Monoclonal antibodies define differential ras gene expression in malignant and benign colonic diseases

DNAS of some human tumours can transform NIH 3T3 fibroblast cells, thus demonstrating the transforming potential of human ras genes (Hu-rasHa, Hu-rasKi, and Hu-rasN, respectively Harvey, Kirsten and neuroblastoma ras genes). Only a small percentage of a given type of human carcinoma, however, scores positive in this assay system. Activation of ras and subsequent transformation of NIH 3T3 cells are either by a point mutation in the ras gene or enhanced expression of the normal, or proto-onc, ras gene. If the transformation of a given human tumour involves the enhanced expression of the normal or cellular ras gene and the resulting gene product, the tumour DNA would probably score negative in the NIH 3T3 transfection assay. In human colon carcinoma, for example, lesions at position 12 of Hu-rasKi have been found. None of nine colon carcinomas obtained at biopsy, however, contain the ras lesion at this position, using a Hu-rasHa probe; one other colon carcinoma does appear to contain amplified proto-onc ras, and other colon carcinomas do have increased levels of ras RNA. There are at least three explanations for these observations. Either very few colon carcinomas contain point-mutated ras, the lesion in the majority of colon carcinomas is at a position other than 12 or ras activation in many colon carcinomas involves the enhanced expression of either the point-mutated or proto-onc form of a ras gene. We have now used monoclonal antibodies directed against a synthetic peptide reflecting sequences of the human T24 ras gene product to define ras p21 protein expression in a spectrum of colonic disease states. Immunohistochemical analyses of individual cells within tissue sections reveal differences in ras p21 expression in colon carcinomas compared with normal colonic epithelium, benign colon tumours and inflammatory or dysplastic colon lesions. Our data suggest that ras p21 expression is correlated with depth of carcinoma within the bowel wall, and is probably a relatively late event in colon carcinogenesis.     

光镊拉曼光谱技术检测结肠癌细胞的研究

使用激光光镊拉曼光谱分析系统,测量了结肠癌病人的3种不同细胞的拉曼光谱。实验结果显示结肠癌细胞和正常细胞的拉曼光谱有明显的差异,这种差异可以由1002cm^-1和1300cm^-1处的峰值参数来标示。与正常细胞比,结肠癌细胞在1350cm^-1,1458cm^-1,1576cm^-1,1662cm^-1处的强度增加,表明在结肠癌组织细胞中核酸含量增加。在1300cm^-1,1442cm^-1,1647cm^-1,1739cm^-1处的强度减小,表明在结肠癌组织中脂类的含量减少。     

结肠癌并梗阻的诊治

本文就1978～1988年间收治40例结肠癌并梗阻患者的诊断与治疗进行探讨。在诊断方面,本文分析了结肠癌梗阻的临床特点,提出钡灌肠造影检查是确诊结肠癌梗阻的主要措施。本文认为对结肠癌所致梗阻均应尽量施行Ⅰ期切除肿瘤,根据全身和局部条件决定Ⅰ期吻合或造瘘。本组40例,Ⅰ期切除25例,无手术死亡,Ⅰ期吻合21例,无吻合口瘘并发症,取得了满意的效果。本文还对结肠癌梗阻穿孔的治疗作了讨论。     

溃疡性结肠炎大鼠模型及其结肠电异常

目的　制作大鼠溃疡性结肠炎 (UC)模型 ,研究结肠电异常。方法　以二硝基氯苯法制作溃疡性结肠炎模型 ,埋藏电极记录结肠电。结果　造模大鼠结肠形成典型的溃疡 ,并发现其结肠电活动明显异常 ,具体表现为基本电节律 (BER)减慢及收缩性复合肌电 (CEC)的幅值显著降低 ,负载峰电的BER和CEC百分数明显减少     

成人乙状结肠冗长症的诊断和治疗

目的乙状结肠冗长症是导致成人便秘的主要原因之一，为提高对该病的诊治水平进行探讨、方法通过5a来收治的15a例成人乙状结肠冗长症的临床资料进行总结，结果术后随访1～5a，均获满意结果，结论成人乙状结肠冗长症的诊断主要靠钡剂灌肠，治疗上首选非手术疗法，无效时，可行乙状结肠部分切除术.     

