In vitro isolation and identification of human immunodeficiency virus (HIV) variants with reduced sensitivity to C-2 symmetrical inhibitors of HIV type 1 protease.

Abstract

Protease inhibitors are another class of compounds for treatment of human immunodeficiency virus (E1IV)-caused diease. The emergence of resitance to the current antl-HIV drugs makes the determination of potential resistance to protease inhibitors imperative. Here we describe the isolation of an HIV type 1 (HIV-1) resistant to an IHV-protease inhibitor.Serial passage of HIV-1 (strain RF) in the presence of the inhibitor, [2-pyridylacetylisoleucylphenylalanyl-4(CHOH)J2 (P9941), failed to yield a stock of virus with a r t phenotype. However, variants of the virus with 6-to 8-fold reduced sensitivity to P9941 were selcted by using a combination ofplaque assay and endpoint titration. Genetic analysis and computer modeing of the variant proteases revealed a single change in the codon for amino acid 82 (Val -) Ala), which resulted in a protease with lower affinity and reduced sensitivity to this inhibitor and certain, but not all, related inhibitors.

Resistance of human immunodeficiency virus type 1 to protease inhibitors: selection of resistance mutations in the presence and absence of the drug

“…During the initial selection for resistance to ABT-77003 (Kageyama et al, 1992;Kempf et al, 1991Kempf et al, , 1993Kort et al, 1993), viruses gradually and sequentially accumulated up to a total of four specific changes in the protease. These four changes were previously noted for viruses with reduced sensitivity to a number of different HIV-1 protease inhibitors (Condra et al, 1995;Kaplan et al, 1994;Otto et al, 1993;Patick et al, 1995). While the wild-type virus was not passaged in parallel in the absence of the inhibitor as a control, we feel it is extremely unlikely that such mutations resulted from tissue culture adaptation.…”

“…To date, several studies have examined the acquisition of HIV-1 resistance to protease inhibitors and have determined the changes required in the protease to reduce sensitivity to a variety of these compounds (Condra et al, 1995;Danziani et al, 1993;el-Farrash et al, 1994;Ho et al, 1994;Kaplan et al, 1994;Markowitz et al, 1995;Otto et al, 1993 ;Patick et al, 1995 ;Sardana et al, 1994). In vivo and in vitro, HIV-1 resistance to several distinct protease inhibitors is often induced by common amino acid substitutions that can confer various levels of cross-resistance (Condra et al, 1995).…”

“…In spite of the antiviral potency of many recently developed HIV-1 protease inhibitors, the emergence of virus variants with decreased sensitivity to these compounds has been described both in cell culture and in treated patients (Condra et al, 1995;Danziani et al, 1993;el-Farrash et al, 1994;Ho et al, 1994;Kaplan et al, 1994;Markowitz et al, 1995;Otto et al, 1993;Patick et al, 1995). Virus variants that arise from selection by protease inhibitors carry several distinct mutations in the protease coding sequence that appear to emerge sequentially.…”

A preference-based free-energy parameterization of enzyme-inhibitor binding. Applications to HIV-1-protease inhibitor design

“…The property of the HIV-I-PR, and closely related Rous sarcoma virus (RSV) protease, to produce successfully in vivo escape mutants severely limits the usefulness of current protease inhibitors (Grinde et al, 1992a(Grinde et al, , 1992bOtto et al, 1993;Ho et al, 1994). The specificity of the substrate to be processed by the protease enzyme is relatively low, the conserved amino acids are only located in the P,, P, , and Pi sites (Poorman et al, 1991), close to the active site.…”

Solvation effects are responsible for the reduced inhibitor affinity of some HIV‐1 PR mutants

“…Many of these compounds have been found to stop very effectively the replication of the HIV-1 virus in vitro (Wlodawer & Erickson, 1993). However, some of them seem to have limited clinical benefit, due in part to the development of drug resistance, which has been shown to exist in cell cultures (Otto et al, 1993;El-Farrash et al, 1994;Ho et al, 1994;Kaplan et al, 1994;Markowitz et al, 1995), and in clinical isolates from patients (Condra et al, 1995;Winslow et al, 1995). The HIV virus is able to generate drug resistance because of the high mutational frequency in the replication of its genome.…”