Human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) is a fast-growing health problem in the United States. By analyzing the transcriptomes of HPV-positive (HPV+) and HPV-negative (HPV-) HNSCC patient tissues, we previously revealed that expression of CXCL14, constitutively expressed in basal epithelial cells, is downregulated in HPV-positive HNSCC. In contrast, the expression of proinflammatory chemokines, particularly CXCL1, CXCL2, and CXCL8, are significantly upregulated in both HPV+ and HPV- HNSCCs. We further showed that restored expression of CXCL14 in HPV+ HNSCC cells leads to tumor-free survival in vivo by increasing MHC-I antigen presentation on the cancer cell surface and CD8+ T cell activation. Interestingly, high CXCL1, CXCL2, and CXCL8 expression levels significantly correlate to poor HNSCC patient survival, showing an exact opposite pattern of the clinical outcomes associated with the CXCL14 expression levels. To determine the roles of these chemokines in HPV+ HNSCC development, CXCL1 and CXCL2 genes (no murine CXCL8 ortholog) were deleted using a CRISPR-Cas9 knockout system in HPV+ murine HNSCC cells. Using these stably engineered HNSCC cells, we investigated tumor growth, immune cell infiltration, and metastasis in immunocompetent syngeneic mice. Interestingly, the deletion of CXCL1 and CXCL2 significantly delays in vivo tumor growth, decreases myeloid-derived suppressor cell (MDSC) infiltration in the tumor, and decreases lung metastasis. However, the numbers of natural killer (NK), CD4+, and CD8+ T cells in the tumor microenvironment were not affected by CXCL1 and CXCL2 knockout. Next, mice injected with the murine HNSCC cells were treated twice daily with AZD5068, a selective inhibitor of CXCR2, which is a common receptor of CXCL1, CXCL2, and CXCL8 expressed on myeloid cells. Our result showed that the treatment of CXCR2 suppresses in vivo tumor growth in a similar pattern with CXCL1 and CXCL2 knockout. These results suggest that the dysregulation of chemokine expression in HPV-infected cells plays an important role in regulating tumor growth, antitumor immune responses, and metastasis of HPV+ HNSCC. Our findings may provide promising strategies to develop novel immunotherapies for HPV+ HNSCC patients which can likely be extended to other non-viral cancers with immunosuppressive phenotypes.
Citation Format: Daniel Vermeer, Joseph Westrich, Paul Colbert, Craig Welbon, John H. Lee, David Raben, William C. Spanos, Dohun Pyeon. Chemokine dysregulation creates the immunosuppressive tumor microenvironment and promotes human papillomavirus-associated head and neck cancer [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 P042.