Mineralized 3-D tumor models to study breast cancer bone metastasis

描述（由申请人提供）：项目总结乳腺癌经常转移到导致骨质溶解和临床预后不良的地方;然而，羟基磷灰石纳米晶体（HA，骨的矿物质成分）在这一过程中的作用仍不清楚，部分原因是缺乏适当的培养模型。这些研究的总体目标是设计矿化的3-D肿瘤模型，其捕获骨转移小生境内的固有3-D细胞-微环境相互作用以及可能由于疾病和老化而发生的HA的纳米结构改变。具体来说，我们将开发多孔聚（丙交酯-共-乙交酯）（PLG）支架，将HA纳米粒子的定义的物理化学特性和评估的适用性和相关性的3-D肿瘤模型，以测试HA和溶骨性骨转移之间的功能关系。这项工作将在三个具体的目标：在目标1中，我们将开发的3-D矩阵，通过合成单分散的HA纳米粒子与控制/可变的纵横比，堆叠，晶格取代，并将它们纳入多孔PLG支架。在目标2中，我们将利用这些支架来分析乳腺癌细胞的增殖和溶骨能力，以响应不同的HA纳米颗粒特性在体外，并评估可能参与这些变化的分子机制。在目标3中，我们将HA的物理化学性质与体内肿瘤生长和溶骨能力相关联，并验证目标2中鉴定的特定肿瘤细胞分泌因子的贡献。白细胞介素-8（IL-8）将是拟议的细胞因子信号转导研究的最初焦点，因为该因子调节转移相关的骨质溶解和肿瘤进展。此外，我们将使用矿化肿瘤模型来识别由HA的纳米结构变化调节的新因子，这些因子可以解释骨转移肿瘤细胞的分子特征。癌症生物学与工程和材料科学方法的新组合将产生高度可重复和病理相关的培养平台，使我们能够解卷积骨转移的复杂性，并确定改进治疗的分子靶点。通过阐明基于材料的机制的重要性，所提出的技术有可能挑战目前公认的骨转移作为一种仅由细胞和分子变化介导的疾病的范式。最后，所提出的3-D培养系统将使研究其他生理和病理情况的全新方法成为可能（例如，骨质疏松症，牙齿再生）以及它们对与骨矿物质的3-D相互作用的依赖。 公共卫生相关性：项目叙述：骨转移是全球女性乳腺癌相关死亡的主要原因;然而，骨矿物质羟基磷灰石在这一过程中的作用仍不清楚。本研究将建立一个三维培养平台，系统地阐明骨矿物质基质、乳腺肿瘤细胞行为和转移性骨质溶解之间的功能关系。我们的研究将联合收割机材料科学与工程和癌症生物学相结合，这种跨学科的方法不仅有可能彻底改变我们对骨转移的理解，而且还提供了一个广泛适用的培养模型来研究羟基磷灰石依赖的生理和病理过程。

DESCRIPTION (provided by applicant): Project summary Breast cancer frequently metastasizes to be where it leads to osteolysis and poor clinical prognosis; however, the role of hydroxyapatite nanocrystals (HA, the mineral component of bone) in this process remains unclear due, in part, to the lack of appropriate culture models. The overall goal of these studies is to design a mineralized 3-D tumor model that captures the intrinsic 3-D cell-microenvironment interactions within bone- metastatic niches and nanostructural alterations of HA that may occur due to disease and aging. Specifically, we will develop porous poly (lactide-co-glycolide) (PLG) scaffolds that incorporate HA nanoparticles of defined physicochemical characteristics and assess the applicability and relevance of this 3-D tumor model to test the functional relationships between HA and osteolytic bone metastasis. This work will be accomplished in three specific aims: In Aim 1, we will develop the 3-D matrices by synthesizing monodispersed nanoparticles of HA with controlled/variable aspect ratios, crystallinities, and lattice substitutions and incorporating them into porous PLG scaffolds. In Aim 2, we will utilize these scaffolds to analyze the proliferative and osteolytic capability of breast cancer cells in response to varying HA nanoparticle characteristics in vitro and evaluate possible molecular mechanisms that may be involved in these changes. In Aim 3, we will correlate the physicochemical properties of HA with tumor growth and osteolytic capability in vivo and validate the contribution of specific tumor cell secreted factors as identified in aim 2. Interleukin-8 (IL-8) will be the initial focus of the proposed cytokine signaling studies, as this factor modulates metastasis-related osteolysis and tumor progression. Additionally, we will use the mineralized tumor model to identify novel factors that are regulated by nanostructural changes of HA and that may explain the molecular signature of bone-metastatic tumor cells. The novel combination of cancer biology with engineering and materials science approaches will result in a highly reproducible and pathologically relevant culture platform that will allow us to deconvolute the complexity of bone metastasis and identify molecular targets for improved therapies. By elucidating the importance of materials-based mechanisms, the proposed technology has the potential to challenge the currently accepted paradigm of bone metastasis as a disease that is solely mediated by cellular and molecular changes. Lastly, the proposed 3-D culture systems will enable radically new approaches of investigation of other physiological and pathological situations (e.g., osteoporosis, tooth regeneration) and their dependence on 3-D interactions with bone mineral. PUBLIC HEALTH RELEVANCE: Project Narrative: Bone metastasis is the leading cause of breast cancer-related deaths among women worldwide; however, the role of the bone mineral hydroxyapatite in this process remains unclear. This research will develop a three-dimensional culture platform to systematically elucidate the functional relationship between the bone mineral matrix, mammary tumor cell behavior, and metastatic osteolysis. Our studies will combine materials science with engineering and cancer biology, and this interdisciplinary approach has the potential to not only revolutionize our understanding of bone metastasis, but also provide a widely applicable culture model to study hydroxyapatite-dependent physiological and pathological processes.