Identification of Regulating Mechanisms of TBXT Gene Expression in Chordoma

脊索瘤是一种罕见的恶性骨肿瘤。由于其发病率低，脊索瘤是所谓的孤儿疾病的一部分。脊索瘤沿着脊柱发生，主要发生在斜坡或骶骨。 治疗的选择是尽可能的完全切除。脊索瘤对常规化疗或放疗无反应。我们建立了世界上最大的脊索瘤细胞系组，并拥有超过50个脊索瘤的肿瘤库，并进行了临床随访。在最近的研究中，我们发现脊索瘤的HOX基因表达谱取决于它们是发生在斜坡还是骶骨。这些基因在前后体轴的发育中起着重要作用。这种差异表达表明斜坡和骶骨脊索瘤的生物学特性不同。在第一个试点研究中，我们表明，抑制HOX蛋白诱导脉络膜细胞系的凋亡。因此，HOX蛋白有可能成为治疗脊索瘤的靶点。我们第一次分析的结果表明，Brachyury是由miRNA调控的。因此，将详细研究该途径，以便能够调节Brachyury表达。 我们对脉络膜细胞系和肿瘤组织的明确收集是解决这些问题的基础。所需的所有方法和技术都是在我们研究所建立的，包括经典的细胞培养（刺激和抑制细胞生长和增殖以及小鼠异种移植），分子生物学方法（转染、细胞增殖和凋亡的测量、蛋白质印迹、免疫组织学/细胞学、定量实时PCR、细胞周期分析），生物统计分析（突变的注释和甲基化和基因表达的比较研究）。这是第一项旨在整合体外和原位数据的研究，利用已建立的细胞系收集和肿瘤库长期目标是通过调节蛋白质Brachyury作为脊索瘤生物学中的关键因子来确定治疗这种罕见疾病的新靶点。

Chordomas are rare malignant bone tumors. Due to their low incidence, chordomas are part of the so-called orphan diseases. Chordomas arise along the spine mainly in the clivus or the sacrum. Therapy of choice is the complete resection whenever possible. Chordomas do not respond to conventional chemo- or radiotherapy.We have established the worldwide largest panel of chordoma cell lines and have a tumor bank of more than 50 chordomas with clinical follow-up. In recent studies, we showed that chordomas have a HOX gene expression profile dependent on whether they arise in the clivus or the sacrum. These genes play an important role in the development of the anterior-posterior body axis. The differential expression points to a different biology of clival and sacral chordomas. In first pilot studies, we show that an inhibition of the HOX proteins induces apoptosis in chordoma cell lines. Therefore, HOX proteins may serve as possible targets for the therapy of chordomas.Brachyury has a key role in the biology of chordomas. The results of our first analyses suggest that Brachyury is regulated by miRNAs. Hence, this pathway will be studied in details in order to become able to modulate Brachyury expression. Our well defined collection of chordoma cell lines and tumor tissues are the basis to address these issues. All methods and techniques needed are established in our institute including classical cell culture (stimulation and inhibition of cellular growth and proliferation and mouse xenografting), molecular biological approaches (transfections, measurements of cell proliferation and apoptosis, Western blots, immunohisto-/cytology, quantitative real-time PCR, cell cycle analysis), and biostatistical analyses (annotation of mutations and comparative studies of methylation and expression of genes).This is the first study that aims at integrating in vitro and in situ data to gain deeper insights into the molecular biology of chordoma using an established cell line collection and a tumor bank. The long-term aim is to identify novel targets for therapy of this rare disease by regulation of the protein Brachyury as a keyfactor in chordomas biology.