Effects Of Notch Signaling In L02 Cell Malignant Transformation Induced By Hepatitis B Virus X Protein

Objective: This study aimed to investigate the oncogenic effects of Hepatitis B virus X protein (HBx) and its relationship with Notch signaling in human non-tumour hepatic cell line L02 cells.Methods: The HBx gene was introduced into L02 cells by transfection with vectors stablely expressing HBx. The cell growth, cell cycle, apoptosis and xenograft BALB/c nude mice tumor model of cells were studied. Using Western blot analysis and quantitative real-time RT-PCR, the expression levels of Notch signaling components were also investigated. Blocking Notch signaling with aγ-Secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester(DAPT), the cell growth, cell cycle and apoptosis of cells were analysed again.Results: HBx strongly stimulated cell growth, promoted cell cycle progression and inhibited apoptosis of L02 cells. In addition, HBx accelerated tumor formation of L02 cells in BALB/c nude mice. Upregulated expression of Notch signalig components were observed in stablely HBx-expressing L02 cells. While Notch signaling was blocked by DAPT, the stimulation of cell growth, the promotion of cell cycle progression and the inhibition of apoptosis were partially attenuated in HBx-expressing L02 cells in a dose and time dependent manner. But Normal L02 cells were not significantly affected by Notch signaling blocking.Conclusions: Our studies demonstrate that HBx can significantly promote the growth of human non-tumour hepatic cell line L02 cells both in vitro and in vivo, which may function through the activation of Notch signaling pathway. This will define a novel role of HBx in HCC progression and implicate the Notch signaling as a potential therapeutic target.