PESO: Regulation of Mammary Epithelial Signaling by Local Matrix Stiffness

NSF-NCI肿瘤物理与工程科学(PISO)联合研究基金的主要研究目标是验证这样一种假设，即僵硬的气孔使乳腺上皮细胞(MECs)对张力敏感，张力导致整合素寡聚化和下游信号通路激活，已知的下游信号通路促进浸润性癌症。这一假说将在分离的微血管内皮细胞和3-D细胞外基质(ECM)中形成的腺泡细胞上进行验证。这项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，用于原位测量硬度的光钳活性微观流变学，用于在自然衍生的细胞外基质中建立拉伸和硬度梯度的剪切梯度装置，以及用于确定乳腺腺泡细胞对细胞外基质偶联张力的瞬时变化做出反应的细胞信号的实时成像。我们将寻求细胞外基质硬度与信号对拉力的反应程度之间的相关性。研究活动的成功完成将对癌症研究产生深远的影响。更好地了解微血管内皮细胞在二维和三维环境中对拉伸的反应将有助于我们理解它们在局限于腺泡、持续存在于增生性肿块或侵袭间质时如何对力做出反应。重要的是，这些发现将提供一块关键的拼图，将乳房X线摄影密度、间质硬度、作用力、整合素介导的信号转导和转移性乳腺癌的进展联系起来。将开发的方法学将有助于其他形式的癌症的研究，以及许多其他需要从机械角度进行研究的领域，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。这项提议的教育内容包括将研究纳入多学科课程，本科生通过短期暑期项目参与，以及在国家科学基金会资助的加州少数群体参与科学、技术、工程和数学联盟(CAMP)的支持下，代表不足的工程学学生参加。调查结果将通过外展计划、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.