RBMX介导FAM13A选择性转录参与调控脑胶质瘤上皮间质转化的机制研究

申请人前期研究发现RBMX、EZH2和H3K27me3及DNMT1在FAM13A不同启动子区富集，且RBMX表达与转录本FAM13A_RhoGAP和FAM13A_CCD表达及特定启动子区甲基化水平相关，参与调控PI3K/AKT通路及胶质瘤上皮间质转化。基于此，拟研究RBMX对胶质瘤上皮间质转化及恶性表型的影响；揭示RBMX介导FAM13A选择性转录的机制；解析FAM13A两转录本调控PI3K/AKT通路参与上皮间质转化的过程；探索靶向FAM13A_CCD的小分子化合物抑制上皮间质转化的治疗策略；体内实验验证RBMX调控FAM13A选择性转录及胶质瘤上皮间质转化的过程。本研究可揭示RBMX通过FAM13A两转录本调控PI3K/AKT信号通路，影响EZH2活性及DNMT1水平，介导FAM13A选择性转录，调控胶质瘤上皮间质转化的过程，为探索胶质瘤恶性进展机制及潜在治疗靶点挖掘提供新的理论依据。

RBMX protein involved in the tissue specific transcriptional regulation is rarely reported in gliomas. Recently, based on the TCGA transcript dataset, we observed that RBMX expression was correlated with FAM13A transcripts (named as FAM13A_RhoGAP and FAM13A_CCD, respectively) and implicated in the PI3K/AKT signaling pathway which has been previously reported to affect the protein level of DNA methyltransferase DNMT1 and the activity of EZH2. These domains included in the FAM13A_RhoGAP and FAM13A_CCD play important roles in regulating PI3K/AKT signaling pathway. In the preliminary experiments, RBMX overexpression could up-regulate E-cadherin and Claudin and down-regulate N-cadherin, β-catenin and Slug levels, suggesting that RBMX could suppress epithelial-mesenchymal transition in glioma. Quantitative PCR assays validated that RBMX knockdown reduced the FAM13A_RhoGAP transcript and increased the FAM13A_CCD transcript level, and vice versa. ChIP-seq data analysis revealed that DNMT1 could enrich in the FAM13A_RhoGAP promoter region (PRO1), and however, RBMX, EZH2 and H3K27me3 could jointly enriched in the FAM13A_CCD promoter region (PRO2). On these basis, we aim to explore the mechanism study of RBMX-mediated alternative transcription of FAM13A regulating epithelial-mesenchymal transition in glioma. We will study the biological process of RBMX regulating epithelial-mesenchymal transition and malignancy of glioma and clarify the mechanism of RBMX regulating PI3K/AKT signaling pathway to mediate alternative transcription of FAM13A genes via the alternative initiation induced by DNMT1 and EZH2. We will ascertain the function of FAM13A_RhoGAP and FAM13A_CCD regulating epithelial-mesenchymal transition and malignancy of glioma through Rho and PI3K/AKT signaling pathways. Furthermore, we will excavate some compounds targeting FAM13A_CCD to provide potential treatment strategy in glioma. Finally, we will carry out xenograft model experiments to validate the biological process of RBMX-mediated alternative transcription of FAM13A genes regulating epithelial-mesenchymal transition of glioma. This study will contribute to revealing that the mechanism of RBMX-mediated alternative transcription of FAM13A regulating epithelial-mesenchymal transition in glioma, which is intended to provide theoretical evidences in clinical marker excavation and individual treatment in glioma.