MicroRNA在卵巢癌诊疗中的作用

微小RNA(micro RNA,miRNA)是一类长度约为22个核苷酸的单链非编码RNA,参与调节体内基因的表达,通过诱导靶mRNA的降解达到沉默的目的.目前大量研究表明多种miRNA与卵巢癌的诊断、预后以及化疗药物耐药中起到重要作用.全文对miRNA在卵巢癌中的多种作用进行总结,为临床找寻新的分子标志物提供科学依据.     

CD133 Role in Oral Carcinogenesis

Objective: to investigate CD133 immunoexpression, cancer stem cells marker, in oral epithelial dysplasias (OEDs) and oral squamous cells carcinomas (OSCCs) and understandits possible involvement in the malignant transformation process of these lesions and to better elucidate their biological behavior. Material and methods: Tissue samples of 15 cases of OSCCs and 15 OEDs were subjected to CD133 antibody immunohistochemistry reactions. The analysis used quantitative parameters (number of immunostained cells regardless of immunostaining sublocations). Results: All samples of OSCCs and OEDs showed positive immunostaining, with no significant difference between these groups (p = 0.283). We did not observe statistical difference between the degree of dysplasia and the amount of CD133+ cells (p = 0.899). CD133 immunoexpression showed no association with the OEDs and OSCCs sites. It was observed that nuclear and cytoplasmic immunostaining was more evident with the progression of the malignant process. Conclusion: It is suggested that the CD133 cellular localization together with the histopathological criteria of OEDs classification can contribute to provide more concrete indications about the oral carcinogenesis process.     

MicroRNA:癌症诊治新靶点

MicroRNA（miRNA）是人类体内重要的转录后调控因子,参与细胞分化、增殖以及凋亡等多个细胞生物学过程。miRNA表达谱的变化与肿瘤的发生发展密切相关,miRNA既可以是癌基因,也可以是抑癌基因。肿瘤的主要生物学特征均涉及到miRNA表达水平的变化,尤其在肿瘤免疫逃逸中的变化十分复杂。循环miRNA是人类血液中一种表达极其稳定的miRNA,能够较准确地反映肿瘤的疾病状态,检测肿瘤患者体内异常的循环miRNA表达谱可能成为肿瘤临床诊断和预后判断的一种新手段。miRNA的检测手段主要包括Northern blotting、微阵列和qRT-PCR等传统方法,也包括二代测序等新兴技术。miRNA模拟物以及携带miRNA的脂质体等治疗方案已取得一定进展,但这些方法均有一定局限性使其无法在临床大规模开展应用。在克服当前的这些技术难点之后,miRNA检测有望进入临床,帮助建立新的肿瘤诊断和治疗方案。     

Role of Copper Accumulation in Spontaneous Renal Carcinogenesis in Long-Evans Cinnamon Rats

Spontaneous renal cell tumors in totals of 223 male and female Long-Evans Cinnamon (LEC) rats of 51–120 weeks old, 157 male F344 rats of 51–120 weeks old, and 14 male Long-Evans Agouti (LEA) rats of 51–70 weeks old were examined histologically. The incidences of renal cell tumors increased with age in male and female LEC rats, but no tumors developed in F344 or LEA rats. Dilated atypical tubules of the kidneys were observed at high incidence in aged LEC rats. Copper staining of LEC rat kidneys showed a positive reaction in proximal tubules of the cortex and the outer stripe of the medulla. The renal copper concentration of LEC rats reached a peak in the period of necrotizing hepatitis with renal tubular necrosis, and was higher than that in F344 rats for up to 106 weeks. In contrast, the renal iron concentration of LEC rats was lower than that in F344 rats except in the period of necrotizing hepatitis. Long-term treatment of LEC rats with d -penicillamine, a copper-chelating agent, inhibited accumulation of copper, but not iron, in the kidneys, and inhibited the development of karyomegaly of proximal tubules and dilated atypical tubules. These results suggest that persistent copper accumulation after toxic necrosis of tubules is the major cause of spontaneous renal carcinogenesis in LEC rats.     

MicroRNA expression profiling is a potential diagnostic tool for thyroid cancer

BACKGROUND:

Approximately 30% of fine‐needle aspiration (FNA) biopsies of thyroid nodules are indeterminate or nondiagnostic. Recent studies suggest microRNA (miRNA, miR) is differentially expressed in malignant tumors and may have a role in carcinogenesis, including thyroid cancer. The authors therefore tested the hypothesis that miRNA expression analysis would identify putative markers that could distinguish benign from malignant thyroid neoplasms that are often indeterminate on FNA biopsy.

