Hexon-specific PEGylated adenovirus vectors utilizing avidin-biotin interaction

Area of Science:

• Biotechnology
• Gene Therapy
• Virology

Background:

• Polyethylene glycol (PEG) modification of adenovirus (Ad) vectors improves systemic administration by evading antibodies and prolonging circulation.
• Conventional PEGylation non-specifically attaches PEG to Ad capsid proteins, significantly reducing transduction activity by hindering receptor binding (coxsackievirus-adenovirus receptor - CAR).

Purpose of the Study:

• To develop a method for PEGylating Ad vectors without compromising transduction efficiency.
• To improve Ad vector pharmacokinetics and biodistribution for potential gene therapy applications.

Main Methods:

• Engineered an Ad vector by inserting a biotin-binding peptide (BAP) into hexon hypervariable region 5 (HVR5).
• Achieved specific PEGylation via avidin-biotin interaction between the BAP-modified hexon and PEG.
• Evaluated transduction efficiency in vitro and in vivo biodistribution and transduction after intravenous administration.

Main Results:

• Hexon-specific PEGylation did not significantly reduce Ad vector transduction efficiency in vitro.
• The modified Ad vector (Ad-BAP/Bio/Avi/Bio-PEG-L2) exhibited prolonged blood retention and reduced liver transduction after intravenous administration.
• While accumulating in tumors, Ad-BAP/Bio/Avi/Bio-PEG-L2 showed minimal transduction within the tumor tissue.

Conclusions:

• Hexon-specific PEGylation is a viable strategy to improve Ad vector pharmacokinetics without substantial loss of transduction.
• Further optimization is needed to enhance tumor-specific transduction for effective gene delivery to tumors.