Promoter-Targeting RNA Technologies: An Epigenetic Strategy for Gene Activation and Gene Silencing

Area of Science:

• Molecular Biology
• Epigenetics
• RNA Therapeutics

Background:

• Promoter-targeted RNAs (PTRs) represent a new class of therapeutics that directly modulate gene expression at the transcriptional level.
• Unlike post-transcriptional RNA methods, PTRs target gene promoter regions for activation or suppression, influencing chromatin and epigenetic regulation.
• This approach offers stable, long-lasting gene control and reversible genomic reprogramming without permanent DNA alterations, distinguishing them from CRISPR-based methods.

Purpose of the Study:

• To review the diverse modalities of promoter-targeted RNAs (PTRs) and their therapeutic applications.
• To explore the potential of PTRs in reactivating tumor suppressor genes and downregulating oncogenes.
• To highlight the clinical translation of PTRs and identify challenges for future development.

Main Methods:

• Review of preclinical and clinical studies on various PTR modalities, including small activating RNAs (saRNAs), small interfering RNAs (siRNAs), promoter-targeted R-loop inducers, peptide nucleic acids, RNA aptamers, and triplex-forming RNAs.
• Analysis of PTR mechanisms involving chromatin accessibility and histone modification.
• Evaluation of clinical trial data for PTR-based cancer therapies.

Main Results:

• Preclinical studies demonstrate PTRs' efficacy in reactivating silenced tumor suppressor genes and downregulating oncogenes.
• saRNAs like MTL-CEBPA and RAG-01 have advanced to Phase I/II clinical trials for liver and bladder cancer.
• PTRs offer targeted and reversible control of gene expression.

Conclusions:

• PTRs show significant therapeutic potential for cancer and other diseases due to their precise transcriptional control.
• Efficient nuclear delivery, mitigation of off-target effects, and management of immune responses are critical for clinical success.
• Further research focusing on chemical modifications, delivery systems, and tissue-specific targeting is essential for advancing PTR therapeutics.