Expression of c-myc protein is related to cell proliferation and expression of growth factor receptors in transitional cell bladder cancer

Archival biopsy specimens from transitional cell bladder tumours (n=185) were analysed immunohistochemically for expression of c-myc protein. The results were compared with compared with histopathological and clinical parameters and survival. Forty-three per cent of the tumours were negative for c-myc protein and weak, moderate, or strong cytoplasmic expression was found in 34, 14, and 9 per cent of cases, respectively. Nuclear positivity for c-myc protein was detected in 35 per cent of tumours and nuclear opositivity was related to overexpression of c-erb B-2 (P=0.01) and a high proportion of nuclei were also positive for p53 oncoprotein (p<0.05). Cytoplasmic expression of c-myc protein was related to histological grade (P=0.005), papillary status (P=0.007), the S-phase fraction (P=0.008), the mitotic index (P=0.021), overexpression of epidermal growth factor receptor (P=0.045), and c-erb B-2 (P=0.17). Expression of c-myc protein was not significantly related to the progression of tumours and it had no prognostic value in survival analysis. Independent predictors were the T-category (P<0.001), papillary status. (P=0.001), and S-phase fraction (P=0.061). The results show that while c-myc gene product participates in growth regulation of human bladder cancer cells, it has no independent prognostic significance.     

Expression of c-myc oncogene in coeliac disease.

A monoclonal antibody, produced by peptide immunisation was used to detect the distribution of p62c/myc by immunohistology in normal and coeliac small intestinal mucosa. The effect of gluten in four treated coeliac patients was investigated by taking serial jejunal biopsy specimens for six hours after a 10 g oral gluten challenge. There was a progressive increase in p62c/myc staining intensity in the villus enterocytes extending to the crypts, which accompanied the classical morphological changes occurring in the mucosa.     

PC12细胞缺糖损伤过程中凋亡相关基因的表达

目的探讨PC12细胞缺糖损伤时凋亡相关基因bcl-2、bcl-xl、c-myc的表达变化.方法无葡萄糖培养基培养PC12细胞建立细胞缺糖损伤细胞模型,用RT-PCR法分析PC12细胞有糖和无糖条件下bcl-2、bcl-xl、c-myc的表达情况.结果细胞缺糖损伤6-16hbcl-2基因、bcl-xl基因、c-myc基因表达量显著增高,此后表达量逐渐下降.结论缺糖损伤早期,凋亡抑制基因bcl-2、bcl-xl、c-myc上调表达产生细胞应激保护效应.     

Expression of c-myc in non-malignant and pre-malignant gastrointestinal disorders

A monoclonal antibody 1-6E10 against the protein product p62c-myc of the c-myc oncogene was used to assess, by immunohistology, a variety of non-neoplastic and preneoplastic disorders of gastric and colonic mucosa. There were low levels of expression of the c-myc oncogenic product in normal gastric and colonic tissue. In gastric mucosa, increased expression was observed with inflammatory, metaplastic and dysplastic histological appearances. In the normal colon low levels of expression were observed, but there was increased expression in inflammatory disorders including Crohn's disease and ulcerative colitis. There was also increased expression in colonic dysplasia associated with ulcerative colitis. The oncogene product was localized in the cytoplasm, nuclei and Golgi apparatus. C-myc 1-6E10 may therefore be used as a marker to identify the cellular proliferative response in gastric and colonic mucosa that is associated with inflammation as well as potentially neoplastic hyperproliferative states.     

