ABSTRACT
Krüppel-like factor 8 (KLF8) is highly expressed in hepatocellular carcinoma (HCC) and contributes to tumor initiation and progression by promoting HCC cell proliferation and invasion. However, the role of KLF8 in liver cancer stem cells (LCSCs) is not known. In the current study, we investigated the role of KLF8 in LCSCs to determine if KLF8 is a novel marker of these cells. We found that KLF8 was highly expressed in primary HCC tumors, distant migrated tissues, and LCSCs. Patients with high KLF8 expression had a poor prognosis. KLF8 promoted stem cell-like features through activation of the Wnt/ß-catenin signaling pathway. Cell apoptosis was significantly increased in HCC cells with knockdown of KLF8 compared with the control cells when treated with the same doses of sorafenib or cisplatin. Taken together, our study shows that KLF8 plays a potent oncogenic role in HCC tumorigenesis by maintaining stem cell-like features through activation of the Wnt/ß-catenin signaling pathway and promoting chemoresistance. Thus, targeting KLF8 may provide an effective therapeutic approach to suppress tumorigenicity of HCC. © 2016 Wiley Periodicals, Inc.
Subject(s)
Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Liver/pathology , Neoplastic Stem Cells/pathology , Repressor Proteins/metabolism , Wnt Signaling Pathway , Antineoplastic Agents/pharmacology , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Cell Line, Tumor , Cisplatin/pharmacology , Drug Resistance, Neoplasm , Gene Expression Regulation, Neoplastic , Humans , Kruppel-Like Transcription Factors , Liver/metabolism , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Neoplastic Stem Cells/metabolism , Niacinamide/analogs & derivatives , Niacinamide/pharmacology , Phenylurea Compounds/pharmacology , Prognosis , Repressor Proteins/analysis , Repressor Proteins/genetics , Sorafenib , Wnt Proteins/metabolismABSTRACT
BACKGROUND/AIMS: MicroRNAs (miRNAs) play critical roles during carcinogenesis and cancer progression. Down-regulation of miR-204 has been frequently observed in various cancers. In this study, we investigated the roles and mechanisms of miR-204 in human intrahepatic cholangiocarcinoma (ICC). METHODS: The relative expression of miR-204 in ICC tissues and cell lines was monitored by qRT-PCR. Effects of miR-204 were studied in human ICC cell lines HuH28 and HuCCT1, and cells were analyzed for proliferation, migration and invasion. Expression levels of miR-204 target gene Slug and EMT markers (E-cadherin and vimentin) in ICC cell lines and tissues were measured by qRT-PCR, western blotting and immunofluorescence. RESULTS: miR-204 was frequently downregulated in human ICC, and the low-level expression of miR-204 was significantly associated with lymph node metastasis. Overexpression of miR-204 dramatically suppressed ICC cell migration and invasion, as well as the epithelial-mesenchymal transition process (EMT). Slug was identified as a direct target of miR-204, and its downregulation by miR-204 in HuH28 cells reversed EMT, as shown by the increased expression of the epithelial marker E-cadherin and decreased expression of the mesenchymal marker vimentin. CONCLUSION: These findings suggest that miR-204 plays negative roles in the invasive and/or metastatic potential of ICC, and that its suppressive effects are mediated by repressing Slug expression.
