结肠腺癌与正常黏膜组织RP基因mRNA表达差异分析

目的:探讨结肠腺癌与正常黏膜组织中核糖体蛋白(Ribosomal protein,RP)基因mRNA的表达差异。方法:用基因表达系列分析(Serial analysis of gene expression,SAGE)方法对结肠腺癌组织及正常黏膜组织中核糖体蛋白基因mRNA的表达进行分析。结果:在结肠腺癌和正常黏膜组织中共出现了101种RP基因或RP类似基因的表达,其中有6种仅在正常黏膜中表达,有17种仅在腺癌中表达,41种RP基因在癌组织中表达明显升高。结论:在结肠腺癌和正常黏膜中均有多种RP基因表达,但两者之间存在明显差别。

结肠腺癌及正常黏膜mRNA表达谱的构建

目的构建结肠腺癌和正常黏膜基因的mRNA表达谱,探讨其表达差异,为进一步研究提供线索。方法用SAGE(Serial analysis of geneexpression)方法构建两者的mRNA表达文库,挑选一定数量克隆进行测序,结果用SAGE2000软件分析并进行比较。结果构建了同一患者结肠正常黏膜和腺癌的SAGE表达文库,软件分析分别获得标签7926和7672个。癌组织与正常黏膜组织及与国外先期构建的结肠腺癌SAGE文库相比较其高表达基因之间均存在明显的表达差异。结论 SAGE技术是构建mRNA表达谱的有效方法 ;结肠腺癌与正常黏膜高表达基因之间存在明显差别;中国人结肠腺癌的基因表达可能具有自身的特点。

长期炎症性结肠炎患者的结肠直肠不典型增生发生率低:荧光内镜检查结果

Background and Study Aim: Patients with long-standing in-flammatory bowel disease (IBD) have an increased risk of developing colonic dysplasias. Dysplastic changes in flat mucosa are likely to be missed by conventional colonoscopy. Endoscopic fluorescence imaging, using 5-aminolevulinic acid (5-ALA) as photosensitizer, has evolved as a new technique to differentiate between normal colonic mucosa and dysplasia. We combined this technique with random biopsies to prospectively evaluate the occurrence of dysplasias in patients with long-standing IBD. Patients and Methods: 52 colonoscopies were performed in 42 consecutive patients (n = 28 with ulcerative colitis, n = 11 with Crohn’s colitis, n = 3 with indeterminate colitis; mean age 43 years, range 21-78) with long-standing IBD colitis (median disease duration 14 years, range 3-40). All patients were in clinical remission. Patients were examined using both conventional white light and by fluorescence colonoscopy using oral 5-ALA. Four biopsies were taken every 10cm frommucosa of normal appearance. In addition, macroscopically suspicious and fluorescence-positive areas were biopsied. Results: A total of 688 biopsies of red-fluorescent (n = 20) and nonfluorescent (n = 662) areas of mucosa were taken. Dysplasia was detected histopathologically in only two of the biopsies. These biopsies were taken from two polypoid lesions which were fluorescence-negative. Conclusions: The rate of colonic dysplasia in patients with long-standing IBD colitis may be lower than previously reported.

缺损DNA错配修复决定一个近侧结肠癌特异的转录模式

Background & Aims: Colon cancers with defective DNA mismatch repair (MMR) have peculiar molecular, pathologic, and clinical features, including high-level microsatellite instability, conspicuous lymphocytic infiltration, preferential location in the proximal colon, and better prognosis. Our aim was to characterize the transcriptional profile of this colon cancer subset. Methods: An oligonucleotide microarray containing 12,625 probes was used to evaluate gene expression in 25 proximal colon cancers, 10 samples of normal colon mucosa, and 14 colon cancer cell lines. Transcriptional profiles of MMR-deficient cancers and cell lines were compared with those of their MMR-proficient counterparts. Results: Unsupervised anal-ysis of microarray data showed that MMR status exerts a predominant influence on the gene expression profile of proximal colon cancers. Hierarchical clustering divided the cancers into 2 groups corresponding almost perfectly with their MMR status. Supervised analysis identified numerous gene expression changes that represent a genetic signature of MMR-deficient colon cancers. Changes in genes involved in apoptosis and the immune response were consistent with the better prognosis of MMR-deficient cancers. In MMR-deficient cancers and cell lines, 4-1BBL, a crucial gene in the anti-tumor immune response, was, respectively, 2.4 and 6.0 times more expressed than in their MMR-proficient counterparts. This difference was con- firmed by quantitative reverse-transcription polymerase chain reaction and flow cytometric assessment of 4-1BBL protein expression in colon cancer cell lines. Our analysis also showed novel possible gene targets of microsatellite instability. Conclusions: MMR inactivation produces distinct changes in the cellular messenger RNA pool, which is consistent with a unique tumorigenesis pathway.

