Principal Investigator:
Kent L. Erickson
University of California, DavisCo-investigators: Neil E. Hubbard, Debora Lim
Conjugated linoleic acid (CLA) is a fatty acid found in some sources of dietary fat and can be a potent chemoprotective agent against mammary tumors in experimental animals. We have recently published evidence that CLA significantly reduced breast tumor spread in mice.
In this study, a mouse model that displays many of the characteristics of human tumors was used to investigate the mechanism of how CLA reduces the malignant process. The focus to date has been to study the effect of dietary CLA on the expression of proteins that enhance or reduce the ability of tumors to grow and spread or metastasize. For that study, mice were divided into dietary groups where the food consumed was similar except for the type and amount of CLA. Our observation was that animals fed the diets that had no CLA expressed proteins that enhanced tumorigenesis (the production of tumors) while animals fed diets that contained CLA expressed lower levels of the proteins that are known to enhance tumorigenesis. We also observed that the time it took tumors to establish was longer in animals that were fed the different CLA diets. Moreover, fewer tumor cells metastasized to the lung in animals fed CLA; that reduction was observed with as little as 0.1% CLA in the diet. CLA also appears to reduce the ability of those metastatic breast tumor cells to lodge in the lung and grow.
Thus, CLA can be an important chemo-protective agent in breast cancer and that one mechanism may involve alteration of proteins that are known to enhance tumorigenesis. This study provides additional evidence to support a phase I clinical trial of CLA since CLA at this level does not appear to be harmful to humans.