Development of a novel "all-human" animal model to study breast cancer metastasis to bone - comparison of transcriptional signatures from ex vivo cultured primary tumor cells and in vivo metastatic populations.

目前，乳腺癌相关转移性骨病的治疗选择通常局限于姑息治疗。因此，从分子水平上了解转移性骨病的发病机制是非常必要的。但目前使用的体外或体内模型并不能代表人骨基质的复杂成分。为了提供更适合人类特有的骨微环境，人们引入了所谓的骨芯片模型，该模型依赖于将人骨碎片皮下植入严重联合免疫缺陷小鼠体内。然而，这种模型有很大的局限性：骨片血运不佳，因此死骨不能反映真实的临床情况。骨屑的大小和形状很难控制，这给建立可重复性的模型带来了困难。使用组织工程化结构可能是一个极具吸引力的替代方案，因为它允许更高的重复性和对形状、大小和孔隙率的控制。在计划中的研究中，我们建议在基于2D和3D培养的模型以及免疫受损小鼠的异种移植瘤的模型中描绘乳腺癌细胞的比较转录组和甲基化图谱。此外，在体内模型中，我们提出了一种新的人类组织工程骨构造，除了比较转录组和甲基化图谱外，还研究了肿瘤-骨界面两侧的趋骨性。这种模型可以比骨芯片模型更好地概括患者体内发生的转移序列。此外，我们正在确定骨基质中对转移至关重要的成分，以及骨对乳腺癌的存在做出反应而表达的趋骨基因。这项拟议的研究将寻求解决与常见癌症动物模型在人类生物标记物和治疗药物的临床前评估中的有效性有关的重要问题。

Currently, treatment options of breast cancer-related metastatic bone disease are usually restricted to palliative therapeutic modalities. Hence, there is a great need to understand the mechanisms of metastatic bone disease at a molecular level. But the currently used in vitro or in vivo models fail to represent the complex composition of the human bone matrix. In order to provide a more appropriate human-specific bone microenvironment, the so-called bone chip model, has been introduced, which relies on the subcutaneous implantation of human bone fragments into severe combined immunodeficient mice. However, this model has major limitations: The bone chip gets poorly vascularized and hence the dead bone does not reflect the real clinical situation. It is very difficult to control size and shape of the bone chip which makes it difficult to establish a reproducible model. The use of tissue engineered constructs could be a highly attractive alternative, since it allows higher reproducibility and control of shape, size and porosity. In the projected study we propose to delineate the comparative transcriptome and methylation profiling of breast cancer cells in models based on 2D & 3D cultures and xenograft tumors in immunocompromised mice. Further, in an in vivo model we propose a novel human tissue engineered bone construct to investigate osteotropism from both sides of the tumor-bone interface in addition to the comparative transcriptome and methylation profiling. This model may recapitulate the metastatic sequence occurring in patients much better than the bone chip model. In addition, we are identifying components within bone stroma essential for metastasis, and osteotropism genes expressed by bone in response to the presence of breast cancer. The proposed research will seek to address important questions in relation to the efficacy of common cancer animal models in the pre-clinical evaluation of human biomarkers and therapeutics.