Abstract
Interleukin 37 (IL-37), a member of the IL-1 family, is considered a suppressor of innate and adaptive immunity and, hence is a regulator of tumor immunity. However, the specific molecular mechanism and role of IL-37 in skin cancer remain unclear. Here, we report that IL-37b-transgenic mice (IL-37tg) treated with the carcinogenic 7,12-dimethylbenzoanthracene (DMBA)/12-o-tetradecylphorbol-13-acetate (TPA) exhibited enhanced skin cancer and increased tumor burden in the skin by inhibiting the function of CD103+ dendritic cells (DCs). Notably, IL-37 induced rapid phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and via single immunoglobulin IL-1-related receptor (SIGIRR), inhibited the long-term Akt activation. Specifically, by affecting the SIGIRR-AMPK-Akt signaling axis, which is related to the regulation of glycolysis in CD103+DCs, IL-37 inhibited their anti-tumor function. Our results show that a marked correlation between the CD103+DC signature (IRF8, FMS-like tyrosine kinase 3 ligand, CLEC9A, CLNK, XCR1, BATF3, and ZBTB46) and chemokines C-X-C motif chemokine ligand 9, CXCL10, and CD8A in a mouse model with DMBA/TPA-induced skin cancer. In a word, our results highlight that IL-37 as an inhibitor of tumor immune surveillance through modulating CD103+DCs and establishing an important link between metabolism and immunity as a therapeutic target for skin cancer.