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Kawagoe F, Mototani S, Yasuda K, Takeuchi A, Mano H, Kakuda S, Saitoh H, Sakaki T, Kittaka A. Synthesis of (22 R)-, (22 S)-22-Fluoro-, and 22,22-Difluoro-25-hydroxyvitamin D 3 and Effects of Side-Chain Fluorination on Biological Activity and CYP24A1-Dependent Metabolism. J Org Chem 2023; 88:12394-12408. [PMID: 37590101 DOI: 10.1021/acs.joc.3c01134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Three novel analogues of C22-fluoro-25-hydroxyvitamin D3 (5-7) were synthesized and evaluated to investigate the effects of side-chain fluorination on biological activity and metabolism of vitamin D. These novel analogues were constructed by convergent synthesis applying the Wittig-Horner coupling reaction between CD-ring ketones (41,42,44) and A-ring phosphine oxide (11). The introduction of C22-fluoro units was achieved by stereoselective deoxy-fluorination for synthesizing 5 and 6 or two-step cationic fluorination for 7. The absolute configuration of the C22-fluoro-8-oxo-CD-ring (39) was confirmed by X-ray crystallographic structure determination. The basic biological activity of the side-chain fluorinated analogues, including compounds (5-7), was evaluated. Generally, osteocalcin promoter transactivation activity decreased in the order of C24-fluoro, C23-fluoro, and C22-fluoro analogues. In addition, the metabolic stability of C22-fluoro-25-hydroxyvitamin D3 (5-7) against hCYP24A1 metabolism was also evaluated. 22,22-Difluoro-25(OH)D3 (7) was more stable against hCYP24A1 metabolism compared with its non-fluorinated counterpart 25-hydroxyvitamin D3 (1), but fluorination at the C22 position had little effect on the metabolic stability compared with C24- and C23-fluoro analogues. Our research clarified that side-chain fluorination in vitamin D markedly changes CYP24A1 metabolic stability depending on the fluorinating position.
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Affiliation(s)
- Fumihiro Kawagoe
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Sayuri Mototani
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Akiko Takeuchi
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Hiroki Mano
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Shinji Kakuda
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Hiroshi Saitoh
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Toshiyuki Sakaki
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
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Kawagoe F, Mototani S, Yasuda K, Mano H, Takeuchi A, Saitoh H, Sakaki T, Kittaka A. Synthesis of New 26,27-Difluoro- and 26,26,27,27-Tetrafluoro-25-hydroxyvitamin D 3: Effects of Terminal Fluorine Atoms on Biological Activity and Half-life. Chem Pharm Bull (Tokyo) 2023; 71:717-723. [PMID: 37423740 DOI: 10.1248/cpb.c23-00395] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
As an extension of our research on providing a chemical library of side-chain fluorinated vitamin D3 analogues, we newly designed and synthesized 26,27-difluoro-25-hydroxyvitamin D3 (1) and 26,26,27,27-tetrafluoro-25-hydroxyvitamin D3 (2) using a convergent method applying the Wittig-Horner coupling reaction between CD-ring ketones (13, 14) and A-ring phosphine oxide (5). The basic biological activities of analogues, 1, 2, and 26,26,26,27,27,27-hexafluoro-25-hydroxyvitamin D3 [HF-25(OH)D3] were examined. Although the tetrafluorinated new compound 2 exhibited higher binding affinity for vitamin D receptor (VDR) and resistance to CYP24A1-dependent metabolism compared with the difluorinated 1 and its non-fluorinated counterpart 25-hydroxyvitamin D3 [25(OH)D3], HF-25(OH)D3 showed the highest activity among these compounds. Osteocalcin promoter transactivation activity of these fluorinated analogues was tested, and it decreased in the order of HF-25(OH)D3, 2, 1, and 25(OH)D3 in which HF-25(OH)D3 showed 19-times greater activity than the natural 25(OH)D3.
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Affiliation(s)
| | | | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University
| | - Hiroki Mano
- Faculty of Engineering, Toyama Prefectural University
| | - Akiko Takeuchi
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd
| | - Hiroshi Saitoh
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd
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The First Convergent Synthesis of 23,23-Difluoro-25-hydroxyvitamin D 3 and Its 24-Hydroxy Derivatives: Preliminary Assessment of Biological Activities. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27165352. [PMID: 36014588 PMCID: PMC9415778 DOI: 10.3390/molecules27165352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022]
Abstract
In this paper, we report an efficient synthetic route for the 23,23-difluoro-25-hydroxyvitamin D3 (5) and its 24-hydroxylated analogues (7,8), which are candidates for the CYP24A1 main metabolites of 5. The key fragments, 23,23-difluoro-CD-ring precursors (9-11), were synthesized starting from Inhoffen-Lythgoe diol (12), and introduction of the C23 difluoro unit to α-ketoester (19) was achieved using N,N-diethylaminosulfur trifluoride (DAST). Preliminary biological evaluation revealed that 23,23-F2-25(OH)D3 (5) showed approximately eight times higher resistance to CYP24A1 metabolism and 12 times lower VDR-binding affinity than its nonfluorinated counterpart 25(OH)D3 (1).
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Jay N, Duffy SR, Estrada DF. Characterization of a Cleavable Fusion of Human CYP24A1 with Adrenodoxin Reveals the Variable Role of Hydrophobics in Redox Partner Binding. Biochemistry 2022; 61:57-66. [PMID: 34979083 DOI: 10.1021/acs.biochem.1c00770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The improper maintenance of the bioactivated form of vitamin-D (1α,25(OH)2D) may result in vitamin-D insufficiency and therefore compromise the absorption of dietary calcium. A significant regulator of vitamin-D metabolism is the inactivating function of the mitochondrial enzyme cytochrome P450 24A1 (CYP24A1). In humans, CYP24A1 carries out hydroxylation of carbon-23 (C23) or carbon-24 (C24) of the 1α,25(OH)2D side chain, eventually resulting in production of either an antagonist of the vitamin-D receptor (C23 pathway) or calcitroic acid (C24 pathway). Despite its importance to human health, the human isoform (hCYP24A1) remains largely uncharacterized due in part to the difficulty in producing the enzyme using recombinant means. In this study, we utilize a cleavable fusion with the cognate redox partner, human Adx (hAdx), to stabilize hCYP24A1 during production. The subsequent cleavage and isolation of active hCYP24A1 allowed for an investigation of substrate and analog binding, enzymatic activity, and redox partner recognition. We demonstrate involvement of a nonpolar contact involving Leu-80 of hAdx and a nonconserved proximal surface of hCYP24A1. Interestingly, shortening the length of this residue (L80V) results in enhanced binding between the CYP-Adx complex and 1α,25(OH)2D yet unexpectedly results in decreased catalysis. The same mutation has a negligible effect on rat CYP24A1 (a C24-hydroxylase), indicating the presence of a species-specific requirement that may correlate with differences in regioselectivity of the reaction. Taken together, this work presents an example of production of a challenging human CYP as well as providing details regarding hydrophobic modulation of a CYP-Adx complex that is critical to human vitamin-D metabolism.
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Affiliation(s)
- Natalie Jay
- Department of Biochemistry, University at Buffalo, Buffalo, New York 14203, United States
| | - Sean R Duffy
- Department of Biochemistry, University at Buffalo, Buffalo, New York 14203, United States
| | - D Fernando Estrada
- Department of Biochemistry, University at Buffalo, Buffalo, New York 14203, United States
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Kawagoe F, Mototani S, Yasuda K, Mano H, Sakaki T, Kittaka A. Stereoselective Synthesis of 24-Fluoro-25-Hydroxyvitamin D 3 Analogues and Their Stability to hCYP24A1-Dependent Catabolism. Int J Mol Sci 2021; 22:ijms222111863. [PMID: 34769295 PMCID: PMC8584271 DOI: 10.3390/ijms222111863] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/18/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Two 24-fluoro-25-hydroxyvitamin D3 analogues (3,4) were synthesized in a convergent manner. The introduction of a stereocenter to the vitamin D3 side-chain C24 position was achieved via Sharpless dihydroxylation, and a deoxyfluorination reaction was utilized for the fluorination step. Comparison between (24R)- and (24S)-24-fluoro-25-hydroxyvitamin D3 revealed that the C24-R-configuration isomer 4 was more resistant to CYP24A1-dependent metabolism than its 24S-isomer 3. The new synthetic route of the CYP24A1 main metabolite (24R)-24,25-dihydroxyvitamin D3 (6) and its 24S-isomer (5) was also studied using synthetic intermediates (30,31) in parallel.
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Affiliation(s)
- Fumihiro Kawagoe
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Tokyo 173-8605, Japan; (F.K.); (S.M.)
| | - Sayuri Mototani
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Tokyo 173-8605, Japan; (F.K.); (S.M.)
| | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan; (K.Y.); (H.M.); (T.S.)
| | - Hiroki Mano
- Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan; (K.Y.); (H.M.); (T.S.)
| | - Toshiyuki Sakaki
- Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan; (K.Y.); (H.M.); (T.S.)
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Tokyo 173-8605, Japan; (F.K.); (S.M.)
