趋化因子受体CCR7调控上皮间质转化（EMT）促进肝癌耐药的机制研究

The chemokine system plays an important role during the epithelial-mesenchymal transition (EMT) and chemoresistance of tumor cells; however, it has not been clear what is the mechanism.Our preliminary results showed that the expression level of CCR7 was significantly higher in tumor tissue compared with peri-tumor tissue in human hepatocellular carcinaoma(HCC) and it was an independent prognostic factor for overall survival; the bioinformatic analysis also found that proteins downstream of CCR7 signaling were widely involved in EMT, mainly participated in PI3K/Akt pathway and the consequent NF-κB pathway,which is the crosstalking signals of Sorafenib chemoresistence. Therefore, we hypothesized that CCR7 signaling would induce EMT and promote chemoresistance through PI3K/Akt pathway and the consequent NF-κB pathway in HCC. In this study, we will first construct CCR7-knockdown cell lines via CRISPR system and CCR7-over-expression cell lines through lentivirus vector respectively. The CCR7-knockdown and over-expression cell lines will be used to explore the molecular mechanisms underlying CCR7-induced EMT and chemoresistance in HCC. Tissue microarray of HCC will be applied to confirm the correlation between the level of CCR7 and EMT markers, and the relationship between the level of CCR7 and the response to sorafenib treatment after surgical resection. Finally we will perform experiments in vivo in nude mice to further explore whether it is an effective way to enhance the efficacy of sorafenib treatment by blocking CCR7 signaling. We propose this study will not only improve our understading of EMT in HCC but also shed light on the development of new specifical drugs and the treatment of HCC.

最新研究发现趋化因子系统是介导癌细胞发生上皮间质转化（EMT）及耐药的重要因素，但其中的分子机制尚不清楚。我们前期的研究表明，趋化因子受体CCR7表达水平在肝癌组织显著高于配对的癌旁组织，是影响预后的独立危险因素。生物信息学分析及部分实验结果提示，肝癌细胞CCR7受体后的信号通路蛋白与EMT以及化疗药物索拉菲尼作用靶点存在crosstalking信号，以PI3K/Akt及下游的NF-κB信号通路为核心。我们推测肝细胞癌CCR7信号将通过crosstalking旁路激活途径，介导癌细胞发生EMT进而引发耐药。本课题中，我们将用最新技术构建的CRISPR-CCR7敲除、CCR7过表达人肝癌细胞系和临床HCC肝癌组织芯片，在组织、细胞和分子水平探讨CCR7信号介导肝细胞癌EMT及耐药的机制，并通过裸鼠体内实验探讨阻断CCR7信号对索拉菲尼治疗的意义，为肝细胞癌临床诊疗提供新的策略和手段。

CCL21/CCR7信号通路在肿瘤发生发展中有着重要作用。在本项目基金的支持下，我们研究发现CCR7在上皮细胞高表达参与消化系统肿瘤（胃癌、结直肠癌、肝癌）的发展从而影响肿瘤的预后和对靶向药物的耐药性。（1）在胃癌中，CCR7通过诱导发生EMT从而介导胃癌侵袭转移，阻断CCL21/CCR7的信号转导能够抑制肿瘤EMT的发生；（2）在结直肠癌中，CCR7通过PI3K/AKT通路介导西妥昔单抗（Cetuximab）的耐药；（3）在原发性肝癌中，SLC/CCR7信号轴通过介导肿瘤细胞干性而影响HCC对索拉菲尼的耐药；（4）上述作用机制都与肿瘤细胞表面EGFR的表达有关。研究成果分别以通讯作者和第1作者在Discovery Medicine(2015，IF=3.5)、Oncotarget（2015，IF=5.0）、World J Gastroenterol（2016，IF=2.8）、BBRC（2018，IF=3.0）、Journal of Oncology(2018，IF=4.5)等发表SCI论文6篇，研究结果被邀请做大会交流报告1次。还有部分研究成果已经投稿Molecular Cancer（即时IF=9.6,Revised）和Cancer Prevention Discovery（即时IF=4.6, Submitted）。本项目研究成果将为消化系统肿瘤的分子诊断和治疗提供新的治疗策略，为开发广谱的消化系统肿瘤治疗手段和节约社会医疗成本提供了临床转化的可能，将有望在5-10年进行科技成果转化，应用到临床治疗。