Shikha Agnihotry
Sam Higginbottom University of Agriculture, Technology and Sciences, India
Title: Roles of ATP7B gene to maintain the copper-transporting ATPase in a HepG2 cell line against excess copper toxicity
Biography
Biography: Shikha Agnihotry
Abstract
Wilson disease (WD) is an autosomal recessive disorder of copper transport with a worldwide frequency of ~1 in 30000. Wilson’s disease is characterized by chronic liver and neurological disease and also reported in kidney. Hepatic copper levels vary among normal individuals and WD patients depending upon on dietary copper intake and bioavailability, as well as genetic factors. In this study we examined that abnormal copper accumulation in human heptocarcinoma (HepG2) cell line. Copper chloride (CuCl2) caused dose dependent cell viability reduction of human hepatocarcinoma (HepG2) cell line which was measured through MTT assay. We used different concentration of CuCl2 in their log doses but maximum cell viability reduction was recorded at 15 µg/ml. It also induces cell cycle arrest and DNA damage due to intracellular ROS generation. CuCl2 induces Ca2+ release from endoplasmic reticulum (ER) and leads to apoptotic cell death. It causes the up-regulation of WD stress marker genes ATP7B and Cyp1A1, Cyp1A2 at transcription levels. The similar response of ATP7B and Cyp1A1, Cyp1A2 proteins was recorded at translation levels. Heavy dietary intake of CuCl2 induces mitochondria and reduced the mitochondrial membrane potential analyzed through JC-1 staining. It further increases Bax/Bcl2 ratio and promotes the release of cytochrome C, finally leads to caspase-dependent apoptosis. Up-regulation of APAF1 in CuCl2 treated cells supports the mitochondrial-mediated apoptotic cell death. The results support the involvement of ER and mitochondria in ROS mediated CuCl2 toxicity. Therefore, the heavy dietary intake of CuCl2 in food products may be deleterious to users.