- Correspondence: ; Tel.: +81-3-3964-8109; Fax: +81-3-3964-8117
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Yasuda K, Nishikawa M, Mano H, Takano M, Kittaka A, Ikushiro S, Sakaki T. Development of In Vitro and In Vivo Evaluation Systems for Vitamin D Derivatives and Their Application to Drug Discovery. Int J Mol Sci 2021; 22:ijms222111839. [PMID: 34769269 PMCID: PMC8584323 DOI: 10.3390/ijms222111839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/30/2022] Open
Abstract
We have developed an in vitro system to easily examine the affinity for vitamin D receptor (VDR) and CYP24A1-mediated metabolism as two methods of assessing vitamin D derivatives. Vitamin D derivatives with high VDR affinity and resistance to CYP24A1-mediated metabolism could be good therapeutic agents. This system can effectively select vitamin D derivatives with these useful properties. We have also developed an in vivo system including a Cyp27b1-gene-deficient rat (a type I rickets model), a Vdr-gene-deficient rat (a type II rickets model), and a rat with a mutant Vdr (R270L) (another type II rickets model) using a genome editing method. For Cyp27b1-gene-deficient and Vdr mutant (R270L) rats, amelioration of rickets symptoms can be used as an index of the efficacy of vitamin D derivatives. Vdr-gene-deficient rats can be used to assess the activities of vitamin D derivatives specialized for actions not mediated by VDR. One of our original vitamin D derivatives, which displays high affinity VDR binding and resistance to CYP24A1-dependent metabolism, has shown good therapeutic effects in Vdr (R270L) rats, although further analysis is needed.
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Affiliation(s)
- Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (M.N.); (S.I.)
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
| | - Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan; (M.T.); (A.K.)
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan; (M.T.); (A.K.)
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (M.N.); (S.I.)
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu 939-0398, Toyama, Japan; (K.Y.); (H.M.)
- Correspondence:
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7
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Yasuda K, Nishikawa M, Okamoto K, Horibe K, Mano H, Yamaguchi M, Okon R, Nakagawa K, Tsugawa N, Okano T, Kawagoe F, Kittaka A, Ikushiro S, Sakaki T. Elucidation of metabolic pathways of 25-hydroxyvitamin D3 mediated by CYP24A1 and CYP3A using Cyp24a1 knockout rats generated by CRISPR/Cas9 system. J Biol Chem 2021; 296:100668. [PMID: 33865853 PMCID: PMC8134072 DOI: 10.1016/j.jbc.2021.100668] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/25/2021] [Accepted: 04/13/2021] [Indexed: 01/27/2023] Open
Abstract
CYP24A1-deficient (Cyp24a1 KO) rats were generated using the CRISPER/Cas9 system to investigate CYP24A1-dependent or -independent metabolism of 25(OH)D3, the prohormone of calcitriol. Plasma 25(OH)D3 concentrations in Cyp24a1 KO rats were approximately twofold higher than in wild-type rats. Wild-type rats showed five metabolites of 25(OH)D3 in plasma following oral administration of 25(OH)D3, and these metabolites were not detected in Cyp24a1 KO rats. Among these metabolites, 25(OH)D3-26,23-lactone was identified as the second major metabolite with a significantly higher Tmax value than others. When 23S,25(OH)2D3 was administered to Cyp24a1 KO rats, neither 23,25,26(OH)3D3 nor 25(OH)D3-26,23-lactone was observed. However, when 23S,25R,26(OH)3D3 was administered to Cyp24a1 KO rats, plasma 25(OH)D3-26,23-lactone was detected. These results suggested that CYP24A1 is responsible for the conversion of 25(OH)D3 to 23,25,26(OH)3D3 via 23,25(OH)2D3, but enzyme(s) other than CYP24A1 may be involved in the conversion of 23,25,26(OH)3D3 to 25(OH)D3-26,23-lactone. Enzymatic studies using recombinant human CYP species and the inhibitory effects of ketoconazole suggested that CYP3A plays an essential role in the conversion of 23,25,26(OH)3D3 into 25(OH)D3-26,23-lactone in both rats and humans. Taken together, our data indicate that Cyp24a1 KO rats are valuable for metabolic studies of vitamin D and its analogs. In addition, long-term administration of 25(OH)D3 to Cyp24a1 KO rats at 110 μg/kg body weight/day resulted in significant weight loss and ectopic calcification. Thus, Cyp24a1 KO rats could represent an important model for studying renal diseases originating from CYP24A1 dysfunction.
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Affiliation(s)
- Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kairi Okamoto
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kyohei Horibe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Mana Yamaguchi
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Risa Okon
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Kimie Nakagawa
- Laboratory of Hygienic Sciences, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Chuo-ku, Kobe, Japan
| | - Naoko Tsugawa
- Department of Health and Nutrition, Faculty of Health and Nutrition, Osaka Shoin Women's University, Higashi-Osaka, Japan
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, Higashinada-ku, Kobe, Japan
| | - Fumihiro Kawagoe
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan.
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Nishikawa M, Yasuda K, Takamatsu M, Abe K, Okamoto K, Horibe K, Mano H, Nakagawa K, Tsugawa N, Hirota Y, Horie T, Hinoi E, Okano T, Ikushiro S, Sakaki T. Generation of novel genetically modified rats to reveal the molecular mechanisms of vitamin D actions. Sci Rep 2020; 10:5677. [PMID: 32231239 PMCID: PMC7105495 DOI: 10.1038/s41598-020-62048-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 02/18/2020] [Indexed: 11/09/2022] Open
Abstract
Recent studies have suggested that vitamin D activities involve vitamin D receptor (VDR)-dependent and VDR-independent effects of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 25-hydroxyvitamin D3 (25(OH)D3) and ligand-independent effects of the VDR. Here, we describe a novel in vivo system using genetically modified rats deficient in the Cyp27b1 or Vdr genes. Type II rickets model rats with a mutant Vdr (R270L), which recognizes 1,25(OH)2D3 with an affinity equivalent to that for 25(OH)D3, were also generated. Although Cyp27b1-knockout (KO), Vdr-KO, and Vdr (R270L) rats each showed rickets symptoms, including abnormal bone formation, they were significantly different from each other. Administration of 25(OH)D3 reversed rickets symptoms in Cyp27b1-KO and Vdr (R270L) rats. Interestingly, 1,25(OH)2D3 was synthesized in Cyp27b1-KO rats, probably by Cyp27a1. In contrast, the effects of 25(OH)D3 on Vdr (R270L) rats strongly suggested a direct action of 25(OH)D3 via VDR-genomic pathways. These results convincingly suggest the usefulness of our in vivo system.
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Affiliation(s)
- Miyu Nishikawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Masashi Takamatsu
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Keisuke Abe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kairi Okamoto
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kyohei Horibe
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Hiroki Mano
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kimie Nakagawa
- Department of Hygienic Sciences, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Naoko Tsugawa
- Department of Health and Nutrition, Faculty of Health and Nutrition, Osaka Shoin Women's University, 4-2-26 Hishiya-nishi, Higashi-Osaka, 577-8550, Japan
| | - Yoshihisa Hirota
- Laboratory of Biochemistry, Faculty of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, 337-8570, Japan
| | - Tetsuhiro Horie
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan
| | - Eiichi Hinoi
- Laboratory of Pharmacology, Department of Bioactive Molecules, Gifu Pharmaceutical University, Gifu, Japan.,United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan
| | - Toshio Okano
- Department of Hygienic Sciences, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, 658-8558, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
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Al-Zohily B, Al-Menhali A, Gariballa S, Haq A, Shah I. Epimers of Vitamin D: A Review. Int J Mol Sci 2020; 21:ijms21020470. [PMID: 31940808 PMCID: PMC7013384 DOI: 10.3390/ijms21020470] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 12/12/2022] Open
Abstract
In this review, we discuss the sources, formation, metabolism, function, biological activity, and potency of C3-epimers (epimers of vitamin D). We also determine the role of epimerase in vitamin D-binding protein (DBP) and vitamin D receptors (VDR) according to different subcellular localizations. The importance of C3 epimerization and the metabolic pathway of vitamin D at the hydroxyl group have recently been recognized. Here, the hydroxyl group at the C3 position is orientated differently from the alpha to beta orientation in space. However, the details of this epimerization pathway are not yet clearly understood. Even the gene encoding for the enzyme involved in epimerization has not yet been identified. Many published research articles have illustrated the biological activity of C3 epimeric metabolites using an in vitro model, but the studies on in vivo models are substantially inadequate. The metabolic stability of 3-epi-1α,25(OH)2D3 has been demonstrated to be higher than its primary metabolites. 3-epi-1 alpha, 25 dihydroxyvitamin D3 (3-epi-1α,25(OH)2D3) is thought to have fewer calcemic effects than non-epimeric forms of vitamin D. Some researchers have observed a larger proportion of total vitamin D as C3-epimers in infants than in adults. Insufficient levels of vitamin D were found in mothers and their newborns when the epimers were not included in the measurement of vitamin D. Oral supplementation of vitamin D has also been found to potentially cause increased production of epimers in mice but not humans. Moreover, routine vitamin D blood tests for healthy adults will not be significantly affected by epimeric interference using LC-MS/MS assays. Recent genetic models also show that the genetic determinants and the potential factors of C3-epimers differ from those of non-C3-epimers.Most commercial immunoassays techniques can lead to inaccurate vitamin D results due to epimeric interference, especially in infants and pregnant women. It is also known that the LC-MS/MS technique can chromatographically separate epimeric and isobaric interference and detect vitamin D metabolites sensitively and accurately. Unfortunately, many labs around the world do not take into account the interference caused by epimers. In this review, various methods and techniques for the analysis of C3-epimers are also discussed. The authors believe that C3-epimers may have an important role to play in clinical research, and further research is warranted.
