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An Isochroman Analog of CD3254 and Allyl-, Isochroman-Analogs of NEt-TMN Prove to Be More Potent Retinoid-X-Receptor (RXR) Selective Agonists Than Bexarotene. Int J Mol Sci 2022; 23:ijms232416213. [PMID: 36555852 PMCID: PMC9782500 DOI: 10.3390/ijms232416213] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 12/09/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Bexarotene is an FDA-approved drug for the treatment of cutaneous T-cell lymphoma (CTCL); however, its use provokes or disrupts other retinoid-X-receptor (RXR)-dependent nuclear receptor pathways and thereby incites side effects including hypothyroidism and raised triglycerides. Two novel bexarotene analogs, as well as three unique CD3254 analogs and thirteen novel NEt-TMN analogs, were synthesized and characterized for their ability to induce RXR agonism in comparison to bexarotene (1). Several analogs in all three groups possessed an isochroman ring substitution for the bexarotene aliphatic group. Analogs were modeled for RXR binding affinity, and EC50 as well as IC50 values were established for all analogs in a KMT2A-MLLT3 leukemia cell line. All analogs were assessed for liver-X-receptor (LXR) activity in an LXRE system to gauge the potential for the compounds to provoke raised triglycerides by increasing LXR activity, as well as to drive LXRE-mediated transcription of brain ApoE expression as a marker for potential therapeutic use in neurodegenerative disorders. Preliminary results suggest these compounds display a broad spectrum of off-target activities. However, many of the novel compounds were observed to be more potent than 1. While some RXR agonists cross-signal the retinoic acid receptor (RAR), many of the rexinoids in this work displayed reduced RAR activity. The isochroman group did not appear to substantially reduce RXR activity on its own. The results of this study reveal that modifying potent, selective rexinoids like bexarotene, CD3254, and NEt-TMN can provide rexinoids with increased RXR selectivity, decreased potential for cross-signaling, and improved anti-proliferative characteristics in leukemia models compared to 1.
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Jurutka PW, di Martino O, Reshi S, Mallick S, Sabir ZL, Staniszewski LJP, Warda A, Maiorella EL, Minasian A, Davidson J, Ibrahim SJ, Raban S, Haddad D, Khamisi M, Suban SL, Dawson BJ, Candia R, Ziller JW, Lee MY, Liu C, Liu W, Marshall PA, Welch JS, Wagner CE. Modeling, Synthesis, and Biological Evaluation of Potential Retinoid-X-Receptor (RXR) Selective Agonists: Analogs of 4-[1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahyro-2-naphthyl)ethynyl]benzoic Acid (Bexarotene) and 6-(Ethyl(4-isobutoxy-3-isopropylphenyl)amino)nicotinic Acid (NEt-4IB). Int J Mol Sci 2021; 22:ijms222212371. [PMID: 34830251 PMCID: PMC8624485 DOI: 10.3390/ijms222212371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/05/2022] Open
Abstract
Five novel analogs of 6-(ethyl)(4-isobutoxy-3-isopropylphenyl)amino)nicotinic acid—or NEt-4IB—in addition to seven novel analogs of 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) were prepared and evaluated for selective retinoid-X-receptor (RXR) agonism alongside bexarotene (1), a FDA-approved drug for cutaneous T-cell lymphoma (CTCL). Bexarotene treatment elicits side-effects by provoking or disrupting other RXR-dependent pathways. Analogs were assessed by the modeling of binding to RXR and then evaluated in a human cell-based RXR-RXR mammalian-2-hybrid (M2H) system as well as a RXRE-controlled transcriptional system. The analogs were also tested in KMT2A-MLLT3 leukemia cells and the EC50 and IC50 values were determined for these compounds. Moreover, the analogs were assessed for activation of LXR in an LXRE system as drivers of ApoE expression and subsequent use as potential therapeutics in neurodegenerative disorders, and the results revealed that these compounds exerted a range of differential LXR-RXR activation and selectivity. Furthermore, several of the novel analogs in this study exhibited reduced RARE cross-signaling, implying RXR selectivity. These results demonstrate that modification of partial agonists such as NEt-4IB and potent rexinoids such as bexarotene can lead to compounds with improved RXR selectivity, decreased cross-signaling of other RXR-dependent nuclear receptors, increased LXRE-heterodimer selectivity, and enhanced anti-proliferative potential in leukemia cell lines compared to therapeutics such as 1.
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Affiliation(s)
- Peter W. Jurutka
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
- Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Orsola di Martino
- Department of Internal Medicine, Washington University, St. Louis, MO 63110, USA; (O.d.M.); (J.S.W.)
| | - Sabeeha Reshi
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Sanchita Mallick
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Zhela L. Sabir
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Lech J. P. Staniszewski
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Ankedo Warda
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
- Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - Emma L. Maiorella
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Ani Minasian
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Jesse Davidson
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Samir J. Ibrahim
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - San Raban
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Dena Haddad
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Madleen Khamisi
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Stephanie L. Suban
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Bradley J. Dawson
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Riley Candia
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - Joseph W. Ziller
- Department of Chemistry, University of California, Irvine, CA 92697, USA;
| | - Ming-Yue Lee
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85201, USA; (M.-Y.L.); (C.L.); (W.L.)
| | - Chang Liu
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85201, USA; (M.-Y.L.); (C.L.); (W.L.)
| | - Wei Liu
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85201, USA; (M.-Y.L.); (C.L.); (W.L.)
| | - Pamela A. Marshall
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
| | - John S. Welch
- Department of Internal Medicine, Washington University, St. Louis, MO 63110, USA; (O.d.M.); (J.S.W.)
| | - Carl E. Wagner
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306, USA; (P.W.J.); (S.R.); (S.M.); (Z.L.S.); (L.J.P.S.); (A.W.); (E.L.M.); (A.M.); (J.D.); (S.J.I.); (S.R.); (D.H.); (M.K.); (S.L.S.); (B.J.D.); (R.C.); (P.A.M.)
- Correspondence: ; Tel.: +1-602-543-6937
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Evolving Role of Vitamin D in Immune-Mediated Disease and Its Implications in Autoimmune Hepatitis. Dig Dis Sci 2019; 64:324-344. [PMID: 30370494 DOI: 10.1007/s10620-018-5351-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/09/2018] [Indexed: 12/11/2022]
Abstract
Vitamin D has immunomodulatory, anti-inflammatory, antioxidant, and anti-fibrotic actions that may impact on the occurrence and outcome of immune-mediated disease. The goals of this review are to describe the nature of these expanded roles, examine the implications of vitamin D deficiency in autoimmune hepatitis, and identify opportunities for future investigation. Abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Vitamin D receptors are expressed on the principal cell populations involved in the innate and adaptive immune responses. Macrophages and dendritic cells can produce 1,25-dihydroxyvitamin D within the microenvironment. This active form of vitamin D can inhibit immune cell proliferation, promote an anti-inflammatory cytokine profile, expand regulatory T cells, enhance glucocorticoid actions, increase glutathione production, and inhibit hepatic stellate cells. Vitamin D deficiency has been commonly present in patients with immune-mediated liver and non-liver diseases, and it has been associated with histological severity, advanced hepatic fibrosis, and non-response to conventional glucocorticoid therapy in autoimmune hepatitis. Vitamin D analogues with high potency, low calcemic effects, and independence from hepatic hydroxylation are possible interventions. In conclusion, vitamin D has properties that could ameliorate immune-mediated disease, and vitamin D deficiency has been a common finding in immune-mediated liver and non-liver diseases, including autoimmune hepatitis. Loss of vitamin D-dependent homeostatic mechanisms may promote disease progression. Vitamin D analogues that are independent of hepatic hydroxylation constitute an investigational opportunity to supplement current management of autoimmune hepatitis.
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Zhang Z, Chen F, Li J, Luo F, Hou T, Xu J, Sun D. 1,25(OH) 2D 3 suppresses proinflammatory responses by inhibiting Th1 cell differentiation and cytokine production through the JAK/STAT pathway. Am J Transl Res 2018; 10:2737-2746. [PMID: 30210711 PMCID: PMC6129541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
1,25(OH)2D3 is an immune modulation hormone with beneficial effects on T cell- mediated autoimmune diseases. The purpose of the present study is to investigate the direct effects of vitamin D on Bacillus Calmette Guerin (BCG)-infected CD4+ T cells in both VDR-deficient (VDR-/-) mice and wild type (WT) mice. Specifically, we aimed to investigate the effect of vitamin D on Th1 cells and elucidate the underlying molecular mechanism. Naïve CD4 T cells were purified from VDR-/- mice and WT mice to induce Th1 cells and were activated by BCG. Th1 cell differentiation and cytokine production in vitro were inhibited by 10 nM 1,25(OH)2D3. The JAK/STAT pathway was activated by 1,25(OH)2D3 addition in both VDR-/- and wild type T cells. In vivo, a vitamin D-deficiency VDR-/- and WT mouse model was established and the mice were vaccinated with BCG. An ELISA assay was performed to measure the levels of VD, IL-2, IFN-γ and TNF-β in the blood, and flow cytometry was used to analyze the proportion of Th1 and Th2 cells in the spleen. 1,25(OH)2D3 affected Th cells polarization by inhibiting Th1 and augmenting Th2 cell development in the vitamin D-deficiency mouse model. Moreover, 1,25(OH)2D3 inhibited the inflammatory infiltrates and expression of IL-2, IFN-γ and TNF-β in the spleen of vitamin D-deficient mice following vaccination with BCG. These findings suggested that 1,25(OH)2D3 suppressed the inflammatory response by inhibiting Th1 cell differentiation and cytokine production by the JAK/STAT pathway.
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Affiliation(s)
- Zehua Zhang
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
| | - Feifan Chen
- Emergency Room, The First Affiliated Hospital, Zhengzhou UniversityHenan, China
| | - Jianhua Li
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
| | - Fei Luo
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
| | - Tianyong Hou
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
| | - Jianzhong Xu
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
| | - Dong Sun
- Department of Orthopedics, Southwest Hospital, Third Military Medical UniversityChongqing, China
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Hanish BJ, Hackney Price JF, Kaneko I, Ma N, van der Vaart A, Wagner CE, Jurutka PW, Marshall PA. A novel gene expression analytics-based approach to structure aided design of rexinoids for development as next-generation cancer therapeutics. Steroids 2018; 135:36-49. [PMID: 29704526 PMCID: PMC5977990 DOI: 10.1016/j.steroids.2018.04.009] [Citation(s) in RCA: 7] [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: 02/09/2018] [Revised: 04/09/2018] [Accepted: 04/18/2018] [Indexed: 12/20/2022]
Abstract
Rexinoids are powerful ligands that bind to retinoid-X-receptors (RXRs) and show great promise as therapeutics for a wide range of diseases, including cancer. However, only one rexinoid, bexarotene (Targretin TM) has been successfully transitioned from the bench to the clinic and used to treat cutaneous T-cell lymphoma (CTCL). Our goal is to develop novel potent rexinoids with a less untoward side effect profile than bexarotene. To this end, we have synthesized a wide array of rexinoids with EC50 values and biological activity similar to bexarotene. In order to determine their suitability for additional downstream analysis, and to identify potential candidate analogs for clinical translation, we treated human CTCL cells in culture and employed microarray technology to assess gene expression profiles. We analyzed twelve rexinoids and found they could be stratified into three distinct categories based on their gene expression: similar to bexarotene, moderately different from bexarotene, and substantially different from bexarotene. Surprisingly, small changes in the structure of the bexarotene parent compound led to marked differences in gene expression profiles. Furthermore, specific analogs diverged markedly from our hypothesis in expression of genes expected to be important for therapeutic promise. However, promoter analysis of genes whose expression was analyzed indicates general regulatory trends along structural frameworks. Our results suggest that certain structural motifs, particularly the basic frameworks found in analog 4 and analog 9, represent important starting points to exploit in generating additional rexinoids for future study and therapeutic applications.
