Definition

An orally bioavailable, second mitochondria-derived activator of caspases (SMAC)-mimetic and an antagonist of inhibitor of apoptosis proteins (IAPs), with potential apoptosis-inducing and antineoplastic activities. Upon oral administration, IAP antagonist TQB3728 selectively targets, binds to and inhibits the activity of IAPs including X chromosome-linked IAP (XIAP) and cellular IAPs 1 (c-IAP1) and 2 (c-IAP2). This may restore and promote the induction of apoptosis through apoptotic signaling pathways and enhance proteasomal degradation of IAPs. Additionally, TQB3728 may work synergistically with cytotoxic drugs to overcome tumor cell resistance to apoptosis. IAPs are overexpressed by many cancer cell types, suppressing apoptosis by binding and inhibiting active caspases-3, -7 and -9 via their BIR (baculoviral lAP repeat) domains.