Role of intracellular calcium mobilization and cell-density-dependent signaling in oxidative-stress-induced cytotoxicity in HaCaT keratinocytes

Edina Bakondi, Mónika Gönczi, Éva Szabó, Péter Bai, Pál Pacher, Pál Gergely, László Kovács, János Hunyadi, Csaba Szabó, László Csernoch, László Virág

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Peroxynitrite is a nitric-oxide-derived cytotoxic mediator produced in a broad range of inflammatory conditions, ranging from sunburn erythema to contact hypersensitivity. Our previous work has shown that in HaCaT cells the cytotoxic activity of peroxynitrite involves both apoptotic and necrotic routes with poly (ADP-ribose) polymerase activation serving as a molecular switch diverting the default apoptotic pathway toward necrosis. Nonetheless, keratinocytes are regarded as highly resistant toward environmental noxa including oxidative stress. We set out to investigate the possible role of two parameters, intracellular calcium mobilization and high cell density, in protecting HaCaT cells from peroxynitrite/oxidative-stress-induced cytotoxicity. First we characterized the effect of peroxynitrite on the calcium homeostasis of HaCaT cells and demonstrated that both authentic peroxynitrite and the peroxynitrite generating compound 3-morpholino-sydnonimine triggered an elevation in intracellular calcium levels. Moreover, we established that treatment of cells with the cell-permeable calcium chelator BAPTA-AM provided significant cytoprotection against peroxynitrite- and hydrogen-peroxide-induced cytotoxicity. Furthermore, when cells reached confluence they were highly resistant to the toxic effects of peroxynitrite, hydrogen peroxide, and superoxide. The resistance to oxidative stress provided by calcium chelation and high cell density involved inhibiting the activation of both poly(ADP-ribose) polymerase and caspases. Our data may provide an explanation for the resistance to oxidative stress of superficial, highly differentiated keratinocytes and indicate that basal proliferative keratinocytes are sensitive in vivo targets of oxidative stress injury.

Original languageEnglish (US)
Pages (from-to)88-95
Number of pages8
JournalJournal of Investigative Dermatology
Issue number1
StatePublished - Jul 1 2003
Externally publishedYes


  • Apoptosis
  • Calcium signaling
  • Hydrogen peroxide
  • Necrosis
  • Peroxynitrous acid

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Dermatology
  • Cell Biology


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