TGFβ3及相关分子在脊索瘤发病机制中的意义研究

Chordoma is a rare malignant bone tumor derived from the residual embryonic notochord tissue; the pathogenesis is largely unknown. By the means of miRNAs-mRNAs combined analysis previously, the applicant considers that the TGFβ3 and its related molecular miR-29 families played important role in chordoma pathogenesis. The present study, firstly, is to check the expression of TGFβ3 and miR-29 families in chordomas; then methods including DNA sequencing, TGFβ3 gene ChIp-Seq, miRNA transcriptome sequencing, will be used to check the gene expression, and cell signaling pathways related with TGFβ3 will be added to check its regulation pattern. Next, the zebra fish chordoma model and tumor cell lines, will be treated with TGFβ3 substitution and cell signaling pathways, to analysis the treatment effect, as well as the possibility of clinical application. As a result, the critical signaling pathways and networks of TGFβ3 will be evidenced.

脊索瘤是一种难治性罕见肿瘤,起源于原始胚胎脊索组织,治疗棘手,其病理机制不明。通过miRNAs-mRNAs相关性分析，申请人前期研究发现TGFβ3及相关因子（miR-29家族）在脊索瘤发病机制中具有重要意义，miR-29家族通过抑制TGFβ3表达诱导脊索瘤的产生。本项目利用已有的标本资料库及细胞系，进一步验证TGFβ3及相关因子在脊索瘤中的表达；并从基因表达、信号通道激活，分析TGFβ3为中心的分子病理学调控网络；进而通过斑马鱼脊索瘤模型和细胞系进行TGFβ3替代实验，从而获得TGFβ3及相关信号分子调控机制，为脊索瘤患者化疗治疗做铺垫。

脊索瘤是一种难治性罕见肿瘤，起源于原始胚胎脊索组织，手术全切率低，当前放化疗效果欠佳，预后差，是临床治疗的难题。本课题组通过miRNA测序、转录组学分析及双萤光素酶报告实验等证实在脊索瘤细胞中miR-29可直接靶向TGFβ3抑制其表达，揭示了脊索瘤中TGFβ3表达下调的关键机制。随后在TGFβ3基因敲除的斑马鱼模型及加入外源性TGFβ3处理的脊索瘤细胞中证实，敲低了的TGFβ3可使斑马鱼发生脊索瘤样改变，而外源性增加的TGFβ3可使细胞周期阻滞在G1期，阻碍细胞增殖，进一步证明了TGFβ3在脊索瘤发生中的关键作用。同时我们发现外源性TGFβ3处理可导致UM-Chor1细胞中miR-182表达下调，间接导致smad7表达上调进而抑制细胞迁徙和侵袭，而这与肺癌A549细胞系中的表现完全不同。在脊索瘤中smad7可负反馈调节TGFβ信号通路，而在大部分肿瘤中，该负反馈调节作用已不复存在。本研究创新性地提出以TGFβ为核心的独特的脊索瘤分子调控机制，对脊索瘤的发生发展机制有了更加深入的了解，细胞学、斑马鱼模型等实验取得了一定的成果，为TGFβ3作为药物治疗新靶点奠定了良好的基础。