Fyn磷酸化caspase-9调控结肠癌细胞凋亡的机制研究

Exploring the proto oncogene that tightly related to colon cancer and evaluating the prospect of their clinical applications, can provide more options for precision medicine. Fyn is a non receptor tyrosine kinase of the Src family. It is involved in many kinds of human physiological functions and tumor progression. However, its role in human colon cancer is still not clear. Our preliminary data showed that Fyn was highly expressed in several colon cancer cells, while the expression was low in normal cells. Knockdown of Fyn attenuated 5-Fu induced apoptosis of colon cancer cells, which suggested that highly expressed Fyn may promote the apoptosis of colon cancer cells. We also found that Fyn directly phosphorylated caspase-9 and combined with caspase-9. The literature shows that tyrosine kinase phosphorylation of caspase-9 increased its activity. So we assume that Fyn may also promote the activity of caspase-9 by phosphorylation. This study will continue working based on existing data, determine the effect of Fyn on apoptosis in human colon cancer cells, and further explore the mechanism of regulating colon cancer apoptosis by Fyn phosphorylating caspase-9. Collect patient sample who suffered stage IV colon cancer and received preoperative 5-Fu chemotherapy, and then use the sample verify the relevance between Fyn and apoptosis, Our aim is to provide theoretical basis for improving the effect of colon cancer chemotherapy.

探寻与结肠癌发生高关联的原癌基因，并研究其临床应用前景，能够为精准医疗提供更多选择。Fyn是Src家族的一种非受体酪氨酸激酶，参与多种人体生理功能和肿瘤进程，然而其在人结肠癌中的作用仍不清楚。我们的预实验显示Fyn在部分结肠癌细胞中高表达，在结肠正常细胞中低表达。基因沉默Fyn减弱5-Fu诱导的结肠癌细胞凋亡，提示Fyn在结肠癌中高表达促进结肠癌细胞凋亡。我们还发现Fyn能够直接磷酸化caspase-9并与之相结合。文献显示酪氨酸激酶对caspase-9的磷酸化使其活性增高，因此我们假设同样是酪氨酸激酶的Fyn可能通过磷酸化促进caspase-9的活性。本课题将围绕现有基础进一步开展工作，确定Fyn对结肠癌细胞凋亡的影响，深入探索Fyn磷酸化caspase-9调控结肠癌凋亡的机制，收集术前经5-Fu化疗的IV期结肠癌患者标本验证Fyn与凋亡的相关性，为提高结肠癌化疗效果提供切实的理论依据。

Fyn是Src家族的一种非受体酪氨酸激酶，参与多种人体生理功能和肿瘤进程，然而其在人结肠癌中的作用仍不清楚。体外激酶试验发现Src家族激酶主要成员Src和Fyn均可在Y251位点磷酸化caspase-9，从而促进caspase-9活性，相关研究成果发表在Nature子刊Cell Death@Discovery上。我们对该现象的临床意义进行了探究，思考Src激酶抑制剂与传统化疗药物联合应用是否合适。本研究旨在探索Dasatinib是否会干扰5-Fu引发的致结肠癌凋亡的作用。结果，我们证实Src可在酪氨酸251位点上直接磷酸化caspase-9，引起caspase-9活性升高。Dasatinib通过抑制Src的活性而减弱5-Fu引发的致结肠癌凋亡的作用。我们的发现可能部分解释了在转移性结直肠癌中Dasatinib和FOLFOX联用不能获得有意义的临床效果这一现象。依托本课题，我们同时开展了另一项研究：探索HOTAIR, miR‐613和c‐met对视网膜母细胞瘤细胞的生存、凋亡及增殖的综合作用。我们发现视网膜母细胞瘤患者的HOTAIR上调和miR‐613下调显示出更差的生存状态。HOTAIR可直接靶向miR‐613，而c‐met则是miR‐613的直接靶基因，lncRNA HOTAIR/miR‐613/c‐met信号轴在调控视网膜母细胞瘤细胞的细胞活性、凋亡以及EMT特异性蛋白表达的作用或许可以为视网膜母细胞瘤的正确诊断和治疗策略提供证据，相关研究成果发表在二区杂志Journal of Cellular Molecular Medicine上。课题组在本研究周期（2017.01-2019.12）已发表SCI论文11篇，其中项目负责人杨鸽作为第一作者/共同第一/通讯作者7篇，以本项目编号81602154为第一标注论文4篇，第二标注论文2篇，第三标注论文1篇；杨鸽于2017/07-2018/07在美国加州大学圣地亚哥分校眼科遗传实验室从事博士后研究，研究方向为人工智能在医学诊断和治疗中的应用，作为共同作者发表在顶级期刊Cell杂志的论文“Identifying Medical Diagnoses and Treatable Diseases by Image-Based Deep Learning”入选Cell 2018年度十大论文。