Supporting data for PhD thesis "Development of Cancer Immunotherapeutic Strategies Based on Multi-Dimensional Understanding of Cancer Immunology"

The field of cancer immunotherapy has experienced significant advancements, particularly with the development of innovative therapies. These include cancer neoantigen vaccines that stimulate systemic tumor-specific immune responses, immune checkpoint inhibitors (ICIs) that revitalize tumor-specific immune cells, chimeric antigen receptor T-cell (CAR-T) therapy that introduces large numbers of tumor-specific T cells for effective eradication, and antibody-based treatments that enable targeted attacks. Despite these significant developments, the effectiveness of these therapies is often limited by tumor-induced immunosuppression and resistance within the tumor microenvironment (TME). Furthermore, cancer is increasingly recognized as a systemic disease characterized by immune status alterations throughout the body, underscoring the imperative for therapies that address both systemic and intratumoral immune activation.

This study explores novel cancer therapeutic strategies through a comprehensive understanding of cancer immunology. Initially, we developed and optimized a neoantigen vaccine-based therapeutic strategy aimed at systemically activating tumor-specific immune responses and improving the TME. This was achieved by combining α-Galactosylceramide (α-GalCer) to activate invariant natural killer T (iNKT) cells, which resulted in improved treatment outcomes. Although this approach successfully reversed inhibitory immune cells, it was insufficient to overcome tumor heterogeneity. To address this, we introduced allogeneic major histocompatibility complex (MHC) molecules within tumors to label them, thereby enhancing their recognizability and addressing heterogeneity. However, this strategy did not adequately activate the corresponding systemic immune response, impacting overall efficacy.

To overcome these limitations, we further refined our strategy to concurrently activate systemic and intratumoral immunity. Our research demonstrated that incorporating a systemic immunity activation step against the same allogeneic MHC significantly improved therapeutic outcomes. To enhance efficacy further, we replaced the allogeneic MHC with pathogen-derived antigens, which increased the antigenicity and immunogenicity of the tumor. Our data showed that using an mRNA vaccine platform to establish a systemic anti-pathogen antigen immune response, followed by the introduction of the same antigen within the tumor, effectively marked tumor cells with pathogen antigen proteins. This rapidly activated a systemic pathogen antigen-specific immune response, leading to the elimination of marked tumor cells. The subsequent eradication of these cells triggered antigen spreading, inducing a broader tumor-specific immune response against heterogeneous tumor cells.

This strategy effectively combines systemic and intratumoral immune activation while improving the TME and overcoming tumor heterogeneity. Consequently, this pathogen antigen mRNA vaccine-based cancer immunotherapy shows promise as a potent, broad-spectrum, off-the-shelf treatment. It offers the potential to achieve multiple cancer treatment goals with a single drug, paving the way for future combinational therapies. Given that a large portion of the global population has developed immune memory against various pathogens through infection or vaccination—particularly SARS-CoV-2—we predict that mRNA lipid nanoparticle-based vaccines targeting pathogens such as SARS-CoV-2, Hepatitis B Virus (HBV), Common Human Coronaviruses (HCoVs), and the influenza virus could provide a comprehensive immunotherapy strategy for various cancers. The extensive selection of pathogen antigens broadens therapeutic opportunities and reduces the risk of drug resistance. We believe this therapeutic approach could rapidly transition into clinical use, offering a promising alternative for cancer patients and setting the stage for future combinational treatments.