Sarah Wang, K. Sun, Yonghong Xiao
Jul 1, 2018
Citations
1
Influential Citations
8
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Quality indicators
Journal
Immunology
Abstract
Niraparib is an orally available and selective poly(ADP-ribose) polymerase (PARP)-1/-2 inhibitor approved for maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to platinum-based chemotherapy. PARP inhibition may enhance the immune response in tumors treated with anti-PD-1 therapy via generation of cytosolic DNA that activates T cells through the stimulator of interferon gene (STING) pathway, rendering tumors immunologically “hot” with an increase in infiltrating lymphocytes. In this study, we explored the responses and mechanism of action of niraparib and anti-PD-1/anti-PD-L1 combination therapy in preclinical models. Out of a cohort of 14 immune-competent mouse tumor models, the combination treatment demonstrated enhanced anti-tumor activity in eight tumor models derived from BRCA-proficient and BRCA-deficient genetic backgrounds. Substantial increases compared to monotherapies in anti-tumor activity was observed in 5 models, indicative of synergy between niraparib and anti-PD-1/anti-PD-L1 therapy. The combination triggered durable responses that were coincident with induction of immune memories in a BRCA-deficient ovarian syngeneic model. Mechanistically, niraparib treatment increased the number of infiltrating CD8+ and CD4+ cells within the intratumoral region. The enhanced immune cell infiltration was accompanied by elevated interferon-stimulated gene expression. Pathway analyses using transcriptome profiling identified interferon response gene signatures as the significantly differentially-upregulated gene sets following niraparib treatment. Consistently, niraparib treatment activated the STING pathway in vitro in BRCA-deficient MDA-MB-436 human triple negative breast cancer cells. STING pathway markers including p-STING(Ser366), p-TBK1(Ser172) and p-NFκB p65 were elevated following niraparib treatment and was accompanied by an increase in IFNB mRNA expression. In summary, our data suggested that niraparib treatment in combination with anti-PD-1/anti-PD-L1 therapy enhanced immune cell infiltration, interferon-stimulated gene expression and tumor responses. Citation Format: Sarah Wang, Kaiming Sun, Yonghong Xiao, Bin Feng, Keith Mikule, Sridhar Ramaswamy, Jeffrey Hanke, Jing Wang. Evaluation of niraparib in combination with anti-PD1/anti-PD-L1 in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1724.