Abstract 936: HPV-related cancer model development and its application in the efficacy evaluation of a saRNA cancer vaccine

Abstract Cancer remains one of the most serious diseases threatening human health, influenced by many factors, such as genetic, physical, chemical and biological factors. Among various cancers, a special subtype is associated with viral infections. Globally, about 10% of all cancers are caused by viral infections including those from HPV, HBV, EBV and KSHV. After infection, these viruses manipulate the proliferation, metabolism, immunity and other life processes of the host cells through various mechanisms, resulting in malignant cell lesions. Therefore, targeting these viruses offers a novel therapeutic approach for virus-related cancers. In this study, codon optimization and site-direct mutagenesis were performed on HPV18 E6 and E7 genes, which were then cloned into a lentivirus vector to establish an HPV18 E6/E7-overexpressing cell line (EMT6-HPV18). EMT6-HPV18 cells stably expressed HPV18 oncogenes E6 and E7 in vitro and in vivo, and induced tumor formation in mice. To further investigate the potential of this model for evaluating HPV18-related anti-tumor drugs, we designed a self-replicating RNA (saRNA) expressing HPV18 E6 and E7, linked to FLT3L and CCL11 with the 3' and 5' terminal, respectively. Immunogenicity of the saRNA was validated after three rounds of immunizations by ELISpot and ICS flow cytometry, showing a marked increase in E6/E7-specific IFN-γ+ T cell response. Subsequently, the therapeutic effect was evaluated in the EMT6-HPV18 subcutaneous tumor model, where saRNA treatment remarkably inhibited tumor progression, improved early-stage survival rates, and induced long-term anti-tumor immunity. Immune profiling revealed significant infiltration of immune cells into the tumors post-saRNA treatment, namely CD4+ T cells, CD8+ T cells and DCs with significant increase in E6/E7 specific IFN+ T cell and memory T cell subsets. In conclusion, we have successfully established an HPV18 E6/E7-expressing tumor model, demonstrating that the saRNA therapeutic vaccine effectively inhibits tumor progression in HPV18-related malignancies. Citation Format: Zhongbao Song, GuangXu Ding, Anran Xia, Lihuan Bai, Wanqing Ma, Qiuhong Li, Xu Chen, Zhixiang Zhang, Qingyang Gu. HPV-related cancer model development and its application in the efficacy evaluation of a saRNA cancer vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 936