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Peng X, Hawthorne M, Vaishnav A, St-Arnaud R, Mehta RG. 25-Hydroxyvitamin D3 is a natural chemopreventive agent against carcinogen induced precancerous lesions in mouse mammary gland organ culture. Breast Cancer Res Treat 2008; 113:31-41. [PMID: 18205042 DOI: 10.1007/s10549-008-9900-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 01/07/2008] [Indexed: 01/08/2023]
Abstract
Despite the role of vitamin D(3) endocrine system in prevention of mammary gland transformation in animal models, use of 1,25(OH)(2)D(3 )in clinical settings is precluded due to its toxicity in vivo. Therefore much effort has been placed in developing relatively non-toxic vitamin D analogs. Recently, with the discovery of the expression of 25-hydroxy vitamin D(3) 1alpha-hydroxylase (CYP27B1) in multiple extrarenal organs, the functional role of prohormone, 25-hydroxyvitamin D(3) [25(OH)D(3)], has been redefined. Since 25(OH)D(3) does not cause hypercalcemia and maintains relative high concentration in serum, it is possible that the prohormone can be converted to active hormone in mammary epithelial cells to provide chemopreventive effects. In the present study, we evaluated its functional significance using mouse mammary organ culture (MMOC) system. We first showed that 25(OH)D(3) 1alpha-hydroxylase is extensively expressed in mammary ductal epithelial cells at both protein and mRNA levels, which is a prerequisite for 25(OH)D(3) to function in an autocrine/paracrine manner. However, we also observed that clotrimazol (1alpha-hydroxylase inhibitor) enhanced 25(OH)D(3) -induced CYP24 expression in breast cancer cells. In mammary glands derived from 1alpha-hydroxylase knockout mice, 25(OH)D(3) treatment in organ culture significantly induced CYP24 expression, indicating a potential direct effect of 25(OH)D(3). In MMOC, 100-250 nM 25(OH)D(3) suppressed both ovarian hormone-dependent and -independent mammary precancerous lesions (induced by DMBA) by more than 50%, while the active hormone 1,25(OH)(2)D(3) (positive control) at 100 nM suppressed alveolar lesions by more than 80%. The inactive vitamin D(3) (negative control) at 100 nM suppressed alveolar lesions by only 20% (P>0.05). We found that 25(OH)D(3) inhibits DMBA-induced mammary alveolar lesions (MAL) in a stage-specific manner: 25(OH)D(3) mainly inhibits the promotion stage of lesion formation. We conclude that 25(OH)D(3) could serve as a non-toxic natural chemopreventive agent for further development for breast cancer prevention.
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Affiliation(s)
- Xinjian Peng
- IIT Research Institute, 10 West 35th Street, Chicago, IL 60616, USA
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2
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Wietrzyk J, Chodyński M, Fitak H, Wojdat E, Kutner A, Opolski A. Antitumor properties of diastereomeric and geometric analogs of vitamin D3. Anticancer Drugs 2007; 18:447-57. [PMID: 17351397 DOI: 10.1097/cad.0b013e3280143166] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Analogs of 1,25-dihydroxyvitamin D3 with a reversed configuration at C-1 or C-24 and E or Z geometry of the double bond at C-22 in the side chain or at C-5 in the triene system were examined for their antiproliferative activity in vitro against a spectrum of various human cancer cell lines. The analogs coded PRI-2201 (calcipotriol), PRI-2202 and PRI-2205, such as calcitriol and tacalcitol (used as a referential agents), revealed antiproliferative activity against human HL-60, HL-60/MX2, MCF-7, T47D, SCC-25 and mouse WEHI-3 cancer cell lines. The toxicity studies in vivo showed that PRI-2202 and PRI-2205 are less toxic than referential agents. Even at total doses of 2.5-5.0 mg/kg distributed during 5 successive days, no changes in body weight were observed. Calcitriol and tacalcitol showed toxicity in the same protocol at 100 times lower doses. Calcipotriol was lethal to all mice after administration of a total dose of 5.0 mg/kg. The analog PRI-2205 appeared to be more active in mouse Levis lung cancer tumor growth inhibition than calcitriol, calcipotriol or PRI-2202. This analog did not reveal calcemic activity at doses which inhibit tumor growth in vivo nor at higher doses.
