Smac mimetic compounds potentiate interleukin-1beta-mediated cell death.
Smac mimetic compounds (SMCs) potentiate TNFα-mediated cancer cell death by targeting the inhibitor of apoptosis (IAP) proteins. In addition to TNFα, the tumor microenvironment is exposed to a number of pro-inflammatory cytokines, including IL-1β. Here, we investigated the potential impact of IL-1β on SMC-mediated death of cancer cells. Synergy was seen in a subset of a diverse panel of 21 cancer cell lines to the combination of SMC and IL-1β treatment, which required IL-1β-induced activation of the NF-κB pathway. Elevated NF-κB activity resulted in the production of TNFα, which led to apoptosis dependent on caspase-8 and RIP1. In addition, concurrent silencing of cIAP1, cIAP2, and X-linked IAP by siRNA was most effective for triggering IL-1β-mediated cell death. Importantly, SMC-resistant cells that produced TNFα in response to IL-1β treatment were converted to an SMC-sensitive phenotype by c-FLIP knockdown. Reciprocally, ectopic expression of c-FLIP blocked cell death caused by combined SMC and IL-1β treatment in sensitive cancer cells. Together, our study indicates that a positive feed-forward loop by pro-inflammatory cytokines can be exploited by SMCs to induce apoptosis in cancer cells.
Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario K1H 8L1, Canada.
Herman H
HH
Cheung
Shawn T
ST
Beug
Martine
M
St Jean
Audrey
A
Brewster
N Lynn
NL
Kelly
Shaomeng
S
Wang
Robert G
RG
Korneluk
D000480:Alkynes / Q000819:agonists / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000819:agonists / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics / Q000378:metabolism; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D004151:Dipeptides / Q000819:agonists / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D055785:Gene Knockdown Techniques; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D053583:Interleukin-1beta / Q000819:agonists / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D057786:Peptidomimetics / Q000819:agonists / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
C535053:AEG 40730; D000480:Alkynes; D000970:Antineoplastic Agents; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506387:Cflar protein, mouse; D004151:Dipeptides; D051034:Inhibitor of Apoptosis Proteins; D053583:Interleukin-1beta; D016328:NF-kappa B; D057786:Peptidomimetics; D014409:Tumor Necrosis Factor-alpha; C494832:BIRC3 protein, human; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D044767:Ubiquitin-Protein Ligases; C505530:CASP8 protein, human; C505526:Casp8 protein, mouse; D053181:Caspase 8