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Affiliation(s)
- Bashar Al-Zohily
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain 15551, UAE;
| | - Asma Al-Menhali
- Department of Biology, College of Science, United Arab Emirates University, Al Ain 15551, UAE
- Correspondence: (A.A.-M.); (I.S.)
| | - Salah Gariballa
- Internal Medicine, Faculty of Medicine & Health Sciences, United Arab Emirates University, Al Ain 15551, UAE;
| | - Afrozul Haq
- Department of Food Technology, School of Interdisciplinary Sciences and Technology, Jamia Hamdard University, New Delhi-110062, India;
| | - Iltaf Shah
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain 15551, UAE;
- Correspondence: (A.A.-M.); (I.S.)
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Kawagoe F, Yasuda K, Mototani S, Sugiyama T, Uesugi M, Sakaki T, Kittaka A. Synthesis and CYP24A1-Dependent Metabolism of 23-Fluorinated Vitamin D 3 Analogues. ACS OMEGA 2019; 4:11332-11337. [PMID: 31460236 PMCID: PMC6648426 DOI: 10.1021/acsomega.9b01500] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Two novel 23-fluorinated 25-hydroxyvitamin D3 analogues were synthesized using Inhoffen-Lythgoe diol as a precursor of the CD-ring, efficiently. Introduction of the C23 fluoro group was achieved by the deoxy-fluorination reaction using N,N-diethylaminosulfur trifluoride or 2-pyridinesulfonyl fluoride (PyFluor). Kinetic studies on the CYP24A1-dependent metabolism of these two analogues revealed that (23S)-23-fluoro-25-hydroxyvitamin D3 was more resistant to CYP24A1-dependent metabolism than its 23R isomer.
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Affiliation(s)
- Fumihiro Kawagoe
- Faculty
of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
- AMED-CREST, The
Japan Agency for Medical Research and Development
(AMED), Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Kaori Yasuda
- Faculty
of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Sayuri Mototani
- Faculty
of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Toru Sugiyama
- Faculty
of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Motonari Uesugi
- AMED-CREST, The
Japan Agency for Medical Research and Development
(AMED), Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
- Institute
for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Toshiyuki Sakaki
- Faculty
of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Atsushi Kittaka
- Faculty
of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
- AMED-CREST, The
Japan Agency for Medical Research and Development
(AMED), Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
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11
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Rendic SP, Peter Guengerich F. Human cytochrome P450 enzymes 5-51 as targets of drugs and natural and environmental compounds: mechanisms, induction, and inhibition - toxic effects and benefits. Drug Metab Rev 2019; 50:256-342. [PMID: 30717606 DOI: 10.1080/03602532.2018.1483401] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cytochrome P450 (P450, CYP) enzymes have long been of interest due to their roles in the metabolism of drugs, pesticides, pro-carcinogens, and other xenobiotic chemicals. They have also been of interest due to their very critical roles in the biosynthesis and metabolism of steroids, vitamins, and certain eicosanoids. This review covers the 22 (of the total of 57) human P450s in Families 5-51 and their substrate selectivity. Furthermore, included is information and references regarding inducibility, inhibition, and (in some cases) stimulation by chemicals. We update and discuss important aspects of each of these 22 P450s and questions that remain open.
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Affiliation(s)
| | - F Peter Guengerich
- b Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , TN , USA
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12
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Tuckey RC, Tang EKY, Maresse SR, Delaney DS. Catalytic properties of 25-hydroxyvitamin D3 3-epimerase in rat and human liver microsomes. Arch Biochem Biophys 2019; 666:16-21. [PMID: 30926433 DOI: 10.1016/j.abb.2019.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/26/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
25-Hydroxyvitamin D3 3-epimerase catalyzes the 3β → 3α epimerization of 25-hydroxyvitamin D3 (25(OH)D3) producing 3-epi-25-hydroxyvitamin D3 (3-epi-25(OH)D3). 3-Epi-25(OH)D3 is one of the most abundant forms of vitamin D present in the serum. It can be converted to 3-epi-1α,25-dihydroxyvitamin D3 by CYP27B1 which generally displays lower biological activity than 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). The 25(OH)D3 3-epimerase has been poorly characterized to date and the gene encoding it has not been identified. The 3-epimerase has been reported to be present in the microsomal fraction of cells, including liver cells, and to use NADPH as cofactor. It can also act on 1,25(OH)2D3 and 24,25(OH)2D3 forming the 3α-epimers. In this study we have characterized the activity of the 25(OH)D3 3-epimerase in rat and human liver microsomes, using 25(OH)D3 as substrate and HPLC to analyze product formation. For both rat and human liver microsomes the preferred cofactor was NADH, with the rat enzyme displaying a 6-fold greater catalytic efficiency (Vmax/Km) for NADH over that for NADPH. No activity was observed with oxidized cofactor, either NAD+ or NADP+. This was unexpected since the initial step in the epimerization, predicted to be the oxidation of the 3β-OH to a ketone, would require oxidized cofactor. The rat 3-epimerase in microsomes gave a Km for 25(OH)D3 of 14 μM. The reverse reaction, conversion of 3-epi-25(OH)D3 to 25(OH)D3, was catalyzed by both rat and human liver microsomes but at lower rates than the forward reaction. In conclusion, both rat and human 25-hydroxyvitamin D3 3-epimerase catalyze the reversible interconversion of 25(OH)D3 and 3-epi-25(OH)D3, and use NADH as the preferred cofactor. The lack of requirement for exogenous NAD+ suggests that the enzyme has a tightly bound NAD+ in its active site that is released only upon its reduction.
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Affiliation(s)
- Robert C Tuckey
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia.
| | - Edith K Y Tang
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Stephanie R Maresse
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Derek S Delaney
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
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13
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Tuckey RC, Cheng CYS, Slominski AT. The serum vitamin D metabolome: What we know and what is still to discover. J Steroid Biochem Mol Biol 2019; 186:4-21. [PMID: 30205156 PMCID: PMC6342654 DOI: 10.1016/j.jsbmb.2018.09.003] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 09/04/2018] [Accepted: 09/04/2018] [Indexed: 01/08/2023]
Abstract
Vitamin D, referring to the two forms, D2 from the diet and D3 primarily derived from phototransformation in the skin, is a prohormone important in human health. The most hormonally active form, 1α,25-dihydroxyvitamin D (1α,25(OH)2D), formed from vitamin D via 25-hydroxyvitamin D (25(OH)D), is not only important for regulating calcium metabolism, but has many pleiotropic effects including regulation of the immune system and has anti-cancer properties. The major circulating form of vitamin D is 25(OH)D and both D2 and D3 forms are routinely measured by LC/MS/MS to assess vitamin D status, due to their relatively long half-lives and much higher concentrations compared to 1α,25(OH)2D. Inactivation of both 25(OH)D and 1α,25(OH)2D is catalyzed by CYP24A1 and 25-hydroxyvitamin D3 3-epimerase. Initial products from these enzymes acting on 25(OH)D3 are 24R,25(OH)2D3 and 3-epi-25(OH)D3, respectively, and both of these can also be measured routinely in some clinical laboratories to further document vitamin D status. With advances in LC/MS/MS and its increased availability, and with the help of studies with recombinant vitamin D-metabolizing enzymes, many other vitamin D metabolites have now been detected and in some cases quantitated, in human serum. CYP11A1 which catalyzes the first step in steroidogenesis, has been found to also act on vitamins D3 and D2 hydroxylating both at C20, but with some secondary metabolites produced by subsequent hydroxylations at other positions on the side chain. The major vitamin D3 metabolite, 20S-hydroxyvitamin D3 (20S(OH)D3), shows biological activity, often similar to 1α,25(OH)2D3 but without calcemic effects. Using standards produced enzymatically by purified CYP11A1 and characterized by NMR, many of these new metabolites have been detected in human serum, with semi-quantitative measurement of 20S(OH)D3 indicating it is present at comparable concentrations to 24R,25(OH)2D3 and 3-epi-25(OH)D3. Recently, vitamin D-related hydroxylumisterols derived from lumisterol3, a previtamin D3 photoproduct, have also been measured in human serum and displayed biological activity in initial in vitro studies. With the current extensive knowledge on the reactions and pathways of metabolism of vitamin D, especially those catalyzed by CYP24A1, CYP27A1, CYP27B1, CYP3A4 and CYP11A1, it is likely that many other of the resulting hydroxyvitamin D metabolites will be measured in human serum in the future, some contributing to a more detailed understanding of vitamin D status in health and disease.
