Effect of diethylstilbestrol on Ca2+ handling and cell viability in human breast cancer cells.
In human breast cancer cells, the effect of the widely prescribed estrogen diethylstilbestrol (DES) on intracellular Ca2+ concentrations ([Ca2+]i) and cell viability was explored by using fura-2 and trypan blue exclusion, respectively. DES caused a rise in [Ca2+]i in a concentration-dependent manner (EC50 = 15 microM). DES-induced [Ca2+]i rise was reduced by 80 % by removal of extracellular Ca2+. DES-induced Mn(2+)-associated quench of intracellular fura-2 fluorescence also suggests that DES induced extracellular Ca2+ influx. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a monophasic [Ca2+]i rise, after which the increasing effect of DES on [Ca2+]i was greatly inhibited. Conversely, pretreatment with DES to deplete intracellular Ca2+ stores totally prevented thapsigargin from releasing more Ca2+, whereas ionomycin added afterward still released some Ca2+. These findings suggest that in human breast cancer cells, DES increases [Ca2+]i by stimulating extracellular Ca2+ influx and also by causing intracellular Ca2+ release from the endoplasmic reticulum. Acute trypan blue exclusion studies suggest that 10-20 NM DES killed cells in a time-dependent manner.
Chang
Hong-Tai
HT
Department of Surgery, Kaohsiung Veterans General Hospital Kaohsiung, Taiwan 813, Republic of China.
Hsu
Shu-Shong
SS
Chen
Jin-Shyr
JS
Lin
Ko-Long
KL
Wang
Jue-Long
JL
Cheng
He-Hsiung
HH
Lu
Yih-Chau
YC
Jiann
Bang-Ping
BP
Liu
Chun-Peng
CP
Huang
Jong-Khing
JK
Yeh
Jeng Hsien
JH
Chiang
An-Jen
AJ
Chen
Wei-Chuan
WC
Jan
Chung-Ren
CR
D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D001943:Breast Neoplasms; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D004054:Diethylstilbestrol / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D019284:Thapsigargin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D018931:Antineoplastic Agents, Hormonal; D004791:Enzyme Inhibitors; D019284:Thapsigargin; D004054:Diethylstilbestrol; D002118:Calcium