Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea.
J Hepatol. 2011 Feb;54(2):328-39. doi: 10.1016/j.jhep.2010.06.045. Epub 2010 Sep 17.
BACKGROUND & AIMS: Human carbonyl reductase1 (CBR1) has been reported to protect cells against lipid peroxidation. Since human hepatocellular carcinoma (HCC) cells are under oxidative stress in hypoxic conditions, we tested if CBR1 is upregulated by hypoxia inducible factor (HIF)-1α, helps tumor growth under hypoxia, and renders chemoresistance to cisplatin and doxorubicin in HCC.
Luciferase, EMSA, and chromatin immunoprecipitation (ChIP) assays were performed to analyze whether HIF-1α transactivates CBR1 promoter. CBR1 overexpression, siRNA, and inhibitors were used to study the role of CBR1 in tumor survival under hypoxia and chemoresistance to cisplatin and doxorubicin in HCC. FACS and Western blot analysis for oxidative stress markers were performed to measure ROS. Immunohistochemistry (IHC) was performed to analyze CBR1 expression in 78 cases of HCC and 123 cases of colon cancer tissues.
The CBR1 promoter was activated by HIF-1α. CBR1 overexpression enhanced cell survival by decreasing oxidative stress under hypoxia, cisplatin, and doxorubicin treatment. CBR1-siRNA increased apoptosis via increasing oxidative stress. Combinational therapy of CBR1 inhibitors with cisplatin or doxorubicin enhanced cell death in HCC cells. IHC showed CBR1 overexpression in 56 (72%) out of 78 HCC and 88 (72%) out of 123 colon cancer cases.
Overexpressed CBR1 by HIF-1α plays important roles in tumor growth under hypoxia and chemoresistance to anticancer drugs. The inhibition of CBR1 by specific inhibitors enhances anticancer drug efficacy in HCC. Therefore, we concluded that CBR1 is a good molecular target for the development of anticancer drugs for HCC patients.
已报道人类细胞色素 P450 还原酶 1（CBR1）可保护细胞免受脂质过氧化。由于人类肝癌（HCC）细胞在缺氧条件下处于氧化应激状态，我们检测了 CBR1 是否由缺氧诱导因子（HIF）-1α上调，是否有助于肿瘤在缺氧下生长，并使 HCC 对顺铂和阿霉素产生耐药性。
进行荧光素酶、电泳迁移率变动分析（EMSA）和染色质免疫沉淀（ChIP）测定，以分析 HIF-1α是否可反式激活 CBR1 启动子。CBR1 过表达、siRNA 和抑制剂用于研究 CBR1 在缺氧下肿瘤存活和 HCC 对顺铂和阿霉素的耐药性中的作用。流式细胞术和 Western blot 分析用于测量氧化应激标志物以检测 ROS。免疫组织化学（IHC）用于分析 78 例 HCC 和 123 例结肠癌组织中 CBR1 的表达。
CBR1 启动子被 HIF-1α 激活。CBR1 过表达通过在缺氧、顺铂和阿霉素处理下降低氧化应激增强细胞存活。CBR1-siRNA 通过增加氧化应激增加细胞凋亡。CBR1 抑制剂与顺铂或阿霉素联合治疗增强 HCC 细胞的细胞死亡。IHC 显示 78 例 HCC 中有 56 例（72%）和 123 例结肠癌中有 88 例（72%）表达 CBR1 过表达。
HIF-1α 过表达的 CBR1 在缺氧下肿瘤生长和对抗癌药物的耐药性中发挥重要作用。特异性抑制剂抑制 CBR1 可增强 HCC 中抗癌药物的疗效。因此，我们得出结论，CBR1 是开发 HCC 患者抗癌药物的良好分子靶标。
