Oncogene alterations in in vitro transformed rat tracheal epithelial cells.
10 derivations of rat tracheal epithelial (RTE) cells, including normal cells, normal primary cultures, 7 tumorigenic cell lines and 1 nontumorigenic cell line transformed in vitro by treatment with 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene (BP) and/or 12-O-tetradecanoylphorbol-13-acetate (TPA) were examined for oncogene alterations. No abnormalities of Ha-ras or Ki-ras were seen that were suggestive of amplification, rearrangement or the presence of RFLPs. Analysis of specific-point mutations in Ha-ras using Pst I digestion (codon 12, GGA to GCA) or Ha-ras and Ki-ras using Xba I (codon 61, CAA to CTA) were negative. In one cell line derived by DMBA treatment, changes in the c-myc restriction digest pattern were seen after incubation with Bam HI and Hind III. Northern analysis revealed consistent differences between normal and transformed cells when probed with Ha-ras; c-myc expression was of low intensity, and the expression of Ki-ras could not be detected. Transfection of RTE cell DNAs into NIH/3T3 cells did not result in the appearance of morphologic transformants. The studies suggest that Ha-ras or Ki-ras codon 61 A to T transversions (CAA to CTA) are not associated with the immortal/tumorigenic phenotype in RTE cells transformed by DMBA or TPA, and are in contrast to results reported in some other biological systems.
Carcinogenesis and Metabolism Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.
M J
MJ
Mass
N S
NS
Schorschinsky
J A
JA
Lasley
D K
DK
Beeman
S J
SJ
Austin
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D015152:Blotting, Northern; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D004247:DNA / Q000187:drug effects / Q000235:genetics*; D004848:Epithelium; D005784:Gene Amplification; D015321:Gene Rearrangement; D011905:Genes, ras / Q000235:genetics*; D008297:Male; D009693:Nucleic Acid Hybridization; D015689:Oncogene Protein p21(ras) / Q000235:genetics; D009857:Oncogenes / Q000187:drug effects / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D012313:RNA / Q000187:drug effects / Q000235:genetics; D051381:Rats; D013755:Tetradecanoylphorbol Acetate; D014132:Trachea / Q000166:cytology; D014162:Transfection
D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D015127:9,10-Dimethyl-1,2-benzanthracene; D012313:RNA; D004247:DNA; D015689:Oncogene Protein p21(ras); D013755:Tetradecanoylphorbol Acetate