33:456-92. [PMID: 22596255 PMCID: PMC3365859 DOI: 10.1210/er.2012-1000] [Citation(s) in RCA: 483] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/18/2012] [Indexed: 12/18/2022]
Abstract
Significant controversy has emerged over the last decade concerning the effects of vitamin D on skeletal and nonskeletal tissues. The demonstration that the vitamin D receptor is expressed in virtually all cells of the body and the growing body of observational data supporting a relationship of serum 25-hydroxyvitamin D to chronic metabolic, cardiovascular, and neoplastic diseases have led to widespread utilization of vitamin D supplementation for the prevention and treatment of numerous disorders. In this paper, we review both the basic and clinical aspects of vitamin D in relation to nonskeletal organ systems. We begin by focusing on the molecular aspects of vitamin D, primarily by examining the structure and function of the vitamin D receptor. This is followed by a systematic review according to tissue type of the inherent biological plausibility, the strength of the observational data, and the levels of evidence that support or refute an association between vitamin D levels or supplementation and maternal/child health as well as various disease states. Although observational studies support a strong case for an association between vitamin D and musculoskeletal, cardiovascular, neoplastic, and metabolic disorders, there remains a paucity of large-scale and long-term randomized clinical trials. Thus, at this time, more studies are needed to definitively conclude that vitamin D can offer preventive and therapeutic benefits across a wide range of physiological states and chronic nonskeletal disorders.
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65
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Pereira F, Barbáchano A, Singh PK, Campbell MJ, Muñoz A, Larriba MJ. Vitamin D has wide regulatory effects on histone demethylase genes. Cell Cycle 2012; 11:1081-9. [PMID: 22370479 DOI: 10.4161/cc.11.6.19508] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vitamin D from the diet or synthesized in the skin upon UV-B irradiation is converted in the organism into the active metabolite 1α,25- dihydroxyvitamin D 3 [1,25(OH) 2D 3, calcitriol], a pleiotropic hormone with wide regulatory actions. The classical model of 1,25(OH)2D3 action implies the activation of the vitamin D receptor, which binds specific DNA sequences in its target genes and modulates their transcription rate. We have recently shown that 1,25(OH) 2D 3 induces the expression of the JMJD3 gene coding for a histone demethylase that is involved in epigenetic regulation. JMJD3 mediates the effects of 1,25(OH) 2D 3 on a subset of target genes and affects the expression of ZEB1, ZEB2 and SNAI1, inducers of epithelial-mesenchymal transition. Novel data indicate that 1,25(OH) 2D 3 has an unanticipated wide regulatory action on the expression of genes coding for histone demethylases of the Jumonji C (JmjC) domain and lysine-specific demethylase (LSD) families. Moreover, JMJD3 knockdown decreases the expression of miR‑200b and miR‑200c, two microRNAs targeting ZEB1 RNA. This may explain the upregulation of this transcription factor found in JMJD3-depleted cells. Thus, 1,25(OH) 2D 3 exerts an ample regulatory effect on the expression of histone-modifying enzymes involved in epigenetic regulation that may mediate its actions on gene transcription and cell phenotype.
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Affiliation(s)
- Fábio Pereira
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
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Abstract
The keratinocytes of the skin are unique in being not only the primary source of vitamin D for the body, but in possessing both the enzymatic machinery to metabolize the vitamin D produced to active metabolites (in particular 1,25(OH)(2)D) and the vitamin D receptor (VDR) that enables the keratinocytes to respond to the 1,25(OH)(2)D thus generated. Numerous functions of the skin are regulated by vitamin D and/or its receptor. These include inhibition of proliferation, stimulation of differentiation including formation of the permeability barrier, promotion of innate immunity, regulation of the hair follicle cycle, and suppression of tumor formation. Regulation of these actions is exerted by a number of different coregulator complexes including the coactivators vitamin D receptor interacting protein (DRIP) complex also known as Mediator and the steroid receptor coactivator (SRC) family (of which SRC 2 and 3 are found in keratincytes), the inhibitor hairless (Hr), and β-catenin whose impact on VDR function is complex. Different coregulators appear to be involved in different VDR regulated functions. This review will examine the various functions of vitamin D and its receptor in the skin, and explore the mechanisms by which these functions are regulated.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center/University of California, San Francisco, San Francisco, CA 94121, USA.
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Byers SW, Rowlands T, Beildeck M, Bong YS. Mechanism of action of vitamin D and the vitamin D receptor in colorectal cancer prevention and treatment. Rev Endocr Metab Disord 2012; 13:31-8. [PMID: 21861107 PMCID: PMC3262916 DOI: 10.1007/s11154-011-9196-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vitamin D and its analogs are potent inhibitors of colorectal cancer growth and metastasis. A number of recent studies have defined the intersections between the β-catenin-TCF pathway (a known contributor to colorectal cancer progression) and the vitamin D receptor (VDR) pathway, shedding light on the underlying mechanisms. Vitamin D also regulates the innate immune response, and as such influences susceptibility to inflammatory bowel disease, a predisposing factor in colorectal cancer. Understanding the role of vitamin D in these different contexts will enable development of next generation vitamin D analogs that will serve as both chemopreventatives and cancer therapeutics, without the accompanying side effects of hypercalcemia usually associated with high vitamin D intake. This review summarizes the mechanisms of action of vitamin D and the VDR in the context of the gastrointestinal tract and colorectal carcinogenesis.
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Affiliation(s)
- Stephen W Byers
- Georgetown-Lombardi Comprehensive Cancer Center, Georgetown University, E415 Research Building, 3970 Reservoir Road, NW, Washington, DC 20057, USA.
