Peptide Nucleic Acid conjugates are delivered in cell with bubbles and ultrasound to regulate gene expression
The RNAG4 (Microbubble-mediated transfection of peptide nucleic acid conjugates targeting mRNA quadruplexes to modulate gene expression in vivo) project has designed highly specific peptide nucleic acid (PNA)-based conjugates to interact with RNA secondary structures. With a fluorescence-based electrophoretic mobility shift assay, the team demonstrated that all the developed ligands could bind RNA with high affinity and specificity. The RNAG4 team identified new quadruplex targets in genes that are of clinical interest. In particular, they looked at genes coding for N-Ras, Aurora kinase A and Aurora kinase C. Mutations in these genes are linked to several human cancer cell types. Future planned research includes to see if engineered small molecules can prevent Aurora Kinase A expression. One limitation of PNAs is that they don't readily pass across cell membranes. To overcome this, the researchers used microbubbles and ultrasound (sonoporation). Results from fluorescence microscopy showed instances of more than 45 % increased transfection efficiency on using ultrasound and virtually no transfection otherwise. RNAG4 project work on optimising sonoporation conditions to maximise localised transfection of therapeutic PNA conjugates has great clinical potential. The lab is continuing to optimise both the microbubbles and the ultrasound pulse sequences.
