Abstract
15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) is a potent anti-angiogenic factor and induces endothelial cell apoptosis, although the mechanism remains unclear. In this study, 15d-PGJ(2) was found to increase p53 levels of the human umbilical vein endothelial cells by stabilizing p53. Both 15d-PGJ(2)-induced apoptosis and the induction of p21(Waf1) and Bax can be abolished by p53 small interfering RNA but not by peroxisome proliferator-activated receptor gamma inhibitors. Moreover, 15d-PGJ(2) activated JNK and p38 MAPK while inducing p53 phosphorylation at sites responsible for p53 activity. JNK inhibitor (SP600125) or p38 MAPK inhibitor (SB203580) pretreatment attenuated 15d-PGJ(2)-mediated apoptosis and suppressed the p21(Waf1) and Bax expressions without affecting p53 protein accumulation. Pretreatment with SP600125 partially prevented the phosphorylation of p53 at serines 33 and 392 induced by 15d-PGJ(2). 15d-PGJ(2) was also found to induce reactive oxygen species generation and partially blocked nuclear factor-kappaB activity. Pretreatment with antioxidant N-acetylcysteine prevented the p53 accumulation, the phosphorylations of JNK and p38 MAPK, the inhibition of NF-kappaB activity, as well as the apoptosis induced by 15d-PGJ(2). Using a mouse model of corneal neovascularization, it was demonstrated in vivo that 15d-PGJ(2) induced reactive oxygen species generation, activated JNK and p38 MAPK, induced p53 accumulation/phosphorylation, and induced vascular endothelial cell apoptosis, which could be abolished by N-acetylcysteine, SP600125, SB203580, or a virus-derived amphipathic peptides-based p53 small interfering RNA. This is the first study that 15d-PGJ(2) induces vascular endothelial cell apoptosis through the signaling of JNK and p38 MAPK-mediated p53 activation both in vitro and in vivo, further establishing the potential of 15d-PGJ(2) as an anti-angiogenesis agent.