PRX-08066 is a selective antagonist of 5-hydroxytryptamine receptor 2B (5-HT2BR) with Ki value of 3.4nM [1].
PRX-08066 is found to causes selective vasodilation of pulmonary arteries and is developed to treat for pulmonary arterial hypertension (PAH). In the in vitro studies, PRX-08066 shows effects on the vascular muscularization induced by 5-HT. It inhibits 5-HT induced mitogen-activated protein kinase activation with IC50 value of 12nM. In addition, it significantly reduces thymidine incorporation in CHO cells expressing human 5-HT2BR with IC50 value of 3nM. In both mice and rat models, PRX-08066 reverses the hypoxia-dependent increase in right ventricular systolic pressure. Besides that, PRX-08066 is also found to have anti-proliferative and anti-fibrotic effects. It inhibits the secretion of 5-HT, the phosphorylation of ERK1/2 and synthesis of profibrotic growth factor. Moreover, PRX-08066 inhibits the proliferation of the small intestinal neuroendocrine tumor cell line KRJ-I with IC50 value of 4.6nM [1, 2].
References:
[1] Porvasnik S L, Germain S, Embury J, et al. PRX-08066, a novel 5-hydroxytryptamine receptor 2B antagonist, reduces monocrotaline-induced pulmonary arterial hypertension and right ventricular hypertrophy in rats. Journal of Pharmacology and Experimental Therapeutics, 2010, 334(2): 364-372.
[2] Svejda B, Kidd M, Giovinazzo F, et al. The 5-HT2B receptor plays a key regulatory role in both neuroendocrine tumor cell proliferation and the modulation of the fibroblast component of the neoplastic microenvironment. Cancer, 2010, 116(12): 2902-2912.