Fendiline-evoked [Ca2+]i rises and non-Ca2+-triggered cell death in human oral cancer cells.
The effect of fendiline on cytosolic free Ca(2+) concentrations ([Ca(2+)](i)) and proliferation has not been explored in human oral cancer cells. This study examined whether fendiline altered Ca(2+) levels and caused cell death in OC2 human oral cancer cells. [Ca(2+)](i) and cell viability were measured using the fluorescent dyes fura-2 and WST-1, respectively. Fendiline at concentrations above 10 microM increased [Ca(2+)](i) in a concentration-dependent manner. The Ca(2+) signal was reduced partly by removing extracellular Ca(2+). The fendiline-induced Ca(2+) influx was sensitive to blockade of L-type Ca(2+) channel blockers. In Ca(2+)-free medium, after pretreatment with 50 microM fendiline, 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor)-induced [Ca(2+)](i) rises were inhibited; and conversely, thapsigargin pretreatment nearly abolished fendiline-induced [Ca(2+)](i) rises. Inhibition of phospholipase C with 2 microM U73122 did not change fendiline-induced [Ca(2+)](i) rises. At concentrations between 5 and 25 microM, fendiline killed cells in a concentration-dependent manner. The cytotoxic effect of 15 microM fendiline was not reversed by prechelating cytosolic Ca(2+) with BAPTA/AM. Collectively, in OC2 cells, fendiline induced [Ca(2+)](i) rises by causing Ca(2+) release from the endoplasmic reticulum and Ca(2+) influx from L-type Ca(2+) channels. Furthermore, fendiline-caused cytotoxicity was not via a preceding [Ca(2+)](i) rise.
Department of Nursery, Tzu Hui Institute of Technology; Pingtung, Taiwan.
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D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005275:Fendiline / Q000494:pharmacology*; D005456:Fluorescent Dyes / Q000378:metabolism; D016257:Fura-2 / Q000378:metabolism; D006801:Humans; D009062:Mouth Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D009543:Nifedipine / Q000633:toxicity; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D013778:Tetrazolium Salts / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology
C110656:2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium; D002121:Calcium Channel Blockers; D004963:Estrenes; D005456:Fluorescent Dyes; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D013778:Tetrazolium Salts; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D004533:Egtazic Acid; D019284:Thapsigargin; D009543:Nifedipine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D005275:Fendiline; D002118:Calcium; D016257:Fura-2