PURPOSE: The susceptibility of male p53 nullizygote (-/-), heterozygote (+/-), and wild-type (+/+) mice to 1,2-dimethylhydrazine (DMH) induction of colon carcinogenesis was investigated. METHODS: In a preliminary short-term experiment, male mice of three genotypes were given s.c. of 20 mg/kg DMH once weekly for 5 weeks. In a medium-term experiment, mice were given weekly s.c. of DMH for 15 weeks. In a long-term experiment, male p53 (+/-) and (+/+) mice were given weekly injections of DMH for 15 weeks, and killed at week 30. RESULTS: In the medium-term experiment, carcinomas were observed in 70% of p53 (-/-) mice, although there were no carcinomas in p53 (+/+) and (+/-) mice. In the long-term experiment, there was no significant difference in incidences of adenomas and carcinomas between p53 (+/+) and (+/-) mice. PCR-single strand conformation polymorphism analysis of exons 5-8 of p53 gene revealed four mutations in one focal atypia, one adenoma, and two carcinomas, out of 56 colonic proliferative lesions in the medium- and long-term experiments. CONCLUSIONS: These results suggest that p53 might not be a direct target of DMH but complete loss of p53 might elevate susceptibility to DMH-induced colorectal carcinogenesis.
PURPOSE: The susceptibility of male p53 nullizygote (-/-), heterozygote (+/-), and wild-type (+/+) mice to 1,2-dimethylhydrazine (DMH) induction of colon carcinogenesis was investigated. METHODS: In a preliminary short-term experiment, male mice of three genotypes were given s.c. of 20 mg/kg DMH once weekly for 5 weeks. In a medium-term experiment, mice were given weekly s.c. of DMH for 15 weeks. In a long-term experiment, male p53 (+/-) and (+/+) mice were given weekly injections of DMH for 15 weeks, and killed at week 30. RESULTS: In the medium-term experiment, carcinomas were observed in 70% of p53 (-/-) mice, although there were no carcinomas in p53 (+/+) and (+/-) mice. In the long-term experiment, there was no significant difference in incidences of adenomas and carcinomas between p53 (+/+) and (+/-) mice. PCR-single strand conformation polymorphism analysis of exons 5-8 of p53 gene revealed four mutations in one focal atypia, one adenoma, and two carcinomas, out of 56 colonic proliferative lesions in the medium- and long-term experiments. CONCLUSIONS: These results suggest that p53 might not be a direct target of DMH but complete loss of p53 might elevate susceptibility to DMH-induced colorectal carcinogenesis.
Authors: M Yamamoto; T Tsukamoto; H Sakai; N Shirai; H Ohgaki; C Furihata; L A Donehower; K Yoshida; M Tatematsu Journal: Carcinogenesis Date: 2000-10 Impact factor: 4.944
Authors: M Tatematsu; T Masui; H Fukami; M Yamamoto; H Nakanishi; K Inada; M Kusakabe; T Sakakura Journal: Int J Cancer Date: 1996-04-10 Impact factor: 7.396
Authors: Richard B Halberg; Xiaodi Chen; James M Amos-Landgraf; Alanna White; Kristin Rasmussen; Linda Clipson; Cheri Pasch; Ruth Sullivan; Henry C Pitot; William F Dove Journal: Genetics Date: 2008-08-24 Impact factor: 4.562