Vaninetti Nadine M, Geldenhuys Laurette, Porter Geoffrey A, Risch Harvey, Hainaut Pierre, Guernsey Duane L, Casson Alan G
Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
Mol Carcinog. 2008 Apr;47(4):275-85. doi: 10.1002/mc.20382.
Nitric oxide (NO) has been implicated as a potential causative factor for endogenous p53 mutations in gastrointestinal malignancy. To investigate the role of NO in esophageal adenocarcinoma (EADC), we studied patterns of p53 mutations, expression of inducible nitric oxide synthase (iNOS) and the tissue accumulation of nitrotyrosine (NTS), a stable reaction product of NO and a marker for cellular protein damage, in human premalignant and malignant esophageal epithelia. Tissues were obtained from patients with gastroesophageal reflux disease (GERD)-induced esophagitis (n = 76), Barrett's esophagus (BE; n = 119) and primary EADC (n = 54). DNA sequencing was used to characterize p53 mutations, RT-PCR to study iNOS mRNA expression, and immunohistochemistry to study NTS. Relative to self-matched normal epithelia, a progressive increase in iNOS mRNA expression was seen in GERD (30%; 23/76), BE (48%; 57/119), and EADC (63%; 34/54) tissues (P < 0.001). Among patients with EADC, elevated levels of NTS immunoreactivity were more frequent in tumors with p53 mutations (11/21; 52%) compared with tumors with wild-type p53 (9/33; 27%; P = 0.063), and specifically in tumors with p53 mutations at CpG dinucleotides (10/12; 83%) compared with non-CpG p53 mutations (1/9; 11%; P = 0.008). The increasing frequency of iNOS (mRNA) overexpression in GERD, BE and EADC supports the hypothesis that an active inflammatory process, most likely a consequence of GERD, underlies molecular progression to EADC. The highly significant association between NTS, reflecting chronic NO-induced cellular protein damage, and endogenous p53 mutations at CpG dinucleotides, provides further evidence for a molecular link between chronic inflammation and esophageal malignancy.
一氧化氮（NO）被认为是胃肠道恶性肿瘤中内源性p53突变的一个潜在致病因素。为了研究NO在食管腺癌（EADC）中的作用，我们研究了人癌前和恶性食管上皮中p53突变模式、诱导型一氧化氮合酶（iNOS）的表达以及硝基酪氨酸（NTS）的组织积累情况，NTS是NO的一种稳定反应产物，也是细胞蛋白损伤的标志物。组织取自患有胃食管反流病（GERD）所致食管炎的患者（n = 76）、巴雷特食管（BE；n = 119）和原发性EADC患者（n = 54）。DNA测序用于鉴定p53突变，逆转录聚合酶链反应（RT-PCR）用于研究iNOS mRNA表达，免疫组织化学用于研究NTS。相对于自身匹配的正常上皮，GERD（30%；23/76）、BE（48%；57/119）和EADC（63%；34/54）组织中iNOS mRNA表达呈逐渐增加趋势（P < 0.001）。在EADC患者中，与野生型p53肿瘤（9/33；27%）相比（P = 0.063），p53突变肿瘤中NTS免疫反应性升高更为常见（11/21；52%），特别是与非CpG p53突变肿瘤（1/9；11%）相比（P = 0.008），CpG二核苷酸处p53突变肿瘤中NTS免疫反应性升高更为常见（10/12；83%）。GERD、BE和EADC中iNOS（mRNA）过表达频率的增加支持了这样一种假说，即活跃的炎症过程，很可能是GERD的结果，是向EADC分子进展的基础。反映慢性NO诱导的细胞蛋白损伤的NTS与CpG二核苷酸处的内源性p53突变之间高度显著的关联，为慢性炎症与食管恶性肿瘤之间的分子联系提供了进一步的证据。
