Smac mimetic bypasses apoptosis resistance in FADD- or caspase-8-deficient cells by priming for tumor necrosis factor α-induced necroptosis.
Searching for new strategies to bypass apoptosis resistance, we investigated the potential of the Smac mimetic BV6 in Jurkat leukemia cells deficient in key molecules of the death receptor pathway. Here, we demonstrate for the first time that Smac mimetic primes apoptosis-resistant, FADD- or caspase-8-deficient leukemia cells for TNFα-induced necroptosis in a synergistic manner. In contrast to TNFα, Smac mimetic significantly enhances CD95-induced apoptosis in wild-type but not in FADD-deficient cells. Interestingly, Smac mimetic- and TNFα-mediated cell death occurs without characteristic features of apoptosis (i.e., caspase activation, DNA fragmentation) in FADD-deficient cells. By comparison, Smac mimetic and TNFα trigger activation of caspase-8, -9, and -3 and DNA fragmentation in wild-type cells. Consistently, the caspase inhibitor zVAD.fmk fails to block Smac mimetic- and TNFα-triggered cell death in FADD- or caspase-8-deficient cells, while it confers protection in wild-type cells. By comparison, necrostatin-1, an RIP1 kinase inhibitor, abolishes Smac mimetic- and TNFα-induced cell death in FADD- or caspase-8-deficient. Thus, Smac mimetic enhances TNFα-induced cell death in leukemia cells via two distinct pathways in a context-dependent manner: it primes apoptosis-resistant cells lacking FADD or caspase-8 to TNFα-induced, RIP1-dependent and caspase-independent necroptosis, whereas it sensitizes apoptosis-proficient cells to TNFα-mediated, caspase-dependent apoptosis. These findings have important implications for the therapeutic exploitation of necroptosis as an alternative cell death program to overcome apoptosis resistance.
University Children's Hospital, Ulm, Germany.
Bram
B
Laukens
Claudia
C
Jennewein
Barbara
B
Schenk
Nele
N
Vanlangenakker
Alexander
A
Schier
Silvia
S
Cristofanon
Kerry
K
Zobel
Kurt
K
Deshayes
Domagoj
D
Vucic
Irmela
I
Jeremias
Mathieu J M
MJ
Bertrand
Peter
P
Vandenabeele
Simone
S
Fulda
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D040761:Biomimetic Materials / Q000494:pharmacology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D053200:Fas-Associated Death Domain Protein / Q000172:deficiency / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D019169:Jurkat Cells; D008856:Microscopy, Fluorescence; D024101:Mitochondrial Proteins / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
C119724:AGFG1 protein, human; D051017:Apoptosis Regulatory Proteins; C412403:DIABLO protein, human; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D007093:Imidazoles; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D028861:Nuclear Pore Complex Proteins; D016601:RNA-Binding Proteins; D014409:Tumor Necrosis Factor-alpha; C507699:necrostatin-1; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9