title: Hypoxia remodels the composition of the constituent ceramide species of HexCer and Hex2Cer with phytosphingosine and hydroxy fatty acids in human colon cancer LS174T cells.
abstract: Oxygen-requiring enzymes, such as Δ4-desaturase (dihydroceramide desaturase), sphingolipid Δ4-desaturase/C-4-hydroxylase, and fatty acid 2-hydroxylase are involved in ceramide synthesis. We prepared free ceramides, sphingomyelins and glycosphingolipids (GSLs) from cancer cells cultivated under conditions of normoxia and hypoxia, and analyzed these compounds using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Human colon cancer LS174T cells were employed because these cells highly express hydroxyl fatty acids and phytosphingosine (t18:0) which are expected to be greatly influenced by changes in oxygen levels. As expected, the populations of dihydro-species of free ceramide and sphingomyelin with C16:0 non-hydroxy fatty acid were elevated, and the populations of HexCers and Hex2Cers, composed of C16:0 or C16:0 hydroxy fatty acid (C16:0h), and sphingosine (d18:1) or t18:0, were decreased under hypoxia. However, appreciable populations of HexCer and Hex2Cer species of C24:0 or C24:0h and t18:0 remained. These results suggest that the individual species of GSLs with fatty acids possessing different alkyl chain lengths, either non-hydroxy fatty acids or hydroxyl fatty acids, may be metabolized individually.
authors.affiliation: Department of Medical Technology, Nagoya University Graduate School of Health Sciences, Daiko-Minami 1-1-20, Higashi-ku, Nagoya, 461-8673, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Medical Technology, Nagoya University Graduate School of Health Sciences, Daiko-Minami 1-1-20, Higashi-ku, Nagoya, 461-8673, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tamiya-Koizumi
authors.affiliation: Shimadzu Corporation, Nishinokyo-Kuwabaracho 1, Nakagyo-ku, Kyoto, 604-8511, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Department of Medical Technology, Nagoya University Graduate School of Health Sciences, Daiko-Minami 1-1-20, Higashi-ku, Nagoya, 461-8673, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Murate
authors.affiliation: Research Complex for the Medicine Frontiers, Aichi Medical University, Yazako, Nagakute, Aichi, 480-1195, Japan.
authors.forename: Reiji
authors.initials: R
authors.lastname: Kannagi
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Nihon Pharmaceutical University, Komuro 10281, Inamachi, Saitama, 362-0806, Japan. mkyogashi@nichiyaku.ac.jp.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kyogashima
mesh_terms: D018938:Caco-2 Cells; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002518:Ceramides / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D003110:Colonic Neoplasms / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D006028:Glycosphingolipids / Q000737:chemistry; D006801:Humans; D016014:Linear Models; D013058:Mass Spectrometry; D010100:Oxygen / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013109:Sphingomyelins / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000737:chemistry; D053719:Tandem Mass Spectrometry
chemical_list: D002518:Ceramides; D005227:Fatty Acids; D006028:Glycosphingolipids; D013109:Sphingomyelins; C012491:phytosphingosine; D013110:Sphingosine; D010100:Oxygen
keywords: Ceramides; Glycosphingolipids; Hydroxy-fatty acid; Hypoxia; Phytosphingosine; Sphingolipid-species