肝脏前体细胞激活对肝癌患者生存的影响及其在肝癌分子分型中的作用

The microenviorment of liver play an important role in the multi-directional differentiation of hepatic progenitor cells (HPCs), which was recognized as ''the field effect of HPC" that finally determind the subtype and the different stemness characteristics of hepatocellular carcinoma. In our previous study, the proliferation index of dutular reaction (PIDR) was found to correlate with the activation of HPC, and correlate with the expression of some stemness markers in both tumor and nontumor liver, including alpha fetoprotein (AFP), keratin 7 (K7), keratin 19 (K19), epithelial cell adhesion molecule (EpCAM), and c-Kit. Such a high HPC stemness was also found to correlated with tumor multicentric occurrence and patient's poor survival（Hepatology, 2012). The state of HPC activation was therefore used to classify patients with different prognosis. In order to confirm the "field effect" of HPCs, HCC patients with pathological cell-type changes during secondary surgery are enrolled in the study, the state of peritumoral HPC activation, the stem molecular expression peritumoral and intratumor (Bmi1, CK19 and EpCAM, etc.) are analyzed and the relationship between the field effects of HPC and the pathological alterlation of tumor are determinded. Further the functions of Bmi1 in "field effect of HPC" are studied, which include ① The role of Bmi1 in HPC activation and tumor formation in Bmi1 knocked-out mice, ② the coexpresion of Bmi1 and other stemness markers in liver tumor cell lines, ③ the effects of Bmi1 on biological characteristics of liver tumor cells, ④ the interaction between Bmi1 and Hippo-YAP signaling; and ⑤ the MicroRNA regulation of Bmi1. All these studies may provide the better understanding of the molecular classification of HCC and provide new strategies for patients prognosis prediction and therapy intervention.

肝脏前体细胞（Hepatic progenitor cells,HPC）在微环境诱导下可多向分化形成不同特性的肝癌，微环境“场效应”的作用至关重要。我们前期研究发现癌旁胆管反应的增殖状态与HPC激活具有相关性，可影响肿瘤内干性指标的表达，促进肿瘤多中心发生，并影响患者生存。构成了HPC激活的“场效应”（Hepatology）。为深入研究此作用，证实其用于肝癌分子分型的可能，我们以术后复发时病理类型转变的肝癌患者为研究对象，分析患者初次手术时癌旁HPC激活、癌旁及肿瘤内干性分子表达的情况，明确场效应在病理类型转换中的作用。同时对场效应关键分子Bmi1功能进行研究，内容包括：Bmi1对HPC维持和肝癌发生的影响；癌组织及肝癌细胞系中Bmi1与其他干性分子共同激活作用；Bmi1与Hippo-YAP通路的相互作用；及Bmi1的miRNA调节等。为肝癌的分子分型提供依据，并为预后判断提供新的策略。

肝脏前体细胞（Hepatic progenitor cells,HPC）在微环境诱导下可多向分化形成不同特性的肝癌，微环境“场效应”的作用至关重要。我们前期研究发现癌旁胆管反应的增殖状态与HPC激活具有相关性，可影响肿瘤内干性指标的表达，促进肿瘤多中心发生，并影响患者生存。构成了HPC激活的“场效应”（Hepatology）。我们研究发现肝癌细胞内不同干性分子如Bmi1及EpCAM的表达能够增强肝癌细胞的干性特征，干性分子激活越多，干性特征越强。细胞内干性分子表达可使肝癌细胞获得肝前体细胞/胆管细胞样表型，能够表达前体细胞/胆管细胞标记物，可能与肿瘤复发病理亚型转变相关。 高表达的PIDR、癌旁Bmi1及肿瘤MVD是影响混合型肝癌患者术后总体生存的独立危险因素；混合型肝癌患者癌旁Bmi1与PIDR表达水平密切相关；混合型肝癌患者MVD与癌旁Bmi1及PIDR表达水平密切相关。我们发现混合型肝癌患者MVD与癌旁Bmi1及PIDR表达水平相关，癌旁Bmi1与PIDR表达水平显著相关；Bmi1过表达可提升肝前体细胞的增殖及转移能力；Bmi1可促进肝前体细胞的活化，增加胆系标志物CK7、纤维化指标α-SMA及干性标志物CD133及SOX9的表达； Bmi1可促进肝前体细胞血管生成相关细胞因子bFGF、VEGFA、VEGFC的表达。我们的发现为肝癌的分子分型提供依据，并为预后判断提供新的策略。