Antimalarial activities of oligodeoxynucleotide phosphorothioates in chloroquine-resistant Plasmodium falciparum.

Rapaport, Eliezer; Misiura, Konrad; Agrawal, Sudhir; Zamecnik, Paul C.

doi:10.1073/pnas.89.18.8577

Cited by 51 publications

(21 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2B). This value is significantly below those described previously (9,10). This difference may be specific for the PS AS ODN 105 sequence, since the inhibitory efficacy of different ODN sequences clearly varies (Figs.…”

Section: Discussioncontrasting

confidence: 46%

“…Using chloroquine-resistant parasites cultured in vitro, previous experiments in our laboratory showed that AS ODNs were taken up by infected, not uninfected, erythrocytes and that AS ODNs directed against the DHFR gene inhibited parasites in culture (9). However, those studies and others (10) also revealed significant non-DNA sequence-dependent inhibition of parasites when the nuclease-resistant phosphorothioate (PS) form of the ODN was used.…”

mentioning

confidence: 72%

“…Previous work from our laboratory demonstrated that ODNs specifically enter infected, not uninfected, erythrocytes (9). While the mechanism by which this occurs is not understood, it is known that the parasite induces changes in erythrocyte permeability to a variety of solutes (27) and that uptake increases as parasites mature (28 …”

Section: Discussionmentioning

confidence: 99%

“…Previous work in our laboratory (9) and others (10) showed that at high concentrations, PS ODNs inhibit growth of P. falciparum in culture independent of the sequence used. Because of this, Clark and coworkers (10) concluded that virtually all PS ODN inhibition of malaria was due to non-sequence-dependent effects.…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides.

Barker¹,

Metelev²,

Rapaport³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

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 ,LM, phosphorothioate (PS) ODNs inhibited growth in a targetindependent manner. However, between 0.5 and 0.005 ,LM, 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 -0.05 IAM, whereas that for non-sequence-specific controls was 15-fold higher. PS AS ODNs against DNA polymerase ai 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 ,LM, PS AS ODNs targeted against several malarial genes significantly inhibit growth of drugresistant parasites in a nucleotide sequence-dependent manner. This technology represents an alternative method for identifying malarial genes as potential drug targets.

show abstract

Section: Discussioncontrasting

confidence: 46%

mentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides.

Barker¹,

Metelev²,

Rapaport³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The potential of applying nucleic acid therapy to P. falciparum exists owing to differences in the malarial and host genomes as well as several inherent features of the parasite biology (9,10). For example, selective entry by deoxyoligonucleotides into malaria-infected erythrocytes and not into uninfected cells (11) ensures specificity for parasitized cells. In theory, the very (A ϩ T)-rich genome (70% A ϩ T coding regions) of P. falciparum compared with that of human provides a high frequency of sequences that are unique to P. falciparum and are therefore suitable targets for sequencespecific nucleic acids such as antisense oligonucleotides and ribozymes.…”

