Role of Perivascular Mesenchymal Stem Cells (pMSCs) in the Bone Marrow Niche and the Extracellular Matrix in the Control of Skeletal Metastasis

技术摘要 骨骼是各种肿瘤和恶性肿瘤扩散的首选器官。主 本研究建议的目的是了解骨髓微环境的功能，以及 特别是它的血管周围成分，在建立骨转移。 提出的研究旨在检验这一创新假设，即间充质干细胞(MSCs)， 作为血管周围细胞(PMSCs)，它的作用是控制肿瘤细胞向骨骼的侵袭。这 新的假说为创新目标的治疗策略提供了临床相关信息 通过关闭转移细胞通过的门来减少循环癌细胞的植入 移植到正常的骨骼中。我们认为，抑制肿瘤细胞和PMSCs中的一个或联合 特定的基因将阻止或减弱体内的转移过程。 为了从实验上剖析控制渗出的各种细胞和细胞外基质成分， 我们已经设计并验证了一种独特的体内骨骼外人性化骨髓生态位模拟 站台(人性化的奥斯卡)。该平台的中心是使用多孔的磷酸钙 人骨髓间充质干细胞(HBM-MSC)负载后植入体内的陶瓷材料 免疫缺陷小鼠的背部。骨由HBM-MSCs锚定在陶瓷壁上 在这些位置和中心，宿主来源的血管在骨髓空间内有PMSCs。 我们已经证明，当黑色素瘤被注射到老鼠的血液中时，骨骼就会变成 黑色(黑色素)，就像栖息地的骨头一样。如果我们操纵分子的表达，我们是否提议 参与这一过程的，如PMC中的CXCL12或MCAM，小鼠的骨骼是黑色的，栖息地是 白色。这个黑白的结果为具体目标1奠定了基础，在这个目标中，我们剖析 骨髓间充质干细胞和血管周围基底膜在骨转移中的作用在具体目标2中，我们 建议确定癌细胞上表达的HSC-NICE配体分子在 驾驶SM。 我们已经建立了黑色素瘤的基线，黑色素瘤一旦转移，其致死率最高。 变成了骨头。这项提案还将重点研究利用乳腺癌细胞的分子机制。 台词。该平台的一个合理扩展是为患者控制 不同嗜骨性癌症的转移。 除了重大的直接临床影响，这项拟议的工作预计还将提供平台 对于未来解决可能影响其他骨转移的PMSCs的作用的项目，例如 调节局部抗肿瘤免疫反应、癌细胞休眠和肿瘤血管生成 作为研究其他嗜骨性恶性肿瘤(前列腺癌和肺癌)的模板，从而拓宽了 研究结果和结论的意义。

TECHNICAL ABSTRACT The skeleton is a preferred organ for cancer dissemination from various tumors malignancies. The main objective of this research proposal is to understand the function of the Bone Marrow microenvironment, and specifically of its perivascular components, in the establishment of skeletal metastasis. The studies that are proposed aim to test the innovative hypothesis that Mesenchymal Stem Cells (MSCs), as perivascular cells (pMSCs), function as gatekeepers controlling tumor cell invasion to the bone. This new hypothesis provides clinically relevant information for therapeutic strategies that innovately aim at reducing the engraftment of circulating cancer cells by closing the gate through which the metastatic cell transit into the normal bone. We propose that the inhibition of one or combination of tumor cells and pMSCs specific genes would prevent or attenuate the metastatic process in vivo. To experimentally dissect the various cellular and extracellular matrix components controlling extravasation, we have designed and validated a unique in vivo extraskeletal humanized bone marrow niche-mimicking platform (humanized Ossicle). This platform is centered around the use of a porous, calcium phosphate ceramic into which human bone marrow-derived MSCs (hBM-MSC) are loaded and then implanted into the back of immune deficient mice. Bone is fabricated onto the walls of the ceramic by hBM-MSCs anchored at these locations and, at the centers; the host-derived blood vessels have pMSCs within the marrow space. We have documented that when melanoma is injected into the blood stream of the mouse, the bones become black (melanin), as is the bone in habitat. If we manipulate the expression of molecules are we propose involved in the process, such as CXCL12 or MCAM in the pMSCs, the mouse bone is black and the habitat is white. This black-and-white result sets the stage for Specific Aim 1 where we dissect the participation of pMSCs and the perivascular basement membrane in driving Skeletal Metastasis. In Specific Aim 2, we propose to determine the participation of HSC-niche ligand molecules expressed on cancer cells in driving SM. We have established a baseline using melanoma, which has the highest rate of lethality once it metastasizes into bone. This proposal will also be focused on the study of molecular mechanisms using breast cancer cell lines. A logical extension of this platform is to provide a predictive diagnostic for the patients' control over metastasis for different osteotropic cancers. In addition to the significant direct clinical impact, this proposed work is expected also to provide the platform for future projects addressing the roles of pMSCs that may influence other skeletal metastasis, such as regulation of local antitumor immune response, cancer cells dormancy and tumor angiogenesis, and to serve as template for the study of other osteotropic malignancies (prostate and lung cancer), thus broadening the significance of the findings and conclusions.