Abstract
The effect of the natural product 3,3'-diindolylmethane (DIM) on cytosolic Ca 2+ concentrations ([Ca 2+] i) and viability in MG63 human osteosarcoma cells was explored. The Ca 2+-sensitive fluorescent dye fura-2 was applied to measure [Ca 2+] i. DIM at concentrations of 40-80μM induced a [Ca 2+] i rise in a concentration-dependent manner. The response was reduced partly by removing Ca 2+. 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 inhibitors thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) inhibited or abolished DIM-induced [Ca 2+] i rise. Incubation with DIM also inhibited thapsigargin or BHQ-induced [Ca 2+] i rise. Inhibition of phospholipase C with U73122 abolished DIM-induced [Ca 2+] i rise. At concentrations of 10-50μM, DIM killed cells in a concentration-dependent manner. This cytotoxic effect was not altered by chelating cytosolic Ca 2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Annexin V/propidium iodide staining data implicate that DIM (20 and 40μM) induced apoptosis in a concentration-dependent manner. In sum, in MG63 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 caused cell death that may involve apoptosis.
Original language | English |
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Pages (from-to) | 314-321 |
Number of pages | 8 |
Journal | Basic and Clinical Pharmacology and Toxicology |
Volume | 110 |
Issue number | 4 |
DOIs | |
State | Published - 04 2012 |
Externally published | Yes |