An HNSCC syngeneic mouse model for tumor immunology research and preclinical evaluation

The lack of reliable animal models to assess the safety and efficacy of drugs and to explore the underlying molecular mechanisms is one of the most severe impediments in head and neck squamous cell carcinoma (HNSCC) tumor immunology research. The majority of xenograft tumor models established using immunodeficient mice neglect the effects of T cells. To date, to the best of our knowledge, there is no syngeneic tumor model available that reflects the immune microenvironmental features of HNSCC tumors. To solve this issue, the present study used 4-nitroquinoline-1-oxide (4-NQO) to induce squamous cell carcinoma in C57BL/6 mice. Three HNSCC cell lines were then established, and one of these, termed JC1, was selected for further analysis due to its enhanced proliferative ability and tumorigenicity in immunodeficient nude mice. However, none of the 3 cell lines could form tumors in immunocompetent mice. Due to the different tumorigenicities in nude and C57BL/6 mice, the immune system may play an important role in inoculated JC1 tumor progression. Chemical induction was used to establish the tumorigenicity-enhanced cell line, JC1-2, which can form syngeneic tumors in immunocompetent C57BL/6 mice. Next-generation sequencing (NGS) was used to perform the immunogenomic and transcriptomic characterization of the JC1-2 cells. Splenocytes were isolated from C57BL/6 mice and co-cultured with JC1-2 cells to verify the responsiveness of the interferon (IFN)-γ pathway in the JC1-2 cell line. Unlike the majority of syngeneic mouse tumors, the JC1-2-formed tumors resembled 'inflamed tumors' due to the abundancy of immune cells in the tumor microenvironment. Moreover, more intense immune responses were observed in the orthotopic mouse model than in the heterotopic model. Thus, this model could be used to delineate the interactions between HNSCC and lymphocytes, and to validate novel immunotherapy targets.