SBIR-STTR Award

The purpose of this project is to demonstrate the feasibility to detect organ-specific mutagenic responses to a variety of chemical compounds in relation to organ-specific carcinogenic action. A transgenic mouse model was constructed carrying multiple copies of a plasmid, containing the bacterial lacZ marker gene, integrated head-to-tail in the genome of all organs and tissues. Highly efficient protocols for the rescue of these vectors from their integrated state have been developed. The detection of mutations in the lacZ reporter gene is facilitated by a positive selection system. The use of this novel lacZ plasmid--based transgenic mouse model makes it now possible to study DNA damage and mutant induction in the same animal and in the same organ after treatment with low doses of a particular carcinogenic agent. This new in vivo transgenic mouse mutagenicity assay provides an unique opportunity to study the induction of tissue-specific mutations that reflect the integration of pharmacokinetics, biotransformation, DNA repair responses, and tissue susceptibility. PROPOSED COMMERCIAL APPLICATION: The development of new drugs and chemicals by pharmaceutical and chemical industries requires that the safety of these new compounds is evaluated as regards to their potential Toxic effects. The transgenic mouse mutation assay, as described in this project, is expected to become a standard tool in toxicology testing by industry, third-party agencies and medical schools and universities involved in toxicological testing and cancer risk assessment. As such, this new assay has great commercial potential

The acceptance of alternative toxicological test methods by regulatory agencies is determined by their reliability and relevance for a given purpose, i.e. whether the test method has been validated. If a test for genotoxicity can be selected according to toxicological principles so that, in concert, they detect the full range of mutagenic events that could ultimately lead to cancer, then theoretically the test optimal predictive of carcinogenicity will have been selected. The purpose of this Phase II project is to validate the new lacZ plasmid-based transgenic mouse mutation assay. These transgenic mice carry multiple copies of a plasmid, containing the bacterial lacZ marker gene, integrated head-to-tail in the genome of all organs and tissues. Highly efficient protocols for the rescue of these vectors from their integrated state have been developed. The detection of mutations in the lacZ reporter gene is facilitated by a positive selection system. Our approach would be to correlate mutagenicity with tumor formation in a selected number of target and non-target tissues following exposure to these chemicals. This should help to define the measure of relevance of the plasmid-based transgenic mouse mutation assay such as operational characteristics (sensitivity, specificity), statistically derived correlation coefficients, and determinations of the mechanistic association of the measured effect (mutant frequency) with the toxic event of interest (carcinogenicity).PROPOSED COMMERCIAL APPLICATION: Validation of this new lacZ-plasmid-based transgenic mouse model will help to position this model as a definitive model for toxicological testing of new pharmaceuticals, chemicals etc. When accepted as such by governmental regulatory agencies, it will greatly increase the sales of kits Leven is currently selling for this system.

Thesaurus Terms:
biological model, carcinogen testing, chemical carcinogen, gene mutation, laboratory mouse, method development, model design /development, mutagen testing, transgenic animal DNA damage, chemical, chemical carcinogenesis, gene expression, gene targeting, neoplasm /cancer genetics, organ, plasmid, toxicant screening histopathologyNATIONAL CANCER INSTITUTE