Curcumin has been shown to induce apoptosis in various malignant cancer cell lines One mechanism of curcumin-induced apoptosis is through the PI3K/Akt signaling pathway. Akt, also known as protein kinase B (PKB), is a member of the family of phosphatidylinositol 3-OH-kinase regulated Ser/Thr kinases The active Akt regulates cell survival and proliferation, and inhibits apoptosis In this study we found that curcumin induces apoptotic cell death in MCF-7 cells, as assessed by MTT assay, DNA ladder formation, PARP cleavage, p53 and Bax induction At apoptotic inducing concentration, curcumin induces a dramatic Akt phosphorylation, accompanied by an increased phosphorylation of glycogen synthase kinase (GSK3 beta), which has been considered to be a pro-growth signaling molecule Combining curcumin with PI3K inhibitor, LY290042, synergizes the apoptotic effect of curcumin The inhibitor LY290042 was capable of attenuating curcumin-induced Akt phosphorylation and activation of GSK3 beta All together, our data suggest that blocking the PI3K/Akt survival pathway sensitizes the curcumin-induced apoptosis in MCF-7 cells (C) 2010 Elsevier Inc All rights reserved.