缺氧诱导因子-1与细胞凋亡

缺氧诱导因子 1(HIF -1)是一种主要由缺氧诱导细胞产生的重要的转录因子。HIF- 1的表达水平与糖酵解、细胞周期阻滞、细胞生存与增殖、血管新生、血管舒缩、红细胞生成、肿瘤生长,转移以及肿瘤多药耐药等许多生命活动密切相关。HIF- 1通过调控凋亡相关基因的转录在促细胞凋亡和抗细胞凋亡中都发挥着重要的作用。     

缺氧诱导因子-1与类风湿关节炎

缺氧诱导因子-1（HIF-1）是一种由缺氧诱导细胞产生的调节细胞氧平衡和缺氧反应基因表达的核转录因子。缺氧条件下，细胞核产生HIF-1与靶基因结合，促进靶基因转录，引起一系列细胞对缺氧的反应，在促进糖酵解、促进血管生成、红细胞生成及调节血管舒缩等方面具有重要的作用。在类风湿关节炎（RA）中，HIF-1的表达增加可能通过上调血管内皮生长因子及其受体表达调控糖酵解代谢，从而启动并持续炎症反应，上调转录因子Ets-1的表达，激活CXCL12／CXCR4通路，与诱导型一氧化氮合酶相互作用及影响细胞凋亡等机制参与RA的发病。HIF-1为RA的基因治疗提供了新途径。     

缺氧诱导因子-1与类风湿关节炎

缺氧诱导因子-1(HIF-1)是一种由缺氧诱导细胞产生的调节细胞氧平衡和缺氧反应基因表达的核转录因子。缺氧条件下,细胞核产生HIF-1与靶基因结合,促进靶基因转录,引起一系列细胞对缺氧的反应,在促进糖酵解、促进血管生成、红细胞生成及调节血管舒缩等方面具有重要的作用。在类风湿关节炎(RA)中,HIF-1的表达增加可能通过上调血管内皮生长因子及其受体表达调控糖酵解代谢,从而启动并持续炎症反应,上调转录因子Ets-1的表达,激活CXCL12/CXCR4通路,与诱导型一氧化氮合酶相互作用及影响细胞凋亡等机制参与RA的发病。HIF-1为RA的基因治疗提供了新途径。     

缺氧诱导因子-1和妇科肿瘤

缺氧诱导因子是机体组织、细胞适应缺氧环境、缓解对氧和能量的需求、维持内环境平衡的关键,其中发挥核心调控作用的中心枢纽是缺氧诱导因子-1α（hypoxia inducible factor-1α,HIF-1α）。HIF-1α主要在细胞内发挥应答反应以维持对缺氧耐受,可以通过许多不同的受体介导不同的作用肿瘤在发生发展的过程中不乏缺氧过程,且越来越多的研究表明HIF-1和肿瘤的生物学密切关系,HIF-1引起许多学者的关注。本文主要介绍对HIF-1α的研究进展以及针对HIF-1α的靶向治疗研究、特别是其与妇科肿瘤的关系。     

缺氧诱导因子1研究进展

缺氧诱导因子1(HIF-1)在缺氧诱导的哺乳动物细胞中广泛表达,为缺氧应答的全局性调控因子。HIF-1由HIF-1α和HIF-1β两种亚基组成,为异源二聚体转录因子。HIF-1α、HIF-1β和近年来发现的HIF-2α一样均属于bHLH转录因子超家族中的PAS亚族。HIF-1α的bHLH和PAS结构域与二聚化及DNA结合活性有关,TAD结构域则主要参与转录激活。HIF-1α的全长基因已克隆并在人和小鼠中定位。通过作用于靶基因的缺氧反应元件(HRE),HIF-1参与缺氧诱导的一系列基因的表达调控。HIF-1在生物体的氧气供应、细胞代谢、心血管发育以及一系列疾病生理病理中起重要作用,其活性调节存在多种层次。HIF-1/HRE基因选择表达系统已被应用于基因治疗中。     

缺氧诱导因子-1在大鼠缺血性脑损伤中的双重作用

缺氧诱导因子-1(HIF-1)是低氧生理及病理过程中起作用的重要转录调控因子,由HIF-1α和HIF-1β两个亚单位组成。HIF-1调控的基因在能量代谢、红细胞生成、血管生成、血管扩张,细胞存活与凋亡中起一定作用。在大鼠缺血性脑损伤中,由于缺血时间和程度的不同,HIF-1对神经细胞具有保护和诱导凋亡的双重作用。它可以通过诱导靶基因如血管内皮细胞生长因子(VEGF)、促红细胞生成素(EPO)、葡萄糖转移蛋白-1(GLU-1)及葡萄糖合成酶的生成对缺血后脑细胞产生保护作用。然而,在严重缺氧条件下,HIF可以通过与肿瘤抑制蛋白p53结合、诱导bcl-2家族中的凋亡前基因BNIP3和NIX的表达以及促进诱导型一氧化氮合酶(iNOS)的生成而诱导细胞凋亡。特异性激活促进存活的基因或者抑制HIF-1的表达都可能成为临床治疗的策略。     

