Vessel-guided collective cancer invasion in vivo: molecular mechanisms and fate

肿瘤的侵袭和转移是肿瘤细胞的前迁移活动的结果，肿瘤细胞的前迁移活动在一定程度上是由肿瘤微环境提供的结构和分子信号诱导和指导的。肿瘤血管既是肿瘤细胞侵袭的结构支架，又是肿瘤细胞侵袭的分子支架。在结构上，血管提供排列的纤维和基膜ECM结构，以及细长的内皮细胞体，直接接触肿瘤细胞。分子促侵入元件是参与整合素的ECM结构域，释放的MMPs和其他用于受体加工的蛋白酶，以及支持异亲性细胞相互作用的细胞表面分子，包括ephrin-B2/EphB4， N-/VE-cadherin或NCAM。我们将研究肿瘤血管和新生血管如何促进肿瘤细胞的侵袭，方法是在nestin/GFP裸鼠中使用基于3D ECM的对抗实验和活体多光子显微镜对表达GFP/RFP的肿瘤细胞进行动态成像。利用时间分辨的地形重建和可溶性拮抗剂或RNAi的干扰，目标功能将是ECM重塑，以指导迁移和提供基底膜和其他排列的ECM结构。重点关注通过Ephrin/EphB通路介导的动态细胞-细胞接触的直接异源肿瘤细胞- ec相互作用。概念将通过体外ECM对抗试验建立，然后通过活体多光子显微镜验证。这些研究将为整合素介导的细胞-基质相互作用之外的肿瘤侵袭的分子开关提供新的概念。

Cancer invasion and metastasis are the result of promigratory activity in tumor cells which is in part induced and directed by structural and molecular signals provided by the tumor microenvironment. The tumor vasculature represents both, a structural and molecular scaffold for tumor cell invasion. Structurally, vessels provide aligned fibrillar and basemement membrane ECM structures together with elongated endothelial cell bodies for direct engagement of tumor cells. The molecular proinvasive elements are ECM domains engaging integrins, released MMPs and other proteases for receptor processing, and cell surface molecules supporting heterophilic cellular interactions, including ephrin-B2/EphB4, N-/VE-cadherin, or NCAM. We will investigate how tumor vessels and neovessels contribute to tumor cell invasion by using dynamics imaging in 3D ECM based confrontation assays as well as intravital multiphoton microscopy of GFP/RFP expressing tumor cells in the nestin/GFP nude mouse. Using time-resolved topographic reconstruction and interference with soluble antagonists or RNAi, target functions will be ECM remodeling for guided migration and the provision of basement membrane and other aligned ECM structures. A key focus will aim at direct heterologous tumor cell-EC interactions via Ephrin/EphB pathways mediating dynamic cell-cell contacts. Concepts will be established using ECM in vitro confrontation assays and then validated by intravital multiphoton microscopy. These studies will provide new concepts on molecular switches of tumor invasion beyond integrin-mediated cell-matrix interactions.