Journal of Lipid Research (Feb 2004)

Dietary α-linolenic acid reduces COX-2 expression and induces apoptosis of hepatoma cells

  • A. Vecchini,
  • V. Ceccarelli,
  • F. Susta,
  • P. Caligiana,
  • P. Orvietani,
  • L. Binaglia,
  • G. Nocentini,
  • C. Riccardi,
  • G. Calviello,
  • P. Palozza,
  • N. Maggiano,
  • P. Di Nardo

Journal volume & issue
Vol. 45, no. 2
pp. 308 – 316

Abstract

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Fatty acid synthetase (FAS) is overexpressed in various tumor tissues, and its inhibition and/or malonyl-CoA accumulation have been correlated to apoptosis of tumor cells. It is widely recognized that both ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) depress FAS expression in liver, although epidemiological and experimental reports attribute antitumor properties only to ω-3 PUFA. Therefore, we investigated whether lipogenic gene expression in tumor cells is differently regulated by ω-6 and ω-3 PUFAs. Morris hepatoma 3924A cells were implanted subcutaneously in the hind legs of ACI/T rats preconditioned with high-lipid diets enriched with linoleic acid or α-linolenic acid. Both-high lipid diets depressed the expression of FAS and acetyl-CoA carboxylase in tumor tissue, this effect correlating with a decrease in the mRNA level of their common sterol regulatory element binding protein-1 transcription factor. Hepatoma cells grown in rats on either diet did not accumulate malonyl-CoA. Apoptosis of hepatoma cells was induced by the α-linolenic acid-enriched diet but not by the linoleic acid-enriched diet.Therefore, in this experimental model, apoptosis is apparently independent of the inhibition of fatty acid synthesis and of malonyl-CoA cytotoxicity. Conversely, it was observed that apoptosis induced by the α-linolenic acid-enriched diet correlated with a decrease in arachidonate content in hepatoma cells and decreased cyclooxygenase-2 expression.

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