Abstract 5167: Cell autonomous and non-autonomous actions of CCL22 in oral carcinogenesis

Abstract

Abstract Oral cancer, a subtype of head and neck cancer, has been the 4th leading cause of male cancer death in Taiwan for the past decade. Smoking, alcohol consumption, and betel quid chewing are major risk factors for oral cancer in Taiwan. The crosstalk between immunity and cancer cells can both inhibit and enhance tumor growth and is now classified as a cancer hallmark. The accumulation of regulatory T cells (Tregs) in several tumor types potentially plays a critical role in tumor evasion of immune surveillance. Oral cancer is also characterized by an increase in the number of infiltrating Tregs; however, the significance of the increase on the patient prognosis remains controversial. We found that the expression of CCL22, a chemokine for Treg recruitment, was not only positively with poor prognosis in oral cancer patients but also significantly correlated with that of FOXP3, a master regulator for Treg development and functions, in the same patients. The correlation is also validated in TCGA database analysis of head and neck cancer patients. The depletion of CCL22 expression reduced oral cancer cell proliferation, migration and invasion, suggesting an oncogenic role of CCL22 in oral cancer. Since CCR4 is the receptor for CCL22, we studied the in vitro and in vivo impact of deregulated CCL22-CCR4 signaling axis in oral carcinogenesis. We first confirmed the surface expression of CCR4 in oral cancer cells by flow cytometry. Ectopic CCL22 overexpression increased oral cancer cell migration and invasion without the effect on proliferation. Through injection of CCL22-altered oral cancer cells in both syngeneic and athymic backgrounds, the cell autonomous and non-autonomous actions of CCL22 and the mechanism responsible for the CCL22 deregulation in oral cancer will be discussed. This study will not only further the role of CCL22-CCR4 signaling axis in modulating the crosstalk between oral cancer and its microenvironment but also provide a novel therapeutic strategy for treating oral cancer. Citation Format: Li-Wha Wu. Cell autonomous and non-autonomous actions of CCL22 in oral carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5167.