Cytoskeletal Dynamics in Pancreatic Cancer Metastasis

 描述（由申请人提供）：胰腺癌是特别致命的，并且以侵袭性转移性侵袭而闻名。在之前的资助期间，我们收集了大量已发表和未发表的观察结果，以深入了解这些肿瘤的细胞如何传播。这些发现支持我们的中心假设，即侵袭性胰腺肿瘤细胞和相关基质细胞原位形成动态肌动蛋白为基础的“侵袭体”的前沿，选择性地招募特定的金属蛋白酶，以支持粘附，迁移和基质重塑转移侵袭。该假设将测试大的聚合物GT3-Dynamin 2的贡献，该聚合物GT3-Dynamin 2形成将侵袭体肌动蛋白为基础的网络连接到前进的细胞膜的收缩支架。我们将追求三个相关但不同的具体目标，这些目标将提供对机器的机械见解， 信号传导和降解过程被侵入的PDAC细胞和相关基质利用。这些目标包括：第一，定义Dyn 2/肌动蛋白为基础的机制，这是必不可少的“侵入体”的延伸，在迁移过程中在三维环境和原位，特别强调的表达，相互作用和功能的致癌肌动蛋白衔接子，α-辅肌动蛋白1和4，第二，了解调控侵入体动力学的小致癌GTP酶，直接结合Dyn 2，重点是治疗方法，第三，通过鉴定调节蛋白酶活性的新途径，确定Dyn 2中心侵袭体对基质重塑的机制。该提案将最先进的活细胞成像方法应用于多个实验模型系统，这些系统在3D环境中操纵肿瘤和基质细胞的混合群体，以及从遗传小鼠模型和人类PDAC患者中切除的肿瘤。从这些方法中收集到的信息将大大扩展我们对这种疾病的机械理解，同时开发新的疗法和治疗方法。

 DESCRIPTION (provided by applicant): Pancreatic cancers are particularly lethal and known for aggressive metastatic invasion. Over the prior funding period we have gathered substantial published and unpublished observations providing insight into how cells from these tumors disseminate. These findings support our CENTRAL HYPOTHESIS predicting that invasive pancreatic tumor cells and associated stromal cells in situ form a dynamic actin-based "invadosome" at the leading edge that selectively recruits specific metalloproteases to support adhesion, migration, and matrix remodeling during metastatic invasion. This hypothesis will test the contributions of the large polymeric GTPase Dynamin2 that forms a contractile scaffold linking the invadosome actin-based network to the advancing cell membrane. We will pursue three related but distinct specific aims that will provide mechanistic insights into the machinery, signaling, and degradative process utilized by invading PDAC cells and associated stroma. These aims include: One, defining the Dyn2/actin-based machinery that is essential for "invadosome" extension during migration in a 3-dimensional environment and in situ, with special emphasis on the expression, interaction, and function of the oncogenic actin adaptors, a-actinin 1 and 4, Two, understanding the regulation of invadosome dynamics by small oncogenic GTPases, that directly bind Dyn2, with an emphasis on a therapeutic approach, and Three, defining the mechanisms of matrix remodeling by the Dyn2- centric invadosome through the identification of novel pathways that regulate protease activity. This proposal will apply stat-of-the-art live-cell imaging methods to multiple experimental model systems that manipulate mixed populations of tumor and stromal cells in a 3D environment, as well as tumors resected from genetic mouse models and from human PDAC patients. The information gleaned from these approaches will greatly expand our mechanistic understanding of this disease while developing new therapies and treatments.