文摘
The effect of diindolylmethane, a natural compound derived from indole-3-carbinol in cruciferous vegetables, on cytosolic Ca2+ concentrations ([Ca2+]i) and viability in HA59T human hepatoma cells is unclear. This study explored whether diindolylmethane changed [Ca2+]i in HA59T cells. The Ca2+-sensitive fluorescent dye fura-2 was applied to measure [Ca2+]i. Diindolylmethane at concentrations of 1-0?μM evoked a [Ca2+]i rise in a concentration-dependent manner. The signal was reduced by removing Ca2+. Diindolylmethane-induced Ca2+ influx was not inhibited by nifedipine, econazole, SK&F96365, and protein kinase C modulators but was inhibited by aristolochic acid. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitors thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) inhibited or abolished diindolylmethane-induced [Ca2+]i rise. Incubation with diindolylmethane inhibited thapsigargin or BHQ-induced [Ca2+]i rise. Inhibition of phospholipase C with U73122 reduced diindolylmethane-induced [Ca2+]i rise. At concentrations of 10-5?μM, diindolylmethane killed cells in a concentration-dependent manner. The cytotoxic effect of diindolylmethane was not reversed by chelating cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N-N-tetraacetic acid. Propidium iodide staining data suggest that diindolylmethane (25-0?μM) induced apoptosis in a concentration-dependent manner. Collectively, in HA59T cells, diindolylmethane induced a [Ca2+]i rise by causing phospholipase C-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ influx via phospholipase A2-sensitive channels. Diindolylmethane induced cell death that may involve apoptosis.