Abstract P019: Intra-tumoral nerves regulate the local immune response at the tumor bed

Abstract

Abstract Patients with highly innervated tumors have a worse prognosis than those with less innervated disease. However, the process by which intra-tumoral nerves contribute to poor outcomes remains unclear. Previously, we identified that head and neck squamous cell carcinomas (HNSCCs) are infiltrated by sensory (TRPV1+) nerves. To map the source of these tumor infiltrating nerves, we intra-tumorally injected the fluorescently tagged nerve tracer lectin, wheat germ agglutinin (WGA), in our hind limb placed HNSCC tumors. Similar to other nerve tracers, WGA is taken up at nerve terminals and retrogradely transported to the neural somas. WGA labeled the somas of dorsal root ganglia (DRG), identifying them as the source of intra-tumoral nerves. Traced nerves were further characterized by immunostaining and identified as TRPV1+ (sensory), consistent with our initial findings. To test the contributions of tumor innervation to tumor growth and survival, wildtype and TRPV1-DTA (genetically deleted of TRPV1+ neurons) mice were implanted with a mouse model of human papillomavirus-induced (HPV+) HNSCC, mEERL cells. The absence of TRPV1 nerves results in slower tumor growth and improves survival. To mechanistically define how depletion of intra-tumoral nerves reduce tumor growth, we first collected tumors 25 days after injection in the hind limb and stained with a 12-color antibody panel. Stained tumors were then analyzed with flow cytometry to identify differences in the infiltrative immune cell populations between tumors grown in C57Bl/6 control mice and our TRPV1-DTA mouse model. Flow cytometry analysis indicated a decrease in the infiltrative myeloid derived suppressor cell (MDSC) population following ablation of TRPV1+ nerves. To understand how loss of TRPV1+ nerves mediate changes in the infiltrative immune cell population we conducted cytokine array analysis of condition media from cancer cells alone and in co-culture with DRG. Results indicate a shift in secreted cytokines following co-culture with DRG. These data indicate that intra-tumoral sensory nerves are recruited from loco-regional DRG to tumors injected in the hind limb. Our data also suggest that ablation of TRPV1+ nerves alter the intra-tumoral MDSC population and, in this way, potentially contributes to tumor growth. Finally, co-culture of mEERL cells with DRG in vitro results in changes in secreted cytokines, potentially explaining the change in the infiltrative immune cell populations. Together, these data indicate a potential role for sensory nerves to regulate the local immune response in developing tumors. Citation Format: Anthony C. Restaino, Christopher T. Lucido, Jeffrey Barr, Paola D. Vermeer. Intra-tumoral nerves regulate the local immune response at the tumor bed [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P019.