Diethylstilbestrol-Induced Estrogen Receptor-Dependent [Ca2+]iRises and Apoptosis in Chinese Hamster Ovary (CHO) Cells

Comparison of cytotoxicity induced by 17α-ethynylestradiol and diethylstilbestrol in fish CCO and mammalian CHO-K1 cell lines

The effects of synthetic estrogens 17α-ethynylestradiol (EE2) and diethylstilbestrol (DES) were compared on cell proliferation and morphology in Channel Catfish Ovary (CCO) and Chinese Hamster Ovary (CHO-K1) cells. EE2 exposure (0.1 and 0.5 μg/mL) induced stimulatory effect on CCO and CHO-K1 cell proliferation, while higher concentrations (1-10 μg/mL) showed cytotoxic effects. Increase in DES concentrations mainly resulted in dose-depended increase in cytotoxicity in both cell lines. Morphological changes induced by EE2 and DES exposure (5 μg/mL) showed disrupted cell monolayer and increased number and size of lysosomes. Comparison of IC(50) values showed almost equal sensitivity towards cytotoxicity of tested compounds in CCO and CHO-K1 cells.

Oxidatively damaged proteins in the early stage of testicular toxicities in male rats by orally administered with a synthetic oestrogen, diethylstilbestrol

The molecular mechanism of severe adverse effects of the endocrine disruptor diethylstilbestrol (DES) on reproductive organs is not currently understood. The effects of DES on testicular proteins were studied in adult male rats orally treated with 0.35 and 3.5mg DES/kg every two days for two weeks before the manifestation of morphological toxicities. Two up-regulated proteins (glutamine synthetase and chaperonin containing TCP1), two down-regulated proteins (thioredoxin-like 1 and testis-specific autoantigen) and two proteins with altered isoelectric points (protein disulfide isomerase [PDI a3] and enolase 1) were identified in DES groups. Carbonylation of PDI a3 was detected. A significant decrease in PDI activity and significant increases in caspase-12 and calpain activities were also found in the group. It is suggested that testicular toxicity by DES was initiated by the down-regulation of thioredoxin-like-1 leading to the cellular redox inbalances, and the resultant oxidative modification of several important proteins involved in protein foldings.

Effect of [6]-shogaol on cytosolic Ca2+ levels and proliferation in human oral cancer cells (OC2)

The effect of [6]-shogaol (1) on cytosolic free Ca(2+) concentrations ([Ca(2+)](i)) and viability has not been explored previously in oral epithelial cells. The present study has examined whether 1 alters [Ca(2+)](i) and viability in OC2 human oral cancer cells. Compound 1 at concentrations > or = 5 microM increased [Ca(2+)](i) in a concentration-dependent manner with a 50% effective concentration (EC(50)) value of 65 microM. The Ca(2+) signal was reduced substantially by removing extracellular Ca(2+). In a Ca(2+)-free medium, the 1-induced [Ca(2+)](i) elevation was mostly attenuated by depleting stored Ca(2+) with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). The [Ca(2+)](i) signal was inhibited by La(3+) but not by L-type Ca(2+) channel blockers. The elevation of [Ca(2+)](i) caused by 1 in a Ca(2+)-containing medium was not affected by modulation of protein kinase C activity, but was inhibited by 82% with the phospholipase A2 inhibitor aristolochic acid I (20 microM). U73122, a selective inhibitor of phospholipase C, abolished 1-induced [Ca(2+)](i) release. At concentrations of 5-100 microM, 1 killed cells in a concentration-dependent manner. These findings suggest that [6]-shogaol induces a significant rise in [Ca(2+)](i) in oral cancer OC2 cells by causing stored Ca(2+) release from the thapsigargin-sensitive endoplasmic reticulum pool in an inositol 1,4,5-trisphosphate-dependent manner and by inducing Ca(2+) influx via a phospholipase A2- and La(3+)-sensitive pathway.