Oligonucleotide NX1838 inhibits VEGF(165)-mediated cellular responses in vitro

VEGF (vascular endothelial growth factor) overproduction has been identifie d as a major factor underlying pathological angiogenesis in vivo, including such conditions as psoriasis, macular degeneration, and tumor proliferatio n. Endothelial cell tyrosine kinase receptors, KDR and Flt-1, have been imp licated in VEGF responses including cellular migration, proliferation, and modulation of vascular permeability Therefore, agents that limit VEGF-cellu lar interaction are likely therapeutic candidates for VEGF-mediated disease states (particularly agents blocking activity of VEGF(165), the most frequ ently occurring VEGF isoform). To that end, a nuclease-resistant, VEGF(165) -specific aptamer NX1838 (2'-fluoropyrimidine, RNA-bas ed oligonucleotide/4 0-kDa-PEG) was developed. We have as sess ed NX 1838 inhibition of a variet y of cellular events associated with VEGF, including cellular binding, sign al transduction, calcium mobilization, and induction of cellular proliferat ion Our data indicate that NX1838 inhibits binding of VEGF to HUVECs (human umbilical vein endothelial cells) and dose-dependently prevents VEGF-media ted phosphorylation of KDR and PLC gamma, calcium flux, and ultimately VEGF -induced cell proliferation. NX1838-inhibition of VEGF-mediated cellular ev ents was comparable to that observed with anti-VEGF monoclonal antibody, bu t was ineffective as an inhibitor of VEGF(121)-induced HUVEC proliferation. These findings, coupled with nuclease stability of the molecule, suggest t hat NX1838 may provide therapeutic utility in vivo.