title: Possible enhancing activity of diacylglycerol on 4-nitroquinoline 1-oxide induced carcinogenesis of the tongue in human c-Ha-ras proto-oncogene transgenic rats.
abstract: 1,2-diacylglycerol (1,2-DAG) is involved in cell proliferation as an activator of protein kinase C (PKC) and has been shown to stimulate growth of cancer cells, raising the possibility of a role in tumor promotion. Ingested DAG oil, containing 70% 1,3-DAG and 30% 1,2-DAG, is digested and considered to be safe as edible oil. However, DAG may directly contact with oral cavity mucosa in undigested form. The present study was conducted to examine the effects of DAG oil on carcinogenesis in c-Ha-ras proto-oncogene transgenic (Tg) rats administered 4-nitroquinoline 1-oxide (4NQO, 10 ppm) in their drinking water for 10 weeks for initiation of mainly upper digestive organs. DAG oil added in basal diet at 5.5%, 2.75%, 1.38% and 0% with total fat made up to 5.5% with triacylglycerol (TAG) was administered during the initiation and post-initiation period. The study was terminated at week 12 (Tg females) and 20 (Tg males, wild females and males). The fatty acid composition of DAG oil was similar to TAG (linoleic acid 46.6% and oleic acid 38.9%). In Tg male rats, DAG oil administration was associated with significant increase (P<0.05) in the incidence of squamous cell carcinomas (SCC) of the tongue (5.5% DAG, 43.8%; 2.75% DAG, 20%; 1.38% DAG, 14.3%; 0%, 12.3%) with the Cochran-Armitage trend test and also number of tumors in coefficients for linear contrast trend tests. Tongue SCC induction of wild males and all females was not significant. The present results suggest that DAG oil may have enhancing and/or promotion potential for tongue carcinogenesis in male Tg featuring elevated ras expression.
authors.affiliation: Department of Molecular Toxicology, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan. htsuda@med.nagoya-cu.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Iigo
authors.forename: Nobuo
authors.initials: N
authors.lastname: Takasuka
authors.forename: Shinobu
authors.initials: S
authors.lastname: Ueda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Katsumi
authors.initials: K
authors.lastname: Fukamachi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Shirai
authors.forename: Sachiko
authors.initials: S
authors.lastname: Hirano
authors.forename: Eiji
authors.initials: E
authors.lastname: Matsuda
authors.forename: Keiji
authors.initials: K
authors.lastname: Wakabayashi
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology*; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D030801:Animals, Genetically Modified; D001219:Aspartate Aminotransferases / Q000097:blood; D002273:Carcinogens / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology; D002784:Cholesterol / Q000097:blood; D004075:Diglycerides / Q000494:pharmacology*; D004357:Drug Synergism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D011905:Genes, ras; D006651:Histocytochemistry; D006801:Humans; D008074:Lipoproteins / Q000097:blood; D008297:Male; D000090063:Proto-Oncogene Mas; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014062:Tongue Neoplasms / Q000097:blood / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology; D014280:Triglycerides / Q000097:blood
chemical_list: C011439:1,2-diacylglycerol; D002273:Carcinogens; D004075:Diglycerides; D005230:Fatty Acids, Nonesterified; D008074:Lipoproteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D014280:Triglycerides; D015112:4-Nitroquinoline-1-oxide; D002784:Cholesterol; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase