Delivery of antisense peptide nucleic acids to cells by conjugation with small arginine-rich cell-penetrating peptide (R/W)9.

Peptide nucleic acids (PNAs) are very attractive antisense and antigene agents, but these molecules are not passively taken into cells. Here, using a functional cell assay and fluorescent-based methods, we investigated cell uptake and antisense activity of a tridecamer PNA that targets the HIV-1 polypurine tract sequence delivered using the arginine-rich (R/W)9 peptide (RRWWRRWRR). At micromolar concentrations, without use of any transfection agents, almost 80% inhibition of the target gene expression was obtained with the conjugate in the presence of the endosomolytic agent chloroquine.

Flavin conjugates for delivery of peptide nucleic acids.

Oligonucleotides and their analogues, such as peptide nucleic acids (PNAs), can be used in chemical strategies to artificially control gene expression. Inefficient cellular uptake and inappropriate cellular localization still remain obstacles in biological applications, however, especially for PNAs. Here we demonstrate that conjugation of PNAs to flavin resulted in efficient internalization into cells through an endocytic pathway.

A steric blocker of translation elongation inhibits IGF-1R expression and cell transformation.

The insulin-like growth factor 1 receptor (IGF-1R) is involved in transformation, survival, mitogenesis and differentiation. It is overexpressed in many tumors and a validated target for anticancer therapy. In cell-free systems, polypyrimidic peptide nucleic acids (PNAs) can form triplex-like structures with messenger RNAs and halt the ribosomal machinery during the translation elongation.

Cellular antisense activity of peptide nucleic acid (PNAs) targeted to HIV-1 polypurine tract (PPT) containing RNA.

DNA and RNA oligomers that contain stretches of guanines can associate to form stable secondary structures including G-quadruplexes. Our study shows that the (UUAAAAGAAAAGGGGGGAU) RNA sequence, from the human immunodeficiency virus type 1 (HIV-1 polypurine tract or PPT sequence) forms in vitro a stable folded structure involving the G-run. We have investigated the ability of pyrimidine peptide nucleic acid (PNA) oligomers targeted to the PPT sequence to invade the folded RNA and exhibit biological activity at the translation level in vitro and in cells.