Discovery of Novel Integrase Inhibitors Acting outside the Active Site Through High-Throughput Screening

Abstract

Currently, an increasing number of drugs are becoming available to clinics for the treatment of HIV infection. Even if this targeted therapy is highly effective at suppressing viral replication, caregivers are facing growing therapeutic failures in patients, due to resistance with or without treatment adherence concerns. Accordingly, it is important to continue to discover small molecules that have a novel mechanism of inhibition. In this work, HIV integrase inhibitors were selected by high-throughput screening. Chemical structure comparisons enabled the identification of stilbene disulfonic acids as a potential new chemotype. Biochemical characterization of the lead compound stilbenavir (NSC34931) and a few derivatives was performed. Stilbene disulfonic acid derivatives exhibit low to sub-micromolar antiviral activity, and they inhibit integrase through DNA-binding inhibition. They probably bind to the C-terminal domain of integrase, in the cavity normally occupied by the noncleaved strand of the viral DNA substrate. Because of this original mode of action compared to active site strand transfer inhibitors, they do not exhibit cross-resistance to the three main resistance pathways to integrase inhibitors (G140S-Q148H, N155H, and Y143R). Further structure–activity optimization should enable the development of more active and less toxic derivatives with potential clinical relevance.

Natural and nature-inspired stilbenoids as antiviral agents

“…In a more recent study, other stilbene disulfonic acids resulted to inhibit IN by a novel mechanism [77] (Fig. 13).…”

“…Notably, preliminary in vivo studies reported in the literature have shown that in general, stilbenoids show low bioavailability and undergo extensive metabolism and it has been pointed out that bioconverted forms of polyphenols, (phase I and II metabolism) may probably have more importance than the parent compound found in the diet or administered in therapy. In many cases, synthetic efforts produced stilbene derivatives with greater potency than their parent compounds, allowing to expand knowledge on modes of action and to deepen structure-activity relationship studies of the most active compounds [39,70,76,77,82,91].…”

“…The two compounds were tested against clinically relevant mutants resistant to conventional IN inhibitors and the stilbene derivatives maintain their activity at sub-micromolar concentration, representing a potential therapeutic alternative. Indeed, they were found to compete with DNA in binding IN, especially involving the C-terminal domain (CTD), at concentrations 10 times lower than that necessary to inhibit 3 0 P and ST [77].…”

“…This wide class of viruses is responsible for several illnesses, such as hand-foot-and-mouth (HFM) disease, encephalitis, paralysis, respiratory diseases, poliomyelitis, affecting millions of people Table 4 Summary of stilbene disulfonic acid derivatives activities from Ref. [77].…”

Quinolinonyl Non-Diketo Acid Derivatives as Inhibitors of HIV-1 Ribonuclease H and Polymerase Functions of Reverse Transcriptase

“…His-tagged NL4-3 IN was expressed from a pET15b plasmid in the E. coli BL21 pLys strain. Recombinant protein was purified as previously described 67 following a batch preparation on Ni-NTA beads (Qiagen, Paris, France).…”