mentioning

confidence: 99%

Inhibition of Plasmodium falciparum Proliferationin Vitro by Ribozymes

Flores¹,

Atkins²,

Wade³

et al. 1997

Journal of Biological Chemistry

View full text Add to dashboard Cite

Catalytic RNA (ribozymes) suppressed the growth of the human malarial parasite Plasmodium falciparum in vitro. The phosphorothioated hammerhead ribozymes targeted unique regions of the P. falciparum carbamoylphosphate synthetase II gene. The P. falciparum carbamoyl-phosphate synthetase II gene encodes the first and limiting enzyme in the pathway, and its mRNA transcript contains two large insert regions absent in other carbamoyl-phosphate synthetases, including that from humans. These inserts are ideal targets for nucleic acid therapy. Exogenous delivery of ribozymes to cultures reduced malarial viability up to 55% at 0.5 M ribozyme concentrations, which is significantly greater than control levels (5-15% reduction), suggesting a sequence-specific inhibition. This inhibition was shown to be stagespecific, with optimal inhibitions being detected after 24 h, coincident with maximal production of the carbamoyl-phosphate synthetase enzyme in the course of the life cycle of the parasite. A decrease in total carbamoyl-phosphate synthetase activity was observed only in cultures treated with the ribozymes. The task of developing alternative therapeutic agents against malaria is urgent due to the evolution of drug-resistant strains of P. falciparum, the most virulent of all human malarial parasites. Another critical issue to be addressed is the possibility of eliminating or reducing any systemic toxicity to the host, which can potentially be provided by nucleic acid therapy. This work is the first reported assessment of the ability of ribozymes as antimalarials. Ribozyme inhibition assays can also aid in identifying important antimalarial loci for chemotherapy. The malarial parasite can, in turn, be a useful in vivo host to study the catalysis and function of new ribozyme designs.

show abstract

Stereokontrollierte Synthese von Oligonucleosidphosphorothioaten

Stec

Wilk

1994

Angewandte Chemie

View full text Add to dashboard Cite

Bei der Modulation der Genexpression durch Antisense‐Oligonucleotide oder deren Analoga wurden Ergebnisse erzielt, die auf eine neue Generation von Therapeutica gegen virale Infektionen, Krebs und andere Krankheiten hoffen lassen. Oligonucleosidphosphorothioate (Oligo‐S) sind die wirksamsten Analoga bei der Unterdrückung der Biosynthese „ungewollter”︁ Proteine. Erste klinische Untersuchungen von Oligo‐S als Antisense‐Präparate gegen Warzen im Genitalbereich und akute myeloische Leukämie werden zur Zeit durchgeführt; auch gegen Aids sollen Oligo‐S getestet werden. Details des Wirkungsmechanismus, der Aufnahme in die Zelle, des Zelltransports, der subzellulären Lokalisierung und der Wechselwirkung mit zellulären Proteinen sind noch nicht bekannt. A priori wird bei der Applikation angenommen, daß eine rasche und effiziente molekulare Erkennung der Ziel‐RNA durch Oligo‐S erfolgt. Der Einfluß der Chiralität als Eigenschaft des Oligo‐S‐Gesamtmoleküls konnte bislang nicht geklärt werden, da diese Verbindungen nicht stereokontrolliert herstellbar sind. Aufgrund fehlender analytischer Methoden wurde die Diastereomerenzusammensetzung nie bestimmt. Da jedes Diastereomer eine eindeutig definierte stereochemische Einheit ist, stellt sich die Frage, welche Diastereomere die beobachtete biologische Antwort, die positive (heilende) Wirkung und die mögliche negative (toxische) Nebenwirkung, bewirken. Das Ziel dieser Übersicht ist, eine (zum Teil auch spekulative) Abschätzung der Probleme, die mit einer stereokontrollierten Synthese von Oligo‐S verbunden sind, zu liefern sowie den Forschungsstand zu referieren, wobei auch auf Strategien eingegangen werden soll, die zu Oligo‐S mit vorbestimmter Chiralität führen könnten. Dieser Ansatz soll keinesfalls Wissenschaftler von Untersuchungen mit Oligo‐S‐Diastereomerengemischen als Pharmaca abhalten, denn in der medizinischen Chemie wurden viele nützliche Medikamente ohne die genaue Kenntnis der Struktur entwickelt und angewandt. So ist z.B. heute noch die Struktur von Impfstoffen, die Pasteur entdeckte, nicht geklärt.

show abstract

Antimalarial activities of oligodeoxynucleotide phosphorothioates in chloroquine-resistant Plasmodium falciparum.

Cited by 51 publications

References 27 publications

Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides.

Inhibition of Plasmodium falciparum malaria using antisense oligodeoxynucleotides.

Inhibition of Plasmodium falciparum Proliferationin Vitro by Ribozymes

Stereokontrollierte Synthese von Oligonucleosidphosphorothioaten

Contact Info

Product

Resources

About