三种癌裸鼠移植瘤肝脾转移的比较研究

摘要: 目的利用人卵巢癌、胃癌、结肠癌裸鼠移植瘤动物模型观察比较肝脾转移情况。方法分别将人卵巢癌、 胃癌、结肠癌实体瘤移植到裸鼠皮下,在建立人卵巢癌、胃癌、结肠癌裸鼠实体瘤模型的基础上,观察裸鼠实体瘤生 长速度、存活时间及肝脾转移病理形态学变化。结果人卵巢癌、胃癌、结肠癌实体瘤移植到裸鼠皮下,移植成瘤 率、肝转移率皆为100% ; 卵巢癌脾转移100% ; 胃癌脾转移62. 5% ; 结肠癌脾转移75% 。人卵巢癌裸鼠实体瘤生 长速度高于胃癌、结肠癌裸鼠实体瘤,且肝脾转移快,存活时间短; 三种癌裸鼠移植瘤肝脾转移病理形态均有差异。 结论建立的人卵巢癌、胃癌、结肠癌裸鼠移植瘤肝脾转移完整地再现了人卵巢癌、胃癌、结肠癌患者肝脾转移的 临床过程,为探讨人卵巢癌、胃癌、结肠癌肝脾转移生物学机制和抗转移提供参考,三种癌裸鼠移植瘤肝脾转移癌 均有差异。     

基于生物信息学方法分析GABRD基因在结肠癌中的表达及预后情况

采用生物信息学方法探讨GABRD基因在结肠癌样本中的表达及预后情况。通过UCSC XENA下载33种肿瘤类型和正常组织的RNA序列数据和相关临床数据,使用R软件分析GABRD基因在结肠癌样本中的表达,并筛选共表达基因,对其进行富集分析;分析GABRD基因对结肠癌患者生存及预后的影响,并建立预后列线图;构建GABRD基因的蛋白质-蛋白质相互作用(protein-proteininteraction, PPI)网络并筛选关键模块及枢纽基因,验证枢纽基因的生存及临床诊断价值。结果表明：GABRD基因在结肠癌样本中高表达并影响患者生存,筛选得到369个共表达基因,基因本体论(gene ontology, GO)功能富集发现其主要参与G蛋白偶联等生物学过程,京都基因与基因组百科全书(Kyoto encyclopedia of genes and genomes, KEGG)通路富集显示其主要参与AMPK等信号通路;构建出由51个节点和523个连接组成的PPI网络,筛选枢纽基因5个,其中2个显著影响生存,5个具有临床诊断价值。综上,GABRD基因在结肠癌样本中高表达,影响结肠癌患者生存及预后,可能...     

溃疡性结肠炎大鼠模型的结肠电及NO变化

目的制作大鼠溃疡性结肠炎(UC)模型,研究结肠电异常和一氧化氮(NO)变化。方法以二硝基氯苯法制作溃疡性结肠炎模型,埋藏电极记录结肠电,以标准对照比色法检测其大肠洗液一氧化氮产物亚硝酸盐(NOP)的浓度。结果造模大鼠结肠形成典型的溃疡,并发现其结肠电活动明显异常,具体表现为基本电节律(BER)减慢及收缩性复合肌电(CEC)的幅值显著降低,负载峰电的BER和CEC百分数明显减少,大肠洗液NOP浓度则显著升高,两者呈显著负相关。结论NO在溃疡性结肠炎的病理过程及结肠电改变中具有重要的作用。     

Loss of constitutional heterozygosity in colon carcinoma from patients with familial polyposis coli

Recent studies have suggested a critical role of specific gene loss in several embryonic tumours and certain adult cancers. In retinoblastoma, hemizygosity or homozygosity of a recessive mutant allele results in the loss of normal gene product, and this seems to cause the manifestation of the disorder. Familial polyposis coli (FPC) is a human autosomal dominant trait characterized by numerous adenomatous polyps of the colon and rectum, and a high incidence of colon carcinoma. Karyotype analyses have failed to detect specific deletion or translocation. We report the use of polymorphic DNA markers to look for the somatic loss of heterozygosity at specific loci. Investigation of 38 tumours from 25 FPC patients, and 20 sporadic colon carcinomas from 19 patients, revealed frequent occurrence of allele loss on chromosome 22, with some additional losses on chromosomes 5, 6, 12q and 15. The FPC gene-linked DNA probe C11p11 also detected frequent allele loss in both familial and sporadic colon carcinomas but not in benign adenomas. These results suggest the possible involvement of more than one chromosomal locus in the development of familial and sporadic colon carcinomas.     