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Affiliation(s)
- Joanna Wietrzyk
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław bPharmaceutical Research Institute, Warsaw, Poland.
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3
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Cho YM, Choi H, Hwang IH, Kim YK, Myung KH. Effects of 25-hydroxyvitamin D3 and manipulated dietary cation-anion difference on the tenderness of beef from cull native Korean cows. J Anim Sci 2006; 84:1481-8. [PMID: 16699104 DOI: 10.2527/2006.8461481x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, we characterized the effects of 25-hydroxyvitamin D3 (25-OH D3) and manipulated dietary cation-anion difference (DCAD) on the performance, urine pH, serum constituents, carcass traits, tissue residual vitamin D and its metabolites, beef tenderness, and mRNA and protein concentrations of Ca-dependent proteinases in LM using 24 cull native Korean cows. The cows were divided into 3 groups of 8: control, 25-OH D3 supplemented (25-OH D3), and manipulated DCAD plus 25-OH D3 supplemented (DCAD+25-OH D3). Cows receiving 25-OH D3 or DCAD+25-OH D3 were dosed with 125 mg of 25-OH D3 6 d before slaughter. The manipulated DCAD (-10 mEq/100 g of DM) diet was fed from 20 to 6 d (14 d) before slaughter. The DCAD+25-OH D3 treatment decreased urine pH and increased serum Ca concentrations. Although the vitamin D concentrations in LM, liver, and kidney were not affected by 25-OH D3 or DCAD+25-OH D3, muscle tissue 25-OH D3 concentrations were increased by both regimens. Serum 25-OH D3 concentrations were increased by 25-OH D3 supplementation, and the increase was even greater for DCAD+25-OH D3. The same pattern was observed for serum 1,25- (OH)2 D3. However, the LM concentration of 1,25-(OH)2 D3 was less for DCAD+25-OH D3 than for control. Although Ca concentrations of LM increased numerically in response to 25-OH D3 supplementation, no statistical differences in Warner-Bratzler shear force or sensory traits of LM were detected. The LM of cows receiving 25-OH D3 with or without manipulated DCAD had greater concentrations of mu-calpain and m-calpain mRNA, whereas the reverse was observed for calpastatin mRNA. Expression of mu-calpain protein was increased relative to control by DCAD+25-OH D3. The amount of 25-OH D3 and manipulated DCAD administered to cull native Korean cows was insufficient to improve tenderness of beef by increasing muscle Ca concentration. However, DCAD+25-OH D3 induced greater expressions of mu-calpain protein as well as mRNA.
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Affiliation(s)
- Y M Cho
- Hanwoo Experiment Station, National Livestock Research Institute, Pyungchang, Gangwon 232-950, Korea
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4
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Brailoiu E, Churamani D, Pandey V, Brailoiu GC, Tuluc F, Patel S, Dun NJ. Messenger-specific role for nicotinic acid adenine dinucleotide phosphate in neuronal differentiation. J Biol Chem 2006; 281:15923-8. [PMID: 16595650 DOI: 10.1074/jbc.m602249200] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cells possess several Ca2+-mobilizing messengers, which couple stimulation at the cell surface by a multitude of extracellular cues to the regulation of intracellular Ca2+-sensitive targets. Recent studies suggest that agonists differentially select from this molecular palette to generate their characteristic Ca2+ signals but it is still unclear whether different messengers mediate different functions or whether they act in a redundant fashion. In this study, we compared the effects of nicotinic acid adenine dinucleotide phosphate (NAADP), a novel Ca2+-mobilizing messenger, with that of the prototypical messenger inositol trisphosphate on cytosolic Ca2+ levels and differentiation status of PC12 cells. We demonstrate that liposomal delivery of NAADP mediated release of Ca2+ from acidic Ca2+ stores and that this stimulus was sufficient to drive differentiation of the cells to a neuronal-like phenotype. In sharp contrast, cell fate was unaffected by more transient Ca2+ signals generated by inositol trisphosphate-evoked release of endoplasmic reticulum Ca2+ stores. Our data establish for the first time (i) the presence of novel NAADP-sensitive Ca2+ stores in PC12 cells, (ii) a role for NAADP in differentiation, and (iii) that Ca2+-dependent function can be messenger-specific. Thus, differential recruitment of intracellular Ca2+-mobilizing messengers and their target Ca2+ stores may represent a robust means of maintaining stimulus fidelity in the control of Ca2+-dependent cell function.
