Methionine-independence, tumorigenicity and oncogene expression of rat hepatocarcinoma cells.
Methionine-dependent (Met-Hcy+) revertant sublines were isolated from a methionine-independent (Met+Hcy-) rat hepatocarcinoma cell line (LF). Characterization of these sublines has shown that long-term culture in methionine-deprived medium significantly decreases their ability to grow in vitro, their tumorigenicity in new-born syngeneic animals and their level of transcription of 3 oncogenes (c-Ki-ras, c-Ha-ras, c-myc) involved in hepatic growth. These data strongly support a relationship between methionine-dependence and ability to grow in vivo as tumors. A shift in methionine-supplemented medium for several cell generations of the various sublines grown in methionine deprived medium, has revealed that under these conditions, the cells maintain a diminished in vitro growth and tumorigenic capacity, despite an increased transcription of c-Ki-ras, c-Ha-ras and c-myc. This points out the complexity of the relationship between the level of activity of some oncogenes and the expression of the malignant phenotypes.
Cassingena
R
R
Laboratoires de Génétique cellulaire, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France.
Lafarge-Frayssinet
C
C
Painchault
V
V
Estrade
S
S
Nardeux
P
P
Frayssinet
C
C
D000818:Animals; D000831:Animals, Newborn; D002455:Cell Division; D003470:Culture Media; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D008715:Methionine / Q000096:biosynthesis / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D014407:Tumor Cells, Cultured; D004124:p-Dimethylaminoazobenzene
D003470:Culture Media; D012333:RNA, Messenger; D004124:p-Dimethylaminoazobenzene; D008715:Methionine