新型融合基因PTPRZ1-MET通过STAT3 信号上调外分泌性蛋白促进脑胶质瘤血管生成的机制研究

In previous study, we had found a recurrent fusion gene-PTPRZ1-MET (ZM) in gliomas. In tumor species, preliminary analysis has showed that phosphorylated ZM was related to STAT3, MAPK and AKT signaling, as well as cell proliferation and angiogenesis. However, experiments in vitro showed that ZM activate stably STAT3 signaling and is not related to proliferation of tumor cells. According to articles analysis, the contradiction on cell proliferation between in vivo and in vitro might result from the angiogenesis in tumor microenvironment. Therefore, we assumed that STAT3 phosphated by ZM switch to nucleus and then up-regulate the expression of exocrine protein which promotes tumor angiogenesis. Large sample data analysis, medium protein screening and validation, and glioma cell-Human Brian Microvascular Endothelial Cells (HBMEC) co-culture were used to select exocrine protein. Finally, the "ZM/STAT3/exocrine proteins "signaling was verified by intracranial planting glioma cells in situ on immunodeficient mice. This study will reveal the mechanism that ZM promotes tumor angiogenesis and provide new targets for drug selection and development to glioma patients with ZM fusion gene.

我们前期通过测序技术国际首次报道了胶质瘤中一频繁出现的新型融合基因PTPRZ1-MET（ZM）。临床标本信息显示ZM与细胞增殖和血管生成显著相关，并能够激活STAT3、MAPK和AKT等致癌通路。然而我们体外实验显示ZM并不能显著促进肿瘤细胞增殖，在细胞中仅能够稳定激活STAT3通路。我们认为肿瘤细胞微环境中的血管生成是ZM体内促增殖的原因。因此提出假说：肿瘤细胞中ZM激活STAT3后上调分泌性蛋白，促进周围血管生成。本项目拟通过大样本生物信息学分析、胶质瘤细胞与脑血管内皮细胞共培养、培养基蛋白筛选、RNA和蛋白水平验证、及小动物MRI和弥散加权成像等技术，体内外研究“ZM/STAT3/促血管分泌蛋白”信号轴的促血管生成作用。该研究将揭示ZM促血管生成的机制，并为临床筛选或研发针对ZM阳性肿瘤药物提供精确靶点。

脑胶质瘤是颅内最常见的一类恶性肿瘤，生存期短、致残率高，目前无有效的靶向药物。我们前期通过测序技术国际上首次报道了胶质瘤中一频繁出现的新型融合基因PTPRZ1-MET（ZM）。通过患者肿瘤标本信息我们发现ZM与血管生成相关，能够激活STAT3、MAPK和AKT等致癌通路。我们对15例ZM阳性和144例阴性标本全转录组数据进行分析筛选ZM调控基因；同时对三组小鼠肿瘤（对照组，ZM组，ZM+PLB-1001组）的转录组进行分析筛选ZM调控基因，患者和小鼠的数据进行交叉后共筛选到144个ZM相关基因，其中预测是STAT3的靶基因和与患者生存相关的基因共13个，经过PCR和western对RNA和蛋白表达验证我们最终确定能够编码分泌到细胞外蛋白的基因-IGF2BP3。实验发现IGF2BP3能够被ZM-STAT3信号通路激活，并与血管标志物CD31相关。IGF2BP3能够被ZM过表达的胶质瘤细胞合成，然后分泌到细胞外被血管内皮细胞摄取，干扰IGF2BP3后能够抑制血管内皮细胞的增殖、迁移和成管能力。因此我们的研究有可能为将来ZM靶向药物耐药提供另外一个敏感靶点。目前关于“ZM激活和检测”、“ZM-STAT3”研究结果已经发表2篇论文。