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Affiliation(s)
- Eugen Brailoiu
- Department of Pharmacology, Temple University Medical School, Philadelphia, Pennsylvania, USA
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5
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Montgomery JL, King MB, Gentry JG, Barham AR, Barham BL, Hilton GG, Blanton JR, Horst RL, Galyean ML, Morrow KJ, Wester DB, Miller MF. Supplemental vitamin D3 concentration and biological type of steers. II. Tenderness, quality, and residues of beef. J Anim Sci 2005; 82:2092-104. [PMID: 15309957 DOI: 10.2527/2004.8272092x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vitamin D3 was orally supplemented to determine the supplemental dose that improved beef tenderness in different cattle breed types. Feedlot steers (n = 142) were arranged in a 4 x 3 factorial arrangement consisting of four levels of supplemental vitamin D3 (0, 0.5, 1, and 5 million IU/steer daily) administered for eight consecutive days antemortem using three biological types (Bos indicus, Bos Taurus-Continental, and Bos Taurus-English). Warner-Bratzler shear force (WBSF) was measured at 3, 7, 10, 14, and 21 d postmortem, and trained sensory analysis was conducted at 7 d postmortem on LM, semimembranosus, gluteus medius, and supraspinatus steaks. Concentrations of vitamin D3 and the metabolites 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 were determined in the LM, liver, kidney, and plasma. Biological type of cattle did not interact (P > 0.10) with vitamin D3 supplementation for sensory or tenderness traits, suggesting that feeding vitamin D3 for 8 d before slaughter affected the different biological types of cattle similarly. Supplementing steers with 0.5, 1, or 5 million IU/(steer(d) decreased (P < 0.05) LM WBSF at 7, 10, 14, and 21 d postmortem compared with controls, and vitamin D3 treatments of 0.5, 1, and 5 million IU decreased (P < 0.05) semimembranosus WBSF at 3, 7, and 14 d postmortem. In general, vitamin D3-induced improvements in WBSF were most consistent and intense in LM steaks. Sensory panel tenderness was improved (P < 0.05) by all vitamin D3 treatments in LM steaks. Sensory traits ofjuiciness, flavor, connective tissue, and off-flavor were not (P > 0.05) affected by vitamin D3 treatments. All vitamin D3 treatments decreased micro-calpain activity and increased muscle Ca concentrations (P < 0.05). Vitamin D3 concentrations were increased (P < 0.05) by supplementation in all tissues tested (liver, kidney, LM, and plasma); however, cooking steaks to 71 degrees C decreased (P < 0.05) treatment residue effects. The vitamin D metabolite 1,25-dihydroxyvitamin D3 was increased (P < 0.05) only in plasma samples as a result of the vitamin D3 treatments. These results indicate that supplementation with vitamin D3 at 0.5 million IU/steer daily for eight consecutive days before slaughter improved tenderness in steaks from different subprimal cuts by affecting muscle Ca concentrations, micro-calpain activities, and muscle proteolysis, with only a small effect on tissue residues of vitamin D3.
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Affiliation(s)
- J L Montgomery
- Department of Animal and Food Science, Texas Tech University, Lubbock, TX 79409, USA
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6
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Hughes PJ, Steinmeyer A, Chandraratna RAS, Brown G. 1?,25-dihydroxyvitamin D3 stimulates steroid sulphatase activity in HL60 and NB4 acute myeloid leukaemia cell lines by different receptor-mediated mechanisms. J Cell Biochem 2005; 94:1175-89. [PMID: 15696548 DOI: 10.1002/jcb.20377] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Steroid sulphatase is a key enzyme in the biosynthesis of bioactive estrogens and androgens from highly abundant inactive circulating sulphated steroid precursors. Little is known about how the expression/activity of this enzyme is regulated. In this article, we show that of 1alpha,25(OH)2D3 stimulates an increase steroid sulphatase activity in the HL60 myeloid leukaemic cell line that is inhibited by a specific nuclear VDR (VDRnuc) antagonist and unaffected by plasma membrane-associated vitamin D receptor (VDRmem) agonists and antagonists. 1alpha,25(OH)2D3-mediated up-regulation of steroid sulphatase activity in HL60 cells was augmented by RXR agonists, blocked by RXR-specific antagonists, and RAR specific agonists and antagonists had no effect. In contrast, the 1alpha,25(OH)2D3-mediated up-regulation of steroid sulphatase activity in the NB4 myeloid leukaemic cell line was unaffected by the specific VDRnuc and RXR antagonists, but was blocked by a VDRmem-specific antagonist and was increased by VDRmem-specific agonists. The findings reveal that VDRnuc-RXR-heterodimers play a key role in the 1alpha,25(OH)2D3-mediated up-regulation of steroid sulphatase activity in HL60 cells. However, in NB4 cells, VDRnuc-derived signals do not play an obligatory role, and non-genomic VDRmem-derived signals are important.