结肠直肠癌中Ⅰ、Ⅱ、Ⅲ、Ⅳ型乙醇脱氢酶同工酶和乙醛脱氢酶的活性

Chronic ethanol consumption is associated with an increased risk for cancer of the colorectum. The highly toxic and carcinogenic compound is acetaldehyde, the product of ethanol metabolism. Ethanol is metabolized to acetaldehyde by alcohol dehydrogenase (ADH) in colorectal mucosa and bacteria. The enzyme responsible for oxidation of acetaldehyde is aldehyde dehydrogenase. The aim of this study was to compare ADH isoenzymes and ALDH activity in colorectal cancer with the activity in normal colonic mucosa. Total ADH activity was measured by a photometric method with p-nitrosodimethylaniline(NDMA)as substrate, and ALDH activity by a fluorometric method with 6-methoxy-2-naphthaldehyde as a substrate. For measurement of the activity of class I and II isoenzymes we employed fluorometric methods,with class-specific fluorogenic substrates. The activity of class III ADH was measured by the photometric method with n-octanol as substrate, and class IV with m-nitrobenzaldehyde as substrate. Samples were taken surgically during routine operations of colorectal carcinomas from 32 patients. The activities of total ADH and, the most important in colon mucosa, class I ADH were significantly higher in cancer than in healthy tissues. The other tested classes of ADH had a tendency to higher-level activity in cancer cells than in healthy mucosa. ALDH activity was not significantly lower in the cancer cells. The activities of all tested enzymes and isoenzymes were not significantly higher in drinkers than in nondrinkers both in colorectal cancer and in normal mucosa.The differences in activities of total ADH and class I isoenzyme between cancer tissues and normal colon mucosa might be a factor for metabolic changes and disturbances in low-mature cancer cells and, additionally, might be a reason for the higher level of acetaldehyde, which can intensify carcinogenesis.

人结直肠癌黏膜下血小板源性内皮细胞生长因子特异性增强表达

PURPOSE: Platelet-derived endothelial cell growth factor, identified to be an angiogenic factor, has been implicated in metastases of colorectal cancer. This study aimed to clarify the role and localization of platelet-derived endothelial cell growth factor associated with human colorectal cancer invasion. METHODS: Thirty-two patients with colorectal cancer who had undergone surgery were analyzed. Platelet-derived endothelial cell growth factor enzyme activities in the colorectal cancer specimens were measured. Cells that expressed platelet-derived endothelial cell growth factor were identified and localized by immunohistochemical analysis with anti-human platelet-derived endothelial cell growth factor antibody and by in situ hybridization with specific RNA probe. RESULTS: Platelet-derived endothelial cell growth factor enzyme activity increased significantly in cancer tissues compared with normal colonic mucosa at various distances from the cancer. Immunohistochemical analysis and in situ hybridization demonstrated platelet-derived endothelial cell growth factor expression in stromal macrophages and fibroblasts located in cancer tissues and surrounding noncancerous tissues, although the tumor cells and normal colonic mucosa were negative. The value of platelet-derived endothelial cell growth factor expression was highest at the border of the colorectal cancer (35.3 ±8.9 percent), followed by the cancer nest (15.2 ±9.2 percent) and normal mucosa (7.7 ±3.4 percent). In the border area, the highest value of platelet-derived endothelial cell growth factor expressionwas observed in the submucosa (35.3 ±8.9 percent), followed by the muscular propria (21.9 ±7.7 percent) and the subserosa (14.9 ±5.5 percent). CONCLUSIONS: Stromal macrophages and fibroblasts are responsible for elevated platelet-derived endothelial cell growth factor activity in colorectal cancer. The significance of enhanced expression of plateletderived endothelial cell growth factor in the submucosa at the cancer border remains unclear. Cancer stroma may be an important factor for cancer angiogenesis and may serve as a treatment target through specific modulation of angiogenic factors.

遗传性混合型息肉综合征中环氧合酶-2的表达

Hereditary mixed polyposis syndrome (HMPS), characterized by hyperplastic, ju venile, admixed, serrated adenomas and eventually colorectal cancer, is managed by repeated polypectomy and surgery. We determined if HMPS polyps express cycloo xygenase- 2 (COX- 2). Nineteen recent HMPS polyps, from five family members, w ere stained for COX- 2. Polyps’ epithelium and stroma and comparison tissues (normal colonie mucosa [9], sporadic juvenile polyps [18], colorectal cancers [3 ]) were quantified for COX- 2 by: area of staining (0- 3) x intensity (0- 3). Epithelial, stromal, and total scores were evaluated in relationship to histolo gy and dysplasia. HMPS polyps COX- 2 mean epithelial (5.0 ± 3.0), stromal (6. 9 ± 1.9), and total (11.8 ± 4.6) scores were significantly higher (P < 0.01) than sporadic juvenile polyps (0.6 ± 0.7, 3.1 ± 2.2, and 3.6 ± 2.2 respec tively), while colorectal cancer scored 9, 9, and 18. There was a positive assoc iation (P < 0.01) among histology, degree of dysplasia, and COX- 2 expression. COX- 2 expression in HMPS polyps and its association with dysplasia suggest tha t chemoprevention might be a useful adjunct therapy.