The growth inhibitory effect of conjugated linoleic acid on a human hepatoma cell line, HepG2, is induced by a change in fatty acid metabolism, but not the facilitation of lipid peroxidation in the cells

Miki Igarashi, Teruo Miyazawa

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

We investigated the growth inhibitory effect of conjugated linoleic acid (CLA) on HepG2 (human hepatoma cell line), exploring whether the inhibitory action occurs via lipid peroxidation in the cells. When the cells were incubated up to 72 h with 5-40 μM of CLA (a mixture of 9c,11t-18:2 and 10t,12c-18:2), cell proliferation was clearly inhibited in a dose and time dependent manner but such an inhibition was not confirmed with linoleic acid (LA). In order to evaluate the possible contribution of lipid peroxidation exerted by CLA to cell growth inhibition, α-tocopherol (5-20 μM) and BHT (1-10 μM) as potent antioxidants were added to the medium with CLA (20 μM), which did not restore cell growth at all. Furthermore, after 72 h incubation, the membranous phospholipid hydroperoxide formation in the CLA-supplemented cells was suppressed respectively to 25% and 50% of that in LA-supplemented cells and control cells. No difference was observed by a conventional lipid peroxide assay, the TBA test, between CLA-supplemented cells and LA-supplemented cells. Although the cellular lipid peroxidation was not stimulated, lipid contents (triacylglycerol, total cholesterol and free cholesterol) and fatty acid contents (palmitic acid, palmitoleic acid and stearic acid) markedly increased in CLA-supplemented cells compared with LA-supplemented and control cells. Moreover, supplementation with 20 μM LA and 20 μM arachidonic acid profoundly interfered with the inhibitory effect of CLA in HepG2. These results suggest that the growth inhibitory effect of CLA on HepG2 is due to changes in fatty acid metabolism but not to lipid peroxidation.

Original languageEnglish
Pages (from-to)162-171
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1530
Issue number2-3
DOIs
Publication statusPublished - 2001 Feb 26

Keywords

  • Cell growth inhibition
  • Conjugated linoleic acid
  • Hepatoma
  • Linoleic acid
  • Lipid peroxidation
  • Phospholipid hydroperoxide

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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