Effect of phenethyl isothiocyanate on Ca2+ movement and viability in MDCK canine renal tubular cells
Kaohsiung Veterans General Hospital, Taiwan.Human & Experimental Toxicology (Impact Factor: 1.75). 05/2012; 31(12). DOI: 10.1177/0960327112446841
The effect of the natural compound phenethyl isothiocyanate (PEITC) on cytosolic Ca(2+) concentrations ([Ca(2+)](i)) and viability in MDCK renal cells is unknown. This study explored whether PEITC changed [Ca(2+)](i) in MDCK cells using the Ca(2+)-sensitive fluorescent dye fura-2. PEITC at 200-700 μM increased [Ca(2+)](i) in a concentration-dependent manner. The signal was reduced by removing extracellular Ca(2+). PEITC-induced Ca(2+) influx was inhibited by nifedipine, econazole, SK&F 96365 and protein kinase C modulators. In Ca(2+)-free medium, treatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (TG) or 2,5-di-tert-butylhydroquinone (BHQ) inhibited PEITC-induced rise in [Ca(2+)](i). Incubation with PEITC also inhibited TG or BHQ-induced rise in [Ca(2+)](i). Inhibition of phospholipase C with U73122 abolished PEITC-induced rise in [Ca(2+)](i). At 15-75 μM, PEITC decreased viability. The cytotoxic effect of PEITC was enhanced by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester. Annexin V-FITC data suggest that 20 and 50 μM PEITC induced apoptosis. At 10 and 15 μM, PEITC did not increase reactive oxygen species (ROS) production. Together, in renal tubular cells, PEITC-induced rise in [Ca(2+)](i) by inducing phospholipase C-dependent Ca(2+) release from endoplasmic reticulum and Ca(2+) entry via store-operated Ca(2+) channels. PEITC induced apoptosis in a concentration-dependent, ROS/Ca(2+)-independent manner.
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ABSTRACT: Abstract The effect of angiotensin II (Ang II) on cytosolic Ca(2+) concentrations ([Ca(2+)]i) in MDCK renal tubular cells was explored. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)]i. Ang II at concentrations of 5-40 µM induced a [Ca(2+)]i rise in a concentration-dependent manner. The response was reduced partly by removing Ca(2+). Ang II evoked store-operated Ca(2+) entry that was inhibited by La(3+) and Gd(3+). In the absence of extracellular Ca(2+), incubation with the endoplasmic reticulum Ca(2+) pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) or thapsigargin abolished Ang II-induced Ca(2+) release. Inhibition of phospholipase C with U73122 abolished Ang II-induced [Ca(2+)]i rise. Three Ang II analogues [(ASN1,VAL5)-Ang II acetate, (SAR1,THR8)-Ang II acetate, (VAL5)-Ang II acetate] failed to induce a [Ca(2+)]i rise. Together, in MDCK cells, Ang II induced a [Ca(2+)]i rise via Ca(2+) entry through store-operated Ca(2+) channels and phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum. Moreover, Ang II's amino acid sequence is important in its stimulatory effect on [Ca(2+)]i.
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ABSTRACT: Beta-phenethyl isothiocyanate (PEITC) is an important phytochemical from cruciferous vegetables and is being evaluated for chemotherapeutic activity in early phase clinical trials. Moreover, studies in cell culture and in animals found that the anticarcinogenic activities of PEITC involved all the major stages of tumor growth: initiation, promotion and progression. A number of mechanisms have been proposed for the chemopreventive activities of this compound. Here, we focus on the major molecular signaling pathways for the anti-cancer activities of PEITC. These include (1) activation of apoptosis pathways; (2) induction of cell cycle arrest; and (3) inhibition of the survival pathways. Furthermore, we also discussed the regulation of drug-metabolizing enzymes, including cytochrome P450s, metabolizing enzymes and multidrug resistance.
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