Over expression of proto-oncogenes: ki-ras, fos and myc in rat liver cells treated in vitro by two liver tumor promoters: phenobarbital and biliverdin.
Among the liver cell strains established in the laboratory from the liver of 10-day-old rats, some of them (FV) underwent spontaneous neoplastic transformation after a number of subcultures. However, one (Cl3) had maintained a non-transformed phenotype (persistence of contact inhibition, lack of growth in soft agar and of gamma glutamyltranspeptidase activity). These cells were grown either for a short time (48 h) or a longer time (3 weeks) in the presence of two liver tumor promoters: phenobarbital (0.2 x 10(-3) M) or biliverdin (10(-6) M). Total RNA was analysed by dot blot and Northern blot, then hybridized with ki-ras, fos and myc probes, previously labelled with 32P by nick translation. The three oncogenes were well expressed by the two strains but while an over-expression was observed for the Cl3 non-transformed cells when they were grown in presence of phenobarbital or biliverdin, the FV-transformed cells were not sensitive to the two promoters.
Lafarge-Frayssinet
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Laboratoire de Pathologie cellulaire de l'ER 278 (Réseau de Toxicologie nutritionnelle MRES), Institut de Recherches Scientifiques sur le Cancer, Villejuif, France.
Frayssinet
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D000818:Animals; D001663:Bilirubin / Q000031:analogs & derivatives*; D001664:Biliverdine / Q000494:pharmacology*; D002460:Cell Line; D011905:Genes, ras; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced; D010634:Phenobarbital / Q000494:pharmacology*; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344
D012333:RNA, Messenger; D001664:Biliverdine; D001663:Bilirubin; D010634:Phenobarbital