MAPKs信号通路在肝细胞核因子4α诱导分化治疗肝癌中的重要作用研究

Our previous study has demonstrated that hepatocyte nuclear factors 4α (HNF4α) could induce the differentiation of hepatoma cells—especially cancer stem cells (CSCs) into mature hepatocytes, suppress the activation of Wnt/β-Catenin signaling pathway and reverse the EMT of hepatocellular carcinoma (HCC), and therefore exhibit the striking uppression effect on tumorigenesis and tumor development. Furthermore, HNF4α could regulate the expression level of apoptosis signal-regulating kinase 1(ASK1) transcriptionally and activate the Mitogen activated protein kinases (MAPKs) signaling pathway. At present, some results above have been published in the international journals by the applicant Yin Chuan as the first author or the co-first author, including four SCI articles in which the impact factor of three articles is higher than 10. At the same time, our studies have won the first pize for Shanghai Science and Technology Progress Award. Also, we obtained one domestic invention patent which was successfully authorized. Our preliminary data revealed that upregulation of ASK1 and activation of MAPKs signaling pathway maybe plays a substantial role in the differentiation therapy of HNF4α. In the current study, we will further verify whether HNF4α activates the MAPKs signaling pathway via the enhanced expression of ASK1 and evaluate the importance of ASK1 and MAPKs signaling pathway for HNF4α differentiation therapy. In addition, we will construct the adenoviral vector expressing ASK1, and thereafter investigate the effect of ASK1 on differentiation therapy of HCC in vitro and in vivo and assess the therapeutic efficacy of ASK1 on the different HCC models. These findings might elucidate the novel molecular mechanisms of HNF4α on differentiation therapy of HCC and demonstrate the role of ASK1, and provide a new strategy for clinical therapy of HCC.

在前期研究中发现，肝细胞核因子4α（HNF4α）可以诱导肝癌细胞及肿瘤干细胞分化并抑制Wnt/β-Catenin通路活性及逆转肝癌细胞EMT而有效治疗各种肝癌模型。此外，HNF4α转录调控凋亡信号调节激酶1（ASK1）表达，并活化丝裂原活化蛋白激酶（MAPKs）通路。目前申请人已将部分结果以第一作者在国际杂志上发表，其中SCI收录论著4篇，10分以上3篇，同时相关研究获上海市科技进步奖一等奖，且成功授权国内发明专利一项。在本课题中我们将明确HNF4α是否通过转录调控ASK1表达来活化MAPKs通路及评估ASK1及MAPKs通路在HNF4α分化治疗肝癌中的作用。构建ASK1腺病毒表达载体，并体内外明确ASK1对肝癌诱导分化作用及评估其对不同肝癌模型的治疗效果并探讨其作用机制。本研究将进一步阐明HNF4α诱导分化治疗肝癌的机制及探讨ASK1作为肝癌治疗新靶点的可能性，为肝癌临床治疗提供新思路。

我们的前期研究结果已明确肝细胞核因子4α（hepatocyte nuclear factor 4α，HNF4α）可显著抑制肝癌细胞的生物学特性而有效治疗肝癌。凋亡信号调节激酶1（apoptosis signal-regulating kinase 1，ASK1）参与死亡受体介导的凋亡，可能能抑制肝癌的形成。但ASK1在肝癌进展过程中的表达情况及功能目前尚不明确。本研究明确了HNF4α可直接通过结合ASK1的启动子区而发挥对ASK1表达的调控作用。在人肝癌组织中ASK1的表达被显著抑制，且与HNF4α的表达成正相关。ASK1表达下调与肝癌的恶性临床特征及病人生存期明显相关。此外，我们体外证实上调肝癌细胞中ASK1表达可显著抑制肝癌细胞的生长及侵袭转移等生物学特征。体内实验也证实ASK1可使肝癌细胞在小鼠体内成瘤性完全丧失，且瘤内注射可显著抑制裸鼠皮下肿瘤生长。更有意思的是，通过尾静脉全身注射ASK1可有效抑制肝脏原位种植瘤的生长。我们体外将感染AdHNF4α的Hep3B细胞同时转染siASK1，结果发现，siASK1可有效减弱HNF4α对肝癌细胞的生长抑制作用。综上所述，该研究明确了ASK1对肝癌的抑制作用，以及其在肝癌发展过程中的生物学意义。这些研究结果进一步阐明了ASK1在肝癌中的功能，同时也为临床进展期肝癌提供了新的预后预测靶点以及治疗靶点。 . 该课题按照原定研究计划顺利进行，目前相关研究内容已整理成文，在此研究期间申请者以第一作者或共同第一作者在SCI收录的国际杂志上发表论著2篇（10分以上1篇，5分以上1篇）。同时培养博士研究生一名。