FGFR2 fusion protein-driven mouse models of intrahepatic cholangiocarcinoma unveil a necessary role for Erk signaling

Abstract

All Authors, except M.J.B., have no personal, professional or financial conflicts to disclose. M.J.B. AbstractBackground and aims. About 15% of intrahepatic cholangiocarcinoma (iCCA) express fibroblast growth factor receptor 2 (FGFR2) fusion proteins (FFs), most often in concert with mutationally inactivated TP53, CDKN2A or BAP1. FFs span residues 1-768 of FGFR2 fused to sequences encoded by any of a long list (>60) of partner genes, a configuration sufficient to ignite oncogenic FF activation. In line, FGFR-specific tyrosine kinase inhibitors (F-TKI) were shown to provide clinical benefit in FF+ iCCA, although responses were partial and/or limited by resistance mechanisms, including the FF V565F gatekeeper mutation. Herein we present an FF-driven murine iCCA model and exploit its potential for pre-clinical studies on FF therapeutic targeting.Methods. Four iCCA FFs carrying different fusion sequences were expressed in Tp53 -/mouse liver organoids. Tumorigenic properties of genetically modified liver organoids were assessed by intrahepatic/subcutaneous transplantation in immuno-deficient mice. Cellular models derived from neoplastic lesions were exploited for pre-clinical studies. Results. Tumors diagnosed as CCA were obtained upon transplantation of FF-expressing liver organoids. The penetrance of this tumorigenic phenotype was influenced by FF identity. Tumor organoids and 2D cell lines derived from CCA lesions were addicted to FF signaling via Ras-Erk, regardless of FF identity or presence of V565F mutation. Double blockade of FF-Ras-Erk pathway by concomitant pharmacological inhibition of FFs and Mek1/2 provided greater therapeutic efficacy than single agent F-TKI in vitro and in vivo. Conclusions. FF-driven iCCA pathogenesis was successfully modelled in murine Tp53 -/background. This model revealed biological heterogeneity among structurally different FFs. Double blockade of FF-Erk signaling deserves consideration for improving precision-based approaches against human FF+ iCCA.

Oncogenic KRAS–expressing organoids with biliary epithelial stem cell properties give rise to biliary tract cancer in mice

“…Mouse models engineered with the use of the cytokeratin 19 (CK19) gene promoter develop not only cholangiocarcinoma but also neoplastic lesions in a variety of tissues including pancreatic ducts, gastric and colonic mucosa, and lung 9,10 . Recently, several organoid‐based mouse models of human IHCC, EHCC, and GC have been established and have shed light on the pathogenesis of human BTC 9,11‐14 . Organoid culture is a type of 3D culture that supports the formation of budding, cystlike structures from stem cells 15 .…”

“…9,10 Recently, several organoid-based mouse models of human IHCC, EHCC, and GC have been established and have shed light on the pathogenesis of human BTC. 9,[11][12][13][14] Organoid culture is a type of 3D culture that supports the formation of budding, cystlike structures from stem cells. 15 Organoid models of the normal small intestine, colon, liver, and pancreas of mice have been established.…”