Osteosarcoma Translational Research

描述（由申请人提供）：该项目旨在确定软骨细胞成熟在骨肉瘤（OS）肿瘤发生中的作用。长期目标是推进OS的诊断并确定OS治疗的新治疗靶点。骨肉瘤是儿童和年轻人中最常见的骨癌。它也是该年龄组癌症死亡的主要原因。OS开发的原因尚不清楚。以往的研究表明成骨细胞活性在其肿瘤发生中的重要性，因为OS的特征性特征是其肿瘤组织中的异常骨形成，并且OS内的主要细胞类型是成骨细胞。然而，除了成骨细胞，其他细胞类型，如软骨细胞，脂肪细胞，成纤维细胞也出现在OS。这些细胞类型如何有助于OS的发病机制仍然知之甚少。以前，在小鼠和人OS组织中都报道了软骨形成（Walkley et al.，2008年）。这是有趣的，因为软骨形成是软骨内骨形成的重要步骤，表明其在OS发育中的假定作用。在本申请中，研究人员假设软骨细胞成熟（软骨内骨形成期间软骨发育的关键阶段）可能通过与软骨细胞凋亡相关的机制在OS的启动和进展中发挥作用。为了验证上述假设，研究人员建议使用已建立的小鼠OS模型和他们自己的新型转基因小鼠模型以及人OS组织样本来描述软骨细胞成熟与OS发育的相关性。最近，来自主要研究者小组的初步结果和/或待发表的数据显示，在肥大软骨细胞中过表达Runx 2或P63的转基因小鼠分别导致软骨细胞成熟延迟或加速。鉴于Runx 2和P63基因在骨和癌症形成期间的重要功能，这些小鼠模型提供了独特的资源，以在基因上确定软骨细胞成熟如何影响p53和pRb缺陷型OS小鼠模型中的OS进展（Walkley et al.，2008年）。提出了三个具体目标。Aim 1预期显示Col 10a 1-Runx 2小鼠中延迟的软骨细胞成熟将由于抗凋亡标记物基因的表达增加而加速OS起始和进展。Aim 2有望显示加速Col 10a 1-TAP 63？小鼠延迟OS的发展，可能通过促凋亡机制。目的3：分析候选基因（如P53、P63、RB 1、SOX 9、RUNX 2等），使用组织阵列、qRT-PCR和新型COLD-PCR方法在人OS组织中研究与OS发病机制和软骨细胞成熟相关的基因。这些目标的成功完成将促进我们对OS病因学的理解，并确定软骨细胞成熟促进剂作为OS的新治疗靶点。

DESCRIPTION (provided by applicant): This project aims to determine how chondrocyte maturation plays a role in osteosarcoma (OS) oncogenesis. The long term goals are to advance the diagnosis of OS and to identify novel therapeutic targets for OS treatment. OS is the most common bone cancer in children and young adults. It is also the leading cause of cancer death in this age group. The causes of OS development are unknown. Previous studies have suggested the importance of osteoblast activity in its tumorigenesis, since the characteristic feature of OS is the abnormal bone formation in its tumor tissue and the predominant cell type within OS is osteoblast. However, besides osteoblasts, other cell types such as chondrocytes, adipocytes, and fibroblasts also appear within OS. How these cell types contribute to OS pathogenesis remain poorly understood. Previously, cartilage formation has been reported both in mouse and in human OS tissues (Walkley et al., 2008). This is intriguing, since cartilage formation is an essential step of endochondral bone formation, suggesting its putative role in OS development. In this application, the investigators hypothesize that chondrocyte maturation, a critical stage of cartilage development during endochondral bone formation, plays a role in the initiation and progression of OS, possibly through a mechanism relating to chondrocyte apoptosis. To test above hypothesis, the investigators propose to delineate the correlation of chondrocyte maturation with OS development using established mouse OS models and their own novel transgenic mouse models, as well as human OS tissue samples. Recently, preliminary results and/or pending publishing data from the principal investigator's group have shown that transgenic mice overexpressing Runx2 or P63 in hypertrophic chondrocytes result in delayed or accelerate chondrocyte maturation respectively. Given the important function of Runx2 and P63 genes during bone and cancer formation, these mouse models provide unique resources to genetically determine how chondrocyte maturation affects OS progression in a p53 and pRb deficient OS mouse model (Walkley et al., 2008). Three specific aims are proposed. Aim1 is expected to show that delayed chondrocyte maturation in Col10a1-Runx2 mice will accelerate OS initiation and progression due to increased expression of anti- apoptotic marker genes. Aim2 is expected to show that accelerate chondrocyte maturation in Col10a1- TAP63? mice delays OS development, possibly through a proapoptotic mechanism. Aim 3 focuses on analysis of candidate genes (such as P53, P63, RB1, SOX9, RUNX2, etc.), relating to both OS pathogenesis and chondrocyte maturation, in human OS tissues using tissue-array, qRT-PCR and novel COLD-PCR approaches. Successful completion of these aims will advance our understanding of OS etiology and identify promoters of chondrocyte maturation as novel therapeutic targets for OS.