Effect of captopril on Ca 2+ homeostasis and cell viability in human hepatoma cells

I. Shu Chen, Chiang Ting Chou, Wei Zhe Liang, Yuan Yuarn Liu, Chun Chi Kuo, Jue Long Wang, Lyh Jyh Hao, Chung Ren Jan*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

3 Scopus citations

Abstract

Captopril, an angiotensin-converting enzyme (ACE) inhibitor, induced different Ca 2+ signaling responses in various cell models. However, the effect of captopril on Ca 2+ homeostasis and cell viability in hepatoma cells is unknown. This study examined whether captopril altered Ca 2+ homeostasis and viability in HepG2 human hepatoma cells. Intracellular Ca 2+ concentrations in suspended cells were monitored by using the fluorescent Ca 2+ -sensitive dye fura-2. Cell viability was examined by using 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1). Captopril at concentrations of 500-3000 µM induced cytosolic free concentrations of Ca 2+ ([Ca 2+ ] i ) rises in a concentration-dependent manner. Ca 2+ removal reduced the signal by approximately 15%. Mn 2+ has been shown to enter cells through similar mechanisms as Ca 2+ but quenches fura-2 fluorescence at all excitation wavelengths. Captopril (3000 μM)-induced Mn 2+ influx indirectly suggested that captopril evoked Ca 2+ entry. Captopril-induced Ca 2+ entry was inhibited by 15% by a protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA) and an inhibitor (GF109203X) and three inhibitors of store-operated Ca 2+ channels: nifedipine, econazole and SKF96365. In Ca 2+ -free medium, treatment with the endoplasmic reticulum Ca 2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished captopril-evoked [Ca 2+ ] i rises. Conversely, treatment with captopril abolished BHQ-evoked [Ca 2+ ] i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited 70% of captopril-induced [Ca 2+ ] i rises. Captopril at concentrations between 150- 550 μM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca 2+ with 1,2-bis(2- aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid/acetoxy methyl (BAPTA/AM) did not reverse captopril’s cytotoxicity. Together, in HepG2 human hepatoma cells, captopril induced [Ca 2+ ] i rises and caused cell death that was not triggered by preceding [Ca 2+ ] i rises.

Original languageEnglish
Pages (from-to)221-229
Number of pages9
JournalChinese Journal of Physiology
Volume61
Issue number4
DOIs
StatePublished - 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 by The Chinese Physiological Society.

Keywords

  • Ca
  • Captopril
  • Endoplasmic reticulum
  • Human hepatoma cells
  • Viability

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