Tang Yufu, Lv Pengfei, Sun Zhongyi, Han Lei, Luo Bichao, Zhou Wenping
Department of Hepatobiliary Surgery, The General Hospital of Shenyang Military Area CommandShenyang 110016, People's Republic of China; Post-Doctoral Station, The General Hospital of Shenyang Military Area CommandShenyang 110016, People's Republic of China.
Department of Hepatobiliary Surgery, The General Hospital of Shenyang Military Area Command Shenyang 110016, People's Republic of China.
Int J Clin Exp Pathol. 2015 Dec 1;8(12):15845-53. eCollection 2015.
14-3-3ζ protein, a member of 14-3-3 family, plays important roles in multiple cellular processes. Our previous study showed that 14-3-3ζ could bind to regulate the expression of hypoxia-inducible factor-1α (HIF-1α), which is induced by hypoxia and a crucial factor for induction of tumor metastasis. Moreover, we also have confirmed the response of 14-3-3ζ to hypoxia in our unpublished data as well. Thus, in the present study, we attempted to reveal that whether the regulation effect of 14-3-3ζ on HIF-1α functioned in a similar pattern as hypoxia. Stable regulation of 14-3-3ζ in human HCC cell line SMMC-772 and HCC-LM3 was achieved. The regulation of 14-3-3ζ on HIF-1α mRNA transcription was evaluated by luciferase activity assay and quantitative real-time PCR (qPCR). The effect of 14-3-3ζ on the production of HIF-1α and pathways determining HIF-1α's response to hypoxia was assessed using western blotting assay. Our results showed that regulation of 14-3-3ζ expression influenced the activity of HIF-1α, phosphatidyl inositol 3-kinase (PI3K), Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), and nuclear factor kappa B (NF-кB). Blocking of these pathways using indicated inhibitors revealed that 14-3-3ζ enhanced the production of HIF-1α via the activation of PI3K/Akt/NF-кB pathway, which was identical to hypoxia induced HIF-1α expression. For the first time, our study described the key role of 14-3-3ζ in the HIF-1α production in HCC cells. And the molecule exerted its function on HIF-1α both by directly binding to it and via PI3K/Akt/NF-кB signal transduction pathway.
14-3-3ζ蛋白是14-3-3家族的成员之一,在多种细胞过程中发挥重要作用。我们之前的研究表明,14-3-3ζ可以结合并调节缺氧诱导因子-1α(HIF-1α)的表达,HIF-1α由缺氧诱导产生,是诱导肿瘤转移的关键因素。此外,我们未发表的数据也证实了14-3-3ζ对缺氧的反应。因此,在本研究中,我们试图揭示14-3-3ζ对HIF-1α的调节作用是否与缺氧以相似的模式发挥作用。在人肝癌细胞系SMMC-772和HCC-LM3中实现了14-3-3ζ的稳定调节。通过荧光素酶活性测定和定量实时PCR(qPCR)评估14-3-3ζ对HIF-1α mRNA转录的调节作用。使用蛋白质免疫印迹法评估14-3-3ζ对HIF-1α产生的影响以及决定HIF-1α对缺氧反应的信号通路。我们的结果表明,14-3-3ζ表达的调节影响了HIF-1α、磷脂酰肌醇3激酶(PI3K)、Akt、细胞外信号调节激酶1/2(ERK1/2)和核因子κB(NF-κB)的活性。使用指定的抑制剂阻断这些信号通路表明,14-3-3ζ通过激活PI3K/Akt/NF-κB信号通路增强了HIF-1α的产生,这与缺氧诱导HIF-1α表达的情况相同。我们的研究首次描述了14-3-3ζ在肝癌细胞中HIF-1α产生中的关键作用。并且该分子通过直接与HIF-1α结合以及通过PI3K/Akt/NF-κB信号转导通路对HIF-1α发挥作用。