Combined Treatment of STI571 (Glivec) and Curcumin Synergistically Suppresses the Growth of K562 Cells Via Inhibition of Bcr-Abl Pathway.

Curcumin, biologically active compound extracted from rhizomes of Curcuma species, has been shown to possess potent anti-inflammatory and anti-tumor properties. As such, curcumin caused dose-dependent apoptosis of K562 cells, which is preceded by the activation of caspase 3. In addition, phosphorylation of Erk was effectively inhibited by curcumin. These findings leaded us to investigate the effects of combined treatment of curcumin and STI571 on K562 cells. With combined treatments, expression of Bcl-2, -XL, and Bid were dramatically down-regulated. In addition, the activity of caspase-3 was 2 fold higher than compared with either treatment alone. Cyclin D1 and its related proteins were down-regulated. In addition, combined treatment of curcumin and STI571 dramatically inhibited phoryphorylation of abl and its downstream proteins such as Src kinases and MAPK in K562 cells stimulated by IL-3. Taken together, our data suggested that curcumin potentiated the effects of STI571 in CML.