Figure 1: Contribution of HO-1 and c-FLIPL to the regulation of TNF signalling in monocytes and acute myeloid leukemia cells (AML).

(A) In monocytes, engagement of TNFR1 by TNFα induces activation of NF-κB, leading to up-regulation of FLIP and inhibition of cell death, however inactivation of NF-κB (B) prevents FLIP neosynthesis, allowing caspase activation and apoptosis. (C) AML cells are resistant to TNFα-induced apoptosis, even upon inactivation of NF- κB (D), due to the up-regulation of HO-1. (E) Simultaneous inactivation of c-FLIP and HO-1 enhances TNF-induced cell death.