Inhibition of tumor necrosis factor-α enhances apoptosis induced by nuclear factor-κB inhibition in leukemia cells

Inhibition of nuclear factor-κB (NF-κB) results in antitumor activity in leukemia cells, and may be a potential therapeutic strategy for the treatment of leukemia. However, a significant limitation of NF-κB inhibition in the treatment of leukemia is the low efficiency of this technique. NF-κB inhibitor treatment induces apoptosis in leukemia cells; however, it additionally causes inflammatory molecules to induce increased sensitivity of healthy hematopoietic cells to cell death signals, therefore limiting its clinical applications. Tumor necrosis factor-α (TNF-α) is a key regulator of inflammation, and induces a variety of actions in leukemic and healthy hematopoietic cells. TNF-α induces NF-κB-dependent and -independent survival signals, promoting the proliferation of leukemia cells. However, in healthy hematopoietic cells, TNF-α induces death signaling, an effect which is enhanced by the inhibition of NF-κB. Based on these observations, the present study hypothesized that inhibition of TNF-α signaling may be able to protect healthy hematopoietic cells and other tissue cells, while increasing the anti-leukemia effects of NF-κB inhibition on leukemia cells. The role and underlying molecular mechanisms of TNF-α inhibition in the regulation of NF-κB inhibition-induced apoptosis in leukemia cells was therefore investigated in the present study. The results indicated that inhibition of TNF-α enhanced NF-κB inhibition-induced apoptosis in leukemia cells. It was also revealed that protein kinase B was significant in the regulation of TNF-α and NF-κB inhibition-induced apoptosis. During this process, intrinsic apoptotic pathways were activated. A combination of NF-κB and TNF-α inhibition may be a potential specific and effective novel therapeutic strategy for the treatment of leukemia.