ATM and MET kinases are synthetic lethal with nongenotoxic activation of p53.

Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado, USA.
Nature Chemical Biology (Impact Factor: 12.95). 06/2012; 8(7):646-54. DOI: 10.1038/nchembio.965
Source: PubMed

ABSTRACT The p53 tumor suppressor orchestrates alternative stress responses including cell cycle arrest and apoptosis, but the mechanisms defining cell fate upon p53 activation are poorly understood. Several small-molecule activators of p53 have been developed, including Nutlin-3, but their therapeutic potential is limited by the fact that they induce reversible cell cycle arrest in most cancer cell types. We report here the results of a genome-wide short hairpin RNA screen for genes that are lethal in combination with p53 activation by Nutlin-3, which showed that the ATM and MET kinases govern cell fate choice upon p53 activation. Genetic or pharmacological interference with ATM or MET activity converts the cellular response from cell cycle arrest into apoptosis in diverse cancer cell types without affecting expression of key p53 target genes. ATM and MET inhibitors also enable Nutlin-3 to kill tumor spheroids. These results identify new pathways controlling the cellular response to p53 activation and aid in the design of p53-based therapies.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The p53 transcription factor participates in diverse cellular responses to stress, including cell-cycle arrest, apoptosis, senescence, and autophagy. The molecular mechanisms defining the ultimate outcome of p53 activation remain poorly characterized. We performed a genome-wide genetic screen in human cells to identify pathway-specific coregulators of the p53 target gene CDKN1A (p21), an inhibitor of cell-cycle progression, versus BBC3 (PUMA), a key mediator of apoptosis. Our screen identified numerous factors whose depletion creates an imbalance in the p21:PUMA ratio upon p53 activation. The transcription factor TCF3, also known as E2A, drives p21 expression while repressing PUMA across cancer cell types of multiple origins. Accordingly, TCF3/E2A depletion impairs the cell-cycle-arrest response and promotes apoptosis upon p53 activation by chemotherapeutic agents. In contrast, TRIAP1 is a specific repressor of p21 whose depletion slows down cell-cycle progression. Our results reveal strategies for driving cells toward specific p53-dependent responses.
    Cell Reports 05/2013; · 7.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Protein kinases play important roles in regulating signal transduction in eukaryotic cells. Due to evolutionary conserved binding sites in the catalytic domain of the kinases, most inhibitors that target these sites promiscuously inhibit multiple kinases. Quantitative analysis can reveal complex and unexpected interactions between protein kinases and kinase inhibitors, providing opportunities for identifying multi-targeted inhibitors of specific diverse kinases for drug repurposing and development. We have developed K-Map---a novel and user-friendly web-based program that systematically connects a set of query kinases to kinase inhibitors based on quantitative profiles of the kinase inhibitor activities. Users can use K-Map to find kinase inhibitors for a set of query kinases (obtained from high-throughput 'omics' experiments) or to reveal new interactions between kinases and kinase inhibitors for rational drug combination studies.Availability and implementation: K-Map has been implemented in python scripting language and the website is freely available at:
    Human genomics 09/2013; 7(1):20.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The p53 transcription factor is a potent suppressor of tumor growth. We report here an analysis of its direct transcriptional program using Global Run-On sequencing (GRO-seq). Shortly after MDM2 inhibition by Nutlin-3, low levels of p53 rapidly activate ∼200 genes, most of them not previously established as direct targets. This immediate response involves all canonical p53 effector pathways, including apoptosis. Comparative global analysis of RNA synthesis vs steady state levels revealed that microarray profiling fails to identify low abundance transcripts directly activated by p53. Interestingly, p53 represses a subset of its activation targets before MDM2 inhibition. GRO-seq uncovered a plethora of gene-specific regulatory features affecting key survival and apoptotic genes within the p53 network. p53 regulates hundreds of enhancer-derived RNAs. Strikingly, direct p53 targets harbor pre-activated enhancers highly transcribed in p53 null cells. Altogether, these results enable the study of many uncharacterized p53 target genes and unexpected regulatory mechanisms.DOI:
    eLife Sciences 05/2014; 3:e02200.

Full-text (2 Sources)

Available from
May 26, 2014