Mechanisms of pre-apoptotic calreticulin exposure in immunogenic cell death.
Dying tumour cells can elicit a potent anticancer immune response by exposing the calreticulin (CRT)/ERp57 complex on the cell surface before the cells manifest any signs of apoptosis. Here, we enumerate elements of the pathway that mediates pre-apoptotic CRT/ERp57 exposure in response to several immunogenic anticancer agents. Early activation of the endoplasmic reticulum (ER)-sessile kinase PERK leads to phosphorylation of the translation initiation factor eIF2alpha, followed by partial activation of caspase-8 (but not caspase-3), caspase-8-mediated cleavage of the ER protein BAP31 and conformational activation of Bax and Bak. Finally, a pool of CRT that has transited the Golgi apparatus is secreted by SNARE-dependent exocytosis. Knock-in mutation of eIF2alpha (to make it non-phosphorylatable) or BAP31 (to render it uncleavable), depletion of PERK, caspase-8, BAP31, Bax, Bak or SNAREs abolished CRT/ERp57 exposure induced by anthracyclines, oxaliplatin and ultraviolet C light. Depletion of PERK, caspase-8 or SNAREs had no effect on cell death induced by anthracyclines, yet abolished the immunogenicity of cell death, which could be restored by absorbing recombinant CRT to the cell surface.
Panaretakis
Theocharis
T
INSERM, Unit 848, Villejuif, France.
Kepp
Oliver
O
Brockmeier
Ulf
U
Tesniere
Antoine
A
Bjorklund
Ann-Charlotte
AC
Chapman
Daniel C
DC
Durchschlag
Michael
M
Joza
Nicholas
N
Pierron
Gérard
G
van Endert
Peter
P
Yuan
Junying
J
Zitvogel
Laurence
L
Madeo
Frank
F
Williams
David B
DB
Kroemer
Guido
G
D018943:Anthracyclines / Q000276:immunology / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis; D037282:Calreticulin / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D016923:Cell Death / Q000276:immunology*; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D005089:Exocytosis; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D009944:Organoplatinum Compounds / Q000276:immunology / Q000494:pharmacology; D000077150:Oxaliplatin; D010766:Phosphorylation; D050600:SNARE Proteins / Q000378:metabolism; D014466:Ultraviolet Rays; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D019892:eIF-2 Kinase / Q000378:metabolism
D018943:Anthracyclines; D000970:Antineoplastic Agents; D037282:Calreticulin; D053148:Caspase 3; D053181:Caspase 8; D015852:Eukaryotic Initiation Factor-2; D008565:Membrane Proteins; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D050600:SNARE Proteins; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D019892:eIF-2 Kinase; C494772:BAK1 protein, human; C494826:BAX protein, human; C091247:BCAP31 protein, human