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Affiliation(s)
- Bentley J Hanish
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States
| | - Jennifer F Hackney Price
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States
| | - Ichiro Kaneko
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States; University of Arizona College of Medicine-Phoenix, Department of Basic Medical Sciences, Phoenix, AZ, United States; Department of Molecular Nutrition, Institution of Health Bioscience, University of Tokushima Graduate School, Kuramoto-cho, Japan
| | - Ning Ma
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Arjan van der Vaart
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Carl E Wagner
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States
| | - Peter W Jurutka
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States; University of Arizona College of Medicine-Phoenix, Department of Basic Medical Sciences, Phoenix, AZ, United States; University of Arizona Cancer Center, Tucson, AZ, United States
| | - Pamela A Marshall
- New College of Interdisciplinary Arts and Sciences, Arizona State University, Glendale, AZ, United States.
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Heck MC, Wagner CE, Shahani PH, MacNeill M, Grozic A, Darwaiz T, Shimabuku M, Deans DG, Robinson NM, Salama SH, Ziller JW, Ma N, van der Vaart A, Marshall PA, Jurutka PW. Modeling, Synthesis, and Biological Evaluation of Potential Retinoid X Receptor (RXR)-Selective Agonists: Analogues of 4-[1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic Acid (Bexarotene) and 6-(Ethyl(5,5,8,8-tetrahydronaphthalen-2-yl)amino)nicotinic Acid (NEt-TMN). J Med Chem 2016; 59:8924-8940. [DOI: 10.1021/acs.jmedchem.6b00812] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Michael C. Heck
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Carl E. Wagner
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Pritika H. Shahani
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Mairi MacNeill
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Aleksandra Grozic
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Tamana Darwaiz
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Micah Shimabuku
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - David G. Deans
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Nathan M. Robinson
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Samer H. Salama
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Joseph W. Ziller
- Department
of Chemistry, University of California, Irvine, 576 Rowland Hall, Irvine, California 92697, United States
| | - Ning Ma
- Department
of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE 205, Tampa, Florida 33620, United States
| | - Arjan van der Vaart
- Department
of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE 205, Tampa, Florida 33620, United States
| | - Pamela A. Marshall
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
| | - Peter W. Jurutka
- School
of Mathematical and Natural Sciences, New College of Interdisciplinary
Arts and Sciences, Arizona State University, 4701 West Thunderbird Road, Glendale, Arizona 85306, United States
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Marshall PA, Jurutka PW, Wagner CE, van der Vaart A, Kaneko I, Chavez PI, Ma N, Bhogal JS, Shahani P, Swierski JC, MacNeill M. Analysis of differential secondary effects of novel rexinoids: select rexinoid X receptor ligands demonstrate differentiated side effect profiles. Pharmacol Res Perspect 2015; 3:e00122. [PMID: 26038698 PMCID: PMC4448986 DOI: 10.1002/prp2.122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/28/2014] [Accepted: 12/15/2014] [Indexed: 11/21/2022] Open
Abstract
In order to determine the feasibility of utilizing novel rexinoids for chemotherapeutics and as potential treatments for neurological conditions, we undertook an assessment of the side effect profile of select rexinoid X receptor (RXR) analogs that we reported previously. We assessed pharmacokinetic profiles, lipid and thyroid-stimulating hormone (TSH) levels in rats, and cell culture activity of rexinoids in sterol regulatory element-binding protein (SREBP) induction and thyroid hormone inhibition assays. We also performed RNA sequencing of the brain tissues of rats that had been dosed with the compounds. We show here for the first time that potent rexinoid activity can be uncoupled from drastic lipid changes and thyroid axis variations, and we propose that rexinoids can be developed with improved side effect profiles than the parent compound, bexarotene (1).
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Affiliation(s)
- Pamela A Marshall
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Peter W Jurutka
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Carl E Wagner
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Arjan van der Vaart
- Department of Chemistry, University of South Florida 4202 E Fowler Ave CHE 205, Tampa, Florida, 33620
| | - Ichiro Kaneko
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Pedro I Chavez
- Biomedical Sciences Program, Midwestern University 19555 N 59th Ave., Glendale, Arizona, 86308
| | - Ning Ma
- Department of Chemistry, University of South Florida 4202 E Fowler Ave CHE 205, Tampa, Florida, 33620
| | - Jaskaran S Bhogal
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Pritika Shahani
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Johnathon C Swierski
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
| | - Mairi MacNeill
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University 4701 W Thunderbird Rd, Glendale, Arizona, 85306
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8
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Jurutka PW, Kaneko I, Yang J, Bhogal JS, Swierski JC, Tabacaru CR, Montano LA, Huynh CC, Jama RA, Mahelona RD, Sarnowski JT, Marcus LM, Quezada A, Lemming B, Tedesco MA, Fischer AJ, Mohamed SA, Ziller JW, Ma N, Gray GM, van der Vaart A, Marshall PA, Wagner CE. Modeling, synthesis, and biological evaluation of potential retinoid X receptor (RXR) selective agonists: novel analogues of 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) and (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254). J Med Chem 2013; 56:8432-54. [PMID: 24180745 PMCID: PMC3916150 DOI: 10.1021/jm4008517] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Three unreported analogues of 4-[1-(3,5,5,8,8-pentamethyl-5-6-7-8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (1), otherwise known as bexarotene, as well as four novel analogues of (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254), are described and evaluated for their retinoid X receptor (RXR) selective agonism. Compound 1 has FDA approval as a treatment for cutaneous T-cell lymphoma (CTCL), although treatment with 1 can elicit side-effects by disrupting other RXR-heterodimer receptor pathways. Of the seven modeled novel compounds, all analogues stimulate RXR-regulated transcription in mammalian 2 hybrid and RXRE-mediated assays, possess comparable or elevated biological activity based on EC50 profiles, and retain similar or improved apoptotic activity in CTCL assays compared to 1. All novel compounds demonstrate selectivity for RXR and minimal crossover onto the retinoic acid receptor (RAR) compared to all-trans-retinoic acid, with select analogues also reducing inhibition of other RXR-dependent pathways (e.g., VDR-RXR). Our results demonstrate that further improvements in biological potency and selectivity of bexarotene can be achieved through rational drug design.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Joseph W. Ziller
- Department of Chemistry, University of California, Irvine, 576 Rowland Hall, Irvine, CA 92697
| | - Ning Ma
- Department of Chemistry, University of South Florida, 4202 E Fowler Ave, CHE 205, Tampa, FL, 33620
| | - Geoffrey M. Gray
- Department of Chemistry, University of South Florida, 4202 E Fowler Ave, CHE 205, Tampa, FL, 33620
| | - Arjan van der Vaart
- Department of Chemistry, University of South Florida, 4202 E Fowler Ave, CHE 205, Tampa, FL, 33620
| | | | - Carl E. Wagner
- Corresponding author: School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University, 4701 W. Thunderbird Road, Glendale, AZ 85306. Tele: (602) 543-6937. Fax: (6020 543-6073.
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9
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Chow ECY, Quach HP, Vieth R, Pang KS. Temporal changes in tissue 1α,25-dihydroxyvitamin D3, vitamin D receptor target genes, and calcium and PTH levels after 1,25(OH)2D3 treatment in mice. Am J Physiol Endocrinol Metab 2013; 304:E977-89. [PMID: 23482451 DOI: 10.1152/ajpendo.00489.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The vitamin D receptor (VDR) maintains a balance of plasma calcium and 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], its natural active ligand, by directly regulating the calcium ion channel (TRPV6) and degradation enzyme (CYP24A1), and indirectly regulating the parathyroid hormone (PTH) for feedback regulation of the synthetic enzyme CYP27B1. Studies that examined the intricate relationships between plasma and tissue 1,25(OH)2D3 levels and changes in VDR target genes and plasma calcium and PTH are virtually nonexistent. In this study, we investigated temporal correlations between tissue 1,25(OH)2D3 concentrations and VDR target genes in ileum and kidney and plasma calcium and PTH concentrations in response to 1,25(OH)2D3 treatment in mice (2.5 μg/kg ip, singly or q2d × 4). After a single ip dose, plasma 1,25(OH)2D3 peaked at ∼0.5 h and then decayed biexponentially, falling below basal levels after 24 h and then returning to baseline after 8 days. Upon repetitive ip dosing, plasma, ileal, renal, and bone 1,25(OH)2D3 concentrations rose and decayed in unison. Temporal profiles showed increased expressions of ileal Cyp24a1 and renal Cyp24a1, Mdr1/P-gp, and VDR but decreased renal Cyp27b1 mRNA after a time delay in VDR activation. Increased plasma calcium and attenuated PTH levels and increased ileal and renal Trpv6 expression paralleled the changes in tissue 1,25(OH)2D3 concentrations. Gene changes in the kidney were more sustained than those in intestine, but the magnitudes of change for Cyp24a1 and Trpv6 were lower than those in intestine. The data revealed that 1,25(OH)2D3 equilibrates with tissues rapidly, and VDR target genes respond quickly to exogenously administered 1,25(OH)2D3.
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Affiliation(s)
- Edwin C Y Chow
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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10
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Rid R, Wagner M, Maier CJ, Hundsberger H, Hintner H, Bauer JW, Onder K. Deciphering the calcitriol-induced transcriptomic response in keratinocytes: presentation of novel target genes. J Mol Endocrinol 2013; 50:131-49. [PMID: 23256991 DOI: 10.1530/jme-11-0191] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Numerous studies to date have been aimed at unraveling the large suite of calcitriol (1α,25-dihydroxyvitamin D(3)) response genes in diverse tissues including skin, where this hormone is involved in regulating keratinocyte proliferation, differentiation, permeability barrier formation, innate immunity promotion, antimicrobial peptide production, and wound healing. However, the various approaches differ considerably in probed cell types, scale, throughput, and statistical reliability and do, of note, not reveal much overlap. To further expand our knowledge on presently elusive targets and characterize the extent of fragmentation of existing datasets, we have performed whole-transcriptome microarray examinations of calcitriol-treated human primary keratinocytes. Out of 28,869 genes investigated, we uncovered 86 differentially expressed (67 upregulated and 19 downregulated) candidates that were functionally clustered into five annotation categories: response to wounding, protease inhibition, secondary metabolite biosynthesis, cellular migration, and amine biosynthetic processes. A complementary RTq-PCR study of 78 nominees selected thereof demonstrated significant differential expression of 55 genes (48 upregulated and seven downregulated) within biological replicates. Our hit list contains nine previously authenticated targets (16.36%, proof of concept) and 46 novel genes (83.6%) that have not yet been explicitly described as being differentially regulated within human primary keratinocytes. Direct vitamin D receptor response element predictions within the regulatory promoter regions of 50 of the RTq-PCR-validated targets agreed with known biological functionality and corroborated our stringent data validation pipeline. Altogether, our results indicate the value of continuing these kinds of gene expression studies, which contribute to an enhanced comprehension of calcitriol-mediated processes that may be dysregulated in human skin pathophysiology.
