Characterization of calcium-mobilizing, purinergic P2Y(2) receptors in human ovarian cancer cells

In human ovarian EFO-21 and EFO-27 carcinoma cells, extracellular ATP induc ed a concentration-dependent rise in intracellular calcium concentration ([ Ca2+](i)). suggesting the expression of a purinoreceptor. ATP and UTP were equipotent in generating [Ca2+](i) signals, followed by ATP-gamma-S and ADP , whereas beta,gamma-ATP, 2 methyl 1 thio-ATP, 3'-o-(4-benzoyl) benzoyl-ATP , AMP, and adenosine were ineffective. This pharmacological profile suggest ed the presence of the P2Y(2) subtype in both cell types, and this was conf irmed by reverse transcription-polymerase chain reaction (RT-PCR) analysis using P2Y(2) primers. ATP-induced [Ca2+](i) signals were composed of two ph ases: an early and extracellular calcium-independent phase, followed by a s ustained plateau phase that was dependent on capacitative calcium influx. I n addition to the rise in the [Ca2+](i), a time- and concentration-dependen t increase in phosphatidylethanol accumulation was observed in ATP-stimulat ed cells, indicating an increase in phospholipase D activity. RT-PCR analys is identified the expression of a transcript for the phospholipase D-1 subt ype of this enzyme. Activation of these receptors by a slowly degradable an alogue, ATP-gamma-S, attenuated basal and fetal calf serum-induced cell pro liferation in a time- and concentration-dependent manner. These results ind icate that ATP may act as an extracellular messenger in controlling the ova rian epithelial cell cycle through P2Y(2) receptors.