ChIP-Seq分析胰腺癌中VASH2基因促癌作用的下游信号通路

Vasohibin 2(VASH2) was identified as angiogenesis factor in 2006. we found VASH2 was epigenetically transcription activated, then strongly promote tumorgenesis by various mechanism, including pro-angiogenesis, pro EMT, anti apoptosis, and so on. However, How and by what mechanisms for VASH2 to perform such strong and various tumorgenesis effect? Recently, we found VASH2 could regulate key genes transcription and expression in various signal pathway, moreover in pancreatic cancer, VASH2 was localized in nucleus by its nuclear binding sequence, the nuclear VASH2 could bind DNA as validated by chromatin immunoprecipitation (ChIP). So we are proposing that VASH2 is likely to act as "transcription factor", regulate key genes transcription on upstream of signal pathways, then cascade to promote tumorgenesis. This study will try to identify VASH2 binding DNA sequence by ChIP-Seq，combined with CO-IP to identify VASH2 binding protein complex, aiming to elucidate its direct mechanism and downstream signal pathway.

VASH2（Vasohibin 2）于06年鉴定为血管生成相关基因，前期研究我们率先发现VASH2在肝癌、胰腺癌等表观遗传学激活，发挥促血管生成、促EMT、抗凋亡等强而广泛的促癌作用，部分结果发表在Carcinogenesis和Oncogene杂志；然而VASH2通过何种机制发挥促癌作用？近期研究我们发现VASH2显著调节多个关键通路基因转录表达；同时发现VASH2具有核定位序列，在胰腺癌主要定位于细胞核，染色质免疫共沉淀ChIP分析证实其核型蛋白具有DNA结合能力；因此设想：VASH2可能类似"转录因子"，在信号通路上游调节关键基因转录表达，通过级联放大而发挥强而广泛的促癌作用。本课题将在胰腺癌中，采用ChIP-Seq明确核型VASH2结合的DNA序列，辅之以CO-IP的方法分离、鉴定出协助核型VASH2与DNA结合的蛋白复合体，旨在从源头阐明VASH2直接作用机制和下游信号通路。

VASH2（Vasohibin 2）于06年鉴定为血管生成相关基因，前期研究我们率先发现VASH2在肝癌、胰腺癌等表观遗传学激活，发挥促血管生成、促EMT、抗凋亡等强而广泛的促癌作用。近期研究我们发现VASH2显著调节多个关键通路基因转录表达；同时发现VASH2具有核定位序列，在胰腺癌细胞系中主要定位于细胞核，通过染色质免疫共沉淀ChIP分析证实其核型蛋白具有DNA结合能力；并且初步鉴定了两个VASH2互作蛋白，KIF11（Kinesin-like family member 11）和PRMT5（Protein Arginine Methyltransferase 5），而且证实了VASH2与PRMT5位于同一个蛋白复合体。在研究过程中，我们验证了VASH2具备细胞核内DNA的结合能力，其作用机制可能是通过VASH2/PRMT5蛋白复合体在细胞核中共同修饰组蛋白来调控下游基因的转录激活。我们还发现了VASH2具有显著促进胰腺癌细胞对吉西他滨耐药的作用。综上所述我们目前已经明确VASH2的DNA结合能力及结合基因.