Resistance to chemotherapy mediated by TrkB in neuroblastomas.
Resistance to chemotherapy mediated by TrkB in neuroblastomas.
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发表时间：
2002-11
期刊：
影响因子：
11.2
通讯作者：
R. Ho;A. Eggert;T. Hishiki;J. Minturn;N. Ikegaki;P. Foster;A. M. Camoratto;A. Evans;G. Brodeur
中科院分区：
文献类型：
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作者：
R. Ho;A. Eggert;T. Hishiki;J. Minturn;N. Ikegaki;P. Foster;A. M. Camoratto;A. Evans;G. Brodeur
神经母细胞瘤是一种常见的儿童肿瘤，起源于周围神经系统。好的神经母细胞瘤通常表达神经生长因子(NGF)的受体TrkA，而不好的MYCN扩增的神经母细胞瘤通常表达TrkB及其配体脑源性神经营养因子(BDNF)。在这里，我们提供了TrkB-BDNF途径与提高神经母细胞瘤的存活率和化疗耐药性相关的证据。将TrkB全长表达载体导入内源性表达BDNF的神经母细胞瘤细胞系SH-SY5Y，获得了中高表达的克隆。细胞在体外暴露于用于治疗神经母细胞瘤的化疗药物：阿霉素、依托泊苷(VP16)和顺铂。用四甲基偶氮唑盐(3-(4，5-dimethylthiazol-2-yl)-2，5-diphenyltetrazolium)比色法检测细胞存活率，用酶联免疫吸附试验(ELISA)检测细胞死亡。在所有情况下，表达TrkB的亚克隆都比亲本更耐药。此外，当TrkB酪氨酸激酶被Trk特异性抑制剂CEP-2563或BDNF中和抗体阻断时，对化疗的敏感性显著增加。我们还在TrkB的Ser-473位发现了AKT的组成性磷酸化，而在SY5Y细胞中只有极少量的AKT的组成性磷酸化。这些结果表明，TrkB-BDNF途径在接触DNA损伤试剂时提供了生存优势，因此，这种自分泌途径可能在介导与TrkB表达的神经母细胞瘤相关的耐药表型中发挥重要作用。PI3K/AKT生存通路的激活可能与表达TrkB的神经母细胞瘤的耐药性增加有关。
Neuroblastoma is a common childhood tumor derived from the peripheral nervous system. Favorable neuroblastomas usually express TrkA, the receptor for nerve growth factor (NGF), whereas unfavorable, MYCN-amplified neuroblastomas usually express TrkB and its ligand, brain-derived neurotrophic factor (BDNF). Here, we provide evidence that the TrkB-BDNF pathway is associated with enhanced survival and resistance to chemotherapy in neuroblastoma. We transfected the neuroblastoma line SH-SY5Y, which has endogenous expression of BDNF, with a full-length TrkB expression vector, and obtained clones with moderate or high levels of expression. Cells were exposed in vitro to chemotherapy agents used to treat neuroblastomas: doxorubicin, etoposide (VP16), and cisplatin. Chemoresistance was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for cell survival and by ELISA for cell death. In all cases, the TrkB-expressing subclones were more resistant to treatment than the parent line. Furthermore, when the TrkB tyrosine kinase was blocked with the Trk-specific inhibitor CEP-2563, or by neutralizing antibody to BDNF, sensitivity to chemotherapy was significantly increased. We also found constitutive phosphorylation of AKT at the Ser-473 site in TrkB transfectants, whereas there was only a minimal level of constitutive phosphorylation of AKT in SY5Y cells. These results show that the TrkB-BDNF pathway provides a survival advantage when exposed to DNA-damaging reagents, and, therefore, this autocrine pathway may play an important role in mediating the drug-resistant phenotype associated with TrkB-expressing neuroblastomas. Activation of PI3K/AKT survival pathway may contribute to the increased drug resistance in TrkB-expressing neuroblastomas.