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Affiliation(s)
- Raphaela Rid
- Division of Molecular Dermatology, Department of Dermatology, Paracelsus Private Medical University Salzburg, Salzburg, Austria
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11
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Aoi N, Inoue K, Chikanishi T, Fujiki R, Yamamoto H, Kato H, Eto H, Doi K, Itami S, Kato S, Yoshimura K. 1α,25-dihydroxyvitamin D3 modulates the hair-inductive capacity of dermal papilla cells: therapeutic potential for hair regeneration. Stem Cells Transl Med 2012. [PMID: 23197867 DOI: 10.5966/sctm.2012-0032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dermal papilla cells (DPCs) have the potential to induce differentiation of epithelial stem cells into hair, and Wnt signaling is deeply involved in the initiation process. The functional limitation of expanded adult DPCs has been a difficult challenge for cell-based hair regrowth therapy. We previously reported that 1α,25-dihydroxyvitamin D(3) (VD(3)) upregulates expression of transforming growth factor (TGF)-β2 and alkaline phosphatase (ALP) activity, both features of hair-inducing human DPCs (hDPCs). In this study, we further examined the effects and signaling pathways associated with VD(3) actions on DPCs. VD(3) suppressed hDPC proliferation in a dose-dependent, noncytotoxic manner. Among the Wnt-related genes investigated, Wnt10b expression was significantly upregulated by VD(3) in hDPCs. Wnt10b upregulation, as well as upregulation of ALPL (ALP, liver/bone/kidney) and TGF-β2, by VD(3) was specific in hDPCs and not detected in human dermal fibroblasts. Screening of paracrine or endocrine factors in the skin indicated that all-trans retinoic acid (atRA) upregulated Wnt10b gene expression, although synergistic upregulation (combined atRA and VD(3)) was not seen. RNA interference with vitamin D receptor (VDR) revealed that VD(3) upregulation of Wnt10b, ALPL, and TGF-β2 was mediated through the genomic VDR pathway. In a rat model of de novo hair regeneration by murine DPC transplantation, pretreatment with VD(3) significantly enhanced hair folliculogenesis. Specifically, a greater number of outgrowing hair shafts and higher maturation of regenerated follicles were observed. Together, these data suggest that VD(3) may promote functional differentiation of DPCs and be useful in preserving the hair follicle-inductive capacity of cultured DPCs for hair regeneration therapies.
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Affiliation(s)
- Noriyuki Aoi
- Department of Plastic Surgery, University of Tokyo, Tokyo, Japan
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12
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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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13
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Choi M, Yamada S, Makishima M. Dynamic and ligand-selective interactions of vitamin D receptor with retinoid X receptor and cofactors in living cells. Mol Pharmacol 2011; 80:1147-55. [PMID: 21917910 DOI: 10.1124/mol.111.074138] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The vitamin D receptor (VDR) mediates vitamin D signaling in numerous physiological and pharmacological processes, including bone and calcium metabolism, cellular growth and differentiation, immunity, and cardiovascular function. Although transcriptional regulation by VDR has been investigated intensively, an understanding of ligand-selective dynamic VDR conformations remains elusive. Here, we examined ligand-dependent dynamic interactions of VDR with retinoid X receptor (RXR), steroid receptor coactivator 1 (SRC-1), and silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) in cells using fluorescence resonance energy transfer (FRET) and chromatin immunoprecipitation (ChIP) assays. We compared the effects of 1α,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], lithocholic acid (LCA), and (25R)-25-adamantyl-1α,25-dihydroxy-2-methylene-22,23-didehydro-19,26,27-trinor-20-epivitamin D(3) (ADTT), a partial agonist/antagonist vitamin D derivative. In the absence of ligand, VDR homodimers were preferred to RXR heterodimers and were associated with SMRT. 1,25(OH)(2)D(3) induced heterodimerization with RXR, dissociation of SMRT, and association of SRC-1. LCA and ADTT induced those effects to a lesser extent at concentrations that did not induce expression of the VDR target gene CYP24A1 in human embryonic kidney (HEK) 293 cells. Unlike in HEK293 cells, ADTT increased CYP24A1 expression in HCT116 cells and increased the association of VDR and SMRT on the CYP24A1 promoter. The results indicate that ligand-selective conformation may lead to unique cofactor complex formation in a cell context-dependent manner. The combination of FRET and ChIP assays is a powerful tool useful in understanding ligand-selective dynamic VDR conformations and the development of selective VDR modulators.
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Affiliation(s)
- Mihwa Choi
- Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, Japan
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14
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Floyd ZE, Zvonic S, E. Nuttall M, M. Gimble J. Fine-Tuning Reception in the Bone: PPARgamma and Company. PPAR Res 2011; 2006:52950. [PMID: 17259665 PMCID: PMC1779576 DOI: 10.1155/ppar/2006/52950] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 06/19/2006] [Accepted: 06/26/2006] [Indexed: 12/17/2022] Open
Abstract
PPARgamma plays a central role in the formation of fat. Regulation of PPARgamma activity depends on numerous factors ranging from dietary ligands to nuclear hormone coactivators and corepressors to oxygen-sensing mechanisms. In addition, the interplay of PPARgamma with other nuclear hormone receptors has implications for the balance between adipogenesis and osteogenesis in mesenchymal stem cells of the bone marrow stroma. This review will explore a range of factors influencing PPARgamma activity and how these interactions may affect osteogenesis.
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Affiliation(s)
- Z. Elizabeth Floyd
- Stem Cell Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
- *Z. Elizabeth Floyd:
| | - Sanjin Zvonic
- Stem Cell Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | | | - Jeffrey M. Gimble
- Stem Cell Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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15
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DNA binding alters coactivator interaction surfaces of the intact VDR-RXR complex. Nat Struct Mol Biol 2011; 18:556-63. [PMID: 21478866 PMCID: PMC3087838 DOI: 10.1038/nsmb.2046] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 01/28/2011] [Indexed: 12/04/2022]
Abstract
The vitamin D receptor (VDR) functions as an obligate heterodimer with the retinoid X receptor (RXR). These nuclear receptors (NRs) are multidomain proteins and it is unclear how various domains interact with one another within the NR heterodimer. Here we show that binding of intact heterodimer to DNA alters the receptor dynamics in regions remote from the DNA binding domains (DBDs), including the coactivator binding surfaces of both coreceptors, and the sequence of the DNA response element can specify the dynamics. Furthermore, agonist binding to the heterodimer results in changes in the stability of the VDR DBD, indicating that ligand itself may play a role in DNA recognition. These data suggest a mechanism by which NRs can display promoter-specific activity and impart differential effects on various target genes, which provides mechanistic insight for the function of selective NR modulators.
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16
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Na S, Ma Y, Zhao J, Schmidt C, Zeng QQ, Chandrasekhar S, Chin WW, Nagpal S. A Nonsecosteroidal Vitamin D Receptor Modulator Ameliorates Experimental Autoimmune Encephalomyelitis without Causing Hypercalcemia. Autoimmune Dis 2011; 2011:132958. [PMID: 21318047 PMCID: PMC3034943 DOI: 10.4061/2011/132958] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 12/10/2010] [Accepted: 12/19/2010] [Indexed: 11/21/2022] Open
Abstract
Vitamin D receptor (VDR) agonists are currently the agents of choice for the treatment of psoriasis, a skin inflammatory indication that is believed to involve an autoimmune component. 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], the biologically active metabolite of vitamin D, has shown efficacy in animal autoimmune disease models of multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, and type I diabetes. However, the side effect of 1,25-(OH)2D3 and its synthetic secosteroidal analogs is hypercalcemia, which is a major impediment in their clinical development for autoimmune diseases. Hypercalcemia develops as a result of the action of VDR agonists on the intestine. Here, we describe the identification of a VDR modulator (VDRM) compound A that was transcriptionally less active in intestinal cells and as a result exhibited less calcemic activity in vivo than 1,25-(OH)2D3. Cytokine analysis indicated that the VDRM not only modulated the T-helper cell balance from Th1 to Th2 effector function but also inhibited Th17 differentiation. Finally, we demonstrate that the oral administration of compound A inhibited the induction and progress of experimental autoimmune encephalomyelitis in mice without causing hypercalcemia.
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Affiliation(s)
- Songqing Na
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA
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17
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Artaza JN, Sirad F, Ferrini MG, Norris KC. 1,25(OH)2vitamin D3 inhibits cell proliferation by promoting cell cycle arrest without inducing apoptosis and modifies cell morphology of mesenchymal multipotent cells. J Steroid Biochem Mol Biol 2010; 119:73-83. [PMID: 20064609 PMCID: PMC2828517 DOI: 10.1016/j.jsbmb.2010.01.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 01/02/2010] [Accepted: 01/04/2010] [Indexed: 01/09/2023]
Abstract
The vitamin D receptor (VDR) and its ligand 1,25D play an important role in regulating cell growth and cell fate. We examined the effect of 1,25D on cell morphology, cell proliferation, cell cycle progression and apoptosis on mesenchymal multipotent cells. Multipotent cells were treated with and without 1,25D in a time- and dose-dependent manner. Changes in cell morphology were evaluated by a green fluorescence fluorocrome. Cell proliferation was determined by the Formazan assay and PCNA antigen expression. The expression of genes related to the cell cycle was analyzed by DNA microarrays, RT(2)PCR arrays and western blots. Apoptosis was evaluated by TUNEL assay, and the expression of pro- and anti-apoptotic related genes by RT(2)PCR arrays and western blots. 1,25D inhibited cell proliferation, induced cell cycle arrest, and promoted accumulation of cells in G0/G1 phase without inducing apoptosis. An increase in cell size was associated with a decrease in the GTPase Rho and the atypical Rho family GTPase Rhou/Wrch-1 expression without inducing Wnt-1 expression. Survivin expression was also increased and may represent a novel 1,25D-mediated pathway regulating tissue injury and fibrosis. The data provide a mechanistic explanation for the anti-proliferative and anti-apoptotic properties of 1,25D in mesenchymal multipotent cells.
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Affiliation(s)
- Jorge N Artaza
- Department of Internal Medicine, Charles Drew University of Medicine & Science, Los Angeles, CA 90059, USA.
