Inhibition of Curcumin on ZAKα Activity Resultant in Apoptosis and Anchorage-Independent Growth in Cancer Cells

Curcumin, a popular yellow pigment of the dietary spice turmeric, has been reported to inhibit cell growth and to induce apoptosis in a wide variety of cancer cells. Although numerous studies have investigated anticancer effects of curcumin, the precise molecular mechanism of action remains unidentified. Whereas curcumin mediates cell survival and apoptosis through mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-kappa B) signaling cascades, its impact on the upstream regulation of MAPK is unclear. The leucine-zipper and sterile-alpha motif kinase alpha (ZAK alpha), a mitogen-activated protein kinase kinase kinase (MAP3K), activates the c-Jun N-terminal kinase (JNK) and NF-kappa B pathway. This paper investigated the prospective involvement of ZAK alpha in curcumin-induced effects on cancer cells. Our results suggest that the antitumor activity of curcumin is mediated via a mechanism involving inhibition of ZAK alpha activity.