scholarly journals In Vitro Effect of α1‐Acid Glycoprotein on the Anti‐Human Immunodeficiency Virus (HIV) Activity of the Protease Inhibitor CGP 61755: A Comparative Study with Other Relevant HIV Protease Inhibitors

1997 ◽  
Vol 175 (5) ◽  
pp. 1063-1070 ◽  
Author(s):  
Janis K. Lazdins ◽  
Jürgen Mestan ◽  
Gerard Goutte ◽  
Maja R. Walker ◽  
Guido Bold ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Comparative Study ◽  
Protease Inhibitor ◽  
Protease Inhibitors ◽  
Hiv Protease ◽  
Hiv Protease Inhibitors ◽  
Acid Glycoprotein ◽  
Immunodeficiency Virus ◽  
Vitro Effect

scholarly journals Atazanavir Signature I50L Resistance Substitution Accounts for Unique Phenotype of Increased Susceptibility to Other Protease Inhibitors in a Variety of Human Immunodeficiency Virus Type 1 Genetic Backbones

2005 ◽  
Vol 49 (9) ◽  
pp. 3816-3824 ◽  
Author(s):  
S. Weinheimer ◽  
L. Discotto ◽  
J. Friborg ◽  
H. Yang ◽  
R. Colonno
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protease Inhibitors ◽  
Treatment Options ◽  
Hiv Infections ◽  
Hiv Protease ◽  
Hiv Protease Inhibitors ◽  
Protease Inhibition ◽  
Immunodeficiency Virus ◽  
Increased Susceptibility

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.

scholarly journals Direct Effect of Human Immunodeficiency Virus Protease Inhibitors on Neutrophil Function and Apoptosis via Calpain Inhibition

2007 ◽  
Vol 14 (11) ◽  
pp. 1515-1521 ◽  
Author(s):  
Nurit Hadad ◽  
Rachel Levy ◽  
Francisc Schlaeffer ◽  
Klaris Riesenberg
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protease Inhibitors ◽  
Neutrophil Function ◽  
Significant Inhibition ◽  
Hiv Protease ◽  
Minor Effect ◽  
Hiv Protease Inhibitors ◽  
Calpain Activity ◽  
Immunodeficiency Virus

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.

scholarly journals Antiviral activity of the dihydropyrone PNU-140690, a new nonpeptidic human immunodeficiency virus protease inhibitor.

1997 ◽  
Vol 41 (5) ◽  
pp. 1058-1063 ◽  
Author(s):  
S M Poppe ◽  
D E Slade ◽  
K T Chong ◽  
R R Hinshaw ◽  
P J Pagano ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Protease Inhibitors ◽  
Hiv Protease ◽  
Pharmacokinetic Studies ◽  
Hiv Protease Inhibitors ◽  
Highly Active ◽  
Immunodeficiency Virus ◽  
Hiv 1

PNU-140690 is a member of a new class of nonpeptidic human immunodeficiency virus (HIV) protease inhibitors (sulfonamide-containing 5,6-dihydro-4-hydroxy-2-pyrones) discovered by structure-based design. PNU-140690 has excellent potency against a variety of HIV type 1 (HIV-1) laboratory strains and clinical isolates, including those resistant to the reverse transcriptase inhibitors zidovudine or delavirdine. When combined with either zidovudine or delavirdine, PNU-140690 contributes to synergistic antiviral activity. PNU-140690 is also highly active against HIV-1 variants resistant to peptidomimetic protease inhibitors, underscoring the structural distinctions between PNU-140690 and substrate analog protease inhibitors. PNU-140690 retains good antiviral activity in vitro in the presence of human plasma proteins, and preclinical pharmacokinetic studies revealed good oral bioavailability. Accordingly, PNU-140690 is a candidate for clinical evaluation.

scholarly journals Evaluation of reverse transcriptase and protease inhibitors in two-drug combinations against human immunodeficiency virus replication.

