Differences in intracellular calcium mobilization by interferon-beta and interferon-gamma in RPMI-4788 cells.
Human interferon (IFN) stimulates a 1.5- to 1.7-fold transient increase in the concentration of cytoplasmic-free calcium ion ([Ca2+]i) within 10-20 s upon exposure of RPMI-4788 cells to IFN. This early event of IFN-induced [Ca2+]i mobilization was measurable by loading the cells with Fura-2AM, a fluorescent Ca2+ indicator. The mobilization induced by IFN-beta or IFN-gamma was dependent on the concentration of each IFN. The increased [Ca2+]i gradually returned to its resting level within 60 s. The addition of EGTA (0.5-10 mM) to medium induced a marked decrease in the amount of [Ca2+]i mobilized by IFN-beta and a partial decrease by IFN-gamma. This finding suggests that the mechanisms of [Ca2+]i mobilization by IFN-beta and IFN-gamma might be different. While IFN-beta-induced mobilization may be mainly from an influx of the extracellular calcium ion ([Ca2+]o), IFN-gamma-induced mobilization may be a summation of an influx of [Ca2+]o and a release from intracellular Ca2+ stores.
Miyake
M
M
First Department of Surgery, Okayama University Medical School, Japan.
Fuchimoto
S
S
Orita
K
K
D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology
D007370:Interferon Type I; D007371:Interferon-gamma; D002118:Calcium