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目的探讨转录因子Sp1在低氧肝癌HepG2细胞血管内皮生长因子(VEGF)转录调控中的作用。方法实时定量PCR和免疫印迹法检测低氧肝癌HepG2细胞中Sp1和VEGF的表达,并应用Sp1特异性抑制剂普卡霉素(光神霉素A,plicamycin,mithramycin A)及Sp1-小干扰RNA(siRNA)干预上述实验检测VEGF mRNA的表达变化。结果低氧条件下肝癌HepG2细胞Sp1 mRNA、蛋白及VEGF mRNA的表达均呈时间依赖性明显增加,普卡霉素呈剂量依赖性抑制低氧诱导VEGF mRNA的表达。Sp1-siRNA转染HepG2细胞后,VEGF mRNA表达亦明显下降。结论低氧条件下,HepG2细胞Sp1蛋白及VEGF mRNA表达均明显增加。Sp1信号通路参与低氧诱导VEGF的转录调控。
Objective To investigate the role of transcription factor Sp1 in transcriptional regulation of vascular endothelial growth factor (VEGF) in HepG2 cells. Methods The expressions of Sp1 and VEGF in HepG2 cells were detected by real-time PCR and Western blotting. Sp1-specific inhibitor of mithramycin A (Sp1) and Sp1-small interfering RNA (siRNA) intervention in the above experiment to detect VEGF mRNA expression changes. Results The expression of Sp1 mRNA, protein and VEGF mRNA in HepG2 cells increased in a time-dependent manner under hypoxic conditions. Promycamycin inhibited the mRNA expression of VEGF induced by hypoxia in a dose-dependent manner. After HepG2 cells were transfected with Sp1-siRNA, the expression of VEGF mRNA was also significantly decreased. Conclusion Under hypoxic conditions, the expression of Sp1 protein and VEGF mRNA in HepG2 cells were significantly increased. Sp1 signaling pathway is involved in transcriptional regulation of hypoxia-induced VEGF.