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Abstract
MicroRNAs (miRs) comprise a class of tiny (∼19-24 nucleotide), noncoding RNAs that regulate gene expression posttranscriptionally. Since the discovery of the founding members lin-4 and let-7 as key regulators in the developing nematode, miRs have been found throughout the eukaryotic kingdom. Functions for miRs are wide-ranging and encompass embryogenesis, stem cell biology, tissue differentiation, and human diseases including cancers. In this chapter, we begin by acquainting our readers with miRs and introducing them to their biogenesis. Then, we focus on the roles of miRs in stem cells during tissue development and homeostasis. We use mammalian skin as our main paradigm, but we also consider miR functions in several different types of adult stem cells. We conclude by discussing future challenges that will lead to a comprehensive understanding of miR functions in stem cells and their lineages.
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Affiliation(s)
- Rui Yi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, Colorado, USA
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Oda Y, Hu L, Bul V, Elalieh H, Reddy JK, Bikle DD. Coactivator MED1 ablation in keratinocytes results in hair-cycling defects and epidermal alterations. J Invest Dermatol 2011; 132:1075-83. [PMID: 22189783 PMCID: PMC3400544 DOI: 10.1038/jid.2011.430] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The transcriptional coactivator complex Mediator facilitates transcription of nuclear hormone receptors and other transcription factors. We have previously isolated the Mediator complex from primary keratinocytes as the vitamin D receptor interacting protein complex. We identified a role for Mediator in keratinocyte proliferation and differentiation in cultured keratinocytes. Here, we investigated the in vivo role of Mediator by generating conditional null mice, where a critical subunit of the Mediator complex, MED1, is deleted from their keratinocytes. The MED1 ablation resulted in aberrant hair differentiation and cycling leading to hair loss. During the first hair follicle cycle, MED1 deletion resulted in a rapid regression of the hair follicles. Hair differentiation was reduced, and β-catenin/vitamin D receptor (VDR) regulated gene expression was dramatically decreased. In the subsequent adult hair cycle, MED1 ablation activated the initiation of hair follicle cycling. Shh signaling was increased, but terminal differentiation was not sufficient. Deletion of MED1 also caused hyper-proliferation of interfollicular epidermal keratinocytes, and increased the expression of epidermal differentiation markers. These results indicate that MED1 plays a critical role in regulating hair/epidermal proliferation and differentiation.
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Affiliation(s)
- Yuko Oda
- Department of Medicine and Endocrinology, University of California, San Francisco and Veterans Affairs Medical Center San Francisco, San Francisco, California 94121, USA.
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70
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Abstract
The keratinocytes of the skin are unique in being not only the primary source of vitamin D for the body, but in possessing the enzymatic machinery to metabolize vitamin D to its active metabolite 1,25(OH)(2)D. Furthermore, these cells also express the vitamin D receptor (VDR) that enables them to respond to the 1,25(OH)(2)D they produce. Numerous functions of the skin are regulated by 1,25(OH)(2)D and/or its receptor. These include inhibition of proliferation, stimulation of differentiation including formation of the permeability barrier, promotion of innate immunity, and promotion of the hair follicle cycle. Regulation of these actions is exerted by a number of different coregulators including the coactivators DRIP and SRC, the cosuppressor hairless (Hr), and β-catenin. This review will examine the regulation of vitamin D production and metabolism in the skin, and explore the various functions regulated by 1,25(OH)(2)D and its receptor.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center, University of California San Francisco, San Francisco, CA 94121, USA.
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71
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Santos A, Bakker AD, Willems HME, Bravenboer N, Bronckers ALJJ, Klein-Nulend J. Mechanical loading stimulates BMP7, but not BMP2, production by osteocytes. Calcif Tissue Int 2011; 89:318-26. [PMID: 21842277 DOI: 10.1007/s00223-011-9521-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 07/22/2011] [Indexed: 01/26/2023]
Abstract
Bone mechanical adaptation is a cellular process that allows bones to adapt their mass and structure to mechanical loading. This process is governed by the osteocytes, which in response to mechanical loading produce signaling molecules that affect osteoblasts and osteoclasts. Bone morphogenic proteins (BMPs) are excellent candidates as signaling molecules, but it is unknown whether mechanically stimulated osteocytes affect bone adaptation through BMP production. Therefore, the aim of this study was to assess whether osteocytes produce BMPs in response to mechanical loading. In addition, since BMP7 has a vitamin D receptor (VDR) response element in the promoter region, we also investigated whether VDR is involved in the BMP7 response to mechanical loading. Human or VDR(-/-) mouse primary bone cells were submitted in vitro to 1 h pulsating fluid flow (PFF) and postincubated without PFF (PI) for 1-24 h, and gene and protein expression of BMP2 and BMP7 were quantified. In human bone cells, PFF did not change BMP2 gene expression, but it upregulated BMP7 gene expression by 4.4- to 5.6-fold at 1-3 h PI and stimulated BMP7 protein expression by 2.4-fold at 6 h PI. PFF did not stimulate BMP7 gene expression in VDR(-/-) mouse bone cells. These results show for the first time that mechanical loading upregulates BMP7, likely via the VDR, but not BMP2, gene and protein expression in osteocytes in vitro. Since BMP7 plays a major role in bone development and remodeling, these data might contribute to a better understanding of the mechanism leading to the mechanical adaptation of bone.
