Poster abstracts
Poster number 131 submitted by Krishna Shivakumar
Locked Nucleic Acid Oligonucleotides Facilitate RNA•LNA-RNA Triple Helix Formation and Reduce MALAT1 Levels
Krishna M Shivakumar (Department of Chemistry and Biochemistry, University of Notre Dame), Gowthami Mahendran (Department of Chemistry and Biochemistry, University of Notre Dame), Jessica A Brown (Department of Chemistry and Biochemistry, University of Notre Dame)
Abstract:
Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and multiple endocrine neoplasia-β (MENβ) are two long noncoding RNAs upregulated in multiple cancers, marking these RNAs as therapeutic targets. While traditional small molecule and antisense-based approaches are effective, we report a locked nucleic acid (LNA)-based approach that targets the MALAT1 and MENβ triple helices, structures comprised of a U-rich stem-loop and an A-rich tract. Two LNA oligonucleotides resembling the A-rich tract (i.e. A9GCA4) were examined: an LNA (L15) and a phosphorothioate LNA (PS-L15). L15 binds tighter than PS-L15 to the MALAT1 and MENβ stem loops, although both L15 and PS-L15 enable RNA•LNA-RNA triple helix formation. Based on UV thermal denaturation assays, both LNAs selectively stabilize the Hoogsteen interface by 5-13 degree Celsius more than the Watson-Crick interface. Furthermore, we show that L15 and PS-L15 displace the A-rich tract from the MALAT1 and MENβ stem loop and methyltransferase-like protein 16 (METTL16) from the METTL16-MALAT1 triple helix complex. HCT116 cells transfected with LNAs have 2-fold less of MALAT1 and MENβ. This LNA-based approach represents a potential therapeutic strategy for the dual targeting of MALAT1 and MENβ.
Keywords: MALAT1 triple helix, MEN triple helix, LNA