Pancreatic ductal adenocarcinoma (PDAC) is typically associated with an immunologically "cold" phenotype, mainly due to a highly immunosuppressive tumour microenvironment (TME) orchestrated by cancer-associated fibroblasts (CAFs). This environment is a major obstacle to immunotherapeutic strategies, including immune checkpoint inhibitors, as PDAC is often resistant to such treatments. Therefore, a novel therapeutic approach may involve targeting CAFs to transform PDAC from a 'cold' to a 'hot' tumour, opening up new treatment options.

Recent research suggests that monoclonal antibodies targeting CAFs have had limited clinical success. In response, we have developed a novel approach using chimeric antigen receptor natural killer (CAR NK) cells to specifically target CAFs. This development was facilitated by using the Beacon optofluidic system to generate amonoclonal antibody against endoglin, which is overexpressed in CAFs. Using this method, we identified and refined a selection of 25 viable antibody candidates.

These candidates were instrumental in the development of anti-CAF CAR NK cells. We conducted a thorough evaluation of the cytotoxicity of these cells against endoglin-positive target cell lines and CAFs. In particular, the CL-EN-024 clone demonstrated a targeted cytotoxic effect with significantly higher efficacy than our positive control.

Our findings suggest that the use of anti-CAF CAR NK cells can effectively target and eliminate CAFs, potentially transforming PDAC into a tumour type more amenable to immunological intervention. This could significantly improve the efficacy of current PDAC therapies and pave the way for more responsive and dynamic treatment options.