1996 ◽  
Vol 40 (6) ◽  
pp. 1346-1351 ◽  
Author(s):  
C A Deminie ◽  
C M Bechtold ◽  
D Stock ◽  
M Alam ◽  
F Djang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Combination Therapy ◽  
Protease Inhibitor ◽  
Reverse Transcriptase ◽  
Protease Inhibitors ◽  
Nucleoside Analogs ◽  
Drug Combinations ◽  
Hiv Protease ◽  
Human Immunodeficiency Virus Replication ◽  
Immunodeficiency Virus

Current treatments for human immunodeficiency virus (HIV) include both reverse transcriptase and protease inhibitors. Results from in vitro and clinical studies suggest that combination therapy can be more effective than single drugs in reducing viral burden. To evaluate compounds for combination therapy, stavudine (d4T), didanosine (ddI), or BMS-186,318, an HIV protease inhibitor, were combined with other clinically relevant compounds and tested in a T-cell line (CEM-SS) that was infected with HIV-RF or in peripheral blood mononuclear cells infected with a clinical HIV isolate. The combined drug effects were analyzed by the methods described by Chou and Talalay (Adv. Enzyme Regul. 22:27-55, 1984) as well as by Prichard et al. (Antimicrob. Agents Chemother. 37:540-545, 1993). The results showed that combining two nucleoside analogs (d4T-ddI, d4T-zidovudine [AZT], and d4T-zalcitabine [ddC]), two HIV protease inhibitors (BMS-186,318-saquinavir, BMS-186,318-SC-52151, and BMS-186,318-MK-639) or a reverse transcriptase and a protease inhibitor (BMS-186,318-d4T, BMS-186,318-ddI, BMS-186,318-AZT, d4T-saquinavir, d4T-MK-639, and ddI-MK-639) yielded additive to synergistic antiviral effects. In general, analysis of data by either method gave consistent results. In addition, combined antiviral treatments involving nucleoside analogs gave slightly different outcomes in the two cell types, presumably because of a difference in phosphorylation patterns. Importantly, no strong antagonism was observed with the drug combinations studied. These data should provide useful information for the design of clinical trials of combined chemotherapy.

scholarly journals ABT-378, a Highly Potent Inhibitor of the Human Immunodeficiency Virus Protease

1998 ◽  
Vol 42 (12) ◽  
pp. 3218-3224 ◽  
Author(s):  
Hing L. Sham ◽  
Dale J. Kempf ◽  
Akhteruzammen Molla ◽  
Kennan C. Marsh ◽  
Gondi N. Kumar ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protease Inhibitor ◽  
Response To Therapy ◽  
Hiv Protease ◽  
Healthy Human ◽  
Human Volunteers ◽  
Immunodeficiency Virus ◽  
Potent Protease Inhibitor

ABSTRACT The valine at position 82 (Val 82) in the active site of the human immunodeficiency virus (HIV) protease mutates in response to therapy with the protease inhibitor ritonavir. By using the X-ray crystal structure of the complex of HIV protease and ritonavir, the potent protease inhibitor ABT-378, which has a diminished interaction with Val 82, was designed. ABT-378 potently inhibited wild-type and mutant HIV protease (Ki = 1.3 to 3.6 pM), blocked the replication of laboratory and clinical strains of HIV type 1 (50% effective concentration [EC50], 0.006 to 0.017 μM), and maintained high potency against mutant HIV selected by ritonavir in vivo (EC50, ≤0.06 μM). The metabolism of ABT-378 was strongly inhibited by ritonavir in vitro. Consequently, following concomitant oral administration of ABT-378 and ritonavir, the concentrations of ABT-378 in rat, dog, and monkey plasma exceeded the in vitro antiviral EC50 in the presence of human serum by >50-fold after 8 h. In healthy human volunteers, coadministration of a single 400-mg dose of ABT-378 with 50 mg of ritonavir enhanced the area under the concentration curve of ABT-378 in plasma by 77-fold over that observed after dosing with ABT-378 alone, and mean concentrations of ABT-378 exceeded the EC50 for >24 h. These results demonstrate the potential utility of ABT-378 as a therapeutic intervention against AIDS.

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