title: Effects of the W153L substitution in HIV reverse transcriptase on viral replication and drug resistance to multiple categories of reverse transcriptase inhibitors.
abstract: A W153L substitution in HIV-1 reverse transcriptase (RT) was recently identified by selection with a novel nucleotide-competing RT inhibitor (NcRTI) termed compound A that is a member of the benzo[4,5]furo[3,2,d]pyrimidin-2-one NcRTI family of drugs. To investigate the impact of W153L, alone or in combination with the clinically relevant RT resistance substitutions K65R (change of Lys to Arg at position 65), M184I, K101E, K103N, E138K, and Y181C, on HIV-1 phenotypic susceptibility, viral replication, and RT enzymatic function, we generated recombinant RT enzymes and viruses containing each of these substitutions or various combinations of them. We found that W153L-containing viruses were impaired in viral replicative capacity and were hypersusceptible to tenofovir (TFV) while retaining susceptibility to most nonnucleoside RT inhibitors. The nucleoside 3TC retained potency against W153L-containing viruses but not when the M184I substitution was also present. W153L was also able to reverse the effects of the K65R substitution on resistance to TFV, and K65R conferred hypersusceptibility to compound A. Biochemical assays demonstrated that W153L alone or in combination with K65R, M184I, K101E, K103N, E138K, and Y181C impaired enzyme processivity and polymerization efficiency but did not diminish RNase H activity, providing mechanistic insights into the low replicative fitness associated with these substitutions. We show that the mechanism of the TFV hypersusceptibility conferred by W153L is mainly due to increased efficiency of TFV-diphosphate incorporation. These results demonstrate that compound A and/or derivatives thereof have the potential to be important antiretroviral agents that may be combined with tenofovir to achieve synergistic results.
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Xu
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Colby-Germinario
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Maureen
authors.initials: M
authors.lastname: Oliveira
authors.affiliation: Department of Biological Sciences, Boehringer Ingelheim (Canada) Ltd., Laval, Quebec, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rajotte
authors.affiliation: Department of Biological Sciences, Boehringer Ingelheim (Canada) Ltd., Laval, Quebec, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Bethell
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada Department of Medicine, McGill University, Montreal, Quebec, Canada Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada mark.wainberg@mcgill.ca.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000480:Alkynes; D019943:Amino Acid Substitution; D019380:Anti-HIV Agents / Q000494:pharmacology*; D048588:Benzoxazines / Q000494:pharmacology; D003521:Cyclopropanes; D024882:Drug Resistance, Viral / Q000235:genetics*; D057809:HEK293 Cells; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D019259:Lamivudine / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019829:Nevirapine / Q000494:pharmacology; D063065:Organophosphonates / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D000068698:Tenofovir; D014779:Virus Replication
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D063065:Organophosphonates; D011743:Pyrimidines; D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D019829:Nevirapine; D000068698:Tenofovir; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D000225:Adenine; C098320:efavirenz