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Affiliation(s)
- Philip J Hughes
- Division of Immunity and Infection, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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7
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Watson CS, Gametchu B. Proteins of multiple classes may participate in nongenomic steroid actions. Exp Biol Med (Maywood) 2004; 228:1272-81. [PMID: 14681543 PMCID: PMC1224708 DOI: 10.1177/153537020322801106] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Responses to steroids initiated from non-nuclear receptors impinge on a wide variety of cellular responses and utilize nearly all known signal transduction webs. While the mechanisms by which steroid receptors localize in the membrane are still unclear, it is apparent that this alternative localization allows steroid receptors to participate in a wide range of complex functions influencing cell proliferation, death, and differentiation. The central debate still remains the identity of the protein class or classes that mediate membrane-initiated (nongenomic) responses. The data thus far have supported several possibilities, including: nuclear steroid receptor-like forms in non-nuclear locations; other known (nonsteroid) membrane receptors or channels with additional steroid-binding sites; enzymes; transporters; receptors for serum steroid-binding proteins; unique and previously undescribed proteins; or chimeras of typical steroid receptor domains with other unique or known protein domains. Categorizing membrane steroid receptor proteins based exclusively on the actions of antagonists and agonists, without considering cell context and protein partnering issues, may mislead us into predicting more receptor subtypes than really exist. However, the plethora of signaling and functional outcomes may indicate the participation of more than one kind of steroid-binding protein. Resolving such unanswered questions will require future investigative focus on this alternative arm of steroid action, which is likely to yield as many therapeutic opportunities as have nuclear steroid mechanisms.
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Affiliation(s)
- Cheryl S Watson
- Department of Human Biological Chemistry and Genetics, University of Texas, Medical Branch, Galveston, Texas 77555, USA.
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8
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Funato K, Miyazawa K, Yaguchi M, Gotoh A, Ohyashiki K. Combination of 22-oxa-1,25-dihydroxyvitamin D(3), a vitamin D(3) derivative, with vitamin K(2) (VK2) synergistically enhances cell differentiation but suppresses VK2-inducing apoptosis in HL-60 cells. Leukemia 2002; 16:1519-27. [PMID: 12145693 DOI: 10.1038/sj.leu.2402614] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2001] [Accepted: 04/17/2002] [Indexed: 11/09/2022]
Abstract
We originally reported that vitamin K(2) (VK2) effectively induces apoptosis in various types of primary cultured leukemia cells and leukemia cell lines in vitro. In addition, VK2 was shown to induce differentiation of leukemia cells when the cells were resistant against VK2-inducing apoptosis. A novel synthetic vitamin D(3)derivative, 22-oxa-1,25-dihydroxyvitamin D(3) (OCT: oxacarcitriol) shows a more potent differentiation-inducing ability among myeloid leukemia cells in vitro with much lesser extent of the induction of hypercalcemia in vivo as compared to the effects of 1alpha,25(OH)(2)D(3). In the present study, we focused on the effects of a combination of OCT plus VK2 on leukemia cells. Treatment of HL-60 cells with OCT for 72 h induces monocytic differentiation. A combination of OCT plus VK2 dramatically enhances monocytic differentiation as assessed by morphologic features, positivity for non-specific esterase staining, and cell surface antigen expressions. This combined effect far exceeds the maximum differentiation induction ability at the optimal concentrations of either OCT or VK2 alone. In addition, pronounced accumulation of the cells in the G0/G1 phase is observed by combined treatment with OCT plus VK2 as compared with each vitamin alone. In contrast to cell differentiation, caspase-3 activation and apoptosis induction in response to VK2 are significantly suppressed in the presence of OCT in HL-60 cells. These data suggest that monocytic differentiation and apoptosis induction of HL-60 cells are inversely regulated. Furthermore, pronounced induction of differentiation by combined treatment with VK2 plus OCT was also observed in four out of six cases of primary cultured acute myeloid leukemia cells in vitro, suggesting that VK2 plus OCT might be a potent combination for the differentiation-based therapy for acute myeloid leukemias.
