食管癌细胞核中微丝结合捆绑蛋白Fascin的功能及其分子作用机制研究

我们以往曾研究发现，食管癌中位于胞浆的捆绑细胞微丝F-actin的蛋白Fascin异常高表达，发挥促癌功能。近年，我们通过免疫荧光观察发现，食管癌细胞中，Fascin还存在于胞核；此后我们分提核蛋白，通过免疫印迹确证Fascin的确存在于食管癌细胞的胞核，但其在食管癌细胞核中的功能尚不清楚。最近，我们进一步实验发现，在食管癌细胞的胞核中，Fascin与DNA损伤修复功能蛋白，不但共定位，而且还可能相互作用，暗示着在食管癌细胞的胞核中，Fascin可能参与DNA损伤修复，然而，Fascin与DNA损伤修复功能蛋白，究竟如何相互作用，即二者之间的精细相互作用情况，以及彼此间究竟如何协作，共同参与DNA损伤修复，亦即分子作用机制等更深层次的重要的科学问题尚有待于研究探讨。为此，本项目拟深入到分子水平，系统研究上述重要科学问题，深刻揭示食管癌中Fascin在胞核参与DNA损伤修复的分子作用机制。

We have previously studied that an F-actin bundling protein Fascin localized in cytoplasm and was abnormally highly expressed in esophageal squamous cell carcinoma (ESCC) to promote tumor progression. In recent years, using immunofluorescence assay we have found that Fascin also localized in nucleus, which was then confirmed by immuno-blotting assay after isolation of cytoplasmic and nuclear proteins from several ESCC cells. However, the function of nuclear-localized Fascin is still unknown. Further studies showed that fascin was localized at the ion radiation-induced foci (IRIF) after ion radiation treatment, and several DNA damage repair-related proteins were identified when immunoprecipitated Fascin for mass spectrum analysis, which suggested that nuclear localized Fascin may participate in DNA damage repair. However, many further important scientific issues, like how Fascin interacts with DNA damage repair proteins, such as the specific interaction position between them, and how Fascin coordinates with DNA damage repair proteins in DNA damage repair pathway, that is the molecular mechanism by which Fascin cooperates with DNA damage repair proteins, still need to be studied. Therefore, in this project we will explore answers to the above questions at molecular level and ultimately elucidate the molecular mechanism mediated by nuclear-localized Fascin in DNA damage repair pathway.