Abstract
Curcumin (diferuloyl methane), the major pigment from the rhizome of Curcuma longa L., has been widely studied for its tumor-inhibiting properties. Recent studies indicate that curcumin can modify cell receptor binding, it also affects intracellular signalling reactions. Curcumin-treated B16F10 melanoma cells formed eight-fold fewer lung metastases in C57BL6 mice. In the cell adhesion assays, curcumin-treated cells showed a dose-dependent reduction in their binding to four extracellular matrix (ECM) proteins. The binding to fibronectin, vitronectin, and collagen IV decreased by over 50% in 24 hours, and by 100% after 48 hours of curcumin treatment, it persisted at this level even after 15 days of cultivating cells in curcumin-free medium. Curcumin-treated cells showed a marked reduction in the expression of alpha5beta1 and alpha(v)beta3 integrin receptors. In addition, curcumin treatment inhibited pp125 focal adhesion kinase (FAK), tyrosine phosphorylation of a 120 kD protein, and collagenase activity. Curcumin enhances the expression of antimetastatic proteins, tissue inhibitor metalloproteinase (TIMP)-2, nonmetastatic gene 23 (Nm23), and E-cadherin. In this article we report on the effect of curcumin on the expression of integrin, TIMP-2, Nm23, E-cadherin, adhesion, and metalloproteinase activity.