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18
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Okamura M, Takano Y, Saito Y, Yao J, Kitamura M. Induction of nephrin gene expression by selective cooperation of the retinoic acid receptor and the vitamin D receptor. Nephrol Dial Transplant 2009; 24:3006-12. [DOI: 10.1093/ndt/gfp243] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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19
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Tang J, Zhou R, Luger D, Zhu W, Silver PB, Grajewski RS, Su SB, Chan CC, Adorini L, Caspi RR. Calcitriol suppresses antiretinal autoimmunity through inhibitory effects on the Th17 effector response. THE JOURNAL OF IMMUNOLOGY 2009; 182:4624-32. [PMID: 19342637 DOI: 10.4049/jimmunol.0801543] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Experimental autoimmune uveitis (EAU) serves as a model for human autoimmune uveitis and for cell-mediated autoimmunity in general. EAU induced in mice by immunization with the retinal Ag interphotoreceptor retinoid-binding protein in CFA is driven by the Th17 response. Oral calcitriol (1,25-dihydroxyvitamin D(3)) prevented as well as partly reversed disease and suppressed immunological responses. In vitro, calcitriol directly suppressed IL-17 induction in purified naive CD4(+) T cells without inhibiting Th17 lineage commitment, as reflected by unaltered RORgammat, STAT3, and FoxP3 expression. In contrast, in vivo treatment with calcitriol of mice challenged for EAU impaired commitment to the Th17 lineage, as judged by reduction of both RORgammat and IL-17 in CD4(+) T cells. Innate immune response parameters in draining lymph nodes of treated mice were suppressed, as was production of IL-1, IL-6, TNF-alpha, and IL-12/IL-23p40, but not IL-10, by explanted splenic dendritic cells (DC). Finally, supernatants of calcitriol-conditioned bone marrow-derived DC had reduced ability to support Th17 polarization of naive CD4(+) T cells in vitro and in vivo. Thus, calcitriol appears to suppress autoimmunity by inhibiting the Th17 response at several levels, including the ability of DC to support priming of Th17 cells, the ability of CD4(+) T cells to commit to the Th17 lineage, and the ability of committed Th17 T cells to produce IL-17.
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Affiliation(s)
- Jun Tang
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Xu Y, Iwanaga K, Zhou C, Cheesman MJ, Farin F, Thummel KE. Selective induction of intestinal CYP3A23 by 1alpha,25-dihydroxyvitamin D3 in rats. Biochem Pharmacol 2006; 72:385-92. [PMID: 16769037 DOI: 10.1016/j.bcp.2006.04.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Revised: 04/24/2006] [Accepted: 04/27/2006] [Indexed: 11/19/2022]
Abstract
Enhancement of CYP3A transcription in both the small intestine and liver of the mouse by activation of a VDR signaling pathway was shown recently by Makishima et al. (Science, 2002). However, in humans and rats, hepatic VDR content is much lower than that found in small intestine, suggesting the possibility of tissue-selective responses to 1,25(OH)(2)D(3). The purpose of this study was to determine the effect of 1,25(OH)(2)D(3) on intestinal and hepatic CYP3A expression in the rat. We found that an acute intraperitoneal treatment (every 48 h) in adult male rats with 1,25(OH)(2)D(3) induced CYP3A transcription selectively in small intestine, but not in liver. At a dose of 100 ng, there was a 6.6-fold increase in intestinal CYP3A23 mRNA after the third treatment (p < 0.05). There were concordant effects of 1,25(OH)(2)D(3) treatment on intestinal CYP3A23 protein levels; 2.2-fold (p < 0.05), 3.5-fold (p < 0.05) and 4.8-fold (p < 0.01) increase following 1-3 doses of 100 ng 1,25(OH)(2)D(3), respectively. In contrast, there was no significant change of CYP3A23 protein content in liver at the 1,25(OH)(2)D(3) doses tested. In support of these findings, there was a 366-fold and 77-fold higher level of VDR mRNA expression in the respective rat and human jejunal mucosa, compared to the liver. These data suggest that the human liver will be less sensitive than the intestine to the transcriptional effects of 1,25(OH)(2)D(3) and that this regulatory pathway may contribute to inter-individual variability in constitutive intestinal CYP3A4 expression.
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MESH Headings
- Animals
- Aryl Hydrocarbon Hydroxylases/genetics
- Aryl Hydrocarbon Hydroxylases/metabolism
- Blotting, Western
- Calcitriol/pharmacology
- Cytochrome P-450 CYP3A/genetics
- Cytochrome P-450 CYP3A/metabolism
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Dose-Response Relationship, Drug
- Gene Expression Regulation, Enzymologic/drug effects
- Humans
- Intestinal Mucosa/metabolism
- Intestines/drug effects
- Intestines/enzymology
- Jejunum/drug effects
- Jejunum/enzymology
- Jejunum/metabolism
- Liver/drug effects
- Liver/enzymology
- Liver/metabolism
- Male
- Oxidoreductases, N-Demethylating/genetics
- Oxidoreductases, N-Demethylating/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Steroid Hydroxylases/genetics
- Steroid Hydroxylases/metabolism
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Affiliation(s)
- Yang Xu
- Department of Pharmaceutics, University of Washington, Seattle, 98195-7610, USA
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21
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Ma Y, Khalifa B, Yee YK, Lu J, Memezawa A, Savkur RS, Yamamoto Y, Chintalacharuvu SR, Yamaoka K, Stayrook KR, Bramlett KS, Zeng QQ, Chandrasekhar S, Yu XP, Linebarger JH, Iturria SJ, Burris TP, Kato S, Chin WW, Nagpal S. Identification and characterization of noncalcemic, tissue-selective, nonsecosteroidal vitamin D receptor modulators. J Clin Invest 2006; 116:892-904. [PMID: 16528410 PMCID: PMC1395481 DOI: 10.1172/jci25901] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Accepted: 01/16/2006] [Indexed: 11/17/2022] Open
Abstract
Vitamin D receptor (VDR) ligands are therapeutic agents for the treatment of psoriasis, osteoporosis, and secondary hyperparathyroidism. VDR ligands also show immense potential as therapeutic agents for autoimmune diseases and cancers of skin, prostate, colon, and breast as well as leukemia. However, the major side effect of VDR ligands that limits their expanded use and clinical development is hypercalcemia that develops as a result of the action of these compounds mainly on intestine. In order to discover VDR ligands with less hypercalcemia liability, we sought to identify tissue-selective VDR modulators (VDRMs) that act as agonists in some cell types and lack activity in others. Here, we describe LY2108491 and LY2109866 as nonsecosteroidal VDRMs that function as potent agonists in keratinocytes, osteoblasts, and peripheral blood mononuclear cells but show poor activity in intestinal cells. Finally, these nonsecosteroidal VDRMs were less calcemic in vivo, and LY2108491 exhibited more than 270-fold improved therapeutic index over the naturally occurring VDR ligand 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in an in vivo preclinical surrogate model of psoriasis.
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MESH Headings
- Acetates/chemical synthesis
- Acetates/metabolism
- Acetates/pharmacology
- Animals
- Arylsulfonates/chemical synthesis
- Arylsulfonates/metabolism
- Arylsulfonates/pharmacology
- Caco-2 Cells
- Calcitriol/metabolism
- Calcitriol/pharmacology
- Cell Proliferation
- Cells, Cultured
- Colonic Neoplasms/metabolism
- Dose-Response Relationship, Drug
- Drug Evaluation, Preclinical
- Female
- Humans
- Hypercalcemia/metabolism
- Intestines
- Keratinocytes/drug effects
- Keratinocytes/metabolism
- Ligands
- Mice
- Mice, Hairless
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Models, Biological
- Osteoblasts/drug effects
- Osteoblasts/metabolism
- Psoriasis/drug therapy
- Rats
- Receptors, Calcitriol/agonists
- Receptors, Calcitriol/metabolism
- Signal Transduction
- Species Specificity
- Thiophenes/chemical synthesis
- Thiophenes/metabolism
- Thiophenes/pharmacology
- Transcription, Genetic
- Tumor Cells, Cultured
- Vitamin D/analogs & derivatives
- Vitamin D/chemical synthesis
- Vitamin D/metabolism
- Vitamin D/pharmacology
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Affiliation(s)
- Yanfei Ma
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Berket Khalifa
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Ying K. Yee
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Jianfen Lu
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Ai Memezawa
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Rajesh S. Savkur
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yoko Yamamoto
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Subba R. Chintalacharuvu
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Kazuyoshi Yamaoka
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Keith R. Stayrook
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Kelli S. Bramlett
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Qing Q. Zeng
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Srinivasan Chandrasekhar
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Xiao-Peng Yu
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Jared H. Linebarger
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Stephen J. Iturria
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Thomas P. Burris
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Shigeaki Kato
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - William W. Chin
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Sunil Nagpal
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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22
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Mazzini MJ, Schulze PC. Proatherogenic pathways leading to vascular calcification. Eur J Radiol 2006; 57:384-9. [PMID: 16458467 DOI: 10.1016/j.ejrad.2005.12.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 12/12/2005] [Accepted: 12/15/2005] [Indexed: 12/22/2022]
Abstract
Cardiovascular disease is the leading cause of morbidity and mortality in the western world and atherosclerosis is the major common underlying disease. The pathogenesis of atherosclerosis involves local vascular injury, inflammation and oxidative stress as well as vascular calcification. Vascular calcification has long been regarded as a degenerative process leading to mineral deposition in the vascular wall characteristic for late stages of atherosclerosis. However, recent studies identified vascular calcification in early stages of atherosclerosis and its occurrence has been linked to clinical events in patients with cardiovascular disease. Its degree correlates with local vascular inflammation and with the overall impact and the progression of atherosclerosis. Over the last decade, diverse and highly regulated molecular signaling cascades controlling vascular calcification have been described. Local and circulating molecules such as osteopontin, osteoprogerin, leptin and matrix Gla protein were identified as critical regulators of vascular calcification. We here review the current knowledge on molecular pathways of vascular calcification and their relevance for the progression of cardiovascular disease.
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Affiliation(s)
- Michael J Mazzini
- Department of Cardiology, Boston University Medical Center, Boston, MA 02118-2526, USA
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23
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Scsucova S, Palacios D, Savignac M, Mellström B, Naranjo JR, Aranda A. The repressor DREAM acts as a transcriptional activator on Vitamin D and retinoic acid response elements. Nucleic Acids Res 2005; 33:2269-79. [PMID: 15849313 PMCID: PMC1084319 DOI: 10.1093/nar/gki503] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Revised: 03/22/2005] [Accepted: 03/22/2005] [Indexed: 12/22/2022] Open
Abstract
DREAM (downstream regulatory element antagonist modulator) is a transcriptional repressor, which binds DREs (downstream response elements) in a Ca2+-regulated manner. The DREs consist of core GTCA motifs, very similar to binding motifs for non-steroid nuclear receptors. In this work, we find that DREAM stimulates basal and ligand-dependent activation of promoters containing vitamin D and retinoic acid response elements (VDREs and RAREs), consisting of direct repeats of the sequence AGT/GTCA spaced by 3 or 5 nt, respectively. Stimulation occurs when the element is located upstream, but not downstream, the transcription initiation site. Activation requires both Ca2+ binding to the EF-hands and the leucine-charged domains (LCDs), analogous to those responsible for the interaction of the nuclear receptors with coregulators. Further more, DREAM can bind both 'in vitro' and in chromatin immunoprecipitation assays to these elements. Importantly, 'in vivo' binding is only observed in vitamin D- or RA-treated cells. These results show that DREAM can function as an activator of transcription on certain promoters and demonstrate a novel role for DREAM acting as a potential modulator of genes containing binding sites for nuclear receptors.
