横纹肌肉瘤（RMS）是儿童常见软组织恶性实体肿瘤，迫切需要有效、低毒治疗方法。.DMAMCL是我国自主研发的小分子化合物。我们前期发现,大剂量DMAMCL诱导RMS细胞凋亡，但小剂量DMAMCL不引起细胞死亡但抑制增殖、出现细胞分化的形态学及标记分子表达的改变。通过转录组测序、生信分析及初步验证，提出科学假说：小剂量DMAMCL通过降低miR-122-5p水平来增加PMEPA1表达水平，PMEPA1表达水平升高抑制TGF-β信号通路，引起细胞分化。本研究拟从分子、细胞和动物水平，利用分子生物学技术，明确DMAMCL通过调控PMEPA1引起细胞分化的作用，研究miR-122-5p对PMEPA1的负向调控关系，阐明PMEPA1通过抑制TGF-β信号通路诱导细胞分化的机制。通过对DMAMCL在RMS中新作用、新机制研究，为临床治疗提供新方法、新靶点，为DMAMCL在RMS中临床应用奠定理论基础。

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, and an effective and low-toxic treatment is urgently needed. DMAMCL is a small molecule compound independently developed by China. We have previously found that high-dose DMAMCL induced RMS cell apoptosis, while low-dose of DMAMCL did not cause cell death but inhibited cell proliferation, induced morphological changes indicating cell differentiation, and changed the expressions of RMS marker molecules. Through transcriptome sequencing, bioinformatics analysis and preliminary verification, we proposed a hypothesis: low-dose DMAMCL increases the expression of PMEPA1 by decreasing miR-122-5p level, and elevated expression of PMEPA1 inhibits TGF-β signaling pathway and then causes cell differentiation. At the molecular, cellular and animal levels, by using molecular biological techniques, we will clarify the role of DMAMCL in inducing cell differentiation via up-regulation of PMEPA1, study the negative regulation of miR-122-5p on PMEPA1, and elucidate the inhibition of PMEPA1 on TGF-β signaling pathway during cell differentiation. Through the studies on the new function and new mechanism of DMAMCL in RMS, it will provide new methods and new targets for clinical treatment, and lays a theoretical foundation for the application of DMAMCL in RMS.