Bimax1和siRNA抑制内输蛋白α/β转运pre-S/S截短体入核致小鼠肝癌

350 millions chronic hepatitis B (CHB)were reported in the world, and the near 25% CHB are develeped into hepatoma in the last.Long-term depression of HBV results in the drug fast mutation and induces hepatoma.The rtA181T mutation of anti-lamivudine can generate pre-S/S decurtation, which leads to hepatoma due to its transfer to nucleus for trans-activation of c-Myc.The rtA181T brings about the mouse hepatoma by injecting into vein.The macromo binding with importin α/β is a very important pathway entering into nucleus.The anti-cancer drugs targeting importin α/βcan chock the important pathway of the mutated HBV resulting in hepatoma.Accordingly, our study is intented to investigate the action of importin αinhibited by Bimax1 and importin β depressed by siRNA on the pre-S/S decurtation entry into nucleus in vitro.Furthermore, these actions are confirmed by the mouse hepatoma model resulted from rtA181T.So, our study can offer the references to exploring the prevention and treating of hepatoma resulting from the drug fast mutations,which posses very important theoretical values and real senses.

全球有约3.5亿慢性乙型肝炎，其中近25%最终发展为肝癌。长期抑制HBV导致耐药突变，突变诱发肝癌。耐拉米夫定的rtA181T突变产生截短的pre-S/S，入核反式激活c-Myc致肝癌。将rtA181T片段注射裸鼠体内可致肝癌。生物大分子与内输蛋白α/β识别结合是其入核的重要途径。以此靶点设计的抗HBV突变致癌药，阻滞了HBV突变致肝癌的重要途径。故本研究拟Bimax1特异抑制内输蛋白α，siRNA特异抑制内输蛋白β，细胞水平观察其对pre-S/S截短体的入核转运，rtA181T小鼠肝癌模型验证其抑癌作用，为探索防治HBV突变致癌的研究，提供理论和实验参考，具有十分重要的理论价值和现实意义。

1.项目背景. 2010版《慢性乙肝防治指南》强调“最大限度地长期抑制HBV，以延缓和减少肝脏失代偿、肝硬化及肝细胞癌”，但长期治疗将导致HBV耐药突变。目前，研究发现一些突变可明显增加肝细胞癌风险，而且难以预防。rtA181T是一种常见的多药耐药突变，可被拉米夫定和阿德福韦酯选择并蓄积于患者体内，而其编码的表面抗原截短体可诱导裸鼠发生肝细胞癌，但有关其致癌机制罕见报道。原癌基因激活是肿瘤发生的重要机制，HBV表面抗原截短体若要入细胞核直接激活原癌基因则需核转运蛋白参与。我们拟研究rtA181T突变型HBsAg与核转运蛋白KPNA2结合，然后转运入细胞核上调c-Myc表达诱导肝细胞癌。.2.主要研究内容. ①野生型及rtA181T突变型HBsAg与核转运蛋白KPNA2的细胞内结合实验；. ②野生型及rtA181T突变型HBsAg的细胞核转运；. ③rtA181T突变型HBsAg上调c-Myc表达；. ④野生型HBsAg及伊维菌素对KPNA2的抑制作用；. ⑤rtA181T突变型HBsAg对LO2细胞中KPNA2启动子去甲基化作用；. ⑥小鼠肝细胞癌变模型验证野生型HBsAg及伊维菌素的抗癌作用。.3.重要结果. ① 野生型及rtA181T突变型HBsAg可与核转运蛋白KPNA2结合，但仅rtA181T突变型HBsAg被转运入核；. ②野生型HBsAg和伊维菌素均可下调rtA181T突变型HBsAg诱导的c-Myc表达；. ③rtA181T突变型HBsAg可使LO2细胞中的KPNA2启动子去甲基化。.4.科学意义. ① 对长期使用核苷类药物治疗慢性乙型肝炎提出了严正质疑；. ②为HBV突变致肝细胞癌的预防探索了一条有价值的参考途径。