Abstract 1575: Intratumoral injection of interleukin-17 inhibits distant metastasis of radiation-induced recurrent tumor

Interleukin-17 (IL-17) is a pro-inflammatory cytokine that leads to the production of GM-CSF, G-CSF, IL-1, IL-6, TNF-α. It can be secreted by various cells, including T cells, NKT cells, fibroblasts, and even tumor cells. In addition, reports have shown that IL-17 could also promote tumor growth by recruiting and expanding granulocytic myeloid suppressor cells (G-MDSCs). In our preliminary study, we found that Tramp-C1, a murine prostate cancer cell line, had remarkable IL-17 level when it grew in pre-irradiated (PreIR) stroma. In contrast, B16F0, a murine melanoma cell line, had much less IL-17 and stronger tumor bed effect, in terms of tumor growth delay, but lung metastasis were formed gradually as B16F0 developed. When the recombinant IL-17 was directly injected into the B16F0 tumors growing in PreIR stroma, we found that the probability of lung metastasis was decreased despite a slight increase of tumor growth at primary site. This indicates that IL-17 may have different effects on irradiated tumor bed and distant metastatic site. The influence of IL-17 on tumor microenvironments of distant metastatic sites and irradiated tumor bed is currently under investigation. In conclusion, we propose a new therapeutic approach of reducing distant metastasis following radiation therapy.. This work was kindly supported by MOST-104-2314-B-182 -024 grant to Fang-Hsin Chen. Citation Format: Yi-Nan Li, Fang-Hsin Chen, Ji-Hong Hong, Chi-Shiun Chiang. Intratumoral injection of interleukin-17 inhibits distant metastasis of radiation-induced recurrent tumor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1575.