Depletion of intracellular calcium stores is toxic to SH-SY5Y neuronal cells.
Inhibiting Ca(2+) uptake by the sarcoendoplasmic reticular Ca(2+)-ATPase pump (SERCA) causes release of Ca(2+) from the endoplasmic reticulum (ER), increased cytosolic Ca(2+) ([Ca(2+)](cyt)) and depletion of ER Ca(2+) stores. These studies were designed to test the effects of SERCA inhibition on neuronal viability, using as a model the human neuroblastoma cell line, SH-SY5Y. Continuous exposure to the SERCA inhibitor thapsigargin (TG) decreased SH-SY5Y viability to <30% after 48 h exposure, and produced DNA laddering. Two other SERCA inhibitors, BHQ and cyclopiazonic acid CPA, were similarly toxic, although at 1000-fold higher concentrations. BHQ and CPA toxicity was prevented by removing drug within several hours, whereas TG toxicity was essentially irreversible. All three SERCA inhibitors caused an increase in [Ca(2+)](cyt) that was partially blocked by the ryanodine receptor inhibitors, dantrolene and DHBP. Pretreatment with 40 microM dantrolene gave substantial protection against TG- or BHQ-induced cell death but it did not inhibit death from staurosporine, which does not cause release of ER Ca(2+). DHBP (20-100 microM) also gave partial protection against TG toxicity, as did ruthenium red (2 microM), but not ryanodine (10 microM). Inhibition of capacitative Ca(2+) entry with EGTA or LaCl(3) or low extracellular Ca(2+), or chelation of [Ca(2+)](cyt) with BAPTA-AM, failed to inhibit TG toxicity, although they prevented increases in [Ca(2+)](cyt) caused by TG. Taken together, these data suggest that toxicity caused by SERCA inhibition in SH-SY5Y cells is caused by ER Ca(2+) depletion, which triggers an apparent apoptotic pathway.
Nguyen
Henry N
HN
Department of Pharmacology, George Washington University Medical Center, 2300 I St. NW, 20037, Washington, DC, USA
Wang
Chen
C
Perry
David C
DC
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002545:Brain Ischemia / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D003600:Cytosol / Q000378:metabolism; D003620:Dantrolene / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009447:Neuroblastoma; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D012717:Sesquiterpenes / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D006873:Hydroquinones; D007211:Indoles; D009125:Muscle Relaxants, Central; D012717:Sesquiterpenes; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C019359:2,5-di-tert-butylhydroquinone; C006438:alatolide; D004533:Egtazic Acid; D019284:Thapsigargin; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D003620:Dantrolene; D019311:Staurosporine; D002118:Calcium; C000543:cyclopiazonic acid