High throughput screen in a co-culture model to uncover therapeutic strategies to potentiate the cancer-inhibiting properties of the tumor-stroma in pancreatic cancer

P ancreatic stellate c ells (PSCs) differentiate into multiple subtypes of c ancer a ssociated fibroblasts (CAFs) that modulate disease progression in p ancreatic d uctal a deno c arcinoma (PDAC). CAF subtypes demonstrate functional heterogeneity in tumor development, with conflicting consequences for disease progression. Here, we show that my ofibroblastic CAFs (myCAFs), but not inflammatory CAFs (iCAFs), can act to restrain tumor cell growth in an in vitro PDAC model of tumor organoids co-cultured with PSCs. Inhibiting myCAF formation by TGF-β pathway inhibition improved tumor organoid growth, indicating that manipulating the balance of CAF subtypes may be exploited as a therapeutic approach. We therefore conducted a high throughput screen of approximately 36,000 compounds on the co-culture model to find novel compounds to inhibit PDAC tumor cell growth via CAF manipulation. We identify a new role for GNF-5, a known Ab elson tyrosine kinase (Abl) inhibitor, in the context of PDAC as a compound that inhibits tumor cell growth in co-culture; an effect that was accompanied by an induction of the myCAF phenotype around tumor organoids. This highlights the therapeutic potential of novel therapies targeting specific CAF subtypes in PDAC.