Effects of a fish oil–based emulsion on rat hepatoma cell invasion in culture

Objective Total parenteral nutrition containing a lipid emulsion is often employed after surgical tumor resection. This study investigated the effects of a fish oil–based infusion on rat hepatoma cell invasion. Methods Rat ascites hepatoma cell line AH109A was precultured with a fish oil–based or safflower oil–based emulsion for 48 h. Changes in membranous fatty acid composition were evaluated by gas chromatography. The invasiveness of hepatoma cells was assessed by coculturing with mesentery-derived mesothelial cells. To examine ex vivo effects of the fish oil–based infusion on hepatoma invasion, sera were prepared from rats infused with fish oil– or safflower oil–based emulsion and the effects of these sera were assessed. To clarify the mechanism of inhibition of invasion by the fish oil–based emulsion, the effects of prostaglandin (PG) E2 and PGE3 on invasion were examined. Results Pretreatment with the fish oil–based emulsion reduced invasiveness without affecting growth compared with the safflower oil–based emulsion. Pretreatment with the sera from rats infused with the fish oil–based emulsion also reduced invasiveness compared with the sera from rats infused with the safflower oil–based emulsion. The addition of PGE2 eliminated the inhibitory effect of the fish oil–based emulsion, and the addition of PGE3 reduced the invasiveness of hepatoma cells pretreated with the safflower oil–based emulsion. Conclusion These results suggest that the fish oil–based emulsion may have anti-invasive effects. Changes in the membranous fatty acid composition and consequent changes in the prostaglandins produced may be involved in this inhibitory effect.