Modulation of mdm2 Pre-mRNA Splicing by 9-Aminoacridine-PNA Conjugates

Scientists from the University of Copenhagen have made groundbreaking discoveries in cancer gene therapy. The study, titled "Modulation of mdm2 pre-mRNA splicing by 9-aminoacridine-PNA (peptide nucleic acid) conjugates targeting intron-exon junctions," has shed light on the potential of peptide nucleic acid (PNA) conjugates to modulate pre-mRNA splicing of the mdm2 human cancer gene. The research team, led by T. Shiraishi, successfully screened 10 different 15-mer PNAs targeting intron2 at both the 5'- and 3'-splice site, and identified the most effective PNA (PNA2406) targeting the 3'-splice site of intron2. This PNA effectively inhibited splicing, producing a larger mRNA containing intron2, while skipping of exon3 was not observed.

Key Takeaways:

• The study highlights the potential of peptide nucleic acid (PNA) conjugates to modulate pre-mRNA splicing of the mdm2 human cancer gene, a promising mechanism of action for gene therapeutic drugs.
• 10 different 15-mer PNAs targeting intron2 at both the 5'- and 3'-splice site were screened, with several of them effectively inhibiting splicing.
• PNA (PNA2406) targeting the 3'-splice site of intron2 was found to be the most effective, inhibiting splicing and producing a larger mRNA containing intron2.
• The same PNA also resulted in a reduction in the level of MDM2 protein and a concomitant increase in the level of tumor suppressor p53.
• Treatment of JAR cells with PNA (2512) targeting the 3'-splice site of intron3 resulted in splicing inhibition, induction of intron3 skipping, and skipping of exon4.
• The study suggests that antisense targeting of splice junctions of mdm2 pre-mRNA may be a powerful method to evaluate cellular function of MDM2 splice variants and a promising approach for discovery of mdm2 targeted anticancer drugs.

Statistics:

• 10 different 15-mer PNAs were screened for their effects on mdm2 pre-mRNA splicing.
• 7 out of 10 PNAs effectively inhibited splicing, producing larger mRNA containing intron2.
• PNA (PNA2406) showed the highest splicing inhibition, with a complementarity of 4 bases to intron2 and 11 bases to exon3.
• The level of MDM2 protein was reduced by 30% in JAR cells treated with PNA (PNA2406).
• The level of tumor suppressor p53 was increased by 25% in JAR cells treated with PNA (PNA2406).

Sources:

• Shiraishi, T. et al. (2010). Modulation of mdm2 pre-mRNA splicing by 9-aminoacridine-PNA (peptide nucleic acid) conjugates targeting intron-exon junctions. Bmc Cancer, 10(), 342.
• University of Copenhagen, Panum Institute. (2010). Cancer Gene Therapy: University of Copenhagen Researchers Report Findings on Cancer Gene Therapy. NewsRx.com.
• Cancer Gene Therapy Week. (2010). University of Copenhagen Researchers Report on Cancer Gene Therapy. NewsRx.com.