Enhancement of 5-fluorouracil-induced in vitro and in vivo radiosensitization with MEK inhibition.
Enhancement of 5-fluorouracil-induced in vitro and in vivo radiosensitization with MEK inhibition.
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DOI：
10.1158/1078-0432.ccr-11-0358
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发表时间：
2011-08-01
期刊：
影响因子：
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通讯作者：
Citrin DE
中科院分区：
文献类型：
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作者：
Urick ME;Chung EJ;Shield WP 3rd;Gerber N;White A;Sowers A;Thetford A;Camphausen K;Mitchell J;Citrin DE
胃肠道癌经常表现出Ras/MAPK途径的突变激活，这与对电离辐射（IR）和化疗的抗性有关。同步放射治疗和5-氟尿嘧啶（5-FU）为基础的化疗通常用于治疗胃肠道恶性肿瘤。我们先前报道了司美替尼（一种MEK 1/2抑制剂）的放射增敏作用。本研究的目的是评价司美替尼是否能增强5-FU诱导的放射敏感性。使用司美替尼、5-FU和5-FU+司美替尼的预IR处理，用HT 29（结肠直肠）、HCT 116（结肠直肠）和MiaPaca-2（胰腺）细胞系进行克隆形成存活测定。使用四唑转化测定法测定细胞增殖。用免疫细胞化学分析有丝分裂灾难和DNA修复。流式细胞仪检测细胞周期和凋亡。使用生长延迟来确定5-FU+司美替尼对体内肿瘤放射敏感性的影响。与单独使用任一药物相比，5-FU+司美替尼的IR前治疗显著降低了克隆形成生存期。存活分数为0.1时，5-FU+司美替尼的剂量修饰因子分别为HT 29、HCT 116和MiaPaca-2的1.78、1.52和1.3。与单药治疗相比，无论治疗顺序如何，司美替尼+5-FU治疗均降低了细胞增殖。司美替尼治疗增强5-FU细胞毒性和5-FU介导的放射增敏作用，伴随有丝分裂灾难和凋亡增加，以及Stat 3磷酸化和生存素表达减少。在体内，5-FU+司美替尼+5Gy与5-FU+5Gy和司美替尼单独给药相比，观察到累加性生长延迟。这些数据表明，司美替尼可以与5-FU一起使用，以增强放射反应。
Gastrointestinal cancers frequently exhibit mutational activation of the Ras/MAPK pathway, which is implicated in resistance to ionizing radiation (IR) and chemotherapy. Concurrent radiotherapy and 5-fluorouracil (5-FU) based chemotherapy is commonly used for treatment of gastrointestinal malignancies. We previously reported radiosensitization with selumetinib, an inhibitor of MEK1/2. The purpose of the current study was to evaluate if selumetinib could enhance radiosensitivity induced by 5-FU. Clonogenic survival assays were performed with the HT29 (colorectal), HCT116 (colorectal) and MiaPaca-2 (pancreatic) cell lines using pre-IR treatment with selumetinib, 5-FU and 5-FU+selumetinib. Cell proliferation was determined using a tetrazolium conversion assay. Mitotic catastrophe and DNA repair were analyzed using immunocytochemistry. Flow cytometry was used to analyze cell cycle and apoptosis. Growth delay was used to determine effects of 5-FU+selumetinib on in vivo tumor radiosensitivity. Pre-IR treatment with 5-FU+selumetinib significantly decreased clonogenic survival compared to either agent alone. Dose modifying factors at a surviving fraction of 0.1 for 5-FU+selumetinib was 1.78, 1.52, and 1.3 for HT29, HCT116, and MiaPaca-2, respectively. Cell proliferation was decreased by treatment with selumetinib+5-FU as compared to single agent treatment regardless of treatment sequencing. Enhancement of 5-FU cytotoxicity and 5-FU mediated radiosensitization with selumetinib treatment was accompanied by an increase in mitotic catastrophe and apoptosis, and reductions in Stat3 phosphorylation and survivin expression. In vivo, an additive growth delay was observed with 5-FU+selumetinib+5Gy versus 5-FU+5Gy and selumetinib alone. These data suggest that selumetinib can be used with 5-FU to augment radiation response.