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Affiliation(s)
- Robert C Tuckey
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia.
| | - Chloe Y S Cheng
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Andrzej T Slominski
- Department of Dermatology, University of Alabama at Birmingham, AL, 35294, USA; Comprehensive Cancer Center Cancer Chemoprevention Program, University of Alabama at Birmingham, AL, 35294, USA; VA Medical Center, Birmingham, AL, 35294, USA
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14
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Yasuda K, Tohyama E, Takano M, Kittaka A, Ohta M, Ikushiro S, Sakaki T. Metabolism of 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D 3 by CYP24A1 and biological activity of its 24R-hydroxylated metabolite. J Steroid Biochem Mol Biol 2018; 178:333-339. [PMID: 29425808 DOI: 10.1016/j.jsbmb.2018.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 12/29/2022]
Abstract
Our previous study revealed that the 2α-substituted vitamin D analog 2α-[2-(tetrazol-2-yl)ethyl]-1α,25(OH)2D3 (AH-1) exhibited a higher osteocalcin promoter transactivation activity in human osteosarcoma cells and a greater effect on bone mineral density in a rat model of osteoporosis than 1α,25(OH)2D3 without increasing blood calcium concentration. Thus, we hypothesized that AH-1 could be a promising therapeutic agent for osteoporosis without any serious side effects. In this study, we compared the CYP24A1-dependent metabolism of AH-1 with that of 1α,25(OH)2D3. The resistance to CYP24A1-dependent metabolism could be an important property of vitamin D analogs in prolonging their biological effects. A kinetic analysis was performed using a membrane fraction prepared from recombinant E. coli expressing human CYP24A1. The kcat/Km (μM-1 min-1) value for AH-1 was 31% of that for 1α,25(OH)2D3, suggesting that AH-1 is not as resistant to CYP24A1-dependent metabolism as the other C2-substituted vitamin D analogs such as eldecalcitol [2β-hydroxypropoxy-1α,25(OH)2D3]. The major metabolite of AH-1 was the 24R-hydroxylated metabolite, which had high vitamin D receptor (VDR) binding affinity and high HL-60 cell differentiation activity similar to AH-1 itself. In contrast, 1α,25(OH)2D3 was metabolized by multistep monooxygenation reactions, which led to the loss of affinity for VDR. Thus, the greater therapeutic effects of AH-1 than those of 1α,25(OH)2D3 in in vivo studies using osteoporosis rat models may be due to 24R-hydroxy-AH-1 whose VDR affinity was 91% of that of AH-1.
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Affiliation(s)
- Kaori Yasuda
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan; Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Eri Tohyama
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo 173-8605, Japan
| | - Miho Ohta
- Development Nourishment Department, Soai University, 4-4-1 Nankonaka, Suminoe, Osaka 559-0033, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Toshiyuki Sakaki
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan; Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
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15
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Takano M, Yasuda K, Tohyama E, Higuchi E, Sakaki T, Kittaka A. Synthesis of the CYP24A1 major metabolite of 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D 3. J Steroid Biochem Mol Biol 2017; 173:75-78. [PMID: 27923594 DOI: 10.1016/j.jsbmb.2016.11.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 11/01/2016] [Accepted: 11/30/2016] [Indexed: 11/25/2022]
Abstract
Previously, we found that 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 (AH-1) showed higher osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells and a greater therapeutic effect on ovariectomized (OVX) rats for enhancing bone mineral density than those of 1α,25(OH)2D3 without hypercalcemic side effects in vivo. Although CYP24A1 catalyzes multi-step oxidations toward the CD-ring side chain of the active vitamin D3 [1α,25(OH)2D3], the CYP24A1-dependent metabolism of AH-1 tended to stop at the first step hydroxylation at the C24-position of AH-1. Interestingly, the metabolite 24-hydroxy-AH-1 [24(OH)AH-1] showed potent VDR binding affinity, and the new chiral center of the 24-position might be the 24R configuration compared with the process of the natural 1α,25(OH)2D3 catabolism. This time, (24R)-2α-[2-(tetrazol-2-yl)ethyl]-1α,24,25-trihydroxyvitamin D3 [(24R-OH)AH-1] was synthesized as a candidate for the major metabolite of AH-1 using the Trost Pd-mediated coupling reaction between A-ring and CD-ring precursors to identify the metabolite and evaluate its biological activity. We confirmed that the CYP24A1-dependent major metabolite of AH-1 was (24R-OH)AH-1 by HPLC analyses.
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Affiliation(s)
- Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Eri Tohyama
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Erika Higuchi
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Toshiyuki Sakaki
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan.
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan.
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16
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Takano M, Yasuda K, Higuchi E, Tohyama E, Takeuchi A, Sakaki T, Kittaka A. Synthesis, metabolism, and biological activity of 2-[3-(tetrazolyl)propyl]-1α,25-dihydroxy-19-norvitamin D 3. J Steroid Biochem Mol Biol 2016; 164:40-44. [PMID: 26232635 DOI: 10.1016/j.jsbmb.2015.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/22/2015] [Accepted: 07/27/2015] [Indexed: 11/20/2022]
Abstract
Recently, we found that 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 showed higher osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells and a greater therapeutic effect in ovariectomized (OVX) rats in vivo than those of active vitamin D3, 1α,25(OH)2D3. We were interested in introducing a heterocyclic ring to the C2 position of the seco-steroidal structure via an alkyl linker, and four novel C2-(3-tetrazolylpropyl) substituted 1α,25-dihydroxy-19-norvitamin D3 analogs, 2α-[3-(tetrazol-1-yl)propyl]-, 2β-[3-(tetrazol-1-yl)propyl]-, 2α-[3-(tetrazol-2-yl)propyl]-, and 2β-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 were synthesized. Among them, 2α-[3-(tetrazol-1-yl)propyl]-19-nor-1α,25(OH)2D3 showed weak binding affinity for human vitamin D receptor (hVDR) (2.6% of 1α,25(OH)2D3 and ca. 15% of 19-nor-1α,25(OH)2D3) and weak VDR transactivation activity in HOS cells (EC50 7.3nM, when 1α,25(OH)2D30.23nM). Although the other three compounds could not act as VDR binders by evaluation of the competition assays, 2α-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 showed weak transactivation activity (EC50 12.5nM). Metabolic stability of the 2α-substituted compounds 2α-[3-(tetrazol-1-yl)propyl]- and 2α-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 was higher than that of the 2β-substituted counterparts 2β-[3-(tetrazol-1-yl)propyl]- and 2β-[3-(tetrazol-2-yl)propyl]-19-nor-1α,25(OH)2D3 against human CYP24A1. Introduction of a tetrazole ring to the C2-position of the 19-norvitamin D3 skeleton with the propyl linker led to weak VDR agonistic activity with stability against CYP24A1 metabolism.
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Affiliation(s)
- Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Erika Higuchi
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Eri Tohyama
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Akiko Takeuchi
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Toshiyuki Sakaki
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan.
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17
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Bolla NR, Corcoran A, Yasuda K, Chodyński M, Krajewski K, Cmoch P, Marcinkowska E, Brown G, Sakaki T, Kutner A. Synthesis and evaluation of geometric analogs of 1α,25-dihydroxyvitamin D 2 as potential therapeutics. J Steroid Biochem Mol Biol 2016; 164:50-55. [PMID: 26321387 DOI: 10.1016/j.jsbmb.2015.08.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 02/06/2023]
Abstract
An improved convergent strategy was developed for the synthesis of the previously obtained side-chain extended and rigidified analogs of 1α,25-dihydroxyvitamin D2, PRI-1906 and PRI-1907. New (24Z) geometric isomers of the analogs, PRI-1916 and PRI-1917, were also obtained and identified. These side-chain isomers were separable by flash chromatography, as C-25 alcohols, from the synthetic precursors of PRI-1906 and PRI-1907, respectively. The structures of new analogs were determined by advanced techniques of 1H and 13C NMR, including COSY, HSQC and HMBC sequences. Binding affinities of the geometric analogs PRI-1906 and PRI-1916 and their respective C-26, C-27 homologs PRI-1907 and PRI-1917 for the full-length human vitamin D receptor were determined by a fluorescence polarization competition assay. The binding affinity of (24Z) methyl analog PRI-1906 was much higher than that of (24E) analog PRI-1906, while the affinity of (24Z) ethyl analog PRI-1917 was lower than that of the respective PRI-1907. Investigation of the metabolism of these compounds by human CYP24A1 revealed they are much more resistant to CYP24A1 than 1α,25-dihydroxyvitamin D2, indicating they could have longer-term biological effects on target tissues.
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Affiliation(s)
| | - Aoife Corcoran
- Faculty of Biotechnology, University of Wroclaw, 14a Joliot-Curie, 50-383 Wroclaw, Poland
| | - Kaori Yasuda
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Michał Chodyński
- Pharmaceutical Research Institute, 8 Rydygiera, 01-793 Warsaw, Poland
| | | | - Piotr Cmoch
- Pharmaceutical Research Institute, 8 Rydygiera, 01-793 Warsaw, Poland
| | - Ewa Marcinkowska
- Faculty of Biotechnology, University of Wroclaw, 14a Joliot-Curie, 50-383 Wroclaw, Poland
| | - Geoffrey Brown
- School of Immunity and Infection, University of Birmingham, Vincent Drive, Edgbaston, Birmingham, West Midlands B15 2TT, UK
| | - Toshiyuki Sakaki
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Andrzej Kutner
- Pharmaceutical Research Institute, 8 Rydygiera, 01-793 Warsaw, Poland
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18
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Gahl WA, Mulvihill JJ, Toro C, Markello TC, Wise AL, Ramoni RB, Adams DR, Tifft CJ. The NIH Undiagnosed Diseases Program and Network: Applications to modern medicine. Mol Genet Metab 2016; 117:393-400. [PMID: 26846157 PMCID: PMC5560125 DOI: 10.1016/j.ymgme.2016.01.007] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The inability of some seriously and chronically ill individuals to receive a definitive diagnosis represents an unmet medical need. In 2008, the NIH Undiagnosed Diseases Program (UDP) was established to provide answers to patients with mysterious conditions that long eluded diagnosis and to advance medical knowledge. Patients admitted to the NIH UDP undergo a five-day hospitalization, facilitating highly collaborative clinical evaluations and a detailed, standardized documentation of the individual's phenotype. Bedside and bench investigations are tightly coupled. Genetic studies include commercially available testing, single nucleotide polymorphism microarray analysis, and family exomic sequencing studies. Selected gene variants are evaluated by collaborators using informatics, in vitro cell studies, and functional assays in model systems (fly, zebrafish, worm, or mouse). INSIGHTS FROM THE UDP In seven years, the UDP received 2954 complete applications and evaluated 863 individuals. Nine vignettes (two unpublished) illustrate the relevance of an undiagnosed diseases program to complex and common disorders, the coincidence of multiple rare single gene disorders in individual patients, newly recognized mechanisms of disease, and the application of precision medicine to patient care. CONCLUSIONS The UDP provides examples of the benefits expected to accrue with the recent launch of a national Undiagnosed Diseases Network (UDN). The UDN should accelerate rare disease diagnosis and new disease discovery, enhance the likelihood of diagnosing known diseases in patients with uncommon phenotypes, improve management strategies, and advance medical research.
