Characterization of the EBV-Induced Persistent DNA Damage Response

Area of Science:

• Virology
• Cell Biology
• Cancer Research

Background:

• Epstein-Barr virus (EBV) is a human herpesvirus linked to cancer.
• Early EBV infection of B cells causes proliferation, DNA damage, and senescence.
• The DNA damage response (DDR) pathway is activated during this early stage.

Purpose of the Study:

• Investigate DDR-mediated senescence in early EBV-infected B cells.
• Characterize persistent DNA damage foci.
• Identify regulators of EBV-induced B cell senescence and transformation.

Main Methods:

• Examined DNA damage foci, PML NBs, and telomere dysfunction in arrested EBV-infected B cells.
• Assessed the effect of human telomerase reverse transcriptase (hTERT) upregulation using danazol.
• Investigated sensitivity to Bloom syndrome-associated helicase inhibition in hyper-proliferating EBV-infected cells and LCLs.

Main Results:

• Arrested EBV-infected B cells showed increased PML NBs at DNA damage and telomere sites.
• Telomere dysfunction-induced foci were elevated in these cells.
• Danazol treatment increased hTERT, enabling cells to bypass senescence and enhancing transformation.
• Hyper-proliferating EBV-infected cells were more sensitive to Bloom helicase inhibition than LCLs.

Conclusions:

• Persistent DNA damage foci in early EBV infection are characterized by PML NBs and telomere dysfunction.
• Upregulating hTERT can overcome EBV-induced senescence, promoting cell transformation.
• Bloom helicase is a key regulator of telomere replication and a potential target in early EBV infection.