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Affiliation(s)
- Ana Santos
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Research Institute MOVE, Gustav Mahlerlaan, LA, The Netherlands
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72
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Larriba MJ, Ordóñez-Morán P, Chicote I, Martín-Fernández G, Puig I, Muñoz A, Pálmer HG. Vitamin D receptor deficiency enhances Wnt/β-catenin signaling and tumor burden in colon cancer. PLoS One 2011; 6:e23524. [PMID: 21858154 PMCID: PMC3156234 DOI: 10.1371/journal.pone.0023524] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 07/19/2011] [Indexed: 02/06/2023] Open
Abstract
Aberrant activation of the Wnt/β-catenin pathway is critical for the initiation and progression of most colon cancers. This activation provokes the accumulation of nuclear β-catenin and the induction of its target genes. Apc(min/+) mice are the most commonly used model for colon cancer. They harbor a mutated Apc allele and develop intestinal adenomas and carcinomas during the first months of life. This phenotype is caused by the mutation of the second Apc allele and the consequent accumulation of nuclear β-catenin in the affected cells. Here we describe that vitamin D receptor (VDR) is a crucial modulator of nuclear β-catenin levels in colon cancer in vivo. By appropriate breeding of Apc(min/+) mice and Vdr(+/-) mice we have generated animals expressing a mutated Apc allele and two, one, or none Vdr wild type alleles. Lack of Vdr increased the number of colonic Aberrant Crypt Foci (ACF) but not that of adenomas or carcinomas in either small intestine or colon. Importantly, colon ACF and tumors of Apc(min/+)Vdr(-/-) mice had increased nuclear β-catenin and the tumors reached a larger size than those of Apc(min/+)Vdr(+/+). Both ACF and carcinomas in Apc(min/+)Vdr(-/-) mice showed higher expression of β-catenin/TCF target genes. In line with this, VDR knock-down in cultured human colon cancer cells enhanced β-catenin nuclear content and target gene expression. Consistently, VDR depletion abrogated the capacity of 1,25(OH)(2)D(3) to promote the relocation of β-catenin from the nucleus to the plasma membrane and to inhibit β-catenin/TCF target genes. In conclusion, VDR controls the level of nuclear β-catenin in colon cancer cells and can therefore attenuate the impact of oncogenic mutations that activate the Wnt/β-catenin pathway.
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Affiliation(s)
- María Jesús Larriba
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Paloma Ordóñez-Morán
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Irene Chicote
- Vall d'Hebrón Institute of Oncology, Stem Cells and Cancer Laboratory, Barcelona, Spain
| | - Génesis Martín-Fernández
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Isabel Puig
- Vall d'Hebrón Institute of Oncology, Stem Cells and Cancer Laboratory, Barcelona, Spain
| | - Alberto Muñoz
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Héctor G. Pálmer
- Vall d'Hebrón Institute of Oncology, Stem Cells and Cancer Laboratory, Barcelona, Spain
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Overexpression of hedgehog signaling is associated with epidermal tumor formation in vitamin D receptor-null mice. J Invest Dermatol 2011; 131:2289-97. [PMID: 21814234 PMCID: PMC3193543 DOI: 10.1038/jid.2011.196] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The vitamin D receptor (VDR) ligand, 1,25(OH)2D3, reduces proliferation and enhances differentiation and thus has been investigated for a role in preventing or treating cancer. Mice deficient for the VDR display a hyperproliferative response in the hair follicle and epidermis and decreased epidermal differentiation. Unlike their wild type littermates, when treated with 7,12 dimethylbenzanthracene (DMBA) or UVB, they develop skin tumors, including some characteristic of over-expression of the hedgehog (Hh) pathway. Both the epidermis and utricles of the VDR null animals over-express elements of the Hh pathway [Sonic Hedgehog (Shh, 2.02 fold), Patched1 1.58 fold, Smoothened 3.54 fold, Gli1 1.17 fold, and Gli2 1.66 fold]. This over-expression occurs at an age (11 weeks) where epidermal hyperproliferation is most visible and is spatially controlled in the epidermis. DMBA or UVB induced tumors in the VDR null mice also over-express elements of this pathway. Moreover, 1,25(OH)2D3 down-regulates the expression of some members of the Hh pathway in an epidermal explants culture system, suggesting a direct regulation by 1,25(OH)2D3. Our results suggest that increased expression of Shh in the keratinocytes of the VDR null animal activates the Hh pathway, predisposing the skin to the development of both malignant and benign epidermal neoplasms.
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74
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Tang JY, Xiao TZ, Oda Y, Chang KS, Shpall E, Wu A, So PL, Hebert J, Bikle D, Epstein EH. Vitamin D3 inhibits hedgehog signaling and proliferation in murine Basal cell carcinomas. Cancer Prev Res (Phila) 2011; 4:744-51. [PMID: 21436386 PMCID: PMC3088781 DOI: 10.1158/1940-6207.capr-10-0285] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Constitutive Hedgehog (HH) signaling underlies several human tumors, including basal cell carcinoma (BCC). Recently, Bijlsma and colleagues reported a new biologic function for vitamin D3 in suppressing HH signaling in an in vitro model system. On the basis of that work, we have assessed effects of vitamin D3 on HH signaling and proliferation of murine BCCs in vitro and in vivo. We find that indeed in BCC cells, vitamin D3 blocks both proliferation and HH signaling as assessed by mRNA expression of the HH target gene Gli1. These effects of vitamin D3 on Gli1 expression and on BCC cell proliferation are comparable to the effects of cyclopamine, a known inhibitor of the HH pathway. These results are specific for vitamin D3, because the precursor 7-dehydrocholesterol and the downstream products 25-hydroxy vitamin D3 [25(OH)D] and 1,25-dihydroxy vitamin D3 [1,25(OH)(2)D] are considerably less effective in reducing either Gli1 mRNA or cellular proliferation. Moreover, these effects seem to be independent of the vitamin D receptor (VDR) because short hairpin RNA knockdown of VDR does not abrogate the anti-HH effects of D3 despite reducing expression of the VDR target gene 24-hydroxylase. Finally, topical vitamin D3 treatment of existing murine BCC tumors significantly decreases Gli1 and Ki67 staining. Thus, topical vitamin D3 acting via its HH inhibiting effect may hold promise as an effective anti-BCC agent.
