title: 5-aminolevulinic acid induced lipid peroxidation after light exposure on human colon carcinoma cells and effects of alpha-tocopherol treatment.
abstract: This work relates to studies on modes of phototoxicity by protoporphyrin (PpIX) after incubation of 5-aminolevulinic acid (5-ALA) on cultured cells. Lipid peroxidation in the 5-ALA incubated primary adenocarcinoma cells from the rectosigmoid colon (WiDr cells) was determined by measurement of protein-associated thiobarbituric acid reactive substances (TBARS). TBARS were increased 2-fold in cells treated with 2 mM 5-ALA for 3.5 h in serum enriched medium. After illumination of 5-ALA incubated cells, TBARS were formed in a light dose dependent manner. TBARS analysis were compared with high-performance liquid chromatography (HPLC) analysis of malondialdehyde, and results indicate that 90% of the thiobarbituric reactive substances were due to malondialdehyde. Pretreating WiDr cells with alpha-tocopherol for 48 h inhibits the cytotoxic effect of 5-ALA and increases 5-fold the light dose needed to kill 50% of the cells. Pretreatment with alpha-tocopherol shows a considerable decrease (about 80%) on TBARS formation after illumination. The cellular content of alpha-tocopherol was determined by HPLC and found to be 15.3 pmol/10(6) cells.
authors.affiliation: Department of Clinical Chemistry, Institute of Laboratory Medicine, Medical Faculty, Norwegian University of Science and Technology, N-7006, Trondheim, Norway.
authors.forename: O A
authors.initials: OA
authors.lastname: Gederaas
authors.forename: J W
authors.initials: JW
authors.lastname: Lagerberg
authors.forename: O
authors.initials: O
authors.lastname: Brekke
authors.forename: K
authors.initials: K
authors.lastname: Berg
authors.forename: T M
authors.initials: TM
authors.lastname: Dubbelman
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008027:Light; D015227:Lipid Peroxidation / Q000187:drug effects*; D008315:Malondialdehyde / Q000378:metabolism / Q000528:radiation effects; D017319:Photosensitizing Agents / Q000494:pharmacology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism / Q000528:radiation effects; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D014810:Vitamin E / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D017319:Photosensitizing Agents; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D008315:Malondialdehyde; D000622:Aminolevulinic Acid