AND-Logic-Gated Aptamer Switch for Precise Targeting and Regulation of RNA G-Quadruplexes.

Area of Science:

• Biochemistry and Molecular Biology
• Cancer Research
• Biotechnology

Background:

• RNA G-quadruplexes (rG4s) are crucial in gene regulation and cancer, but their targeted manipulation in tumors is difficult.
• L-RNA aptamers targeting rG4s show high affinity but lack cell-specific delivery for therapeutic use.

Purpose of the Study:

• To engineer an activatable, bispecific aptamer switch (ARGON) for precise targeting and regulation of rG4s in tumor cells.
• To develop a system that utilizes tumor-specific conditions for targeted delivery and activation.

Main Methods:

• Engineered ARGON by integrating an rG4-targeting L-RNA aptamer module with a tumor receptor-targeting DNA aptamer, linked by a glutathione (GSH)-cleavable strand.
• Implemented an AND logic gate requiring both tumor receptor overexpression and elevated GSH for ARGON activation.
• Demonstrated ARGON's ability to bind oncogenic Bcl2 rG4 and target human telomerase RNA component (hTERC) rG4.

Main Results:

• ARGON demonstrated exclusive activation within tumor cells exhibiting both tumor receptor overexpression and elevated GSH levels.
• GSH-triggered cleavage released the L-RNA aptamer, enabling specific binding to oncogenic rG4s like Bcl2.
• The system successfully regulated rG4-associated tumor functions while sparing normal cells, showing broad applicability.

Conclusions:

• The ARGON system provides a novel framework for conditional targeting of nucleic acid structures by combining cell-surface targeting with intracellular sensing.
• This approach enables precise regulation of RNA G-quadruplexes in tumor cells with minimal off-target effects.
• The engineered aptamer switch advances aptamer-based precision biomedicine for cancer therapy.