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Intracellular calcium concentrations in human bladder tumor cells could be increased by NPC‐14686, a novel antiinflammatory agent
Author(s) -
Huang JongKhing,
Jan ChungRen
Publication year - 2000
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/1098-2299(200006)50:2<147::aid-ddr3>3.0.co;2-q
Subject(s) - thapsigargin , endoplasmic reticulum , intracellular , inositol , fura 2 , chemistry , phospholipase c , calcium , inositol trisphosphate , endocrinology , protein kinase c , medicine , biophysics , microbiology and biotechnology , biochemistry , biology , kinase , cytosol , receptor , enzyme , organic chemistry
NPC‐14686 (Fmoc‐L‐homophenylalanine), a novel antiinflammatory agent, increases intracellular Ca 2+ concentrations ([Ca 2+ ] i ] in T24 bladder tumor cells. Using fura‐2 as a Ca 2+ probe, NPC‐14686 (10–200 μM) increased [Ca 2+ ] i in a concentration‐dependent manner. The [Ca 2+ ] i increase comprised an initial slow rise and a plateau over a time period of 5 min. Ca 2+ removal partly inhibited the Ca 2+ signals. In Ca 2+ ‐free medium, pretreatment with 100 μM NPC‐14686 abolished the [Ca 2+ ] i increases induced by 1 μM thapsigargin (an endoplasmic reticulum Ca 2+ pump inhibitor] and 2 μM carbonylcyanide m‐chlorophenylhydrazone (a mitochondrial uncoupler). However, 100 μM NPC‐14686 still slightly increased [Ca 2+ ] i after Ca 2+ stores had been depleted by pretreating with 2 μM CCCP and 1 μM thapsigargin. These results suggest that NPC‐14686 released Ca 2+ from multiple pools. Adding 3 mM Ca 2+ increased [Ca 2+ ] i in cells pretreated with 100 μM NPC‐14686 in Ca 2+ ‐free medium, indicating that NPC‐14686 activated capacitative Ca 2+ entry. Inhibiting formation of inositol‐1,4,5‐trisphosphate (IP 3 ] by blocking phospholipase C with 2 μM U73122 had little effect on NPC‐14686‐induced Ca 2+ release. Activating protein kinase C with phorbol 12‐myristate 13‐acetate (PMA) significantly potentiated NPC‐14686‐induced [Ca 2+ ] i increase. NPC‐14686 (100 μM) also increased [Ca 2+ ] i in MDCK renal cells, BFTC bladder tumor cells, and MS‐1 endothelial cells. Together, the findings suggest that in T24 bladder tumor cells NPC‐14686 induced Ca 2+ release followed by Ca 2+ entry. The Ca 2+ release was unlinked to IP 3 and the [Ca 2+ ] i signal could be modulated by protein kinase C. Drug Dev. Res. 50:147–152, 2000. © 2000 Wiley‐Liss, Inc.