Tonotsuka Norio, Hosoi Yoshio, Miyazaki Shukichi, Miyata Go, Sugawara Ko, Mori Takahiro, Ouchi Noriaki, Satomi Susumu, Matsumoto Yoshihisa, Nakagawa Keiichi, Miyagawa Kiyoshi, Ono Tetsuya
Department of Radiation Research, Faculty of Medicine, Tohoku University, Sendai 980-8575, Japan.
Int J Mol Med. 2006 Sep;18(3):441-7.
Esophageal cancer tissues and adjacent normal mucosae in 13 patients with primary esophageal cancer were examined for quantitative differences in DNA-dependent protein kinase (DNA-PK) activity and for expressions of Ku70, Ku80 and DNA-PKcs proteins by Western blotting and immunohistochemistry. The tumor tissues showed higher DNA-PK activity than the normal mucosae. Protein levels of Ku70, Ku80 and DNA-PKcs correlated with DNA-PK activities in the tumor tissues. Immunohistochemical analysis revealed that Ku70, Ku80 and DNA-PKcs located predominantly in the nuclei in both the tumor tissues and normal mucosae. In the normal epithelium, Ku70, Ku80 and DNA-PKcs were expressed only in the nuclei of the basal cell layers and not in those of the lumenal cell layers. In the tumor tissues, the expressions of DNA-PK proteins showed intratumoral heterogeneity. The different portions in the same tumor showed different expression levels of DNA-PK proteins, and even each tumor cell showed different expression levels. These results suggest that cell differentiation and tumor progression affect cellular DNA-PK protein levels and its activity. Furthermore, the intratumoral heterogeneity of DNA-PK protein expression in esophageal cancer cells/ tissues also suggests the difficulty in prediction of radio- or chemo-sensitivity of the tumor through estimation of DNA-PK activity/protein levels in tumor specimens.
对13例原发性食管癌患者的食管癌组织及相邻正常黏膜进行检测，采用蛋白质免疫印迹法和免疫组织化学法检测DNA依赖蛋白激酶（DNA-PK）活性的定量差异以及Ku70、Ku80和DNA-PKcs蛋白的表达。肿瘤组织的DNA-PK活性高于正常黏膜。肿瘤组织中Ku70、Ku80和DNA-PKcs的蛋白水平与DNA-PK活性相关。免疫组织化学分析显示，Ku70、Ku80和DNA-PKcs主要位于肿瘤组织和正常黏膜的细胞核中。在正常上皮中，Ku70、Ku80和DNA-PKcs仅在基底细胞层的细胞核中表达，而不在腔面细胞层的细胞核中表达。在肿瘤组织中，DNA-PK蛋白的表达显示出瘤内异质性。同一肿瘤的不同部分显示出不同的DNA-PK蛋白表达水平，甚至每个肿瘤细胞的表达水平也不同。这些结果表明，细胞分化和肿瘤进展会影响细胞DNA-PK蛋白水平及其活性。此外，食管癌细胞/组织中DNA-PK蛋白表达的瘤内异质性也表明，通过估计肿瘤标本中的DNA-PK活性/蛋白水平来预测肿瘤的放射敏感性或化学敏感性存在困难。
