Involvement of calcium-mediated apoptotic signals in H2O2-induced MIN6N8a cell death

Eur J Pharmacol. 2006 Oct 10;547(1-3):1-9. doi: 10.1016/j.ejphar.2006.06.016. Epub 2006 Jun 15.


Reactive oxygen species are believed to be the central mediators of beta-cell destruction that leads to type 1 and 2 diabetes, and calcium has been reported to be an important mediator of beta cell death. In the present study, the authors investigated whether Ca(2+) plays a role in hydrogen peroxide (H(2)O(2))-induced MIN6N8a mouse beta cell death. Treatment with low concentration H(2)O(2) (50 microM) was found to be sufficient to reduce MIN6N8a cell viability by 55%, largely via apoptosis. However, this H(2)O(2)-induced cell death was near completely blocked by pretreatment with BAPTA/AM (5 microM), a chelator of intracellular Ca(2+). Moreover, the intracellular calcium store channel blockers, such as, xestospongin c and ryanodine, significant protected cells from 50 microM H(2)O(2)-induced cell death and under extracellular Ca(2+)-free conditions, 50 microM H(2)O(2) elicited transient [Ca(2+)](i) increases. In addition, pharmacologic inhibitors of calpain, calcineurin, and calcium/calmodulin-dependent protein kinase II were found to have a protective effect on H(2)O(2)-induced death. Moreover, H(2)O(2)-induced apoptotic signals, such as c-JUN N-terminal kinase activation, cytochrome c release, caspase 3 activation, and poly (ADP-ribose) polymerase cleavage were all down-regulated by the intracellular Ca(2+) chelation. These findings show that [Ca(2+)](i) elevation, possibly due to release from intracellular calcium stores and the subsequent activation of Ca(2+)-mediated apoptotic signals, critically mediates low concentration H(2)O(2)-induced MIN6N8a cell death. These findings suggest that a breakdown of calcium homeostasis by low level of reactive oxygen species may be involved in beta cell destruction during diabetes development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Calcineurin / metabolism
  • Calcineurin Inhibitors
  • Calcium / antagonists & inhibitors
  • Calcium / metabolism*
  • Calpain / antagonists & inhibitors
  • Calpain / metabolism
  • Caspase 3 / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Chelating Agents / pharmacology
  • Dose-Response Relationship, Drug
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Hydrogen Peroxide / toxicity*
  • Insulinoma / metabolism
  • Insulinoma / pathology
  • Intracellular Fluid / drug effects
  • Intracellular Fluid / metabolism
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Macrocyclic Compounds / pharmacology
  • Oxazoles / pharmacology
  • Oxidants / toxicity
  • Poly(ADP-ribose) Polymerases / metabolism
  • Ryanodine / pharmacology
  • Signal Transduction / drug effects*


  • Calcineurin Inhibitors
  • Chelating Agents
  • Enzyme Inhibitors
  • Macrocyclic Compounds
  • Oxazoles
  • Oxidants
  • xestospongin C
  • 1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
  • Ryanodine
  • Egtazic Acid
  • Hydrogen Peroxide
  • Poly(ADP-ribose) Polymerases
  • JNK Mitogen-Activated Protein Kinases
  • Calcineurin
  • Calpain
  • Caspase 3
  • Calcium