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MESH Headings
- Animals
- Blotting, Western
- Bone Density Conservation Agents/pharmacology
- Carcinoma, Basal Cell/genetics
- Carcinoma, Basal Cell/metabolism
- Carcinoma, Basal Cell/pathology
- Cell Differentiation/drug effects
- Cell Proliferation/drug effects
- Cells, Cultured
- Cerebellar Neoplasms/genetics
- Cerebellar Neoplasms/metabolism
- Cerebellar Neoplasms/pathology
- Cholecalciferol/pharmacology
- Hedgehog Proteins/genetics
- Hedgehog Proteins/metabolism
- Immunoenzyme Techniques
- Keratinocytes/cytology
- Keratinocytes/metabolism
- Kruppel-Like Transcription Factors/genetics
- Kruppel-Like Transcription Factors/metabolism
- Medulloblastoma/genetics
- Medulloblastoma/metabolism
- Medulloblastoma/pathology
- Mice
- RNA, Messenger/genetics
- RNA, Small Interfering/genetics
- Receptors, Calcitriol/antagonists & inhibitors
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Steroid Hydroxylases/genetics
- Steroid Hydroxylases/metabolism
- Vitamin D3 24-Hydroxylase
- Zinc Finger Protein GLI1
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Affiliation(s)
- Jean Y Tang
- Department of Dermatology, Stanford University School of Medicine, Redwood City, CA 94063-5334, USA.
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75
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Luderer HF, Gori F, Demay MB. Lymphoid enhancer-binding factor-1 (LEF1) interacts with the DNA-binding domain of the vitamin D receptor. J Biol Chem 2011; 286:18444-51. [PMID: 21471213 DOI: 10.1074/jbc.m110.188219] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ligand-independent actions of the vitamin D receptor (VDR) are required for normal post-morphogenic hair cycles; however, the molecular mechanisms by which the VDR exerts these actions are not clear. Previous studies demonstrated impaired regulation of the canonical Wnt signaling pathway in primary keratinocytes lacking the VDR. To identify the key effector of canonical Wnt signaling that interacts with the VDR, GST pulldown studies were performed. A novel interaction between the VDR and LEF1 (lymphoid enhancer-binding factor-1) that is independent of β-catenin was identified. This interaction is dependent upon sequences within the N-terminal region of the VDR, a domain required for VDR-DNA interactions and normal hair cycling in mice. Mutation of specific residues within the N-terminal region of the VDR not only abrogated interactions between the VDR and LEF1 but also impaired the ability of the VDR to enhance Wnt signaling in vdr(-/-) primary keratinocytes. Thus, this study demonstrates a novel interaction between the VDR and LEF1 that is mediated by the DNA-binding domain of the VDR and that is required for normal canonical Wnt signaling in keratinocytes.
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Affiliation(s)
- Hilary F Luderer
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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76
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Bikle DD. The vitamin D receptor: a tumor suppressor in skin. DISCOVERY MEDICINE 2011; 11:7-17. [PMID: 21276406 PMCID: PMC4113511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Epidemiologic evidence supporting a major chemopreventive role for vitamin D in various malignancies is strong. Likewise the use of the active metabolite of vitamin D, 1,25(OH)(2)D(3), and its analogs to prevent and/or treat a wide variety of malignancies in animals is well established. The evidence has been less compelling for epidermal carcinogenesis perhaps because the same agent that produces vitamin D in the skin, UVB radiation (UVR), is also the same agent that results in most epidermal malignancies. However, recent studies indicate that the role of vitamin D and its receptor (VDR) in protecting against the development of epidermal tumors deserves a closer look. One such study found mice lacking the VDR were quite sensitive to epidermal tumor formation following the administration of the carcinogen DMBA. A more recent study showed that these mice were similarly more sensitive to tumor formation following UVR, results we have confirmed. The epidermis of the VDR null mouse is hyperproliferative with gross distortion of hair follicles, structures that may provide the origin for the tumors found in the skin following such treatment. Two interacting pathways critical for epidermal and hair follicle function, beta-catenin and hedgehog (Hh), result in epidermal tumors when they are activated abnormally. Thus, we considered the possibility that loss of VDR predisposes to epidermal tumor formation by activation of either or both beta-catenin and Hh signaling. We determined that all elements of the Hh signaling pathway are upregulated in the epidermis and utricles of the VDR null mouse, and that 1,25(OH)(2)D(3) suppresses the expression of these elements in normal mouse skin. In addition we observed that the transcriptional activity of beta-catenin was increased in keratinocytes lacking the VDR. These results lead us to the hypothesis that the VDR with its ligand 1,25(OH)(2)D(3) functions as a tumor suppressor with respect to epidermal tumor formation in response to UVR by regulating Hh and beta-catenin signaling.
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Affiliation(s)
- Daniel David Bikle
- Department of Medicine, University of California San Francisco, San Francisco Veterans Affairs Medical Center, 94121, USA.
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77
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Yu C, Fedoric B, Anderson PH, Lopez AF, Grimbaldeston MA. Vitamin D3 signalling to mast cells: A new regulatory axis. Int J Biochem Cell Biol 2011; 43:41-6. [DOI: 10.1016/j.biocel.2010.10.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Revised: 10/16/2010] [Accepted: 10/18/2010] [Indexed: 11/26/2022]
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78
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Abstract
Pluripotency is defined as the capacity of individual cells to initiate all lineages of the mature organism in response to signals from the embryo or cell culture environment. A pluripotent cell has no predetermined programme; it is a blank slate. This is the foundation of mammalian development and of ES (embryonic stem) cell biology. What are the design principles of this naïve cell state? How is pluripotency acquired and maintained? Suppressing activation of ERKs (extracellular-signal-regulated kinases) is critical to establishing and sustaining ES cells. Inhibition of GSK3 (glycogen synthase kinase 3) reinforces this effect. We review the effect of selective kinase inhibitors on pluripotent cells and consider how these effects are mediated. We propose that ES cells represent a ground state, meaning a basal proliferative state that is free of epigenetic restriction and has minimal requirements for extrinsic stimuli. The stability of this state is reflected in the homogeneity of ES cell populations cultured in the presence of small-molecule inhibitors of MEK (mitogen-activated protein kinase/ERK kinase) and GSK3.
