外泌体通过miR-28-3p-SPRED1通路增强多发性骨髓瘤细胞对硼替佐米抵抗的机制

多发性骨髓瘤（MM）的耐药是其治疗过程中遇到的主要障碍，然而其耐药的机制还没有完全被揭示。我们前期结果发现低氧培养条件下的骨髓基质细胞分泌的外泌体可以诱导MM细胞对硼替佐米（bortezomib）的耐药。通过miRNA测序，我们在低氧外泌体中发现了高水平的miR-28-3p，其高表达以及降低它的预测靶基因SPRED1都能够诱导MM细胞的耐药。据此我们猜想低氧骨髓微环境中的骨髓基质细胞分泌的外泌体能够传递高水平的miR-28-3p至MM细胞中，通过作用于SPRED1 mRNA的3' UTR来抑制其翻译，进而增强MM细胞对硼替佐米的抵抗。本项目拟利用慢病毒感染、荧光素酶报告系统、转录组测序、活体成像等实验工具和方法在体外和小鼠模型体内阐明低氧外泌体通过miR-28-3p-SPRED1通路增强MM细胞对硼替佐米抵抗的具体过程和机制，为找到克服MM耐药的治疗策略提供新的潜在靶点和科学依据。

Drug resistance in multiple myeloma (MM) is the main obstacle encountered in its treatment and the mechanisms of resistance have not been fully elucidated yet. Our recent results revealed that exosomes derived from hypoxic bone marrow stromal cells could induce resistance to bortezomib in MM cells. By miRNA sequencing, we found high levels of miR-28-3p in hypoxic exosomes, and both its high expression and the reduction of its predicted target gene Sprouty Related EVH1 Domain Containing 1 (SPRED1) were able to induce drug resistance in myeloma cells. Accordingly, we propose that exosomes secreted by bone marrow stromal cells in the hypoxic bone marrow microenvironment can deliver high levels of miR-28-3p to MM cells, inhibit SPRED1 translation by targeting the 3' UTR of its mRNA, and thus enhance the resistance of MM cells to bortezomib. This project proposes to elucidate the specific process and mechanism by which hypoxic exosomes enhance MM cell resistance to bortezomib via miR-28-3p-SPRED1 pathway in vitro and in vivo using lentivirus, luciferase reporter assay, RNA sequencing, and in vivo imaging. This project will provide new potential targets and more scientific basis for developing therapeutic strategies to overcome MM drug resistance.