HBV基因组整合在肝内胆管细胞癌发生中作用的研究

Intrahepatic cholangiocarcinoma (ICC) is a highly malignant cancer with poor prognosis. Although incident is relatively low, but has experienced continual increase each year. It was thought that HBV infection does not lead to ICC, but recent research has found HBV infection is an important factor for ICC pathogenesis. The mechanism of HBV induced ICC is unclear, but the integration of HBV into the genome is hypothesized to be a crucial step and supported by recent exome research of ICC samples. This research project proposes to use existing exome data as well as whole genome methods, such as HIVID, to specifically capture HBV related sequences and identify HBV integration breakpoints. The effect of HBV integration with respect to gene transcription and translation will be examined using RNA-seq and western blot. The result of this research hopes to provide answers to the mechanism of HBV integration mediated ICC pathogenesis.

尽管肝内胆管细胞癌（intrahepatic cholangiocarcinoma，ICC）发病率较低，但逐年呈上升趋势，由于ICC本身具有高度恶性的生物学行为， ICC患者总体预后极差。既往认为HBV感染不会导致ICC，但近期研究发现HBV感染也是ICC形成重要病因之一。HBV引起ICC机制目前仍不清楚，HBV整合是HBV导致肝细胞癌的重要机制之一，近期研究以及我们前期外显子数据也发现ICC中存在HBV整合，提示HBV整合也可能是ICC发生机制之一。本研究计划先利用现有的ICC外显子数据，寻找、定位HBV整合，后利用HIVID技术在全基因组范围内特异性捕获HBV整合序列，再利用RNA-seq以及Western blot等技术进一步研究HBV整合对一些关键基因转录、翻译的影响。研究结果将为阐明HBV整合在HBV相关性ICC中的发生作用及其可能的机制提供重要的理论依据。

本研究利用收集的103份ICC样本，采用HIVID的全基因组特异性捕获 （HIVID）HBV DNA 测序技术，全面揭示HBV相关性ICC中HBV DNA 整合情况包括整合位点数目、整合位点全基因组范围内的分布、整合位点在重复元件中的分布以及编码区的整合位点事件，进一步对整合基因进行了GO和KEGG功能富集分析。发现3个与HBV DNA基因组整合密切相关的基因，分别为MLL4、GFOD2、FN1。同时，通过RNA-seq检测了ICC 患者的基因表达水平，对HBV DNA整合组与未整合组以及HBV阴性样本进行了差异表达分析，发现了MLL4、GFOD2、FN1基因分别在HBV DNA整合样本中的癌组织的高表达现象。研究结果将为进一步阐明HBV DNA整合在HBV相关性ICC中的发生作用及其可能的机制提供重要的理论依据。