Unmodified calcium concentrations in tumour necrosis factor receptor subtype-mediated apoptotic cell death

Tumour necrosis factor-alpha (TNF) receptors mediate a variety of effects d ependent on cell type. A role for Ca2+ in TNF-induced death remains uncerta in. Here we investigated restricting intracellular/extracellular Ca2+ in He La epithelial carcinoma cells expressing low and high levels of p75TNFR rec eptor subtype and KYM-1 rhabdomyosarcoma cells, models of rapid TNF-induced apoptosis. Ca2+-chelators EGTA and BAPTA-AM as well as microsomal Ca2+-ATP ase inhibitor thapsigargin, did not alter TNF-induced death. TNF was also u nable to alter resting [Ca2+](i) levels which remained < 200 nM even during times when these cells were undergoing apoptotic cell death. These finding s indicate no role for modulated Ca2+ concentrations in TNF-induced apoptot ic cell death.