A New Class of Dengue and West Nile Virus Protease Inhibitors with Submicromolar Activity in Reporter Gene DENV‑2 Protease and Viral Replication Assays

Dengue and West Nile virus are rapidly
spreading global pathogens
for which no specific therapeutic treatments are available. One of
the promising targets for drug discovery against dengue and other
flaviviruses is the viral serine protease NS2B-NS3. We present the
design, synthesis, and in vitro and cellular characterization of a
novel chemotype of potent small-molecule non-peptidic dengue protease
inhibitors derived from 4-benzyloxyphenylglycine. A newly developed
luciferase-based DENV-2 protease reporter system in HeLa cells (DENV2proHeLa) was employed to determine
the activity of the compounds in a cellular environment. Specificity
and selectivity of the DENV2proHeLa system were confirmed by viral
titer reduction assays. The compounds reach low micromolar to upper
nanomolar inhibitory potency in cell-based assays, are selective against
other serine proteases, and do not show relevant cytotoxicity. An
extensive structure–activity relationship study provides a
perspective for further drug development against flaviviral infections.