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Affiliation(s)
- William A Gahl
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - John J Mulvihill
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Department of Pediatrics, University of Oklahoma, Oklahoma City, OK, United States.
| | - Camilo Toro
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Thomas C Markello
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Anastasia L Wise
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Rachel B Ramoni
- Department for Biomedical Informatics, Harvard Medical School, Department of Oral Health Policy and Epidemiology, Harvard Dental School, Cambridge, MA, United States
| | - David R Adams
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Cynthia J Tifft
- NIH Undiagnosed Diseases Network, Common Fund, Office of the Director and the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
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Biological Evaluation of Double Point Modified Analogues of 1,25-Dihydroxyvitamin D₂ as Potential Anti-Leukemic Agents. Int J Mol Sci 2016; 17:ijms17020091. [PMID: 26840307 PMCID: PMC4783874 DOI: 10.3390/ijms17020091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 12/29/2015] [Accepted: 01/04/2016] [Indexed: 02/05/2023] Open
Abstract
Structurally similar double-point modified analogues of 1,25-dihydroxyvitamin D2 (1,25D2) were screened in vitro for their pro-differentiating activity against the promyeloid cell line HL60. Their affinities towards human full length vitamin D receptor (VDR) and metabolic stability against human vitamin D 24-hydroxylase (CYP24A1) were also tested. The analogues (PRI-1730, PRI-1731, PRI-1732, PRI-1733 and PRI-1734) contained 5,6-trans modification of the A-ring and of the triene system, additional hydroxyl or unsaturation at C-22 in the side chain and reversed absolute configuration (24-epi) at C-24 of 1,25D2. As presented in this paper, introduction of selected structural modifications simultaneously in two distinct parts of the vitamin D molecule resulted in a divergent group of analogues. Analogues showed lower VDR affinity in comparison to that of the parent hormones, 1,25D2 and 1,25D3, and they caused effective HL60 cell differentiation only at high concentrations of 100 nM and above. Unexpectedly, introducing of a 5,6-trans modification combined with C-22 hydroxyl and 24-epi configuration switched off entirely the cell differentiation activity of the analogue (PRI-1734). However, this analogue remained a moderate substrate for CYP24A1, as it was metabolized at 22%, compared to 35% for 1,25D2. Other analogues from this series were either less (12% for PRI-1731 and PRI-1733) or more (52% for PRI-1732) resistant to the enzymatic deactivation. Although the inactive analogue PRI-1734 failed to show VDR antagonism, when tested in HL60 cells, its structure might be a good starting point for our design of a vitamin D antagonist.
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Yasuda K, Iwanaga Y, Ogawa K, Mano H, Ueno S, Kimoto S, Ohta M, Kamakura M, Ikushiro S, Sakaki T. Human hepatic metabolism of the anti-osteoporosis drug eldecalcitol involves sterol C4-methyl oxidase. Pharmacol Res Perspect 2015; 3:e00120. [PMID: 26038696 PMCID: PMC4448988 DOI: 10.1002/prp2.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 11/28/2014] [Accepted: 11/30/2014] [Indexed: 11/22/2022] Open
Abstract
The metabolism of eldecalcitol (ED-71), a 2β-hydroxypropoxylated analog of the active form of vitamin D3 was investigated by using in vitro systems. ED-71 was metabolized to 1α,2β,25-trihydroxyvitamin D3 (1α,2β,25(OH)3D3) in human small intestine and liver microsomes. To identify the enzymes involved in this metabolism, we examined NADPH-dependent metabolism by recombinant P450 isoforms belonging to the CYP1, 2, and 3 families, and revealed that CYP3A4 had the activity. However, the CYP3A4 -specific inhibitor, ketoconazole, decreased the activity in human liver microsomes by only 36%, suggesting that other enzymes could be involved in ED-71 metabolism. Because metabolism was dramatically inhibited by cyanide, we assumed that sterol C4-methyl oxidase like gene product (SC4MOL) might contribute to the metabolism of ED-71. It is noted that SC4MOL is physiologically essential for cholesterol synthesis. Recombinant human SC4MOL expressed in COS7, Saccharomyces cerevisiae, or Escherichia coli cells converted ED-71 to 1α,2β,25(OH)3D3. Furthermore, we evaluated the metabolism of ED-71 by recombinant CYP24A1, which plays an important role in the metabolism of the active form of vitamin D3 (1α,25(OH)2D3) and its analogs. The kcat/Km value for 24- or 23-hydroxylation of ED-71 was only 3% of that for 1α,25(OH)2D3, indicating that ED-71 was resistant to CYP24A1-dependent catabolism. Among the three enzymes catalyzing ED-71, SC4MOL appears to be most important in the metabolism of ED-71. To the best of our knowledge, this is the first study showing that SC4MOL can function as a drug-metabolizing enzyme. The yeast and E. coli expression systems for SC4MOL could be useful for structure-function analyses of SC4MOL.
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Affiliation(s)
- Kaori Yasuda
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Yuasa Iwanaga
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Kazuaki Ogawa
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Hiroki Mano
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Sera Ueno
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Shutaro Kimoto
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Miho Ohta
- Development Nourishment Department, Soai University 4-4-1 Nankonaka, Suminoe, Osaka, 559-0033, Japan
| | - Masaki Kamakura
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Shinichi Ikushiro
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
| | - Toshiyuki Sakaki
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan
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Tieu EW, Li W, Chen J, Kim TK, Ma D, Slominski AT, Tuckey RC. Metabolism of 20-hydroxyvitamin D3 and 20,23-dihydroxyvitamin D3 by rat and human CYP24A1. J Steroid Biochem Mol Biol 2015; 149:153-65. [PMID: 25727742 PMCID: PMC4380815 DOI: 10.1016/j.jsbmb.2015.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/15/2015] [Accepted: 02/16/2015] [Indexed: 11/19/2022]
Abstract
CYP11A1 hydroxylates vitamin D3 producing 20S-hydroxyvitamin D3 [20(OH)D3] and 20S,23-dihydroxyvitamin D3 [20,23(OH)2D3] as the major and most characterized metabolites. Both display immuno-regulatory and anti-cancer properties while being non-calcemic. A previous study indicated 20(OH)D3 can be metabolized by rat CYP24A1 to products including 20S,24-dihydroxyvitamin D3 [20,24(OH)2D3] and 20S,25-dihydroxyvitamin D3, with both producing greater inhibition of melanoma colony formation than 20(OH)D3. The aim of this study was to characterize the ability of rat and human CYP24A1 to metabolize 20(OH)D3 and 20,23(OH)2D3. Both isoforms metabolized 20(OH)D3 to the same dihydroxyvitamin D species with no secondary metabolites being observed. Hydroxylation at C24 produced both enantiomers of 20,24(OH)2D3. For rat CYP24A1 the preferred initial site of hydroxylation was at C24 whereas the human enzyme preferred C25. 20,23(OH)2D3 was initially metabolized to 20S,23,24-trihydroxyvitamin D3 and 20S,23,25-trihydroxyvitamin D3 by rat and human CYP24A1 as determined by NMR, with both isoforms showing a preference for initial hydroxylation at C25. CYP24A1 was able to further oxidize these metabolites in a series of reactions which included the cleavage of C23-C24 bond, as indicated by high resolution mass spectrometry of the products, analogous to the catabolism of 1,25(OH)2D3 via the C24-oxidation pathway. Similar catalytic efficiencies were observed for the metabolism of 20(OH)D3 and 20,23(OH)2D3 by human CYP24A1 and were lower than for the metabolism of 1,25(OH)2D3. We conclude that rat and human CYP24A1 metabolizes 20(OH)D3 producing only dihydroxyvitamin D3 species as products which retain biological activity, whereas 20,23(OH)2D3 undergoes multiple oxidations which include cleavage of the side chain.
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Affiliation(s)
- Elaine W Tieu
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia
| | - Wei Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jianjun Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Pharmaceutical Sciences, School of Pharmacy, South College, Knoxville, TN, USA
| | - Tae-Kang Kim
- Department of Pathology and Laboratory Medicine, Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Dejian Ma
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Andrzej T Slominski
- Department of Pathology and Laboratory Medicine, Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Dermatology, University of Alabama Birmingham, Birmingham, AL, USA
| | - Robert C Tuckey
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia.
