Ki16425 is a competitive, potent and reversible antagonist to LPA1, LPA2 and LPA3 with Ki of 0.34 M, 6.5 M and 0.93 M, respectively, shows no activity at LPA4, LPA5, LPA6.
Kil6425 preferentially inhibits LPA1- and LPA3-mediated responses but has only a moderate effect on LPA2. Ki16425 inhibits the LPA-induced Ca(2+) response in THP-1 cells, 3T3 fibroblasts, and A431 cells, but had only a marginal effect in PC-12 cells and HL-60 cells, which means that Ki16425 seems to be a useful tool for evaluating the involvement of specific LPA receptors in the short-term response to LPA. Ki16425 inhibits long-term DNA synthesis and cell migration as induced by LPA in Swiss 3T3 fibroblasts . Ki16425 reduces the LPA-induced activation of p42/p44 mitogen activated protein kinase (MAPK), while acting as a weak stimulator of p42/p44 MAPK on its own, properties typical of a protean agonist. Ki16425 also significantly reduces the NGF-induced stimulation of p42/p44 MAPK and inhibited NGF-stimulated neurite outgrowth in PC-12 cells .