DNMT3A/mi-378a/TBX3表观信号轴调控骨肉瘤恶性转化及干性维持的机制研究

骨肉瘤(OS)是最常见的原发恶性骨肿瘤。研究表明，肿瘤干细胞(CSCs)起始肿瘤形成并促进其恶性进展。我们前期联合肉瘤球培养及ALDH活性筛选从原代OS细胞中富集CSCs。miRNA测序显示miR-378a-3p在CSCs中显著缺失，且DNMT3A参与了其表达调控，而TBX3为miR-378a-3p靶基因并在OS细胞干性维持中发挥重要作用。本项目拟进一步在患者来源移植瘤（PDX）、转基因小鼠模型、临床标本等多层面，深入探讨miR-378a-3p在OS恶性转化及干性维持的作用；研究DNMT3A介导miR-378a-3p的甲基化沉默通过靶向TBX3在OS起始和干性调节中的关键机制；最后评估miR-378a-3p及其甲基化检测的临床意义。本研究将阐述DNMT3A/miR-378a/TBX3表观信号轴在OS恶性转化及CSCs调控中的潜在机制，为OS表观遗传学靶向治疗、提高患者整体预后提供新的途径！

Osteosarcoma (OS) is the most common primary malignant bone tumor. Studies have shown that cancer stem cells (CSCs) initiate tumor formation and promote its malignant progress. We previously enriched CSCs from primary OS cells by using the sarcosphere formation assay and ALDH activity assessment. MiRNA sequencing analysis showed that miR-378a-3p was significantly downregulated in OS stem cells, and DNMT3A might be involved in the regulation of miR-378a-3p expression. Furthermore, we also found that TBX3 was downstream target of miR-378a-3p and played a key role on the OS stem cell maintenance. In this study, we are to further: (1) explore the function of miR-378a-3p in malignant transformation and OS stem cell maintenance utilizing the transgenic mouse model and Patient-Derived Xenograft (PDX) model; (2) study the mechanism of DNMT3A mediated silencing of miR-378a-3p and the role of TBX3 in OS initiation and stem cell regulation; (3) evaluate the clinical significance of miR-378a-3p and its methylation. Our study will shed light on the underlying mechanism of DNMT3A/miR-378a/TBX3 epigenetic signaling axis in controlling the OS initiation and stem cell properties, which will be beneficial for developing the novel epigenetic targeting therapy and hereby improve the overall survival of OS patients.