Esfandiari, A;
Hawthorne, TA;
Nakjang, S;
Lunec, J;
(2016)
Chemical Inhibition of Wild-Type p53-Induced Phosphatase 1 (WIP1/PPM1D) by GSK2830371 Potentiates the Sensitivity to MDM2 Inhibitors in a p53-Dependent Manner.
Molecular Cancer Therapeutics
, 15
(3)
pp. 379-391.
10.1158/1535-7163.MCT-15-0651.
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Abstract
Sensitivity to MDM2 inhibitors is widely different among responsive TP53 wild-type cell lines and tumors. Understanding the determinants of MDM2 inhibitor sensitivity is pertinent for their optimal clinical application. Wild-type p53-inducible phosphatase-1 (WIP1) encoded by PPM1D, is activated, gained/amplified in a range of TP53 wild-type malignancies, and is involved in p53 stress response homeostasis. We investigated cellular growth/proliferation of TP53 wild-type and matched mutant/null cell line pairs, differing in PPM1D genetic status, in response to Nutlin-3/RG7388 ± a highly selective WIP1 inhibitor, GSK2830371. We also assessed the effects of GSK2830371 on MDM2 inhibitor-induced p53Ser15 phosphorylation, p53-mediated global transcriptional activity, and apoptosis. The investigated cell line pairs were relatively insensitive to single-agent GSK2830371. However, a non–growth-inhibitory dose of GSK2830371 markedly potentiated the response to MDM2 inhibitors in TP53 wild-type cell lines, most notably in those harboring PPM1D-activating mutations or copy number gain (up to 5.8-fold decrease in GI50). Potentiation also correlated with significant increase in MDM2 inhibitor–induced cell death endpoints that were preceded by a marked increase in a WIP1 negatively regulated substrate, phosphorylated p53Ser15, known to increase p53 transcriptional activity. Microarray-based gene expression analysis showed that the combination treatment increases the subset of early RG7388-induced p53 transcriptional target genes. These findings demonstrate that potent and selective WIP1 inhibition potentiates the response to MDM2 inhibitors in TP53 wild-type cells, particularly those with PPM1D activation or gain, while highlighting the mechanistic importance of p53Ser15 and its potential use as a biomarker for response to this combination regimen. Mol Cancer Ther; 15(3); 379–91. ©2016 AACR.
| Type: | Article |
|---|---|
| Title: | Chemical Inhibition of Wild-Type p53-Induced Phosphatase 1 (WIP1/PPM1D) by GSK2830371 Potentiates the Sensitivity to MDM2 Inhibitors in a p53-Dependent Manner |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1158/1535-7163.MCT-15-0651 |
| Publisher version: | http://dx.doi.org/10.1158/1535-7163.MCT-15-0651 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Life Sciences & Biomedicine, Oncology, WIP1 PHOSPHATASE, DRUG-SENSITIVITY, PPM1D MUTATIONS, GENE-EXPRESSION, G1 CHECKPOINT, P53 PATHWAY, DNA-DAMAGE, CANCER, APOPTOSIS, PHOSPHORYLATION |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Cancer Institute UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Cancer Institute > Research Department of Oncology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10046502 |
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