Expression profiling of genes related to asthma exacerbations

Background Asthma is a chronic airway inflammatory disease; however, the molecular mechanisms that underlie asthma exacerbation are only partially understood.
Objective To identify gene expression signatures that reflect the acute exacerbation of asthma, we examined the differential expression of genes during asthma exacerbation and stable condition by using microarray analysis.
Methods The subjects were mite-sensitive asthmatic children and non-asthmatic control children. The children were divided into four groups (AE: asthma exacerbation, n =12; SA: stable asthma, n =11; IC: infected control, n =6; and NC: non-infected control, n =5). Total RNA was extracted from peripheral blood mononuclear cells and subjected to microarray analysis with Illumina Human Ref8 BeadChip arrays. Welch's t -test was performed to identify genes whose expression was altered during asthma exacerbation. Quantitative real-time RT-PCR was performed on samples collected from 43 asthmatic children and 11 control children to verify the microarray results.
Results The expression of 137/16 genes was significantly up/down-regulated during asthma exacerbation assessed by microarray analysis. Of the genes, 62 were also differentially expressed during upper respiratory infection. Many of the asthma exacerbation related genes were involved in defence responses and responses to external stimuli, but these associations disappeared after excluding the infection-related genes. Quantitative real-time RT-PCR confirmed that the genes related (S100A8 and GAS6) and unrelated to infections (CD200 and RBP7) were differentially expressed during asthma exacerbation ( P <0.01).
Conclusions Previously unidentified immune responses during asthma exacerbation may provide further clarification of the molecular mechanisms underlying asthma.     

Expression of the c-myc and Ca-ATPase genes in cardiac muscle during adaptation to repeated stress

In the course of adaptation to repeated stress, the expression of the proto-oncogene c-myc found to increase much more rapidly than that of the Ca-ATPase gene. It is suggested that an increase in the level of c-myc expression may activate the structural Ca-ATPase gene and possibly also the heat-shock proteins. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 2, pp. 124–126, February, 1994     

Comparison of three related methods to select T cell-presented sequences of protein antigens

A comparison of three methods to predict T cell-presented sequences within antigenic proteins led to the view that recurrent hydrophobic residues might nucleate excised peptides as alpha-helices against hydrophobic surfaces. Such helices could be protease-protected structures on their way to desetope binding. The compared methods were: the amphipathicity algorithm of DeLisi and Berzofsky [Proc. natn. Acad. Sci. U.S.A. 82, 7048-7052. (1985)] as modified by Margalit et al. [J. Immun. 138, 2213-2229. (1987)] the strip of-helix hydrophobicity algorithm (SOHHA) of Stille et al. [Molec. Immun. 24, 1021-1027. (1987)] and the motifs algorithm of Rothbard and Taylor [EMBO J. 7, 93-100. (1988)]. Correct prediction was defined at two levels of stringency: (1) the predicted sequence overlapped the experimentally reported sequence when the ratio of the intersection of both to the union of both greater than or equal to 0.5 or (2) the sequences touched when there was a non-empty intersection of both sequences. We determined the sensitivity (correct predictions/number of reported T cell-presented sequences) and efficiency (correct predictions/number of predictions) at each level of stringency. In terms of overlap, the SOHHA was more sensitive (0.43) than the amphipathicity (0.29) (not significant) and motifs (0.0, 0.0) (p less than 0.05) predictions and more efficient (0.35) than the amphipathicity (0.14) and motifs (0.0, 0.0) predictions. At the less stringent criterion touching, the amphipathicity method (0.71) was as sensitive as motif Rothbard-4 (0.79) and more sensitive than SOHHA (0.57) and motif Rothbard-5 (0.43). At that criterion, the SOHHA was more efficient (0.47) than the amphipathicity (0.36) and motifs (0.25, 0.40) methods. We hypothesize that the comparability of these approaches reflected the common, predominant influence of recurrent hydrophobicity in their predictions.     

肺腺癌中miRNA34a和c-myc的表达及意义

目的检测肺腺癌组织中miRNA34a,癌基因c-myc的表达,探讨两者之间的关系及意义。方法采用qRT-PCR法检测mRNA miRNA34a,Western blot、免疫组化法检测c-myc蛋白在正常肺组织、癌旁肺组织、肺腺癌以及转移癌组织中的表达。结果(1)miRNA34a在肺腺癌组织中呈低表达,低于癌旁和正常肺组织(P0.01),高于转移癌组织(P0.01)。c-myc在肺腺癌组织中呈高表达,高于癌旁和正常肺组织(P0.01),低于转移癌组织(P0.01)。miRNA34a及c-myc在癌旁组织和正常肺组织之间的表达差异有统计学意义(P0.05)。(2)病理类型:miRNA34a及c-myc在低分化和高分化肺腺癌之间的表达差异均无统计学意义(P0.05)。两者在转移癌与非转移肺腺癌组织中的表达差异有统计学意义(P0.05)。(3)预后分析:cmyc阳性组的肺腺癌患者生存率低于阴性组(P0.05),miRNA34a低表达组患者的生存时间明显低于高表达组,差异有统计学意义(P0.01)。结论肺腺癌组织中miRNA34a的表达与c-myc蛋白表达呈负相关。c-myc高表达miRNA34a低表达提示患者预后不良。     

