内皮细胞Notch信号调控肿瘤血管结构的分子机制和在肿瘤血管"正常化"中的意义

The vessels of maliganant tumors are characterized by multiple structural abnormalities including tortuous shape, loosed endothelial interconnections, and incomplete smooth muscle cell coverage, among others, leading to aggravated tumor hypoxia, invasion and metastasis, and resistance to chemo- and radio-therapies. The molecular mechanisms underlying abnormal vessel structure in tumors are unclear. Recent literatures and our data have shown that blocking Notch signaling leads to structural abnormalities in tumor vessels, while activating Notch signaling ameliorates tumor vessel abnormalities, suggesting that Notch signaling might play an important role in the formation of normal structure in tumor neo-vasculature. In the current research, by employing endothelium-specific RBP-J conditional knockout and NICD transgenic mouse models, we will investigate the effects of endothelium-specific Notch blocking/activating on the structure of vessels in xenogenic tumors. We will also observe the effects of endothelium-specific Notch blocking/activating on tumor growth, metastasis, and chemotherapy, and the relationship with tumor vessel structure. Moreover, based on a preliminary comparison of gene expression profiles using gene chips, we will identify the downstream molecules of Notch signaling in the regulation of structural formation of tumor vessels, and try to elucidate the mechanisms of Notch signaling in the regulation of tumor vessel structure. Finally, we planned to establish methods to intervene with tumor vessel abnormality based on the roles of Notch signaling. These studies will reveal new molecular mechanisms underlying tumor vessel abnormalities, and will provide further evidence and targets for the intervening of tumor vessels.

肿瘤新生血管存在迂曲、内皮连接疏松、平滑肌覆盖不全等结构异常，加重肿瘤缺氧微环境和侵袭转移等恶性表型，促使肿瘤对化/放疗抵抗，但其分子机制不完全清楚。我们发现，阻断内皮Notch信号可引起肿瘤血管结构异常；而激活Notch可使肿瘤血管结构部分"正常化"，提示内皮Notch信号是影响肿瘤血管结构的关键通路之一。本项目拟采用内皮特异性RBP-J基因敲除/NICD转基因小鼠模型，探索Notch信号对小鼠移植瘤血管结构的影响，及其对肿瘤生长、转移和化疗应答的作用；在已完成Notch下游分子芯片筛选的基础上，鉴定Notch信号调控肿瘤血管结构的关键分子，阐明其作用机制；设计干预Notch信号促进肿瘤血管结构"正常化"的新分子，评价其对肿瘤血管结构的影响。本项目可揭示Notch信号对肿瘤血管结构的调控作用、其下游分子及与其他信号通路的相互作用，为干预肿瘤血管结构提供潜在新靶点，具有重要的理论和实际意义

肿瘤新生血管存在迂曲、内皮连接疏松、平滑肌覆盖不全等结构异常，加重肿瘤缺氧微环境和侵袭转移等恶性表型，促使肿瘤对化/放疗抵抗，但其分子机制不完全清楚。内皮Notch信号可能是影响肿瘤血管结构的关键通路之一。本项目拟采用内皮特异性RBP-J基因敲除/NICD转基因小鼠模型，探索Notch信号对小鼠移植瘤血管结构的影响，及其对肿瘤生长、转移和化疗应答的作用；鉴定Notch信号调控肿瘤血管结构的关键分子，阐明其作用机制；设计干预Notch信号促进肿瘤血管结构“正常化”的新分子，评价其对肿瘤血管结构的影响。研究结果表明在内皮细胞中激活Notch信号，可以促进肿瘤新生血管的正常化。进一步研究发现，Notch信号可以促使肿瘤血管内皮细胞发生转分化，转变为血管周细胞。这一转分化过程需要内质网应激信号通路的参与。发现肿瘤细胞的Dll3配体可以对肿瘤的炎症微环境应答，过表达Dll3可以在肿瘤细胞抑制Notch信号的活性，而Dll3对Notch信号的抑制作用与Dll3的细胞核转位相关。对Notch信号在内皮细胞中的靶分子进行了鉴定和研究。利用基因芯片筛选、鉴定了Notch信号新的下游miRNA分子，证实Notch信号可直接调控miR-342-5p宿主基因的启动子活性。利用体外转染上调或抑制血管内皮细胞的miR-342-5p的水平，证实该分子可调控内皮细胞增殖分化和血管新生。对miR-342-5p的下游靶分子进行了鉴定和功能研究，发现miR-342-5p可能通过Endoglin调控内皮细胞的增殖和迁移。发现Notch信号调控Nox4影响血管内皮细胞中活性氧族（ROS）的水平。以Notch配体Dll4为基础，自主设计了新的内皮靶向可溶性Notch配体mD4R，在大肠杆菌中表达mD1R蛋白并进行纯化，注射小鼠后发现mD4R可以有效调控地在血管内皮细胞中激活Notch信号，为进一步的转化研究奠定了基础。这些研究揭示了Notch信号对肿瘤血管结构的调控作用、其下游分子及与其他信号通路的相互作用，为干预肿瘤血管结构提供潜在新靶点。已发表研究论著3篇，待发表研究论著2篇。培养研究生三名，博士后一名。