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Affiliation(s)
- K Funato
- First Department of Internal Medicine (Hematology/Oncology), Tokyo Medical University, Tokyo, Japan
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9
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Ji Y, Wang X, Donnelly RJ, Uskokovic MR, Studzinski GP. Signaling of monocytic differentiation by a non-hypercalcemic analog of vitamin D3, 1,25(OH)2-5,6 trans-16-ene-vitamin D3, involves nuclear vitamin D receptor (nVDR) and non-nVDR-mediated pathways. J Cell Physiol 2002; 191:198-207. [PMID: 12064463 DOI: 10.1002/jcp.10091] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Exposure of leukemia cells to the physiologically active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25D3) normalizes their phenotype to cells that resemble mature monocytes. One of the earliest detectable events in this process is an upregulation of the nuclear receptor for 1,25D3, the vitamin D receptor (nVDR). In contrast, the novel analog of 1,25D3, 1,25-dihydroxy-5,6 trans-16-ene-vitamin D3 (5,6-16D3), which has recently been reported to have low calcium-mobilizing activity in vivo, rapidly induced the expression of CD14, CD11b, and monocyte-specific esterase (MSE), classical markers of the mature monocyte, but upregulated nVDR expression less than 1,25D3. This upregulation was shown to be the result of altered degradation of the nVDR protein, while the levels of nVDR mRNA were constant. Knock-out of nVDR transcriptional activity by a decoy VDRE double-stranded deoxyoligonucleotide, markedly abrogated 1,25D3-induced differentiation, but incompletely inhibited 5,6-16D3-induced differentiation. These findings suggest that the unique ability of 5,6-16D3 to induce cell differentiation but not systemic hypercalcemia, may be due to the activation of pathways which initiate differentiation independently of nVDR.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Calcitriol/adverse effects
- Calcitriol/analogs & derivatives
- Calcitriol/pharmacology
- Calcitriol/therapeutic use
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cell Transformation, Neoplastic/drug effects
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation/drug effects
- Down-Regulation/physiology
- Humans
- Leukemia, Myeloid/drug therapy
- Leukemia, Myeloid/metabolism
- Leukemia, Myeloid/physiopathology
- Monocytes/cytology
- Monocytes/drug effects
- Monocytes/metabolism
- Oligonucleotides/pharmacology
- Protein Binding/drug effects
- Protein Binding/physiology
- Receptors, Calcitriol/drug effects
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Tumor Cells, Cultured
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
- Yan Ji
- Department of Pathology and Laboratory Medicine, UMD-New Jersey Medical School, Newark 07103, USA
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10
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Roig EA, Richer E, Canonne‐Hergaux F, Gros P, Cellier MFM. Regulation of
NRAMP1
gene expression by 1α,25‐dihydroxy‐vitamin D
3
in HL‐60 phagocytes. J Leukoc Biol 2002. [DOI: 10.1189/jlb.71.5.890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- E. A. Roig
- INRS‐Institut Armand‐Frappier, Laval, PQ, Canada; and
| | - E. Richer
- INRS‐Institut Armand‐Frappier, Laval, PQ, Canada; and
| | | | - P. Gros
- Department of Biochemistry, McGill University, Montréal, PQ, Canada
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11
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Berry DM, Clark CS, Meckling-Gill KA. 1alpha,25-dihydroxyvitamin D3 stimulates phosphorylation of IkappaBalpha and synergizes with TPA to induce nuclear translocation of NFkappaB during monocytic differentiation of NB4 leukemia cells. Exp Cell Res 2002; 272:176-84. [PMID: 11777342 DOI: 10.1006/excr.2001.5410] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Treatment of NB4 acute promyelocytic leukemia cells with 1,25-dihydroxyvitamin D3 (1,25D3) or analogs 20-epi-22-oxa-24a,26a,27a-trihomo-1alpha,25-dihydroxyvitamin D3, 1,24-dihydroxy-22-ene-24-cyclopropylvitamin D3, 1alpha,25-dihydroxylumisterol3, or 1alpha,25(OH)2-d5-previtamin D3 in combination with TPA