Understanding how cells invade through basement membrane in vivo

 描述(申请人提供)：基底膜是一种致密的、高度交联的细胞外基质形式，包围着大多数组织。在发育和免疫监视过程中，特化细胞获得了突破基底膜扩散并运输到感染和损伤部位的能力。细胞侵袭程序在许多疾病中调节不当，包括哮喘、关节炎、多发性硬化症和先兆子痫。侵袭性行为的不当获得也是癌症传播的基础，癌症占所有癌症相关死亡的90%。因此，了解细胞如何通过基底膜侵袭对人类健康具有重要意义。细胞侵袭涉及侵袭细胞、被侵袭组织和分隔它们的基底膜之间的动态相互作用。由于无法在体外概括这些复杂的相互作用，以及在实验上检验脊椎动物体内侵袭的挑战，细胞侵袭行为背后的机制仍然知之甚少。线虫锚定细胞入侵是一种实验上可获得的体内细胞入侵模型，它独特地将细胞-基底膜相互作用的亚细胞视觉分析与强大的正向遗传和功能基因组方法相结合。利用这些优势，我们的工作将表征一种新发现的细胞结构-侵袭性突起，这是一种特殊的膜域，在入侵过程中既能降解基底膜，又能物理上取代基底膜。我们还将确定入侵锚定细胞分泌基底膜结构蛋白LN如何促进侵袭。大多数转移性肿瘤过度表达层粘连蛋白，我们希望这项工作对了解癌症进展有广泛的相关性。我们的研究还意外地发现，在没有基质金属蛋白酶(MMPs)的情况下，锚定细胞可以通过物理移位基底膜来侵入基底膜。这一发现可能解释了为什么在转移性癌症患者的临床试验中抑制MMPs失败。我们的工作将决定 锚定细胞如何改变其侵袭模式，并研究线粒体产生的ATP的需求增加，以补偿MMPs的丢失。这些发现将开启细胞侵袭过程中能量需求的新研究领域，并为使用基质金属蛋白酶抑制剂靶向侵袭提供更好的方法。最后，我们的工作将描述一个新生的转录调控网络，它指定了侵袭性，从而解决了细胞如何被编程为侵袭性的关键问题。这些涉及专门的细胞侵袭机制、基底膜重塑和转录调控的综合研究与NIH的使命相关，因为它们将导致对细胞侵袭行为的基本生物学过程的深入理解，从而允许开发更好的治疗策略来限制癌症等人类疾病的侵袭。

 DESCRIPTION (provided by applicant): Basement membrane is a dense, highly cross-linked form of extracellular matrix that surrounds most tissues. During development and immune surveillance, specialized cells acquire the ability to breach basement membrane to disperse and traffic to sites of infection and injury. The cell invasion program is misregulated during many diseases, including asthma, arthritis, multiple sclerosis, and pre-eclampsia. The inappropriate acquisition of invasive behavior also underlies the spread of cancer, which accounts for 90% of all cancer- related deaths. Understanding how cells invade through basement membrane is thus of great importance to human health. Cell invasion involves dynamic interactions between the invading cell, the tissue being invaded, and the basement membrane separating them. Owing to an inability to recapitulate these complex interactions in vitro, and the challenge of experimentally examining invasion in vivo in vertebrates, the mechanisms underlying cell invasive behavior remain poorly understood. Anchor cell invasion in C. elegans is an experimentally accessible in vivo model of cell invasion that uniquely combines subcellular visual analysis of cell-basement membrane interactions with powerful forward genetic and functional genomic approaches. Using these strengths, our work will characterize a newly identified cellular structure-the invasive protrusion, a specialized membrane domain that both degrades and physically displaces basement membrane during invasion. We will also determine how secretion of the basement membrane structural protein laminin by the invading anchor cell facilitates invasion. Most metastatic tumors overexpress laminin, and we expect this work to have wide relevance to understanding cancer progression. Our studies have also unexpectedly revealed that the anchor cell can invade basement in the absence of matrix metalloproteinases (MMPs) by physically displacing the basement membrane. This finding might explain why inhibition of MMPs in clinical trials of metastatic cancer patients failed. Our work will determine how the anchor cell alters its invasion mode and investigate an increased requirement for mitochondrial generated ATP to compensate for the loss of MMPs. These findings will begin a new research area in energy requirements during cell invasion and inform better approaches to target invasion with MMP inhibitors. Finally, our work will characterize a nascent transcriptional regulatory network that specifies invasion, thus addressing the crucial question of how cells are programmed to be invasive. These integrative studies spanning specialized cellular invasive machinery, basement membrane remodeling and transcriptional regulation are relevant to NIH's mission as they will lead to a deep understanding of the fundamental biological process of cell invasive behavior, thus allowing the development of better therapeutic strategies to limit invasion in human diseases such as cancer.