Abstract 5021: Preclinical evaluation of immunomodulatory effects of aurora kinase inhibition in HPV+ cancers

Abstract Human papillomavirus (HPV) is the causative agent of cervical cancer and some cancers of the penis, vulva, vagina, anus, and oropharynx. In an earlier study, we identified Aurora Kinase (AK) inhibitors from a large-scale drug screening as a unique class of reagents to induce selective apoptosis in HPV+ human tumor cells in vitro and in vivo (using HPV+ PDX mouse models). We tested the in vivo efficacy of alisertib, an Aurora Kinase A inhibitor, in an immunocompetent mouse model (mEER) for HPV+ oropharyngeal cancers. In preparation for this, we first tested 300 nM alisertib on 3 HPV+ murine cancer cell lines: TC-1, C3.43, and mEER for 48h. We observed that when compared to the vehicle (DMSO) control group, the level of phospho Aurora Kinase A was completely inhibited. Furthermore, in multiple HPV+ murine tumor cell lines we observed significant apoptosis as measured by annexin V 7-AAD staining along with higher cell surface expression of calreticulin (CRT), and high mobility group box 1 protein (HMGB1) which are markers for immunogenic cell death (ICD). Both CRT and HMGB1 serve as “eat me” signals that in turn trigger APC-mediated dead-cell antigen uptake, a crucial event for priming the responses from the innate immune system. In support of this, we observed that in a co-culture setting, the conditioned medium from alisertib-treated tumor cells increased the frequencies of CD8+ cells expressing GnzB as well as a significant decrease in the population of T regulatory cells (Tregs) (CD4+ FoxP3+). Additionally, we observed an increase in the innate immune natural killer cell subset. Future studies will explore the in vivo efficacy of Aurora Kinase inhibition along with immune checkpoint blockade and/or therapeutic vaccination. Our proposed research will have a positive impact because we will gain insight into the immune responses underlying the co-dependency of HPV+ cancers on Aurora kinase. Our research may lead to an increase in the rates of long-term, durable clinical responses or may allow for therapy de-escalation. Citation Format: Pragya Sinha, Soma Ghosh, Faye M. Johnson, Jagannadha K. Sastry. Preclinical evaluation of immunomodulatory effects of aurora kinase inhibition in HPV+ cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5021.