Smac mimetic Birinapant induces apoptosis and enhances TRAIL potency in inflammatory breast cancer cells in an IAP-dependent and TNF-α-independent mechanism.

Allensworth, Jennifer L

Sauer, Scott J

Lyerly, H Kim

Morse, Michael A

Devi, Gayathri R

Netherlands

2016-07-08T19:33:36Z

2013-01

X-linked inhibitor of apoptosis protein (XIAP), the most potent mammalian caspase inhibitor, has been associated with acquired therapeutic resistance in inflammatory breast cancer (IBC), an aggressive subset of breast cancer with an extremely poor survival rate. The second mitochondria-derived activator of caspases (Smac) protein is a potent antagonist of IAP proteins and the basis for the development of Smac mimetic drugs. Here, we report for the first time that bivalent Smac mimetic Birinapant induces cell death as a single agent in TRAIL-insensitive SUM190 (ErbB2-overexpressing) cells and significantly increases potency of TRAIL-induced apoptosis in TRAIL-sensitive SUM149 (triple-negative, EGFR-activated) cells, two patient tumor-derived IBC models. Birinapant has high binding affinity (nM range) for cIAP1/2 and XIAP. Using isogenic SUM149- and SUM190-derived cells with differential XIAP expression (SUM149 wtXIAP, SUM190 shXIAP) and another bivalent Smac mimetic (GT13402) with high cIAP1/2 but low XIAP binding affinity (K (d) > 1 μM), we show that XIAP inhibition is necessary for increasing TRAIL potency. In contrast, single agent efficacy of Birinapant is due to pan-IAP antagonism. Birinapant caused rapid cIAP1 degradation, caspase activation, PARP cleavage, and NF-κB activation. A modest increase in TNF-α production was seen in SUM190 cells following Birinapant treatment, but no increase occurred in SUM149 cells. Exogenous TNF-α addition did not increase Birinapant efficacy. Neutralizing antibodies against TNF-α or TNFR1 knockdown did not reverse cell death. However, pan-caspase inhibitor Q-VD-OPh reversed Birinapant-mediated cell death. In addition, Birinapant in combination or as a single agent decreased colony formation and anchorage-independent growth potential of IBC cells. By demonstrating that Birinapant primes cancer cells for death in an IAP-dependent manner, these findings support the development of Smac mimetics for IBC treatment.

http://www.ncbi.nlm.nih.gov/pubmed/23225169

1573-7217

https://hdl.handle.net/10161/12454

eng

Springer Science and Business Media LLC

Breast Cancer Res Treat

10.1007/s10549-012-2352-6

Amino Acid Chloromethyl Ketones

Apoptosis

Caspase 8

Cell Line, Tumor

Dipeptides

Dose-Response Relationship, Drug

Gene Knockdown Techniques

Humans

Indoles

Inflammatory Breast Neoplasms

Inhibitor of Apoptosis Proteins

Intracellular Signaling Peptides and Proteins

Mitochondrial Proteins

Quinolines

Receptors, Tumor Necrosis Factor, Type I

TNF-Related Apoptosis-Inducing Ligand

Tumor Necrosis Factor-alpha

X-Linked Inhibitor of Apoptosis Protein

Smac mimetic Birinapant induces apoptosis and enhances TRAIL potency in inflammatory breast cancer cells in an IAP-dependent and TNF-α-independent mechanism.

Journal article

http://www.ncbi.nlm.nih.gov/pubmed/23225169

359

371

2

Basic Science Departments

Clinical Science Departments

Duke

Duke Cancer Institute

Global Health Institute

Immunology

Institutes and Centers

Institutes and Provost's Academic Units

Medicine

Medicine, Medical Oncology

Pathology

School of Medicine

Staff

Surgery

Surgery, Surgical Oncology Molecular Theraputics

Surgery, Surgical Sciences

University Institutes and Centers

Published

137