脆性组氨酸三联体基因在宫颈癌前病变和宫颈癌中的表达及其与p53和HPV16/18的关系

目的 探讨脆性组氨酸三联体（FHIT）基因缺失与p53的过度表达和人乳头状瘤病毒16和（或）18（HPV16／18）感染在宫颈癌前病变（CIN）和宫颈癌（CC）发生发展中的作用和意义。方法 采用免疫组化SP法检测52例CIN和69例CC中的FHIT基因和p53的表达,以原位杂交方法检测HPV16／18感染情况,并以18例正常宫颈组织作为对照。结果 FHIT在正常宫颈组织（正常组）中呈阳性表达;FHIT在宫颈CIN组中的阴性率为30．8％,在CINⅢ期的表达,明显高于正常组和CINⅠ、Ⅱ期（P〈0．01）;在CC组中阴性率为66．7％（46／69）,明显高于正常组和CIN组（P〈0．01）,且随细胞分化的降低,FHIT阴性率上升。p53和HPV16／18在CC组的阳性率分别达56．5％（39／69）和84．1％（58／69）,均高于CIN和正常组（P〈0．05）,且CC组的p53阳性率随细胞分化的降低而升高（P〈0．01）。CIN和CC组的FHIT阳性和阴性者,p53阳性率差异均无统计学意义（P〉0．05）,相关性分析也显示无相关关系;但两组FHIT阴性者的HPV16／18感染率明显高于FHIT正常表达者（P〈0．01）,FHIT与HPV呈负相关关系。结论 FHIT基因缺失与宫颈癌发生有关,它在CIN中的缺失可能可作为高危型CIN人群的筛选和宫颈癌早期诊断指标。CIN和CC中的FHIT缺失常与p53过度表达同时存在,但两者间无相关性。HPV16／18可能是引起FHIT和p53异常的共同原因。     

Loss of heterozygosity and microsatellite instabilities of fragile histidine triad gene in gastric carcinoma

AIM: To detect the loss of heterozygosity (LOH) and microsatellite instabilities (MSI) of fragile histidine triad (FHIT) gene in gastric carcinoma and to study their association with the clinical pathological characteristics of gastric carcinoma. METHODS: LOH and MSI of FHIT gene were detected at four microsaterllite loci D3SI3H, D3S4I03, D3SI48I and D3S1234 using PCR in matched normal and cancerous tissues from 50 patients with primary gastric cancer. RESULTS: The average frequency of LOH and MSI of FHIT gene in gastric cancer was 32.4% and 26.4% respectively. LOH and MSI of FHIT gene in gastric cancer had no association with histological, Borrmann, and Lauren's classification. LOH of FHIT gene in gastric cancer was related to invasive depth. The frequency of FHIT LOH in gastric cancer with serosa-penetration was obviously higher than that in gastric cancer without serosa-penetration (73.5% vs 37.5%, P < 0.05). MSI of FHIT gene in gastric cancer was associated with the lymph node metastasis. The frequency of MSI in gastric cancer without lymph node metastasis was significantly higher than that in gastric cancer with lymph node metastasis (66.7% vs 34.3%, P < 0.05). CONCLUSION: LOH of FHIT gene is correlated with invasive depth of gastric carcinoma. MSI of FHIT gene is correlated with lymph node metastases. LOH and MSI of FHIT gene play an important role in carcinogenesis of gastric cancer.     

宫颈病变中FHIT基因微卫星不稳定性的研究

目的通过对宫颈病变中脆性组氨酸三联体(Fragile histidine traid,FHIT)基因上三个微卫星位点D3S1300、D3S1234和D3S1481的微卫星不稳定性(Microsatellite instability,MSI)分析,探讨其与宫颈癌的发生、发展的关系。方法采用聚合酶链反应-非变性聚丙烯酰胺凝胶电泳-溴化乙锭染色技术检测FHIT基因中3个微卫星位点D3S1300、D3S1234和D3S1481的MSI。结果 MSI在宫颈上皮内瘤样病变(Cervical intraepithelial neoplasia,CIN)组与宫颈癌组检出率差异有统计学意义。在宫颈癌中I期与II期差异无统计学意义,与III^IV期比较差异有统计学意义,MSI的发生率与临床分期有相关,与病理分级无关。结论 MSI在宫颈癌中的检出率远远高于CIN,表明MSI在宫颈癌发展过程中起重要作用,是宫颈癌恶性进展中的早期事件。     

