Structure-Based Design, Synthesis, and Evaluation of Conformationally Constrained Mimetics of the Second Mitochondria-Derived Activator of Caspase That Target the X-Linked Inhibitor of Apoptosis Protein/Caspase-9 Interaction Site

MIHA is an inhibitor of apoptosis protein (IAP) that can inhibit cell death by direct interaction with caspases, the effector proteases of apoptosis. DIABLO is a mammalian protein that can bind to IAPs and antagonize their antiapoptotic effect, a function analogous to that of the proapoptotic Drosophila molecules, Grim, Reaper, and HID. Here, we show that after UV radiation, MIHA prevented apoptosis by inhibiting caspase 9 and caspase 3 activation. Unlike Bcl-2, MIHA functioned after release of cytochrome c and DIABLO from the mitochondria and was able to bind to both processed caspase 9 and processed caspase 3 to prevent feedback activation of their zymogen forms. Once released into the cytosol, DIABLO bound to MIHA and disrupted its association with processed caspase 9, thereby allowing caspase 9 to activate caspase 3, resulting in apoptosis.

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Design, synthesis and evaluation of inhibitor of apoptosis protein (IAP) antagonists that are highly selective for the BIR2 domain of XIAP

Bioorganic & Medicinal Chemistry Letters ◽

10.1016/j.bmcl.2013.04.096 ◽

2013 ◽

Vol 23 (14) ◽

pp. 4253-4257 ◽

Cited By ~ 10

Author(s):

Robert J. Ardecky ◽

Kate Welsh ◽

Darren Finlay ◽

Pooi San Lee ◽

Marcos González-López ◽

...

Keyword(s):

Inhibitor Of Apoptosis ◽

Design Synthesis ◽

Inhibitor Of Apoptosis Protein ◽

Apoptosis Protein

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Molecular Cloning of ILP-2, a Novel Member of the Inhibitor of Apoptosis Protein Family

Molecular and Cellular Biology ◽

10.1128/mcb.21.13.4292-4301.2001 ◽

2001 ◽

Vol 21 (13) ◽

pp. 4292-4301 ◽

Cited By ~ 63

Author(s):

Bettina W. M. Richter ◽

Samy S. Mir ◽

Lisa J. Eiben ◽

Jennifer Lewis ◽

Stephanie Birkey Reffey ◽

...

Keyword(s):

Molecular Cloning ◽

Inhibitor Of Apoptosis ◽

Physical Interaction ◽

Caspase 9 ◽

Inhibitor Of Apoptosis Protein ◽

Normal Tissues ◽

Apoptosis Protein ◽

Processed Form

ABSTRACT Inhibitor of apoptosis protein (IAP)-like protein-1 (ILP-1) (also known as X-linked IAP [XIAP] and mammalian IAP homolog A [MIHA]) is a potent inhibitor of apoptosis and exerts its effects, at least in part, by the direct association with and inhibition of specific caspases. Here, we describe the molecular cloning and characterization of a human gene related to ILP-1, termed ILP-2. Despite high homology to ILP-1, ILP-2 is encoded by a distinct gene, which in normal tissues is expressed solely in testis. In contrast to ILP-1, overexpression of ILP-2 had no protective effect on apoptosis mediated by Fas (also known as CD95) or tumor necrosis factor. However, ILP-2 potently inhibited apoptosis induced by overexpression of Bax or by coexpression of caspase 9 with Apaf-1, and preincubation of cytosolic extracts with ILP-2 abrogated caspase activation in vitro. A processed form of caspase 9 could be coprecipitated with ILP-2 from cells, suggesting a physical interaction between ILP-2 and caspase 9. Thus, ILP-2 is a novel IAP family member with restricted specificity for caspase 9.

