title: Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides.
abstract: We studied inhibition of growth of the malaria parasite Plasmodium falciparum in in vitro culture using antisense (AS) oligodeoxynucleotides (ODNs) against different target genes. W2 and W2mef strains of drug-resistant parasites were exposed to AS ODNs over 48 hr, and growth was determined by microscopic examination and [3H]hypoxanthine incorporation. At ODN concentrations of 1 microM, phosphorothioate (PS) ODNs inhibited growth in a target-independent manner. However, between 0.5 and 0.005 microM, ODNs against dihydrofolate reductase, dihydropteroate synthetase, ribonucleotide reductase, the schizont multigene family, and erythrocyte binding antigen EBA175 significantly inhibited growth compared with a PS AS ODN against human immunodeficiency virus, two AS ODNs containing eight mismatches, or the sense strand controls (P < 0.0001). The IC50 was approximately 0.05 microM, whereas that for non-sequence-specific controls was 15-fold higher. PS AS ODNs against DNA polymerase alpha showed less activity than that for other targets, whereas a single AS ODN against triose-phosphate isomerase did not differ significantly from controls. We conclude that at concentrations below 0.5 microM, PS AS ODNs targeted against several malarial genes significantly inhibit growth of drug-resistant parasites in a nucleotide sequence-dependent manner. This technology represents an alternative method for identifying malarial genes as potential drug targets.
authors.affiliation: Hybridon, Inc., Worcester, MA 01605, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Barker
authors.forename: V
authors.initials: V
authors.lastname: Metelev
authors.forename: E
authors.initials: E
authors.lastname: Rapaport
authors.forename: P
authors.initials: P
authors.lastname: Zamecnik
mesh_terms: D000818:Animals; D001483:Base Sequence; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D017125:Genes, Protozoan; D016778:Malaria, Falciparum / Q000628:therapy; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000201:enzymology / Q000254:growth & development*; D015800:Protozoan Proteins / Q000235:genetics; D012264:Ribonucleotide Reductases / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics; D014305:Triose-Phosphate Isomerase / Q000235:genetics
chemical_list: D016376:Oligonucleotides, Antisense; D015800:Protozoan Proteins; D012264:Ribonucleotide Reductases; D013762:Tetrahydrofolate Dehydrogenase; D004259:DNA-Directed DNA Polymerase; D014305:Triose-Phosphate Isomerase