Transformation of type 1 astrocytes with N-ethyl-N-nitrosourea: establishment of an in vitro system and the role of the p53 gene.
N-ethyl-N-nitrosourea (ENU)-induced gliomas, animal models of human gliomas, are most frequently oligodendrocytic, while human gliomas tend to be astrocytic. To facilitate a detailed study of human glial carcinogenesis, we developed an in vitro system using type 1 astrocyte transformation with ENU. Type 1 astrocytes from fetal Wistar rat brain were treated by a single dose of ENU. Transformed colonies appeared 50 days after exposure to single doses of ENU greater than 150 micrograms/mL. Cloned cells from these colonies retained the immunohistochemical characteristics of type 1 astrocytes. They showed rapid growth and high saturation densities, colony formation in low (2%) serum medium and gave rise to tumors when injected into nude mice. When p53 expression was studied at each passage, a single cell positive for mutant p53 protein emerged 40 days after ENU treatment. In the next 1-3 passages, the mutant p53 positive cell formed piled-up colonies and exhibited dominant growth. Northern blot analysis showed markedly increased accumulations of p53 mRNA in transformed cells. This in vitro transformation system of type 1 astrocytes provides a valuable tool for further investigations of astrocyte carcinogenesis.
Hiraga
S
S
Department of Neurosurgery, Osaka University Medical School, Japan.
Arita
N
N
Ohnishi
T
T
Izumoto
S
S
Taki
T
T
Yamamoto
H
H
Higuchi
M
M
Hayakawa
T
T
D000818:Animals; D001253:Astrocytes / Q000187:drug effects*; D001921:Brain / Q000166:cytology / Q000196:embryology; D002455:Cell Division; D002461:Cell Line, Transformed / Q000637:transplantation; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D004249:DNA Damage; D005038:Ethylnitrosourea / Q000633:toxicity*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D016158:Genes, p53; D005910:Glioma; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009368:Neoplasm Transplantation; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D014410:Tumor Stem Cell Assay; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
D009363:Neoplasm Proteins; D012334:RNA, Neoplasm; D016159:Tumor Suppressor Protein p53; D005038:Ethylnitrosourea