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Affiliation(s)
- Jason Wray
- Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
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79
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Tiede S, Bohm K, Meier N, Funk W, Paus R. Endocrine controls of primary adult human stem cell biology: thyroid hormones stimulate keratin 15 expression, apoptosis, and differentiation in human hair follicle epithelial stem cells in situ and in vitro. Eur J Cell Biol 2010; 89:769-77. [PMID: 20656376 DOI: 10.1016/j.ejcb.2010.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 06/17/2010] [Accepted: 06/21/2010] [Indexed: 01/08/2023] Open
Abstract
Here we demonstrate that physiological concentrations of the thyroid hormones T3 and T4 enhance the KERATIN 15 promoter activity and expression in epithelial stem cells of adult human scalp hair follicles in situ and in vitro. Additionally, T3 and T4 stimulate expression of the immuno-inhibitory surface molecule CD200. Subsequently, T3 and T4 induce apoptosis and differentiation and inhibit clonal growth of these progenitor cells in vitro. These data suggest that human hair follicle bulge-derived epithelial stem cells underlie profound, previously unknown hormonal regulation by thyroid hormones, and show that primary human keratin 15-GFP+ progenitor cells can be exploited to further elucidate fundamental endocrine controls of human epithelial stem cells.
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Affiliation(s)
- S Tiede
- Department of Dermatology, University of Lübeck, Lübeck, Germany.
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80
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Bikle DD, Teichert A, Arnold LA, Uchida Y, Elias PM, Oda Y. Differential regulation of epidermal function by VDR coactivators. J Steroid Biochem Mol Biol 2010; 121:308-13. [PMID: 20298785 PMCID: PMC2906691 DOI: 10.1016/j.jsbmb.2010.03.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 03/06/2010] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
Abstract
The transcriptional activity of the vitamin D receptor (VDR) is regulated by a number of coactivator and corepressor complexes, which bind to the VDR in a ligand (1,25(OH)2D3) dependent (coactivators) or inhibited (corepressors) process. In the keratinocyte the major coactivator complexes include the vitamin D interacting protein (DRIP) complex and the steroid receptor coactivator (SRC) complexes. These coactivator complexes are not interchangeable in their regulation of keratinocyte proliferation and differentiation. We found that the DRIP complex is the main complex binding to VDR in the proliferating keratinocyte, whereas SRC2 and 3 and their associated proteins are the major coactivators binding to VDR in the differentiated keratinocyte. Moreover, we have found a specific role for DRIP205 in the regulation of beta-catenin pathways regulating keratinocyte proliferation, whereas SRC3 uniquely regulates the ability of 1,25(OH)2D3 to induce more differentiated functions such as lipid synthesis and processing required for permeability barrier formation and the innate immune response triggered by disruption of the barrier. These findings provide a basis by which we can understand how one receptor (VDR) and one ligand (1,25(OH)2D3) can regulate a large number of genes in a sequential and differentiation specific fashion.
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Affiliation(s)
- D D Bikle
- Endocrine Research Unit, Department of Medicine, Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
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81
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The transcriptional coactivator DRIP/mediator complex is involved in vitamin D receptor function and regulates keratinocyte proliferation and differentiation. J Invest Dermatol 2010; 130:2377-88. [PMID: 20520624 DOI: 10.1038/jid.2010.148] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mediator is a multisubunit coactivator complex that facilitates transcription of nuclear receptors. We investigated the role of the mediator complex as a coactivator for vitamin D receptor (VDR) in keratinocytes. Using VDR affinity beads, the vitamin D receptor interacting protein (DRIP)/mediator complex was purified from primary keratinocytes, and its subunit composition was determined by mass spectrometry. The complex included core subunits, such as DRIP205/MED1 (MED1), that directly binds to VDR. Additional subunits were identified that are components of the RNA polymerase II complex. The functions of different mediator components were investigated by silencing its subunits. The core subunit MED1 facilitates VDR activity and regulating keratinocyte proliferation and differentiation. A newly described subunit MED21 also has a role in promoting keratinocyte proliferation and differentiation, whereas MED10 has an inhibitory role. Blocking MED1/MED21 expression caused hyperproliferation of keratinocytes, accompanied by increases in mRNA expression of the cell cycle regulator cyclin D1 and/or glioma-associated oncogene homolog. Blocking MED1 or MED21 expression also resulted in defects in calcium-induced keratinocyte differentiation, as indicated by decreased expression of differentiation markers and decreased translocation of E-cadherin to the membrane. These results show that keratinocytes use the transcriptional coactivator mediator to regulate VDR functions and control keratinocyte proliferation and differentiation.
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82
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Méchin MC, Coudane F, Adoue V, Arnaud J, Duplan H, Charveron M, Schmitt AM, Takahara H, Serre G, Simon M. Deimination is regulated at multiple levels including auto-deimination of peptidylarginine deiminases. Cell Mol Life Sci 2010; 67:1491-503. [PMID: 20111885 PMCID: PMC11115946 DOI: 10.1007/s00018-010-0262-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/01/2009] [Accepted: 01/07/2010] [Indexed: 10/19/2022]
Abstract
Peptidylarginine deiminases (PADs) catalyze deimination, converting arginyl to citrullyl residues. Only three PAD isotypes are detected in the epidermis where they play a crucial role, targeting filaggrin, a key actor for the tissue hydration and barrier functions. Their expression and activation depends on the keratinocyte differentiation state. To investigate this regulation, we used primary keratinocytes induced to differentiate either by increasing cell-density or by treatment with vitamin D. High cell-density increased PAD1 and 3, but not PAD2, at the mRNA and protein levels, and up-regulated protein deimination. By contrast, vitamin D increased PAD1-3 mRNA amounts, with distinct kinetics, but neither the proteins nor the deimination rate. Furthermore, auto-deimination was shown to decrease PAD activity, increasing the distances between the four major amino acids of the active site. In summary, deimination can be regulated at multiple levels: transcription of the PADI genes, translation of the corresponding mRNAs, and auto-deimination of PADs.
