Engineering the host microenvironment: the “double hit” of HBV subgenotype A1 and G1862T-driven oncogenesis

Introduction Hepatitis B virus (HBV) subgenotype A1 and its endemic G1862T mutation are associated with aggressive, early-onset hepatocellular carcinoma in South Africa. While classically studied via molecular pathways, the biomechanical modifications that prime the hepatic microenvironment for the Epithelial-Mesenchymal Transition (EMT) prior to oncogenesis remain largely unexplored. Methods Using a custom automated bioimaging pipeline and high-resolution confocal microscopy, macroscopic topology, extracellular matrix remodelling, and subcellular compartmentalisation in Huh-7 cells expressing wild-type and G1862T-mutant HBV were quantified. Junctional decoupling and active oncogenic translocation were mapped using ratiometric compartmental analyses. Results The viral backbone engineered a severe mechanical mismatch, inducing a massive bystander-associated upregulation of fibrogenic matrix proteins, F-actin depolymerisation, and significant E-cadherin internalisation. Topological analysis revealed severe, mutation-independent cellular compaction. Although both variants disrupted adherens junctions to a similar extent, the mutant induced an approximately 71% reduction in nuclear β-catenin levels relative to the WT and promoted its perinuclear accumulation, potentially facilitating highly efficient active nuclear translocation. Discussion A mechanobiological “Double Hit” paradigm is proposed. The wild-type HBV backbone (First Hit) acts as an active biomechanical engineer, destroying epithelial mechanoreciprocity to construct a dysplastic, EMT-associated pre-metastatic niche. This foundational structural wreckage creates the optimal, low-resistance environment necessary for the G1862T mutation (Second Hit). By capitalising on both the physical destabilisation and a host-driven proteotoxic stress response, the G1862T HBV efficiently hijacks the surviving β -catenin pool into the nucleus, in a more moderate way than the WT, providing a stealthy, proposed biophysical mechanism for the African enigma.