CLIP6-PNA-Peptide Conjugates: Non-Endosomal Delivery of Splice Switching Oligonucleotides

Terese Soudah, Maxim Mogilevsky, Rotem Karni, Eylon Yavin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Efficient delivery of oligonucleotides still remains a challenge in the field of oligonucleotide based therapy. Peptide nucleic acid (PNA), a DNA analogue that is typically synthesized by solid phase peptide chemistry, has been conjugated to a variety of cell penetrating peptides (CPP) as a means of improving its cellular uptake. These CPPs typically deliver their cargoes into cells by an endosomal-dependent mechanism resulting in lower bioavailability of the cargo. Herein, we designed and synthesized PNA-peptide conjugates as splice switching oligonucleotides (SSO) targeting the Mnk2 gene, a therapeutic target in cancer. In humans, the MKNK2 gene, is alternatively spliced, generating isoforms with opposite biological activities: Mnk2a and Mnk2b. It was found that the Mnk2a isoform is down-regulated in breast, lung, brain, and colon tumors and is a tumor suppressor, whereas MnK2b is oncogenic. We have designed and synthesized PNAs that were conjugated to either of the following peptides: A nuclear localization sequence (NLS) or a cytosol localizing internalization peptide (CLIP6). CLIP6-PNA demonstrates effective cellular uptake and exclusively employs a nonendosomal mechanism to cross the cellular membranes of glioblastoma cells (U87). Simple incubation of PNA-peptide conjugates in human glioblastoma cells up-regulates the Mnk2a isoform leading to cancer cell death.

Original languageAmerican English
Pages (from-to)3036-3042
Number of pages7
JournalBioconjugate Chemistry
Issue number12
StatePublished - 20 Dec 2017

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Publisher Copyright:
© 2017 American Chemical Society.


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