International Programs

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic chemical compounds found in the environment, largely as a result of partial combustion of organic compounds. PAHs are present in the atmosphere in populated cities worldwide. Because of the health risks they create, PAHs are a global health concern. PAHs are introduced into the body, primarily through diet. Cells metabolize PAHs into highly reactive diol epoxides, which react with DNA, forming PAH-DNA adducts. These adducts can cause mutations in DNA, contributing to the increased risk of cancer associated with PAH exposure. DNA mismatch repair (MMR) is a cellular mechanism that protects the genomic integrity of a cell. Mismatch repair deficiencies are associated with human cancer, particularly colorectal cancer. It is hypothesized that MMR status will influence cellular responses to PAH exposure; specifically, MMR-deficient cells will show decreased apoptosis and increased mutations induced by exposure to PAHs. The goal of this project is to determine how to use a cell culture model to measure mutations induced by PAH exposure in MMR proficient and deficient human cells. We conclude that Alamar Blue is an appropriate, efficient reagent and method for cell density and viability measurements in 96-well plate cultures and we demonstrate the conditions for the phenotypic selection of HPRT mutants with 6-thioguanine.