Final Report Summary - HIV LTR G-4 (G-quadruplexes in the HIV-1 genome: novel targets for the development of selective antiviral drugs)
HIV-1 is the virus that causes AIDS. But the virus has one weakness: its reliance on G-quadruplexes (G4s) for viral transcription makes it sensitive to drugs specifically targeting G4s.
We found that the only one region of HIV-1 DNA where gene transcription is initiated –its gene promoter – is filled with G4s. This is true even for virus in a latent state which, until now, was completely invisible to immune cells and therapy. We demonstrated how the G4-based centre of HIV transcription regulation is controlled by cellular proteins with an impressively finely tuned network between G4s and cellular proteins. And how different viruses exploit the exact same regulatory mechanism, which is also shared by the eukaryotic cell.
Since each G4 has its own peculiar structure that makes it specifically targetable (similarly to a protein), it means that we have a potential target to eliminate the virus even when it’s in latent state.
By investigating and reporting the structures of the most important HIV G4s at the NMR resolution level, we allowed for the rational design/optimization of drug targeting.
Our team found several different molecules displaying binding to HIV G4s and displaying anti-HIV-1 activity. One family of molecules, selected from an in-house library of compounds, was shown to be effective against HIV-1 in the nanomolar range. The lead of this family was conjugated to peptide nucleic acid (PNA) moieties enabling the delivery of G4-stabilizing compounds to the exact HIV G4 location, a strategy that can be extended to any other G4 of choice. The lead was also modified to be activable upon the desired conditions, such as green light, and to be able to cleave the target, thus producing an irreversible damage to the infected cell.
Another family of molecules was found by screening a commercial library: it targets the most important HIV G4 with a specific and unique type of interaction but poorly binds to cellular G4s and has good antiviral activity. The ultrafast screening method was specifically developed to search for G4-interacting drug-like molecules against any other G4 targets.
Finally, we found that a G4-forming aptamer, AS1411, an anticancer agent previously used in Phase II clinical trials, potently inhibits HIV-1 entry by binding to a viral co-receptor on the cell surface.
Next step is to confirm the anti-HIV activity of the developed molecules in animal models.
Until then, our research has provided a whole new level of understanding of HIV promoter structure and the regulation of viral transcription by G4 structures.
We found that the only one region of HIV-1 DNA where gene transcription is initiated –its gene promoter – is filled with G4s. This is true even for virus in a latent state which, until now, was completely invisible to immune cells and therapy. We demonstrated how the G4-based centre of HIV transcription regulation is controlled by cellular proteins with an impressively finely tuned network between G4s and cellular proteins. And how different viruses exploit the exact same regulatory mechanism, which is also shared by the eukaryotic cell.
Since each G4 has its own peculiar structure that makes it specifically targetable (similarly to a protein), it means that we have a potential target to eliminate the virus even when it’s in latent state.
By investigating and reporting the structures of the most important HIV G4s at the NMR resolution level, we allowed for the rational design/optimization of drug targeting.
Our team found several different molecules displaying binding to HIV G4s and displaying anti-HIV-1 activity. One family of molecules, selected from an in-house library of compounds, was shown to be effective against HIV-1 in the nanomolar range. The lead of this family was conjugated to peptide nucleic acid (PNA) moieties enabling the delivery of G4-stabilizing compounds to the exact HIV G4 location, a strategy that can be extended to any other G4 of choice. The lead was also modified to be activable upon the desired conditions, such as green light, and to be able to cleave the target, thus producing an irreversible damage to the infected cell.
Another family of molecules was found by screening a commercial library: it targets the most important HIV G4 with a specific and unique type of interaction but poorly binds to cellular G4s and has good antiviral activity. The ultrafast screening method was specifically developed to search for G4-interacting drug-like molecules against any other G4 targets.
Finally, we found that a G4-forming aptamer, AS1411, an anticancer agent previously used in Phase II clinical trials, potently inhibits HIV-1 entry by binding to a viral co-receptor on the cell surface.
Next step is to confirm the anti-HIV activity of the developed molecules in animal models.
Until then, our research has provided a whole new level of understanding of HIV promoter structure and the regulation of viral transcription by G4 structures.