Inhibition of human immunodeficiency virus type 1 reverse transcriptase by the 5'-triphosphate beta enantiomers of cytidine analogs.
(-)-beta-L-2',3'-Dideoxycytidine (L-ddC) and (-)-beta-L-2',3'-dideoxy-5-fluorocytidine (L-FddC) have been reported to be potent and selective inhibitors of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in vitro. In the present study, the 5'-triphosphates of L-ddC (L-ddCTP) and L-FddC (L-FddCTP) were demonstrated to competitively inhibit HIV-1 reverse transcriptase (RT), with inhibition constants (KiS) of 2 and 1.6 microM, respectively, when a poly(rI).oligo(dC)10-15 template primer was used; in comparison Ki values for beta-D-2',3'-dideoxycytidine 5'-triphosphate (D-ddCTP) and beta-D-2',3'-dideoxy-5-fluorocytidine 5'-triphosphate (D-FddCTP) were 1.1 and 1.4 microM, respectively. Use of the mutant RT at position 184 (substitution of methionine to valine [M184V]), which is associated with resistance to beta-L-2',3'-dideoxy-3'-thiacytidine (3TC) and beta-L-2',3'-dideoxy-5-fluoro-3'-thiacytidine (FTC), resulted in significant increases (50- to 60-fold) in Ki values for L-ddCTP and L-FddCTP, whereas the elevation in Ki values for D-ddCTP and D-FddCTP was moderate (2-fold). L-ddCTP and L-FddCTP did not inhibit human DNA polymerases alpha and beta up to 100 microM. In contrast, D-ddCTP and D-FddCTP inhibited human DNA polymerase beta, with Ki values of 0.5 and 2.5 microM, respectively. By using sequencing analysis, L-ddCTP and L-FddCTP exhibited DNA chain-terminating activities toward the parental HIV-1 RT, whereas they were not a substrate for the mutant M184V HIV-1 RT.L-ddC and L-FddC did not inhibit the mitochondrial DNA content of human cells up to a concentration of 10 microM, whereas D-ddC and D-FddC decreased the mitochondrial DNA content by 90% at concentrations of 1 and 10 microM, respectively. All of these results suggest that further development of L-ddC, and L-FddC in particular, is warranted as a possible anti-HIV candidate.
Faraj
A
A
Department of Pharmacology, University of Alabama at Birmingham 35294.
Agrofoglio
L A
LA
Wakefield
J K
JK
McPherson
S
S
Morrow
C D
CD
Gosselin
G
G
Mathe
C
C
Imbach
J L
JL
Schinazi
R F
RF
Sommadossi
J P
JP
D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors; D004272:DNA, Mitochondrial / Q000032:analysis; D003845:Deoxycytosine Nucleotides / Q000494:pharmacology*; D054306:Dideoxynucleotides; D054303:HIV Reverse Transcriptase; D008969:Molecular Sequence Data; D018894:Reverse Transcriptase Inhibitors; D013237:Stereoisomerism; D016047:Zalcitabine / Q000031:analogs & derivatives* / Q000494:pharmacology
D000998:Antiviral Agents; D004272:DNA, Mitochondrial; D003845:Deoxycytosine Nucleotides; D054306:Dideoxynucleotides; D018894:Reverse Transcriptase Inhibitors; C091740:2',3'-dideoxy-5-fluorocytidine 5'-triphosphate; C037406:2',3'-dideoxycytidine 5'-triphosphate; D016047:Zalcitabine; D004247:DNA; D054303:HIV Reverse Transcriptase; D004256:DNA Polymerase I