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Objective To construct a normal immune mouse model carrying hepatitis B virus X (HBx) for long term so as to explore the possible mechanism of HBx causing hepatocellular carcinoma (HCC). Methods Hepatic progenitor cells transfected with HBx were injected into Kunming mice via hepatic portal vein to construct the animal model. The liver tissues were harvested at 30, 90, 180 and 360 d after injection, respectively. The expression of HBx as well as that of Notch1, Notch4 and Hes1 at protein and mRNA levels was detected by Western blotting and RT-qPCR, respectively, and the histopathological changes were observed by HE staining. In addition, a novel γ-secretase inhibitor, DAPT, was intraperitoneally injected at 180 d, and then Western blotting and RT-qPCR were adopted to determine the changes in the expression of apoptosis and cell-cycle-related factors. Results The animal model was successfully constructed, and liver cancer occurred at 360 d. Compared with the control group, the mRNA and protein levels of Notch1, Notch4 and Hes1 were all significantly increased in the HBx group at 30 d (P < 0.05, P < 0.05, P < 0.001), and continued to 360 d (P < 0.05, P < 0.05, P < 0.01); the protein and mRNA levels of Bcl-2, CDK4, CyclinE and CyclinD1 were also up-regulated (protein: P < 0.001, P < 0.01, P < 0.001, P < 0.01; mRNA: P < 0.05, P < 0.001, P < 0.001, P < 0.01), while those of Bax down-regulated in the HBx group (P < 0.001; P < 0.001). However, the inhibitor DAPT significantly reversed the above trends. Conclusion HBx causes anti-apoptosis and abnormal cell cycle changes in mice through persistent activation of the Notch pathway, and then ultimately leads to HCC. |
