Apple extracts attenuate tumor necrosis factor-α-induced nuclear factor-κB activation by inhibiting IκB kinase and proteasome in A549 human non-small lung carcinoma cells

Abstract

Apples contain a variety of phytochemicals and health benefits of apple consumption are widely recognized in reducing the risks of chronic diseases such as cancer. However, the mechanisms of apples in inhibiting lung cancer cell proliferation are not fully understood. The present study examined the role of apple extracts in suppressing nuclear factor (NF)-κB activation in A549 human lung cancer cells. Incubation with apple extracts at doses of 10 and 20 mg(fresh apple)/mL significantly inhibited tumor necrosis factor (TNF)-α-induced NF-κB activation in A549 cells (p<0.05). Apple extracts suppressed phosphorylation of inhibitor of NF-κB (IκB-α) at doses of 10 and 20 mg (fresh apple)/mL and inhibited proteasomal activity at doses of 5, 10, and 20 mg(fresh apple)/mL (p<0.05). These results indicate that apple extracts inhibit TNF-α-induced NF-κB activation in A549 lung cancer cells by suppressing both of IκB kinase (IKK) activity and proteasomal activity.