VASH2与PRMT5/KIF11蛋白互作调控组蛋白修饰促进胰腺癌进展的研究

VASH2 was previously identified as an angiogenesis regulator. However we found VASH2 is transcriptional activated by epigenetic mechanism, and display a strong and various promotion effects in many solid cancers, including pancreatic cancer. To elucidate its action mechanism, by subcellular localization; VASH2 was found mainly within nucleus. By chromatin immunoprecipitation (ChIP) and sequencing, VASH2 was found to bind DNA around promoter region, which indicates it is a transcription regulator. By co-immunoprecipitation, and liquid chromatography with mass spectrometer (LC-MS), KIF11(Kinesin-like protein 11）and PRMT5（Protein Arginine Methyltransferase 5）were identified as combined protein of VASH2, they may potentially act as transporter, and bridge for VASH2 to chromatin histone，respectively. So the hypothesis was proposed: VASH2 form protein complex with KIF11 and PRMT5, transport into nucleus, then bind to promoter chromatin through PRMT5, regulate downstream genes transcription by histone methylation. The hypothesis was preliminary verified. This project will further verify and modify the hypothesis by a series of Co-IP and ChIP study in in-vitro and in-vivo models.

VASH2起初认为与血管生成相关。申请人进行系列原创研究发现VASH2在胰腺癌等肿瘤中表观遗传学激活，发挥强而广泛的促癌作用。为研究其作用机制，亚细胞定位、染色质免疫沉淀-测序（ChIP-Seq）发现VASH2定位于细胞核、并具有启动子区DNA结合能力，提示其转录调控功能。蛋白质免疫共沉淀（Co-IP）＋液质二联（LC-MS）分析，鉴定了两个VASH2互作蛋白：分子泵蛋白KIF11、组蛋白甲基化转移酶PRMT5，均为重要促瘤蛋白，是VASH2入核、结合染色质的可能机制和纽带。由此形成VASH2基本分子机制模型假说：VASH2与PRMT5/KIF11形成蛋白复合体，通过KIF11实现核转运、通过PRMT5结合启动子区组蛋白，共同调控甲基化修饰和下游基因转录。此假说经初步实验证实。本课题将采用一系列Co-IP、ChIP实验，在体外-体内研究中，对此假说进行验证、修正和深化。

VASH2起初被认为是一种血管生成因子，与缺氧诱导的血管生成相关。前期研究发现VASH2在胰腺癌等肿瘤中表观遗传学激活，发挥强而广泛的促癌作用。为研究其作用机制，亚细胞定位、染色质免疫沉淀-测序（ChIP-Seq）发现VASH2定位于细胞核、并具有启动子区DNA结合能力。蛋白质免疫共沉淀（Co-IP）＋液质二联（LC-MS）分析，鉴定了两个VASH2互作蛋白：分子泵蛋白KIF11、组蛋白甲基化转移酶PRMT5，均为重要促瘤蛋白，是VASH2入核、结合染色质的可能机制和纽带。研究过程中我们发现PRMT5及KIF11在胰腺癌中高表达且与生存不良相关，PRMT5通过甲基化ST7组蛋白H4R3促进胰腺癌细胞的转移侵袭，而KIF11促进胰腺癌细胞增殖。综上所述，PRMT5及KIF11在胰腺癌中发挥重要作用，而VASH2的分子功能的实现可能依赖这两者。