Abstract 5009: DKK1 is a potential target for enhancing the efficiency of radioimmunotherapy in head and neck squamous carcinoma

Abstract

Abstract Immune checkpoint inhibitors (ICIs) have been approved to treat various types of tumors, including head and neck squamous carcinoma (HNSC). However, most HNSC patients do not respond to ICIs. Radioimmunotherapy has been proposed to enhance the immune response rate in HNSC. Herein, we aimed to explore the effect of DKK1 on radiotherapy and immunotherapy in HNSC. We collected the gene expression profile and clinical information of HNSC patients from TCGA, GEO, and ICGC. The immune cell infiltration, level of related pathways and biological processes, signature scores of gene sets of interest were assessed using CIBERSORT, GSEA or GSVA respectively. One of the genes, Dickkopf-1 (DKK1), a secreted protein which plays important roles in the Wnt signaling pathways, was identified because of its significantly higher expression in HNSC. Then, we confirmed the DKK1 expression at protein level by immunohistochemistry of HNSC tissue microarray. CCK8, apoptosis detection and survival curves were performed to investigate the response of DKK1-knockdown HSC-3 cell line to radiation. We found the mRNA and protein expression level of DKK1 was significantly higher in HNSC tissue. The DKK1high group had a shorter survival time in both disease-free survival and overall survival than the DKK1low group. The DKK1high group showed a more immunosuppressive microenvironment with lower infiltration of T cells and higher infiltration of MDSCs. Furthermore, the DKK1high group was enriched in radioresistance related to wound healing, angiogenesis, and autophagy. Patients in the DKK1high group who received radiotherapy had much poorer disease-free survival and overall survival than those in the DKK1low group. HSC-3 cell line was more sensitive to radiation after knockdown of DKK1 by siRNA. Finally, we established a risk score system based on the 9 genes from 41 DKK1-associated immunomodulators and created a nomogram model to predict the prognosis of the patients. Our data show that DKK1 can affect both radiotherapy and immunotherapy in HNSC, suggesting that DKK1 can be a potential target for radioimmunology in HNSC. Citation Format: Xinyu YE, JIAN Zhang, Yi Lu, Yingxuan Gong, Xinyu Jiang, Yueming Li, Yinghao Wang, Xiuzhi Li, Jingwen Liu, Rencui Quan. DKK1 is a potential target for enhancing the efficiency of radioimmunotherapy in head and neck squamous carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5009.