uPAR调控肿瘤转移新途径的分子机制研究

Tumor cells invasion and metastasis is considered to be the primary cause of death in patients with malignant tumors. It is reported that the urokinase receptor (uPAR) plays a critical role in tumor invasion and metastasis. Currently, the exact molecular mechanisms of how uPAR regulates tumor metastasis and mediates intracellular signal transduction are still unclear and need further investigation. Therefore, the main goal of this project is to screen and identify novel uPAR-interacting proteins through a yeast two-hybrid approach and reveal functional significance of the interaction to further clarify the molecular biological function of uPAR. Our previous work has identified a heat shock protein MRJ as a novel partner of uPAR. Based on these results, this study will further confirm the interaction domain of MRJ and uPAR and their co-localization in the cell. In addition, experiments will be made to investigate the possibility whether MRJ, uPAR can form a complex with heat shock protein 70 (HSP70) to play the biological functions. Furthermore, the applicant will study the impacts of protein-protein interactions on tumor cells' apoptosis, proliferation, adhesion, invasion, migration, intracellular signal transduction and tumor metastasis within animals through in vitro (cell level) and in vivo (animal model) experiments. The current research will provide deeper understanding of the respective roles of uPAR in cancer metastasis regulation and represent novel therapeutic targets for cancer.

肿瘤细胞侵袭转移是引起恶性肿瘤患者死亡的首要因素。研究资料表明尿激酶受体（uPAR）在肿瘤浸润和转移中起到重要作用。目前，对于uPAR调控肿瘤转移及其介导胞内信号转导的精确机制还不是十分清楚。因此，本项目拟通过酵母双杂交技术筛选并鉴定与uPAR相互作用的新蛋白,揭示其相互作用的生物学意义，以期进一步阐明uPAR的分子生物学功能。申请人前期的工作已鉴定出热休克蛋白MRJ为uPAR的其中一个新的相互作用蛋白。本研究将在此基础上确定MRJ和uPAR的相互作用部位和细胞共定位情况，探讨MRJ、uPAR、HSP70形成蛋白复合物发挥生物学功能的可能性，并通过体外（细胞水平）和体内（动物模型）实验研究它们之间的相互作用对肿瘤细胞凋亡、增殖、粘附、侵袭、迁移、胞内信号通路、动物体内肿瘤转移的影响，深入研究uPAR在肿瘤转移中的调控机制，为恶性肿瘤的治疗提供新的分子靶点和治疗策略。

尿激酶受体（uPAR）在肿瘤浸润和转移中发挥着重要的作用。本课题通过酵母双杂交技术筛选并鉴定了几个能与uPAR相互作用的新蛋白，包括MRJ, HAX-1以及Spry-1。免疫共沉淀、细胞共定位等技术进一步确认了它们之间的相互作用。分子生物学和细胞生物学实验表明，HSP70, MRJ, uPAR可以形成蛋白复合物，通过影响细胞内的ERK、FAK等信号通路从而调控肿瘤细胞的增殖、粘附、迁移及侵袭等过程。进一步研究发现，在肿瘤细胞内干扰HSP70的表达可以增加肿瘤细胞对抗癌药物TRAIL的敏感性。此外，我们还发现uPA-uPAR系统的抑制剂ATF与其它肿瘤治疗药物联合应用可以显著抑制肿瘤的生长和转移。这些研究结果为恶性肿瘤的治疗提供了新的分子靶点和治疗策略。