EGFL7转录激活在胰腺癌发生发展中的作用及其机制研究

Pancreatic cancer is definitely the most deadly malignant disease in the digestion system, and has no effective treatment. EGFL7 has been discovered recently as an angiogenesis factor,function structure similar to Notch receptors, but has been rarely reported in pancreatic cancer. Our previous study found that increased transcription activation and expression of EGFL7 in peripheral blood and tumor tissue of patients with pancreatic cancer,and is associated with tumor progression. The invasion and angiogenesis ability significantly weakened in pancreatic cancer cells after EGFL7 antibody blocking. Accordingly,we put forward the hypothesis: EGFL7 transcriptional activation is involved in the occurrence and development of pancreatic cancer through the Notch pathway. This project aims to observe the relationship between the EGFL7, Notch signal pathway and clinical pathological features of pancreatic cancer, and according to the human pancreatic cancer cell and animal models, using gene silencing and overexpression targeting the regulation of EGFL7 expression, timely blocking the Notch pathway, make sure the relationship between EGFL7 and the growth,angiogenesis,invasion and metastasis of pancreatic cancer from molecules, cells, tissues and animal levels,master the rules and methods of EGFL7 during the development of pancreatic cancer, explore the relative mechanisms, to provide theoretical and experimental basis for EGFL7 as a potential target to pancreatic cancer gene therapy.

胰腺癌发病隐匿、发展迅速，缺乏有效治疗手段。EGFL7是新近发现的促血管生成因子，结构类似Notch信号通路受体的功能区，但其在胰腺癌中的研究鲜有报道。我们前期研究发现胰腺癌患者外周血及肿瘤组织中EGFL7转录激活表达升高，且与疾病进展密切相关。EGFL7抗体阻断下胰腺癌细胞的侵袭能力和促血管生成能力明显减弱。据此提出假说：EGFL7转录激活并可能通过Notch通路参与了胰腺癌的发生发展。本项目拟深入观察EGFL7、Notch信号通路相关基因的表达与胰腺癌临床病理特征的关系，并针对人胰腺癌细胞及动物模型，运用基因沉默和过表达手段靶向调节EGFL7的表达，适时阻断Notch通路，从分子、细胞、组织及动物水平观察EGFL7与胰腺癌生长、血管生成、侵袭转移之间的关系，掌握其在胰腺癌发生发展中的规律和手段，探讨相关机制，为EGFL7可能成为胰腺癌基因治疗的潜在靶点提供一定的理论基础和实验依据。

胰腺癌发病隐匿、发展迅速，缺乏有效治疗手段。EGFL7是新近发现的促血管生成因子。基于临床胰腺癌样本，检测EGFL7基因和蛋白在肿瘤组织及患者外周血中的表达及分布，分析EGFL7的表达水平与肿瘤临床病理参数的相关性，深入探讨EGFL7与胰腺癌发生发展的关系。研究发现EGFL7在胰腺癌患者血清和癌组织中高表达，肿瘤组织中EGFL7的阳性表达与肿瘤的TNM分期、局部浸润、淋巴结转移、微血管密度等恶性进展指标呈显著正相关，与患者生存期负相关。进一步成功构建了特异性EGFL7基因的shRNA慢病毒载体。通过体外、体内实验，研究发现在体外，EGFL7分子能够促进胰腺癌细胞粘附水平、迁移及侵袭转移，促进细胞的恶性增殖，促进胰腺癌细胞的小管形成能力及鸡胚血管形成等恶性血管生成潜能。在体内，EGFL7分子能够促进胰腺癌肿瘤生长，局部浸润和腹腔、肺部远处器官转移。机制研究方面：①证实了EGFL7通过促进胰腺癌细胞上皮-间质转化（EMT）促进其恶性生物学行为。②高表达EGFL7下的胰腺癌细胞EMT标记物如E-cadherin、N-cadherin、Vimentin等的表达发生相应改变，而基因沉默EGFL7后，其通过靶向Snail、Slug等的下调逆转了EMT过程，该研究结果深入阐述了EGFL7基因的恶性生物潜能的关键机制，为其成为临床治疗的潜在分子靶点提供了进一步的理论基础和实验依据。.