血管内皮细胞及肿瘤血管凋亡诱导研究

【作者】 赵静；

【导师】 苗俊英；

【作者基本信息】 山东大学 ， 细胞生物学， 2006， 博士

【摘要】 血管内皮细胞的活化和增殖（Vascular Endothelial Cells，VEC）在血管形成中起关键作用[Pan X，et al，2004]，而诱导血管内皮细胞凋亡是诱导肿瘤血管退化的关键步骤[Greenberger S，et al，2004]。因此，研究血管内皮细胞凋亡的分子机制，可为建立防治肿瘤的抗血管形成疗法提供理论依据。另一方面，正常的血管形成为许多生理过程（如胚胎发育和伤口愈合等）所必需[Romagnani P，et al，2004]；血管内皮细胞凋亡异常导致的病理性血管形成，将导致胚胎发育异常甚至致死，同时也是多种不同疾病（如糖尿病性视网膜病，动脉粥样硬化和牛皮癣）的重要特征之一。因此，阐明血管内皮细胞凋亡的分子机制，可为上述血管类疾病的治疗提供新的切入点。 体外培养的人脐静脉内皮细胞（HUVEC）是研究内皮细胞凋亡机制的良好模型。目前多通过去除培养液生长因子，或者去除培养液生长因子并加入内皮细胞凋亡诱导剂（如manolide，MIBX等）的方法，诱导细胞的凋亡。虽然正常生物体内的VEC需要在生长因子存在的环境中生存，但是目前对正常条件下VEC凋亡的研究很少，VEC凋亡的分子机制仍不清楚。 许多研究表明，Akt／NOS信号通路与血管形成有关，也是血管内皮细胞重要的存活通路，但是该通路在血管内皮细胞凋亡中的作用机制还不清楚。 Fas（APO-1 or CD95）是Ⅰ型跨膜蛋白，在许多细胞中能传递凋亡信号，然而在血管内皮细胞中，APO-1／Fas信号通路却很难被激活。但最近发现，一些凋亡诱导剂能够通过激活Fas介导的信号通路，诱导血管内皮细胞凋亡。Fas在血管内皮细胞中的作用有待深入研究。 ROS可作为信号分子，参与多种生长因子介导的信号转导过程，其作用与它在细胞内的水平有关。由于不同凋亡诱导剂可诱导不同水平ROS的生成，因此，ROS在不同凋亡诱导剂诱导的血管内皮细胞凋亡中的作用还需进一步研究。 本实验室以前的研究表明，膜整连蛋白β₄，磷脂酰胆碱特异性磷脂酶C（PC-PLC）和P53可能是FGF-2调控的血管内皮细胞增殖和凋亡信号通路中的关键因子。但是，这些因子在血管内皮细胞凋亡中的作用机制还不清楚。更多还原

【Abstract】 Activation and proliferation of Vascular Endothelial Cells （VEC） have key functions in angiogenesis [Pan X, et al, 2004]. Apoptosis of vascular endothelial cells has important roles in anticancer therapeutics and in regulation of angiogenesis [Greenberger S, et al, 2004]. The research on the mechanisms of VEC apoptosis will offer theory basics for the anti-angiogenesis therapeutics. On the other hand, angiogenesis is necessary for normal physiological processes, such as embryonic development and wound repair [Romagnani P, et al, 2004]. Pathologic angiogenesis caused by VEC apoptosis abnormalities will cause many diseases, such as chronic inflammation and dysplastic transformation. Thus, clarifying of the mechanisms of VEC apoptosis might provide a successful therapeutic approach in diseases caused by abnormal angiogenesis.HUVEC is an excellent model for research on the VEC apoptosis. So far, VEC apoptosis induced by deprivation of FGF-2 and serum has been well studied. In vivo, VEC survival and growth are maintained in the presence of serum and growth factors. But how to trigger VEC apoptosis in the presence of FGF-2 and serum is not well known.Several lines of evidence suggest a link between angiogenesis and Akt/NOS signal pathway. But its function in VEC apoptosis was not well understood.Fas （APO-1 or CD95） is a type I membrane protein. It functions to transmit a death signal in many kinds of cells. But it is difficult to activate APO-1/Fas pathway in VECs. In fact, some apoptosis inducers can induce Fas mediated VEC apoptosis. Its function in VEC apoptosis needs further research.Accumulated evidence has demonstrated that ROS act as important signals in apoptosis. They run different functions according to their endocellular production. Because apoptosis inducers can induce diversity levels of ROS, the functions of ROS in VEC apoptosis induced by various apoptosis inducers were not well understood.Our recent research further demonstrated that integrin β₄, PC-PLC and P53 were更多还原