Dietary supplementation with curcumin enhances metastatic growth of Lewis lung carcinoma in mice

Abstract

Our study investigated the effects of dietary supplementation with curcumin [(1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] on spontaneous metastasis of Lewis lung carcinoma (LLC) in C57BL/6 mice. Mice were fed with the AIN93G control diet or with the diet supplemented with 2 or 4% curcumin for 5 weeks at which time they were injected subcutaneously with 2.5 × 105 viable LLC cells. The subcutaneous primary tumor was surgically removed when it reached ∼ 8 mm in diameter, and the experiment was terminated 10 days after the surgery. There was no difference in pulmonary metastatic yield among the groups. Curcumin supplementation at either dietary level did not significantly increase the size of metastatic tumors; however, the combined data from both curcumin groups showed that curcumin treatment increased metastatic tumor cross-sectional area by 46% (p < 0.05) and volume by 70% (p < 0.05) compared to the controls. Curcumin supplementation increased plasma concentrations of angiogenic factors angiogenin (p < 0.05), basic fibroblast growth factor (p < 0.05) and vascular endothelial growth factor (p < 0.05), as well as inflammatory cytokines interleukin-1β (p < 0.05) and monocyte chemotactic protein-1 (p < 0.05), compared to the controls. These results demonstrate that curcumin does not prevent metastasis and indicate that it can enhance metastatic growth of LLC in mice, perhaps through upregulation of angiogenesis and inflammation. What's new? Research has suggested that curcumin may reduce malignant formation and growth. In this study, however, dietary supplementation with curcumin in mice was found to enhance metastatic growth of Lewis lung carcinoma. This enhancement was associated with increases in plasma concentrations of angiogenic factors and inflammatory cytokines, which are expressed in many human cancers. The potential role of curcumin in facilitating the development, growth, and spread of malignancies with rapid progression warrants further investigation. Copyright © 2012 UICC.