Paxillin and Hic-5 in Coordination of Cancer Cell Invasion Mechanisms

描述（由申请人提供）：癌细胞从原发肿瘤块迁移并随后转移到远处器官被认为是癌症进展的致命步骤，与大多数癌症死亡有关。此外，单个癌细胞似乎能够通过在间充质和变形虫运动模式之间切换来逃避目前侵袭和转移的药物干预。控制这种表型可塑性的细胞机制尚不清楚。我们最近发现了密切相关的粘附相关支架蛋白paxillin和Hic-5在调节肿瘤细胞可塑性、侵袭和转移中的独特功能。在本提案中，使用已建立的癌细胞系以及从原发肿瘤中分离的细胞，我们将应用最先进的实时成像技术来跟踪肿瘤细胞形态和迁移，以及3d细胞外基质体外模型系统中的粘附和细胞骨架动力学。小鼠异种移植研究将用于评估paxillin和Hic-5信号传导对体内肿瘤进展和转移的相对影响。我们将使用RNA干扰和突变蛋白表达来剖析paxillin和Hic-5在控制肿瘤细胞侵袭模式中的各自作用，并确定相关的功能域和信号通路。我们将使用类似的方法来研究帕西林在调节基质金属蛋白酶-2 （MMP-2）运输和分泌以控制间质肿瘤侵袭策略中的作用。Hic-5在TGF-诱导的上皮间质转化过程中表达上调。Hic-5在TGF-依赖性细胞侵袭中的作用，通过基质降解侵过体的形成和功能，也将被研究。这些研究将为控制肿瘤细胞迁移和侵袭及其表型可塑性的协调提供潜在的细胞机制，并可能在未来为转移性癌症的检测或治疗提供新的策略。

DESCRIPTION (provided by applicant): The migration of cancer cells away from the primary tumor mass and their subsequent metastasis to distant organs is regarded as a fatal step in cancer progression and is associated with the majority of cancer mortalities. Furthermore, individual cancer cells appear to be able to evade current pharmacologic intervention of invasion and metastasis by switching between mesenchymal and amoeboid modes of motility. The cellular mechanisms controlling this phenotypic plasticity are poorly understood. We have recently identified distinct functions for the closely related adhesion-associated scaffold proteins paxillin and Hic-5 in the regulation of tumor cell plasticity, invasion and metastasis. In this proposal, using established cancer cell lines, as well as cells isolated from primary tumors, we will apply state-of-the art real-time imaging techniques to track tumor cell morphology and migration as well as adhesion and cytoskeletal dynamics in 3D-extracellular matrix in vitro model systems. Xenograft studies in mice will be used to evaluate the relative impact of paxillin and Hic-5 signaling on tumor progression and metastasis in vivo. We will use RNA interference and mutant protein expression to dissect the respective roles for paxillin and Hic-5 in controlling the mode of tumor cell invasion and identify the pertinent functional domains and signaling pathways. We will use similar approaches to study a role for paxillin in the regulation of matrix metalloproteinase-2 (MMP-2) trafficking and secretion to control mesenchymal tumor invasion strategies. Hic-5 is upregulated during TGF-¿-induced epithelial mesenchymal transition. The role of Hic-5 in TGF-¿-dependent cell invasion, through the formation and function of matrix-degrading invadopodia, will also be examined. The proposed studies will provide insight into the underlying cellular mechanisms controlling tumor cell migration and invasion and the coordination of their phenotypic plasticity and may in the future suggest novel strategies for detection or treatment of metastatic cancers.