UC Riverside

Molecular Oxygen is one of the most important molecules in living organisms. Oxygen is the final electron acceptor in the Electron Transport Chain (ETC), which allows organisms to produce ATP. In mammals, oxygen and its chemically similar relatives, reactive oxygen species (ROS) can be used in signaling. For example, one ROS species, H2O2, can signal for apoptosis at low levels. In cancer, increasing the chance that a cell will undergo apoptosis can be useful. New drug targets are necessary for Castration Resistant Prostate Cancer (CRPC). Catalase, an enzyme that detoxifies the cell from H2O2, was shown to be a viable drug target for CRPC by demonstrating tumor reduction in mice. Catalase deficient cells also migrated slower, proliferated slower, and had altered adhesion. On the other hand, too much ROS in mammals can lead to DNA damage, as well as the oxidation of lipids and proteins. An accumulation of damaged DNA, lipids and proteins can lead to long term health impacts. ROS can be produced endogenously or can come from environmental sources like tobacco smoke. A historically underappreciated source of ROS is Third hand Smoke (THS). THS refers to the class of chemicals that reside in or on surfaces after secondhand tobacco smoke has settled and cleared. In this study, THS exposure was shown to increase the relative methylation in mitochondrial DNA. (mtDNA). This could possibly explain the metabolic phenotypes that has been observed in THS exposed mice in previous studies.