title: Epithelial-to-Mesenchymal Transition and Cancer Invasiveness: What Can We Learn from Cholangiocarcinoma?
abstract: In addition to its well-established role in embryo development, epithelial-to-mesenchymal transition (EMT) has been proposed as a general mechanism favoring tumor metastatization in several epithelial malignancies. Herein, we review the topic of EMT in cholangiocarcinoma (CCA), a primary liver cancer arising from the epithelial cells lining the bile ducts (cholangiocytes) and characterized by an abundant stromal reaction. CCA carries a dismal prognosis, owing to a pronounced invasiveness and scarce therapeutic opportunities. In CCA, several reports indicate that cancer cells acquire a number of EMT biomarkers and functions. These phenotypic changes are likely induced by both autocrine and paracrine signals released in the tumor microenvironment (cytokines, growth factors, morphogens) and intracellular stimuli (microRNAs, oncogenes, tumor suppressor genes) variably associated with specific disease mechanisms, including chronic inflammation and hypoxia. Nevertheless, evidence supporting a complete EMT of neoplastic cholangiocytes into stromal cells is lacking, and the gain of EMT-like changes by CCA cells rather reflects a shift towards an enhanced pro-invasive phenotype, likely induced by the tumor stroma. This concept may help to identify new biomarkers of early metastatic behavior along with potential therapeutic targets.
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900 Monza, Italy. s.brivio3@campus.unimib.it.
authors.forename: Simone
authors.initials: S
authors.lastname: Brivio
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900 Monza, Italy. massimiliano.cadamuro@gmail.com.|Department of Molecular Medicine, University of Padua School of Medicine, Viale Colombo 3, 35131 Padua, Italy. massimiliano.cadamuro@gmail.com.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Cadamuro
authors.affiliation: Department of Molecular Medicine, University of Padua School of Medicine, Viale Colombo 3, 35131 Padua, Italy. luca.fabris@unipd.it.|Liver Center, Section of Digestive Diseases, Yale University, TAC Building, 333 Cedar Street, New Haven, CT 06520, USA. luca.fabris@unipd.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Fabris
authors.affiliation: School of Medicine and Surgery, University of Milan-Bicocca, Via Cadore 48, 20900 Monza, Italy. mario.strazzabosco@yale.edu.|Liver Center, Section of Digestive Diseases, Yale University, TAC Building, 333 Cedar Street, New Haven, CT 06520, USA. mario.strazzabosco@yale.edu.
authors.forename: Mario
authors.initials: M
authors.lastname: Strazzabosco
keywords: cancer-associated fibroblast; cholangiocarcinoma; cholangiocyte; epithelial-to-mesenchymal transition; invasiveness; metastatization; tumor reactive stroma