UC San Diego

Hepatocellular carcinoma (HCC) claims thousands of lives around the world each year and ranks as one of the most lethal types of cancer. The majority of these cases are caused by Hepatitis B Virus (HBV) infection, with few effective treatments since the underlying mechanisms of how it contributes to cancer remains unclear. Studies on HBV-tumorgenesis link Hepatitis B virus protein X (HBX) to liver oncogenesis initiation. To develop a better understanding of the underlying mechanism, we aim to develop a "humanized" liver mouse model that monitors the progression of HBX-dependent HCC. Previous work in our lab had establish knock-in human embryonic stem (huES) 8 cell lines transfected with a gene construct embedded with the HBX coding sequence through bacterial artificial chromosome (BAC) --- based recombination system. The gene construct expresses HBX once huES 8 cells are differentiated into human hepatocytes. Our modified differentiation protocol successfully generated hepatocytes that expressed specific human hepatic gene markers, such as albumin and AFP, at similar levels to that of HepG2 cells. However, HBX failed to strongly express as a protein. We then tested whether our Anti-F- liver damaged mouse model could reconstitute huES 8- derived hepatocytes within murine livers. Results show that hepatocytes failed to repopulate after Day 15 and Day 28 of intrasplenic-transplantation, but HepG2 control cells were identified in the Day 28 spleen. In conclusion, our differentiation protocol and HBX and transplantation results will benefit in establishing an in vivo HBX- dependent HCC model which can provide valuable knowledge on HBX-based HCC development