染色体1q23上关键基因高表达参与多发性骨髓瘤染色体不稳定和耐药的研究

Multiple myeloma (MM) remains an incurable disorder of malignant plasma cell. A major reason for MM treatment failure is the existence of drug resistance developed during treatment. Using sequential gene expression profiling (GEP) samples, we defined common genes with significantly upregulated expression both after chemotherapy and at relapse.These genes were related to drug resistance. One gene ,NUF2, was located at chromosome 1q23. We analyzed the copy number aberrations of 1q23 by fluorescence in situ hybridization(FISH) and multiplex ligation-dependent probe amplification(MLPA). Amplification of 1q23 was found to be associated with a poor clinical outcome in newly diagnosed MM patients. NUF2 is a core components of the kinetochore essential for organizing microtubule attachment sites during mitosis. We hypothesize that high expression of NUF2 will induced drug resistance and chromosomal instability (CIN). High intraclonal heterogeneity and clonal evolution induced by CIN is a fundamenta driver of drug resistance of MM. We tend to knockdown and overexpress NUF2 in vitro and vivo to see the effect on proliferation, apoptosis, drug resistance and CIN. The key signaling pathways related to drug resistance and CIN will be studied. Our study will provide a series of experimental evidences and a novel clue for the CIN related drug resistance and lay a foundation for target therapy and reversing drug resistance.

目前为止，多发性骨髓瘤（MM）仍然是一种不可治愈的肿瘤。治疗过程中出现的耐药是MM难以治愈的重要原因。我们对MM初治、缓解和复发多个时间点进行序贯基因表达谱分析发现了一组与耐药相关基因的高表达。我们发现其中的NUF2基因所在的染色体1q23拷贝数扩增与患者的生存具有显著的相关性。NUF2是一种动点结合蛋白，参与调节有丝分裂过程中染色体的正常分离。我们推测NUF2表达异常的MM细胞可能对化疗药物不敏感，并通过影响染色体稳定性，发生克隆演变，导致MM肿瘤细胞对于多种化疗药物产生耐药。我们拟通过干扰NUF2基因表达水平，在体外和体内实验观察NUF2基因的表达对于MM增殖、凋亡、耐药和染色体不稳定的影响，寻找可能的信号途径。为研究染色体不稳定相关耐药提供实验依据和新思路，为靶向治疗和耐药逆转策略奠定基础。

多发性骨髓瘤（MM）仍然是一种不可治愈的肿瘤。治疗过程中出现的耐药是MM难以治愈的重要原因。我们对MM初治、缓解和复发多个时间点进行序贯基因表达谱分析发现了一组与耐药相关基因的高表达。我们发现其中的NUF2基因所在的染色体1q23拷贝数扩增与患者的生存具有显著的相关性。NUF2是一种动点结合蛋白，参与调节有丝分裂过程中染色体的正常分离。我们推测NUF2表达异常的MM细胞可能对化疗药物不敏感，并通过影响染色体稳定性，发生克隆演变，导致MM肿瘤细胞对于多种化疗药物产生耐药。. 我们通过对于大系列多发性骨髓瘤基因表达谱分析，发现NUF2基因表达水平与多发性骨髓瘤耐药明显相关；使用MLPA技术对于我院85例初治和55例复发MM进行分子遗传学检测，发现NUF2基因拷贝数扩增患者预后不良；敲除NUF2基因的骨髓瘤细胞系表现为增殖缓慢，对于硼替佐米敏感性明显增强，但是对于其他化疗药物的敏感性变化不大；体内动物实验：敲除NUF2基因的骨髓瘤细胞系在小鼠体内成瘤能力下降，并且表现出对于硼替佐米敏感性明显增强；对于NUF2基因的表达进行干扰，未发现NUF2基因与染色不稳定及DNA损伤修复相关，可能存在其他信号通路参与调解NUF2基因对于硼替佐米耐药。本课题证实NUF2在硼替佐米耐药中发挥重要作用。