Novel organotypic culture model of cholangiocarcinoma progression

Abstract

Recent studies have suggested that increased α-smooth muscle-actin positive myofibroblastic cells (α-SMA positive CAF) in the desmoplastic stroma may relate to a more aggressive cancer and worse survival outcomes for intrahepatic cholangiocarcinoma (ICC) patients. To facilitate investigating cellular and molecular interactions between α-SMA positive CAF and cholangiocarcinoma cells related to ICC progression, we developed a novel 3-D organotypic culture model of cholangiocarcinoma that more accurately mimics the stromal microenvironment, gene expression profile and select pathophysiological characteristics of desmoplastic ICC in vivo. This unique model was established by co-culturing within a type I collagen gel matrix, a strain of cholangiocarcinoma cells (derived from an ICC formed in syngeneic rat liver following bile duct inoculation of spontaneously-transformed rat cholangiocytes) with varying numbers of clonal α-SMA positive CAF established from the same tumor type. Cholangiocarcinoma cells and α-SMA positive CAF in monoculture each exhibited cell-specific biomarker gene expression profiles characteristic of stromal myofibroblastic cell versus malignant cholangiocyte cell types. In comparison, the gene expression profile and histopathological characteristics exhibited by the organotypic co-culture closely resembled those of whole tissue samples of the parent orthotopic ICC. We further showed α-SMA positive CAF to significantly enhance cholangiocarcinoma cell "ductal-like" growth and cancer cell migration/invasiveness in vitro, as well as to promote upregulated expression of select genes known to be associated with ICC invasion. This novel organotypic model provides an important new resource for studying the effects of microenvironment on cholangiocarcinoma progression in vitro and may have potential as a preclinical model for identifying molecularly targeted therapies.