Ether lipid-induced cell damage of neuroblastoma cells is only weakly correlated with increased intracellular Ca2+ levels.
The cell-damaging action of the ether lipid ET-18-OCH3 was studied in single NH15-CA2 neuroblastoma x glioma hybrid cells using light microscopy, and correlated with changes of the free intracellular calcium concentration, [Ca2+]i, as measured with the fluorescent Ca2+ indicator Fura-2. Addition of 3-100 microM ET-18-OCH3 to the cultures caused disintegration of neurites, cell rounding and detachment of the cells from the bottom of the culture dish. The effects occurred within 30-240 min, the faster, the higher the ET-18-OCH3 concentration. Also [Ca2+]i increased in a concentration-dependent manner, however, within seconds, and stayed high during the recording time of 20 min. The presence of 50 microM lanthanum or gadolinium ions prevented the ET-18-OCH3-induced increases of [Ca2+]i, but had no effect on neurite destruction and cell rounding. Preincubation with 1 mM diisopropylfluorphosphate or 100 microM leupeptin, both membrane-permeant inhibitors of intracellular proteases, did not prevent the effects. Nor was neurite destruction prohibited in the presence of 10 microM of the actin-stabilizing agent phalloidin or 2 microM taxol, a microtubule-stabilizer. We conclude that [Ca2+]i, although being increased during ET-18-OCH3-induced cell damage, is not the key factor of cell destruction.
Brinkmeier
H
H
Department of General Physiology, University of Ulm, Germany. Heinrich.brinkmeier@medizin.uni-ulm.de
Schneider
M
M
Rüdel
R
R
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006822:Hybrid Cells; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D010742:Phospholipid Ethers / Q000494:pharmacology*; D051381:Rats; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D010742:Phospholipid Ethers; C026659:edelfosine; D002118:Calcium