Research Library
Reduction of murine mammary tumor metastasis by conjugated linoleic acid.
Authors: Hubbard NE, Lim D, Summers L, Erickson KL.
Source: Cancer Lett 2000 Mar 13;150(1):93-100
Recent studies have shown that conjugated linoleic acid (CLA) can inhibit the
initiation and thus, incidence of mammary tumors in rodents. The concentration
of CLA required for these effects was as low as 0.1% of the diet, with no
increased effects above 1%. To date, there is little evidence that CLA has any
effect on growth or metastasis of mammary tumors. In this report, we demonstrate
that CLA, at the concentrations used in previous studies, had a significant
effect on the latency, metastasis, and pulmonary tumor burden of transplantable
murine mammary tumors grown in mice fed 20% fat diets. The latency of tumors
from mice fed CLA was significantly increased when compared with the 0% CLA
control diet. The volume of pulmonary tumor burden, as a result of spontaneous
metastasis, decreased proportionately with increasing concentrations of dietary
CLA. With 0.5 and 1% CLA, pulmonary tumor burden was significantly decreased
compared to mice treated with the eicosanoid inhibitor, indomethacin and fed
diets containing no CLA. Tumors of mice fed as little as 0.1% CLA and as much as
1% had significantly decreased numbers of pulmonary nodules when compared with
diets containing no CLA. The decrease in the number of pulmonary nodules by CLA
was nearly as effective as indomethacin, a known suppressor of tumor growth and
metastasis in this malignant model. These data suggest that effects of CLA on
mammary tumorigenesis may go beyond the reported alterations in tumor incidence
and effect later stages, especially metastasis.