Self-Splicing RNA Platform Encodes Twin PROTACs for Dual-E3 Ligase Recruitment and Programmable Protein Degradation

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Proteolysis-targeting chimeras (PROTACs) are effective for targeted protein degradation but face limitations due to synthetic complexity and reliance on single E3 ligases.
• Tumor cells often exhibit low or heterogeneous E3 ligase expression, hindering PROTAC efficacy.

Purpose of the Study:

• To develop a genetically encoded platform for simultaneous recruitment of two distinct E3 ligases using a single transcript.
• To overcome limitations of current PROTAC strategies by enhancing degradation of refractory oncogenic targets.

Main Methods:

• A self-splicing RNA (asRNA) platform was engineered to autonomously generate dual PROTAC effectors from one transcript.
• The asRNA undergoes ribozyme-mediated cleavage to produce peptide-based (VHL ligase) and RNA aptamer-based (Dzip3 ligase) PROTACs.
• The dual-ligase system was tested for degradation of oncogenic targets like c-MYC and EGFR in cancer models.

Main Results:

• The asRNA platform successfully generated dual PROTACs, coordinating the recruitment of VHL and Dzip3 ligases.
• This dual-ligase strategy significantly enhanced the degradation of oncogenic targets c-MYC and EGFR.
• Pronounced antitumor efficacy was observed in cancer models treated with the dual-PROTAC system.

Conclusions:

• The developed genetically encoded asRNA platform enables coordinated dual-E3 ligase recruitment for multivalent protein degradation.
• This innovative approach overcomes limitations of single-E3 ligase PROTACs and expands the range of treatable cancer targets.
• The modular design allows for rapid adaptation without complex chemical synthesis, offering a versatile strategy for targeted cancer therapy.