Beta Human Papillomavirus 8E6 Attenuates Non-Homologous End Joining by Hindering DNA-PKcs Activity

Area of Science:

• Molecular biology
• Virology
• Oncology

Background:

• Cutaneous viral infections often occur with environmental genotoxin exposure, like UV radiation.
• DNA repair is crucial for preventing tumorigenesis; impaired repair is a cancer driver.
• Beta-human papillomaviruses (β-HPVs) are known to affect DNA repair signaling, but their role in skin cancer is debated.

Purpose of the Study:

• To investigate the role of β-HPV 8 E6 protein in DNA double-strand break (DSB) repair pathways.
• To determine if β-HPV 8 E6 impacts non-homologous end joining (NHEJ), another DSB repair mechanism.

Main Methods:

• Characterization of β-HPV 8 E6 protein's interaction with DNA repair factors.
• Assessing the impact of β-HPV 8 E6 on homologous recombination and non-homologous end joining (NHEJ) pathways.
• Investigating the role of p300 and DNA-dependent protein kinase (DNA-PK) in β-HPV 8 E6-mediated DNA repair inhibition.

Main Results:

• β-HPV 8 E6 was previously shown to impair homologous recombination by destabilizing the p300 transcription factor.
• This study demonstrates that β-HPV 8 E6 also inhibits the NHEJ pathway, a critical DSB repair mechanism.
• β-HPV 8 E6 attenuates DNA-dependent protein kinase (DNA-PK) activity, essential for NHEJ.
• The inhibition of NHEJ by β-HPV 8 E6 occurs through both p300-dependent and independent mechanisms.

Conclusions:

• β-HPV 8 E6 possesses broader genome destabilizing capabilities than previously understood.
• The impairment of multiple DNA repair pathways by β-HPV 8 E6 may contribute to its role in human disease, including potentially promoting tumorigenesis.