Biomarker for Benzopyrene Exposure Is Mitochondrial Mass and Mitochondrial DNA Copy in Blood Cells and Hematopoietic Tissues

Abstract 4889

Benzopyrenes are well known pollutants and carcinogens. They can intercalate into DNA and interfere transcriptions, resulting in causing various human diseases. However, biomarkers of benzopyrene toxicity have not been comprehensively studied in blood and leukemia cells. The current study was investigated to discover biomarkers for benzopyrene exposure in blood cells and leukemia cell lines. Peripheral blood, peripheral blood hematopoietic stem cell and leukemia cells (THP-1, K562, Molt-4 and HL-60) were cultured in RPMI 1640 media with adding 0, 50, 100 and 200μM of benzopyrene. Viability and apoptosis were assessed by tryptophan blue dye exclusion test and flowcytometry using annexin V. Hydrogen peroxide was measured using enzyme immunoassay. Mitochondrial mass, membrane potential and mitochondrial DNA (mtDNA) copy number were measured using MitoTracker Green, Red probes and real time PCR, respectively. The number of cell remained constant for three weeks culture. Viability of four cell lines disclosed significant decrease after two weeks of benzopyrene treatment. Apoptosis was increased in time- and dose-dependent manner after two weeks of benzopyrene treatment. Mitochondrial contents and membrane potentials were dramatically increased in three-week culture at dose dependent manner. Hydrogen peroxide level was significantly elevated after two weeks treatment of benzopyrene compared to non-benzopyrene treatment group. The number of mtDNA copy increased gradually after exposure to benzopyrene. These results indicated that increased mitochondrial mass and mtDNA copy number were biomarkers for direct exposure of benzopyrene in blood cells and hematopoietic tissues.