Conjugated linoleic acid (CLA)-enriched milk fat inhibits growth and modulates CLA-responsive biomarkers in MCF-7 and SW480 human cancer cell lines

Milk enriched in conjugated linoleic acid (CLA) was obtained from cows on pasture supplemented with full-fat rapeseeds (FFR; 2·26g cis 9, trans 11 (c9, t11)-CLA/100g fatty acid methyl esters) and full-fat soyabeans (1·83g c9, t11-CLA/100g fatty acid methyl esters). A control milk fat (1·69g c9, t11-CLA/100g fatty acid methyl esters) was obtained from cows fed on pasture only. The present study assessed the potency of the CLA-enriched milk fats to modulate biomarkers that had previously been observed to respond to c9, t11-CLA in the MCF-7 and SW480 cell lines. Cell numbers decreased (P<0·05) by up to 61 and 58% following the incubation of MCF-7 and SW480 cells, respectively, for 4d with milk fats (yielding CLA concentrations between 60·2 and 80·6μM). The FFR milk fat, containing the highest CLA content, increased (P<0·05) [14C]arachidonic acid (AA) uptake into the monoacylglycerol fraction of MCF-7 and SW480 cells while it decreased (P<0·05) uptake into the phospholipid fraction of the latter. This milk fat also decreased (P<0·05) [14C]AA conversion to prostaglandin (PG) E2 while increasing conversion to PGF2α in both cell lines. All milk-fat samples increased (P<0·05) lipid peroxidation as measured by 8-epi-PGF2α in both cell lines. In SW480 cells the milk-fat samples decreased (P<0·05) bcl-2 and cytosolic glutathione levels while increasing (P<0·05) membrane-associated annexin V levels. All milk-fat samples decreased (P<0·05) the expression of ras in SW480 cells. These data suggest that milk-fat CLA was effective at modulating synthetic CLA-responsive biomarkers

CLA - A Health-Promoting Component of Animal and Milk Fat

End of Project ReportTeagasc acknowledges with gratitude financial assistance for this project from the Dairy Levy Fund and by the EU (Concerted Action FAIR-CT98-3671 and SM & T4 CT97-2144).In the recent past, there has been considerable interest in the potential health-promoting properties of conjugated linoleic acid (CLA), a fatty acid produced naturally in ruminant animals. CLA has been shown to be a very effective anti-cancer agent in animal models and cell culture studies, as well as being capable of retarding the initiation and progression of heart disease (atherosclerosis). It has also been shown to have potential as a growth promoter and is capable of improving feed efficiency. Hence from a human health viewpoint, it appears desirable to increase CLA levels in foods to protect against disease and enhance general health and well-being. The primary sources of CLA are animal fats (including dairy fats) derived from ruminant animals while vegetable fats and oils contain significantly lower levels. This project was aimed at enriching the CLA content of dairy foods through animal dietary manipulation, and milk fat fractionation.Dairy Levy FundEuropean Unio