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Effect of MK‐886 on Ca 2+ Level and Viability in PC3 Human Prostate Cancer Cells
Author(s) -
Huang JongKhing,
Huang ChorngChih,
Lu Ti,
Chang HongTai,
Lin KoLong,
Tsai JengYu,
Liao WeiChuan,
Chien JauMin,
Jan ChungRen
Publication year - 2009
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/j.1742-7843.2009.00413.x
Subject(s) - thapsigargin , fura 2 , bapta , extracellular , chemistry , endoplasmic reticulum , phospholipase c , cytosol , viability assay , endocrinology , biophysics , medicine , microbiology and biotechnology , in vitro , biochemistry , biology , signal transduction , enzyme
3‐[1‐( p ‐chlorobenzyl)‐5‐(isopropyl)‐3‐ tert ‐butylthioindol‐2‐yl]‐2, 2‐dimethylpropanoic acid (MK‐886) is widely used for inhibition of leucotriene synthesis in in vitro studies, however, many of its other effects have been reported. The present study investigated the effect of MK‐886 on cytosolic‐free Ca 2+ concentrations ([Ca 2+ ] i ) and viability in human PC3 prostate cancer cells. [Ca 2+ ] i in suspended cells was measured by using fura‐2. MK‐886 at concentrations of 1 µM and above increased [Ca 2+ ] i in a concentration‐dependent manner with an EC 50 value of 20 µM. The Ca 2+ signal was reduced partly by removing extracellular Ca 2+ . MK‐886 evoked Mn 2+ quenching of fura‐2 fluorescence, implicating Ca 2+ entry. MK‐886‐induced Ca 2+ influx was inhibited by store‐operated Ca 2+ entry inhibitors nifedipine, econazole and SKF96365. In Ca 2+ ‐free medium, after pre‐treatment with 10 µM MK‐886, 1 µM thapsigargin (an endoplasmic reticulum Ca 2+ pump inhibitor)‐induced [Ca 2+ ] i rises were abolished; and conversely, thapsigargin pre‐treatment abolished MK‐886‐induced [Ca 2+ ] i rises. Inhibition of phospholipase C with U73122 did not alter MK‐886‐induced [Ca 2+ ] i rises. MK‐886 at concentrations of 1–100 µM concentration‐dependently decreased cell viability with an IC 50 value of 60 µM. The cytotoxic effect of MK‐886 was not inhibited by pre‐chelating cytosolic Ca 2+ with BAPTA/AM. Together, in PC3 cells, MK‐886 induced [Ca 2+ ] i rises by causing phospholipase C‐independent Ca 2+ release from the endoplasmic reticulum; and Ca 2+ influx via store‐operated Ca 2+ channels. Independently, MK‐886 was cytotoxic to cells in a Ca 2+ ‐independent manner.