Inhibitor of apoptosis protein family (IAP family) (IAP)

The Inhibitor of Apoptosis Protein (IAP) family consists of eight human proteins, such as XIAP, cIAP1, and cIAP2, which serve as critical endogenous regulators of programmed cell death and inflammatory signaling [7, 10]. These proteins are characterized by the presence of one or more baculoviral IAP repeat (BIR) domains, which facilitate interactions with caspases and other signaling molecules [7, 12]. IAPs are frequently overexpressed in a wide range of malignancies, where they promote tumor cell survival, confer resistance to chemotherapy, and modulate the tumor microenvironment by activating NF-kappaB pathways [4, 9]. APG-1387 (Dasminapant) is a clinical-stage, bivalent small-molecule SMAC mimetic designed to antagonize these proteins by mimicking the dimeric form of the endogenous IAP inhibitor SMAC/DIABLO [1, 6]. By binding to the BIR domains, APG-1387 induces the rapid degradation of cIAP1/2 and blocks the anti-apoptotic activity of XIAP, thereby restoring the apoptotic machinery and enhancing the efficacy of immune checkpoint inhibitors and cytotoxic therapies [3, 13, 16]. Additionally, APG-1387 is being explored for its potential to achieve a functional cure in chronic hepatitis B by selectively inducing apoptosis in infected hepatocytes [6].

Other names

BIRC familyBaculoviral IAP repeat-containing proteinscIAPXIAPML-IAPSurvivinNAIPBruceILP-2

APG-1387 is a bivalent SMAC mimetic that antagonizes the Inhibitor of Apoptosis Protein (IAP) family by mimicking the endogenous pro-apoptotic protein SMAC/DIABLO [1, 3]. It binds with high affinity to the Baculoviral IAP Repeat (BIR) domains of XIAP, cIAP1, and cIAP2 [2, 5]. This interaction triggers the rapid auto-ubiquitination and proteasomal degradation of cIAP1 and cIAP2, which leads to the stabilization of NF-kappaB-inducing kinase (NIK) and activation of the non-canonical NF-kappaB pathway [11, 12]. Furthermore, by sequestering XIAP, APG-1387 relieves the inhibition of caspases-3, -7, and -9, thereby lowering the threshold for apoptosis and sensitizing tumor cells to TNF-alpha and TRAIL-mediated death signals [4, 11].