PT  - JOURNAL ARTICLE
AU  - Liya Ding
AU  - Qiwei Wang
AU  - Antons Martincuks
AU  - Michael J Kearns
AU  - Tao Jiang
AU  - Ziying Lin
AU  - Xin Cheng
AU  - Changli Qian
AU  - Shaozhen Xie
AU  - Hye-Jung Kim
AU  - Inga-Maria Launonen
AU  - Anniina Färkkilä
AU  - Thomas M Roberts
AU  - Gordon J Freeman
AU  - Joyce F Liu
AU  - Panagiotis A Konstantinopoulos
AU  - Ursula Matulonis
AU  - Hua Yu
AU  - Jean J Zhao
TI  - STING agonism overcomes STAT3-mediated immunosuppression and adaptive resistance to PARP inhibition in ovarian cancer
AID  - 10.1136/jitc-2022-005627
DP  - 2023 Jan 01
TA  - Journal for ImmunoTherapy of Cancer
PG  - e005627
VI  - 11
IP  - 1
4099  - http://jitc.bmj.com/content/11/1/e005627.short
4100  - http://jitc.bmj.com/content/11/1/e005627.full
SO  - J Immunother Cancer2023 Jan 01; 11
AB  - Background Poly (ADP-ribose) polymerase (PARP) inhibition (PARPi) has demonstrated potent therapeutic efficacy in patients with BRCA-mutant ovarian cancer. However, acquired resistance to PARPi remains a major challenge in the clinic.Methods PARPi-resistant ovarian cancer mouse models were generated by long-term treatment of olaparib in syngeneic Brca1-deficient ovarian tumors. Signal transducer and activator of transcription 3 (STAT3)-mediated immunosuppression was investigated in vitro by co-culture experiments and in vivo by analysis of immune cells in the tumor microenvironment (TME) of human and mouse PARPi-resistant tumors. Whole genome transcriptome analysis was performed to assess the antitumor immunomodulatory effect of STING (stimulator of interferon genes) agonists on myeloid cells in the TME of PARPi-resistant ovarian tumors. A STING agonist was used to overcome STAT3-mediated immunosuppression and acquired PARPi resistance in syngeneic and patient-derived xenografts models of ovarian cancer.Results In this study, we uncover an adaptive resistance mechanism to PARP inhibition mediated by tumor-associated macrophages (TAMs) in the TME. Markedly increased populations of protumor macrophages are found in BRCA-deficient ovarian tumors that rendered resistance to PARPi in both murine models and patients. Mechanistically, PARP inhibition elevates the STAT3 signaling pathway in tumor cells, which in turn promotes protumor polarization of TAMs. STAT3 ablation in tumor cells mitigates polarization of protumor macrophages and increases tumor-infiltrating T cells on PARP inhibition. These findings are corroborated in patient-derived, PARPi-resistant BRCA1-mutant ovarian tumors. Importantly, STING agonists reshape the immunosuppressive TME by reprogramming myeloid cells and overcome the TME-dependent adaptive resistance to PARPi in ovarian cancer. This effect is further enhanced by addition of the programmed cell death protein-1 blockade.Conclusions We elucidate an adaptive immunosuppression mechanism rendering resistance to PARPi in BRCA1-mutant ovarian tumors. This is mediated by enrichment of protumor TAMs propelled by PARPi-induced STAT3 activation in tumor cells. We also provide a new strategy to reshape the immunosuppressive TME with STING agonists and overcome PARPi resistance in ovarian cancer.Data are available in a public, open access repository. Data are available upon reasonable request.