ABSTRACT
West Nile virus (WNV) has spread rapidly around the globe, efficiently crossing species from migrating birds into humans and other mammals. The viral protease NS2B-NS3 is important for WNV replication and recognizes dibasic substrate sequences common to other flaviviral proteases but different from most mammalian proteases. Potent inhibitors of WNV protease with antiviral activity have been elusive to date. We report the smallest and most potent inhibitors known for this enzyme, cationic tripeptides with nonpeptidic caps at the N-terminus and aldehyde at the C-terminus. One of these, compound 3 ( Ki = 9 nM) is stable in serum (>90% intact after 3 h, 37 degrees C), cell permeable, and shows antiviral activity (IC 50 1.6 microM) without cytotoxicity (IC 50 >400 microM), thereby validating the approach of inhibiting WNV protease to suppress WNV replication.
Subject(s)
Antiviral Agents/pharmacology , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/blood , Antiviral Agents/chemistry , Cations , Models, Molecular , Protease Inhibitors/blood , Protease Inhibitors/chemistry , RNA Helicases/antagonists & inhibitors , RNA Helicases/chemistry , RNA Helicases/metabolism , Serine Endopeptidases/chemistry , Serine Endopeptidases/metabolism , Substrate Specificity , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolismABSTRACT
Vascular endothelial growth inhibitor (VEGI) is a novel anti-angiogenic cytokine that belongs to the tumour necrosis factor (TNF) superfamily. Very little is known about the significance of VEGI in cancer. Our study analysed VEGI expression in relation to breast cancer patient clinical parameters. The VEGI expression profile was assessed qualitatively (RT-PCR), quantitatively (real-time Quantitative-PCR), and immuno-histochemically (IHC), in a panel of 24 human normal and cancer cell lines and in a cohort of 151 mammary tissue samples (n = 33 normal breast tissue; n = 118 breast cancer tissue) with a 6-year median follow-up. Patients who had died of breast cancer or had local recurrence of the disease expressed significantly lower levels of VEGI in comparison to the elevated levels in the disease free patients. High levels of VEGI were associated with an increased chance of patient survival. Importantly, patients with breast tumours expressing reduced levels of VEGI had a poorer prognosis than those patients expressing high levels of VEGI. However, no significant correlations were observed between VEGI expression and tumour grade, TNM classification, or nodal involvement. In conclusion, VEGI is aberrantly expressed in human breast cancer tissues. VEGI displays prognostic relevance as breast cancer patients with an overall poor prognosis express significantly lower levels of VEGI compared to those with a favourable prognosis.
