01 Set Preliminary evaluation of antiviral activity of candidate HIV inhibitors targeting human DDX3 protein

Francesco Saladini

Human helicase DDX3 protein is an essential host factor for the replication of different viruses such as CMV, HIV-1, HBV, HCV, DENV, WNV. In this work we describe the evaluation of the anti-HIV activity of candidate DDX3 inhibitors through a phenotypic assay consisting in a first round of infection of MT-2 cells with HIV-1 NL4-3 strain in presence of serial dilutions of the investigational compounds, followed by a second round of infection of the reporter cell line TZM-bl with MT-2 supernatants. Similarly, antiviral activity was further evaluated against a panel of HIV-1 recombinant viruses carrying mutations conferring resistance to drugs approved for HIV-1 treatment. Thirty one candidate DDX3 inhibitors were tested through the BiCycle Assay and 10/31 molecules showed a weak activity against NL4-3 strain (IC50 > 50 μM), while 9/31 compounds had IC50 values in the low micromolar range (0.2 – 3 μM). One of these most active inhibitors retained full activity against six HIV-1 viral clones resistant to PIs, NRTIs, NNRTIs and INIs (fold change values range 0.2 – 0.9). In conclusion, molecules belonging to the series of DDX3 inhibitors were found to be active against both wild type and resistant HIV-1 viral strains, suggesting a new antiviral strategy that could overcome resistance to approved antiretrovirals. These inhibitors represent valuable candidates for the development of molecules with a broad antiviral activity against well-known and emerging viral diseases