A novel preclinical orthotopic-humanised osteosarcoma model - Creating a tissue engineered orthotopic humanised in vivo microenvironment for translational osteosarcoma research in respect to drug testing and new prognostic biomolecular markers

骨肉瘤患者的治疗选择通常包括化疗和手术切除。这些治疗策略在许多情况下对生活质量产生有害影响，并且通常无法预防致命后果。在过去的几年里，骨肉瘤的治疗在患者生存方面几乎没有什么进展。主要原因是缺乏新的和有效的代理人。许多候选药物在体外和体内表现出有希望的治疗潜力，但在人体试验时证明无效。这是由于一系列因素，包括癌细胞在不同微环境中的行为变化。作为一种骨肿瘤，骨肉瘤的生长受到细胞外骨成分和周围骨髓干细胞的影响。目前使用的体外和体内模型不能代表这种人体骨器官的复杂组成。特别是胫骨内肿瘤细胞注射到免疫功能低下的小鼠中被广泛传播，接受人骨肉瘤在鼠骨环境中生长的限制。该计划研究的主要目的是建立一种新的组织工程原位人源化体内骨肉瘤小鼠模型，其原发性肿瘤生长在股骨，周围是生理性人骨微环境，以尽量减少宿主生物体的干扰。将评价肿瘤生物学和临床相关生长特性，包括转移扩散成像。基因阵列分析将描述原位人源化股骨生长位点和其他生长位点（鼠胫骨内和皮下人源化异位位置）之间以及转移性病变中基因表达模式的差异。为了验证这个第一个原位人源化骨肉瘤模型作为药物测试平台，我们将评估多柔比星（根据COSS和EURAMOS治疗方案）和新mTOR抑制剂PP 242（抑制mTOR复合物1和2）的影响。我们的目标是确定癌症，原发性肿瘤和转移性病变的各个阶段的新生物标志物。这样的生物标志物为临床医生在化疗选择和手术管理的决策中提供了有价值的信息。这项研究可能为骨肉瘤患者的特异性治疗和风险适应性治疗提供进一步的研究。同时，将评估这种新的组织工程原位人源化模型在代表人类骨器官方面的准确性，作为血液学和骨骼学等其他科学学科研究的工具箱。

Treatment options for osteosarcoma patients usually include chemotherapy and surgical resection. These therapeutic strategies have a deleterious impact on the quality of life in many cases and often are not able to prevent fatal consequences. There has been little effort in osteosarcoma treatment in terms of patient survival in the last years. The main reason is the lack of new and effective agents. Many drug candidates demonstrated promising therapeutic potential in vitro and in vivo but prove to be ineffective when trialed in humans. This is due to a range of factors including variations in the behaviour of cancer cells in different microenvironments. Being a bone tumour, osteosarcoma growth is influenced by extracellular bone components and the surrounding bone marrow stem cells. The currently used in vitro and in vivo models fail to represent the complex composition of this human bone organ. Especially intratibial tumour cell injection into immunocompromised mice is widely spread accepting the limitations of human osteosarcoma growth within a murine bone environment. The main objective of the projected study is to create a new tissue engineered orthotopic-humanised in vivo osteosarcoma mouse model with a primary tumour growing at the femur surrounded by its physiologic human bone microenvironment in order to minimize interference by the host organism. Tumour biology and clinical relevant growth properties including imaging of the metastatic spread will be evaluated. Gene array analyses will depict differences in gene expression patterns between the orthotopic humanised femoral growth site and other growth sites (murine intratibial and a subcutaneous humanised heterotopic location) as well as in metastatic lesions. To validate this first orthotopic humanised osteosarcoma model as a drug-testing platform we will evaluate the influence of doxorubicin (according to the COSS and EURAMOS treatment protocol) and the new mTOR-Inhibitor PP242 (inhibiting mTOR-Complex 1&2). We aim to identify novel biomarkers for various stages of cancer, primary tumour and metastatic lesions. Such biomarkers provide valuable information for clinicians in decision making for chemotherapeutical options and surgical management. The projected study may provide one step further to patient specific osteosarcoma treatment and risk adopted therapy. Simultaneously, this new tissue engineered orthotopic-humanised model will be evaluated for its accuracy of representing the human bone organ as a toolbox for research in other scientific disciplines like haematology and osteology.