Colorectal cancer, one entity or three

Understanding of the mechanism of colorectal carcinogenesis has been gaining momentum for some years on account of its high incidence and impact on the lives of individuals affected. Different genetic abnormalities have been found in colorectal cancers from different sites. For example, proximal colon cancer is usually related to the nucleotide instability pathway, as microsatellite instability (MSI). However, distal colon cancer is usually associated with specific chromosomal instability (CIN). The development of cancer at the rectum, though similar to that at the colon, displays its own unique features. These differences might be partially attributed to different embryological development and physiological circumstances. Environmental factors such as diet and alcohol intake also differ in their role in the development of tumors in the three segments, proximal colon, distal colon, and rectum. “Proximal shift” of colon cancer has been known for some time, and survival rates of colorectal cancer are higher when rectal cancers are excluded, both of which emphasize the three different segments of colorectal cancer and their different properties. Meanwhile, colonic and rectal cancers are distinctive therapeutic entities. The concept of three entities of colorectal cancer may be important in designing clinical trails or therapeutic strategies. However, the dispute about the inconsistency of data concerning the site-specific mechanism of colorectal carcinoma does exist, and more evidence about molecular events of carcinogenesis and targeted therapy needs to be collected to definitely confirm the conception.     

基于小波分析的结肠蠕动压力信号提取方法

为了获取纯净的结肠蠕动信号,提出了一种基于小波分析的结肠蠕动压力信号提取方法.其中,对结肠压力信号进行5层的小波分解,去除干扰信号后重构信号,进而获得结肠蠕动压力信号.同时,针对异常的结肠压力数据进行了验证实验.结果表明:所提出的方法对异常的结肠压力信号具有很好的抑制效果,并可以保留结肠蠕动压力信号的细节特征;与含突变信号的结肠蠕动压力信号相比,所提取的结肠蠕动压力信号的信噪比较高、均方误差较低.     

蠕动式微机器人结肠镜系统及模型

研制了一种新型的基于蚯蚓蠕动原理的内窥镜机器人,可用于微创无创肠道诊疗.机器人直径和长度分别为9.5和120 mm,由自行研制的直线电磁驱动器驱动.详细介绍了样机的结构、运动原理和控制系统,建立了与爬坡能力相关的力学模型,给出了有效牵引的数学条件表达式,并对表达式的有效性进行了试验验证.建立了在粘弹性肠道中的受力模型,研究了牵引效率、临界步距,并进行了离体肠道试验.该研究为机器人结肠镜的临床应用奠定了基础.     

Suppression of tumorigenicity in human colon carcinoma cells by introduction of normal chromosome 5 or 18.

Development of colon carcinomas can be associated with allelic deletions on several chromosomes, including 5q and 18q. The APC gene on 5q and the DCC gene on 18q have been identified as potential tumour suppressor genes, whose suppression contributes to colon carcinogenesis. To investigate the role of genes in these deleted regions, we have now introduced a single normal human chromosome into a human colon carcinoma cell line, COKFu, through microcell hybridization. Several clones of hybrid cells containing normal chromosome 5, and others containing normal chromosome 18, were obtained. The morphology of the hybrid cells was markedly altered: the hybrids with chromosome 5 exhibited a closely packed polygonal morphology, and the hybrid cells with chromosome 18 were flattened. The cloning efficiency of the hybrid cells in soft agar was reduced from 0.46 to 0% of that of the parental carcinoma cells, and the tumorigenicity of these hybrid cells in athymic nude mice was completely suppressed. The growth properties of the hybrid cells with chromosome 11 were not substantially changed. These results strongly suggest that the genes on normal chromosome 5 and 18 function as tumour suppressors in colon carcinogenesis.     

Unresponsiveness of colon cancer to BRAF(V600E) inhibition through feedback activation of EGFR

Inhibition of the BRAF(V600E) oncoprotein by the small-molecule drug PLX4032 (vemurafenib) is highly effective in the treatment of melanoma. However, colon cancer patients harbouring the same BRAF(V600E) oncogenic lesion have poor prognosis and show only a very limited response to this drug. To investigate the cause of the limited therapeutic effect of PLX4032 in BRAF(V600E) mutant colon tumours, here we performed an RNA-interference-based genetic screen in human cells to search for kinases whose knockdown synergizes with BRAF(V600E) inhibition. We report that blockade of the epidermal growth factor receptor (EGFR) shows strong synergy with BRAF(V600E) inhibition. We find in multiple BRAF(V600E) mutant colon cancers that inhibition of EGFR by the antibody drug cetuximab or the small-molecule drugs gefitinib or erlotinib is strongly synergistic with BRAF(V600E) inhibition, both in vitro and in vivo. Mechanistically, we find that BRAF(V600E) inhibition causes a rapid feedback activation of EGFR, which supports continued proliferation in the presence of BRAF(V600E) inhibition. Melanoma cells express low levels of EGFR and are therefore not subject to this feedback activation. Consistent with this, we find that ectopic expression of EGFR in melanoma cells is sufficient to cause resistance to PLX4032. Our data suggest that BRAF(V600E) mutant colon cancers (approximately 8-10% of all colon cancers), for which there are currently no targeted treatment options available, might benefit from combination therapy consisting of BRAF and EGFR inhibitors.     

