MicroRNA363受甲基化调控与难治性弥漫大B细胞淋巴瘤相关机制的研究

MicroRNA363 belongs to a member of oncogenic microRNA17-92 family. Our study has demonstrated its relation with treatment failure of diffuse large B cell lymphoma by immunochemothrapy, which was partly due to the effect of CACNA1C on rituximab-induced calcium influx and apoptosis. The project will further explore how microRNA363 is regulated by DNA methylation and associated with refractory behavior of diffuse large B cell lymphoma. Our preliminary study has revealed the control of microRNA363 expression by DNA methylation and activation of MAPK and Wnt pathways by it through bioinformation analysis.With many methods including gene array, immunoprecipitation，lentivirus transfection , mouse model, et al, we will confirm ①how microRNA363 is modulated by DNA methylation;②how microRNA363 activates oncogenic pathways;③if inhibitors of these oncogenic pathways can repress the growth of resistant lymphoma cells. Eventually, we expect to find novel approaches to overcome resistance.

MicroRNA363属于癌基因microRNA17-92家族的一员，前期研究发现它与弥漫大B细胞淋巴瘤免疫化疗治疗失败相关，通过靶基因CACNA1C影响利妥昔单抗诱导的钙离子内流和凋亡解释了部分治疗失败机制。本研究旨在进一步揭示microRNA363受甲基化调控与难治性弥漫大B细胞淋巴瘤相关的机制。前期研究显示microRNA363表达量与启动子甲基化程度呈负相关，生物信息学分析显示microRNA363高表达导致的治疗失败还与MAPK、Wnt癌基因通路活化有关。本研究利用基因芯片、免疫沉淀、病毒转染、移植鼠模型等多种方法，从体内和体外揭示①microRNA363受DNA甲基化调控的机制，以及去甲基化药物能否诱导治疗失败；②microRNA363高表达对癌基因通路影响的机制；③靶向癌基因通路药物对microRNA363耐药的逆转作用。通过研究最终发现克服耐药的方法。

microRNA在细胞内对基因表达发挥表观调控功能，研究发现许多microRNA与肿瘤发生、转移、耐药等过程密切相关。本课题组发现microRNA-363与利妥昔单抗耐药相关，但其引起耐药的机制不明。本研究以DLBCL细胞株、临床标本、动物模型作为研究对象，揭示了microRNA-363表达调控机制以及microRNA-363通过靶向下游分子介导利妥昔单抗耐药的机制。研究发现:1. microRNA-363高表达与DLBCL患者不良预后相关，microRNA-363的表达受启动子甲基化水平调控。2.microRNA-363过表达下调钙离子通道蛋白CACNA1C表达，减少利妥昔单抗介导的钙离子内流；L型钙离子通道激活剂/抑制剂的应用影响利妥昔单抗的疗效。3.CACNA1C与CD20存在蛋白间相互作用，microRNA-363过表达促进CD20蛋白降解，进一步加重利妥昔单抗耐药。4.microRNA-363过表达引起MAPK通路调节因子DUSP10表达下降，增加MAPK通路活性，促进细胞增殖。本研究获知了microRNA-363作为DLBCL预后因子和治疗靶点的可能性，揭示了microRNA-363引起DLBCL细胞耐药的机制，丰富了DLBCL耐药机制的理论基础，同时对临床工作具有一定的指导意义。

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