HBx Facilitates Drug Resistance in Hepatocellular Carcinoma via CD133-regulated Self-renewal of Liver Cancer Stem Cells.

Background and aims: Hepatitis B virus (HBV) infection contributes to hepatocellular carcinoma (HCC) tumorigenesis, drug resistance, and recurrence, although the underlying molecular mechanisms remain unclear. Recent studies suggest that HBV infection may be associated with liver cancer stem cells (LCSCs), but the exact mechanisms are yet to be resolved. In this study, we aimed to analyze the role of HBV infection in regulating the stemness of HCCs, which is closely linked to drug resistance.

Methods: Sphere formation assay and real-time Polymerase Chain Reaction quantification were used to isolate and confirm liver cancer stem cells. The inhibitory concentration values of sorafenib and regorafenib were calculated and compared using the Cell Counting Kit-8 assay. HBV infection was used to assess the effect of HBV replication on LCSC markers. Co-immunoprecipitation assay was performed to detect the interaction between CD133 and SRC. Furthermore, we utilized the CRISPR-Cas9 system to knockout CD133 expression in HepG2.2.15 cells.

Results: LCSCs derived from HCCs exhibited high expression of stem cell markers and demonstrated reduced sensitivity to sorafenib and regorafenib. HBV replication promoted both drug resistance and stemness in hepatoma cells and clinical samples. Overexpression of HBx protein in HepG2 cells upregulated the expression of CD133, EpCAM, and CD24, enhancing resistance to sorafenib and regorafenib. Knockout of CD133 expression using the CRISPR-Cas9 system significantly inhibited drug resistance to both sorafenib and regorafenib in HepG2.2.15 cells. Mechanistically, HBV replication promoted CD133 expression, which in turn interacted with the SRC/STAT3 signaling pathway.

Conclusions: Our data suggest that HBV replication enhances the stemness and drug resistance of HCC, providing a strong theoretical foundation for the development of targeted and efficient treatments for HBV-infected HCCs.