The human neuroblastoma SK-SY5Y cell line bears functional endothelin-A-receptors and endothelin

The study reported here characterizes the presence both of endothelin (ET) receptors and of a synthesizing ET apparatus in the human neuroblastoma SK- SY5Y cell line. We demonstrated, using reverse transcriptase polymerase cha in reaction (RT-PCR), that these cells bound [I-125]ET-1. The potency order of ET analogs to inhibit [I-125]ET-1 binding was consistent with the prese nce of ETA-receptors. [Ca2+](i) was increased by both ET-1 and ET-3 (potenc y order: ET-1 > ET-3. The mRNAs of preproendothelin-1 and of endothelin con verting enzyme (ECE) were expressed by cells, as shown by RT-PCR studies. T hese mRNAs were translated into functional proteins as the cells were able to release mature (1-21) ET-like immunoreactivity into the culture medium. That secretion was time-dependent and was enhanced by treatment of the cell s by the phorbol ester 12-O-tetradecanoyl phorbol-13-acetate. These results show that the human SK-SY5Y neuroblastoma cell line produces mature ET whi ch could act as an autocrine/paracrine factor on these cells.