title: Analysis of gene expression profiles of forestomach tumors in rasH2 mice initiated with N-ethyl-N-nitrosourea.
abstract: To clarify the mechanisms underlying enhancement of carcinogenesis in transgenic mice carrying a human prototype c-Ha- ras gene (rasH2 mouse), animals received a single intraperitoneal injection of 120 mg/kg N-ethyl-N-nitrosourea (ENU) and at 20 weeks thereafter expression profiles in three induced forestomach squamous cell carcinomas were assessed using high-density oligonucleotide microarrays. In addition, the reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to assess mRNA expression of human c-Ha- ras gene and some molecules involved in the Ras-regulated mitogen-activated protein kinase (MAPK) pathway. Compared with normal forestomach tissue from control mice, 416 and 368 genes, respectively, were found to be commonly up- and down-regulated by 2-fold or more in the three tumors. Many genes involved in tumor invasion and metastasis such as transforming growth factor beta1 and matrix metalloproteinases were up-regulated, reflecting tumor progression. RT-PCR analysis confirmed up-regulation of transgene, mouse endogenous Ha- ras, N- ras, raf, Mekk2, c- fos, junB, c- myc and cyclin D1. These results suggest that activation of the Ras-MAPK cascade following up-regulation of both human and mouse endogenous ras genes is involved in the enhanced tumorigenesis of ENU-induced forestomach squamous cell carcinomas in rasH2 mice.
authors.affiliation: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, 183-8509, Tokyo, Japan. mokamura@cc.tuat.ac.jp
authors.forename: Miwa
authors.initials: M
authors.lastname: Okamura
authors.forename: Kayo
authors.initials: K
authors.lastname: Sumida
authors.forename: Tomoko
authors.initials: T
authors.lastname: Muto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kashida
authors.forename: Noboru
authors.initials: N
authors.lastname: Machida
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Mitsumori
mesh_terms: D000818:Animals; D005038:Ethylnitrosourea / Q000633:toxicity*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology
chemical_list: D005038:Ethylnitrosourea