Effects of eicosapentaenoic and docosahexaenoic acid on cell growth and prostaglandin E and leukotriene B production by a human breast cancer cell line (MDA-MB-231).

We investigated the in vitro effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with or without the addition of linoleic acid (LA), on cell growth and prostaglandin E (PGE) and leukotriene B (LTB) secretion by a human breast cancer cell line (MDA-MB-231). With or without the addition of LA, EPA and DHA suppressed cell growth and thymidine incorporation and reduced the secretion of PGE and LTB. In a univariate analysis, cell growth was significantly associated with both LTB and PGE concentrations when cells were treated with DHA or EPA, independent of the addition of LA. However, multivariate regression analysis showed that cell growth was more closely associated with the PGE concentration rather than the LTB concentration. These data suggest that both EPA and DHA suppress cell proliferation in the MDA-MB-231 cell line by inhibition of the cyclooxygenase rather than the lipoxygenase pathways. However, the exact mechanism underlying the antitumor activity of EPA and DHA remains unclear.