Disruption of fibroblast MYD88 signaling promotes antitumor immunity in pancreatic ductal adenocarcinoma

Abstract

Pancreatic ductal adenocarcinoma (PDAC) continues to carry a dismal prognosis. The disease is characterized by a uniquely dense fibrotic matrix generated by cancer-associated fibroblasts (CAFs). We have previously demonstrated that fibroblast-driven chronic inflammation suppresses T cell function through a myeloid differentiation primary response protein 88 (MYD88)-dependent mechanism. While extensively studied in myeloid cells, the role of MYD88 signaling in CAFs and its effects on PDAC remain poorly understood. In this study, we identify a MYD88-driven inflammatory CAF population in PDAC using a combination of bulk, single-cell, and spatial transcriptomic studies. Using an innovative collagen gel implantation model, we demonstrate that loss of MYD88 in CAFs enhances T cell infiltration and suppresses tumor growth. Combining MYD88 inhibition with immune checkpoint blockade significantly reduces tumor size and enhances antitumor immune responses, underscoring its potential as a therapeutic target in PDAC.

Keywords: CA-4948; CP: Cancer; CP: Immunology; MYD88; PDAC; cancer-associated fibroblast; immune checkpoint blockade; inflammatory CAF; pancreatic ductal adenocarcinoma.