ZIA SC 006738 (ZIA) | |||
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Title | Development of Antiviral Therapy of HIV-1 Infection | ||
Institution | NCI, Bethesda, MD | ||
Principal Investigator | Mitsuya, Hiroaki | NCI Program Director | N/A |
Cancer Activity | N/A | Division | CCR |
Funded Amount | $488,693 | Project Dates | null - null |
Fiscal Year | 2018 | Project Type | Intramural |
Research Topics w/ Percent Relevance | Cancer Types w/ Percent Relevance | ||
Cancer (100.0%) | N/A | ||
Research Type | |||
Chemoprevention Systemic Therapies - Discovery and Development |
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Abstract | |||
Since our first report of darunavir (DRV) in 2003, we continued optimization based on the structure of DRV, seeking novel protease inhibitors (PIs) that are more potent against a variety of existing multi-PI-resistant HIV-1 variants with greater safety, do not permit or substantially delay the emergence of HIV-1 variants resistant to the very PIs, and favorably penetrate into the CNS, and identified GRL-142. GRL-142 contains newly generated pharmacophores such as an unprecedented 6-5-5 ring-fused crown-like tetrahydropyranofuran as the P2-ligand (Crn-THF), P1-bis-fluoro-benzyl (bis-Fbz), and P2'-cyclopropyl-amino-benzothiazole (Cp-Abt). We examined the activity of five PIs including GRL-121 and -142 against seven resistant HIV-1 variants, which we had previously selected in vitro with each of the seven FDA-approved PIs (invitroHIVPIRs). Most of the seven variants were significantly less susceptible to two PIs, lopinavir (LPV) and ATV, that have presently been relatively well used in clinics. DRV also failed to effectively block most of the seven variants with IC50 value fold-differences ranging from 2- to 86-fold. However, GRL-121 showed extremely potent activity against all the seven variants examined, presenting IC50 values ranging 0.0018 to 0.13 nM. The activity of GRL-121 against all the seven variants was significantly more potent than that against cHIVNL4-3WT. Surprisingly, GRL-142 showed even more potent activity against the seven variants with IC50 values of 0.0000019 nM (1.9 fM) to 0.015 nM. The activity of GRL-142 against the variants was also significantly more potent than that against cHIVNL4-3WT. We, furthermore, examined the activity of the five PIs against six recombinant infectious clinical HIV-1 variants (rCLHIVs) that are highly resistant to all the currently available PIs including DRV. GRL-121 exerted highly potent activity with IC50 values of 0.028 to 12 nM, while GRL-142 again showed even more potent activity with IC50 values of 0.0052 to 0.69 nM. Moreover, we carried out assays of DRV, GRL-121, and GRL-142 against 18 recombinant HIV-1 variants carrying a single amino acid substitution known to be associated to HIV-1 resistance to various PIs. DRV was effective against all the recombinant clones with IC50 values of 0.29 to 4.7 nM. GRL-121 was again found to be highly potent against all the variants examined with IC50 values of 0.015 to 350 pM. GRL-142 was even more potent against the variants as compared to GRL-121. It is noted that GRL-142 was extremely potent against three recombinant HIV-1 variants (cHIVNL4-3V32I, cHIVNL4-3G48V, and cHIVNL4-3I50V) with IC50 values of 12, 36, and 93 attomolar (aM), respectively. We determined the structural interactions of GRL-142 with wild-type HIV-1 protease (PRWT) using X-ray crystallography. GRL-142 binds in the active site of PRWT in two distinct conformations (related by 180-degrees rotation) with relative occupancies of 0.53 and 0.47. The structural description is derived from the interactions of the major conformation of GRL-142 with PRWT. GRL-142 has a Crn-THF as the P2-ligand moiety and a Cp-Abt as the P2' ligand moiety. Both groups make critical interactions with amino acids spanning distinct regions of PRWT active site. The Crn-THF moiety has two oxygen atoms and they both form hydrogen bonding interactions with the backbone amides of D29 and D30. The thiazole nitrogen makes a hydrogen bond interaction with the backbone NH of D30'. The P2' amino group forms polar interactions with the sidechain carboxylate of D30'. The carbonyl and sulfonyl oxygens have polar interactions with the PR flap residues I50 and I50' through a bridging water molecule. The transition state mimic hydroxyl group forms polar interactions with the catalytic aspartates D25 and D25'. There is another hydrogen bond interaction from the amide nitrogen of the carbamate moiety to the backbone carbonyl oxygen of G27. Many of these polar interactions with HIV protease are also seen in DRV compl |