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22
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Takano M, Sawada D, Yasuda K, Nishikawa M, Takeuchi A, Takagi KI, Horie K, Reddy GS, Chen TC, Sakaki T, Kittaka A. Synthesis and metabolic studies of 1α,2α,25-, 1α,4α,25- and 1α,4β,25-trihydroxyvitamin D3. J Steroid Biochem Mol Biol 2015; 148:34-7. [PMID: 25263656 DOI: 10.1016/j.jsbmb.2014.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/17/2014] [Accepted: 09/22/2014] [Indexed: 11/24/2022]
Abstract
Three different A-ring perhydroxylated trihydroxyvitamin D3 metabolites were synthesized from their appropriate A-ring precursors and CD-ring for their potential therapeutic applications. We first chemically synthesized 1α,2α,25-trihydroxyvitamin D3 [1α,2α,25(OH)3D3] to study its VDR binding affinity because this metabolite is a product of recombinant human CYP3A4 catalysis when 2α-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D3 (O2C3), a more potent vitamin D receptor (VDR) binder than 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], is used as the substrate. We found that this metabolite retained 27.3% of the VDR binding affinity compared to 1α,25(OH)2D3. The kcat/Km value of CYP24A1 for 1α,2α,25(OH)3D3 is 60% of that for 1α,25(OH)2D3. Since the biological activity and the metabolic fate of a naturally occurring C4-hydroxylated vitamin D2 metabolite found in the serum of rats treated with pharmacological doses of vitamin D2 have never been described, we next synthesized 1α,4α,25-trihydroxyvitamin D3 and its diastereoisomer, 1α,4β,25-trihydroxyvitamin D3, to study their metabolism and biological activities. Both 4-hydroxylated isomers showed weaker VDR binding affinity than 1α,25(OH)2D3. Although either 4-hydroxylated isomer can be metabolized by CYP24A1 almost at the same level as 1α,25(OH)2D3, their metabolic patterns catalyzed by uridine 5'-diphosphoglucuronosyltransferase (UGT) are different; only the 4α-hydroxylated analog can be metabolized by UGT to produce a glucuronate conjugate. The results provide important information for the synthesis of new novel chemotherapeutic vitamin D analogs which would be less subjective to degradation and therefore more bioavailable than 1α,25(OH)2D3. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.
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Affiliation(s)
- Masashi Takano
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Daisuke Sawada
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Kaori Yasuda
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Miyu Nishikawa
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Akiko Takeuchi
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Ken-Ichiro Takagi
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | - Kyohei Horie
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd., Hino, Tokyo 191-8512, Japan
| | | | - Tai C Chen
- Section of Endocrinology, Diabetes & Nutrition, Boston University School of Medicine, Boston, MA 02118, USA
| | - Toshiyuki Sakaki
- Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama 939-0398, Japan
| | - Atsushi Kittaka
- Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan.
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Tieu EW, Tang EKY, Tuckey RC. Kinetic analysis of human CYP24A1 metabolism of vitamin D via the C24-oxidation pathway. FEBS J 2014; 281:3280-96. [PMID: 24893882 DOI: 10.1111/febs.12862] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 05/14/2014] [Accepted: 05/30/2014] [Indexed: 11/30/2022]
Abstract
CYP24A1 is the multicatalytic cytochrome P450 responsible for the catabolism of vitamin D via the C23- and C24-oxidation pathways. We successfully expressed the labile human enzyme in Escherichia coli and partially purified it in an active state that permitted detailed characterization of its metabolism of 1,25-dihydroxyvitamin D3 [1,25(OH)2 D3] and the intermediates of the C24-oxidation pathway in a phospholipid-vesicle reconstituted system. The C24-oxidation pathway intermediates, 1,24,25-trihydroxyvitamin D3, 24-oxo-1,25-dihydroxyvitamin D3, 24-oxo-1,23,25-trihydroxyvitamin D3 and tetranor-1,23-dihydroxyvitamin D3, were enzymatically produced from 1,25(OH)2 D3 using rat CYP24A1. Both 1,25(OH)2 D3 and 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3 were found to partition strongly into the phospholipid bilayer when in aqueous medium. Changes to the phospholipid concentration did not affect the kinetic parameters for the metabolism of 1,25(OH)2 D3 by CYP24A1, indicating that it is the concentration of substrates in the membrane phase (mol substrate·mol phospholipid(-1) ) that determines their rate of metabolism. CYP24A1 exhibited Km values for the different C24-intermediates ranging from 0.34 to 15 mmol·mol phospholipid(-1) , with 24-oxo-1,23,25-trihydroxyvitamin D3 [24-oxo-1,23,25(OH)3 D3] displaying the lowest and 1,24,25-trihydroxyvitamin D3 [1,24,25(OH)3 D3] displaying the highest. The kcat values varied by up to 3.8-fold, with 1,24,25(OH)3 D3 displaying the highest kcat (34 min(-1) ) and 24-oxo-1,23,25(OH)3 D3 the lowest. The data show that the cleavage of the side chain of 24-oxo-1,23,25(OH)3 D3 occurs with the highest catalytic efficiency (kcat /Km ) and produces 1-hydroxy-23-oxo-24,25,26,27-tetranorvitamin D3 and not 1,23-dihydroxy-24,25,26,27-tetranorvitamin D3, as the primary product. These kinetic analyses also show that intermediates of the C24-oxidation pathway effectively compete with precursor substrates for binding to the active site of the enzyme, which manifests as an accumulation of intermediates, indicating that they dissociate after each catalytic step.
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Affiliation(s)
- Elaine W Tieu
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Australia
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24
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Rhieu SY, Annalora AJ, Wang G, Flarakos CC, Gathungu RM, Vouros P, Sigüeiro R, Mouriño A, Schuster I, Palmore GTR, Reddy GS. Metabolic stability of 3-Epi-1α,25-dihydroxyvitamin D3over 1α, 25-dihydroxyvitamin D3: Metabolism and molecular docking studies using rat CYP24A1. J Cell Biochem 2013; 114:2293-305. [DOI: 10.1002/jcb.24576] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/12/2013] [Indexed: 11/08/2022]
Affiliation(s)
| | - Andrew J. Annalora
- Department of Molecular Biology; The Scripps Research Institute; La Jolla; California; 92037
| | | | - Caroline C. Flarakos
- Department of Chemistry and Chemical Biology; Northeastern University; Boston; Massachusetts; 02115
| | - Rose M. Gathungu
- Department of Chemistry and Chemical Biology; Northeastern University; Boston; Massachusetts; 02115
| | - Paul Vouros
- Department of Chemistry and Chemical Biology; Northeastern University; Boston; Massachusetts; 02115
| | - Rita Sigüeiro
- Departamento de Química Orgánica, Laboratorio de Investigación Ignacio Ribas; Universidad de Santiago de Compostela; E-15706; Santiago de Compostela; Spain
| | - Antonio Mouriño
- Departamento de Química Orgánica, Laboratorio de Investigación Ignacio Ribas; Universidad de Santiago de Compostela; E-15706; Santiago de Compostela; Spain
| | - Inge Schuster
- Institute for Theoretical Chemistry; University of Vienna; Vienna; Austria
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25
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Nesterova G, Malicdan MC, Yasuda K, Sakaki T, Vilboux T, Ciccone C, Horst R, Huang Y, Golas G, Introne W, Huizing M, Adams D, Boerkoel CF, Collins MT, Gahl WA. 1,25-(OH)2D-24 Hydroxylase (CYP24A1) Deficiency as a Cause of Nephrolithiasis. Clin J Am Soc Nephrol 2013; 8:649-57. [PMID: 23293122 DOI: 10.2215/cjn.05360512] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND OBJECTIVES Elevated serum vitamin D with hypercalciuria can result in nephrocalcinosis and nephrolithiasis. This study evaluated the cause of excess 1,25-dihydroxycholecalciferol (1α,25(OH)2D3) in the development of those disorders in two individuals. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Two patients with elevated vitamin D levels and nephrocalcinosis or nephrolithiasis were investigated at the National Institutes of Health (NIH) Clinical Center and the NIH Undiagnosed Diseases Program, by measuring calcium, phosphate, and vitamin D metabolites, and by performing CYP24A1 mutation analysis. RESULTS Both patients exhibited hypercalciuria, hypercalcemia, low parathyroid hormone, elevated vitamin D (1α,25(OH)2D3), normal 25-OHD3, decreased 24,25(OH)2D, and undetectable activity of 1,25(OH)2D-24-hydroxylase (CYP24A1), the enzyme that inactivates 1α,25(OH)2D3. Both patients had bi-allelic mutations in CYP24A1 leading to loss of function of this enzyme. On the basis of dbSNP data, the frequency of predicted deleterious bi-allelic CYP24A1 variants in the general population is estimated to be as high as 4%-20%. CONCLUSIONS The results of this study show that 1,25(OH)2D-24-hydroxylase deficiency due to bi-allelic mutations in CYP24A1 causes elevated serum vitamin D, hypercalciuria, nephrocalcinosis, and renal stones.