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Affiliation(s)
- Sona Scsucova
- Instituto de Investigaciones Biomédicas ‘Alberto Sols’, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
| | - Daniela Palacios
- Instituto de Investigaciones Biomédicas ‘Alberto Sols’, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
| | - Magali Savignac
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
| | - Britt Mellström
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
| | - Jose Ramon Naranjo
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridArturo Duperier 4, 28029 Madrid, Spain
| | - Ana Aranda
- To whom correspondence should be addressed. Tel: +34 91 5854453; Fax: +34 91 5854401;
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24
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Abstract
Nuclear receptors modulate transcription through ligand-mediated recruitment of transcriptional coregulator proteins. The structural connection between ligand and coregulator is mediated by a molecular switch, made up of the most carboxy-terminal helix in the ligand-binding domain, helix 12. The dynamics of this switch are thought to underlie ligand specificity of nuclear receptor signaling, but the details of this control mechanism have remained elusive. This review highlights recent structural work on how the ligand controls this molecular switch and the modulation of this signaling pathway by receptor subtype and dimer partner.
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Affiliation(s)
- Kendall W Nettles
- The University of Chicago, The Ben May Institute for Cancer Research, Chicago, Illinois 60637, USA.
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25
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Abstract
The Vitamin D receptor (VDR) is a ligand-responsive transcription factor that forms homo- or heterodimers on response elements composed of two hexameric half-sites separated by three base pairs of spacer DNA. Binding of 1alpha,25-dihydroxyvitamin D(3) to the full-length VDR causes destabilization of the VDR homodimer and formation of a heterodimeric complex with the 9-cis retinoic acid receptor (RXR). VDR and RXR DNA-binding domains (DBDs) do not mimic this behavior, however: VDR DBD homodimers are formed exclusively, even in the presence of excess RXR DBD. Exploiting the asymmetry of the heterodimer and our knowledge of the homodimeric DBD interface, we have engineered VDR mutants that disfavor the homodimeric complex and allow for the formation of heterodimeric DBD complexes with RXR on DR3 elements. One of these complexes has been crystallized and its structure determined. However, the polarity of the proteins relative to the DNA is non-physiological due to crystal packing between symmetry-related VDR DBD protomers. This reveals a flattened energy landscape that appears to rely on elements outside of the core DBD for response element discrimination in the heterodimer.
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Affiliation(s)
- Paul L Shaffer
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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26
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Bettoun DJ, Burris TP, Houck KA, Buck DW, Stayrook KR, Khalifa B, Lu J, Chin WW, Nagpal S. Retinoid X receptor is a nonsilent major contributor to vitamin D receptor-mediated transcriptional activation. Mol Endocrinol 2003; 17:2320-8. [PMID: 12893883 DOI: 10.1210/me.2003-0148] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The vitamin D receptor (VDR) belongs to the thyroid hormone/retinoid receptor subfamily of nuclear receptors and functions as a heterodimer with retinoid X receptor (RXR). The RXR-VDR heterodimer, in contrast to other members of the class II nuclear receptor subfamily, is nonpermissive where RXR does not bind its cognate ligand, and therefore its role in VDR-mediated transactivation by liganded RXR-VDR has not been fully characterized. Here, we show a unique facet of the intermolecular RXR-VDR interaction, in which RXR actively participates in vitamin D3-dependent gene transcription. Using helix 3 and helix 12 mutants of VDR and RXR, we provide functional evidence that liganded VDR allosterically modifies RXR from an apo (unliganded)- to a holo (liganded)-receptor conformation, in the absence of RXR ligand. As a result of the proposed allosteric modification of RXR by liganded VDR, the heterodimerized RXR shows the "phantom ligand effect" and thus acquires the capability to recruit coactivators steroid receptor coactivator 1, transcriptional intermediary factor 2, and amplified in breast cancer-1. Finally, using a biochemical approach with purified proteins, we show that RXR augments the 1,25-dihydroxyvitamin D3-dependent recruitment of transcriptional intermediary factor 2 in the context of RXR-VDR heterodimer. These results confirm and extend the previous observations suggesting that RXR is a significant contributor to VDR-mediated gene expression and provide a mechanism by which RXR acts as a major contributor to vitamin D3-dependent transcription.
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Affiliation(s)
- David J Bettoun
- Gene Regulation, Bone and Inflammation Research, Eli Lilly & Company, Indianapolis, Indiana 46285, USA
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27
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Pike JW, Pathrose P, Barmina O, Chang CY, McDonnell DP, Yamamoto H, Shevde NK. Synthetic LXXLL peptide antagonize 1,25-dihydroxyvitamin D3-dependent transcription. J Cell Biochem 2003; 88:252-8. [PMID: 12520523 DOI: 10.1002/jcb.10336] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vitamin D receptor (VDR) is known to mediate the biological actions of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) through its ability to regulate cellular programs of gene expression. We identified VDR- and retinoid X receptor (RXR)-interacting LXXLL peptides using a mammalian two-hybrid system and examined whether these molecules could block vitamin D and 9-cis retinoic acid (9-cis RA) response. Peptides were identified that were reactive to RXR alone as well as to both VDR and RXR. Peptide fusion proteins were then examined in MC3T3 E1 cells for their ability to block induction of the osteocalcin promoter by 1,25(OH)(2)D(3) or stimulation of an RARE-TK reporter by 9-cis RA. Peptides that interacted with both VDR and RXR blocked 1,25(OH)(2)D(3)-dependent transcription by up to 75%. Peptides that interacted with RXR blocked 9-cis RA induced transcription. Two RXR-interacting peptides, however, were also found to block 1,25(OH)(2)D(3) response effectively. These studies support the idea that comodulator recruitment is essential for VDR- and RXR-mediated gene expression and that RXR is required for 1,25(OH)(2)D(3)-induced osteocalcin gene transcription. This approach may represent a novel means of assessing the contribution of RXR in various endogenous biological responses to 1,25(OH)(2)D(3).
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Affiliation(s)
- J Wesley Pike
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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28
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Pathrose P, Barmina O, Chang CY, McDonnell DP, Shevde NK, Pike JW. Inhibition of 1,25-dihydroxyvitamin D3-dependent transcription by synthetic LXXLL peptide antagonists that target the activation domains of the vitamin D and retinoid X receptors. J Bone Miner Res 2002; 17:2196-205. [PMID: 12469913 DOI: 10.1359/jbmr.2002.17.12.2196] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The vitamin D receptor (VDR) is known to mediate the biological actions of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] through its ability to regulate cellular programs of gene expression. Although RXR appears to participate as a heterodimeric partner with the VDR, absolute evidence for its role remains equivocal in vivo. To test this role and to investigate the requirement for comodulator interaction, we identified VDR- and retinoid X receptor (RXR)-interacting LXXLL peptides and examined whether these molecules could block vitamin D and 9-cis retinoic acid (9-cis RA) response. We used a mammalian cell two-hybrid system to screen a series of nuclear receptor (NR)-reactive LXXLL peptides previously identified through phage display screening for hormone-dependent reactivity with either VDR or RXR. Three categories of peptides were identified: those reactive with both VDR and RXR, those selective for RXR, and those unreactive to either receptor. Peptide fusion proteins were then examined in MC3T3-E1 cells for their ability to block induction of the osteocalcin (OC) promoter by 1,25(OH)2D3 or stimulation of a retinoic acid response element-thymidine kinase (RARE-TK) reporter by 9-cis-RA. Peptides that interacted with both VDR and RXR blocked 1,25(OH)2D3-dependent transcription by up to 75%. Control LXXLL sequences derived from Src-1 and Grip also suppressed 1,25(OH)2D3-induced transactivation; peptides that interacted with RXR blocked 9-cis-RA-induced transcription. Interestingly, two RXR-interacting peptides were also found to block 1,25(OH)2D3 response effectively. These studies support the idea that comodulator recruitment is essential for VDR- and RXR-mediated gene expression and that RXR is required for 1,25(OH)2D3-induced OC gene transcription. This approach may represent a novel means of assessing the contribution of RXR in various endogenous biological responses to 1,25(OH)2D3.
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Affiliation(s)
- Peterson Pathrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
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29
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van den Bemd GJCM, Jhamai M, Staal A, van Wijnen AJ, Lian JB, Stein GS, Pols HAP, van Leeuwen JPTM. A central dinucleotide within vitamin D response elements modulates DNA binding and transactivation by the vitamin D receptor in cellular response to natural and synthetic ligands. J Biol Chem 2002; 277:14539-46. [PMID: 11834737 DOI: 10.1074/jbc.m111224200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is considerable divergence in the sequences of steroid receptor response elements, including the vitamin D response elements (VDREs). Two major VDRE-containing and thus 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3))-regulated genes are the two non-collagenous, osteoblast-derived bone matrix proteins osteocalcin and osteopontin. We observed a stronger induction of osteopontin than osteocalcin mRNA expression by 1,25-(OH)(2)D(3). Subsequently, we have shown that vitamin D receptor/retinoid X receptor alpha (VDR/RXRalpha) heterodimers bind more tightly to the osteopontin VDRE than to the osteocalcin VDRE. Studies using point mutants revealed that the internal dinucleotide at positions 3 and 4 of the proximal steroid half-element are most important for modulating the strength of receptor binding. In addition, studies with VDRE-driven luciferase reporter gene constructs revealed that the central dinucleotide influences the transactivation potential of VDR/RXRalpha with the same order of magnitude as that observed in the DNA binding studies. The synthetic vitamin D analog KH1060 is a more potent stimulator of transcription and inducer of VDRE binding of VDR/RXR in the presence of nuclear factors isolated from ROS 17/2.8 osteoblast-like cells than the natural ligand 1,25-(OH)(2)D(3). Interestingly, however, KH1060 is comparable or even less potent than 1,25-(OH)(2)D(3) in stimulating VDRE binding of in vitro synthesized VDR/RXRalpha. Thus, the extent of 1,25-(OH)(2)D(3)- and KH1060-dependent binding of VDR/RXRalpha is specified by a central dinucleotide in the VDRE, and the ligand-induced effects on DNA binding are in part controlled by the cellular context of nuclear proteins.
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30
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Staeva-Vieira TP, Freedman LP. 1,25-dihydroxyvitamin D3 inhibits IFN-gamma and IL-4 levels during in vitro polarization of primary murine CD4+ T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:1181-9. [PMID: 11801653 DOI: 10.4049/jimmunol.168.3.1181] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Following their activation, naive CD4+ T cells can differentiate into one of two effector cell subsets, Th1 and Th2. These two subsets have different cytokine secretion patterns and thus mediate separate arms of the immune response. It has been established that the fat-soluble vitamin D(3) metabolite 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) and its nuclear receptor, the vitamin D receptor, play an important role in the immune system primarily through the transcriptional inhibition of cytokine genes that either are required for Th1 differentiation or are products of differentiated Th1 cells. Therefore, we wanted to test directly the ability of 1,25(OH)(2)D(3) to alter the Th differentiation process. Our results indicate that 1,25(OH)(2)D(3) inhibits not only the Th1 cytokine IFN-gamma but also the Th2 cytokine IL-4 in naive CD62 ligand+CD4+ T cells during their in vitro polarization. This effect is most dramatic when the ligand is present from the onset of the differentiation process. If the ligand is added after the polarization has ensued, the inhibition is significantly diminished. In activated (CD62 ligand-CD4+) T cells, 1,25(OH)(2)D(3) is still able to inhibit IFN-gamma but has no effect on IL-4 production. Our results also indicate that inhibition of these two cytokines in naive cells by vitamin D receptor and its ligand is neither a result of a cell cycle block nor an inhibition of Th1 or Th2 transcription factor expression but, rather, at least in the case of Th2 differentiation, an attenuation of IL-4 transcription by the receptor.
