NPC-14686, a novel anti-inflammatory agent, increased intracellular Ca(2+) concentrations in MDCK renal tubular cells

• Published in: International journal of immunopharmacology 2000-11, Vol.22 (11), p.915-921
• Main Authors: Jan, C R, Wang, J L, Chou, K J, Cheng, J S, Lee, K C, Tseng, L L, Wang, S P, Tang, K Y, Huang, J K
• Format: Article
• Language: English
• Subjects: Aminobutyrates - pharmacology; Animals; Anti-Inflammatory Agents - pharmacology; Calcium - metabolism; Carbonyl Cyanide m-Chlorophenyl Hydrazone - pharmacology; Cell Survival - drug effects; Cells, Cultured; Dogs; Inositol 1,4,5-Trisphosphate - physiology; Kidney Tubules - cytology; Kidney Tubules - drug effects; Kidney Tubules - metabolism
• ISSN: 0192-0561
• DOI: 10.1016/S0192-0561(00)00054-0

The effect of NPC-14686 (Fmoc-L-homophenylalanine), a novel anti-inflammatory agent on intracellular free Ca(2+) concentrations ([Ca(2+)](i)) in Madin Darby canine kidney (MDCK) renal tubular cells, was investigated, using fura-2 as a Ca(2+) dye. At concentrations between 10 and 200 microM NPC-14686 increased [Ca(2+)](i) concentration dependently. The [Ca(2+)](i) signal comprised an initial rise and a sustained phase. Ca(2+) removal inhibited the Ca(2+) signals by 90%. In Ca(2+)-free medium, pretreatment with 100 microM NPC-14686 nearly abolished the [Ca(2+)](i) increase induced by 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) and abolished the [Ca(2+)](i) increase induced by 2 microM carbonylcyanide m-chlorophenylhydrazone (CCCP) (a mitochondrial uncoupler). NPC-14686 (100 microM) induced a slight [Ca(2+)](i) increase after pretreatment with 2 microM CCCP and 1 microM thapsigargin. Addition of 3 mM Ca(2+) elicited a [Ca(2+)](i) increase in cells pretreated with 100 microM NPC-14686 in Ca(2+)-free medium. Inhibition of inositol-1,4,5-trisphosphate (IP(3)) production by suppressing phospholipase C with 2 microM U73122 did not alter NPC-14686-induced Ca(2+) release. Trypan blue exclusion revealed that incubation with 10 or 200 microM NPC-14686 for 1-30 min decreased cell viability by 10-20% concentration dependently. Collectively, the results demonstrate that, in MDCK tubular cells, NPC-14686 induced Ca(2+) release followed by Ca(2+) entry, with the latter playing a major role. NPC-14686 appears to release intracellular Ca(2+) in an IP(3)-uncoupled manner. NPC-14686 may be of mild cytotoxicity.