Abstract 4448: Chemokine (C-X-C motif) ligand 17 promotes cutaneous squamous cell carcinoma via modulating tumor-immune evasion

Abstract Cutaneous squamous cell carcinoma (cSCC) is a keratinocyte-derived invasive and metastatic tumor of the skin. It is the second-most commonly diagnosed form of skin cancer, striking 200,000 Americans annually. Further, organ transplant patients are at significantly increased risk of cSCC compared to the general population. Excision of cSCC of the head and neck area results in significant facial disfigurement. An increased understanding of the mechanisms involved in the pathogenesis of cSCC could identify means to prevent, inhibit, and reverse this process. Chemokine (C-X-C motif) ligand 17 (CXCL17) is the latest chemokine family member, and an increased CXCL17 protein expression was observed in both mouse and human cSCC cell lines. Further, deletion of CXCL17 was associated with significant inhibition of tumor cell-intrinsic properties such as proliferation, migration, and motility. CXCL17 is identified as a potent chemoattractant for macrophages, dendritic cells and myeloid-derived suppressive cells. Accordingly, utilizing a syngeneic, tumor-cell xenograft cSCC mouse model, we evaluated the effect of CXCL17 deletion on cSCC tumor-immune evasion and elucidated the underlying mechanism. Deletion of CXCL17 was associated with a significant reduction in tumor volume compared to the wild-type counterparts. Further, CXCL17 deleted cSCC tumor cell xenografts exhibited a significant increase in CD8+, cytotoxic T cells in the tumor microenvironment, suggesting an important role of CXCL17 in mediating tumor-immune evasion. Interestingly, treatment with CXCL17 induced macrophage M2 polarization and promoted macrophage efferocytosis via modulating efferocytotic machinery proteins such as MERTK, TIM4, GAS6 and AXL. Our studies have established substantial evidence for the role of CXCL17 in modulating tumor-cell extrinsic properties to affect the progression of cSCC. Citation Format: Alok R. Khandelwal, Rema Anisha Kandula, Emily Daniel, Md Maksudul Alam, Henry Craighead, Tara Moore-Medlin, Cherie-Ann O. Nathan. Chemokine (C-X-C motif) ligand 17 promotes cutaneous squamous cell carcinoma via modulating tumor-immune evasion. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4448.