title: DNA methyltransferase inhibitor zebularine induces human cholangiocarcinoma cell death through alteration of DNA methylation status.
abstract: Cholangiocarcinoma (CCA) is a cancer arising from the neoplastic transformation of cholangiocytes. During tumorigenesis, tumor suppressor and cancer-related genes are commonly silenced by aberrant DNA methylation in their promoter regions. Zebularine (1-(β-D-ribofuranosyl)-1,2-dihydropyrimidin-2-one) acts as an inhibitor of DNA methylation and exhibits chemical stability and minimal cytotoxicity both in vitro and in vivo. In this study, we explore the effect and possible mechanism of action of zebularine on CCA cells. We demonstrate that zebularine exerts an antitumor effect on CCA cells. Zebularine treatment decreased the concentrations of DNA methyltransferase (DNMT) proteins, and DNMT1 knockdown led to apoptotic cell death in the CCA cell lines TFK-1 and HuCCT1. DNA methylation analysis demonstrated that zebularine induced DNA demethylation, and the GO Biological Process terms "hemophilic cell adhesion", "regulation of transcription, DNA-dependent" and "Wnt signaling pathway" were found to be significantly enriched in association with demethylated genes. Furthermore, we observed that zebularine treatment decreased β-catenin protein levels in TFK-1 and HuCCT1 cells. These results suggest that zebularine alters DNA methylation status, and that some aspect of DNA demethylation by zebularine induces suppression of the Wnt signaling pathway, which leads to apoptotic cell death in CCA. We previously reported a novel mechanism of zebularine-induced cell growth arrest and apoptosis in hepatocellular carcinoma via a DNA methylation-independent pathway. Together, our present and previous studies indicate that zebularine could function as both a DNMT inhibitor and a non-DNMT inhibitor reagent, and that, while the optimal usage of zebularine may depend on cancer type, zebularine may be useful for chemotherapy against cancer.
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Kazuaki
authors: K
authors: Nakamura
authors: Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Kazuhiko
authors: K
authors: Nakabayashi
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Kyaw
authors: K
authors: Htet Aung
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Kazuko
authors: K
authors: Aizawa
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Naoko
authors: N
authors: Hori
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Junji
authors: J
authors: Yamauchi
authors: Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Kenichiro
authors: K
authors: Hata
authors: Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan.
authors: Akito
authors: A
authors: Tanoue
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001650:Bile Duct Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000473:pathology*; D018899:CpG Islands / Q000235:genetics; D003562:Cytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors* / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D019175:DNA Methylation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006801:Humans; D015854:Up-Regulation / Q000187:drug effects; D060449:Wnt Signaling Pathway / Q000187:drug effects; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D051176:beta Catenin; D003562:Cytidine; C009131:pyrimidin-2-one beta-ribofuranoside; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human