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Affiliation(s)
- Teodora P Staeva-Vieira
- Immunology and Cell Biology Programs, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA
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31
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Ohashi E, Inoue K, Kagechika H, Hong SH, Takahashi T, Mochizuki M, Nishimura R, Sasaki N. Effect of natural and synthetic retinoids on the proliferation and differentiation of three canine melanoma cell lines. J Vet Med Sci 2002; 64:169-72. [PMID: 11913557 DOI: 10.1292/jvms.64.169] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of two natural retinoids and synthetic retinoids with or without retinoid synergists on the proliferation and differentiation of 3 melanoma cell lines were investigated in vitro. No retinoids showed significant growth inhibitory effect on these cell lines when used alone, however, cell differentiation and significant growth inhibition were observed when treated with a combination of retinoids and a retinoid synergist. This study may suggest that, though the cells showed low susceptibilities when retinoids were treated alone, the combination of retinoids and a retinoid synergist may be effective to control the growth of canine melanoma cell lines.
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Affiliation(s)
- Emi Ohashi
- Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan
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32
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Ward JO, McConnell MJ, Carlile GW, Pandolfi PP, Licht JD, Freedman LP. The acute promyelocytic leukemia-associated protein, promyelocytic leukemia zinc finger, regulates 1,25-dihydroxyvitamin D(3)-induced monocytic differentiation of U937 cells through a physical interaction with vitamin D(3) receptor. Blood 2001; 98:3290-300. [PMID: 11719366 DOI: 10.1182/blood.v98.12.3290] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocyte differentiation induced by 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is interrupted during the course of acute promyelocytic leukemia (APL). One form of APL is associated with the translocation t(11;17), which joins the promyelocytic leukemia zinc finger (PLZF) and retinoic acid receptor alpha (RARalpha) genes. Because PLZF is coexpressed in the myeloid lineage with the vitamin D(3) receptor (VDR), the interplay between PLZF and VDR was examined. It was found that PLZF interacts directly with VDR. This occurred at least partly through contacts in the DNA-binding domain of VDR and the broad complex, tram-trak, bric-a-brac/pox virus zinc finger (BTB/POZ) domain of PLZF. Moreover, PLZF altered the mobility of VDR derived from nuclear extracts when bound to its cognate binding site, forming a slowly migrating DNA-protein complex. Overexpression of PLZF in a monocytic cell line abrogated 1,25(OH)(2)D(3) activation from both a minimal VDR responsive reporter and the promoter of p21(WAF1/CIP1), a target gene of VDR. Deletion of the BTB/POZ domain significantly relieved PLZF-mediated repression of 1,25(OH)(2)D(3)-dependent activation. In addition, stable, inducible expression of PLZF in U937 cells inhibited the ability of 1,25(OH)(2)D(3) to induce surface expression of the monocytic marker CD14 and morphologic changes associated with differentiation. These results suggest that PLZF may play an important role in regulating the process by which 1,25(OH)(2)D(3) induces monocytic differentiation in hematopoietic cells.
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Affiliation(s)
- J O Ward
- Programs of Cell Biology and Human Genetics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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33
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Jensen SS, Madsen MW, Lukas J, Binderup L, Bartek J. Inhibitory effects of 1alpha,25-dihydroxyvitamin D(3) on the G(1)-S phase-controlling machinery. Mol Endocrinol 2001; 15:1370-80. [PMID: 11463860 DOI: 10.1210/mend.15.8.0673] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The nuclear hormone 1alpha,25-dihydroxyvitamin D(3) induces cell cycle arrest, differentiation, or apoptosis depending on target cell type and state. Although the antiproliferative effect of 1alpha,25-dihydroxyvitamin D(3) has been known for years, the molecular basis of the cell cycle blockade by 1alpha,25-dihydroxyvitamin D(3) remains largely unknown. Here we have investigated the mechanisms underlying the G(1) arrest induced upon 1alpha,25-dihydroxyvitamin D(3) treatment of the human breast cancer cell line MCF-7. Twenty-four-hour exposure of exponentially growing MCF-7 cells to 1alpha,25-dihydroxyvitamin D(3) impeded proliferation by preventing S phase entry, an effect that correlated with appearance of the growth-suppressing, hypophosphorylated form of the retinoblastoma protein (pRb), and modulation of cyclin-dependent kinase (cdk) activities of cdk-4, -6, and -2. Time course immunochemical and biochemical analyses of the cellular and molecular effects of 1alpha,25-dihydroxyvitamin D(3) treatment for up to 6 d revealed a dynamic chain of events, preventing activation of cyclin D1/cdk4, and loss of cyclin D3, which collectively lead to repression of the E2F transcription factors and thus negatively affected cyclin A protein expression. While the observed 10-fold inhibition of cyclin D1/cdk 4-associated kinase activity appeared independent of cdk inhibitors, the activity of cdk 2 decreased about 20-fold, reflecting joint effects of the lower abundance of its cyclin partners and a significant increase of the cdk inhibitor p21(CIP1/WAF1), which blocked the remaining cyclin A(E)/cdk 2 complexes. Together with a rapid down-modulation of the c-Myc oncoprotein in response to 1alpha,25-dihydroxyvitamin D(3), these results demonstrate that 1alpha,25-dihydroxyvitamin D(3) inhibits cell proliferation by targeting several key regulators governing the G(1)/S transition.
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Affiliation(s)
- S S Jensen
- Institute of Cancer Biology, The Danish Cancer Society, DK-2100 Copenhagen, Denmark
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Abstract
The nuclear hormone receptor superfamily includes receptors for thyroid and steroid hormones, retinoids and vitamin D, as well as different "orphan" receptors of unknown ligand. Ligands for some of these receptors have been recently identified, showing that products of lipid metabolism such as fatty acids, prostaglandins, or cholesterol derivatives can regulate gene expression by binding to nuclear receptors. Nuclear receptors act as ligand-inducible transcription factors by directly interacting as monomers, homodimers, or heterodimers with the retinoid X receptor with DNA response elements of target genes, as well as by "cross-talking" to other signaling pathways. The effects of nuclear receptors on transcription are mediated through recruitment of coregulators. A subset of receptors binds corepressor factors and actively represses target gene expression in the absence of ligand. Corepressors are found within multicomponent complexes that contain histone deacetylase activity. Deacetylation leads to chromatin compactation and transcriptional repression. Upon ligand binding, the receptors undergo a conformational change that allows the recruitment of multiple coactivator complexes. Some of these proteins are chromatin remodeling factors or possess histone acetylase activity, whereas others may interact directly with the basic transcriptional machinery. Recruitment of coactivator complexes to the target promoter causes chromatin decompactation and transcriptional activation. The characterization of corepressor and coactivator complexes, in concert with the identification of the specific interaction motifs in the receptors, has demonstrated the existence of a general molecular mechanism by which different receptors elicit their transcriptional responses in target genes.
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Affiliation(s)
- A Aranda
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain.
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Wang Q, Lee D, Sysounthone V, Christakos S, Korah R, Wieder R. 1,25-dihydroxyvitamin D3 and retonic acid analogues induce differentiation in breast cancer cells with function- and cell-specific additive effects. Breast Cancer Res Treat 2001; 67:157-68. [PMID: 11519864 DOI: 10.1023/a:1010643323268] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vitamin D3 derivatives and retinoids can induce cell cycle arrest, differentiation and cell death in many cell lines. These compounds can act cooperatively in some of their functions and may be of potential use either individually or in combination in the treatment of breast cancer. The effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), all-trans retinoic acid (ATRA) and several analogues were evaluated on malignant phenotypic traits of breast cancer cell lines MCF-7, T-47D and MDA-MB-231. Both 1,25(OH)2D3 and ATRA caused a decrease in anchorage independent colony formation in MCF-7 and T-47D cells in a dose-dependent manner. The effects of 1,25(OH)2D3 10(-10) and 10(-9) M were synergistic with ATRA 10(-8) M in T-47D cells but were antagonistic in both MCF-7 and in T-47D cells at most concentrations. Both 1,25(OH)2D3 and ATRA individually induced an accumulation of MCF-7 cells in the G1 phase of the cell cycle and an associated increase in p21WAFI/CiP1, p27KiP1 and a dephosphorylation of Rb but the effects were not additive. Both compounds inhibited the invasive capacity of MDA-MB-231 cells. 1,25(OH)2D3 but not ATRA caused an increase in E-cadherin levels in MDA-MB-231 cells. These two functions were not additive. The compounds 1,25(OH)2D3, a noncalcemic analogue 1,25(OH)2-16-ene-23-yne-D3, ATRA, AGN195183, an RARalpha-specific agonist, and AGN190168 (tazarotene), an RARbeta/gamma-selective agonist, induced differentiation as determined by measurements of lipid droplet formation. The individual effects of 1,25(OH)2-16-ene-23-yne-D3 combined with ATRA or with tazarotene at 10(-9) M each were additive in MCF-7 and MDA-MB-231 cells on lipid formation. The data demonstrate that both 1,25(OH)2D3, ATRA, and selected analogues induce a more differentiated phenotype in breast cancer cells with additive effects that are function- and cell-specific.
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Affiliation(s)
- Q Wang
- Department of Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark 07103, USA
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Koszewski NJ, Kiessling S, Malluche HH. Isolation of genomic DNA sequences that bind vitamin D receptor complexes. Biochem Biophys Res Commun 2001; 283:188-94. [PMID: 11322787 DOI: 10.1006/bbrc.2001.4734] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vitamin D signaling is believed to be transduced by a heterodimeric receptor complex that binds to specific sequences of DNA termed vitamin D response elements (VDREs) in the promoter regions of target genes. However, recent studies have suggested that considerable flexibility exists in the types of binding sites the vitamin D receptor (VDR) is capable of recognizing, including some that bind VDR homodimers. In this report, a screening method involving immunoselection and PCR amplification was utilized to examine genomic binding sites for the receptor. Four individual fragments ranging in size from ca. 250-320 bp were nominally isolated from the amplified pool of captured fragments for further analysis. Each of the four sequences was capable of forming specific, unique VDR complexes using recombinant human VDR (rhVDR) alone or rhVDR heteromers formed in conjunction with the addition of recombinant human retinoid X receptor alpha (rhRXRalpha). Two of these fragments exhibited significant hormone-dependent repression of luciferase activity when linked to a thymidine kinase driven reporter vector. DNaseI footprinting revealed specific binding over DR+3 or related half-site sequences found within both of these DNA fragments. The results from this study demonstrate that specific, functional binding sites for the VDR can be successfully isolated from genomic DNA and should aid in the discovery of genes regulated by the steroid hormone.
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Affiliation(s)
- N J Koszewski
- Division of Nephrology, Bone and Mineral Metabolism, University of Kentucky Medical Center, Lexington 40536-0298, USA.