硒诱导人结肠癌细胞凋亡的实验研究

目的探讨硒对体外培养的人结肠癌细胞凋亡影响作用.方法将不同浓度的亚硒酸钠(Na2SeO3)分别加入到接种有体外培养的人结肠癌细胞悬液的培养瓶中,于不同时间应用流式细胞仪检测细胞凋亡率结果显示Na2SeO3可诱导结肠癌细胞凋亡,且该作用与Na2SeO3浓度和作用时间有关.结论硒可能通过诱导肿瘤细胞凋亡而达到抗肿瘤的作用.     

Identification and expansion of human colon-cancer-initiating cells

Colon carcinoma is the second most common cause of death from cancer. The isolation and characterization of tumorigenic colon cancer cells may help to devise novel diagnostic and therapeutic procedures. Although there is increasing evidence that a rare population of undifferentiated cells is responsible for tumour formation and maintenance, this has not been explored for colorectal cancer. Here, we show that tumorigenic cells in colon cancer are included in the high-density CD133+ population, which accounts for about 2.5% of the tumour cells. Subcutaneous injection of colon cancer CD133+ cells readily reproduced the original tumour in immunodeficient mice, whereas CD133- cells did not form tumours. Such tumours were serially transplanted for several generations, in each of which we observed progressively faster tumour growth without significant phenotypic alterations. Unlike CD133- cells, CD133+ colon cancer cells grew exponentially for more than one year in vitro as undifferentiated tumour spheres in serum-free medium, maintaining the ability to engraft and reproduce the same morphological and antigenic pattern of the original tumour. We conclude that colorectal cancer is created and propagated by a small number of undifferentiated tumorigenic CD133+ cells, which should therefore be the target of future therapies.     

维药西帕依溃结安灌肠剂对细胞凋亡的影响及其抗溃疡性结肠炎机理

 为了揭示维吾尔医学特色药(维药)西帕依溃结安灌肠剂(KJA)在维吾尔医学中用于缓解、治疗溃疡性结肠炎(UC)和抗结肠癌作用及可能机理,选择Wistar大鼠分为正常组、模型组、美沙拉嗪组、KJA加美沙拉嗪组、KJA灌胃组和KJA灌肠组,除正常组外其他组采用DNCB复合乙酸诱导UC模型并实施相应干预。在干预第11,17,24天检测结肠组织形态学及组织病理学评分、结肠细胞凋亡率等指标,进行相同阶段组间及不同阶段组内比较。结果显示,KJA在体能通过改善结肠组织形态学和组织病理学异常改变,选择性诱导炎症细胞凋亡,减轻炎症反应来发挥缓解、治疗UC作用。美沙拉嗪和KJA在治疗UC不同阶段时期对细胞各期凋亡率调节机制可能有差异。其中美沙拉嗪加KJA灌肠治疗对晚期凋亡率效果优于单独使用美沙拉嗪。     

A human colon cancer cell capable of initiating tumour growth in immunodeficient mice

Colon cancer is one of the best-understood neoplasms from a genetic perspective, yet it remains the second most common cause of cancer-related death, indicating that some of its cancer cells are not eradicated by current therapies. What has yet to be established is whether every colon cancer cell possesses the potential to initiate and sustain tumour growth, or whether the tumour is hierarchically organized so that only a subset of cells--cancer stem cells--possess such potential. Here we use renal capsule transplantation in immunodeficient NOD/SCID mice to identify a human colon cancer-initiating cell (CC-IC). Purification experiments established that all CC-ICs were CD133+; the CD133- cells that comprised the majority of the tumour were unable to initiate tumour growth. We calculated by limiting dilution analysis that there was one CC-IC in 5.7 x 10(4) unfractionated tumour cells, whereas there was one CC-IC in 262 CD133+ cells, representing >200-fold enrichment. CC-ICs within the CD133+ population were able to maintain themselves as well as differentiate and re-establish tumour heterogeneity upon serial transplantation. The identification of colon cancer stem cells that are distinct from the bulk tumour cells provides strong support for the hierarchical organization of human colon cancer, and their existence suggests that for therapeutic strategies to be effective, they must target the cancer stem cells.