Semaphorins与肿瘤的发生和转移

Semaphorins in occurrence and metastasis of tumor

Sem aphorins是一大类具有保守Sem a结构域的信号蛋白。该家族分为8个亚群,目前已发现30多个成员,有分泌型、跨膜型和GPI锚定3种类型。在病毒、非脊椎动物和脊椎动物中都已发现Sem aphorins分子的存在。该家族蛋白主要有2种受体:p lexins和neurop ilins,它们对Sem aphorins功能的发挥非常重要。Sem aphorins首先是作为神经系统中一种重要的神经导向分子而被发现和认识的。起初的研究多围绕其在神经系统轴突导向中所发挥的作用而进行,发现Sem aphorins分子可以抑制或促进轴突的生长。但现在越来越多的研究表明,除了在神经系统中具有重要作用外,Sem aphorins分子在肿瘤生长、血管内皮细胞迁移、免疫反应等方面也有重要的生物学功能。Sem aphorins分子通过促进或抑制肿瘤血管发生而对肿瘤的发生发展进行调节。

The Semaphorins are a large family of signaling proteins defined by the presence of the sema domain, a conserved and distinctive structure. This family currently is composed of more than 30 members that are divided into 8 classes. According to their structure, the Semaphorin proteins are divided into 3 kinds： secreted, transmembrane and glycosylphospsphatidylinositol （GPI） -anchored proteins. Both of them are conserved from virus to vertebrate. Till now, two major kinds of receptor plexins and neuropilins were found to play a crucial role in the signal transduction of semaphorins. More and more studies suggest that Semaphorins also have important roles in other processes except neural system, such as lymphocyte activation, control of tumor growth, vascular endothelial cell motility, and immunological reactions. In additon to regulating angiogenesis, semaphorins have effects on tumor growth and tumorigenesis. In this review, we mainly focus on the roles and mechanisms of Semaphorins playing in tumor progression, metastasis and tumor angiogenesis.