In vitro selection and molecular characterization of human immunodeficiency virus type 1 with reduced sensitivity to 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA).
9-[2-(Phosphonomethoxy)ethyl]adenine (PMEA) is an acyclic nucleotide with potent in vitro activity against human immunodeficiency virus type 1 (HIV-1). The present study was undertaken to determine whether HIV-1 resistance to PMEA could be generated by in vitro selection and if so, to determine which mutations in reverse transcriptase (RT) were responsible. HIV-1LAI was serially passaged for 10 months in the presence of increasing concentrations of PMEA up to a maximum of 40 microM. After 40 passages, the 50% inhibitory concentration (IC50) of PMEA had increased almost 7-fold from 4.45 to 30.5 microM. Some cross-resistance to 2',3'-dideoxycytidine (ddC, zalcitabine), 2',3-dideoxyinosine (ddI, didanosine), and 3'-thiacytidine (3TC, lamivudine) was also observed, but no cross-reactive resistance to 3'-azido-3'-thymidine (AZT, zidovudine). Sequencing of the RT encoding region of each of eight pol clones from resistant isolates revealed a Lys-65-->Arg (K65R) substitution. HIV with the K65R mutation inserted by site-directed mutagenesis also had decreased sensitivity to PMEA in H9 cells and a similar cross-resistance profile. Thus, HIV can develop decreased sensitivity to PMEA after long-term in vitro exposure and this change is associated with a K65R substitution. Additional studies will be needed to determine whether a similar mutation in HIV RT develops in patients receiving PMEA or its orally bioavailable prodrug adefovir dipivoxil (bis-POM PMEA).
Foli
A
A
Medicine Branch, National Cancer Institute, Bethesda, MD 20892-1906, USA.
Sogocio
K M
KM
Anderson
B
B
Kavlick
M
M
Saville
M W
MW
Wainberg
M A
MA
Gu
Z
Z
Cherrington
J M
JM
Mitsuya
H
H
Yarchoan
R
R
D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000494:pharmacology*; D002460:Cell Line; D004352:Drug Resistance, Microbial / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D063065:Organophosphonates; D017354:Point Mutation; D012692:Serial Passage
D019380:Anti-HIV Agents; D063065:Organophosphonates; C053001:adefovir; D054303:HIV Reverse Transcriptase; D000225:Adenine