PARP inhibition enhances tumor cell–intrinsic immunity in ERCC1-deficient non–small cell lung cancer
Roman M. Chabanon, … , Christopher J. Lord, Sophie Postel-Vinay
Roman M. Chabanon, … , Christopher J. Lord, Sophie Postel-Vinay
Published December 27, 2018
Citation Information: J Clin Invest. 2019;129(3):1211-1228. https://doi.org/10.1172/JCI123319.
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Research Article Oncology

PARP inhibition enhances tumor cell–intrinsic immunity in ERCC1-deficient non–small cell lung cancer

Abstract

The cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) pathway detects cytosolic DNA to activate innate immune responses. Poly(ADP-ribose) polymerase inhibitors (PARPi) selectively target cancer cells with DNA repair deficiencies such as those caused by BRCA1 mutations or ERCC1 defects. Using isogenic cell lines and patient-derived samples, we showed that ERCC1-defective non–small cell lung cancer (NSCLC) cells exhibit an enhanced type I IFN transcriptomic signature and that low ERCC1 expression correlates with increased lymphocytic infiltration. We demonstrated that clinical PARPi, including olaparib and rucaparib, have cell-autonomous immunomodulatory properties in ERCC1-defective NSCLC and BRCA1-defective triple-negative breast cancer (TNBC) cells. Mechanistically, PARPi generated cytoplasmic chromatin fragments with characteristics of micronuclei; these were found to activate cGAS/STING, downstream type I IFN signaling, and CCL5 secretion. Importantly, these effects were suppressed in PARP1-null TNBC cells, suggesting that this phenotype resulted from an on-target effect of PARPi on PARP1. PARPi also potentiated IFN-γ–induced PD-L1 expression in NSCLC cell lines and in fresh patient tumor cells; this effect was enhanced in ERCC1-deficient contexts. Our data provide a preclinical rationale for using PARPi as immunomodulatory agents in appropriately molecularly selected populations.

Authors

Roman M. Chabanon, Gareth Muirhead, Dragomir B. Krastev, Julien Adam, Daphné Morel, Marlène Garrido, Andrew Lamb, Clémence Hénon, Nicolas Dorvault, Mathieu Rouanne, Rebecca Marlow, Ilirjana Bajrami, Marta Llorca Cardeñosa, Asha Konde, Benjamin Besse, Alan Ashworth, Stephen J. Pettitt, Syed Haider, Aurélien Marabelle, Andrew N.J. Tutt, Jean-Charles Soria, Christopher J. Lord, Sophie Postel-Vinay

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Figure 7

PARPi induce secretion of the chemotactic chemokine CCL5 in a cGAS/STING-dependent manner, and activate type I IFN signaling.

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PARPi induce secretion of the chemotactic chemokine CCL5 in a cGAS/STING...
(A) RT-qPCR analysis of RNA isolated from Ola-exposed A549-ERCC1WT/WT and A549-ERCC1–/– cells, in the presence or absence of cGAS/STING silencing by siRNA. Cells were transfected with siCTRL or sicGAS + siSTING and treated for 72 hours with DMSO or a range of doses of Ola (μM). CCL5 mRNAs were analyzed relative to GAPDH. Box-and-whisker plots show arbitrary units of gene expression, normalized to DMSO-treated control. Boxes indicate median and lower and upper quartiles; whiskers indicate the 5th to 95th percentile range; n = 12, Kruskal-Wallis test and post hoc Dunn’s test, relative to DMSO control. (B) RT-qPCR analysis of RNA isolated from A549-ERCC1WT/WT and A549-ERCC1–/– cells, in the presence or absence of cGAS/STING silencing by siRNA. Cells were transfected with siCTRL or sicGAS + siSTING. CCL5 mRNAs were analyzed relative to GAPDH. Shown are arbitrary units of gene expression, normalized to A549-ERCC1WT/WT DMSO-treated control. Mean ± SD, n = 4, 2-way ANOVA. (C) Quantitative analysis of CCL5 secretion in A549-ERCC1 isogenic cell supernatants upon Ola exposure, in the presence or absence of cGAS/STING silencing by siRNA. Cells were transfected with siCTRL or sicGAS + siSTING and treated for 72 hours with DMSO or a dose range of Ola (μM). Supernatants were collected and analyzed by ELISA for detection of CCL5. Box-and-whisker plots show CCL5 concentrations. Boxes indicate median and lower and upper quartiles; whiskers indicate the 5th to 95th percentile range; n = 4, Kruskal-Wallis test and post hoc Dunn’s test, relative to DMSO control. (D and E) GSEA of the REACTOME pathway “IFN-α/β signaling” in talazoparib- (Talazo-) versus DMSO-treated A549-ERCC1WT/WT cells (D) or A549-ERCC1–/– cells (E). A heatmap showing the genes of the pathway is shown below. n = 3; heatmap scale is a Z score. Purple, significantly DEGs with FDR < 0.05 and |LFC| > 1; green, significantly DEGs with FDR < 0.05 and |LFC| > 0.58; gray, nonsignificantly DEGs.*P < 0.05, **P < 0.01, ***P < 0.001.