Boosting innate T cell responses in colon cancer

Supervisors

Seth Coffelt, School of Cancer Sciences, University of Glasgow 

Joanne Edwards, School of Cancer Sciences, University of Glasgow

Industry Partner: AstraZeneca UK

 

Summary

The importance of T cells is well established in colorectal cancer, as their abundance in tumours predicts a good outcome in cancer patients. However, for the largest group of colorectal cancers – the microsatellite stable (MSS) group, which represents 80-85% of cases – T cells are largely absent from tumours. Patients with MSS tumours respond poorly to T cell checkpoint inhibitors, such as anti-PD-1. Thus, a greater understanding of how T cells are excluded from MSS tumours is required. Across the genomic landscape of MSS tumours, mutations in WNT/beta-catenin-related genes are the strongest correlative of low T cell infiltration. Thus, the overall goal of this proposal is to mechanistically dissect the interaction between WNT/beta-catenin signalling, immunosurveillance and immune escape in colon cancer.

This proposal will specifically focus on intraepithelial lymphocytes (IELs), a group of gut-resident, unconventional T cells consisting of both alpha/beta T cells and gamma/delta T cells, rather than conventional, dendritic cell-educated CD8+ T cells. The Coffelt lab has discovered that IELs recognize and kill pre-cancerous gut epithelial cells. We have found that WNT signalling negatively regulates T cell interacting molecules, but downregulation of these proteins is reversible if WNT signalling is inhibited.