title: Nordihydroguaiaretic acid-induced Ca2+ handling and cytotoxicity in human prostate cancer cells.
abstract: The effect of nordihydroguaiaretic acid (NDGA), a compound commonly used as a lipoxygenases inhibitor, on intracellular free Ca2+ levels ([Ca2+]i) in PC3 human prostate cancer cells was investigated. [Ca2+]i was measured by using the Ca2+ -sensitive dye fura-2. NDGA increased [Ca2+]i in a concentration-dependent manner with an EC50 of 30 microM. The Ca2+ signal comprised a gradual and sustained increase. Removal of extracellular Ca2+ partly decreased the NDGA-induced [Ca2+]i increase, suggesting that the Ca2+ signal was due to both extracellular Ca2+ influx and intracellular Ca2+ release. NDGA-induced Ca2+ influx was independently confirmed by measuring NDGA-induced Mn2+ -coupled quench of fura-2 fluorescence. The NDGA-induced Ca2+ influx was not affected by L-type Ca2+ channel blockers. In Ca2+ -free medium, the NDGA-induced [Ca2+]i increase was abolished by pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), and conversely, pretreatment with NDGA abolished thapsigargin-induced [Ca2+]i increase. NDGA-induced intracellular Ca2+ release was not altered by inhibition of phospholipase C. Overnight treatment with 20-50 microM NDGA inhibited cell proliferation rate in a concentration-dependent manner. Several other lipoxygenases inhibitors did not alter [Ca2+]i. Collectively, this study shows that in prostate cells, NDGA induced a [Ca2+]i increase via releasing stored Ca2+ from the endoplasmic reticulum in a manner independent of phospholipase C activity, and by causing Ca2+ influx. NDGA also caused cytotoxicity at higher concentrations.
authors.affiliation: Department of Surgery, Kaohsiung Veterans General Hospital, Taiwan 813.
authors.forename: Jong-Khing
authors.initials: JK
authors.lastname: Huang
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Chen
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Huang
authors.forename: Shu-Shong
authors.initials: SS
authors.lastname: Hsu
authors.forename: Jin-Shyr
authors.initials: JS
authors.lastname: Chen
authors.forename: He-Hsiung
authors.initials: HH
authors.lastname: Cheng
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Bang-Ping
authors.initials: BP
authors.lastname: Jiann
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000970:Antineoplastic Agents; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003124:Colorimetry; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D008297:Male; D009637:Masoprocol / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D012996:Solutions; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D005456:Fluorescent Dyes; D016859:Lipoxygenase Inhibitors; D012996:Solutions; D009637:Masoprocol; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2