缺氧诱导因子-1在卵巢癌中的研究进展

恶性肿瘤的发生、发展与细胞的过度增殖有关,而肿瘤细胞增殖需大量耗氧。缺氧与肿瘤细胞的发生、侵袭、转移、对放、化疗的耐受性及预后等密切相关。缺氧诱导因子-1(hypoxia-inducible factor-1,HIF-1)是在缺氧条件下哺乳动物和人体内广泛存在的一种核转录因子,它通过诱导多种靶基因产物的表达,对维持肿瘤细胞的能量代谢、血管生成、无氧糖酵解以及促进肿瘤细胞的增殖和转移中起重要调控作用。侵袭和转移是卵巢癌的重要生物学特性之一,深入研究HIF-1在卵巢癌中的表达,有望为卵巢癌的治疗提供新的靶点。该文就HIF-1在卵巢癌中的研究进展作一综述。     

缺氧诱导因子-1转录活性的调控

缺氧诱导因子-1(hypoxia-inducible tactor 1,HIF-1)是缺氧活化的转录因子,在调节氧稳态、氧输送及肿瘤细胞的缺氧适应方面具有重要作用。HIF-1是由HIF-1α和HIF-1β组成的异源二聚体,HIF-1α为调节亚基。HIF-α的调节主要发生在转录后的蛋白修饰,包括羟化、乙酰化和磷酸化。另外,PI-3K/AKT信号通路也参与HIF-1转录活性的调节。研究HIF-1转录活性的调控对于深入了解肿瘤细胞耐受缺氧的分子机制具有重要意义。     

低氧诱导因子-1在调控骨骼肌缺氧时能量代谢发生适应性变化的机制研究进展

低氧诱导因子-1(HIF-1)是一种调控组织细胞氧稳态的关键性核转录因子,广泛存在于哺乳动物和人体内,其表达和活性受到细胞氧浓度的严密调控。它能在生理性和病理性缺氧缺血的情况下,通过调控细胞能量代谢、血管发生、红细胞生成、细胞生存、细胞增殖和凋亡等生物学效应,使细胞适应低氧环境得以生存或者走向凋亡。本文中我们主要概述了HIF-1的结构功能,及其在缺氧时调控骨骼肌能量代谢方面发生适应性变化的机制及研究进展。     

低氧诱导因子对缺氧缺糖诱导的心肌细胞损伤模型中自噬的调控作用

目的　探讨在缺血缺氧模型中低氧诱导因子（HIF-1α）对自噬相关基因Beclin1,LC3I,LC3II的影响及其对自噬的调节作用。 方法　建立缺血缺氧细胞模型,利用western blot 检测HIF-1α siRNA的干预效果;利用CCK-8实验检测HIF-1α siRNA对心肌细胞活性的影响;利用RT-qPCR与western blot检测HIF-1α siRNA对自噬相关基因Beclin1,LC3I,LC3II的影响。 结果　Western blot结果显示HIF-1α siRNA可有效敲低模型心肌细胞中HIF-1α的表达;CCK-8实验结果显示,HIF-1α siRNA可降低缺血缺氧细胞模型中心肌细胞的活性;RT-qPCR与western blot结果均提示HIF-1α siRNA可降低模型细胞中自噬相关基因Beclin1,LC3I,LC3II的表达,降低LC3II/LC3I的比率。 结论　HIF-1α siRNA敲低缺血缺氧细胞模型中的HIF-1α表达后,导致心肌细胞的活性进一步降低,细胞中Beclin1表达降低,LC3II/LC3I的比率降低,HIF-1α正调控缺血缺氧诱导的自噬而发挥心肌保护作用。     

Basic FGF augments hypoxia induced HIF-1-alpha expression and VEGF release in T47D breast cancer cells

AIM: Both hypoxia inducible factor 1 (HIF-1) and basic fibroblast growth factor (bFGF) play important roles in tumour angiogenesis. This study was designed to clarify the cooperative effect of these two mediators in induction of vascular endothelial cell growth factor (VEGF) release from breast cancer and probe possible mechanisms involved. METHODS: Release of VEGF from a breast cancer cell line (T47D) was quantitated by enzyme linked immunosorbent assay (ELISA). Expression of HIF-1 and ERK was assayed using Western blotting. Transient transfection and dual luciferase reporter assay were used to study HIF-1 transactivity. RESULTS: The data showed that hypoxia induced the expression of HIF-1alpha protein, the transactivity of HIF-1 and the release of VEGF. bFGF further augmented these hypoxic inductions. The PI3K pathway was required for these processes as demonstrated by application of PI3Kinase inhibitor (LY294002) or mutant construct transfections. In contrast, the MEK1 inhibitor PD98059 showed no effect on either activation of HIF-1 or VEGF release, which is in agreement with our finding that ERK1/2 was not activated by hypoxia. Under hypoxic conditions, bFGF activated the MEK1/ERK pathway. PD98059 blocked the activation of ERK1/2 and suppressed bFGF-induced HIF-1 transactivity, yet the protein expression of HIF-1alpha or VEGF release was not affected by PD98059. CONCLUSION: bFGF augments hypoxia induced VEGF release mainly through the PI3K pathway and partly depending on HIF-1 activity. Elucidation of this mechanism may provide a new target for anti-angiogenesis in cancer therapy.     

