Oncogene-dependent regulation of caspase activation by p53 protein in a cell-free system.
The mechanism by which p53 modulates apoptosis in cancer therapy is incompletely understood. Here, cell-free extracts from irradiated tumor cells are described in which endogenous p53 protein is shown to participate in caspase activation. This apoptotic activity is also oncogene-dependent, but independent of transcription in general or the presence of Bax or cytochrome c. A general use for this system is as a cell-free screen for apoptosis modulators. In this way, profound effects of protein kinase A were identified and corroborated in vivo by the protection conferred by cAMP against diverse triggers of p53-dependent apoptosis. This system provides direct biochemical evidence that p53 protein can transduce apoptotic signals through protein-protein interactions and reveals a modulator kinase pathway capable of regulating p53-dependent caspase activation.
Department of Pediatric Oncology, Dana-Farber Cancer Institute and Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
H F
HF
Ding
G
G
McGill
S
S
Rowan
C
C
Schmaltz
A
A
Shimamura
D E
DE
Fisher
D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism*; D002461:Cell Line, Transformed / Q000528:radiation effects; D002471:Cell Transformation, Neoplastic; D002474:Cell-Free System; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004794:Enzyme Repression; D005720:Gamma Rays; D051379:Mice; D009857:Oncogenes; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051381:Rats; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; C494828:Bax protein, rat; D003574:Cytochrome c Group; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D000266:Adenylyl Imidodiphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D020169:Caspases