eIF4E与c-myc在喉癌中的表达及相关性研究

目的：检测真核细胞翻译起始因子4E（eIF4E）与原癌基因c—myc蛋白在喉癌组织中的表达，探讨二者与喉癌的关系及其相互之间的内在关系。方法：采用Western blot法分析36例喉癌标本中肿瘤核心区、癌旁组织区（过渡区）及无肿瘤手术切缘（无癌区）eIF4E与c—myc基因蛋白的表达水平，并进行统计学分析。结果：eIF4E与c-myc在喉癌无癌区、过渡区、核心区的表达水平呈递增趋势；且二者之间密切相关。结论：过度表达的eIF4E与c—myc均可导致喉癌细胞恶性转化，且二者在喉癌组织中的表达具有相关性，可为喉癌的基因治疗提供一定的理论基础。     

Expression of the proto-oncogene c-myc in human stenotic aortocoronary bypass grafts.

Proliferation and differentiation of vascular smooth muscle cells (VSMC) are central events in vascular pathobiology and play a major role in the development of stenotic and restenotic lesions [15, 27]. The proto-oncogene c-myc and other early cell cycle-regulating genes have been implicated in the induction of cell proliferation and differentiation under diverse pathophysiological conditions [11, 13]. In the present study we analyzed c-myc mRNAexpression by indirect nonradioactive in situ hybridization technique (NISH) in human stenotic venous bypass grafts (n = 32) retrieved during re-do operations of coronary artery disease and compared the results with 28 native veins (vena saphena magna) from the same patients.

Stenotic bypass grafts showed enhanced c-myc expression located predominantly in VSMCin the media and neointima (severity score: ++–+++, 32/32 stenotic veins). In native veins we observed only low levels of – c-myc mRNA(severity score: +, 28/28 native veins), all signals were restricted to endothelial cells of either the innermost intimal layer or of the vasa vasorum.

Our in situ hybridization studies demonstrate enhanced mRNAexpression of the proto-oncogene c-myc in stenotic venous bypass grafts. These results suggest that – in analogy to other pathophysiological conditions – c-myc exerts essential regulatory functions in cellular events operative during the initiation and progression of venous bypass graft disease.     

Expression of bcl-2 oncoprotein in pituitary tumours: comparison with c-myc.

AIMS/BACKGROUND: Whereas the control of hormone secretion from pituitary adenomas has been studied in considerable detail, the molecular events underlying the development of these tumours are still poorly understood. Abnormalities of some oncogenes and tumour suppressor genes have been previously reported to occur at very low frequencies. The aim of the present study was to assess the possible expression of the bcl-2 oncoprotein and to compare it with that of c-myc in pituitary adenomas. METHODS: Monoclonal antibodies were used, along with microwave antigen retrieval and the avidin-biotin immunohistochemical method, to investigate expression of the oncoproteins bcl-2 and c-myc in 30 primary pituitary tumours from five broad diagnostic groups and in five normal pituitaries. RESULTS: Bcl-2 and c-myc immunoreactivities were detected in nine (30%) and eight (27%) tumour samples, respectively. Of the nine bcl-2 and eight c-myc positive tumours, seven were positive for both oncoproteins and included one of the four corticotrophinomas studied, four of seven prolactinomas, one of two somatotrophinomas, and one of four oncocytomas. All 13 null cell adenomas studied were negative for both bcl-2 and c-myc immunoreactivities. CONCLUSIONS: These results indicate that the bcl-2 and c-myc oncoproteins are expressed abnormally in over one quarter of pituitary tumours. Most these tumours co-expressed both oncoproteins. The genetic complementation of simultaneously deregulated bcl-2 and c-myc is implicated, through the regulation of apoptosis, in the pathogenesis of pituitary tumours.     

