p53 inhibits adeno-associated viral vector integration

Area of Science:

• Molecular Biology
• Genetics
• Virology

Background:

• Adeno-associated viral (AAV) vectors are utilized in gene therapy, with integration efficiency influenced by cellular DNA repair pathways.
• AAV vectors preferentially integrate into DNA repair-deficient cells, such as those with DNA-PKcs deficiency or reduced poly(ADP-ribose) polymerase-1.
• The tumor suppressor protein p53 plays a critical role in regulating DNA repair gene transcription, and its mutation is common in cancers.

Purpose of the Study:

• To investigate the effect of functional p53 on the efficiency of adeno-associated viral (AAV) vector integration.
• To test the hypothesis that p53-negative cells are more permissive to AAV integration than p53-positive cells.

Main Methods:

• Quantification of recombinant AAV vector integration (encoding rep and green fluorescent protein) in HCT116 colon cancer cells.
• Comparison of AAV integration efficiency between p53-expressing (p53-positive) and p53-deficient (p53-negative) cell lines.

Main Results:

• A significantly higher efficiency of AAV integration was observed in p53-negative cells compared to p53-positive cells.
• These findings indicate that functional p53 actively inhibits AAV integration.
• Further experiments suggest p53 binds to the AAV Rep protein, inhibiting its activity during integration.

Conclusions:

• Functional p53 acts as a barrier to adeno-associated viral (AAV) vector genome integration.
• The p53-mediated inhibition of AAV integration is likely due to direct interaction with the AAV Rep protein.
• Understanding this interaction could inform strategies for enhancing AAV vector integration in gene therapy applications.