Hepatology (Baltimore, Md.)
It has been established that microRNA expression and function contribute to phenotypic features of malignant cells, including resistance to apoptosis. Although targets and functional roles for a number of microRNAs have been described in cholangiocarcinoma, many additional microRNAs dysregulated in this tumor have not been assigned functional roles. In this study, we identify elevated miR-25 expression in malignant cholangiocarcinoma cell lines as well as patient samples. In cultured cells, treatment with the Smoothened inhibitor, cyclopamine, reduced miR-25 expression, suggesting Hedgehog signaling stimulates miR-25 production. Functionally, miR-25 was shown to protect cells against TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Correspondingly, antagonism of miR-25 in culture sensitized cells to apoptotic death. Computational analysis identified the TRAIL Death Receptor-4 (DR4) as a potential novel miR-25 target, and this prediction was confirmed by immunoblot, cell staining, and reporter assays.
CONCLUSION: These data implicate elevated miR-25 levels in the control of tumor cell apoptosis in cholangiocarcinoma. The identification of the novel miR-25 target DR4 provides a mechanism by which miR-25 contributes to evasion of TRAIL-induced cholangiocarcinoma apoptosis.
3' Untranslated Regions, Apoptosis, Bile Duct Neoplasms, Bile Ducts, Intrahepatic, Cell Line, Tumor, Cholangiocarcinoma, Gene Expression Regulation, Hedgehog Proteins, Humans, MicroRNAs, Receptors, TNF-Related Apoptosis-Inducing Ligand, Signal Transduction
This is the peer reviewed version of the following article: 39. Razumilava N, Bronk SF, Smoot RL, Fingas CD, Werneburg NW, Roberts LR, Mott JL*. (2012) miR-25 Targets TRAIL Death Receptor-4 and Promotes Apoptosis Resistance in Cholangiocarcinoma. Hepatology 55(2):465-75, which has been published in final form at 10.1002/hep.24698. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving
Razumilava, Nataliya; Bronk, Steve F.; Smoot, Rory L.; Fingas, Christian D.; Werneburg, Nathan W.; Roberts, Lewis R.; and Mott, Justin L., "miR-25 targets TNF-related apoptosis inducing ligand (TRAIL) death receptor-4 and promotes apoptosis resistance in cholangiocarcinoma." (2012). Journal Articles: Biochemistry & Molecular Biology. 19.