人脐血源基质细胞衍生微泡转移miR-150诱导MLL白血病细胞凋亡的研究

Patients with mixed lineage leukemia (MLL) gene-rearranged leukemia are usually associated with inferior outcome. Most of patients can not gain continues remission after chemotherapy or hematopoietic stem cell transplantation. We found human umbilical cord blood-derived stromal cells (hUCBDSCs) excert an apoptotic effect on MLL-rearranged leukemia cells. In-depth study on the molecular mechanism is an important basis for clinical therapeutic applications of hUCBDSCs on the treatment of MLL-rearranged leukemia. Our previous work has demonstrated that exosomes secreted by hUCBDSCs is directly related to the apoptosis of MLL-rearranged leukemia cells. Based on the miRNA chip assays and bioinformatics analyses, we further hypothesize that miR-150 in the exosomes is a key factor to induce the apoptosis of MLL-rearranged leukemia cells. This project is planned to further functionally dissect components of the exosomes produced by hUCBDSCs. Then, we will also study potential molecular mechanism involving in miR-150-induced apoptosis of MLL-rearranged leukemia cells. We will focus on the relationship between miR-150 and MLL fusion genes and the downstream target genes of miR-150. The resultant findings will help us to understand hUCBDSCs special effects on the treatment of MLL-rearranged leukemia and to accelerate therapeutic applications of hUCBDSCs in the clinic.

采用化疗和造血干细胞移植治疗伴有混合系白血病(MLL)基因重排的白血病疗效欠佳。人脐血源基质细胞(hUCBDSCs)具有诱导MLL白血病细胞凋亡的作用，深入探讨其分子机制，可望为改善MLL白血病疗效提供新的实验依据。项目组前期预实验发现hUCBDSCs分泌的微泡与MLL白血病细胞凋亡直接相关，通过芯片检测和生物信息学分析，进一步推测微泡内miR-150可能是hUCBDSCs诱导MLL白血病细胞凋亡的核心分子。本项目拟深入研究miR-150与MLL融合基因的调控关系，并在此基础上探讨miR-150对MLL白血病细胞内凋亡信号通路的活化/抑制效应，阐明以miR-150为主的hUCBDSCs衍生微泡诱导MLL白血病细胞凋亡的作用和可能机制，以期揭示hUCBDSCs在MLL白血病治疗方面的特殊生物学作用，为加快hUCBDSCs的临床应用提供可靠实验依据，进而为MLL白血病的临床治疗提供新的选择。

有混合系白血病(MLL)基因重排的白血病病人疗效差。人脐血源基质细胞(hUCBDSCs)具有诱导MLL 白血病细胞凋亡的作用，深入探讨其分子机制，可望为改善MLL 白血病疗效提供新的实验依据。本课题组建立了成熟稳定的人脐血基质细胞培养及微泡分离制备的方法。构建微泡转移模型，证实了人脐血基质细胞衍生微泡对MLL白血病细胞的促凋亡作用。使用miR-150 mimic/inhibitor 转染人脐血基质细胞，以改变其衍生微泡中miR-150的含量。提取转染miR-150 mimic/inhibitor人脐血基质细胞衍生微泡，与MOLM-13细胞进行共培养，进一步证明miR-150促进MLL白血病细胞凋亡的作用。运用生物信息学方法，确定了miR-150的下游靶基因BASP1\UBFD1，通过基因敲降实验确定了这两个基因在miR-150促MLL白血病细胞凋亡过程中的关键作用，进一步探索miR-150及其靶基因BASP1\UBFD1在促进MLL白血病细胞凋亡的调控通路。同时，构建MLL白血病小鼠模型， 在体实验证明miR-150影响小鼠白血病形成的生物学效应。本研究为系统阐明hUCBDSCs衍生微泡特殊生物学作用，加快hUCBDSCs向临床转化应用提供可靠的实验依据，也为MLL白血病新型治疗模式的探索提供可行的设计思路。