Study of the Regulative Role of Integrin Tension in the Formation and Function of Plasma Membrane Protrusions in Cancer Cells

转移是癌细胞侵入正常组织，是癌症患者死亡的主要原因。转移的细胞在其表面有特殊的部位，称为“侵入伪足”，使细胞扩散成为可能。 多条间接证据表明，侵袭伪足使用机械负荷是其侵袭功能的一部分。 然而，这些部队在入侵中如何发挥作用仍然是未知的。 研究人员开发了两种分子张力工具，并将用于测量侵入体的负载。 这项研究将确定张力如何影响侵袭伪足的形成和促进细胞运动。还将创建高分辨率细胞力图，作为检测临床前模型中癌细胞的生物力学测定。总的来说，这项研究将对侵袭性伪足的机械生物学产生有价值的见解，并可能创造一种新的工具，用于从生物力学上评估癌细胞入侵的可能性。 作为研究项目的一部分，研究人员将为通过NSF LSAMP IINSPIRE计划招募的本科生提供夏季研究机会，该计划招募代表性不足的本科生到实验室进行夏季研究。此外，为期一天的专题研讨会将在爱荷华州的PI大学部为60名本科生创建研究成像进展的各个方面。invadopodium是在癌细胞膜中形成的蛋白质复合物，其参与基质降解和癌症转移。机械敏感性蛋白整合素被认为是传递力的关键调节侵入伪足的形成和功能。然而，由于以前的技术障碍，这种力尚未在侵入足中进行研究。本项目的目标是表征整合素传递的分子张力（整合素张力），并研究其在侵袭伪足形成和功能中的基本作用。使用PI开发的创新分子张力工具，本项目的研究将首先以高分辨率和灵敏度校准和成像侵袭伪足中的整合素张力。整合素张力和各种结构蛋白将共同成像在0.3微米的分辨率，以揭示在invadopodia的力结构的相互作用。接下来，将使用张力调节剂将整联蛋白张力整体地和定量地敲低至设计水平，随后将检查侵袭伪足在基质降解中的结构缺陷和功能丧失，以确定整联蛋白张力在侵袭伪足活动中的作用。最后，整合素在侵袭伪足和局灶性粘连中贡献的高分辨率张力图将被测试作为从大量常规细胞中识别癌细胞的生物标志物。这种独特的生物力学分析有可能为检测患者血液样本中的循环肿瘤细胞提供一种快速方便的方法。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Metastasis, which is invasion of normal tissues by cancer cells, is the main cause of cancer patient death. The cells that metastasize have special sites on their surfaces call "invadopodia" that make it possible for the cells to spread. Multiple lines of indirect evidence suggest that invadopodia are use mechanical loads are part of their invasion function. How these forces function in invasion, however, remains unknown. Two molecular tension tools were developed by the investigators and will be used to measure loading of the invadopodium. This research will determine how tension affects invadopodia formation and facilitates cell motion. High resolution cellular force maps will also be created as a biomechanical assay for the detection of cancer cells in pre-clinical models. Overall, this research will yield valuable insights to the mechanobiology of invadopodia, and potentially create a new tool for assessing biomechanically the probability that cancer cells will invade. As part of the research project, the investigators will provide summer research opportunities to undergraduate students recruited through the NSF LSAMP IINSPIRE program which recruits underrepresented undergraduate students to labs for summer research. Also a one-day workshop featuring aspects of the research imaging progress will be created for 60 undergraduates in the PI's university department at Iowa State.The invadopodium is a protein complex formed in cancer cell membranes which is and involved in matrix degradation and cancer metastasis. Mechano-sensitive protein integrins are expected to transmit force to critically regulate the formation and function of invadopodia. However, such force has not been studied in invadopodia due to previous technical barriers. The goal of this project is to characterize integrin-transmitted molecular tension (integrin tension) and investigate its fundamental role in the formation and function of invadopodia. Using innovative molecular tension tools developed by the PI, the research in this project will first calibrate and image integrin tension in invadopodia with high resolution and sensitivity. Integrin tension and various structural proteins will be co-imaged at 0.3 micron resolution to reveal the force-structure interplay in invadopodia. Next, integrin tension will be globally and quantitatively knocked down to a designed level using a tension modulator, the consequent structural deficiency and function loss of invadopodia in matrix degradation will be examined to determine the role of integrin tension in the activities of invadopodia. At last, high-resolution tension map contributed by integrins in both invadopodia and focal adhesions will be tested as a biomarker for the identification of cancer cells from a large population of regular cells. This unique biomechanical assay has the potential to provide a fast and convenient approach for the detection of circulating tumor cells in patient blood samples.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.