沉默HIF-1α基因表达对大鼠肝癌细胞增殖的影响

 目的： 探讨沉默缺氧诱导因子　1α（HIF-1α）基因表达对缺氧状态下肝癌细胞增殖的影响。方法：选用大鼠CBRH-7919肝癌细胞株作为研究对象,利用氯化钴（CoCl2）建立缺氧模型。制备3组特异性较强的HIF-1α siRNA-脂质体复合物,转染于肝癌细胞。利用real-time RT-PCR、Western blotting等方法分别检测肝癌细胞HIF-1α、血管内皮生长因子(VEGF)、p21和cyclin D1在mRNA和（或）蛋白水平的表达。MTT及BrdU 掺入实验检测细胞增殖的变化。结果：缺氧条件下,肝癌细胞的HIF-1α和VEGF mRNA及蛋白表达显著增多（P<0.05）。HIF-1α基因表达沉默后,HIF-1α、VEGF及cyclin D1 mRNA和（或）蛋白表达明显减少（P<0.05）,p21蛋白表达明显增加（P<0.05）。HIF-1α siRNA转染组的BrdU阳性细胞比例明显少于对照组(P<0.05)。结论：沉默HIF-1α基因表达对缺氧状态下肝癌细胞的增殖有显著抑制作用。     

Hypoxia-inducible factor 1 and VEGF upregulate CXCR4 in glioblastoma: implications for angiogenesis and glioma cell invasion

Hypoxia and hypoxia-inducible factor-1 (HIF-1) play a critical role in glioblastoma multiforme (GBMs). CXCR4 is involved in angiogenesis and is upregulated by HIF-1alpha. CXCR4 is a chemokine receptor for stromal cell-derived factor-1 (SDF-1)alpha, also known as CXCL12. We hypothesized that CXCR4 would be upregulated by hypoxia in GBMs. First, we investigated the expression of HIF-1alpha and CXCR4 in GBMs. CXCR4 was consistently found colocalized with HIF-1alpha expression in pseudopalisading glioma cells around areas of necrosis. In addition, angiogenic tumor vessels were strongly positive for CXCR4. Next, we tested the in vitro effect of hypoxia and vascular endothelial growth factor (VEGF) on the expression of CXCR4 in glioma cell lines and in human brain microvascular endothelial cells (HBMECs). Exposure to hypoxia induced significant expression of CXCR4 and HIF-1alpha in glioma cells, whereas treatment with exogenous VEGF increased CXCR4 expression in HBMECs. We also transfected U87MG glioma cells with an HIF-1alpha construct and observed that CXCR4 was upregulated in these cells even in normoxic conditions. We then used a lentivirus-mediated shRNA expression vector directed against HIF-1alpha. When exposed to hypoxia, infected cells failed to show HIF-1alpha and CXCR4 upregulation. We performed migration assays under normoxic and hypoxic conditions in the presence or absence of AMD3100, a CXCR4 inhibitor. There was a significant increase in the migration of U87MG and LN308 glioma cells in hypoxic conditions, which was inhibited in the presence of AMD3100. These studies demonstrate the critical role played by hypoxia and CXCR4 in glioma cell migration. Based on these studies, we suggest that hypoxia regulates CXCR4 in GBMs at two levels. First, through HIF-1alpha in the pseudopalisading tumor cells themselves and, secondly, by the VEGF-stimulated angiogenic response in HBMECs. We believe this knowledge may lead to a potentially important two-pronged therapy against GBM progression using chemotherapy targeting CXCR4.     

Correlation between VEGF and HIF-1alpha expression in human oral squamous cell carcinoma

Understanding the development and progression of oral cancer is critical in the quest for successful therapeutic intervention. The hypoxic microenvironment present in human oral tumor in vivo may actively influence tumor growth and neovascularization. This study correlates expression of both VEGF and HIF-1alpha in normal keratinocytes and oral cancer cell lines and determine whether hypoxia played a role in VEGF and HIF-1alpha regulation. Three human oral cancer cell lines and three normal keratinocytes were exposed to both normoxia and hypoxia culture conditions. Northern and Western blot analysis were used to assess VEGF and HIF-1alpha expression in the different culture conditions. ELISA assays were performed to measure VEGF production in the different cell lines tested. Hypoxia upregulated VEGF and HIF-1alpha expression on both normal and oral cancer cell lines, with a statistically significant difference between normal and oral cancer cell lines. Pattern of hypoxia-induced VEGF mRNA level tightly followed the HIF-1alpha mRNA expression in the cell lines tested. These results suggest that hypoxia regulates both VEGF and HIF-1alpha expression in head and neck carcinoma cell lines, thus establishing a biochemical pathway between tumor hypoxia and neoangiogenesis in these aggressive neoplasms.