VASH2促进胰腺癌细胞吉西他滨耐药的机制研究

Our previous studies have demonstrated that VASH2 promotes gemcitabine resistance in pancreatic cancer cells through the activation of JUN dependent RRM2 transcription. We also have identified the combined protein of VASH2 , an important tumor associated methylated protein-PRMT5. Therefore, in this study we will investigate the downstream signaling pathways of VASH2 protein from the perspective of protein methylation, in order to find out the molecular mechanism of JUN activation, which can explain the detailed molecular mechanisms of gemcitabine chemoresistance induced by VASH2 in pancreatic cancer cells. And VASH2-knockout mice model of spontaneous pancreatic cancer will be developped and used for further validation of gemcitabine resistant function of VASH2 in pancreatic cancer. We will provide evidences for the investigation of new molecular targets to improve the gemcitabine chemo-effect in pancreatic cancer.

我们先前的研究已经证实VASH2通过JUN依赖的RRM2转录激活表达来促进胰腺癌细胞吉西他滨耐药。我们还鉴定了VASH2的互作蛋白PRMT5（一种重要的癌相关甲基化修饰蛋白）。因此，本研究从蛋白质甲基化修饰的角度探讨VASH2的下游信号通路，旨在找出JUN激活的具体分子机制，从而可以解释VASH2促进胰腺癌细胞吉西他滨耐药的详细分子机制，并将在VASH2敲除的胰腺癌自发小鼠中进一步验证VASH2的促吉西他滨耐药功能，为改善胰腺癌吉西他滨化疗效果的新分子靶点研究提供依据。

VASH2（Vasohibin 2）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。在后续的研究中我们发现，VASH2通过Jun依赖的RRM2的转录激活来促进胰腺癌细胞吉西他滨化疗耐药。为研究VASH2的分子作用机制，我们通过亚细胞定位发现VASH2可定位于细胞核，随后我们采用染色质免疫共沉淀-测序（ChIP-Seq）实验证明VASH2具有染色质结合能力。通过蛋白质免疫共沉淀（Co-IP）＋液质二联（LC-MS）分析，鉴定出VASH2的互作蛋白：组蛋白甲基化转移酶PRMT5（Protein Arginine Methyltransferase 5）。后续我们发现PRMT5在胰腺癌中都高表达并与生存不良相关，PRMT5通过甲基化ST7组蛋白H4R3促进胰腺癌细胞的转移侵袭。PRMT5与VASH2蛋白互作并共同在促进胰腺癌恶性行为及吉西他滨耐药中起重要作用。另外，我们还发现Linc01232可通过抑制HNRNPA2B1的泛素化降解，激活A-Raf诱导的MAPK/ERK信号通路，促进胰腺癌转移。