title: Effect of diindolylmethane on Ca(2+) homeostasis and viability in MDCK renal tubular cells.
abstract: The effect of the natural product diindolylmethane (DIM) on cytosolic Ca(2+) concentrations ([Ca(2+)]i) and viability in MDCK renal tubular cells was explored. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)]i. DIM at concentrations 1-50 μM induced a [Ca(2+)]i rise in a concentration-dependent manner. The response was reduced partly by removing Ca(2+). DIM induced Mn(2+) influx leading to quenching of fura-2 fluorescence. DIM-evoked Ca(2+) entry was suppressed by nifedipine, econazole, SK&F96365 and protein kinase C modulators. In the absence of extracellular Ca(2+), incubation with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (TG) or 2,5-di-tert-butylhydroquinone (BHQ) greatly inhibited DIM-induced [Ca(2+)]i rise. Incubation with DIM abolished TG or BHQ-induced [Ca(2+)]i rise. Inhibition of phospholipase C with U73122 reduced DIM-induced [Ca(2+)]i rise by 50%. At 1, 10, 40 and 50 μM, DIM slightly enhanced cell proliferation. The effect of 50 μM DIM was reversed by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. In sum, in MDCK cells, DIM induced a [Ca(2+)]i rise by evoking phospholipase C-dependent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via protein kinase C-sensitive store-operated Ca(2+) channels. DIM did not induce cell death.
authors.affiliation: Department of Laboratory Medicine, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan.
authors.forename: Y-C
authors.initials: YC
authors.lastname: Fang
authors.forename: C-T
authors.initials: CT
authors.lastname: Chou
authors.forename: C-C
authors.initials: CC
authors.lastname: Chi
authors.forename: K-L
authors.initials: KL
authors.lastname: Lin
authors.forename: Y-D
authors.initials: YD
authors.lastname: Li
authors.forename: H-H
authors.initials: HH
authors.lastname: Cheng
authors.forename: Y-C
authors.initials: YC
authors.lastname: Lu
authors.forename: J-S
authors.initials: JS
authors.lastname: Cheng
authors.forename: C-C
authors.initials: CC
authors.lastname: Kuo
authors.forename: C-R
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000818:Animals; D001688:Biological Products / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology*; D007684:Kidney Tubules / Q000166:cytology; D061985:Madin Darby Canine Kidney Cells; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D001688:Biological Products; D007211:Indoles; D010738:Type C Phospholipases; C016392:3,3'-diindolylmethane; D002118:Calcium