RESUMEN
Peptido-mimetic inhibitor of apoptosis protein (IAP) antagonists (Smac mimetics (SMs)) can kill tumour cells by depleting endogenous IAPs and thereby inducing tumour necrosis factor (TNF) production. We found that interferon-γ (IFNγ) synergises with SMs to kill cancer cells independently of TNF- and other cell death receptor signalling pathways. Surprisingly, CRISPR/Cas9 HT29 cells doubly deficient for caspase-8 and the necroptotic pathway mediators RIPK3 or MLKL were still sensitive to IFNγ/SM-induced killing. Triple CRISPR/Cas9-knockout HT29 cells lacking caspase-10 in addition to caspase-8 and RIPK3 or MLKL were resistant to IFNγ/SM killing. Caspase-8 and RIPK1 deficiency was, however, sufficient to protect cells from IFNγ/SM-induced cell death, implying a role for RIPK1 in the activation of caspase-10. These data show that RIPK1 and caspase-10 mediate cell death in HT29 cells when caspase-8-mediated apoptosis and necroptosis are blocked and help to clarify how SMs operate as chemotherapeutic agents.
Asunto(s)
Apoptosis/efectos de los fármacos , Caspasa 10/metabolismo , Proteínas Inhibidoras de la Apoptosis/metabolismo , Interferón gamma/farmacología , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Animales , Sistemas CRISPR-Cas/genética , Caspasa 10/química , Caspasa 10/genética , Caspasa 8/química , Caspasa 8/genética , Caspasa 8/metabolismo , Inhibidores de Caspasas/farmacología , Línea Celular , Citocina TWEAK/farmacología , Sinergismo Farmacológico , Células HT29 , Humanos , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Interferón gamma/genética , Interferón gamma/metabolismo , Ratones , Ratones Noqueados , Ácidos Pentanoicos/farmacología , Proteínas Quinasas/deficiencia , Proteínas Quinasas/metabolismo , Proteína Serina-Treonina Quinasas de Interacción con Receptores/deficiencia , Proteína Serina-Treonina Quinasas de Interacción con Receptores/genética , Receptores Tipo I de Factores de Necrosis Tumoral/deficiencia , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/farmacologíaRESUMEN
Birinapant is a smac-mimetic (SM) in clinical trials for treating cancer. SM antagonize inhibitor of apoptosis (IAP) proteins and simultaneously induce tumor necrosis factor (TNF) secretion to render cancers sensitive to TNF-induced killing. To enhance SM efficacy, we screened kinase inhibitors for their ability to increase TNF production of SM-treated cells. We showed that p38 inhibitors increased TNF induced by SM. Unexpectedly, even though p38 is required for Toll-like receptors to induce TNF, loss of p38 or its downstream kinase MK2 increased induction of TNF by SM. Hence, we show that the p38/MK2 axis can inhibit or promote TNF production, depending on the stimulus. Importantly, clinical p38 inhibitors overcame resistance of primary acute myeloid leukemia to birinapant.