Expression of WWOX and FHIT is downregulated by exposure to arsenite in human uroepithelial cells

Ecological studies in Taiwan, Chile, Argentina, Bangladesh, and Mexico have confirmed significant dose-dependent associations between ingestion of arsenic-contaminated drinking water and the risk of various human malignancies. The FHIT and WWOX genes are active in common fragile sites FRA3B and FRA16D, respectively. Reduced expression of FHIT or WWOX is known to be an early indicator of carcinogen-induced cancers. However, the effect of arsenite on the expressions and molecular mechanisms of these markers is still unclear. The aims of this study were (i) to observe the expression of ATR, WWOX and FHIT proteins in urothelial carcinoma (UC) between endemic and non-endemic areas of blackfoot disease (BFD) by immunohistochemical analyses; (ii) to compare expression of these genes between arsenite-treated SV-HUC-1 human epithelial cells and rat uroepithelial cells; and (iii) to determine the role of DNMT and MEK inhibitors on expressions of WWOX and FHIT in response to arsenite in SV-HUC-1. The experiments revealed that expressions of ATR, WWOX and FHIT in UC significantly differed between BFD areas and non-BFD areas (p = 0.003, 0.009 and 0.021, respectively). In fact, the results for the arsenite-treated groups showed that ATR, WWOX and FHIT are downregulated by arsenite in SV-HUC-1. However, the inhibitors suppressed the effects of arsenite on WWOX and FHIT proteins and mRNA expression. In conclusion, arsenite decreased expressions of ATR, WWOX and FHIT via ERK1/2 activation in SV-HUC-1 cells. These findings confirm that dysregulations of these markers may contribute to arsenite-induced carcinogenesis.     

FHIT基因与肺癌

肺癌中常发生3号染色体短臂(3p)的缺失,位于3p 14.2的FHIT基因是一种新的候选肿瘤抑制基因,它在肺癌发生机制中起一定作用。本文就FHIT基因结构特征,失活特点及其与肺癌的关系做一综述。     

FHIT基因在胃癌中的异常甲基化及其表达

目的:检测FHIT基因在胃癌中的异常甲基化及表达,探讨其在胃癌发生中的作用.方法:收集胃癌新鲜组织标本共88例,采用甲基化特异性PCR和免疫组织化学方法检测FHIT基因的异常甲基化和蛋白表达.结果:88例胃癌组织中,有35例发生了FHIT基因甲基化,阳性率为40%.55例表达FHIT蛋白,阳性率为63%.不同组织学分级的胃癌组织中甲基化率FHIT蛋白表达程度均有显著差异;淋巴结转移组织甲基化率、FHIT蛋白表达程度显著高于无转移者(P＜0.05).FHIT基因的异常甲基化和蛋白表达呈负相关(P＜0.01).结论:FHIT基因的异常甲基化和蛋白失表达是胃癌发生、发展过程中的频发事件,FHIT基因的异常甲基化可能是引起FHIT基因失活并导致胃癌发生的重要机制.     

