Acquired immunodeficiency syndrome (AIDS) is one of the most destructive epidemics in medical history. In 2009, the UNAIDS report estimated that 35 million people are living with human immunodeficiency virus (HIV) infection and AIDS, 25 million deaths have occurred, and 14 million children have been orphaned since the epidemic began in 1981. The discovery of HIV, the etiological agent for AIDS, led to the identification of a number of biochemical targets to combat this devastating disease. Among them, therapeutic inhibition of a proteolytic enzyme, HIV-1 protease, emerged as a critical drug-development target. Subsequent design and discovery of protease inhibitors (PIs) and their introduction into the highly active antiretroviral therapy (HAART), marked the beginning of a new era of management of HIV-1 infection and AIDS. HAART significantly improved the quality of life and life expectancy of patients. There is no cure for HIV/AIDS and long-term treatment has posed a serious challenge because of the emergence of multidrug-resistant HIV-1 variants. About 40-50% of those patients who initially achieved favorable viral suppression to undetectable levels experienced treatment failure. These drug-resistant HIV strains can be transmitted, raising further uncertainty with respect to future treatment options. In addition, PIs are faced with a number of serious limitations including, major toxicity, tolerance, and adherence to complex medical regimens. The development of a new generation of PIs effective against drug-resistant HIV and with minimum side effects, are vital to the future management of HIV/AIDS. Our collaborative research efforts to combat drug resistance, led to the development of darunavir which was first approved for treatment against drug-resistant HIV in June, 2006, and then received full approval for all HIV/AIDS patients including pediatric patients in December, 2008. While darunavir has become a front line therapy against HIV/AIDS, it is far from ideal as an effective long-term treatment option. During this project period, based upon X-ray crystal structures of complexes of darunavir or other PIs with HIV-1 protease, we designed and synthesized a diverse class of potent PIs with marked antiviral activity, and excellent drug-resistance profiles against multidrug-resistant HIV-1 strains. We have also developed tools and important 'backbone binding'design concepts to combat drug-resistance. Furthermore, we have discovered a number of small molecule nonpeptide structural leads for optimization. A recent inhibitor, GRL-0519, has consistently shown a 10-fold improvement of potency compared to darunavir against a panel of multidrug-resistant HIV-1 variants. This PI also exhibited 10-fold better dimerization inhibitory properties of HIV-1 protease. Our current proposed studies are now focused on design, synthesis, and evaluation of the next generation of PIs for clinical development. Our multidisciplinary research efforts integrate structure-based design, synthesis, protein-ligand X-ray crystallography, inhibition kinetics, molecular modeling, and in-depth virus and cell-biological studies.

Public Health Relevance

The 2010 UNAIDS reports 35 million people are living with HIV/AIDS (Acquired Immunodeficiency Syndrome). Progress against this global pandemic requires innovative improved treatment. This proposal details our design and synthesis of next generation protease inhibitors to address critical problems of existing therapy.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Method to Extend Research in Time (MERIT) Award (R37)
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Special Emphasis Panel (ZRG1-AARR-C (02))
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Fabian, Miles
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Purdue University
Schools of Arts and Sciences
West Lafayette
United States
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Amano, Masayuki; Salcedo-Gómez, Pedro Miguel; Zhao, Rui et al. (2016) A Modified P1 Moiety Enhances In Vitro Antiviral Activity against Various Multidrug-Resistant HIV-1 Variants and In Vitro Central Nervous System Penetration Properties of a Novel Nonpeptidic Protease Inhibitor, GRL-10413. Antimicrob Agents Chemother 60:7046-7059
Aoki, Manabu; Hayashi, Hironori; Yedidi, Ravikiran S et al. (2016) C-5-Modified Tetrahydropyrano-Tetrahydofuran-Derived Protease Inhibitors (PIs) Exert Potent Inhibition of the Replication of HIV-1 Variants Highly Resistant to Various PIs, including Darunavir. J Virol 90:2180-94
Ghosh, Arun K; Brindisi, Margherita (2015) Organic carbamates in drug design and medicinal chemistry. J Med Chem 58:2895-940
Ghosh, Arun K; Yu, Xufen; Osswald, Heather L et al. (2015) Structure-based design of potent HIV-1 protease inhibitors with modified P1-biphenyl ligands: synthesis, biological evaluation, and enzyme-inhibitor X-ray structural studies. J Med Chem 58:5334-43
Ghosh, Arun K; Xu, Chun-Xiao; Osswald, Heather L (2015) Enantioselective Synthesis of Dioxatriquinane Structural Motifs for HIV-1 Protease Inhibitors Using a Cascade Radical Cyclization. Tetrahedron Lett 56:3314-3317
Ghosh, Arun K; Takayama, Jun; Kassekert, Luke A et al. (2015) Structure-based design, synthesis, X-ray studies, and biological evaluation of novel HIV-1 protease inhibitors containing isophthalamide-derived P2-ligands. Bioorg Med Chem Lett 25:4903-9
Ghosh, Arun K; Yashchuk, Sofiya; Mizuno, Akira et al. (2015) Design of gem-difluoro-bis-tetrahydrofuran as P2 ligand for HIV-1 protease inhibitors to improve brain penetration: synthesis, X-ray studies, and biological evaluation. ChemMedChem 10:107-15
Agniswamy, Johnson; Louis, John M; Shen, Chen-Hsiang et al. (2015) Substituted Bis-THF Protease Inhibitors with Improved Potency against Highly Resistant Mature HIV-1 Protease PR20. J Med Chem 58:5088-95
Amano, Masayuki; Tojo, Yasushi; Salcedo-Gómez, Pedro Miguel et al. (2015) A novel tricyclic ligand-containing nonpeptidic HIV-1 protease inhibitor, GRL-0739, effectively inhibits the replication of multidrug-resistant HIV-1 variants and has a desirable central nervous system penetration property in vitro. Antimicrob Agents Chemother 59:2625-35
Ghosh, Arun K; Martyr, Cuthbert D; Kassekert, Luke A et al. (2015) Design, synthesis, biological evaluation and X-ray structural studies of HIV-1 protease inhibitors containing substituted fused-tetrahydropyranyl tetrahydrofuran as P2-ligands. Org Biomol Chem 13:11607-21

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