Related Experiment Video
Updated: Aug 8, 2026
Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 17, 2010
Evaluation of potential oncogene alterations in the ENU1564 rat mammary tumor model
Abstract:
The ENU1564 tumor line originated from a rat mammary tumor induced by N-ethyl-N-nitrosourea (ENU), an alkylating chemical carcinogen which induces genetic point mutations. The oncogene abnormalities in rat mammary tumors induced by ENU have not been characterized. In this study, two highly metastatic clones (Br7-C5 and FP2-All) derived from the adenocarcinoma cell line ENU1564, were evaluated for the presence of mutational activation involving the c-Ha-ras, c-neu, and p53 oncogenes. These oncogenes were chosen for investigation based upon their involvement in other ENU-induced rat tumors (c-neu in malignant schwannomas and p53 in nephro-blastomas) or in methylnitrosourea (MNU)-induced rat mammary tumors (c-Ha-ras). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence-specific oligonucleotide hybridization analyses indicated that no c-Ha-ras codon 12 mutation was present in these tumor cells. PCR-RFLP and single-stranded conformational polymorphism (PCR-SSCP) analyses showed that no sequence changes were present over a 138 base-pair gene fragment spanning codon 664 of the c-neu protooncogene (the site of point mutation in ENU-induced rat nerve tumors). Immunoprecipitation and Western immunoblotting indicated that the p53 protein is neither over-expressed nor mutated in the tumor cells. The results failed to identify specific oncogene alterations in the ENU1564 rat mammary tumor line but ruled out mutational activation of c-Ha-ras (codon 12), c-neu (codon 664), and the p53 genes.
Insights
This study investigated oncogene mutations in the ENU1564 rat mammary tumor line. Researchers found no alterations in c-Ha-ras, c-neu, or p53 genes, ruling out their involvement in tumor development.
Area of Science:
- Oncology
- Molecular Biology
- Carcinogenesis
Background:
- N-ethyl-N-nitrosourea (ENU) is a chemical carcinogen that induces genetic point mutations.
- The oncogene abnormalities in rat mammary tumors induced by ENU are not well-characterized.
- Metastatic clones Br7-C5 and FP2-All were derived from the ENU1564 rat adenocarcinoma cell line.
Purpose of the Study:
- To evaluate the ENU1564 rat mammary tumor line for mutational activation of key oncogenes.
- To investigate the roles of c-Ha-ras, c-neu, and p53 in ENU-induced mammary tumors.
- To characterize oncogene abnormalities in highly metastatic rat mammary adenocarcinoma.
Main Methods:
- Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze c-Ha-ras and c-neu genes.
- Sequence-specific oligonucleotide hybridization and single-stranded conformational polymorphism (PCR-SSCP) were employed for mutation detection.
- Immunoprecipitation and Western immunoblotting were performed to assess p53 protein expression and integrity.
Main Results:
- No mutations were detected in c-Ha-ras codon 12.
- No sequence changes were found in the c-neu protooncogene spanning codon 664.
- The p53 protein was neither over-expressed nor mutated in the analyzed tumor cells.
Conclusions:
- The study failed to identify specific oncogene alterations in the ENU1564 rat mammary tumor line.
- Mutational activation of c-Ha-ras (codon 12), c-neu (codon 664), and p53 genes was ruled out as a cause for these tumors.
- Further research is needed to elucidate the genetic basis of ENU-induced rat mammary tumors.
