Hepatitis B viral DNA integration occurs within three days of infection and is enhanced by ATR inhibition

作者：Dong Li, Jochen M. Wettengel, Harout Ajoyan, Vikki Ho, Guanwei Wu, Sarah Da Won Bae, Henrik Zhang, Delgerbat Boldbaatar, Ulrike Protzer, Jacob George, Mark Douglas, Thomas Tu · 发表于：Tumour Virus Research · 年份：2025 · DOI：10.1016/j.tvr.2025.200332 · 被引用次数：3 · 研究领域：Hepatitis B Virus Studies、DNA Repair Mechanisms、Hepatocellular Carcinoma Treatment and Prognosis

Chronic hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma, with viral DNA integration into the host genome playing a pivotal role in oncogenesis. While HBV integration has been historically considered an event occurring late in a chronic infection, sensitive assays have detected integrations early infection. This study investigates the specific timing and molecular mechanisms of HBV DNA integration using a replication deficient HBV reporter system (HBV-Zeo) in HepG2-NTCP cells. Infection of this virus followed by positive selection led to cellular colony formation, showing that the input virus is the substrate that undergoes integration. By inducing DNA double-strand breaks via X-ray irradiation at specific timepoints after HBV infection, we observed a 2-3-fold increase in integration frequency when cells are irradiated between 16 and 76 h post-infection. Pharmacological inhibition of DNA repair pathways in this specific time window revealed that suppression of homologous recombination (HR) via ATR inhibitors significantly enhances integration rates (2.4-2.8-fold), while microhomology-mediated end joining (MMEJ) inhibition reduced integration to 17 % of untreated controls. These findings suggest that MMEJ plays a key role in HBV DNA integration occurring within hours of HBV infection. Together, our results advance understanding of HBV-associated hepatocarcinogenesis and may inform therapeutic strategies to disrupt viral integration and miti...