Type

Journal Article

Authors

M Rehm
J H M Prehn
M Devocelle
M E Delgado
M L Würstle
J A Rauen
H Düssmann
E Passante
M A Laussmann

Subjects

Biochemistry

Topics
hela cells mice mutant strains flow cytometry boronic acids genetics bortezomib metabolism pyrazines xiap protein human proteasome endopeptidase complex atg5 protein human fas associated death domain protein peptide hydrolases fluorescence resonance energy transfer autophagy caspase 3 physiology microtubule associated proteins pharmacology animals apoptosis microscopy fluorescence devdase proto oncogene proteins c bcl 2 immunoblotting fadd protein human caspase 7 mice drug effects humans caspase 8 x linked inhibitor of apoptosis protein antagonists inhibitors

Proteasome inhibition can induce an autophagy-dependent apical activation of caspase-8. (2011)

Abstract Antiapoptotic Bcl-2 family proteins are often highly expressed in chemotherapy-resistant cancers and impair mitochondrial outer membrane permeabilisation (MOMP), an important requirement for caspase activation via the intrinsic apoptosis pathway. Interestingly, although Bcl-2 overexpression in HeLa cervical cancer cells abrogated caspase processing in response to intrinsic apoptosis induction by staurosporine, tunicamycin or etoposide, residual caspase processing was observed following proteasome inhibition by bortezomib ([(1R)-3-methyl-1-({(2S)-3-phenyl-2-[(pyrazin-2-ylcarbonyl)amino]propanoyl}amino)butyl]boronic acid), epoxomicin (N-acetyl-N-methyl-lisoleucyl-L-isoleucyl-N-[(1S)-3-methyl-1-[[(2R)-2-methyloxiranyl]carbonyl]butyl]-L-threoninamide) or MG-132 (N-(benzyloxycarbonyl)leucinylleucinylleucinal). Similar responses were found in Bcl-2-overexpressing H460 NSCLC cells and Bax/Bak-deficient mouse embyronic fibroblasts. Mild caspase processing resulted in low DEVDase activities, which were MOMP independent and persisted for long periods without evoking immediate cell death. Surprisingly, depletion of caspase-3 and experiments in caspase-7-depleted MCF-7-Bcl-2 cells indicated that the DEVDase activity did not originate from effector caspases. Instead, Fas-associated death domain (FADD)-dependent caspase-8 activation was the major contributor to the slow, incomplete substrate cleavage. Caspase-8 activation was independent of death ligands, but required the induction of autophagy and the presence of Atg5. Depletion of XIAP or addition of XIAP-antagonising peptides resulted in a switch towards efficient apoptosis execution, suggesting that the requirement for MOMP was bypassed by activating the caspase-8/caspase-3 axis. Combination treatments of proteasome inhibitors and XIAP antagonists therefore represent a promising strategy to eliminate highly resistant cancer cells, which overexpress antiapoptotic Bcl-2 family members.
Collections Ireland -> Royal College of Surgeons in Ireland -> PubMed

Full list of authors on original publication

M Rehm, J H M Prehn, M Devocelle, M E Delgado, M L Würstle, J A Rauen, H Düssmann, E Passante, M A Laussmann

Experts in our system

1
Markus Rehm
Royal College of Surgeons in Ireland
Total Publications: 55
 
2
Jochen H M Prehn
Royal College of Surgeons in Ireland
Total Publications: 206
 
3
Marc Devocelle
Royal College of Surgeons in Ireland
Total Publications: 65
 
4
Maximilian L Würstle
Royal College of Surgeons in Ireland
Total Publications: 13
 
5
Heiko Düssmann
Royal College of Surgeons in Ireland
Total Publications: 45
 
6
E Passante
Royal College of Surgeons in Ireland
Total Publications: 6