Effect of bisphenol A on Ca(2+) fluxes and viability in Madin-Darby canine renal tubular cells

• Published in: Drug and chemical toxicology (New York, N.Y. 1978) N.Y. 1978), 2011-10, Vol.34 (4), p.454-461
• Main Authors: Kuo, Chun-Chi, Huang, Jong-Khing, Chou, Chiang-Ting, Cheng, Jin-Shiung, Tsai, Jeng-Yu, Fang, Yi-Chien, Hsu, Shu-Shong, Liao, Wei-Chuan, Chang, Hong-Tai, Ho, Chin-Man, Jan, Chung-Ren
• Format: Article
• Language: English
• Subjects: Animals; Benzhydryl Compounds; Calcium - metabolism; Calcium Signaling - drug effects; Cell Culture Techniques; Cell Line; Cell Survival - drug effects; Data Interpretation, Statistical; Diploidy; Dogs; Dose-Response Relationship, Drug; Endocrine Disruptors - toxicity; Flow Cytometry; Kidney Tubules - cytology; Kidney Tubules - drug effects; Kidney Tubules - enzymology; Kidney Tubules - metabolism; Phenols - toxicity; Phospholipase A2 Inhibitors; Type C Phospholipases - antagonists & inhibitors
• ISSN: 1525-6014
• DOI: 10.3109/01480545.2011.556645

The effect of the environmental contaminant, bisphenol A, on cytosolic free Ca(2+) concentrations ([Ca(2+)](i)) in Madin-Darby canine kidney (MDCK) cells is unclear. This study explored whether bisphenol A changed basal [Ca(2+)](i) levels in suspended MDCK cells by using fura-2 as a Ca(2+)-sensitive fluorescent dye. Bisphenol A, at concentrations between 50 and 300 µM, increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was reduced, partly, by removing extracellular Ca(2+). Bisphenol A induced Mn(2+) influx, leading to quenching of fura-2 fluorescence, suggesting Ca(2+) influx. This Ca(2+) influx was inhibited by phospholipase A2 inhibitor aristolochic acid, store-operated Ca(2+) channel blockers nifedipine and SK&F96365, and protein kinase C inhibitor GF109203X. In Ca(2+)-free medium, pretreatment with the mitochondrial uncoupler, carbonylcyanide m-chlorophenylhydrazone (CCCP), and the endoplasmic reticulum Ca(2+) pump inhibitors, thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ), inhibited bisphenol A-induced Ca(2+) release. Conversely, pretreatment with bisphenol A abolished thapsigargin (or BHQ)- and CCCP-induced [Ca(2+)](i) rise. Inhibition of phospholipase C with U73122 abolished bisphenol-induced [Ca(2+)](i) rise. Bisphenol A caused a concentration-dependent decrease in cell viability via apoptosis in a Ca(2+)-independent manner. Collectively, in MDCK cells, bisphenol A induced [Ca(2+)](i) rises by causing phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and mitochondria and Ca(2+) influx via phospholipase A2-, protein kinase C-sensitive, store-operated Ca(2+) channels.