Terakado N, Shintani S, Nakahara Y, Mihara M, Tomizawa K, Suzuki K, Taniguchi N, Matsumura T
Department of Oral and Maxillofacial Surgery II, Okayama University Dental School, Okayama 700, Japan.
Oncol Rep. 2000 Sep-Oct;7(5):1113-7. doi: 10.3892/or.7.5.1113.
Radical scavengers play an important role in cancer cells defending themselves against free radicals which occur with irradiation. SOD (Cu,Zn, Mn-) and GST-pi are radical scavengers with an effect on radiation therapy. We investigated the correlation between radiation effects and expression of Cu,Zn-, Mn-SOD and GST-pi in 34 cases of oral cancer, treated with preoperative radiation therapy. In this study, 22 cases out of 34 were classified as effective and 12 cases as non-effective. Expression of Cu,Zn, Mn-SOD and GST-pi were observed in 13 (38.2%), 10 (29.4%) and 20 (58.8%) cases, respectively. Regarding the value of radiation sensitivity from expression of these proteins in the biopsy samples, no significant correlation was found between those expressions and histological effectiveness of preoperative radiation therapy. But interestingly, in 11 out of 12 of the non-effective cases, strong staining of Cu, Zn-SOD and GST-pi were shown at the residual cancer cells after preoperative radiation therapy. These results suggested that the expression of SOD (Cu,Zn-, and Mn-) and GST-pi may be not useful markers for predicting the effects of radiation therapy. However, Cu, Zn-SOD and GST-pi were increased by irradiation and may play an important role in radiation resistance and cancer cell regeneration after radiation therapy.
自由基清除剂在癌细胞抵御辐射产生的自由基过程中发挥着重要作用。超氧化物歧化酶（铜、锌、锰型）和谷胱甘肽S-转移酶π是对放射治疗有影响的自由基清除剂。我们研究了34例接受术前放射治疗的口腔癌患者的放射效应与铜、锌、锰型超氧化物歧化酶及谷胱甘肽S-转移酶π表达之间的相关性。本研究中，34例患者中有22例被归类为有效，12例为无效。铜、锌、锰型超氧化物歧化酶及谷胱甘肽S-转移酶π的表达分别在13例（38.2%）、10例（29.4%）和20例（58.8%）患者中观察到。关于活检样本中这些蛋白质表达的放射敏感性价值，未发现这些表达与术前放射治疗的组织学有效性之间存在显著相关性。但有趣的是，在12例无效病例中的11例中，术前放射治疗后残留癌细胞显示铜、锌型超氧化物歧化酶和谷胱甘肽S-转移酶π强染色。这些结果表明，超氧化物歧化酶（铜、锌、锰型）和谷胱甘肽S-转移酶π的表达可能不是预测放射治疗效果的有用标志物。然而，铜、锌型超氧化物歧化酶和谷胱甘肽S-转移酶π会因辐射而增加，可能在放射抗性和放射治疗后癌细胞再生中发挥重要作用。
