Soong-Yu Kuo

[6]-gingerol induces Ca2+ mobilization in Madin-Darby canine kidney cells.

[6]-gingerol, a major phenolic compound derived from ginger (Zingiber officinale), is a potential chemopreventive compound that can induce stress in cancer cells and cause apoptotic cell death. This study examines the early signaling effects of [6]-gingerol on renal cells. It was found that [6]-gingerol caused a slow and sustained rise of [Ca2+]i in a concentration-dependent manner. [6]-gingerol also induced a [Ca2+]i rise when extracellular Ca2+ was removed, but the magnitude was reduced by 80%. Depletion of intracellular Ca2+ stores with CCCP, a mitochondrial uncoupler, did not affect the action of [6]-gingerol. In a Ca2+-free medium, the [6]-gingerol-induced [Ca2+]i rise was partially abolished by depleting stored Ca2+ with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). The elevation of [6]-gingerol-caused [Ca2+]i in a Ca2+-containing medium was not affected by modulation of protein kinase C activity. The [6]-gingerol-induced Ca2+ influx was blocked by nicardipine. U73122, an inhibitor of phospholipase C, abolished ATP (but not [6]-gingerol)-induced [Ca2+]i rise. These findings suggest that [6]-gingerol induces a significant rise in [Ca2+]i in MDCK renal tubular cells by stimulating both extracellular Ca2+ influx and thapsigargin-sensitive intracellular Ca2+ release via as yet unidentified mechanisms.

Effect of Allyl Sulfides from Garlic Essential Oil on Intracellular Ca2+ Levels in Renal Tubular Cells

Diallyl sulfide (1), diallyl disulfide (2), and diallyl trisulfide (3), which are major organosulfur compounds of garlic (Allium sativum), are recognized as a group of potential chemopreventive compounds. In this study, the early signaling effects of 3 were examined on Madin-Darby canine kidney (MDCK) cells loaded with the Ca(2+)-sensitive dye fura-2. It was found that 3 caused an immediate and sustained increase of [Ca(2+)](i) in a concentration-dependent manner (EC(50) = 40 μM). Compound 3 also induced a [Ca(2+)](i) elevation when extracellular Ca(2+) was removed, but the magnitude was reduced by 45%. In Ca(2+)-free medium, the 3-induced [Ca(2+)](i) level was abolished by depleting stored Ca(2+) with 1 μM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). Elevation of [Ca(2+)](i) caused by 3 in the Ca(2+)-containing medium was not affected by modulation of protein kinase C activity. The 3-induced Ca(2+) influx was inhibited by nifedipine and nicardipine (1 μM). U73122, an inhibitor of phospholipase C, abolished ATP (but not the 3-induced [Ca(2+)](i) level). These findings suggest that 3 induced a significant [Ca(2+)](i) elevation in MDCK renal tubular cells by stimulating both extracellular Ca(2+) influx and thapsigargin-sensitive intracellular Ca(2+) release via as yet unidentified mechanisms. Furthermore, the order of the allyl sulfide-induced [Ca(2+)](i) elevation and cell viability was 1 < 2 < 3. The differential effect of allyl sulfides on Ca(2+) signaling and cell death appears to correlate with the number of sulfur atoms in the structure of these allyl sulfides.

The garlic ingredient diallyl sulfide induces Ca2+ mobilization in Madin-Darby canine kidney cells.

Diallyl sulfide (DAS), one of the major organosulfur compounds (OSCs) of garlic, is recognized as a group of potential chemoproventive compounds. In this study, we examines the early signaling effects of DAS on renal cells loaded with Ca(2+)-sensitive dye fura-2. It was found that DAS caused an immediate and sustained rise of [Ca(2+)](i) in a concentration-dependent manner (EC(50)=2.32 mM). DAS also induced a [Ca(2+)](i) elevation when extracellular Ca(2+) was removed, but the magnitude was reduced by 45%. Depletion of intracellular Ca(2+) stores with CCCP, a mitochondrial uncoupler, did not affect DASs effect. In Ca(2+)-free medium, the DAS-induced [Ca(2+)](i) rise was abolished by depleting stored Ca(2+) with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). DAS-caused [Ca(2+)](i) rise in Ca(2+)-containing medium was not affected by modulation of protein kinase C activity. The DAS-induced Ca(2+) influx was blocked by nicardipine. U73122, an inhibitor of phospholipase C, abolished ATP (but not DAS)-induced [Ca(2+)](i) rise. Additionally, pretreatment with DAS for 24 h decreased cell viability in a concentration-dependent manner. Furthermore, DAS-induced cell death involved apoptotic events. These findings suggest that diallyl sulfide induced a significant rise in [Ca(2+)](i) in MDCK renal tubular cells by stimulating both extracellular Ca(2+) influx and thapsigargin-sensitive intracellular Ca(2+) release via as yet unidentified mechanisms.

