Curcumin, the active ingredient from the spice turmeric (Curcuma longa Linn), is known to be an anti-oxidant and an anti-inflammatory agent. It has been demonstrated recently to possess anti-angiogenic effects and pro-apoptotic activities against Ehrlich ascites tumor cells. In the current study, curcumin was found to be cytotoxic in vitro for B16-R melanoma cells resistant to doxorubicin either cultivated as monolayers or grown in three-dimensional (3-D) cultures (spheroids). We have demonstrated that the cytotoxic effect observed in the 2 culture types can be related to the induction of programmed cell death. In our in vivo studies, we examined the effectiveness of a prophylactic immune preparation of soluble proteins from B16-R cells, or a treatment with curcumin as soon as tumoral appearance, alone or in combination, on the murine melanoma B16-R. The combination treatment resulted in substantial inhibition of growth of B16-R melanoma, whereas each treatment by itself showed little effect. Moreover, animals receiving the combination therapy exhibited an enhancement of their humoral anti-soluble B16-R protein immune response and a significant increase in their median survival time (> 82.8% vs. 48.6% and 45.7% respectively for the immunized group and the curcumin-treated group). Our study shows that curcumin may provide a valuable tool for the development of a therapeutic combination against the melanoma.
Copyright 2004 Wiley-Liss, Inc.