Abstract
A mesenchymal tumor phenotype associates with immunotherapy resistance, although the mechanism is unclear. Here, we identified FBXO7 as a maintenance regulator of mesenchymal and immune evasion phenotypes of cancer cells. FBXO7 bound and stabilized SIX1 co-transcriptional regulator EYA2, stimulating mesenchymal gene expression and suppressing IFNα/β, chemokines CXCL9/10, and antigen presentation machinery, driven by AXL extracellular ligand GAS6. Ubiquitin ligase SCFFBXW7 antagonized this pathway by promoting EYA2 degradation. Targeting EYA2 Tyr phosphatase activity decreased mesenchymal phenotypes and enhanced cancer cell immunogenicity, resulting in attenuated tumor growth and metastasis, increased infiltration of cytotoxic T and NK cells, and enhanced anti-PD-1 therapy response in mouse tumor models. FBXO7 expression correlated with mesenchymal and immune-suppressive signatures in patients with cancer. An FBXO7-immune gene signature predicted immunotherapy responses. Collectively, the FBXO7/EYA2-SCFFBXW7 axis maintains mesenchymal and immune evasion phenotypes of cancer cells, providing rationale to evaluate FBXO7/EYA2 inhibitors in combination with immune-based therapies to enhance onco-immunotherapy responses.