METHODS:

A miRNA array was used to identify differentially expressed genes (5‐fold higher or lower) in pooled normal, malignant, and benign thyroid tissue samples. Real‐time quantitative polymerase chain reaction was used to confirm miRNA array expression data in 104 tissue samples (7 normal thyroid, 14 hyperplastic nodule, 12 follicular variant of papillary thyroid cancer, 8 papillary thyroid cancer, 15 follicular adenoma, 12 follicular carcinoma, 12 Hurthle cell adenoma, 20 Hurthle cell carcinoma, and 4 anaplastic carcinoma cases), and 125 indeterminate clinical FNA samples. The diagnostic accuracy of differentially expressed genes was determined by analyzing receiver operating characteristics.

RESULTS:

Ten miRNAs showed >5‐fold expression difference between benign and malignant thyroid neoplasms on miRNA array analysis. Four of the 10 miRNAs were validated to be significantly differentially expressed between benign and malignant thyroid neoplasms by quantitative polymerase chain reaction (P < .002): miR‐100, miR‐125b, miR‐138, and miR‐768‐3p were overexpressed in malignant samples of follicular origin (P < .001), and in Hurthle cell carcinoma samples alone (P < .01). Only miR‐125b was significantly overexpressed in follicular carcinoma samples (P < .05). The accuracy for distinguishing benign from malignant thyroid neoplasms was 79% overall, 98% for Hurthle cell neoplasms, and 71% for follicular neoplasms. The miR‐138 was overexpressed in the FNA samples (P = .04) that were malignant on final pathology with an accuracy of 75%.

CONCLUSIONS:

MicroRNA expression differs for normal, benign, and malignant thyroid tissue. Expression analysis of differentially expressed miRNA could help distinguish benign from malignant thyroid neoplasms that are indeterminate on thyroid FNA biopsy. Cancer 2011. © 2011 American Cancer Society.     

Carcinogenesis Risk Assessment of Chemicals Using Medium-term Carcinogenesis Bioassays

There is a pressing need for medium term models as alternatives for two year testing of environmental compounds for carcinogenicity and toxicity. Optimally these should be of short duration in vivo, readily performed in the laboratory without the need for specialist equipment, be based on a priori reasoning and scientific principles and use effective surrogates for malignancies. The two models developed in DIMS Institute of Medical Science, the medium-term liver carcinogenesis bioassay and the medium-term multi-organ carcinogenesis bioassay, fulfil these criteria and have the massive advantage of already being used for testing of large numbers of agents.     

大肠癌相关microRNA研究进展

microRNA(miRNA)是一种大小约22个核苷酸的非编码单链小RNA分子,参与细胞增殖、分化、凋亡等多种重要细胞活动的调控。近来研究发现miRNA具有癌基因或抑癌基因样作用,参与多种恶性肿瘤的演进,是肿瘤发生、发展过程中重要分子。目前已发现多种miRNAs在大肠癌组织及大肠癌细胞系中异常表达,一部分在癌细胞中较正常细胞表达明显下降如miR-143、miR-145、let-7、miR-34a等,一部分表达则升高如miR-31、miR-21等。体外试验中将miR-143、miR-145的前体导入大肠癌细胞中,可观察到癌细胞生长受到抑制,且呈剂量依赖性。miRNA表达谱与大肠癌的生物学行为和临床分期相关,如Ⅳ期大肠癌miR-31的表达水平明显较Ⅱ期升高。而大肠癌细胞系中miRNA表达谱与癌组织差别较大,由细胞系中得到miRNA表达谱可能不适于用来推断临床样本的相应表达谱。目前研究比较多的miRNAs如miR-143、miR-145、miR-34a、let-7a等,均有抑制细胞生长增殖的作用,它们在癌细胞中表达下降导致细胞过度生长增殖,可能参与大肠癌的发生。一些化疗药物能明显影响大肠癌细胞中miRNA的表达水平,如阿霉素可明显上调miR-34的表达水平,人们推测miRNA可能是一些化疗药物发挥抗肿瘤作用的重要分子。综上,阐明大肠癌相关miRNA的作用机制将可能丰富大肠癌的病因学及分子病理学理论,为大肠癌诊断治疗提供新策略和思路。     

Chemopreventive Role of Sulforaphane by Upholding the GSH Redox Cycle in Pre- and Post-initiation Phases of Experimental Lung Carcinogenesis

Sulforaphane (SFN) is a natural, biologically active compound extracted from cruciferous vegetables such asbroccoli and cabbage with anti-inflammatory and anti-cancer properties. The present study was carried to assesscytoprotective potential in alleviating oxidative stress, to influence the initiation and subsequent carcinogenesiscaused by benzo(a)pyrene [B(a)P] administration in the pre- and post-initiation phases of carcinogenesis in Swissalbino mice. Sulforaphane, supplemented orally at a dose of 9μmoles /mouse/day was found to greatly lessenthe damaging effects of B(a)P in mice by increasing the availability of reducing equivalents to fulfil the futileGSH redox cycle and replenish GSH biosynthesis, stabilizing the thiol status. Activity of superoxide dismutaseand catalase in native gel prove their differential activities in cancer induced and treated animals. SFN was alsofound to prevent formation of leaky membranes by boosting the antioxidant status leading to maintenance ofATPase activity in B(a)P treated animals. Histopathological analysis confirmed reduction of carcinogen-associatedmorphological changes in the lung tissue. The results suggest that SFN has potential as a chemopreventivephytochemical against B(a)P induced lung damage in the processes of carcinogenesis.     

