Overexpression of PrPc triggers caspase 3 activation: potentiation by proteasome inhibitors and blockade by anti-PrP antibodies.
We examined the influence of cellular prion protein (PrPc) in the control of cell death in stably transfected HEK293 cell line and in the PrPc-inducible Rov9 cells. PrPc expression in stably transfected HEK293 human cells did not modify basal apoptotic tonus but drastically potentiated staurosporine-stimulated cellular toxicity and DNA fragmentation as well as caspase 3-like activity and immunoreactivity. An identical staurosporine-induced caspase 3 activation was observed after doxycycline in the PrPc-inducible Rov9 cell line. Interestingly, proteasome inhibitors increase PrPc-like immunoreactivity and unmasked a basal caspase 3 activation. Conversely, we show that anti-PrPc antibodies sequestrate PrPc at the cell surface and drastically lower PrPc-dependent caspase activation. We suggest that intracellular PrPc could sensitize human cells to pro-apoptotic phenotype and that blockade of PrPc internalization could be a track to prevent intracellular toxicity associated with PrPc overexpression.
Paitel
E
E
IPMC of CNRS, UMR6097, Valbonne, France INRA, Jouy en Josas, France CEA/Saclay, Gif sur Yvette, France.
Alves da Costa
C
C
Vilette
D
D
Grassi
J
J
Checler
F
F
D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003546:Cysteine Endopeptidases; D053938:DNA Fragmentation; D004318:Doxycycline / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D051379:Mice; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors*; D018621:PrPC Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D046988:Proteasome Endopeptidase Complex; D012756:Sheep; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection
D000906:Antibodies; D004791:Enzyme Inhibitors; D009097:Multienzyme Complexes; D018621:PrPC Proteins; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D019311:Staurosporine; D004318:Doxycycline