PESO: Regulation of Mammary Epithelial Signaling by Local Matrix Stiffness

这项NSF-NCI肿瘤学物理与工程科学（PESO）联合研究资助的主要研究目的是验证硬口使乳腺上皮细胞（MECs）对张力敏感的假设，其中张力导致整合素寡聚化和下游信号通路的激活，已知可促进侵袭性癌症。这一假设将在分离的mec和在三维细胞外基质（ECM）中形成的腺泡上进行测试。本研究结合了一套强大的方法来研究这一假设，包括：用于估计粘附力的三维牵引力显微镜，用于原位测量刚度的光学镊子主动微流变学，用于在自然衍生的ecm中建立拉伸和刚度梯度的剪切梯度装置，以及细胞信号的实时成像，以确定乳腺腺泡如何响应ecm耦合张力的瞬时变化。将寻求ECM刚度和响应张力的信号程度之间的相关性。本次研究活动的顺利完成将对癌症研究产生深远的影响。更好地了解mec在二维和三维环境下对拉伸的反应，将有助于我们了解它们在局限于腺泡、持续增生肿块或侵入基质时对力的反应。重要的是，这些发现将为乳房x线摄影密度、基质硬度、力、整合素介导的信号传导和转移性乳腺癌的进展提供一个关键的谜团。所开发的方法将有助于研究其他形式的癌症，以及需要机械视角的许多其他研究领域，包括再生医学、干细胞生物学、发育生物学、心血管生物学和组织工程。该提案的教育组成部分包括将研究整合到多学科课程中，通过短期暑期项目让本科生参与，以及在美国国家科学基金会资助的加州少数民族参与科学、技术、工程和数学联盟（CAMP）的支持下，让代表性不足的工程专业学生参与。调查结果将通过外展项目、讲座和博物馆展览向公众广泛传播。

The primary research objective of this NSF-NCI Physical and Engineering Sciences in Oncology (PESO) joint research grant is to test the hypothesis that stiff stoma sensitizes mammary epithelial cells (MECs) to tensile forces, where tensile forces lead to integrin oligomerization and activation of downstream signaling pathways known to promote invasive cancer. The hypothesis will be tested on both isolated MECs and acini formed within a 3-D extracellular matrix (ECM). This research combines a powerful set of methods to investigate this hypothesis including: 3-D traction force microscopy for the estimation of adhesion forces, optical tweezers active microrheology for the in situ measurement of stiffness, a shear gradient device for establishing gradients of stretch and stiffness within naturally derived ECMs, and real-time imaging of cellular signals to determine how mammary acini respond to instantaneous changes in ECM-coupled tension. Correlations will be sought between ECM stiffness and the degree of signaling in response to tensile forces.Successful completion of the research activities will have a far-reaching impact on cancer research. A better understanding of MECs' response to stretch in both a 2-D and 3-D context will help us understand how they may respond to forces while confined to an acinus, persisting in a hyperplastic mass or invading the stroma. Importantly, findings will provide a critical puzzle piece linking mammographic density, stromal stiffness, forces, integrin-mediated signaling, and the progression of metastatic breast cancer. The methodologies to be developed will be useful in the study of other forms of cancer and in many other areas of research in need of a mechanical perspective including regenerative medicine, stem cell biology, developmental biology, cardiovascular biology and tissue engineering. The educational components of this proposal include the integration of research into a multidisciplinary course, the involvement of undergraduate students through short-term summer projects, and the participation of underrepresented engineering students with the support of the NSF funded California Alliance for Minority Participation in Science, Technology, Engineering and Math (CAMP). Findings will be broadly disseminated to the public through outreach programs, lectures and a museum exhibit.