Heterocellular OSM-OSMR signalling drives pancreatic cancer growth and metastasis through functional fibroblast reprogramming

Pancreatic ductal adenocarcinoma (PDA) is a lethal malignancy characterised by a pathological fibroinflammatory microenvironment. Dichotomous tumour-promoting and -restrictive roles have been ascribed to the tumour microenvironment, however the effects of individual stromal subsets remains incompletely characterised. Here, we describe how heterocellular OSM-OSMR signalling instructs fibroblast reprogramming, tumour growth and metastasis. Macrophage-secreted OSM stimulates inflammatory gene expression in cancer-associated fibroblasts (CAFs), which in turn induce a pro-tumorigenic environment and engage tumour cell survival and migratory signalling pathways. Tumour cells implanted in Osm-deficient (Osm-/-) mice display an epithelial-dominated morphology, reduced tumour growth and did not metastasise. Moreover, the tumour microenvironment of Osm-/- animals exhibit increased abundance of aSMApos myofibroblasts and a shift in myeloid and T cell phenotypes, consistent with a more immunogenic environment. Taken together, these data demonstrate how OSM-OSMR signalling coordinates heterocellular interactions to drive a pro-tumorigenic environment in PDA. Overall design: RNAsequencing of pancreatic stellate cells from mono-culture and isolated from co-culture with tumour cells or tumour cells and macrophages. 4 biological replicates for each culture condition