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Resistance of bone marrow-derived macrophages to apoptosis is associated with the expression of X-linked inhibitor of apoptosis protein in primary cultures of bone marrow cells

Biochemical Journal ◽

10.1042/bj3530299 ◽

2001 ◽

Vol 353 (2) ◽

pp. 299-306 ◽

Cited By ~ 18

Author(s):

Hong LIN ◽

Catheryne CHEN ◽

Ben D.-M. CHEN

Keyword(s):

Bone Marrow ◽

Caspase 3 ◽

Bone Marrow Cells ◽

Primary Cultures ◽

Precursor Cells ◽

Inhibitor Of Apoptosis ◽

Caspase 9 ◽

Prolonged Incubation ◽

Inhibitor Of Apoptosis Protein ◽

Apoptosis Protein

In this study we investigated the underlying mechanisms that confer resistance on mature macrophages with the use of macrophage colony-stimulating factor (M-CSF)-induced bone marrow-derived macrophages (BMDM). In the presence of M-CSF, immature precursor cells were induced to undergo proliferation and differentiation into mature macrophages in vitro with cell morphology similar to that of tissue macrophages by day 7Ő10. Immunoblot analyses showed that bone marrow precursors express appreciable levels of caspase-3 and caspase-9 but no or very low levels of c-fms (M-CSF receptor) and the apoptosis regulators X-linked inhibitor of apoptosis protein (XIAP), c-IAP-1, Bcl-2 and Bax. The differentiation of BMDM is associated with a steady and gradual increase in the levels of c-fms, XIAP, c-IAP-1, Bcl-2 and Bax, reaching maximal levels by day 7. However, the levels of caspase-3 and caspase-9 stayed essentially unchanged even after prolonged incubation (more than 10 days) with M-CSF. Unlike bone marrow precursor cells, mature BMDM (day 7Ő10) were resistant to apoptosis induced by M-CSF depletion, which includes the activation of caspase-3 and caspase-9 and the degradation of XIAP, Bcl-2 and Bax proteins in the process. Treatment of day 7 BMDM with XIAP anti-sense oligonucleotides (oligos), but not sense oligos, partly abolished their resistance to apoptosis. By using a gel-shift assay and a specific nuclear factor κB (NF-κB) inhibitor, we demonstrated that NF-κB activity is responsible for the up-regulation of XIAP in M-CSF-treated macrophages. In addition, treatment of starved macrophages with M-CSF induced a rapid phosphorylation of Akt kinase before the activation of NF-κB. Our results showed that XIAP is one of the anti-apoptotic regulators that confer resistance on mature macrophages by M-CSF.

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Structure-based design, synthesis, and evaluation of the biological activity of novel phosphoroorganic small molecule IAP antagonists

Investigational New Drugs ◽

10.1007/s10637-020-00923-4 ◽

2020 ◽

Vol 38 (5) ◽

pp. 1350-1364 ◽

Cited By ~ 1

Author(s):

Agnieszka Łupicka-Słowik ◽

Mateusz Psurski ◽

Renata Grzywa ◽

Monika Cuprych ◽

Jarosław Ciekot ◽

...

Keyword(s):

Cancer Cell Line ◽

Biochemical Properties ◽

Inhibitor Of Apoptosis ◽

Binding Motif ◽

Inhibitory Influence ◽

Design Synthesis ◽

Inhibitor Of Apoptosis Protein ◽

Design And Synthesis ◽

Apoptosis Protein ◽

Fluorescence Polarization Assay

Summary One of the strategies employed by novel anticancer therapies is to put the process of apoptosis back on track by blocking the interaction between inhibitor of apoptosis proteins (IAPs) and caspases. The activity of caspases is modulated by the caspases themselves in a caspase/procaspase proteolytic cascade and by their interaction with IAPs. Caspases can be released from the inhibitory influence of IAPs by proapoptotic proteins such as secondary mitochondrial activator of caspases (Smac) that share an IAP binding motif (IBM). The main purpose of the present study was the design and synthesis of phosphorus-based peptidyl antagonists of IAPs that mimic the endogenous Smac protein, which blocks the interaction between IAPs and caspases. Based on the structure of the IAP antagonist and recently reported thiadiazole derivatives, we designed and evaluated the biochemical properties of a series of phosphonic peptides bearing the N-Me-Ala-Val/Chg-Pro-OH motif (Chg: cyclohexylglycine). The ability of the obtained compounds to interact with the binding groove of the X-linked inhibitor of apoptosis protein baculovirus inhibitor of apoptosis protein repeat (XIAP BIR3) domain was examined by a fluorescence polarization assay, while their potential to induce autoubiquitination followed by proteasomal degradation of cellular IAP1 was examined using the MDA-MB-231 breast cancer cell line. The highest potency against BIR3 was observed among peptides containing C-terminal phosphonic phenylalanine analogs, which displayed nanomolar Ki values. Their antiproliferative potential as well as their proapoptotic action, manifested by an increase in caspase-3 activity, was examined using various cell lines.

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