[Mechanism of the inhibitory effects of thalidomide on expressions of VEGF and bFGF].

Objective: To investigate the inhibitory effects of thalidomide on the expressions of VEGF and bFGF in human lung adenocarcinoma A549 cells and human hepatocellular carcinomas HepG2 cells mediated by cereblon (CRBN). Methods: shRNA technology was used to construct the A549 cell line (A549CRBN) and HepG2 cell line (HepG2CRBN) with stable knockdown of CRBN, which was verified by real-time PCR and Western blot. A549 cells were divided into negative control group (A549luciferase) and CRBN down-regulation group (A549CRBN); HepG2 cells were divided into negative control group (HepG2luciferase) and CRBN down-regulation group (HepG2CRBN). The above cells were seeded into 6-well plates at 3×105 cells/well, and cultured in a 37℃, 5% CO2 incubator for 24 h. Then, 1 ml medium containing 100 μmol/L thalidomide (thalidomide group) and 1 ml medium containing 1‰ DMSO (control group) were added respectively, and the culture was continued for 24 hours before subsequent experiments. Each group was designed with three replicate wells. The effect of thalidomide on the activity of A549 cell line was detected by MTS assay. Real-time PCR was performed to detect mRNA expression levels of VEGF, bFGF and c-jun. ELISA assay was performed to detect protein expressions of VEGF and bFGF. Results: Compared with the control group, thalidomide at the concentrations of 1, 10, 50 and 100 μmol/L had no significant effects on the proliferation of A549 and HepG2 cells (P＞0.05). VEGF and bFGF levels in the A549CRBN or HepG2luciferase groups were significantly lower than those in the A549CRBN or HepG2CRBN groups (P＜0.05). Compared with the control group of the A549luciferase or HepG2luciferase, thalidomide inhibited the expressions of VEGF and bFGF in A549luciferase and HepG2luciferase cells (P＜ 0.05), but did not inhibit the expressions of VEGF and bFGF in A549CRBN and HepG2CRBN cells. Compared with the control group of the HepG2luciferase, thalidomide inhibited c-Jun expression in HepG2luciferase cells (P＜0.01), but did not significantly inhibit c-Jun expression in HepG2CRBN cells. Conclusion: The inhibitory effects of thalidomide on VEGF and bFGF expressions may be mediated by CRBN in A549 and HepG2 cells, and c-Jun may be one of the key transcription factors responsible for this inhibition.目的: 探讨Cereblon(CRBN)对沙利度胺抑制人肺癌A549细胞及人肝癌HepG2细胞分泌VEGF/bFGF的影响。方法: 采用慢病毒介导的短发夹RNA(shRNA)干扰技术建立稳定敲低CRBN的A549细胞系(A549CRBN)及HepG2细胞系(HepG2CRBN)并通过实时定量PCR(Real-time PCR)和蛋白质印记(Western blot)实验验证。将A549细胞分为阴性对照组(A549luciferase)、CRBN低表达组(A549CRBN);HepG2细胞分为阴性对照组(HepG2luciferase)、CRBN低表达组(HepG2CRBN),以上细胞按照 3×105 cells/well接种到6孔板中,放入37℃,5%CO2的培养箱中培养24 h,分别加入1 ml含100 μmol/L沙利度胺(thalidomide组)和1 ml 1‰ DMSO(control组)的培养液,继续培养24 h再行后续实验,每组设计3个复孔。MTS法检测沙利度胺对细胞增殖的影响;Real-time PCR检测VEGF、bFGF、c-jun mRNA表达,ELISA法检测VEGF、bFGF蛋白表达。结果: 与对照组比较,沙利度胺在浓度为1、10、50、100 μmol/L 时对A549 及HepG2细胞的增殖能力无显著影响(P＞0.05)。与A549CRBN或HepG2CRBN组比较,A549luciferase及HepG2luciferase组分泌的VEGF及bFGF均显著降低(P＜0.05)。与A549luciferase或HepG2luciferase细胞的对照组比较,沙利度胺可抑制A549luciferase和HepG2luciferase细胞的VEGF和bFGF的表达(P＜0.05),而对A549CRBN和HepG2CRBN细胞中VEGF和bFGF的表达无显著抑制作用;与HepG2luciferase细胞的对照组比较,沙利度胺可抑制HepG2luciferase细胞的c-Jun表达(P＜0.01),而对HepG2CRBN细胞的c-Jun表达无显著抑制作用。结论: 沙利度胺对A549和HepG2细胞VEGF和bFGF表达的抑制作用可能是通过CRBN介导的,而c-Jun可能是抑制作用的关键转录因子之一。.