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Affiliation(s)
- Marie-Claire Méchin
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
| | - Fanny Coudane
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
| | - Véronique Adoue
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
| | - Jacques Arnaud
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
| | - Hélène Duplan
- Centre Européen de Recherche sur la Peau et les Epithéliums de Revêtement (CERPER), Pierre Fabre Dermo-Cosmétique, Toulouse, France
| | - Marie Charveron
- Centre Européen de Recherche sur la Peau et les Epithéliums de Revêtement (CERPER), Pierre Fabre Dermo-Cosmétique, Toulouse, France
| | - Anne-Marie Schmitt
- Centre Européen de Recherche sur la Peau et les Epithéliums de Revêtement (CERPER), Pierre Fabre Dermo-Cosmétique, Toulouse, France
| | - Hidenari Takahara
- Department of Applied Biological Resource Sciences, School of Agriculture, University of Ibaraki, Ibaraki, Japan
| | - Guy Serre
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
| | - Michel Simon
- CNRS-University of Toulouse III, UMR5165, Institut Fédératif de Recherche 150 (INSERM-CNRS-Université paul Sabatier-Centre Hospitalier Universitaire de Toulouse), CHU Purpan, Place du Dr Baylac TSA40031, 31059 Toulouse Cedex 9, France
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83
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Baker CM, Verstuyf A, Jensen KB, Watt FM. Differential sensitivity of epidermal cell subpopulations to beta-catenin-induced ectopic hair follicle formation. Dev Biol 2010; 343:40-50. [PMID: 20398648 PMCID: PMC3098388 DOI: 10.1016/j.ydbio.2010.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/24/2010] [Accepted: 04/08/2010] [Indexed: 12/02/2022]
Abstract
Wnt signalling is required for hair follicle development and for the growth phase (anagen) of postnatal follicles. When the pathway is activated at high levels in adult mouse epidermis, ectopic follicles form from existing follicles, interfollicular epidermis (IFE) and sebaceous glands, revealing a remarkable ability of the tissue to be reprogrammed. To compare the competence of different epidermal cell populations to form ectopic follicles, we expressed a 4-hydroxy-tamoxifen (4OHT) inducible, stabilised β-catenin transgene (ΔNβ-cateninER) under the control of two different promoters. We targeted the reservoir of stem cells in the hair follicle bulge via the keratin 15 (K15) promoter and targeted the sebaceous glands and base of the follicle (bulb) with a truncated K5 promoter (ΔK5). No ectopic follicles formed in the IFE in either model, establishing the autonomy of the IFE stem cell compartment in undamaged epidermis. Activation of β-catenin in the bulge stimulated proliferation and bulge expansion. Existing hair follicles entered anagen, but no ectopic follicles formed. ΔK5ΔNβ-cateninER expressing hair follicles also entered anagen on 4OHT treatment. In addition, a subpopulation of cells at the base of the sebaceous gland readily formed ectopic follicles, resulting in complete and reversible conversion of sebaceous glands into hair follicles. Combined activation of β-catenin and the vitamin D receptor enhanced differentiation of sebaceous gland-derived hair follicles and stimulated ectopic follicle formation in the hair follicle bulb, but not in the bulge. Our results suggest that the bulge and sebaceous gland are, respectively, non-permissive and permissive niches for Wnt induced hair follicle differentiation.
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Affiliation(s)
- Christopher M. Baker
- CRUK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Annemieke Verstuyf
- Laboratory of Experimental Medicine and Endocrinology, KULeuven, Herestraat 49 bus 902, 3000 Leuven, Belgium
| | - Kim B. Jensen
- Wellcome Trust Centre for Stem Cell Research, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Fiona M. Watt
- CRUK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
- Wellcome Trust Centre for Stem Cell Research, Tennis Court Road, Cambridge CB2 1QR, UK
- Corresponding author. CRUK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK. Fax: +44 1223 404573.
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84
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Nitzki F, Zibat A, König S, Wijgerde M, Rosenberger A, Brembeck FH, Carstens PO, Frommhold A, Uhmann A, Klingler S, Reifenberger J, Pukrop T, Aberger F, Schulz-Schaeffer W, Hahn H. Tumor stroma-derived Wnt5a induces differentiation of basal cell carcinoma of Ptch-mutant mice via CaMKII. Cancer Res 2010; 70:2739-48. [PMID: 20233865 DOI: 10.1158/0008-5472.can-09-3743] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Basal cell carcinoma (BCC) is the most common skin tumor in humans. Although BCCs rarely metastasize, they can cause significant morbidity due to local aggressiveness. Approximately 20% of BCCs show signs of spontaneous regression. The understanding of molecular events mediating spontaneous regression has the potential to reduce morbidity of BCC and, potentially, other tumors, if translated into tumor therapies. We show that BCCs induced in conditional Ptch(flox/flox)ERT2(+/-) knockout mice regress with time and show a more differentiated phenotype. Differentiation is accompanied by Wnt5a expression in the tumor stroma, which is first detectable at the fully developed tumor stage. Coculture experiments revealed that Wnt5a is upregulated in tumor-adjacent macrophages by soluble signals derived from BCC cells. In turn, Wnt5a induces the expression of the differentiation marker K10 in tumor cells, which is mediated by Wnt/Ca(2+) signaling in a CaMKII-dependent manner. These data support a role of stromal Wnt5a in BCC differentiation and regression, which may have important implications for development of new treatment strategies for this tumor. Taken together, our results establish BCC as an easily accessible model of tumor regression. The regression of BCC despite sustained Hedgehog signaling activity seems to be mediated by tumor-stromal interactions via Wnt5a signaling.
