脑源性神经营养因子及其受体在多发性骨髓瘤中的表达及意义

[Expression and significance of brain-derived neurotrophic factors and receptors in multiple myeloma].

作者信息

Sun Chun-yan, Hu Yu, Wu Tao, Wang Ya-dan, He Wen-juan

机构信息

Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.

出版信息

Zhonghua Nei Ke Za Zhi. 2005 Dec;44(12):906-9.

PMID:16409727

Abstract

OBJECTIVE

To investigate the expression of brain-derived neurotrophic factor (BDNF) and its receptors in multiple myeloma (MM) cells and the biological effects of BDNF on MM cells.

METHODS

Transcription and protein expression of BDNF and its receptors (TrkB and P75(NTR)) in human myeloma cell lines (HMCLs) was determined with RT-PCR and Western blotting. BDNF levels in culture supernatant was determined with enzyme-linked immunosorbent assay. The expression of BDNF and TrkB by myeloma cells was studied with immunohistochemistry in bone marrow biopsy samples from 15 patients with MM. The effect of BDNF on the in vitro proliferation of HMCLs (RPMI 8226, U266, KM3) was examined with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The effect of BDNF on HMCLs migration was studied with modified Boyden chamber assay.

RESULTS

BDNF was expressed and secreted by HMCLs in high concentrations up to 14.7 microg/L. Furthermore, expression of its high affinity receptor TrkB was observed in HMCLs. BDNF expression by myeloma cells was demonstrated in 12 of the 15 patients with MM (80%), TrkB expression was demonstrated in all the 15 patients (100%), whereas control bone marrow samples showed weaker expression of BDNF in 2 of 9 (22.2%) and TrkB in 4 of 9 (44.4%). Functional studies demonstrated that BDNF has strong proliferative effects on HMCLs and proliferation of RPMI 8226 was enhanced by BDNF in a time- and dose-dependent manner. Moreover, BDNF has chemotactic properties on HMCLs. The maximal responses were seen at 50 microg/L for RPMI 8266 (P < 0.05) and 25 microg/L for KM3 cells (P < 0.01) as compared with nonstimulated controls.

CONCLUSION

BDNF and its high affinity receptor TrkB are co-expressed by MM cells. BDNF appears to have a major contribution to the pathophysiology of MM leading to proliferation and migration of MM cells. These provide the framework for novel therapeutic strategies targeting BDNF/TrkB signaling in MM.

摘要

目的

研究脑源性神经营养因子（BDNF）及其受体在多发性骨髓瘤（MM）细胞中的表达以及BDNF对MM细胞的生物学作用。

方法

采用逆转录聚合酶链反应（RT-PCR）和蛋白质免疫印迹法检测人骨髓瘤细胞系（HMCLs）中BDNF及其受体（TrkB和P75(NTR)）的转录和蛋白表达。采用酶联免疫吸附测定法检测培养上清液中的BDNF水平。通过免疫组织化学法研究15例MM患者骨髓活检样本中骨髓瘤细胞BDNF和TrkB的表达情况。采用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐（MTT）法检测BDNF对HMCLs（RPMI 8226、U266、KM3）体外增殖的影响。采用改良的Boyden小室法研究BDNF对HMCLs迁移的影响。

结果

HMCLs以高达14.7μg/L的高浓度表达并分泌BDNF。此外，在HMCLs中观察到其高亲和力受体TrkB的表达。15例MM患者中有12例（80%）骨髓瘤细胞表现出BDNF表达，15例患者均表现出TrkB表达（100%），而对照骨髓样本中9例中有2例（22.2%）BDNF表达较弱，9例中有4例（44.4%）TrkB表达较弱。功能研究表明，BDNF对HMCLs具有强大的增殖作用，BDNF以时间和剂量依赖性方式增强RPMI 8226的增殖。此外，BDNF对HMCLs具有趋化特性。与未刺激的对照组相比，RPMI 8266在50μg/L时（P<0.05）、KM3细胞在25μg/L时（P<0.01）出现最大反应。