Understanding how cells invade through basement membrane in vivo

 描述（由申请人提供）：基底膜是一种致密的、高度交联的细胞外基质，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的能力，以分散和运输到感染和损伤部位。细胞入侵程序在许多疾病中被错误调节，包括哮喘、关节炎、多发性硬化症和先兆子痫。侵入性行为的不适当获得也是癌症传播的基础，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入对人类健康非常重要。细胞侵入涉及侵入细胞、被侵入组织和分隔它们的基底膜之间的动态相互作用。由于无法在体外重现这些复杂的相互作用，以及在脊椎动物体内实验研究入侵的挑战，细胞入侵行为的机制仍然知之甚少。C.锚细胞的侵袭elegans是一种实验上可获得的细胞侵入体内模型，其独特地将细胞-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个新发现的细胞结构-侵入性突起，一个专门的膜结构域，在入侵过程中降解和物理取代基底膜。我们还将确定如何分泌的基底膜结构蛋白层粘连蛋白的入侵锚细胞促进入侵。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理解癌症进展具有广泛的相关性。我们的研究还意外地发现，锚细胞可以在基质金属蛋白酶（MMPs）不存在的情况下通过物理置换基底膜侵入基底。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MMP的损失。这些发现将开始一个新的研究领域的能量需求在细胞侵袭和通知更好的方法，以靶向侵袭与MMP抑制剂。最后，我们的工作将描述一个新生的转录调控网络，指定入侵，从而解决细胞如何编程为侵入性的关键问题。这些综合性研究涵盖了专门的细胞侵袭机制、基底膜重塑和转录调控，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人类疾病（如癌症）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.