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Prüfer K, Racz A, Lin GC, Barsony J. Dimerization with retinoid X receptors promotes nuclear localization and subnuclear targeting of vitamin D receptors. J Biol Chem 2000; 275:41114-23. [PMID: 11001945 DOI: 10.1074/jbc.m003791200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The vitamin D receptor (VDR) acts as heterodimer with the retinoid X receptor alpha (RXR) to control transcriptional activity of target genes. To explore the influence of heterodimerization on the subcellular distribution of these receptors in living cells, we developed a series of fluorescent-protein chimeras. The steady-state distribution of the yellow fluorescent protein-RXR was more nuclear than the unliganded green fluorescent protein (GFP)-VDR. Coexpression of RXR-blue fluorescent protein (BFP) promoted nuclear accumulation of GFP-VDR by influencing both nuclear import and retention. Fluorescence resonance energy transfer microscopy (FRET) demonstrated that the unliganded GFP-VDR and RXR-BFP form heterodimers. The increase in nuclear heterodimer content correlated with an increase in basal transcriptional activity. FRET also revealed that calcitriol induces formation of multiple nuclear foci of heterodimers. Mutational analysis showed a correlation between hormone-dependent nuclear VDR foci formation and DNA binding. RXR-BFP also promoted hormone-dependent nuclear accumulation and intranuclear foci formation of a nuclear localization signal mutant receptor (nlsGFP-VDR) and rescued its transcriptional activity. Heterodimerization mutant RXR failed to alter GFP-VDR and nlsGFP-VDR distribution or activity. These experiments suggest that RXR has a profound effect on VDR distribution. This effect of RXR to promote nuclear accumulation and intranuclear targeting contributes to the regulation of VDR activity and probably the activity of other heterodimerization partners.
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Affiliation(s)
- K Prüfer
- Laboratory of Cell Biochemistry and Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
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Goyette P, Feng Chen C, Wang W, Seguin F, Lohnes D. Characterization of retinoic acid receptor-deficient keratinocytes. J Biol Chem 2000; 275:16497-505. [PMID: 10748128 DOI: 10.1074/jbc.m909382199] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinoids are essential for normal epidermal growth and differentiation and show potential for the prevention or treatment of various epithelial neoplasms. The retinoic acid receptors (RARalpha, -beta, and -gamma) are transducers of the retinoid signal. The epidermis expresses RARgamma and RARalpha, both of which are potential mediators of the effects of retinoids in the epidermis. To further investigate the role(s) of these receptors, we derived transformed keratinocyte lines from wild-type, RARalpha, RARgamma, and RARalphagamma null mice and investigated their response to retinoids, including growth inhibition, markers of growth and differentiation, and AP-1 activity. Our results indicate that RARgamma is the principle receptor contributing to all-trans-retinoic acid (RA)-mediated growth arrest in this system. This effect partially correlated with inhibition of AP-1 activity. In the absence of RARs, the synthetic retinoid N-(4-hydroxyphenyl)-retinamide inhibited growth; this was not observed with RA, 9-cis RA, or the synthetic retinoid (E)-4-[2-(5, 5, 8, 8 tetramethyl-5,6,7,8-tetrahydro-2-naphthalenyl)-1-propenyl] benzoic acid. Finally, both RARalpha and RARgamma differently affected the expression of some genes, suggesting both specific and overlapping roles for the RARs in keratinocytes.
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Affiliation(s)
- P Goyette
- Department of Molecular Biology, Université de Montréal, Division of Experimental Medicine, McGill University, and the Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins, Ouest, Montréal, Québec H2W 1R7, Canada
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Fritsche J, Stonehouse TJ, Katz DR, Andreesen R, Kreutz M. Expression of retinoid receptors during human monocyte differentiation in vitro. Biochem Biophys Res Commun 2000; 270:17-22. [PMID: 10733898 DOI: 10.1006/bbrc.2000.2371] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
1alpha,25-dihydroxyvitamin D(3) (1,25(OH)(2)VD(3)) and retinoic acid (RA) modulate the activation of monocytes (MO) and their differentiation into macrophages (MAC). As these effects are mostly mediated by heterodimers or homodimers of the specific nuclear receptors for 1,25(OH)(2)VD(3) and RA, we investigated the expression of the retinoic acid receptors (RAR) alpha, beta, and gamma and the retinoid X-receptor (RXR) alpha in MO during differentiation into MAC or dendritic cells (DC). The mRNA of all investigated receptors except RARbeta was detected in short-term cultured MO. During differentiation of MO to MAC the mRNA expression of the RA receptors decreased. In contrast, along the differentiation pathway of MO to DC, only the mRNA expression of RARgamma declined, whereas RARalpha and RXRalpha were constantly expressed at a high level. Despite the strong expression of RARalpha and RXRalpha at mRNA level in MO-derived DC, the protein expression of the receptors was low in these cells. However, MO and MO-derived MAC showed a strong expression of these receptors at protein level. This suggests that a posttranscriptional or posttranslational mechanism of receptor regulation is occurring in these cells, and in particular in the DC. The inverse regulation of RA receptor expression and protein levels between MAC and DC may control the responsiveness of these cells to 1,25(OH)(2)VD(3) and RA.
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Affiliation(s)
- J Fritsche
- Department of Hematology and Oncology, University of Regensburg, Franz-Josef-Strauss-Allee 11, Regensburg, D-93042, Germany
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Miyabayashi T, Palfreyman MT, Sluder AE, Slack F, Sengupta P. Expression and function of members of a divergent nuclear receptor family in Caenorhabditis elegans. Dev Biol 1999; 215:314-31. [PMID: 10545240 DOI: 10.1006/dbio.1999.9470] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear receptors (NRs) are a large class of ligand-regulated transcriptional modulators that have been shown to play roles in many developmental processes. The Caenorhabditis elegans genome is predicted to encode a large and divergent family of NR proteins. The functions of most of these genes are unknown. As a first step toward defining their roles, we have initiated an expression and functional survey of a subset of these genes. In this study, we demonstrate expression of 21 of 28 NR genes examined, indicating that a large fraction of the predicted genes likely encode functional gene products. We show that five genes are expressed predominantly in neuronal cells, while others are expressed in multiple cell types. Interestingly, we find that eight genes are expressed exclusively in the lateral hypodermal (seam) cells. These eight genes share a high degree of overall homology and cluster in a neighbor-joining tree derived from sequence analysis of the NRs, suggesting that they arose by gene duplication from a common ancestor. We show that overexpression of each of three members of this subfamily results in similar developmental defects, consistent with a redundant role for these genes in the function of the lateral hypodermal cells.
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Affiliation(s)
- T Miyabayashi
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, USA
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Towers TL, Staeva TP, Freedman LP. A two-hit mechanism for vitamin D3-mediated transcriptional repression of the granulocyte-macrophage colony-stimulating factor gene: vitamin D receptor competes for DNA binding with NFAT1 and stabilizes c-Jun. Mol Cell Biol 1999; 19:4191-9. [PMID: 10330159 PMCID: PMC104378 DOI: 10.1128/mcb.19.6.4191] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously described a control element in the granulocyte-macrophage colony-stimulating factor (GM-CSF) enhancer that is necessary and sufficient to mediate both transcriptional activation in response to T-cell stimuli and transcriptional repression by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] through the vitamin D3 receptor (VDR). This DNA element is a composite site that is recognized by both Fos-Jun and NFAT1; it is directly bound by VDR in the absence of a retinoid X receptor as an apparent monomer, and it is bound in a unique tertiary conformation. We describe here the mechanism by which VDR elicits its transcriptional inhibitory effect. Firstly, VDR outcompetes NFAT1 for binding to the composite site. Overexpression of NFAT1 in vivo by transient transfection is able to relieve the 1,25(OH)2D3-dependent repression. Secondly, VDR stabilizes the binding of a Jun-Fos heterodimer to the adjacent AP-1 portion of the element. This appears to occur through a direct interaction between VDR and c-Jun, as demonstrated in vitro by direct glutathione S-transferase coprecipitation assays. In vivo, overexpression of c-Jun, but not c-Fos, leads to a rescue of the 1, 25(OH)2D3-mediated repression. Transfected FLAG-VDR bound to the NFAT1-AP-1 DNA binding element can be selectively precipitated from nuclear extracts that are made from cells treated with activating agents in the presence of 1,25(OH)2D3. VDR is not detected in the complex in the absence of the ligand. Thus, VDR acts selectively on the two components required for activation of this promoter/enhancer: it competes with NFAT1 for binding to the composite site, positioning itself adjacent to Jun-Fos on the DNA. Co-occupancy apparently leads to an inhibitory effect on c-Jun's transactivation function. These two events mediated by VDR effectively block the NFAT1-AP-1 activation complex, resulting in an attenuation of activated GM-CSF transcription.
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Affiliation(s)
- T L Towers
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Cornell University Graduate School of Medical Sciences, New York, New York 10021, USA
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Jiménez-Lara AM, Aranda A. Vitamin D represses retinoic acid-dependent transactivation of the retinoic acid receptor-beta2 promoter: the AF-2 domain of the vitamin D receptor is required for transrepression. Endocrinology 1999; 140:2898-907. [PMID: 10342883 DOI: 10.1210/endo.140.6.6770] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Retinoic acid (RA)-dependent activation of the RA receptor beta2 (RARbeta2) gene in embryonal carcinoma cells is mediated by binding of retinoid receptor heterodimers (RAR/RXR) to a RA response element (RARE) located closely to the TATA box. We have analyzed the effect of vitamin D on the response of the RARbeta2 promoter to RA in pituitary GH4C1 cells that coexpress receptors for retinoids and vitamin D. Incubation with vitamin D markedly reduced the response to RA caused by transcriptional interference of the vitamin D receptor (VDR) on the RARE. This DNA element binds VDR/RXR heterodimers with high affinity, and these inactive heterodimers can displace active RAR/RXR from the RARE. Overexpression of RXR in GH4C1 cells, as well as incubation with BMS649 (a RXR-specific ligand), increased the inhibitory effect of vitamin D, suggesting that the VDR/RXR heterodimer is the repressive species and that titration of RXR is not responsible for this inhibition. Although DNA binding could be required for full potency of the inhibitory activity of VDR, it is not absolutely required because a truncated receptor (VDR delta1-111), lacking the DNA binding domain, also displays repressor activity. Furthermore, the ability to mediate transrepression by vitamin D was strongly decreased when a mutant VDR in which the last 12 C-terminal aminoacids have been deleted (VDR deltaAF-2) was used. Because this region contains the domain responsible for ligand-dependent recruitment of coactivators, titration of common coactivators for VDR and RAR could be involved in the inhibitory effect of vitamin D. In agreement with this hypothesis, overexpression of E1A, which can act as a RARbeta2 promoter-specific coactivator, significantly reversed repression by vitamin D.
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Affiliation(s)
- A M Jiménez-Lara
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Spain
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Jimenez-Lara AM, Aranda A. The vitamin D receptor binds in a transcriptionally inactive form and without a defined polarity on a retinoic acid response element. FASEB J 1999; 13:1073-81. [PMID: 10336890 DOI: 10.1096/fasebj.13.9.1073] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Heterodimers of the vitamin D receptor (VDR) with the retinoid X receptor (RXR) bind in a transcriptionally unproductive manner to the retinoic acid response element present in the retinoic acid receptor-beta2 promoter. This element is composed of a direct repeat (DR) of the sequence PuGTTCA spaced by five nucleotides. However, the same sequence separated by three nucleotides (DR3) acts as a strong vitamin D response element. Here we show that the polarity of binding of the heterodimers to the DR3 was 5'-RXR-VDR-3', whereas on the DR5, both heterodimeric partners bind indistinctly to the 5' or 3' hemi-sites. These results suggest that the response elements can allosterically regulate the conformation of the receptors to determine positive or negative regulation of gene expression. Despite the altered polarity, the DR5-bound heterodimer was able to recruit the nuclear receptor coactivator ACTR in a vitamin D-dependent fashion. Furthermore, binding of the corepressor SMRT (silencing mediator of retinoid and thyroid hormone receptors) to the RXR/VDR heterodimer on a DR5 was not observed. Binding of RXR/VDR heterodimers to DRs with different transcriptional outcomes may generate selectivity and provide a greater complexity and flexibility to the vitamin D responses.
