Methylnitrosourea-induced tumorigenesis in MGMT gene knockout mice

Kunihiko Sakumi, Akiko Shiraishi, Seiichiro Shimizu, Teruhisa Tsuzuki, Takatoshi Ishikawa, Mutsuo Sekiguchi

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124 Citations (Scopus)


Gene targeting was used to obtain mice defective in the MGMT gene, encoding O6-methylguanine-DNA methyltransferase Tsuzuki et al., Carcinogenesis (Lond), 17: 1215-1220, 1996]. These MGMT(-/-) mice were most sensitive to the alkylating carcinogen, methylnitrosourea; when varied doses of methylnitrosourea were administered to 6-week-old mice and survivals at the 30th day were determined, LD50s of MGMT(-/-) and MGMT(+/+) mice were 20 and 240 mg/kg of body weight, respectively. MGMT(+/-) mice were as resistant as MGMT(+/+) mice, but some difference in survival time was noted when the two genotypes of mice were exposed to a relatively high dose of methylnitrosourea. A large number of thymic lymphomas, as well as lung adenomas, occurred in MGMT(-/-) mice exposed to methylnitrosourea at a dose of 2.5 mg/kg of body weight. In case of exposure to the same dose of drug, no or few tumors occurred in the MGMT(+/+) and MGMT(+/-) mice. It appears that the DNA repair methyltransferase protein protected these mice from methylnitrosourea-induced tumorigenesis.

Original languageEnglish
Pages (from-to)2415-2418
Number of pages4
JournalCancer Research
Issue number12
Publication statusPublished - Jun 15 1997

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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