Proteomic analysis of IL33-proximal proteins in squamous cell carcinoma cells

Focal adhesion kinase (FAK) is required for the expression of pro-inflammatory genes that inhibit anti-tumour immunity. Here, we show a novel and crucial role for the dual-function cytokine IL33 in FAK-dependent immune evasion. Specifically, nuclear FAK is required for the expression of IL33, the chemokine Ccl5 and the soluble form of the IL33 receptor, sST2, which are required for evasion of CD8+ T-cell-mediated anti-tumour immunity. Mechanistically, nuclear IL33 associates with FAK and a network of chromatin modifiers and transcriptional regulators, including Taf9, WDR82 and BRD4, while sST2 likely negates effects of IL33 secreted into the tumour microenvironment by infiltrating host immune cells. Finally, protein interaction network analysis implies that nuclear FAK–IL33 complexes impact on transcription factors that regulate NFkB and chemokines like Ccl5 downstream. Our data therefore provide new mechanistic insight into how FAK controls the tumour immune environment via a FAK–IL33/sST2 pathway and demonstrate a novel role for nuclear IL33 downstream of FAK as a component of transcription regulatory complexes that critically modulate anti-tumour immunity.