Podoplanin阳性表达的癌相关成纤维细胞在肝内胆管癌淋巴管新生中的作用和机制研究

Intrahepatic cholangiocarcinoma is a highly malignant hepatic neoplasm, the incidence of which ranks second only after hepatocellular carcinoma in liver malignant tumors. Cancer associated lymphangiogenesis is one of the most important factors leading to early metastasis and unfavorable prognosis. Cancer associated fibroblasts (CAFs), as a group of activated mesenchymal cells, play important roles in regulating tumor development and lymphangiogenesis. Our previous results showed that Podoplanin positive CAFs were closely correlated with lymphangiogenesis. Besides, Podoplanin positive CAFs were confirmed to transfer into neolymphtaic vessels through “mesenchymal to lymphatic endothelial transition”. Furthermore, we found that miRNA and mTOR signaling may regulate the “mesenchymal to lymphatic endothelial transition”. Therefore, we hypothesized that miRNA from intrahepatic cholangiocarcinoma may regulate the expression of mTOR/VEGF-C signaling to form neolymphatic vessels through “mesenchymal to lymphatic endothelial transition” of Podoplanin positive CAFs, which eventually promotes tumor metastasis and progression. We plan to identify the function and specific molecular mechanism of Podoplanin positive CAFs in lymphangiogenesis both in vitro and in vivo. These findings may develop novel strategies for inhibiting lymphangiogenesis of intrahepatic cholangiocarcinoma.

肝内胆管癌是发病率仅次于肝细胞癌的原发肝脏肿瘤，淋巴管新生是导致肝内胆管癌淋巴结转移和预后不佳的重要因素；与此同时，肝内胆管癌中丰富的癌相关成纤维细胞（CAFs）在肿瘤进展和淋巴管新生中起重要调控作用。我们前期研究结果表明肝内胆管癌中Podoplanin阳性表达的CAFs和淋巴管新生呈正相关，同时发现了该亚群CAFs可在肿瘤微环境下发生“间质-淋巴内皮转化”形成新生淋巴管，进一步我们筛选发现miRNA与mTOR/VEGF-C信号通路在其中起重要调控作用。由此我们推测：来源于肝内胆管癌的候选miRNA可能通过调控mTOR/VEGF-C信号通路的表达促进Podoplanin阳性CAFs发生“间质-淋巴内皮转化”从而形成新生淋巴管。本课题拟对Podoplanin阳性表达的CAFs在淋巴管新生中的作用以及具体分子机制进行研究，从而为肝内胆管癌淋巴管新生的机制和防治研究开拓新思路。

肝内胆管癌是发病率仅次于肝细胞癌的原发肝脏肿瘤，淋巴管新生是导致肝内胆管癌淋巴结转移和预后不佳的重要因素；与此同时，肝内胆管癌中丰富的癌相关成纤维细胞（CAFs）在肿瘤进展和淋巴管新生中起重要调控作用。本课题拟探索并验证肝内胆管癌中Podoplanin阳性表达的CAFs可在肿瘤微环境下通过“间质-淋巴内皮转化”形成新生淋巴管，并进一步研究调控该通路的具体分子机制，从而为肝内胆管癌淋巴管新生的机制和防治研究开拓新思路。.本项目首先明确Podoplanin阳性表达的CAFs是肝内胆管癌患者预后不良的独立危险因素，同时该亚群CAFs与新生淋巴管密度成正相关，说明其可能促进淋巴管新生；在细胞实验中我们发现Podoplanin阳性CAFs可在肿瘤微环境中形成管腔样结构，不同时间点检测显示CAFs标志物α-SMA表达逐渐下降，而淋巴内皮细胞标志物VEGFR-3、LYVE-1则相应上升，血管内皮标志物无明显改变，从而在体外实验中说明Podoplanin阳性CAFs可发生“间质-淋巴内皮转化”形成新生淋巴管；进一步我们进行高通量测序，发现mTOR信号通路多个基因表达可以调控“间质-淋巴内皮转化”，通过抑制mTOR信号通路基因和VEGF-C表达后发现，细胞成管显著下降，同时CAFs标志物表达上升，淋巴管标志物表达下降；最后，我们在动物实验中验证了Podoplanin阳性CAFs及mTOR/VEGF-C信号通路在肝内胆管癌中通过“间质-淋巴内皮转化”参与淋巴管新生。.以上研究结果明确肝内胆管癌中Podoplanin阳性CAFs可通过“间质-淋巴内皮转化”形成新生淋巴管，为淋巴管新生的新机制提供理论依据，同时以上结果为抑制肝内胆管癌淋巴管新生寻找到了有价值的治疗新靶点，从而为降低患者肿瘤复发、改善患者预后提供了新思路。