Mechanistic Studies and Modeling Reveal the Origin of Differential Inhibition of Gag Polymorphic Viruses by HIV-1 Maturation Inhibitors

PLoS Pathogens

Zeyu Lin¹  Mark Cockett¹  Mark Krystal¹  Ira B. Dicker¹  Beata Nowicka-Sans¹  Tricia Protack¹  Tian Yuan²  Hong Yang²  Nicholas A. Meanwell³  Zheng Liu³  Alicia Regueiro-Ren³  Max Lataillade⁴  Joseph Cantone⁵  Hao Lu⁵  Dieter Drexler⁵ 

[1] Departments of Virology, Bristol-Myers Squibb Research & Development, Wallingford, Connecticut, United States of America;Discovery Chemistry Platforms, Princeton, New Jersey, United States of America;Discovery Chemistry, Bristol-Myers Squibb Research & Development, Wallingford, Connecticut, United States of America;Global Clinical Development, Bristol-Myers Squibb Research & Development, Wallingford, Connecticut, United States of America;Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Research & Development, Wallingford, Connecticut, United States of America

关键词: HIV-1;    Proteases;    Serine proteases;    HIV;    Chemical dissociation;    293T cells;    Crystal structure;    Luciferase;   

DOI  :  10.1371/journal.ppat.1005990

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

HIV-1 maturation inhibitors (MIs) disrupt the final step in the HIV-1 protease-mediated cleavage of the Gag polyprotein between capsid p24 capsid (CA) and spacer peptide 1 (SP1), leading to the production of infectious virus. BMS-955176 is a second generation MI with improved antiviral activity toward polymorphic Gag variants compared to a first generation MI bevirimat (BVM). The underlying mechanistic reasons for the differences in polymorphic coverage were studied using antiviral assays, an LC/MS assay that quantitatively characterizes CA/SP1 cleavage kinetics of virus like particles (VLPs) and a radiolabel binding assay to determine VLP/MI affinities and dissociation kinetics. Antiviral assay data indicates that BVM does not achieve 100% inhibition of certain polymorphs, even at saturating concentrations. This results in the breakthrough of infectious virus (partial antagonism) regardless of BVM concentration. Reduced maximal percent inhibition (MPI) values for BVM correlated with elevated EC50 values, while rates of HIV-1 protease cleavage at CA/SP1 correlated inversely with the ability of BVM to inhibit HIV-1 Gag polymorphic viruses: genotypes with more rapid CA/SP1 cleavage kinetics were less sensitive to BVM. In vitro inhibition of wild type VLP CA/SP1 cleavage by BVM was not maintained at longer cleavage times. BMS-955176 exhibited greatly improved MPI against polymorphic Gag viruses, binds to Gag polymorphs with higher affinity/longer dissociation half-lives and exhibits greater time-independent inhibition of CA/SP1 cleavage compared to BVM. Virological (MPI) and biochemical (CA/SP1 cleavage rates, MI-specific Gag affinities) data were used to create an integrated semi-quantitative model that quantifies CA/SP1 cleavage rates as a function of both MI and Gag polymorph. The model outputs are in accord with in vitro antiviral observations and correlate with observed in vivo MI efficacies. Overall, these findings may be useful to further understand antiviral profiles and clinical responses of MIs at a basic level, potentially facilitating further improvements to MI potency and coverage.

【 授权许可】

CC BY