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Affiliation(s)
- Frauke Nitzki
- Institute of Human Genetics, University of Goettingen, Goettingen, Germany
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85
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Abstract
The keratinocytes of the skin are unique in being not only the primary source of vitamin D for the body, but also possessing the enzymatic machinery to metabolize vitamin D to active metabolites [in particular, 1,25 dihydroxyvitamin D (1,25(OH)(2)D)] and the vitamin D receptor (VDR) that enables the keratinocytes to respond to the 1,25(OH)(2)D they produce. Numerous functions of the skin are regulated by vitamin D and/or its receptor: these include inhibition of proliferation, stimulation of differentiation including formation of the permeability barrier, promotion of innate immunity, regulation of the hair follicle cycle, and suppression of tumor formation. Regulation of these actions is exerted by a number of different coregulators including the coactivators DRIP and SRC, a less well known inhibitor, hairless, and beta-catenin. Different coregulators appear to be involved in different VDR-regulated functions. This review examines the various functions of vitamin D and its receptor, and to the extent known explores the mechanisms by which these functions are regulated.
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Affiliation(s)
- Daniel D Bikle
- Veterans Affairs Medical Center, University of California, 4150 Clement St (111N), San Francisco, CA 94121, USA.
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86
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Egan JB, Thompson PA, Ashbeck EL, Conti DV, Duggan D, Hibler E, Jurutka PW, Leroy EC, Martínez ME, Mount D, Jacobs ET. Genetic polymorphisms in vitamin D receptor VDR/RXRA influence the likelihood of colon adenoma recurrence. Cancer Res 2010; 70:1496-504. [PMID: 20145122 DOI: 10.1158/0008-5472.can-09-3264] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Low circulating levels of vitamin D affect colorectal cancer risk. The biological actions of the hormonal form of vitamin D, 1,25(OH)(2)D(3), are mediated by the vitamin D receptor (VDR), which heterodimerizes with retinoid X receptors (RXR). Using a single nucleotide polymorphism (SNP) tagging approach, we assessed the association between genetic variations in RXRA and VDR and odds of recurrent (metachronous) colorectal neoplasia in a pooled population of two studies. A total of 32 tag SNPs in RXRA and 42 in VDR were analyzed in 1,439 participants. A gene-level association was observed for RXRA and any (P = 0.04) or proximal (P = 0.03) metachronous neoplasia. No gene-level associations were observed for VDR, nor was any single SNP in VDR related to any metachronous adenoma after correction for multiple comparisons. In contrast, the association between RXRA SNP rs7861779 and proximal metachronous neoplasia was of borderline statistical significance [odds ratio (OR), 0.68; 95% confidence interval (95% CI), 0.53-0.86; unadjusted P = 0.001; adjusted P = 0.06], including when observed independently in each individual study. Haplotypes within linkage blocks of RXRA support an approximately 30% reduction in odds of metachronous neoplasia arising in the proximal colon among carriers of specific haplotypes, which was strongest (OR(proximal), 0.67; 95% CI, 0.52-0.86) for carriers of a CGGGCA haplotype (rs1805352, rs3132297, rs3132296, rs3118529, rs3118536, and rs7861779). Our results indicate that allelic variation in RXRA affects metachronous colorectal neoplasia, perhaps of particular importance in the development of proximal lesions.
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Affiliation(s)
- Jan B Egan
- Arizona Cancer Center, University of Arizona and Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona 85724-5024, USA
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87
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Beildeck ME, Gelmann EP, Byers SW. Cross-regulation of signaling pathways: an example of nuclear hormone receptors and the canonical Wnt pathway. Exp Cell Res 2010; 316:1763-72. [PMID: 20138864 DOI: 10.1016/j.yexcr.2010.02.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 12/24/2022]
Abstract
Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.
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Affiliation(s)
- Marcy E Beildeck
- Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057, USA
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88
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Sharov AA, Mardaryev AN, Sharova TY, Grachtchouk M, Atoyan R, Byers HR, Seykora JT, Overbeek P, Dlugosz A, Botchkarev VA. Bone morphogenetic protein antagonist noggin promotes skin tumorigenesis via stimulation of the Wnt and Shh signaling pathways. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1303-14. [PMID: 19700758 DOI: 10.2353/ajpath.2009.090163] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofolliculoma. Global gene expression profiles revealed that in contrast to anagen hair follicles of wild-type mice, tumors of transgenic mice showed stage-dependent increases in the expression of genes encoding the selected components of Wnt and Shh pathways. Specifically, expression of the Wnt ligands increased at the initiation stage of tumor formation, whereas expression of the Wnt antagonist and tumor suppressor Wnt inhibitory factor-1 decreased, as compared with fully developed tumors. In contrast, expression of the components of Shh pathway increased in fully developed tumors, as compared with the tumor placodes. Consistent with the expression data, pharmacological treatment of transgenic mice with Wnt and Shh antagonists resulted in the stage-dependent inhibition of tumor initiation, and progression, respectively. Furthermore, BMP signaling stimulated Wnt inhibitory factor-1 expression and promoter activity in cultured tumor cells and HaCaT keratinocytes, as well as inhibited Shh expression, as compared with the corresponding controls. Thus, tumor suppressor activity of the BMPs in skin epithelium depends on the local concentrations of noggin and is mediated at least in part via stage-dependent antagonizing of Wnt and Shh signaling pathways.
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Affiliation(s)
- Andrey A Sharov
- Centre for Skin Sciences, School of Life Sciences, University of Bradford, Bradford, UK
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89
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Abstract
Hair is a primary characteristic of mammals, and exerts a wide range of functions including thermoregulation, physical protection, sensory activity, and social interactions. The hair shaft consists of terminally differentiated keratinocytes that are produced by the hair follicle. Hair follicle development takes place during fetal skin development and relies on tightly regulated ectodermal-mesodermal interactions. After birth, mature and actively growing hair follicles eventually become anchored in the subcutis, and periodically regenerate by spontaneously undergoing repetitive cycles of growth (anagen), apoptosis-driven regression (catagen), and relative quiescence (telogen). Our molecular understanding of hair follicle biology relies heavily on mouse mutants with abnormalities in hair structure, growth, and/or pigmentation. These mice have allowed novel insights into important general molecular and cellular processes beyond skin and hair biology, ranging from organ induction, morphogenesis and regeneration, to pigment and stem cell biology, cell proliferation, migration and apoptosis. In this review, we present basic concepts of hair follicle biology and summarize important recent advances in the field.
