Thromboxane A2analogue U 46619 enhances tumour cell proliferation in HeLa cells via specific receptors which are apparently distinct from TXA2receptors on human platelets

Abstract

In this study, we have demonstrated for the first time by using U 46619, a stable analogue of thromboxane A₂ (TXA₂), that TXA₂ exerts a cell proliferative effect on HeLa cells which is mediated by specific TXA₂ receptors, inasmuch as the cell proliferation could be dose-dependently suppressed by TXA₂ receptor antagonist BM 13177. The investigation of the phospholipase C pathway by U 46619 and prostaglandin H₂(PGH₂) in the presence and absence of BM 13177 in cells with or without pertussis toxin pretreatment, as well as radioligand receptor binding studies, revealed that, in contrast to TXA₂ receptors on human platelets, where TXA₂ and PGH₂ share the same receptor binding sites, HeLa cells possess distinct receptors for TXA₂ and PGH₂.