Pax5调控的细胞抗原表达在复发耐药性多发性骨髓瘤发病机制中的作用及干预研究

Multiple myeloma (MM) is a B-cell malignant diseases and incurable.Relapse and drug resistance play a critical role in the failure of the MM treatment. Due to its molecular mechanism remains unclear, the ways of drug resistance reversion is very limited. The preliminary study have found that the loss of Pax5 gene in myeloma cells, the expression of non-B cell antigen and the lost of B cell antigen expression are involved in myeloma relapse and drug resistance development. There have been reported that Pax5 gene can inhibit the expression of non-B cell antigen and induce B-cell antigen expression. Our study have showed that cellular surface antigen expression could be induced and inhibited in vitro. Therefore, in this research projects, the gene transfection, RNA interference, gene chip, RT-PCR, Western blot, flow cytometry and animal experiments will be used to restore the Pax5 gene expression, to research for the ways to suppress the non-B cell antigen expression ,to induce B-cell antigen expression, and finally to reverse the drug resistance of myeloma cells. Furthermore,the Pax5-mediated sigaling pathway involved in myeloma cell antigen expression and the relationship between cellullar surface antigen expression and myeloma cell drug-resistance reversal will be studied. This research will help to provide a novel methed to overcome drug-resistance for refractory and relapse myeloma treatment.

多发性骨髓瘤（MM）是起源于B细胞的恶性疾病，目前尚无法治愈。复发和耐药是MM治疗失败的根本原因。由于其产生的分子机制仍不清楚，因此逆转耐药的方法也十分有限。前期研究发现，骨髓瘤细胞Pax5基因的丢失、非B细胞抗原的表达和B细胞抗原表达的丢失均参与疾病的复发和耐药的形成。文献报道，Pax5基因能抑制非B细胞抗原的表达和诱导B细胞抗原的表达；我们的研究发现，在体外，骨髓瘤细胞抗原分子的表达能被诱导和抑制。因此，本项目计划，采用基因转染、RNA干扰、基因芯片、RT-PCR、蛋白印迹、流式细胞和动物实验等技术，通过恢复Pax5基因的表达，寻找抑制非B细胞抗原的表达和诱导B细胞抗原的表达等方法，达到逆转骨髓瘤细胞耐药性的目的。并深入探讨Pax5对骨髓瘤细胞抗原表达的调控途径，以及调控细胞表面抗原参与细胞耐药逆转的分子机制，最终为复发和难治性MM的临床治疗提供新方法。

多发性骨髓瘤是一种起源于浆细胞的恶性肿瘤，浆细胞又有其特点， 最大的特点是不表达 Pax5 基因。 在 B 细胞中Pax5调控B 细胞的定向分化，Pax5阴性的B细胞具有多系分化潜能。失去 Pax5 基因表达的骨髓瘤细胞，也具有表达多系细胞表面抗原的特点，细胞的形态也发生了改变，我们通过基因转染技术构建过表达Pax5基因的U266细胞，发现Pax5过表达U266细胞的增殖及凋亡同空载组相比没有明显区别；但是通过生物信息及基因芯片分析，我们发现Pax5过表达U266细胞存在某些基因表达的变化，尤其是细胞分化相关基因，这为我们下一步研究提供了思路。在新药研究方面，发现克拉霉素可以通过干扰细胞周期，发挥抑制MM细胞增殖的功效;同时我们也推测线粒体外膜电压依赖性阴离子通道 1 (voltage-dependent anion channels, VDAC1)可以成为多发性骨髓瘤治疗的潜在靶标。这些研究为临床治疗多发性骨髓瘤提供了新的方向。