title: Frequent loss of RUNX3 gene expression in human bile duct and pancreatic cancer cell lines.
abstract: RUNX3, a Runt domain transcription factor involved in TGF-beta signaling, is a candidate tumor-suppressor gene localized in 1p36, a region commonly deleted in a wide variety of human tumors, including those of the stomach, bile duct, and pancreas. Recently, frequent inactivation of RUNX3 has been demonstrated in human gastric carcinomas. In this study, to examine the involvement of RUNX3 abnormalities in tumorigenesis of bile duct as well as pancreatic cancers, we investigated not only the expression but also methylation status of RUNX3 in 10 human bile duct and 12 pancreatic cancer cell lines. Seven (70%) of the bile duct and nine (75%) of the pancreatic cancer cell lines exhibited no expression of RUNX3 by both Northern blot analysis and the reverse transcriptase polymerase chain reaction. All of the 16 cell lines that did not express RUNX3 also showed methylation of the promoter CpG island of the gene, whereas the six cell lines that showed RUNX3 expression were not methylated or only partially methylated in the RUNX3 promoter region. Moreover, treatment with the methylation inhibitor 5'-aza-2'-deoxycitidine activated RUNX3 mRNA expression in all of 16 cancer cell lines that originally lacked RUNX3 expression. Finally, hemizygous deletion of RUNX3, as detected by fluorescence in situ hybridization, was found in 15 of the 16 cancer cell lines that lacked RUNX3 expression. These data suggest that the inactivation of RUNX3 plays an important role in bile duct and pancreatic carcinogenesis, and that methylation is a common mechanism by which the gene is inactivated.
authors.affiliation: Department of Gastroenterology and Hepatology, Graduate School of Internal Medicine, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Wada
authors.forename: Shujiro
authors.initials: S
authors.lastname: Yazumi
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takaishi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Mitsutaka
authors.initials: M
authors.lastname: Sawada
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ida
authors.forename: Chouhei
authors.initials: C
authors.lastname: Sakakura
authors.forename: Kosei
authors.initials: K
authors.lastname: Ito
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ito
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Chiba
mesh_terms: D001483:Base Sequence; D001650:Bile Duct Neoplasms / Q000378:metabolism*; D050677:Core Binding Factor Alpha 3 Subunit; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics; D051901:Smad4 Protein; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D050677:Core Binding Factor Alpha 3 Subunit; D004268:DNA-Binding Proteins; D018125:Receptors, Transforming Growth Factor beta; C493729:Runx3 protein, human; C497796:SMAD4 protein, human; D051901:Smad4 Protein; D015534:Trans-Activators; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II