Development of Antiviral Therapy of HIV-1 Infection

Division Of Clinical Sciences - Nci

Investigators

Linked publications, trials & patents

Abstract

In the period to cover the present Annual Report, we designed and synthesized a series of potent HIV-1 protease inhibitors exploiting substituted tetrahydrofuran derivatives were that served as the P2 ligand. Both enantiomers of the tetrahydrofuran derivatives were synthesized in optically active forms using lipase-PS catalyzed enzymatic resolution as the key step. These tetrahydrofuran derivatives are designed to promote hydrogen bonding and van der Waals interactions with the backbone atoms in the S2 subsite of the HIV-1 protease active site. Several inhibitors displayed very potent HIV-1 protease inhibitory activity. A high-resolution X-ray crystal structure of an inhibitor-bound HIV-1 protease provided important insight into the ligand binding site interactions in the active site. Notably, we generated a high-level four-class-resistant HIV-1 variant (HIVKGD) in vitro and evaluated the susceptibility of HIVKGD to all the four classes' FDA-approved drugs. Unexpectedly, we found that most PIs examined had potent activity against HIVKGD. In particular, GRL-142, a primarily protease-inhibiting agent, exerted extremely potent activity against HIVKGD. HIVKGD was found extremely susceptible to a previously reported HIV-1 protease inhibitor, GRL-142, with IC50 of 130 femtomolar. When cells were infected with HIVKGD's IN-gene-containing recombinant-HIV in the presence of GRL-142, significant decrease of unintegrated 2-LTR-circular cDNA was observed, suggesting that nuclear import of PIC was severely compromised by GRL-142. The data on 2-LTR-circular cDNA production and crystallographic features of GRL-142 complexed with IN showed that GRL-142 binds to IN's NLS and blocks the transport of PIC into the nucleus. The present study should shed light on the development of NLS-targeting antiretroviral therapeutics and the design of inhibitors of other NLS-carrying viruses. The data should offer a new modality to block HIV-1 infectivity and replication and shed light on developing NLS inhibitors for AIDS therapy. We also conducted the synthesis and biological evaluation of darunavir-derived HIV-1 protease inhibitors and their functional effect on enzyme inhibition and antiviral activity. The P2' 4-amino functionality was modified to make a number of amide derivatives to interact with residues in the S2' subsite of the HIV-1 protease active site. Several compounds exhibited picomolar enzyme inhibitory and low nanomolar antiviral activity. The X-ray crystal structure of the chloroacetate derivative bound to HIV-1 protease was determined. Interestingly, the active chloroacetate group converted to the acetate functionality during X-ray exposure. The structure revealed that the P2' carboxamide functionality makes enhanced hydrogen bonding interactions with the backbone atoms in the S2'-subsite. Using the Maestro suite of programs from Schrodinger, we also carried out molecular dynamics simulations of HIV-protease and HIV-integrase systems to understand the mechanisms of drug resistance.