A novel tumour promoter, thapsigargin, transiently increases cytoplasmic free Ca2+ without generation of inositol phosphates in NG115-401L neuronal cells

TY - JOUR

T1 - A novel tumour promoter, thapsigargin, transiently increases cytoplasmic free Ca2+ without generation of inositol phosphates in NG115-401L neuronal cells

AU - Jackson, T R

AU - Patterson, S I

AU - Thastrup, Ole

AU - Hanley, M R

PY - 1988

Y1 - 1988

N2 - Thapsigargin, a sesquiterpene lactone with potent irritant and tumour-promoting activities, stimulates a rapid (within 15 s) transient increase in intracellular [Ca2+] in the NG115-401L neural cell line, as measured by the fluorescent indicator dye fura-2. This increase in cytoplasmic free [Ca2+] is concentration-dependent (ED50 around 20 nM) and occurs in the absence of extracellular Ca2+. Activation of NG115-401L cells by the inflammatory peptide bradykinin generates inositol phosphates, which parallel increases in intracellular [Ca2+]. However, the rise in cytoplasmic [Ca2+] stimulated by thapsigargin occurs in the absence of detectable production of inositol phosphates. Thapsigargin is unlike phorboid tumour promoters in that it has no action on two non-invasive indicators of phorbol stimulation of these cells, i.e. [3H]choline metabolite production and rise in intracellular pH. These data suggest that thapsigargin releases Ca2+ from an intracellular store by a novel mechanism, independent of the hydrolysis of phosphoinositides and concomitant activation of protein kinase C. Thus thapsigargin may provide a valuable tool for the analysis of intracellular signalling mechanisms.

AB - Thapsigargin, a sesquiterpene lactone with potent irritant and tumour-promoting activities, stimulates a rapid (within 15 s) transient increase in intracellular [Ca2+] in the NG115-401L neural cell line, as measured by the fluorescent indicator dye fura-2. This increase in cytoplasmic free [Ca2+] is concentration-dependent (ED50 around 20 nM) and occurs in the absence of extracellular Ca2+. Activation of NG115-401L cells by the inflammatory peptide bradykinin generates inositol phosphates, which parallel increases in intracellular [Ca2+]. However, the rise in cytoplasmic [Ca2+] stimulated by thapsigargin occurs in the absence of detectable production of inositol phosphates. Thapsigargin is unlike phorboid tumour promoters in that it has no action on two non-invasive indicators of phorbol stimulation of these cells, i.e. [3H]choline metabolite production and rise in intracellular pH. These data suggest that thapsigargin releases Ca2+ from an intracellular store by a novel mechanism, independent of the hydrolysis of phosphoinositides and concomitant activation of protein kinase C. Thus thapsigargin may provide a valuable tool for the analysis of intracellular signalling mechanisms.

KW - Bradykinin

KW - Calcimycin

KW - Calcium

KW - Cell Line

KW - Choline

KW - Digitonin

KW - Inositol Phosphates

KW - Intracellular Fluid

KW - Neurons

KW - Plant Extracts

KW - Plants, Medicinal

KW - Spectrometry, Fluorescence

KW - Sugar Phosphates

KW - Thapsigargin

M3 - Journal article

C2 - 3138987

SN - 0264-6021

VL - 253

SP - 81

EP - 86

JO - Biochemical Journal

JF - Biochemical Journal

IS - 1

ER -