The Role of Bone Fracture at the Site of Carcinogen Exposure on Nickel Carcinogenesis in the Soft Tissue

The influence upon nickel subsulfide (α-Ni₃S₂; Ni-SS)-induced carcinogenesis in the soft tissue of bone fracture at the site of Ni-SS exposure was studied using female Fischer rats. During the one year of the experiment, the group subjected to bone fracture exhibited the shortest tumor induction time and survival time, and a significantly higher metastatic rate. The present study may suggest a model for the metastasis of human soft tissue tumors.     

The Dietary Effect of Monoglucosyl-rutin on Azomethane-Induced Colon Carcinogenesis

The dietary effect of monoglucosyl-rutin (M-R), a flavonoid, on azoxymethane (AOM)-induced colon carcinogenesis ‍was investigated in two experiments with 5 week old, F344 male rats. In the first experiment (5 weeks study), effects ‍of MR on AOM (15 mg/kg body weight 3 times weekly)-induced formation of aberrant crypt foci (ACF) in five ‍groups were assessed. In this experiment, group 3 given 500 ppm M-R with AOM had a significantly smaller number ‍of ACF containing 4 or more aberrant crypts than group 1 with AOM alone, and groups 2 and 3 given 100 ppm or ‍500 ppm M-R respectively had significantly lower BrdU labeling indices in the epithelial cells of large bowel than ‍group 1. For the second experiment, rats were divided into 8 groups. Groups 1-5 were given AOM as in the first ‍experiment. Groups 2-5 were fed diets containing 100ppm or 500ppm M-R for 4 weeks in the initiation phase or 36 ‍weeks in the post-initiation phase. Group 6 was given 500ppm M-R throughout the experiment, and group 7 was ‍kept on the basal diet and served as a control. At the termination of the experiment (40 weeks after the start), groups ‍2-5 had significantly smaller numbers of positive cells with anti-proliferating cell nuclea antigen (PCNA) antibody ‍than group 1. Furthermore, group 5 treated with 500ppm M-R for 36 weeks demonstrated tendencies for decrease in ‍the incidence and multiplicity of colon tumors. These data suggest that M-R has the potential to inhibit AOMinduced ‍colon carcinogenesis.     

Angiogenesis in Transgenic Models of Multistep Carcinogenesis

The histopathology and the epidemiology of human cancers, as well as studies of animal models of tumorigenesis, have led to a widely accepted notion that multiple genetic and epigenetic changes have to accumulate for progression to malignancy. Formation of new blood vessels (tumor angiogenesis) has been recognized, in addition to proliferative capabilities and to the ability to down-modulate cell death (apoptosis), as essential for the progressive growth and expansion of solid tumors beyond microscopic sizes of about 1–2mm in diameter. Mice overexpressing activated forms of oncogenes or carrying targeted mutations in tumor suppressor genes have proven extremely useful for to linking the function of these genes with specific tumor processes; the interbreeding of these mice let us study the extent of cooperativity between different genetic lesions in disease progression, leading to a greater understanding of multi-stage nature of tumorigenesis.     

Bcl-w在肿瘤发生发展中的作用

Bcl-2家族在肿瘤的发生发展中具有重要作用并在很大程度上决定了肿瘤对放化疗的敏感性。研究表明Bcl-w在膀胱癌的发生发展过程中起到重要作用。文章从下游效应和上游调控两个方面对Bcl-w在肿瘤中的研究进展作一综述。     

微小RNA在乳腺癌转移及预后评估中的作用

微小RNA（miRNA）是近年来发现的一类内源性的、进化上高度保守的非编码单链小RNA,长度约为19~25个核苷酸,主要通过特异性识别并结合靶基因mRNA,抑制其翻译或者直接降解靶基因,在转录后水平调控基因表达。近来研究表明,miRNA在乳腺癌的侵袭和转移中发挥重要的作用,并有望成为乳腺癌预后评估的新型的潜在分子标志物。     

microRNA 在浆液性卵巢癌中的研究进展

卵巢癌是女性生殖系统最致命的恶性肿瘤,尽管在临床和基础研究中做了很多的努力,但是卵巢癌的整体存活率并无明显的改善。近年来,越来越多的研究表明,microRNA 的异常表达与上皮性卵巢癌的发生发展有着密切联系,很多的 microRNA 被证实可预测卵巢癌的预后和转移,因此 microRNA 可能成为诊断卵巢癌的新的肿瘤标记物,这将会给卵巢癌的诊治开辟新的途径,为卵巢癌患者带来一片曙光。     