缺氧诱导大鼠肺动脉PDGF和c－myc基因表达增强

为了研究生长因子和原癌基因在缺氧所致肺血管结构重建中的作用，我们选用Ｗｉｓｔａｒ大鼠，置于低压仓内模拟海拔５０００米高度持续缺氧７天和１４天。与平原对照组相比，缺氧７天时肺动脉血小板源生长因子Ａ链（ＰＤＧＦ－Ａ）基因表达水平略有升高，而后有下降趋势；缺氧１４天时ＰＤＧＦ－Ｂ链３．５ｋｂｍＲＮＡ表达显著升高。点杂交结果显示：ｃ－ｍｙｃ原癌基因正常时表达水平很低。Ｎｏｒｔｈｅｒｎｂｌｏｔ可见缺氧７天时有２．２ｋｂｍＲＮＡ转录，缺氧１４天时其含量进一步增加为正常的６倍。结果表明，缺氧过程中，ＰＤＧＦ－Ａ链和Ｂ链是顺序表达的，其表达水平与缺氧性肺血管结构重组过程有一定相关。ＰＤＧＦ的促增殖作用是通过ｃ－ｍｙｃ基因产物实现的。     

hTERT、c-myc、Ki-67在肝癌组织中的表达及意义

目的:探讨端粒酶逆转录酶(hTERT)、c-myc、Ki-67与肝癌临床病理特征的关系以及3个因子之间的相互关系.方法:采用免疫组织化学方法检测37例肝癌组织、5例正常肝组织中hTERT和c-myc、Ki-67的表达,并进行对比研究.结果:肝癌组织中hTERT、c-myc、Ki-67阳性表达率明显高于正常肝脏组织,差异均具有统计学意义(P<0.05);hTERT、c-myc、Ki-67在肝癌组织中的表达强度均与年龄、性别、转移及肿瘤体积无关(P＞0.05),而三者表达强度均随肝癌组织学分化程度下降而明显增强;hTERT的表达强度分布与c-myc表达强度分布不相关;hTERT与 Ki-67的表达强度相关,随hTERT表达强度增加,Ki-67强度随之增加;c-myc与Ki-67的表达强度相关,随c-myc表达强度增加,Ki-67表达强度随之递增.结论:hTERT、c-myc、Ki-67的高表达在肝癌的发生发展过程中起重要作用;三者在肝癌组织中的表达关系密切.     

eShadow: a tool for comparing closely related sequences

Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human-to-primate or mouse-to-rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements.     

The allelic loss of chromosome 3p25 with c-myc gain is related to the development of clear-cell renal cell carcinoma

To explore the role of allelic losses at 3p25 and genetic alterations of chromosome 8, we investigated the relationships between genetic alterations in these chromosomal regions and clinicopathologic findings (such as tumor size and grade), by employing fluorescence in situ hybridization (FISH). Fifty Japanese clear-cell renal cell carcinomas (RCCs) were examined by dual-color FISH using cosmid DNA probes for 3p25.1-25.3 combined with probes for chromosome 3 centromere, 8p12, 8p21.1, 8p21.3, 8p22 and 8q24.12-24.13 (c-myc), and chromosome 8 centromere. Deletion at 3p25.1-25.3 was detected in 38 patients (76%), while 8p12 deletion, 8p21.1 deletion, 8p21.3 deletion, 8p22 deletion and c-myc gain were detected in 23 (46%), 25 (50%), 25 (50%), 25 (50%), and 20 patients (40%), respectively. There was a significant correlation between 8p21.1 deletion, 8p21.3 deletion and 8p21.1 deletion with c-myc gain and tumor grade (p = 0.04, 0.04 and 0.02, respectively). Deletions at 8p21.1 and 8p21.3 with 3p deletion were significantly related to tumor grade; the statistical significance was identical to that of sole 8p deletion with tumor grade. The deletion at 3p25.1-25.3 with c-myc gain showed a significant correlation with tumor size, indicating an association with tumor progression. Our results suggest that the allelic loss of chromosome 3p25 with c-myc gain is related to the development of clear-cell RCC.     

c-myc和p53蛋白在宫颈癌组织中的表达及临床意义

目的探讨c myc和p53蛋白在宫颈癌中表达的临床意义。方法采用免疫组化法检测51例正常宫颈、宫颈上皮内瘤样病变(CIN)和宫颈鳞癌中的c myc和p53蛋白的表达,并用TUNEL法检测细胞凋亡数。结果正常宫颈c myc和p53未见表达,宫颈鳞癌c myc和p53表达高于CIN(P<0.05)。宫颈鳞癌和CIN的TUNEL标记率均低于正常宫颈,宫颈鳞癌与CIN及正常组比较相差非常显著(P<0.01)。结论细胞凋亡可能与宫颈癌的形成过程有关,c myc和p53蛋白过度表达在宫颈癌的发生发展中起很重要的作用。     

