Effect of small molecule eRF3 degraders on premature termination codon readthrough

Area of Science:

• Molecular Biology
• Genetics
• Pharmacology

Background:

• Premature termination codon (PTC) readthrough is a therapeutic strategy for genetic diseases caused by nonsense mutations.
• Aminoglycosides induce PTC readthrough but cause significant toxicity.
• Developing compounds to enhance PTC readthrough or reduce aminoglycoside toxicity is crucial.

Purpose of the Study:

• To identify compounds that enhance aminoglycoside-induced PTC readthrough.
• To investigate the role of eukaryotic release factors (eRFs) in PTC readthrough and nonsense-mediated mRNA decay (NMD).
• To evaluate the therapeutic potential of novel compounds in patient-derived cells.

Main Methods:

• Utilized small interfering RNAs (siRNAs) targeting eRF3a and eRF3b.
• Tested cereblon E3 ligase modulators (CC-885, CC-90009) for their effect on eRF3 degradation and PTC readthrough.
• Assessed NMD pathway modulation and compound toxicity in patient-derived cell lines with specific nonsense mutations.

Main Results:

• siRNAs against eRF3a/eRF3b and modulators CC-885/CC-90009 enhanced G418-induced PTC readthrough by degrading eRF3.
• eRF3 degradation suppressed NMD and selectively stabilized nonsense-mutated transcripts.
• CC-90009 demonstrated lower toxicity than CC-885 and enhanced PTC readthrough with aminoglycosides in multiple disease models.

Conclusions:

• Degradation of eRF3a/eRF3b enhances PTC readthrough and suppresses NMD.
• CC-90009 is a promising candidate for PTC readthrough therapy due to its efficacy and reduced toxicity.
• Combination therapy with CC-90009 and aminoglycosides (e.g., gentamicin, ELX-02) holds potential for treating genetic diseases caused by nonsense mutations.