Inhibition of gene expression in Entamoeba histolytica with antisense peptide nucleic acid oligomers

Peptide nucleic acids (PNAs) may be a potent tool for gene function studies in medically important parasitic organisms, especially those that have not before been accessible to molecular genetic knockout approaches. One such organism is Entamoeba histolytica, the causative agent of amebiasis, which infects about 500 million people and is the cause of clinical disease in ov er 40 million each year, mainly in the tropical and subtropical world. We u sed PNA antisense oligomers to inhibit expression of an episomally expresse d gene (neomycin phosphorotransferase, NPT) and a chromosomal gene (EhErd2, a homolog of Erd2, a marker of the Golgi system in eukaryotic cells) in ax enically cultured trophozoites of E. histolytica. Measurement of NPT enzyme activity and EhErd2 protein levels, as well as measurement of cellular pro liferation, revealed specific decreases in expression of the target genes, and concomitant inhibition of cell growth, in trophozoites treated with mic romolar concentrations of unmodified antisense PNA oligomers.