Development of a predictive assay for radiosensitivity of esophageal cancer

食道癌是放射治疗的一个具有挑战性的靶点。在本研究中，我们探讨了食道癌放射治疗反应的显著预测因素，并评价了细胞凋亡和免疫组织化学P53、Ki-67、c-erbB-2(HER-2/neu)、Ku(p70/p80)和DNA-PKcs在食管鳞癌放化疗疗效预测指标中的意义。本文回顾分析了34例食管鳞癌患者，治疗前均行肿瘤活检。在这些因素中，只有C-erbB-2/HER-2/neu癌蛋白表达显著(P=0.02)，但与生存无关。然后，为了增敏放射效应，我们观察了抗Her-2/neu抗体曲妥珠单抗对食管癌细胞株的增殖、细胞周期分布和放射敏感性的影响。流式细胞仪和免疫组化结果显示，2株食管癌细胞系HER-2/neu表达阳性，其余4株细胞系HER-2/neu阴性。单用曲妥珠单抗对HER-2/neu细胞株无明显影响，但10μg/ml曲妥珠单抗联合辐射对HER-2/neu表达的细胞有协同作用，进一步分析电离辐射后不同细胞系的转录变化，以确定其他与放射增敏有关的因素。在完成克隆存活分析后，我们选择了两个对辐射不同敏感的细胞系。随后，利用DNA微阵列技术对它们进行了研究，然后将上调的基因分为10组。在两种细胞系之间，DNA修复/复制类别的百分比差异最大，并且这一类别在辐射抗性细胞系中的比例更大

Esophageal carcinoma is a challenging target for radiation therapy. In this study, we investigated significant predictive factors for raido-responsiveness of the esophageal cancer.We evaluated the significance of apoptosis and immunohistochemical staining for p53,Ki-67,c-erbB-2(HER-2/neu),Ku(p70/p80) and DNA-PKcs for predictive markers of the responsiveness to chemoradiotherapy in esophageal squamous cell carcinoma. This retrospective analysis consist of 34 patients with esophageal squamous cell carcinoma in whom tumor biopsy was performed before treatment. Among these factors, only C-erbB-2/HER-2/neu oncoprotein expression was significant(P=0.02), though it did not correlate with survival.Then, to sensitize the radiation effect on the esophageal cells, we evaluated the effect of an anti-HER-2/neu antibody trastuzumab on the proliferation, cell cycle distribution, and radiosensitivity of esophageal cancer cell lines. Flow cytometry and IHC revealed that 2 esophageal cancer cell lines showed HER-2/neu expression, while other 4 esophageal cancer cell lines were negative. Although trastuzumab alone had no effect on the esophageal cancer cell lines, the combination of 10μg/ml trastuzumab with radiation showed a synergistic effect on the HER-2/neu expressing cell lines.We further analyzed transcriptional changes after ionizing radiation in different cell lines to identify other factors involving radiosensitivity. After completing clonogenic survival assays, we selected two cell lines with different radiosensitivities. Subsequently, they were investigated by using a technique of DNA microarray, and we then categorized the upregulated genes into 10 groups. Between the two cell lines, the difference in the percentage of DNA repair/replication category was the largest, and this category was present at a greater percentage with radioresistant cell line