siRNA 或 chetomin 抑制人恶性神经胶质瘤细胞中的 HIF-1α：通过 CA9 表达对缺氧放射抵抗的影响及其监测。

HIF-1α inhibition by siRNA or chetomin in human malignant glioma cells: effects on hypoxic radioresistance and monitoring via CA9 expression.

机构信息

Department of Radiotherapy, Faculty of Medicine, Martin-Luther-University Halle-Wittenberg, Ernst-Grube-Straße 40, 06097 Halle, Saale, Germany.

出版信息

BMC Cancer. 2010 Nov 4;10:605. doi: 10.1186/1471-2407-10-605.

BACKGROUND

Hypoxia induces activation of the HIF-1 pathway and is an essential characteristic of malignant gliomas. Hypoxia has been linked to tumor progression, therapy resistance and poor prognosis. However, little is known about the impact of HIF-1α inhibition on radioresistance of malignant glioma.

METHODS

In this study, we investigated the effects of the inhibition of HIF-1α on cell survival and radiosensitivity in U251MG and U343MG glioma cells, using two different strategies. HIF-1α inhibition was achieved by siRNA targeting of HIF-1α or via chetomin, a disruptor of interactions between HIF-1α and p300. The inhibition of the HIF-1 pathway was monitored by quantitative real-time PCR and Western blot analyses of the expression levels of HIF-1α and CA9. CA9 expression was investigated as a potential indicator of the efficacy of HIF-1 inhibition and the resulting radiosensitivity of malignant glioma cell lines was determined by clonogenic assay after irradiation under normoxic (2-10 Gy) or hypoxic (2-15 Gy) conditions.

RESULTS

Although siRNA and chetomin show distinct modes of action, both attenuated the hypoxia-induced radioresistance of malignant glioma cell lines U251MG (DMF10: 1.35 and 1.18) and U343MG (DMF10: 1.78 and 1.48). However, siRNA and chetomin showed diverse effects on radiosensitivity under normoxic conditions in U251MG (DMF10: 0.86 and 1.35) and U343MG (DMF10: 1.33 and 1.02) cells.

CONCLUSIONS

Results from this in vitro study suggest that inhibition of HIF-1α is a promising strategy to sensitize human malignant gliomas to radiotherapy and that CA9 could serve as an indicator of effective HIF-1-related radiosensitization.

背景

缺氧诱导 HIF-1 通路的激活，是恶性神经胶质瘤的一个重要特征。缺氧与肿瘤的进展、治疗抵抗和预后不良有关。然而，关于 HIF-1α 抑制对恶性神经胶质瘤放射抵抗的影响知之甚少。

方法

在这项研究中，我们使用两种不同的策略，研究了抑制 HIF-1α 对 U251MG 和 U343MG 神经胶质瘤细胞的细胞存活和放射敏感性的影响。通过 HIF-1α 的 siRNA 靶向或 chetomin（一种破坏 HIF-1α 与 p300 相互作用的抑制剂）来抑制 HIF-1α。通过定量实时 PCR 和 Western blot 分析 HIF-1α 和 CA9 的表达水平来监测 HIF-1 通路的抑制情况。CA9 的表达被用作 HIF-1 抑制的疗效的潜在指标，并且通过在常氧（2-10Gy）或缺氧（2-15Gy）条件下照射后克隆形成测定来确定恶性神经胶质瘤细胞系的放射敏感性。

结果

尽管 siRNA 和 chetomin 表现出不同的作用模式，但它们都减弱了恶性神经胶质瘤细胞系 U251MG（DMF10：1.35 和 1.18）和 U343MG（DMF10：1.78 和 1.48）的缺氧诱导的放射抵抗。然而，siRNA 和 chetomin 在 U251MG（DMF10：0.86 和 1.35）和 U343MG（DMF10：1.33 和 1.02）细胞中在常氧条件下对放射敏感性具有不同的影响。