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Affiliation(s)
- Galina Nesterova
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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26
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Yasuda K, Ikushiro S, Kamakura M, Takano M, Saito N, Kittaka A, Chen TC, Ohta M, Sakaki T. Human cytochrome P450-dependent differential metabolism among three 2α-substituted-1α,25-dihydroxyvitamin D(3) analogs. J Steroid Biochem Mol Biol 2013; 133:84-92. [PMID: 22982757 DOI: 10.1016/j.jsbmb.2012.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 09/05/2012] [Accepted: 09/07/2012] [Indexed: 11/27/2022]
Abstract
Our previous studies revealed that C2α-substituted-1α,25(OH)(2)D(3) analogs had unique biological activities. For example, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (MART-10), which has a high affinity for vitamin D receptor (VDR), is more bioavailable and more potent than 1α,25(OH)(2)D(3) in inhibiting cancer cell growth and invasion because of its weaker binding to vitamin D binding protein (DBP), and more resistance to CYP24A1-dependent metabolism. In this study, we examined the metabolism of MART-10 and two other 2α-substituted analogs, 2α-(3-hydroxypropoxy)-1α,25(OH)(2)D(3) (O2C3) and 2α-(3-hydroxypropyl)-1α,25(OH)(2)D(3) (O1C3) by using human liver microsomes and human P450s. We demonstrated that O2C3 was converted to 1α,2α,25(OH)(3)D(3) in human liver microsomes, whereas both O1C3 and MART-10 were hardly metabolized. The metabolism of O2C3 was significantly inhibited by ketoconazole, and the recombinant human CYP3A4 converted O2C3 to 1α,2α,25(OH)(3)D(3), which suggests that CYP3A4 is responsible for the metabolism of O2C3 in human liver. The k(cat)/K(m) values of CYP3A4 for O1C3 and MART-10 are much smaller than that for O2C3. The k(cat)/K(m) values of human CYP24A1 for the three analogs are 1% (MART-10), 3% (O2C3), and 4% (O1C3) of that for 1α,25(OH)(2)D(3), indicating that MART-10 is the most resistant to CYP24A1 hydroxylation. On the other hand, 1α,2α,25(OH)(3)D(3), the metabolite of O2C3 by CYP3A4, was metabolized by CYP24A1 via multiple pathways similar to 1α,25(OH)(2)D(3), which suggests that O2C3 can be metabolized by two sequential hydroxylations, first by CYP3A4 and then by CYP24A1 in human body. These results suggest that modification at C-2α position and C-19 demethylenation markedly change metabolic profiles and biological activities of vitamin D analogs.
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Affiliation(s)
- Kaori Yasuda
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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27
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Gathungu RM, Flarakos CC, Reddy GS, Vouros P. The role of mass spectrometry in the analysis of vitamin D compounds. MASS SPECTROMETRY REVIEWS 2013; 32:72-86. [PMID: 22996283 DOI: 10.1002/mas.21353] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/03/2012] [Accepted: 04/03/2012] [Indexed: 06/01/2023]
Abstract
This review highlights the superseding role of mass spectrometry in the structural characterization and quantitation of vitamin D compounds in comparison to other analytical methods (e.g., UV, bioassays) that lack the sensitivity and specificity of mass spectrometry. After a short introduction to the biochemistry of vitamin D compounds, an overview of the current techniques to characterize and quantitate vitamin D compounds is given with emphasis on the contribution of mass spectrometry.
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Affiliation(s)
- Rose M Gathungu
- Barnett Institute of Chemical and Biological Analysis, Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
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28
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Sawada D, Tsukuda Y, Yasuda K, Sakaki T, Saito H, Takagi KI, Takenouchi K, Chen TC, Reddy GS, Kittaka A. Synthesis and Biological Activities of 1α,4α,25- and 1α,4β,25-Trihydroxyvitamin D 3 and Their Metabolism by Human CYP24A1 and UDP-Glucuronosyltransferase. Chem Pharm Bull (Tokyo) 2012; 60:1343-6. [DOI: 10.1248/cpb.c12-00526] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Yuya Tsukuda
- Faculty of Pharmaceutical Sciences, Teikyo University
| | - Kaori Yasuda
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University
| | - Toshiyuki Sakaki
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University
| | - Hiroshi Saito
- Teijin Institute for Bio-medical Research, Teijin Pharma Ltd
| | | | | | - Tai C. Chen
- Section of Endocrinology, Diabetes and Nutrition, School of Medicine, Boston University
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29
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Rhieu SY, Annalora AJ, Gathungu RM, Vouros P, Uskokovic MR, Schuster I, Palmore GTR, Reddy GS. A new insight into the role of rat cytochrome P450 24A1 in metabolism of selective analogs of 1α,25-dihydroxyvitamin D₃. Arch Biochem Biophys 2011; 509:33-43. [PMID: 21338573 DOI: 10.1016/j.abb.2011.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 02/03/2011] [Accepted: 02/08/2011] [Indexed: 10/18/2022]
Abstract
We examined the metabolism of two synthetic analogs of 1α,25-dihydroxyvitamin D₃ (1), namely 1α,25-dihydroxy-16-ene-23-yne-vitamin D₃ (2) and 1α,25-dihydroxy-16-ene-23-yne-26,27-dimethyl-vitamin D₃ (4) using rat cytochrome P450 24A1 (CYP24A1) in a reconstituted system. We noted that 2 is metabolized into a single metabolite identified as C26-hydroxy-2 while 4 is metabolized into two metabolites, identified as C26-hydroxy-4 and C26a-hydroxy-4. The structural modification of adding methyl groups to the side chain of 1 as in 4 is also featured in another analog, 1α,25-dihydroxy-22,24-diene-24,26,27-trihomo-vitamin D₃ (6). In a previous study, 6 was shown to be metabolized exactly like 4, however, the enzyme responsible for its metabolism was found to be not CYP24A1. To gain a better insight into the structural determinants for substrate recognition of different analogs, we performed an in silico docking analysis using the crystal structure of rat CYP24A1 that had been solved for the substrate-free open form. Whereas analogs 2 and 4 docked similar to 1, 6 showed altered interactions for both the A-ring and side chain, despite prototypical recognition of the CD-ring. These findings hint that CYP24A1 metabolizes selectively different analogs of 1, based on their ability to generate discrete recognition cues required to close the enzyme and trigger the catalytic mechanism.
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30
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Kittaka A, Sakaki T, Hara H, Yasuda K, Takano M, A. Arai M, Sawada D, Saito H, Takenouchi K, C. Chen T. Studies on the Synthesis and Metabolism of 14-epi-2α-(3-Hydroxypropyl)-19-norvitamin D3 and Its 2β-Isomer. HETEROCYCLES 2010. [DOI: 10.3987/com-10-s(e)40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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Synthesis of 2α-propoxy-1α,25-dihydroxyvitamin D3 and comparison of its metabolism by human CYP24A1 and rat CYP24A1. Bioorg Med Chem 2009; 17:4296-301. [DOI: 10.1016/j.bmc.2009.05.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 05/11/2009] [Accepted: 05/12/2009] [Indexed: 11/19/2022]
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32
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Urushino N, Yasuda K, Ikushiro S, Kamakura M, Ohta M, Sakaki T. Metabolism of 1alpha,25-dihydroxyvitamin D2 by human CYP24A1. Biochem Biophys Res Commun 2009; 384:144-8. [PMID: 19393625 DOI: 10.1016/j.bbrc.2009.04.075] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
Abstract
The metabolism of 1alpha,25-dihydroxyvitamin D2 (1alpha,25(OH)2D2) by human CYP24A1 was examined using the recombinant enzyme expressed in Escherichia coli cells. HPLC analysis revealed that human CYP24A1 produces at least 10 metabolites, while rat CYP24A1 produces only three metabolites, indicating a remarkable species-based difference in the CYP24A1-dependent metabolism of 1alpha,25(OH)2D2 between humans and rats. LC-MS analysis and periodate treatment of the metabolites strongly suggest that human CYP24A1 converts 1alpha,25(OH)2D2 to 1alpha,24,25,26(OH)4D2, 1alpha,24,25,28(OH)4D2, and 24-oxo-25,26,27-trinor-1alpha(OH)D2 via 1alpha,24,25(OH)3D2. These results indicate that human CYP24A1 catalyzes the C24-C25 bond cleavage of 1alpha,24,25(OH)2D2, which is quite effective in the inactivation of the active form of vitamin D2. The combination of hydroxylation at multiple sites and C-C bond cleavage could form a large number of metabolites. Our findings appear to be useful to predict the metabolism of vitamin D2 and its analogs in the human body.
