Developing the coral implant model of bone metastasis

描述(由申请人提供)： 骨转移是晚期乳腺癌患者的一个重要临床问题。临床前模型的缺乏阻碍了用于治疗和控制骨转移的靶向治疗的发展，这些模型可以识别肿瘤细胞在骨微环境中被吸引和生长的分子机制。这项建议的目标是开发一种新的动物模型，利用体内产生的“活化”骨基质来研究转移性骨病的渗出和进展过程。这些研究代表了癌症生物学家和整形外科医生之间的合作，前者擅长从细胞和分子的角度进行转移，后者擅长一种新的组织工程骨骼形成模型。在体内，骨是通过将羟基磷灰石替代的海洋珊瑚支架连接到血管链或椎弓根上而生成的。移植物中充斥着循环中的骨祖细胞，类骨质可以在5周内发育。我们建议使用这种“活化”的骨骼来评估注射入椎弓根后小鼠肿瘤细胞的归巢和进展。肿瘤细胞将被标记有荧光素酶基因，以便使用生物发光成像技术进行可视化和随时间监测。这种方法比现有的方法有几个优点，包括肿瘤细胞的有限扩散，转移细胞负荷的定量评估，以及操纵骨骼微环境的单个成分的能力。在原理实验的证明中，我们将使用这种方法来解决这样的假设，即常驻骨细胞产生的基质金属蛋白酶MMP2和MMP9有助于恶性乳腺细胞在骨微环境中的定植和生长。这些研究将为进一步研究寻找治疗和控制乳腺到骨转移的新靶点奠定基础。

DESCRIPTION (provided by applicant): Metastasis to the bone represents a significant clinical problem for patients with advanced stage breast cancer. The development of targeted therapies for the treatment and control of bone metastasis is hindered by the paucity of preclinical models that would allow the identification of the molecular mechanisms by which tumor cells are attracted and thrive in the bone microenvironment. The goal of this proposal is to develop a novel animal model to study the processes of extravasation and progression of metastatic bone disease using an in vivo generated 'vitalized' bone matrix. These studies represent a collaboration between cancer biologists with expertise in metastasis from a cellular and molecular perspective, and orthopedic surgeons with expertise in a novel tissue engineered model of skeletogenesis. Bone is generated in vivo by ligating a hydroxyapatite-substituted marine coral scaffold to a vascular leash or pedicle. The graft becomes populated with circulating bone progenitor cells, and bone osteoid can develop within 5 weeks. We propose to use this 'vitalized' bone to assess homing and progression of murine tumor cells following injection into the pedicle. The tumor cells will be tagged with the luciferase gene to allow visualization and monitoring with time using bioluminescent imaging techniques. This approach provides several advantages over existing methodology, including the limited dissemination of the tumor cells, the quantitative assessment of metastatic cell burden, and the ability to manipulate individual components of the bone microenvironment. In proof of principle experiments, we will use this methodology to address the hypothesis that production of the matrix metalloproteinases MMP-2 and MMP-9 by resident bone cells contributes to the ability of malignant breast cells to colonize and grow in the bone microenvironment. These studies will lay the foundation for further studies to identify novel targets for the treatment and control of breast-to-bone metastasis.