Che-1 activates XIAP expression in response to DNA damage.
X-linked inhibitor of apoptosis protein (XIAP) is a member of the inhibitor of apoptosis proteins family that selectively binds and inhibits caspase-3, -7 and -9. As such, XIAP is an extremely potent suppressor of apoptosis and an attractive target for cancer treatment. Che-1 is an antiapoptotic agent involved in the control of gene transcription and cell proliferation. Recently, we showed that the checkpoint kinases ATM/ATR and checkpoint kinase 2 physically and functionally interact with Che-1 and promote its phosphorylation and accumulation in response to DNA damage. These Che-1 modifications induce transcription of p53, and Che-1 depletion strongly sensitizes tumor cells to anticancer drugs. Here we show that Che-1 activates XIAP expression in response to DNA damage. This effect is mediated by Che-1 phosphorylation and requires NF-kappaB. Notably, we found that XIAP expression is necessary for antiapoptotic activity of Che-1 and that in vivo downregulation of Che-1 by small interference RNA strongly enhanced the cytotoxicity of anticancer drugs.
Laboratory B, Department of Therapeutic Programs Development, Regina Elena Cancer Institute, Rome, Italy.
T
T
Bruno
S
S
Iezzi
F
F
De Nicola
M
M
Di Padova
A
A
Desantis
M
M
Scarsella
M G
MG
Di Certo
C
C
Leonetti
A
A
Floridi
C
C
Passananti
M
M
Fanciulli
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D004249:DNA Damage; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000378:metabolism; D041681:NIH 3T3 Cells; D034622:RNA Interference; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation; D015854:Up-Regulation; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000096:biosynthesis* / Q000235:genetics
C402637:AATF protein, human; D051017:Apoptosis Regulatory Proteins; D016328:NF-kappa B; D012097:Repressor Proteins; D014157:Transcription Factors; D051636:X-Linked Inhibitor of Apoptosis Protein