How p53 differentially activates cell cycle arrest versus cell death remains poorly understood. Here, we demonstrate that upregulation of canonical pro-apoptotic p53 target genes in colon cancer cells imposes a critical dependence on the long splice form of the caspase-8 regulator FLIP (FLIP(L)), which we identify as a direct p53 transcriptional target. Inhibiting FLIP(L) expression with siRNA or Class-I HDAC inhibitors promotes apoptosis in response to p53 activation by the MDM2 inhibitor Nutlin-3A, which otherwise predominantly induces cell-cycle arrest. When FLIP(L) upregulation is inhibited, apoptosis is induced in response to p53 activation via a novel ligand-independent TRAIL-R2/caspase-8 complex, which, by activating BID, induces mitochondrial-mediated apoptosis. Notably, FLIP(L) depletion inhibits p53-induced expression of the cell cycle regulator p21 and enhances p53-mediated upregulation of PUMA, with the latter activating mitochondrial-mediated apoptosis in FLIP(L)-depleted, Nutlin-3A-treated cells lacking TRAIL-R2/caspase-8. Thus, we report two previously undescribed, novel FLIP(L)-dependent mechanisms that determine cell fate following p53 activation.
FLIP(L) determines p53 induced life or death
Andrea Lees,A. McIntyre,Fiammetta Falcone,N. Crawford,C. McCann,Gerard P. Quinn,Jamie Z. Roberts,T. Sessler,P. Gallagher,Gemma M. A. Gregg,K. McAllister,K. McLaughlin,W. Allen,C. Holohan,L. Egan,A. Ryan,Melissa Labonte-Wilson,P. Dunne,Mark Wappett,V. Coyle,P. Johnston,Emma M. Kerr,D. Longley,S. McDade
Published 2019 in bioRxiv
ABSTRACT
PUBLICATION RECORD
- Publication year
2019
- Venue
bioRxiv
- Publication date
2019-11-28
- Fields of study
Biology, Medicine, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
Showing 1-64 of 64 references · Page 1 of 1
CITED BY
- No citing papers are available for this paper.
Showing 0-0 of 0 citing papers · Page 1 of 1