Abstract B081: Type-I interferon (IFN-I) signaling following aurora kinase A (AURKA) inhibition is modulated by tumor p53 status
Authors: Nakatsuka Erika , Cunneen Brianna P. , Lei Yu Leo , McLean Karen 
Published: March 2024

Abstract
Introduction: Aurora kinase A (AURKA) is upregulated in ovarian cancer and many other solid tumors with its oncogenic effects mediated by multiple downstream mechanisms including the phosphorylation and subsequent inactivation of the p53 tumor suppressor. Given that p53 alterations are near-ubiquitous in high-grade serous carcinomas, we sought to determine the effect of p53 status on response to AURKA inhibition in the ID8 model system. Experimental Procedures: Murine ID8 ovarian cancer cells were generated by Katherine Roby. ID8/Trp53−/− cells were kindly obtained from Dr. Iain McNeish through Materials Transfer Agreement. Both the AURKA inhibitor alisertib and the pan-aurora kinase inhibitor tozasertib were commercially obtained, and ovarian cancer cells were treated with these drugs in vitro. Additionally, cells were treated with known Sting agonists of cGAMP, poly (dA:dT) or poly IC. RT-qPCR was performed to assess levels of IFN-I signaling transcripts, including Ifnb1, pan-Ifna, Isg15, and Mx1. Immunoblotting was performed to assess the activation of downstream signaling cascades, including total and phosphorylated Tbk1, total and phosphorylated Sting, and total and phosphorylated p65 subunit of NF-kB. In vivo experiments were performed in which ID8 or ID8/Trp53−/− cells were injected intraperitoneally into syngeneic C57BL/6 mice and animals were treated with the AURKA inhibitor alisertib or vehicle control. Tumor cells were collected at the time of animal sacrifice and both RT-PCR and immunoblotting were performed. Results: Both AURKA and pan-AURK inhibitor treatment resulted in the induction of DNA damage and apoptotic cell death. Furthermore, treatment resulted in the induction of type-I interferon (IFN-I) signaling. Additional pathway interrogation revealed that ID8/Trp53−/− cells demonstrate lower basal IFN-I gene expression levels than ID8 cells without Trp53 deletion. Following AURKA inhibition or pan-AURK inhibition, the induction of IFN-I signaling was more blunted in cells with Trp53 deletion as compared to parental ID8 cells, with the exception of maintained Ifna upregulation. Furthermore, immunoblotting revealed that while AURKA induced downstream IFN pathway activation in vitro as evidenced by phosphorylation of both Tbk1 and Sting in ID8 cells, such signaling was not observed in ID8/Trp53−/− cells. Using syngeneic animal models, induction of tumor cell IFN-I signaling was observed in vivo even in the setting of tumor cell Trp53 deletion, likely from the infiltrating immune cells. Conclusions: p53 status impacts IFN-I signaling both at baseline and following AURK inhibition in tumor cells. This finding has important implications for studying IFN-I signaling and immune modulation in preclinical immunocompetent mouse models and highlights the need for further interrogation of the impact of specific p53 alterations on therapeutic responses in high-grade serous carcinoma.
Citation Format: Erika Nakatsuka, Brianna P. Cunneen, Yu Leo Lei, Karen McLean. Type-I interferon (IFN-I) signaling following aurora kinase A (AURKA) inhibition is modulated by tumor p53 status [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr B081.