The Effect of Interferon on Carcinogenesis by N-Ethyl-N'-nitro-N-nitrosoguanidine in the Duodenum of Mice

The inhibitory effect of murine interferon α/β (Mu-IFN) on the induction of adenocarcinoma of the duodenum in C57BL/6 mice given N-ethyl-N-nitro-N-nitrosoguanidine (ENNG) was examined. ENNG was given continuously in drinking water for 4 weeks and Mu-IFN was given intraperitoneally for 12 weeks. Then, the duodenal tumors of mice were examined stereomicroscopically and histologically. The level of IFN activity and natural killer (NK) activity were evaluated after an intraperitoneal single injection of Mu-IFN, and the level of NK activity was evaluated 2, 5 and 8 weeks after giving ENNG and Mu-IFN. In the mice given Mu-IFN, the incidence of duodenal tumors was significantly decreased ( P < 0.01), compared with that in mice given ENNG alone. Further, anti-asialo GM1 was given intraperitoneally every 5 days for 8 weeks to depress NK function and the incidence and size of duodenal tumors were examined. The results indicated that NK cells also have an important effect on the process of carcinogenesis. These data suggest that chemoprevention with IFN may be feasible.     

Asef蛋白在肿瘤发生中的作用

Asef是可与APC基因的Arm结构相结合的两种蛋白之一,APC-Asef复合体参与细胞形态学、细胞迁移和神经元功能的调节作用,其与肿瘤的发生、发展、侵袭和转移密切相关.全文就Asef蛋白在肿瘤中的作用作一综述.     

Overexpression of Cyclin D1 in Rat Esophageal Carcinogenesis Model

Overexpression of cyclin D1 in human esophageal carcinomas has been well documented. The aim of the present study was to assess the expression of cyclin D1 in different types of esophageal epithelial lesions induced by N -nitrosomethylbenzylamine (NMBA) in rats. A total of 30 rats received s.c.-injections, five times/week, of 1.0 mg/kg NMBA for a period of 5 weeks followed by the same dose once per week for another 10 weeks. An additional 15 rats were given saline and used as controls to provide normal epithelium. The tumor incidence was 100% at the termination point of 21 weeks. Seventeen rats (57%) showed nuclear staining for cyclin D1, with a great variation in the intensity, as demonstrated by using an immunohistochemical technique. The cyclin D1 positive indices were in the range of 0% to 60% of the individual cells. Negligible staining was observed for normal esophageal epithelium, with a minimal increase in hyperplastic and dysplastic lesions. A significant elevation of cyclin D1 levels was observed in tumors. However, no significant differences were found between papillomas and carcinomas. The immunohistochemical results were confirmed by western blotting analysis. Tumors, papillomas and carcinomas overexpressing cyclin D1 had elevated proliferating cell nuclear antigen (PCNA) indices (P<0.05). The correlation coefficient of overexpressions of PCNA and cyclin D1 was r =0.7 for papillomas, but only r =0.3 for carcinomas. The study thus provides strong evidence of relatively early Overexpression of cyclin D1 during tumorigenesis in the present rat esophageal model. Cyclin D1 expression is not simply a direct consequence of increase cell proliferation.     

MicroRNA在六种不同器官肿瘤细胞系中的差异表达

[目的]利用生物芯片技术分析microRNA（miRNA）在六种不同器官肿瘤细胞系中mi-croRNA（miRNA）的表达差异。[方法]将210个（206个miRNA,4个阳性对照）与已知人类和小鼠miRNA互补的序列作为探针,点于玻片上制备寡核苷酸芯片。提取肿瘤细胞（HeLa、MCF-7、A549、HT-29、ES-2、K562）的miRNA,用荧光染料Cy3标记,并与制备好的芯片杂交。用Sca-nArrayTMExpress1.0扫描仪扫描荧光信号,采用ScanArray3.0和Cluster3.0软件分析处理扫描结果。并用Northernblot和RT-PCR方法对芯片检测结果进行验证。[结果]芯片检测到在六种不同器官肿瘤细胞系中,发现115种miRNA存在差异,91种miRNA没有明显差异。其中,miR-21在六种肿瘤细胞表达水平均较高,miR-125b表达水平均较低,let-7在六种细胞系中表达水平较低。miR-17-5p和miR-20a呈集簇表达,在卵巢肿瘤ES-2细胞系中的表达水平高于其它细胞,乳腺肿瘤细胞系MCF-7和宫颈癌细胞系HeLa的miRNA的表达谱聚为一类。[结论]应用生物芯片技术检测细胞中miRNA的表达差异谱是可行的,miRNA可能参与肿瘤的发生发展。