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Affiliation(s)
- A M Jimenez-Lara
- Instituto de Investigaciones Biomédicas. CSIC-UAM, Madrid, Spain
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Malloy PJ, Pike JW, Feldman D. The vitamin D receptor and the syndrome of hereditary 1,25-dihydroxyvitamin D-resistant rickets. Endocr Rev 1999; 20:156-88. [PMID: 10204116 DOI: 10.1210/edrv.20.2.0359] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Makishima M, Shudo K, Honma Y. Greater synergism of retinoic acid receptor (RAR) agonists with vitamin D3 than that of retinoid X receptor (RXR) agonists with regard to growth inhibition and differentiation induction in monoblastic leukemia cells. Biochem Pharmacol 1999; 57:521-9. [PMID: 9952315 DOI: 10.1016/s0006-2952(98)00329-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Retinoids and 1alpha,25-dihydroxyvitamin D3 (VD3) cooperatively induce the differentiation of myeloid leukemia cells. We investigated the role of retinoid receptors (RARs and RXRs) in the combined effects of retinoids and VD3 on growth inhibition and differentiation induction in human monoblastic leukemia U937 cells by using RAR- or RXR-selective retinoids. An isobologram analysis showed that both combinations were synergistic with regard to inhibiting the proliferation, and RAR agonists exhibited greater synergism with VD3 than did RXR agonists. RXR agonists alone induced nitroblue tetrazolium (NBT) reduction and expression of CD11b in U937 cells, whereas RAR agonists alone did not. On the other hand, RAR agonists and RXR agonists enhanced the differentiation induced by VD3, but RXR agonists required higher concentrations. An RAR antagonist inhibited the differentiation induced by RAR agonists plus VD3, but not that induced by RXR agonists plus VD3. Thus, RARs and RXRs act differently in their synergism with VD3. RAR agonists are more potent than RXR agonists with regard to synergism with VD3, and their combination may be useful in differentiation therapy against myeloid leukemia.
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Affiliation(s)
- M Makishima
- Department of Chemotherapy, Saitama Cancer Center Research Institute, Japan
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Freedman LP. Transcriptional targets of the vitamin D3 receptor-mediating cell cycle arrest and differentiation. J Nutr 1999; 129:581S-586S. [PMID: 10064337 DOI: 10.1093/jn/129.2.581s] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We are exploring the mechanism of action of the hormonal form of the nutrient vitamin D, 1,25(OH)2D3, and its cognate nuclear receptor at the level of gene control. In doing so, we have focused on a dual track as follows: 1) to define the vitamin D3 receptor (VDR) function and structure by examining its various actions at the molecular level; and 2) to isolate and characterize VDR target genes that might be playing key roles in mediating vitamin D growth suppression and differentiation in responsive cells, specifically, the elucidation of vitamin D target genes as they relate to myeloid differentiation. Here, we will summarize some of our recent results from both tracks because a detailed understanding of how VDR functions as a ligand-regulated transcription factor will allow us to study its actions on these newly discovered genes more effectively.
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Affiliation(s)
- L P Freedman
- Memorial Sloan-Kettering Cancer Center and Sloan-Kettering Division, Graduate School of Medical Sciences, Cornell University, New York, NY 10021, USA
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Abstract
The important reactions that occur to the vitamin D molecule and the important reactions involved in the expression of the final active form of vitamin D are reviewed in a critical manner. After an overview of the metabolism of vitamin D to its active form and to its metabolic degradation products, the molecular understanding of the 1alpha-hydroxylation reaction and the 24-hydroxylation reaction of the vitamin D hormone is presented. Furthermore, the role of vitamin D in maintenance of serum calcium is reviewed at the physiological level and at the molecular level whenever possible. Of particular importance is the regulation of the parathyroid gland by the vitamin D hormone. A third section describes the known molecular events involved in the action of 1alpha,25-dihydroxyvitamin D3 on its target cells. This includes reviewing what is now known concerning the overall mechanism of transcriptional regulation by vitamin D. It describes the vitamin D receptors that have been cloned and identified and describes the coactivators and retinoid X receptors required for the function of vitamin D in its genomic actions. The presence of receptor in previously uncharted target organs of vitamin D action has led to a study of the possible function of vitamin D in these organs. A good example of a new function described for 1alpha,25-dihydroxyvitamin D3 is that found in the parathyroid gland. This is also true for the role of vitamin D hormone in skin, the immune system, a possible role in the pancreas, i.e., in the islet cells, and a possible role in female reproduction. This review also raises the intriguing question of whether vitamin D plays an important role in embryonic development, since vitamin D deficiency does not prohibit development, nor does vitamin D receptor knockout. The final section reviews some interesting analogs of the vitamin D hormone and their possible uses. The review ends with possible ideas with regard to future directions of vitamin D drug design.
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Affiliation(s)
- G Jones
- Department of Biochemistry, Queen's University, Kingston, Ontario, Canada
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Rachez C, Suldan Z, Ward J, Chang CP, Burakov D, Erdjument-Bromage H, Tempst P, Freedman LP. A novel protein complex that interacts with the vitamin D3 receptor in a ligand-dependent manner and enhances VDR transactivation in a cell-free system. Genes Dev 1998; 12:1787-800. [PMID: 9637681 PMCID: PMC316901 DOI: 10.1101/gad.12.12.1787] [Citation(s) in RCA: 314] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/1997] [Accepted: 04/17/1998] [Indexed: 11/25/2022]
Abstract
Nuclear receptors transduce hormonal signals by binding directly to DNA target sites in promoters and modulating the transcription of linked genes. Receptor-mediated transactivation appears to be potentiated in response to ligand by a number of coactivators that may provide key interactions with components of the transcription preinitiation complex and/or alter chromatin structure. Here, we use the vitamin D3 receptor ligand-binding domain (VDR LBD) as an affinity matrix to identify components of a transcriptionally active nuclear extract that interact with VDR in response to ligand. We describe the purification of a complex of at least 10 VDR interacting proteins (DRIPs) ranging from 65 to 250 kD that associate with the receptor in a strictly 1,25-dihydroxyvitamin D3-dependent manner. These proteins also appear to interact with other, but not all, nuclear receptors, such as the thyroid hormone receptor. The DRIPs are distinct from known nuclear receptor coactivators, although like these coactivators, their interaction also requires the AF-2 transactivation motif of VDR. In addition, the DRIP complex contains histone acetyltransferase activity, indicating that at least one or more of the DRIPs may function at the level of nucleosomal modification. However, we show that the DRIPs selectively enhance the transcriptional activity of VDR on a naked DNA template utilizing a cell-free, ligand-dependent transcription assay. Moreover, this activity can be specifically depleted from the extract by liganded, but not unliganded, VDR-LBD. Overexpression of DRIP100 in vivo resulted in a strong squelching of VDR transactivation, suggesting the sequestration of other limiting factors, including components of the DRIP complex. These results demonstrate the existence of a new complex of novel functional nuclear receptor coactivators.
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Affiliation(s)
- C Rachez
- Cell Biology Program,Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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Towers TL, Freedman LP. Granulocyte-macrophage colony-stimulating factor gene transcription is directly repressed by the vitamin D3 receptor. Implications for allosteric influences on nuclear receptor structure and function by a DNA element. J Biol Chem 1998; 273:10338-48. [PMID: 9553089 DOI: 10.1074/jbc.273.17.10338] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The primary function of activated T lymphocytes is to produce various cytokines necessary to elicit an immune response; these cytokines include interleukin-2 (IL-2), interleukin-4, and granulocyte-macrophage colony-stimulating factor (GMCSF). Steroid hormones and vitamin A and D3 metabolites act to repress the expression of cytokines. 1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) down-modulates activated IL-2 expression at the level transcription, through direct antagonism of the transactivating complex NFAT-1/AP-1 by the vitamin D3 receptor (VDR). We report here that GMCSF transcription in Jurkat T cells is also directly repressed by 1, 25-(OH)2D3 and VDR. Among four NFAT/AP-1 elements in the GMCSF enhancer, we have focused on one such element that when multimerized, is sufficient in mediating both activation by NFAT-1 and AP-1 and repression in response to 1,25-(OH)2D3. Although this element does not contain any recognizable vitamin D response elements (VDREs), high affinity DNA binding by recombinant VDR is observed. In contrast to VDR interactions with positive VDREs, this binding is independent of VDR's heterodimeric partner, the retinoid X receptor. Moreover, VDR appears to bind the GMCSF element as an apparent monomer in vitro. Protease digestion patterns of bound VDR, and receptor mutations affecting DNA binding and dimerization, demonstrate that the receptor binds to the negative site in a distinct conformation relative to a positive VDRE, suggesting that the DNA element itself acts as an allosteric effector of VDR function. This altered conformation may account for VDR's action as a repressing rather than activating factor at this locus.
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Affiliation(s)
- T L Towers
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Cornell University Graduate School of Medical Sciences, New York, New York 10021, USA
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Jensen TJ, Henriksen LO, Sølvsten H, Kragballe K. Inhibition of the 1,25-dihydroxyvitamin D3-induced increase in vitamin D receptor (VDR) levels and binding of VDR-retinoid X receptor (RXR) to a direct repeat (DR)-3 type response element by an RXR-specific ligand in human keratinocyte cultures. Biochem Pharmacol 1998; 55:767-73. [PMID: 9586948 DOI: 10.1016/s0006-2952(97)00580-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The biological active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), mediates most of its actions through the intracellular vitamin D receptor (VDR). VDR binds to vitamin D responsive elements (VDREs) in the promoter region of responsive genes and regulates transcription. Usually the VDREs consist of a direct repeat of two hexanucleotides spaced by three nucleotides (DR-3), to which VDR preferentially binds as a heterodimer with the retinoid X receptor (RXR). In the present study, we examined the effect of 1,25(OH)2D3 and a specific ligand for RXR, CD2809, on VDR and RXR levels in cultured human keratinocytes and on the binding of RXR-VDR to a DR-3 type response element. Incubation with 1,25(OH)2D3 increased VDR levels as determined by Western blotting, increased VDR-RXR binding to a DR-3 type response element as determined by the electromobility shift assay (EMSA), and induced the 25-OH-D3 24-hydroxylase (24-hydroxylase) gene, containing a DR-3 type response element. CD2809 caused a slight decrease in RXRalpha levels, but had no effect on VDR levels. Addition of both CD2809 and 1,25(OH)2D3 decreased VDR levels as well as the VDR-RXR binding levels to the DR-3 type response element, compared to 1,25(OH)2D3 alone. In conclusion, an RXR-specific ligand interferes with the 1,25(OH)2D3-induced stimulation of VDR levels and VDR-RXR binding to DNA in keratinocyte cultures. It is therefore possible that RXR-specific ligands may counteract certain biological actions of vitamin D3.
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Affiliation(s)
- T J Jensen
- Department of Dermatology, Marselisborg Hospital, Aarhus C, Denmark
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