Selective Small-Molecule Targeting of a Triple Helix Encoded by the Long Noncoding RNA, MALAT1

Area of Science:

• Molecular Biology
• Genomics
• Cancer Research

Background:

• Metastasis-associated lung adenocarcinoma transcript 1 (Malat1) is a long noncoding RNA implicated in cancer progression.
• The Malat1 3' terminal stability element for nuclear expression (ENE) is crucial for its nuclear localization and function.
• Targeting Malat1 offers a potential therapeutic strategy for various cancers.

Purpose of the Study:

• To identify small molecules that bind to the Malat1 ENE triplex.
• To investigate the effects of these molecules on Malat1 RNA levels and cancer cell behavior.
• To explore the specificity of these compounds for Malat1.

Main Methods:

• Small molecule microarray screening to identify ENE-binding compounds.
• Mammary tumor organoid models to assess effects on branching morphogenesis.
• Computational modeling, FRET, and NMR spectroscopy to determine binding modes and specificity.

Main Results:

• Multiple chemotypes targeting the Malat1 ENE triplex were identified.
• Compounds 5 and 16 reduced Malat1 RNA levels and affected tumor organoid development.
• Compound 5 demonstrated specificity for Malat1 over Neat1 and viral ENEs, with distinct binding mechanisms.

Conclusions:

• Small molecules targeting the Malat1 ENE triplex can modulate Malat1 function.
• These compounds represent potential therapeutic agents for Malat1-driven cancers.
• Specific targeting of Malat1 ENE provides a foundation for novel anticancer drugs and research tools.