Isolation and characterization of biliary epithelial and stromal cells from resected human cholangiocarcinoma: a novel in vitro model to study tumor-stroma interactions

Cholangiocarcinoma (CCA) is a devastating malignancy arising from the bile ducts. Cancer-associated fibroblasts (CAFs) are key players in CCA invasiveness and in the generation of a desmoplastic reaction. The aim of the present study was to develop a novel model by which to study tumor-stroma interactions using primary cultures of human biliary epithelial cells (hBECs) and stromal cells (SCs) in CCA. hBECs and SCs, isolated from surgical resections (n=10), were semi-purified by centrifugation on a Percoll gradient; hBECs were further immunopurified. hBECs and SCs were characterized using epithelial [cytokeratin 7 (CK7) and CK19] and mesenchymal [vimentin (VMN), α-smooth muscle actin (α-SMA), CD68] cell markers. The purity of cultured cells was assessed by fluorescent immunocytochemistry. hBECs were HEA125/CK7/CK19-positive and VMN/α-SMA-negative. SCs were VMN/α-SMA-positive and CK7/CK19-negative. CCA 2-D culture models have been described but they use long-standing CCA cell lines of various biliary tumor cell origins with stromal cells derived from non-cholangiocarcinoma tissues. Recently, a novel 3-D organotypic co-culture model of rat cholangiocarcinoma was described. In the present study, we obtained pure and stable primary cultures of hBECs and SCs from CCA surgical specimens. These cell cultures may provide a useful tool by which to study CCA tumor-stroma interactions.