ABSTRACT: Chemotherapy resistance is a relevant clinical issue in the tumor treatment, in particular in biliary tract carcinoma (BTC), for which there are no effective therapies, neither in the first nor in the second line. The development of chemoresistant cell lines as experimental models to investigate the mechanisms of resistance and identify alternative druggable pathways is mandatory. In BTC, in which genetics and biological behavior depend on the etiology, ethnicity and anatomical site of origin, the creation of models that better recapitulate these characteristics is even more crucial. Here we have established and characterized an intrahepatic cholangiocarcinoma (iCCA) cell line derived from an Italian patient, called 82.3. Cells were isolated from a patient-derived xenograft and, after establishment, immunophenotypic, biological, genetic, molecular characteristics and tumorigenicity in vivo in NOD/SCID mice were investigated. 82.3 cells exhibited epithelial morphology and cell markers (EPCAM, CK7 and 19); they also expressed different cancer stem markers (CD44, CD133, CD49b, CD24, Stro1, PAX6, FOXA2, OCT3 / 4) and under anchorage-independent and serum-free conditions were capable of originating cholangiospheres. The population doubling time was approximately 53 hours. In vitro they demonstrated a poor ability to migrate, but in vivo, 82.3 cells retained their tumorigenicity, with a long latency period (16 weeks). Genetic identity using DNA fingerprinting analysis revealed 16 different loci and the cell line was characterized by a complex hyperdiploid karyotype. Furthermore, 82.3 cells showed cross-resistance to gemcitabine, 5-fluorouracil, carboplatin and oxaliplatin; in fact their genetic profile showed that in a panel of genes (n = 168), specific for drug resistance and related to the epithelial-mesenchymal transition, 60% of them were deregulated in 82.3 cells compared to a control iCCA cell line sensitive to chemotherapeutics. In conclusion, we have created new iCCA cell line of Caucasian origin that could be exploited as a preclinical model to study drug resistance mechanisms and to identify alternative therapies to improve the prognosis of this tumor type.