induces monocytic differentiation. The role of 1,25D3 in the induction of maturation has been shown to be a priming effect. Differentiation in response to these agents requires VDR-independent signaling of 1,25D3, PKC signaling, intracellular calcium, and calpain activity. In this study we identify the NFkappaB/IkappaB signaling pathway as a target of 1,25D3 and TPA action. One of the priming effects of 1,25D3 appears to be the rapid phosphorylation of serine residues on IkappaBalpha. On their own, 1,25D3, its analogs, and TPA do not alter IkappaBalpha expression; however, combinations of analogs with TPA result in a synergistic decrease in IkappaBalpha expression. Decreased expression of IkappaBalpha likely results from enhanced degradation, which allows the observed subsequent nuclear translocation of NFkappaB subunit p65. Since nuclear-localized NFkappaB was observed only in combination-treated cells, it is proposed that nuclear targets of NFkappaB are required for monocytic differentiation. Intracellular calcium and proteolytic activity are both necessary for the induction of IkappaB regulation and translocation of NFkappaB and are critical components of the nongenomic signaling cascades of the 1,25D3-induced differentiation pathway.
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Affiliation(s)
- Donna M Berry
- Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario NIG 2W1, Canada
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12
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Norman AW, Henry HL, Bishop JE, Song XD, Bula C, Okamura WH. Different shapes of the steroid hormone 1alpha,25(OH)(2)-vitamin D(3) act as agonists for two different receptors in the vitamin D endocrine system to mediate genomic and rapid responses. Steroids 2001; 66:147-58. [PMID: 11179722 DOI: 10.1016/s0039-128x(00)00165-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vitamin D(3) produces biologic responses as a consequence of its metabolism into 1alpha,25(OH)(2)-vitamin D(3) [1alpha,25(OH)(2)D(3)] and 24R,25(OH)(2)-vitamin D(3). The metabolic production of these two seco steroids and their generation of the plethora of biologic actions that are attributable to the parent vitamin D(3) are orchestrated via the integrated operation of the vitamin D endocrine system. This system is very similar in its organization to that of classic endocrine systems and is characterized by an endocrine gland (the kidney, the source of the two steroid hormones), target cells which possess receptors for the steroid hormones, and a feed-back loop involving changes in serum Ca(2+) that alter the secretion of parathyroid hormone (a stimulator of the renal 1-hydroxylase) which modulates the output by the kidney of the steroid hormones. There are, however, at least two unique aspects to the vitamin D endocrine system. (a) The chemical structures of vitamin D and its steroid hormones dictate that these be highly conformationally flexible molecules present a wide variety of shapes to their biologic environments. (b) It is now believed that 1alpha,25(OH)(2)D(3) produces biologic responses through two distinct receptors which recognize totally different shapes of the conformationally flexible 1alpha,25(OH)(2)D(3). Thus, the classic actions of 1alpha,25(OH)(2)D(3) to regulate gene transcription occur as a consequence of the stereospecific interaction of a modified 6-s-trans bowl-shape of 1alpha,25(OH)(2)D(3) with its nuclear receptor (VDR(nuc)). The ability of 1alpha,25(OH)(2)D(3) to generate a variety of rapid (seconds to minutes) biologic responses (opening of chloride channels, activation of PKC and MAP kinases) requires a planar 6-s-cis ligand shape which is recognized by a putative plasma membrane receptor (VDR(mem)) to initiate appropriate signal transduction pathways. This report summarizes the evidence for the specificity of different ligand shapes and the operation of the two receptor families for 1alpha,25(OH)(2)D(3).
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Affiliation(s)
- A W Norman
- Department of Biochemistry, University of California, Riverside 92521, USA.
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