Reference SummaryRumsby PC, Carcinogenesis 1991 Dec;12(12):2331-6
Title |
Analysis of the Ha-ras oncogene in C3H/He mouse liver tumours derived spontaneously or induced with diethylnitrosamine or phenobarbitone. |
Authors |
Rumsby PC; Barrass NC; Phillimore HE; Evans JG |
Journal |
Carcinogenesis |
Volume |
12 |
Issue |
12 |
Year |
1991 |
Pages |
2331-6 |
Abstract |
In a study of the mechanisms involved in the induction of tumours by chemicals, the Ha-ras oncogene was analysed in liver tumours induced by the genotoxic carcinogen diethylnitrosamine (DEN), or the non-genotoxic agent phenobarbitone (PB) in C3H/He mice. Mutations were detected using the polymerase chain reaction and oligonucleotide hybridization. Codon 61 mutations were detected in 41% of DEN-induced tumours (19/46), either in the first base (CG----AT, 12/19), a transversion, or the second base (AT----GC, 7/19), a transition. Codon 61 mutations were also found in 29% of spontaneous tumours (all CG----AT, 6/21) but none were detected in PB-induced tumours (0/15) or in normal liver tissue of untreated mice (0/30). No mutations were detected at codon 12. Low and variable expression of the Ha-ras gene was detected in all liver tissues with moderately raised levels (175-200%) in spontaneous, DEN and PB-induced tumours as compared to normal liver tissue. The H-ras gene was methylated to some extent in all liver tissues, with no discernible difference between the treatments. The frequency of the Ha-ras mutation at codon 61 in DEN-induced tumours is greater than in spontaneously arising tumours. This increase is not accompanied by any specific alteration in the expression or methylation of the gene. Since PB-induced tumours do not possess mutations in the Ha-ras gene at codons 12 or 61, the data suggest that the non-genotoxic agent PB induces tumours in the C3H/He mouse liver with a mechanism distinct from that of spontaneous tumours or those that result from treatment with a potent genotoxic carcinogen such as DEN. |
Links |
J:1781 – MGI References 1747936 – National Library of Medicine/PubMed |
Strain | Model Name | Treatment Agent(s) | Organ Affected | Frequency | Model Details |
---|---|---|---|---|---|
C3H/He | Liver tumor - basophilic | Liver |
observed |
||
C3H/He | Liver tumor - basophilic |
|
Liver |
observed |
|
C3H/He | Liver tumor - eosinophilic |
|
Liver |
observed |