阻断TrkB-BDNF信号传导通路对神经母细胞瘤细胞生长及凋亡的影响

Blocking TrkB-BDNF signal pathway decreases the livability of neuroblastoma cells

摘要:

目的：脑源性神经生长因子(BDNF)和其酪氨酸激酶受体B（TrkB）与神经母细胞瘤(NB) 细胞的化疗耐药及恶性预后密切相关。该研究探讨阻断TrkB-BDNF信号传导通路后，NB细胞对化疗药物敏感性的变化。方法：常规培养SH-SY5Y NB细胞，用nM浓度全反式维甲酸（ATRA）诱导TrkB高表达，加入BDNF、化疗药顺铂（CDDP）和特异性酪氨酸酶抑制剂K252a处理。MTT实验方法检测应用K252a前后细胞的存活率的变化；同时应用Western-blot方法检测应用K252a前后TrkB的磷酸化水平的变化；流式细胞仪（FCM）检测细胞凋亡率；透射电镜（TEM）观察凋亡细胞的形态与结构。结果：ATRA+BDNF+CDDP组细胞的存活率及凋亡率与对照组相比，差异无显著性（P>0.05）。而经K252a处理后，细胞对顺铂的敏感性增加，细胞的存活率明显降低，凋亡率明显升高，差异有显著意义。Western-blot分析显示K252a能够阻断TrkB的磷酸化。结论：阻断TrkB-BDNF信号传导通路可提高NB的化疗敏感性，逆转耐药。

Abstract:

OBJECTIVE: Brain-derived neurotrophic factor (BDNF) and its specific tryrosin kinase receptor-B (TrkB) are highly correlated to the chemoresistance of neuroblastoma (NB) cells and poor prognosis. This study observed the changes of the sensibility of NB cells to chemotherapy drug cisplatin (CDDP) before and after blockage of TrkB-BDNF signal pathway by specific tyrosin kinase inhibitor K252a. METHODS: Human NB cell line SH-SY5Y (SY5Y) was routinely cultured. Expression of TrkB was induced with nM all trans-retinoid acid (ATRA). Then BDNF, CDDP or K252a were added to the cultured SY5Y cells. Cell livability was assessed by methyl thiazolyl tetrazolium (MTT) assay. TrkB autophosphorylation was determined by Western blot analysis. Cell apoptosis rate was detected by flow cytometry (FCM). The conformation of apoptosis cells was observed by transmission electron microscopy (TEM). RESULTS: The livability and apoptosis rate in SY5Y cells treated with ATRA, BDNF and CDDP were not different from the blank control group. However, after K252a together with ATRA, BDNF and CDDP treatment, the sensibility of SY5Y cells to chemotherapy drug CDDP increased, the livability decreased and the apoptosis rate increased in SY5Y cells when compared with the blank control group (P<0.01). K252a treatment resulted in blockage of TrkB autophosphorylation. CONCLUSIONS: The blockage of TrkB-BDNF signal pathway by K252a use can increase sensibility of NB cells to chemotherapy and thus decrease the livability of NB cells.