title: Reduced expression of the Rassf1a gene and its aberrant DNA methylation in pancreatic duct adenocarcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters.
abstract: Alterations of the Rassf1a gene were investigated in pancreatic duct adenocarcinomas (PDAs) induced by N-nitrosobis(2-oxopropyl)amine (BOP) in hamsters. Female Syrian golden hamsters received 70 mg/kg BOP, followed by repeated exposures to an augmentation pressure regimen consisting of a choline-deficient diet combined with a sequential course of DL-ethionine, L-methionine, and 20 mg/kg BOP. A total of 15 PDAs were obtained, and total RNAs were assessed by real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR). Expression of the Rassf1a was significantly reduced in PDAs (P < 0.005) compared with normal pancreatic tissues. For analysis of methylation status, bisulfite sequencing was performed. Normal tissues were all unmethylated in the 5' upstream region of Rassf1a. In contrast, four PDAs were highly methylated, correlating with reduced expression of the Rassf1a gene. Using reverse transcription (RT)-polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis, mutations were detected in 3 out of 15 PDAs (20%). These results suggested that alterations of the Rassf1a gene may be involved in development of PDAs induced by BOP in hamsters.
authors.affiliation: Department of Life Science, Laboratory of Cancer Biology and Bioinformatics, Faculty of Science and Engineering, Kinki University, Kowakae, Higashiosaka, Osaka, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Shimizu
authors.forename: Yumi
authors.initials: Y
authors.lastname: Itsuzaki
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Fujii
authors.forename: Kanya
authors.initials: K
authors.lastname: Honoki
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Tsujiuchi
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002273:Carcinogens / Q000633:toxicity*; D006224:Cricetinae; D019175:DNA Methylation; D017931:DNA Primers; D005260:Female; D008647:Mesocricetus; D009602:Nitrosamines / Q000633:toxicity*; D010190:Pancreatic Neoplasms / Q000139:chemically induced / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D002273:Carcinogens; D017931:DNA Primers; D009602:Nitrosamines; D025521:Tumor Suppressor Proteins; C013622:nitrosobis(2-oxopropyl)amine