title: Metabolism of selective 20-epi-vitamin D3analogs in rat osteosarcoma UMR-106 cells: Isolation and identification of four novel C-1 fatty acid esters of 1α,25-dihydroxy-16-ene-20-epi-vitamin D3.
abstract: Analogs of 1α,25-dihydroxyvitamin D3(S1) with 20-epi modification (20-epi analogs) possess unique biological properties. We previously reported that 1α,25-dihydroxy-20-epi-vitamin D3(S2), the basic 20-epi analog is metabolized into less polar metabolites (LPMs) in rat osteosarcoma cells (UMR-106) but not in a perfused rat kidney. Furthermore, we also noted that only selective 20-epi analogs are metabolized into LPMs. For example, 1α,25-dihydroxy-16-ene-20-epi-vitamin D3(S4), but not 1α,25-dihydroxy-16-ene-23-yne-20-epi-vitamin D3(S5) is metabolized into LPMs. In spite of these novel findings, the unequivocal identification of LPMs has not been achieved to date. We report here on a thorough investigation of the metabolism of S4 in UMR-106 cells and isolated two major LPMs produced directly from the substrate S4 itself and two minor LPMs produced from 3-epi-S4, a metabolite of S4 produced through C-3 epimerization pathway. Using GC/MS, ESI-MS and1H NMR analysis, we identified all the four LPMs of S4 as 25-hydroxy-16-ene-20-epi-vitamin D3-1-stearate and 25-hydroxy-16-ene-20-epi-vitamin D3-1-oleate and their respective C-3 epimers. We report here for the first time the elucidation of a novel pathway of metabolism in UMR-106 cells in which both 1α,25(OH)2-16-ene-20-epi-D3and 1α,25(OH)2-16-ene-20-epi-3-epi-D3undergo C-1 esterification into stearic and oleic acid esters.
authors.affiliation: The Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, United States.
authors.forename: Caroline Ceailles
authors.initials: CC
authors.lastname: Flarakos
authors.affiliation: The Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Weiskopf
authors.affiliation: Epimer, LLC, 1 Valley View Drive, North Smithfield, RI 02896, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: Robinson
authors.affiliation: Epimer, LLC, 1 Valley View Drive, North Smithfield, RI 02896, United States.
authors.forename: Guoshun
authors.initials: G
authors.lastname: Wang
authors.affiliation: The Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, United States. Electronic address: p.vouros@northeastern.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Vouros
authors.affiliation: Hoffmann-La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, United States.
authors.forename: Gino J
authors.initials: GJ
authors.lastname: Sasso
authors.affiliation: Hoffmann-La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, United States.
authors.forename: Milan R
authors.initials: MR
authors.lastname: Uskokovic
authors.affiliation: Epimer, LLC, 1 Valley View Drive, North Smithfield, RI 02896, United States.
authors.forename: G Satyanarayana
authors.initials: GS
authors.lastname: Reddy
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D002762:Cholecalciferol / Q000737:chemistry / Q000378:metabolism*; D004952:Esters / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D012516:Osteosarcoma / Q000378:metabolism; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D014807:Vitamin D / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
chemical_list: D004952:Esters; D005227:Fatty Acids; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D002762:Cholecalciferol; D002117:Calcitriol
keywords: 1α,25(OH)(2)-16-ene-20-epi-3-epi-D(3); 1α,25(OH)(2)-16-ene-20-epi-D(3); 1α,25(OH)(2)D(3); Fatty acid esters; Metabolism