Analysis of c-Ha-ras gene mutations in skin tumors induced in carcinogenesis-susceptible and carcinogenesis-resistant mice by different two-stage protocols or tumor promoter alone.
In the present study we describe the molecular analysis of c-Ha-ras gene mutations in 47 papillomas and 17 carcinomas developed in two lines of mice, carcinogenesis-susceptible (Car-S) and carcinogenesis-resistant (Car-R), selectively bred for extreme susceptibility or resistance to chemical skin carcinogenesis initiated and promoted with different doses of 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). This study also presents the analysis of c-Ha-ras gene mutations in 22 papillomas and 22 carcinomas in Car-S mice initiated with DMBA and promoted with benzoyl peroxide (BzPo) and in seven papillomas and one carcinoma from a group of uniniated Car-S mice that received only BzPo treatment. The data showed that a A(182)-->T transversion in the c-Ha-ras gene was present in 100% and 81% of the skin tumors developed in Car-S and Car-R mice, respectively, after DMBA initiation and TPA promotion, suggesting that differences in genetic susceptibility can influence the frequency of c-Ha-ras mutations in the skin tumors produced. The same A(182)-->T mutation with an incidence of 68% was found in papillomas from DMBA-initiated and BzPo-promoted Car-S mice. The difference in the mutation frequency between DMBA/BzPo and DMBA/TPA papillomas suggested that the promotion step contributes to the final mutation pattern. The tumor induction experiment with BzPo alone showed that this compound can induce tumor development in 26% of Car-S mice, and the molecular analysis of the tumors showed a broad mutation spectrum, including mutations in codons 12, 13, and 61 of the c-Ha-ras gene. Mol. Carcinog. 30:111-118, 2001.
Pazzaglia
S
S
Division of Protection of Man and Ecosystems, ENEA CR-Casaccia, Rome, Italy.
Mancuso
M
M
Primerano
B
B
Rebessi
S
S
Biozzi
G
G
Covelli
V
V
Saran
A
A
D000818:Animals; D001551:Benz(a)Anthracenes / Q000633:toxicity; D001585:Benzoyl Peroxide / Q000633:toxicity; D002273:Carcinogens / Q000633:toxicity*; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D019008:Drug Resistance, Neoplasm; D011905:Genes, ras / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation; D010212:Papilloma / Q000139:chemically induced / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000139:chemically induced / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity
D001551:Benz(a)Anthracenes; D002273:Carcinogens; D017931:DNA Primers; C046810:7,12-dihydroxymethylbenz(a)anthracene; D013755:Tetradecanoylphorbol Acetate; D001585:Benzoyl Peroxide