Ca2+ movement and apoptosis induced by deltamethrin in Madin–Darby canine kidney canine renal tubular cells

This study explored the effect of deltamethrin, a pesticide, on free Ca2+ concentration [Ca2+]i, viability, and apoptosis in Madin–Darby canine kidney (MDCK) canine renal tubular cells. Deltamethrin at concentrations between 10μM and 40μM evoked [Ca2+]i rises in a concentration‐dependent manner. The Ca2+ entry was inhibited by nifedipine, econazole, phorbol 12‐myristate 13‐acetate, and SKF96365. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5‐di‐tert‐butylhydroquinone (BHQ) in a Ca2+‐free medium abolished deltamethrin‐induced [Ca2+]i rise. Treatment with deltamethrin also abolished BHQ‐induced [Ca2+]i rise. Inhibition of phospholipase C (PLC) activity with U73122 abolished deltamethrin‐evoked [Ca2+]i rise. Deltamethrin killed cells at 30–60μM in a concentration‐dependent manner. The cytotoxic effect of deltamethrin was not reversed by prechelating cytosolic Ca2+ with the acetoxymethyl ester of 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid. Annexin V/propidium iodide staining data suggest that 30–50μM deltamethrin induced apoptosis. Together, in MDCK renal tubular cells, deltamethrin induced [Ca2+]i rises that involved Ca2+ entry through protein kinase C‐mediated store‐operated Ca2+ channels, and PLC‐dependent Ca2+ release from the endoplasmic reticulum. Deltamethrin also induced Ca2+‐independent cell death that might involve apoptosis.

Effect of NPC-14686 (Fmoc-L-homophenylalanine) on intracellular Ca2+ levels in human hepatoma cells.

The effect of NPC-14686, a potential anti-inflammatory drug, on cytosolic free Ca(2+) levels ([Ca(2+)](i)) in HA22/VGH human hepatoma cells was explored by using fura-2 as a fluorescent Ca(2+) indicator. NPC-14686 at concentrations above 10 microM increased [Ca(2+)](i) in a concentration-dependent manner with an EC(50) value of 100 microM. The Ca(2+) signal was reduced by removing extracellular Ca(2+) or by 10 microM nifedipine and was not changed by verapamil or diltiazem. Pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) to deplete the endoplasmic reticulum Ca(2+) abolished 200 microM NPC-14686-induced Ca(2+) release; and conversely pretreatment with NPC-14686 abolished thapsigargin-induced Ca(2+) release. The Ca(2+) release induced by 200 microM NPC-14686 was not changed by inhibiting phospholipase C with 2 microM U73122. Together, the results suggest that in human hepatoma cells, NPC-14686 induced a [Ca(2+)](i) increase by causing store Ca(2+) release from the endoplasmic reticulum in an phospholipase C-independent manner, and by inducing nifedipine-sensitive Ca(2+) influx.

Effect of deoxycholic acid on Ca2+ movement, cell viability and apoptosis in human gastric cancer cells.

Abstract Deoxycholic acid (DOA) is one of the secondary bile acids used as a mild detergent for the isolation of membrane associated proteins. This study examined whether the secondary bile acid, DOA, altered Ca2+ movement, cell viability and apoptosis in SCM1 human gastric cancer cells. The Ca2+-sensitive fluorescent dye fura-2 was used to measure [Ca2+]i. DOA-evoked [Ca2+]i rises concentration dependently. The response was reduced by removing extracellular Ca2+. DOA-evoked Ca2+ entry was inhibited by store-operated Ca2+ channel inhibitors (nifedipine, econazole and SKF96365), the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate (PMA) and the PKC inhibitor GF109203X. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) abolished DOA-evoked [Ca2+]i rises. Conversely, treatment with DOA abolished TG-evoked [Ca2+]i rises. Inhibition of phospholipase C with U73122 abolished DOA-evoked [Ca2+]i rises. At 100–500 μM, DOA decreased cell viability, which was not changed by chelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). DOA between 100 and 300 μM also induced apoptosis. Collectively, in SCM1 cells, DOA-induced [Ca2+]i rises by evoking phospholipase C-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via store-operated Ca2+ channels. DOA also caused Ca2+-independent apoptosis.

Triethyltin increases cytosolic Ca2+ levels in human osteoblasts

In human osteosarcoma MG63 cells, effect of triethyltin, an environmental toxicant, on intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured by using fura-2. Triethyltin (1-50 μM) caused a rapid and sustained plateau rise of [Ca(2+)](i) in a concentration-dependent manner (EC(50)=10 μM). Triethyltin-induced [Ca(2+)](i) rise was prevented by 50% by removal of extracellular Ca(2+) but was not altered by voltage-gated Ca(2+) channel blockers. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum (ER) Ca(2+)-ATPase, caused a monophasic [Ca(2+)](i) rise, after which the increasing effect of triethyltin on [Ca(2+)](i) was attenuated by 60%; also, pretreatment with triethyltin abolished thapsigargin-induced [Ca(2+)](i) increase. Depletion of mitochondrial Ca(2+) with carbonylcyanide m-chlorophenylhydrazone (CCCP; 2 μM) did not affect triethyltin-induced Ca(2+) release. U73122, an inhibitor of phoispholipase C, abolished ATP (but not triethyltin)-induced [Ca(2+)](i) rise. A low concentration (1 μM) of triethyltin failed to alter ATP and bradykinin-induced [Ca(2+)](i) rises. These findings suggest that triethyltin rapidly increases [Ca(2+)](i) in osteoblasts by stimulating both extracellular Ca(2+) influx and intracellular Ca(2+) release via as yet unidentified mechanism(s).

Secondary metabolites from the stems of Artocarpus heterophyllus

(52), 403 (11),377 (13), 321 (100).1) School of Medicine and Health Sciences, Fooyin University, Kaohsiung, Taiwan 831, R.O.C., e-mail:low463@gmail.com; 2) Bioresource Collection and Research Center (BCRC), Food Industry Research and DevelopmentInstitute (FIRDI), Hsinchu, Taiwan 300, R.O.C., e-mail: cmj0404@gmail.com. Published in Khimiya Prirodnykh Soedinenii,No. 4, pp. 538–539, July–August, 2010. Original article submitted March 23, 2009.