title: Cytotoxity of the trans10,cis12 isomer of conjugated linoleic acid on rat hepatoma and its modulation by other fatty acids, tocopherol, and tocotrienol.
abstract: This study was performed to evaluate the isomer-specific cytotoxic effects of conjugated linoleic acid (CLA) on rat hepatoma dRLh-84 cells in vitro. A 10trans,12cis (10t,12c)-CLA showed a strong cytotoxic effect on dRLh-84 cells in culture, whereas no such effect was observed with 9cis,11trans (9c,11t)-CLA or linoleic acid. The optimum concentration for induction of cytotoxicity by 10t,12c-CLA was 5 to 10 microM, but the effect was alleviated at higher concentrations. Coincubation with oleic or palmitoleic acid and 10t,12c-CLA cancelled the cytotoxic effect, but other major saturated or polyunsaturated fatty acids and eraidic acid did not interfere with 10t,12c-CLA-induced cytotoxity. The cytotoxic effect was also alleviated by alpha-tocopherol (alpha-toc) and alpha-tocotrienol but not by any other antioxidant reagent examined. Significant cytotoxicity of 10t,12c-CLA was detected after only a 15-min incubation, and the most noticeable effect was seen after 3 h. After incubation with 10t,12c-CLA at 10 microM, an additional 90 microM of 10t,12c-CLA or 100 microM of alpha-toc was also able to alleviate the cytotoxicity. When cells were treated with 10 microM 10t,12c-CLA for more than 48 h, treatment with additional CLA or alpha-toc could not prevent cell death.
authors.affiliation: Department of Biochemistry and Applied BioScience, Faculty of Agriculture, Miyazaki University, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan. myamasaki@cc.miyazaki-u.ac.jp
authors.forename: Masao
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Eri
authors.initials: E
authors.lastname: Nishida
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nou
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tachibana
authors.forename: Koji
authors.initials: K
authors.lastname: Yamada
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D051381:Rats; D024505:Tocopherols / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D024508:Tocotrienols / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D005227:Fatty Acids; D044243:Linoleic Acids, Conjugated; D024508:Tocotrienols; D024505:Tocopherols