Highly Immunogenic Cancer Cells Require Activation of the WNT Pathway for Immunological Escape

ABSTRACT: PD-1 blockade therapy exerts antitumor effects by restoring the infiltration of tumor antigen-specific CD8+ T cells. While neoantigens arising from gene alterations in cancer cells comprise critical tumor antigens in antitumor immunity, a subset of non-small-cell lung cancers (NSCLCs) harboring substantial tumor mutation burden (TMB) lack CD8+ T cells in the tumor microenvironment (TME), resulting in resistance to PD-1 blockade therapy. This resistance is an urgent issue, so the mechanism(s) mediating impaired antitumor immunity in highly mutated NSCLCs need to be explored. Here, we show that activation of the WNT/b-catenin signaling pathway contributes to the development of a noninflamed TME in tumors with high TMB. NSCLCs that lack immune cell infiltration into the TME despite high TMB preferentially upregulate the WNT/b-catenin pathway. Immunological assays revealed that those patients harbored neoantigen-specific CD8+ T cells in the peripheral blood but not in the TME, suggesting impaired T cell infiltration into the TME due to the activation of WNT/b-catenin signaling. In our animal model, the accumulation of gene mutations in cancer cells increased CD8+ T cell infiltration into the TME, slowing tumor growth. However, further accumulation of gene mutations blunted antitumor immunity by excluding CD8+ T cells from tumors in a WNT/b-catenin signaling-dependent manner. Combined treatment with PD-1 blockade and WNT/b-catenin signaling inhibitors induced far stronger antitumor immunity than either treatment alone. We propose a mechanism-oriented combination therapy concept in the cancer immunotherapy field, i.e., the combination of immune checkpoint inhibitors with drugs that target specific molecules in cancer cell-intrinsic oncogenic signaling pathways involved in immune escape.

ORGANISM(S): Homo sapiens

PROVIDER: GSE181820 | GEO | 2021/09/17

REPOSITORIES: GEO