Evolutionary conservation of genomic sequences related to the GGP1 gene encoding a yeast GPI-anchored glycoprotein

Summary The GGP1 gene encodes the only GPI-anchored glycoprotein (gp115) that has been purified todate in the budding yeast Saccharomyces cerevisiae. It is a single-copy gene whose deduced amino-acid sequence shares no significant homology to any other known protein. In this paper we report a Southern hybridization analysis of genomic DNA from different eukaryotic organisms to identify homologues of the GGP1 gene. We have analyzed DNA prepared from a unicellular green alga (Chlamydomonas eugametos), from two distantly related yeast species (Candida cylindracea and Schizosaccharomyces pombe), and from the common bean Phasoleus vulgaris. The moderate stringency of the experimental conditions and the high specificity of the probes used indicate that a single-copy of GGP1-related sequences exists in all these eukaryotic organisms. The chromosomal localization of the GGP1 gene in S. cerevisiae has also been determined.     

Expression and immunogenicity of proteins encoded by sequences specific to Mycobacterium avium subsp. paratuberculosis

The development of immunoassays specific for the diagnosis of Johne's disease in cattle requires antigens specific to Mycobacterium avium subsp. paratuberculosis. However, because of genetic similarity to other mycobacteria comprising the M. avium complex, no such antigens have been found. Through a comparative genomics approach, 21 potential coding sequences of M. avium subsp. paratuberculosis that are not represented in any other mycobacterial species tested (n = 9) were previously identified (J. P. Bannantine, E. Baechler, Q. Zhang, L. Li, and V. Kapur, J. Clin. Microbiol. 40:1303-1310, 2002). Here we describe the cloning, heterologous expression, and antigenic analysis of these M. avium subsp. paratuberculosis-specific sequences in Escherichia coli. Nucleotide sequences representing each unique predicted coding region were amplified and cloned into two different E. coli expression vectors encoding polyhistidine or maltose binding protein (MBP) affinity purification tags. All 21 of the MBP fusion proteins were successfully purified under denaturing conditions and were evaluated in immunoblotting studies with sera from rabbits and mice immunized with M. avium subsp. paratuberculosis. These studies showed that 5 of the 21 gene products are produced by M. avium subsp. paratuberculosis and are antigenic. Immunoblot analysis with a panel of sera from 9 healthy cattle and 10 cattle with clinical disease shows that the same five M. avium subsp. paratuberculosis proteins are also detected within the context of infection. Collectively, these studies have used a genomic approach to identify novel M. avium subsp. paratuberculosis antigens that are not present in any other mycobacteria. These findings may have a major impact on improved diagnostics for Johne's disease.     

流动力对细胞原癌基因c-fos和c-myc表达的影响

目的研究流体力对脑微血管内皮细胞原癌基因c-fos和c-nyc表达的影响,为探索微血管疾病机理提供一定实验依据.方法获取Wistar大鼠脑微血管进行细胞培养,在平行板流动小室中对所培养的细胞施加力学作用,并应用免役组织化学技术观察微血管内皮细胞原癌基因c-fos和c-myc的表达.结果不同的流动力对体外培养的大鼠脑微血管内皮细胞c-fos和c-myc蛋白表达产生了不同的影响.c-fos蛋白表达在静态时非常低,但在4dynes/cm2和10dynes/cm2的流体力的作用下可诱导c-fos蛋白水平迅速增加,尤其是10dynes/cm2的流体力,并随着时间的延长而增加,到1h时达到高峰,随后c-fos蛋白表达量出现下降,2.5h时接近基础水平.c-myc蛋白在静态时表达也非常低,经流体力作用后缓慢增多.结论流体力的大小会影响c-fos和c-myc的表达,血液的力学信号传入细胞内并引起细胞的一些应答,也印证了c-fos和c-myc是被血液流体力作用短暂上调的基因,流体力与内皮细胞生长、增殖、损伤也有直接关系.