High‐affinity binding sites for 12(S)‐hydroxy‐5,8,10,14‐eicosatetraenoic acid (12(S)‐HETE) in carcinoma cells

Abstract
12(S)‐hydroxy‐5,8,10,14‐eicosatetraenoic acid (12(S)‐HETE) enhances tumor cell adhesion to endothelial cells [Honn et al. (1988) Proc. Soc. Exp. Biol. Med. 189, 130–135]. The effect is correlated to surface expression of an integrin receptor, GpIIb/IIIa. Here, we describe evidence for high‐affinity binding of 12(S)‐HETE to Lewis lung carcinoma cells. Scatchard plot analyses indicated a single class of sites with apparent K d and B max values of 0.44 nM and 66,000 sites per cell, respectively. Competition experiments with unlabeled compounds shod d that the binding was reversible and saturable as well as stereo‐ and regiospecific. The 12(S)‐HETE binding, demonstrated here, might be an important step in a series of events controlling surface expression of integrin receptors.