HIV Protease Inhibitors Possessing a Novel, High-Affinity, and Achiral P1'/P2' Ligand with a Unique Pattern of in Vitro Resistance. Importance of a Conformationally-Restricted Template in the Design of Enzyme Inhibitors

1995 ◽  
Vol 117 (45) ◽  
pp. 11070-11074 ◽  
Author(s):  
J. V. N. Vara Prasad ◽  
Elizabeth A. Lunney ◽  
Donna Ferguson ◽  
Peter J. Tummino ◽  
J. Ronald Rubin ◽  
...  
2005 ◽  
Vol 33 (11) ◽  
pp. 1729-1739 ◽  
Author(s):  
Donglu Zhang ◽  
Theodore J. Chando ◽  
Donald W. Everett ◽  
Christopher J. Patten ◽  
Shangara S. Dehal ◽  
...  

2005 ◽  
Vol 49 (9) ◽  
pp. 3816-3824 ◽  
Author(s):  
S. Weinheimer ◽  
L. Discotto ◽  
J. Friborg ◽  
H. Yang ◽  
R. Colonno

ABSTRACT Substitution of leucine for isoleucine at residue 50 (I50L) of human immunodeficiency virus (HIV) protease is the signature substitution for atazanavir (ATV) resistance. A unique phenotypic profile has been associated with viruses containing the I50L substitution, which produces ATV-specific resistance and increased susceptibility to most other approved HIV protease inhibitors (PIs). The basis for this unique phenotype has not been clearly elucidated. In this report, a direct effect of I50L on the susceptibility to the PI class is described. Cell-based protease assays using wild-type and PI-resistant proteases from laboratory and clinical isolates and in vitro antiviral assays were used to demonstrate a strong concordance between changes in PI susceptibility at the level of protease inhibition and changes in susceptibility observed at the level of virus infection. The results show that the induction of ATV resistance and increased susceptibility to other PIs by the I50L substitution is likely determined at the level of protease inhibition. Moreover, the I50L substitution functions to increase PI susceptibility even in the presence of other primary and secondary PI resistance substitutions. These findings may have implications regarding the optimal sequencing of PI therapies necessary to preserve PI treatment options of patients with ATV-resistant HIV infections.


2007 ◽  
Vol 14 (11) ◽  
pp. 1515-1521 ◽  
Author(s):  
Nurit Hadad ◽  
Rachel Levy ◽  
Francisc Schlaeffer ◽  
Klaris Riesenberg

ABSTRACT Impairment of neutrophil functions and high levels of apoptotic neutrophils have been reported in human immunodeficiency virus (HIV) patients. The aim of the present study was to investigate the direct in vitro effects of the different HIV protease inhibitors (PIs) on neutrophil functions and apoptosis and to explore their mechanisms of action. The effects of nelfinavir (NFV), saquinavir (SQV), lopinavir (LPV), ritonavir (RTV), and amprenavir (APV) in the range of 5 to 100 μg/ml on neutrophil function, apoptosis, and μ-calpain activity were studied. The neutrophil functions studied included superoxide production stimulated by 5 ng/ml phorbol myristate acetate, 5 × 10−7 M N-formyl-methionyl-leucyl-phenylalanine, and 1 mg/ml opsonized zymosan; specific chemotaxis; random migration; and phagocytosis. Apoptosis was determined by DNA fragmentation, fluorescein isothiocyanate-annexin V binding, and nuclear morphology. All three neutrophil functions, as well as apoptosis, were similarly affected by the PIs. SQV and NFV caused marked inhibition and LPV and RTV caused moderate inhibition, while APV had a minor effect. μ-Calpain activity was not affected by the PIs in neutrophil lysate but was inhibited after its translocation to the membranes after cell stimulation. SQV, which was the most potent inhibitor of neutrophil functions and apoptosis, caused significant inhibition of calpain activity, while APV had no effect. The similar patterns of inhibition of neutrophil functions and apoptosis by the PIs, which coincided with inhibition of calpain activity, suggest the involvement of calpain activity in the regulation of these processes.


Author(s):  
B. G. Rao ◽  
C. T. Baker ◽  
J. T. Court ◽  
D. D. Deininger ◽  
J. P. Griffith ◽  
...  

2000 ◽  
Vol 43 (6) ◽  
pp. 1094-1108 ◽  
Author(s):  
Pierre L. Beaulieu ◽  
Paul C. Anderson ◽  
Dale R. Cameron ◽  
Gilbert Croteau ◽  
Vida Gorys ◽  
...  

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