散发性结直肠癌组织中FHIT、MSH2蛋白的异常表达及其临床意义

背景与目的:脆性组氨酸三联体(fragilehistidinetriad,FHIT)蛋白表达缺失是胃肠道肿瘤的频发事件,但在大肠癌却有争议;最近研究表明FHIT蛋白表达失活可能是错配修复蛋白,尤其是mutS同种组织蛋白2(mutShomolog2,MSH2)改变的结果。本研究旨在探讨FHIT、MSH2蛋白在散发性结直肠癌(sporadiccolorectalcarcinoma,SCC)组织中的表达情况及其临床意义。方法:采用免疫组化SP法检测手术切除的84例SCC及其对应癌旁正常结直肠组织和23例肠腺瘤组织标本中FHIT、MSH2蛋白的表达。结果:FHIT蛋白在SCC组织、结直肠腺瘤组织、癌旁正常结直肠组织中阳性率分别为48.81%、73.91%和100%,三者的阳性率差异有显著性(P<0.05)。FHIT蛋白表达水平与SCC患者的年龄、性别及肿瘤部位、组织学类型无关(P>0.05),而与肿瘤浸润深度、分化程度、Dukes分期和淋巴结转移有关(P<0.05),在浸润深度越深、分化程度越低、Dukes分期越晚和有淋巴结转移的癌组织中,FHIT蛋白低表达就越明显;而MSH2蛋白表达水平仅与Dukes分期有关(P<0.05)。SCC中FHIT蛋白表达与MSH2蛋白表达呈正相关(r=0.3728,P<0.01)。结论:(1)FHIT蛋白表达水平与SCC的恶性程度有关,可作为预测SCC浸润转移潜能的一项有意义的生物学指标;(2)SCC中FHIT、MSH2蛋白表达二者之间呈正相关。     

Identification of early target genes of aflatoxin B1 in human hepatocytes, inter-individual variability and comparison with other genotoxic compounds

Gene expression profiling has recently emerged as a promising approach to identify early target genes and discriminate genotoxic carcinogens from non-genotoxic carcinogens and non-carcinogens. However, early gene changes induced by genotoxic compounds in human liver remain largely unknown. Primary human hepatocytes and differentiated HepaRG cells were exposed to aflatoxin B1 (AFB1) that induces DNA damage following enzyme-mediated bioactivation. Gene expression profile changes induced by a 24 h exposure of these hepatocyte models to 0.05 and 0.25 μM AFB1 were analyzed by using oligonucleotide pangenomic microarrays. The main altered signaling pathway was the p53 pathway and related functions such as cell cycle, apoptosis and DNA repair. Direct involvement of the p53 protein in response to AFB1 was verified by using siRNA directed against p53. Among the 83 well-annotated genes commonly modulated in two pools of three human hepatocyte populations and HepaRG cells, several genes were identified as altered by AFB1 for the first time. In addition, a subset of 10 AFB1-altered genes, selected upon basis of their function or tumor suppressor role, was tested in four human hepatocyte populations and in response to other chemicals. Although they exhibited large variable inter-donor fold-changes, several of these genes, particularly FHIT, BCAS3 and SMYD3, were found to be altered by various direct and other indirect genotoxic compounds and unaffected by non-genotoxic compounds. Overall, this comprehensive analysis of early gene expression changes induced by AFB1 in human hepatocytes identified a gene subset that included several genes representing potential biomarkers of genotoxic compounds.     

子宫内膜病变组织中脆性组氨酸三联体基因的表达及临床研究

目的探讨脆性组氨酸三联体基因(FHIT)在子宫内膜癌及子宫内膜不典型增生组织中的表达及其与临床意义。方法以75例子宫内膜不典型增生及75例子宫内膜癌患者作为研究组,选取60例同期正常子宫内膜组织作为对照组,采用免疫组织化学(SP)方法,检测研究组与对照组中子宫内膜组织中FHIT的表达情况。并分析FHIT表达与子宫内膜癌病理分期、组织学分级的关系。结果正常子宫内膜、子宫内膜不典型增生、子宫内膜癌组织FHIT阳性表达率分别为96.67%、57.33%、34.67%(P<0.05)。高、中、低分化子宫内膜腺癌患者FHIT阳性表达率分别为61.54%、34.04%、13.33%,三者间有显著差异(P<0.05),Ⅰ期、Ⅱ期、Ⅲ期患者FHIT表达无显著差异。轻、中、重度子宫内膜不典型增生患者FHIT阳性率分别为64.71%、57.57%、52.00%。结论 FHIT作为1种肿瘤抑制基因蛋白,可能成为临床判断子宫内膜不典型增生预后转归的预测因素。