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Detection of novel non-ras oncogenes in rat nasal squamous cell carcinomas
A E Hochwalt1, I Wirgin, M Felber
1Department of Environmental Medicine, New York University Medical Center, New York 10016.
Abstract:
Rat nasal squamous cell carcinomas induced by inhalation of three direct-acting alkylating agents yielded DNA containing activated oncogenes with no homology to any member of the ras family. The novel NIH 3T3 transforming oncogenes from tumors induced by beta-propiolactone and methylmethane sulfonate are distinct from each other based on restriction analysis. The gene isolated from beta-propiolactone-induced tumors is between 6 and 9 kb in size. None of the tumors induced by dimethylcarbamyl chloride contained positive DNA in the NIH 3T3 focus assay or in the nude mouse cotransfection assay. The rat nasal tumor model is apparently ideally suited for analysis of the roles of carcinogen and tissue specificity in oncogene activation, especially related to novel (non-ras) transforming oncogenes.
Insights
Researchers identified novel oncogenes in rat nasal tumors caused by alkylating agents. These newly discovered genes, distinct from the ras family, offer insights into carcinogen-specific tumor development.
Area of Science:
- Oncology
- Molecular Biology
- Toxicology
Background:
- Squamous cell carcinomas in rat nasal tissues were induced using direct-acting alkylating agents.
- DNA analysis revealed activated oncogenes in these tumors, unrelated to the known ras family.
- The study focused on understanding oncogene activation mechanisms in chemically induced cancers.
Purpose of the Study:
- To identify and characterize novel transforming oncogenes activated by specific carcinogens.
- To investigate the role of carcinogen and tissue specificity in oncogene activation.
- To explore non-ras oncogenes in the context of chemically induced rat nasal tumors.
Main Methods:
- Induction of rat nasal tumors using beta-propiolactone, methylmethane sulfonate, and dimethylcarbamyl chloride.
- NIH 3T3 focus assay and nude mouse cotransfection assay for detecting transforming activity.
- Restriction analysis to differentiate between isolated oncogenes.
Main Results:
- Novel NIH 3T3 transforming oncogenes were identified in tumors induced by beta-propiolactone and methylmethane sulfonate.
- These oncogenes showed distinct profiles via restriction analysis, indicating they are different genes.
- Tumors induced by dimethylcarbamyl chloride did not yield positive results in the assays used.
- The gene from beta-propiolactone-induced tumors measured between 6 and 9 kb.
Conclusions:
- The rat nasal tumor model is effective for studying carcinogen-specific oncogene activation.
- Novel, non-ras transforming oncogenes play a role in chemically induced nasal tumors.
- Further research can elucidate the specific roles of these novel oncogenes in carcinogenesis.