A micro-vascularized pancreatic ductal adenocarcinoma-on-chip model recapitulates immune exclusion and altered T cell polarization

Pancreatic ductal adenocarcinoma (PDAC) demonstrates strong immune evasion by reshaping the tumor microenvironment (TME) into an anti-inflammatory, immunosuppressive niche. This process involves creating chemokine gradients and physical barriers that hinder the recruitment and infiltration of immune effector cells.To study these interactions under physiologically relevant conditions, we developed a PDAC-on-chip model using a microfluidic three-channel biochip. The system was based on PDAC co-spheroids composed of primary cancer-associated fibroblasts (CAFs) and Panc1 tumor cells embedded in an extracellular matrix within a dedicated chip channel. Over 10 days, fibroblasts generated a fibrotic barrier exceeding 100 µm around the tumor core. Concurrently, endothelial cells integrated into the matrix formed a perfusable microvascular network directly interfacing with the TME. Various immune cell populations were introduced into the vascular channel, and their transmigration across a porous membrane through the microvasculature into the complex TME was tracked over time using live-cell imaging and flow cytometry.Our findings show that PDAC-on-chip models effectively restrict T cell infiltration, reinforcing the concept of active immune exclusion by the tumor. Moreover, activated CD8 T cells recovered from the chip exhibited an altered activation phenotype characterized by HLA-DR downregulation and 4.1BB upregulation. This microvascularized PDAC-on-chip platform faithfully reproduces key features of PDAC immune evasion observed in vivo and provides a promising tool for evaluating immunotherapeutic strategies in a controlled microphysiological setting.