Blocking WNT7A Enhances MHC-I Antigen Presentation and Enhances the Effectiveness of Immune Checkpoint Blockade Therapy.

Abstract

The limited infiltration of CD8+ T cells in tumors hampers the effectiveness of T cell-based immunotherapy, yet the mechanisms that limit tumor infiltration by CD8+ T cells remain unclear. Through bulk RNA sequencing of human tumors, we identified a strong correlation between WNT7A expression and reduced CD8+ T-cell infiltration. Further investigation demonstrated that inhibiting WNT7A substantially enhanced MHC-I expression on tumor cells. Mechanistically, WNT7A inhibition inactivated Wnt/β-catenin signaling pathway and thus resulted in reduced physical interaction between β-catenin and p65 in the cytoplasm, which increased the nuclear translocation of p65 and activated the NF-κB pathway, ultimately promoting the transcription of genes encoding MHC-I molecules. We found that our lead compound, 1365-0109, disrupted the protein-protein interaction between WNT7A and its receptor FZD5, resulting in the upregulation of MHC-I expression. In murine tumor models, both genetic and pharmaceutical suppression of WNT7A led to increased MHC-I levels on tumor cells, and consequently enhanced the infiltration and functionality of CD8+ T cells, which bolstered antitumor immunity and improved the effectiveness of immune checkpoint blockade therapy. These findings have elucidated the intrinsic mechanisms of WNT7A-induced immune suppression, suggesting that therapeutic interventions targeting WNT7A hold promise for enhancing the efficacy of immunotherapy.