淋巴细胞特异性转录因子Aiolos在肺癌远端转移中的功能研究

Epigenetic dysregulation and consequent activation and/or silencing of tumor related genes are now believed to play critical roles during all stages of tumorigenesis. Previously, our experimental data from lung cancer cells showed that ectopic expression of a lymphocyte lineage-restricted transcription factor, Aiolos, forces their acquisition of certain hematopoietic characteristics, facilitates their escape from primary tumors and subsequent survival following anchorage deprivation and consequently promotes metastasis. The related paper has been in press in Cancer Cell, 2014. In the analysis of gene expression microarray data, we found a chemokine receptor, CXCR4, was upregulated dramatically by Aiolos ectopic expression. Its ligand, CXCL12, is concentrated in bone marrow, liver and lymph node. These data suggested that Aiolos may play a critical role in the distant metastasis of lung cancer cell targeting bone, liver and lymph node. The objective of this proposal is to investigate the function of Aiolos through CXCR4 in lung cancer distant metastasis using multiple techniques including immunohistochemistry and single cell RT-PCR in clinical tumor tissues and nude mice, and to find the molecular mechanism and function of the transcriptional activation of CXCR4 by Aiolos using 3C and biochemical assay. The findings of this proposal may help to pave the new way for treatment of lung cancer metastasis.

表观遗传调控紊乱所致的基因异常开启和/或关闭在肿瘤发生发展中起着至关重要的作用。我们前期工作发现淋巴细胞特异性转录因子Aiolos在肺癌细胞中异位表达，赋予肺癌细胞一些类似淋巴细胞的特性，促进肿瘤转移，相关工作已被Cancer Cell接受。在分析Aiolos异位表达引起的基因表达谱变化时，发现Aiolos可以显著上调趋化因子受体CXCR4的表达，而其配体CXCL12在骨髓、肝、淋巴结等浓度较高，提示Aiolos可能在肺癌细胞靶向骨、肝等器官及淋巴结的远端转移过程中发挥着重要作用。基于此，本项目拟通过免疫组化、单细胞RT-PCR和动物实验研究临床肿瘤标本和生物体内Aiolos表达与肺癌远端转移的相关性，通过细胞学实验研究Aiolos-CXCR4的作用机理，并以3C技术为主细致研究Aiolos转录激活CXCR4的表观遗传机制，最终揭示Aiolos在肺癌远端转移中的作用，为肺癌治疗提供新方案。

本项目拟研究淋巴细胞特异性转录因子Aiolos通过特异性上调趋化因子受体CXCR4 的表达，从而影响肺癌细胞在靶向骨、肝等器官及淋巴结的器官特异性远端转移过程中的作用和调控机制。经过四年的研究，我们顺利完成了预期目标，取得结果如下：①检测了临床标本中Aiolos、CXCR4的表达与肿瘤远端转移的相关性研究，发现肿瘤标本中Aiolos与CXCR4的表达严格正相关，并与肿瘤患者的预后严格负相关；②通过裸鼠心内注射模型实验发现Aiolos的确能够通过促进促进肿瘤远端转移的发生，且这个过程与CXCR4密切相关；③通过细胞生物学实验发现Aiolos能够通过CXCR4显著促进肿瘤细胞的趋化运动、以及迁移、浸润能力；④Aiolos直接结合在CXCR4基因的enhancer上，通过enhancer-promoter之间的染色质loop调控CXCR4的表达；⑤探索发现Aiolos与EZH2相互作用，共同调控NK细胞的发育和肿瘤的免疫微环境；⑥发表SCI论文11篇；⑦职称晋升2人次，博士研究生毕业并获得学位3人次。我们的工作对于实体肿瘤的发生发展机制提出了新的见解，拓展了Aiolos在肺癌发生发展中所发挥重要作用的理解，为其是否可作为一个新的治疗靶点提供理论依据。