Thiol oxidation by 2,2'-dithiodipyridine induced calcium mobilization in MG63 human osteosarcoma cells.

Abstract

2,2'-dithiodipyridine (2,2'-DTDP), a reactive disulphide that mobilizes Ca(2+) in muscle, induced an increase in cytoplasmic free Ca(2+)concentrations ([Ca(2+)](i)) in MG63 human osteosarcoma cells loaded with the Ca(2+)-sensitive dye fura-2. 2,2'-DTDP acted in a concentration-independent manner with an EC(50) of 50 microM. The Ca(2+) signal comprised an initial spike and a prolonged increase. Removing extracellular Ca(2+) did not alter the Ca(2+) signal, suggesting that the Ca(2+) signal was due to store Ca(2+) release. In Ca(2+)-free medium, the 2,2'-DTDP-induced [Ca(2+)](i) increase was not changed by depleting store Ca(2+) with 50 microM bredfeldin A (a Golgi apparatus permeabilizer), 2 microM carbonylcyanide m-chlorophenylhydrazone (CCCP, a mitochondrial uncoupler), 1 microM thapsigargin (an endoplasmic reticulum Ca(2+)pump inhibitor) or 5 microM ryanodine. Conversely, 2,2'-DTDP pretreatment abolished CCCP and thapsigargin-induced [Ca(2+)](i) increases. 2,2'-DTDP-induced Ca(2+) signals in Ca(2+)-containing medium were not affected by modulation of protein kinase C activity or suppression of phospholipase C activity. However, 2,2'-DTDP-induced Ca(2+) release was inhibited by a thiol-selective reducing reagent, dithiothreitol (5-25 microM) in a concentration-dependent manner. Collectively, this study shows that 2,2'-DTDP induced [Ca(2+)](i) increases in human osteosarcoma cells via releasing store Ca(2+)from multiple stores in a manner independent of protein kinase C or phospholipase C activity. The 2,2'-DTDP-induced store Ca(2+) release appeared to be dependent on oxidation of membranes.

• Authors: Soong-Yu Kuo, Bang-Ping Jiann, Yih-Chau Lu, Hong-Tai Chang, Wei-Chung Chen, Jong-Khing Huang, Chung-Ren Jan
• Journal: Life sciences (Life Sci) Vol. 72 Issue 15 Pg. 1733-43 (Feb 28 2003) ISSN: 0024-3205 [Print] Netherlands
• PMID: 12559394 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2002 Elsevier Science Inc.

Chemical References

• Disulfides
• Enzyme Inhibitors
• Fluorescent Dyes
• Protein Synthesis Inhibitors
• Reducing Agents
• Sulfhydryl Compounds
• Brefeldin A
• 2,2'-dipyridyl disulfide
• 2,2'-Dipyridyl
• Thapsigargin
• Protein Kinase C
• Type C Phospholipases
• Calcium
• Fura-2

Topics

• 2,2'-Dipyridyl (analogs & derivatives, pharmacology)
• Bone Neoplasms (metabolism)
• Brefeldin A (pharmacology)
• Calcium (metabolism)
• Calcium Signaling (drug effects)
• Disulfides (pharmacology)
• Enzyme Inhibitors (pharmacology)
• Fluorescent Dyes
• Fura-2
• Humans
• Osteosarcoma (metabolism)
• Oxidation-Reduction
• Protein Kinase C (antagonists & inhibitors, metabolism)
• Protein Synthesis Inhibitors (pharmacology)
• Reducing Agents (pharmacology)
• Second Messenger Systems (drug effects)
• Sulfhydryl Compounds (metabolism)
• Thapsigargin (pharmacology)
• Tumor Cells, Cultured
• Type C Phospholipases (metabolism)