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Affiliation(s)
- Marlon R Schneider
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Munich, Germany.
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90
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Ramot Y, Paus R, Tiede S, Zlotogorski A. Endocrine controls of keratin expression. Bioessays 2009; 31:389-99. [DOI: 10.1002/bies.200800121] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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91
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92
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Abstract
CONTEXT Vitamin D receptors are found in most tissues, not just those participating in the classic actions of vitamin D such as bone, gut, and kidney. These nonclassic tissues are therefore potential targets for the active metabolite of vitamin D, 1,25(OH)(2)D. Furthermore, many of these tissues also contain the enzyme CYP27B1 capable of producing 1,25(OH)(2)D from the circulating form of vitamin D. This review was intended to highlight the actions of 1,25(OH)(2)D in several of these tissues but starts with a review of vitamin D production, metabolism, and molecular mechanism. EVIDENCE ACQUISITION Medline was searched for articles describing actions of 1,25(OH)(2)D on parathyroid hormone and insulin secretion, immune responses, keratinocytes, and cancer. EVIDENCE SYNTHESIS Vitamin D production in the skin provides an efficient source of vitamin D. Subsequent metabolism to 1,25(OH)(2)D within nonrenal tissues differs from that in the kidney. Although vitamin D receptor mediates the actions of 1,25(OH)(2)D, regulation of transcriptional activity is cell specific. 1,25(OH)(2)D inhibits PTH secretion but promotes insulin secretion, inhibits adaptive immunity but promotes innate immunity, and inhibits cell proliferation but stimulates their differentiation. CONCLUSIONS The nonclassic actions of vitamin D are cell specific and provide a number of potential new clinical applications for 1,25(OH)(2)D(3) and its analogs. However, the use of vitamin D metabolites and analogs for these applications remains limited by the classic actions of vitamin D leading to hypercalcemia and hypercalcuria.
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Affiliation(s)
- Daniel Bikle
- Veterans Affairs Medical Center (111N), 4150 Clement Street, San Francisco, California 94121, USA.
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93
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Vitamin D Receptor, UVR, and Skin Cancer: A Potential Protective Mechanism. J Invest Dermatol 2008; 128:2357-61. [DOI: 10.1038/jid.2008.249] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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94
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Collins CA, Watt FM. Dynamic regulation of retinoic acid-binding proteins in developing, adult and neoplastic skin reveals roles for beta-catenin and Notch signalling. Dev Biol 2008; 324:55-67. [PMID: 18805411 DOI: 10.1016/j.ydbio.2008.08.034] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 08/26/2008] [Accepted: 08/29/2008] [Indexed: 10/21/2022]
Abstract
Retinoic acid (RA) signalling is essential for epidermal differentiation; however, the mechanisms by which it acts are largely unexplored. Partitioning of RA between different nuclear receptors is regulated by RA-binding proteins. We show that cellular RA-binding proteins CRABP1 and CRABP2 and the fatty acid-binding protein FABP5 are dynamically expressed during skin development and in adult tissue. CRABP1 is expressed in embryonic dermis and in the stroma of skin tumours, but confined to the hair follicle dermal papilla in normal postnatal skin. CRABP2 and FABP5 are expressed in the differentiating cells of sebaceous gland, interfollicular epidermis and hair follicles, with FABP5 being a prominent marker of sebaceous glands and anagen follicle bulbs. All three proteins are upregulated in response to RA treatment or Notch activation and are negatively regulated by Wnt/beta-catenin signalling. Ectopic follicles induced by beta-catenin arise from areas of the sebaceous gland that have lost CRABP2 and FABP5; conversely, inhibition of hair follicle formation by N-terminally truncated Lef1 results in upregulation of CRABP2 and FABP5. Our findings demonstrate that there is dynamic regulation of RA signalling in different regions of the skin and provide evidence for interactions between the RA, beta-catenin and Notch pathways.
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Affiliation(s)
- Charlotte A Collins
- Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
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95
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Paus R, Arck P, Tiede S. (Neuro-)endocrinology of epithelial hair follicle stem cells. Mol Cell Endocrinol 2008; 288:38-51. [PMID: 18423849 DOI: 10.1016/j.mce.2008.02.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 02/26/2008] [Accepted: 02/26/2008] [Indexed: 12/17/2022]
Abstract
The hair follicle is a repository of different types of somatic stem cells. However, even though the hair follicle is both a prominent target organ and a potent, non-classical site of production and/or metabolism of numerous polypetide- and steroid hormones, neuropeptides, neurotransmitters and neurotrophins, the (neuro-)endocrine controls of hair follicle epithelial stem cell (HFeSC) biology remain to be systematically explored. Focussing on HFeSCs, we attempt here to offer a "roadmap through terra incognita" by listing key open questions, by exploring endocrinologically relevant HFeSC gene profiling and mouse genomics data, and by sketching several clinically relevant pathways via which systemic and/or locally generated (neuro-)endocrine signals might impact on HFeSC. Exemplarily, we discuss, e.g. the potential roles of glucocorticoid and vitamin D receptors, the hairless gene product, thymic hormones, bone morphogenic proteins (BMPs) and their antagonists, and Skg-3 in HFeSC biology. Furthermore, we elaborate on the potential role of nerve growth factor (NGF) and substance P-dependent neurogenic inflammation in HFeSC damage, and explore how neuroendocrine signals may influence the balance between maintenance and destruction of hair follicle immune privilege, which protects these stem cells and their progeny. These considerations call for a concerted research effort to dissect the (neuro-)endocrinology of HFeSCs much more systematically than before.
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Affiliation(s)
- Ralf Paus
- Department of Dermatology, University of Lübeck, Lübeck, Germany.
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