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Affiliation(s)
- Naoko Urushino
- Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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Urushino N, Nakabayashi S, Arai MA, Kittaka A, Chen TC, Yamamoto K, Hayashi K, Kato S, Ohta M, Kamakura M, Ikushiro S, Sakaki T. Kinetic Studies of 25-Hydroxy-19-nor-vitamin D3 and 1α,25-Dihydroxy-19-nor-vitamin D3 Hydroxylation by CYP27B1 and CYP24A1. Drug Metab Dispos 2007; 35:1482-8. [PMID: 17553915 DOI: 10.1124/dmd.107.015602] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our previous study demonstrated that 25-hydroxy-19-nor-vitamin D(3) [25(OH)-19-nor-D(3)] inhibited the proliferation of immortalized noncancerous PZ-HPV-7 prostate cells similar to 1 alpha,25-dihydroxyvitamin D(3) [1 alpha,25(OH)(2)D(3)], suggesting that 25(OH)-19-nor-D(3) might be converted to 1 alpha,25-dihydroxy-19-nor-vitamin D(3) [1 alpha,25(OH)(2)-19-nor-D(3)] by CYP27B1 before exerting its antiproliferative activity. Using an in vitro cell-free model to study the kinetics of CYP27B1-dependent 1 alpha-hydroxylation of 25(OH)-19-nor-D(3) and 25-hydroxyvitamin D(3) [25(OH)D(3)] and CYP24A1-dependent hydroxylation of 1 alpha,25(OH)-19-nor-D(3) and 1 alpha,25(OH)(2)D(3), we found that k(cat)/K(m) for 1 alpha-hydroxylation of 25(OH)-19-nor-D(3) was less than 0.1% of that for 25(OH)D(3), and the k(cat)/K(m) value for 24-hydroxylation was not significantly different between 1 alpha,25(OH)(2)-19-nor-D(3) and 1 alpha,25(OH)(2)D(3). The data suggest a much slower formation and a similar rate of degradation of 1 alpha,25(OH)(2)-19-nor-D(3) compared with 1 alpha,25(OH)(2)D(3). We then analyzed the metabolites of 25(OH)D(3) and 25(OH)-19-nor-D(3) in PZ-HPV-7 cells by high-performance liquid chromatography. We found that a peak that comigrated with 1 alpha,25(OH)(2)D(3) was detected in cells incubated with 25(OH)D(3), whereas no 1 alpha,25(OH)(2)-19-nor-D(3) was detected in cells incubated with 25(OH)-19-nor-D(3). Thus, the present results do not support our previous hypothesis that 25(OH)-19-nor-D(3) is converted to 1 alpha,25(OH)(2)-19-nor-D(3) by CYP27B1 in prostate cells to inhibit cell proliferation. We hypothesize that 25(OH)-19-nor-D(3) by itself may have a novel mechanism to activate vitamin D receptor or it is metabolized in prostate cells to an unknown metabolite with antiproliferative activity without 1 alpha-hydroxylation. Thus, the results suggest that 25(OH)-19-nor-D(3) has potential as an attractive agent for prostate cancer therapy.
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Affiliation(s)
- Naoko Urushino
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Oiwake-cho, Sakyo-ku, Kyoto, Japan
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Sawada N, Yamamoto K, Yamada S, Ikushiro S, Kamakura M, Ohta M, Inouye K, Sakaki T. Role of Gln 85 of human CYP27A1 in 25-hydroxyvitamin D(3)-binding and protein folding. Biochem Biophys Res Commun 2007; 355:211-6. [PMID: 17292862 DOI: 10.1016/j.bbrc.2007.01.158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 01/26/2007] [Indexed: 11/23/2022]
Abstract
CYP27A1 catalyzes vitamin D(3) 25-hydroxylation and further hydroxylation at C-1alpha, C-24 or C-26(27). Molecular modeling of human CYP27A1 and docking with 25-hydroxyvitamin D(3) predicted that Gln 85 might be important for 1alpha-hydroxylation activity of CYP27A1 by forming a hydrogen bond with the 25-OH group of 25-hydroxyvitamin D(3). Expectedly, the mutant Q85H expressed in Escherichia coli showed no detectable 1alpha-hydroxylation activity toward 25-hydroxyvitamin D(3). In addition, Q85H prefers 24-hydroxylation toward 25-hydroxyvitamin D(3) whereas the wild-type prefers 26(27)-hydroxylation. A molecular modeling study also suggests that Gln 85 of CYP27A1 simultaneously interacts with Asn 107 and the hydroxyl group of the substrate. The fact that Q85L did not contain a heme molecule suggests that the hydrogen bond between Gln 85 and Asn 107 is important for protein folding of CYP27A1. Based on these results, it is possible that Gln 85 plays essential roles in both substrate-binding and protein folding.
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Affiliation(s)
- Natsumi Sawada
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Hamamoto H, Kusudo T, Urushino N, Masuno H, Yamamoto K, Yamada S, Kamakura M, Ohta M, Inouye K, Sakaki T. Structure-function analysis of vitamin D 24-hydroxylase (CYP24A1) by site-directed mutagenesis: amino acid residues responsible for species-based difference of CYP24A1 between humans and rats. Mol Pharmacol 2006; 70:120-8. [PMID: 16617161 DOI: 10.1124/mol.106.023275] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our previous studies revealed the species-based difference of CYP24A1-dependent vitamin D metabolism. Although human CYP24A1 catalyzes both C-23 and C-24 oxidation pathways, rat CYP24A1 shows almost no C-23 oxidation pathway. We tried to identify amino acid residues that cause the species-based difference by site-directed mutagenesis. In the putative substrate-binding regions, amino acid residue of rat CYP24A1 was converted to the corresponding residue of human CYP24A1. Among eight mutants examined, T416M and I500T showed C-23 oxidation pathway. In addition, the mutant I500F showed quite a different metabolism of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] from both human and rat CYP24A1. These results strongly suggest that the amino acid residues at positions 416 and 500 play a crucial role in substrate binding and greatly affect substrate orientation. A three-dimensional model of CYP24A1 indicated that the A-ring and triene part of 1alpha,25(OH)2D3 could be located close to amino acid residues at positions 416 and 500, respectively. Our findings provide useful information for the development of new vitamin D analogs for clinical use.
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Affiliation(s)
- Hiromi Hamamoto
- Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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Mizwicki MT, Bula CM, Bishop JE, Norman AW. A perspective on how the Vitamin D sterol/Vitamin D receptor (VDR) conformational ensemble model can potentially be used to understand the structure-function results of A-ring modified Vitamin D sterols. J Steroid Biochem Mol Biol 2005; 97:69-82. [PMID: 16055325 DOI: 10.1016/j.jsbmb.2005.06.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The steroid hormone 1alpha,25(OH)(2)-Vitamin D(3) (1,25D) activates both genomic and non-genomic intracellular signaling cascades. It is also well recognized that co-incubation of 1,25D with its C-1 epimer, 1beta,25D (HL), suppresses the efficiency of the non-genomic signal activated by 1,25D alone and that its C-3 epimer, 3alpha-1,25D (HJ) is nearly as potent as 1,25D in suppressing PTH secretion, believed to be propagated by 1,25D's genomic signaling. Both these sterols lack the hypercalcemic effect induced by pharmacological doses of 1,25D and have reduced VDR affinity compared to 1,25D, as measured in a steroid competition assay. Recent functional studies suggest that the VDR is required for both non-genomic and genomic signaling. Along these lines we have recently proposed a Vitamin D sterol/VDR conformational ensemble model that posits the VDR contains two distinct, yet overlapping ligand binding sites, and that the potential differential stabilities of 1,25D and HL in these two pockets can be used to explain their different non-genomic signaling properties. The overlapping region is predominantly occupied by the sterol's A-ring when it is bound to either the genomic ligand binding pocket (G-pocket), defined by X-ray crystallography, or the alternative ligand binding pocket (A-pocket), discovered using in silico techniques (directed docking). Therefore, to gain further insight into the potential application of this model we docked the other A-ring diastereomer [(1beta,3alpha)=HH] of 1,25D and its 1- and 3-deoxy forms (25D and CF, respectively) to the A- and G-pockets to assess their potential stabilities in the pockets, relative to 1,25D. The models were then used to provide putative mechanistic arguments for their known structure-function experimental results. This model may provide new insights into how Vitamin D sterols that uncouple the unwanted hypercalcemic effect from attractive growth inhibitory/differentiation properties can do so by differentially stabilizing different subpopulations of VDR conformational ensemble members.
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Affiliation(s)
- Mathew T Mizwicki
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
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Abe D, Sakaki T, Kusudo T, Kittaka A, Saito N, Suhara Y, Fujishima T, Takayama H, Hamamoto H, Kamakura M, Ohta M, Inouye K. METABOLISM OF 2α-PROPOXY-1α,25-DIHYDROXYVITAMIN D3AND 2α-(3-HYDROXYPROPOXY)-1α,25-DIHYDROXYVITAMIN D3BY HUMAN CYP27A1 AND CYP24A1. Drug Metab Dispos 2005; 33:778-84. [PMID: 15764712 DOI: 10.1124/dmd.104.003038] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, we demonstrated that some A-ring-modified vitamin D3 analogs had unique biological activity. Of these analogs, 2alpha-propoxy-1alpha,25(OH)2D3 (C3O1) and 2alpha-(3-hydroxypropoxy)-1alpha,25(OH)2D3 (O2C3) were examined for metabolism by CYP27A1 and CYP24A1. Surprisingly, CYP27A1 catalyzed the conversion from C3O1 to O2C3, which has 3 times more affinity for vitamin D receptor than C3O1. Thus, the conversion from C3O1 to O2C3 by CYP27A1 is considered to be a metabolic activation process. Five metabolites were detected in the metabolism of C3O1 and O2C3 by human CYP24A1 including both C-23 and C-24 oxidation pathways. On the other hand, three metabolites of the C-24 oxidation pathway were detected in their metabolism by rat CYP24A1, indicating a species-based difference in the CYP24A1-dependent metabolism of C3O1 and O2C3 between humans and rats. Kinetic analysis revealed that the Km and kcat values of human CYP24A1 for O2C3 are, respectively, approximately 16 times more and 3 times less than those for 1alpha,25(OH)2D3. Thus, the catalytic efficiency, kcat/Km, of human CYP24A1 for O2C3 is only 2% of 1alpha,25(OH)2D3. These results and a high calcium effect of C3O1 and O2C3 in animal experiments using rats suggest that C3O1 and O2C3 are promising for clinical treatment of osteoporosis.
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Affiliation(s)
- Daisuke Abe
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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