Objective: To investigate the effects of siRNA specificly for BDNF on apoptosis and invasion of HepG2 cells and its potential molecular mechanism. Methods; The expression of BDNF in cells was examined by western blot and BDNF secretion was evaluated by ELISA in human HCC cell lines of HepG2. BDNF knockdown was performed by specific BDNF - siRNA transfection in HepG2 cells, actin cytoskelelon was shown by FITC - phalloidin staining and the activations of RhoA, Racl or Cdc42 were determined by Western blot. Cell apoptosis and invasion were examined by flow cytometry and transwell assay respectively. Results: The expression of BDNF was found in HepG2 cells. BDNF concentration in the supernatant of HepG2 cells was 88.56 ±7.45 pg/ml. Inhibited expression of BDNF by specific siRNA showed impaired actin polymerization and decreased activations of RhoA or Racl in HepG2 cells. BDNF knockdown also induced apoptosis and suppressed invasion of HepG2 cells. Conclusion: BDNF knockdown inhibited cell invasion probably through the blocked actin polymerization and the correlated inactivation of RhoA or Racl. Aiming at BDNF/TrkB signaling interruption may be an effective strategy to prevent HCC progression.%目的:应用特异性siRNA下调HepG2细胞中BDNF表达,观察对细胞凋亡和侵袭的影响并探讨相关分子机制.方法:在人HCC细胞系HepG2中,采用Western blot方法检测BDNF的表达,采用ELISA方法检测培养液上清BDNF的分泌水平.特异性BDNF-siRNA转染细胞,采用FITC-phalloidin染色方法检测actin 细胞骨架的变化,采用Western blot方法检测细胞内RhoA、Rac1、Cdc42的活化情况.同时,流式细胞术检测细胞凋亡,Transwell小室测定细胞侵袭能力的变化.结果:HepG2细胞培养上清中BDNF含量为88.56±7.45 pg/ml.在HepG2细胞中,特异性BDNF-siRNA显著抑制BDNF的表达,干扰细胞内actin细胞骨架聚合,RhoA或Racl活性受到抑制,同时凋亡细胞数增加、细胞侵袭能力下降.结论:干扰BDNF的表达可以显著抑制细胞侵袭能力,这可能与阻断actin细胞骨架聚合、以及RhoA或Rac1活化相关.BDNF/TrkB信号通路可能作为阻断HCC发展演进的新靶点,有待于进一步深入研究.
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