IP 3 receptor antagonist, 2-APB, attenuates cisplatin induced Ca 2+-influx in HeLa-S3 cells and prevents activation of calpain and induction of apoptosis

F. Splettstoesser, A. M. Florea, Dietrich Busselberg

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Abstract

Background and purpose: Cisplatin drives specific types of tumour cells to apoptosis. In this study we investigate the involvement of intracellular calcium ([Ca 2+] i) in triggering apoptosis in two different cell lines. As cisplatin is used for the treatment of several forms of cancer we choose HeLa-S3 and U2-OS as two examples of tumour cell lines. Experimental approach: Cisplatin (1nM-10μM) was applied to HeLa-S3 and U2-OS cells and [Ca 2+] i measured with fluo-4, using laser scanning microscopy. Inositol-1,4,5-trisphosphate (IP 3) receptors were visualized with immunostaining. Membrane conductances were measured with patch-clamp techniques. Levels of calpain and caspases were assessed by western blots and apoptotic cells were stained with Hoechst 33342 and counted. Key results: Cisplatin increases [Ca 2+] i concentration- dependently in HeLa-S3 but not in U2-OS cells. This elevation of [Ca 2+] i depended on extracellular Ca 2+ but was reduced by the IP 3 receptor blocker, 2-APB. This effect was not due to a Ca 2+ release triggered by Ca 2+ entry. Immunostaining showed IP 3-receptors (type1-3) at the cellular membrane of HeLa-S3 cells, but not in U2-OS cells. Electrophysiological experiments showed an increased membrane conductance with cisplatin only when Ca 2+ was present extracellularly. Increase of [Ca 2+] i was related to the activation of calpain but not caspase-8 and triggered apoptosis in HeLa-S3 but not in U2-OS cells. Conclusions and implications: Our observations on the activation of IP 3-receptors, calcium entry and apoptotic rate by cisplatin in specific carcinogenic cells might open new possibilities in the treatment of some forms of cancer.

Original languageEnglish
Pages (from-to)1176-1186
Number of pages11
JournalBritish Journal of Pharmacology
Volume151
Issue number8
DOIs
Publication statusPublished - Aug 2007
Externally publishedYes

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Keywords

  • [Ca ]
  • Anticancer drugs
  • Apoptosis
  • Calcium signalling
  • Calcium stores
  • Calpain
  • Carboplatin
  • Cisplatin
  • HeLa-S3
  • IP -receptor
  • U2-OS

ASJC Scopus subject areas

  • Pharmacology

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