Establishment and characterization of a novel human cholangiocarcinoma cell line with high metastatic activity.

Cholangiocarcinoma (CCA) is a highly metastatic tumor, and the lung is a common site of metastasis. A greater understanding of the biology of metastases is needed to improve treatment outcomes. Herein, a highly metastatic human CCA subline, KKU-213L5 from an original cell line, KKU-213 that has marginally metastatic ability, was established and characterized. KKU-213L5 was selected in vivo through the fifth serial passage of pulmonary metastasized tissues via tail-vein injection in NOD/scid/Jak3 mice. The metastatic abilities of the KKU-213L5 cells were compared with the parental line in vitro and in vivo. The expression profile of this metastatic cell line was determined using real-time PCR. KKU-213L5 cells were found to possess higher metastatic phenotypes, i.e., growth rates, stem cell surface markers (CD133), migration and invasion characteristics when compared with the parental cells. Compared to the KKU-213 cells, KKU-213L5 cells formed larger tumors in subcutaneous xenografted mice and had a >10-fold increase in lung metastases in the tail-vein injected metastatic mouse model. Mice injected intravenously with KKU-213L5 cells had a significantly shorter survival. Analysis of the expressed genes related to progression of cancer revealed significant upregulation of anterior gradient protein-2 (AGR2) and suppression of KiSS-1 in the KKU-213L5 cells. The association of these two genes with metastasis was affirmed in CCA patient tissues since increased AGR2 expression and decreased KiSS-1 expression were found in higher stage patient tumors. In conclusion, a highly metastatic human CCA cell line was established and characterized. It is plausible that the differential expression between the parental KKU-213 and highly metastatic KKU-213L5 cells may be beneficial to classify novel genes associated with metastasis. The KKU-213L5 cell line should serve as a valued device for discovering the molecular mechanisms of CCA metastasis and enabling the search for an effective therapy for the unmet clinical need in CCA.