We found chemoradiation-resistant pancreatic cancer cells to be similar to CSCs and to undergo EMT, suggesting that chemoradiation resistance-induced EMT is linked to CSC generation.

Background:The multidrug resistance and distant metastasis of cholangiocarcinoma result in high postoperative recurrence and low long-term survival rates. It has been demonstrated that the ectopic expression of miR-200 suppresses the multidrug resistance and metastasis of cancer. However, the expression and function of miR-200 in cholangiocarcinoma has not yet been described.Methods:In this study, we identified dysregulated microRNAs (miRNAs, miR) in cholangiocarcinoma tissue by microarray analysis, and subsequent real-time PCR and northern blot analyses validated the expression of candidate miR. We performed functional analyses and investigated the relationship between miR-200b/c expression and the properties of cholangiocarcinoma cells. A dual luciferase assay was applied to examine the effect of miRNAs on the 3′-UTR of target genes, and we demonstrated the function of the target gene by siRNA transfection identifying the downstream pathway via western blotting.Results:We found significantly downregulated expression of four miR-200 family members (miR-200a/b/c/429) and then confirmed that ectopic miR-200b/200c inhibits the migration and invasion of cholangiocarcinoma cells both in vitro and in vivo. We found that miR-200b/c influenced the tumourigenesis of cholangiocarcinoma cells including their tumour-initiating capacity, sphere formation, and drug resistance. We further found that miR-200b/c regulated migration and invasion capacities by directly targeting rho-kinase 2 and regulated tumorigenic properties by directly targeting SUZ12 (a subunit of a polycomb repressor complex).Conclusion:Our study shows that miR-200b/c has a critical role in the regulation of the tumorigenic and metastatic capacity of cholangiocarcinoma and reveals the probable underlying mechanisms.

Recent studies suggest that the ability to form and grow tumors specifically resides in a small cell population called cancer stem cells (CSCs). These studies were conducted mainly on various human cancers; however, isolation and characterization of stem cells from cholangiocarcinoma have not been attempted. The molecular markers CD24, CD44, CD34, and epithelial cell adhesion molecule (EpCAM) are widely used, individually or in combination, to characterize some types of CSCs. In this study, we used these markers to identify a subpopulation of cells in extrahepatic cholangiocarcinoma (ECC) with cancer stem/progenitor cell-like properties. We found that CD241 CD44 Extrahepatic cholangiocarcinoma (ECC), including perihilar and distal biliary tree carcinomas, is notoriously difficult to diagnose and treat, and is associated with extensive local tumor invasion, multidrug resistance and high mortality. 1,2 Despite advances in surgical and medical therapy, its survival rates have not improved significantly over recent decades. 3 Recent data suggest that cancer stem cells (CSCs) are critical for tumor initiation, progression and persistence, and metastasis.