Showing papers by "Cancer Research UK published in 2002"

Germline mutations in FH predispose to dominantly inherited uterine fibroids, skin leiomyomata and papillary renal cell cancer.

Abstract: Uterine leiomyomata (fibroids) are common and clinically important tumors, but little is known about their etiology and pathogenesis. We previously mapped a gene that predisposes to multiple fibroids, cutaneous leiomyomata and renal cell carcinoma to chromosome 1q42.3-q43 (refs 4-6). Here we show, through a combination of mapping critical recombinants, identifying individuals with germline mutations and screening known and predicted transcripts, that this gene encodes fumarate hydratase, an enzyme of the tricarboxylic acid cycle. Leiomyomatosis-associated mutations are predicted to result in absent or truncated protein, or substitutions or deletions of highly conserved amino acids. Activity of fumarate hydratase is reduced in lymphoblastoid cells from individuals with leiomyomatosis. This enzyme acts as a tumor suppressor in familial leiomyomata, and its measured activity is very low or absent in tumors from individuals with leiomyomatosis. Mutations in FH also occur in the recessive condition fumarate hydratase deficiency, and some parents of people with this condition are susceptible to leiomyomata. Thus, heterozygous and homozygous or compound heterozygous mutants have very different clinical phenotypes. Our results provide clues to the pathogenesis of fibroids and emphasize the importance of mutations of housekeeping and mitochondrial proteins in the pathogenesis of common types of tumor.

A Human Genome Diversity Cell Line Panel

Abstract: A resource of 1064 cultured lymphoblastoid cell lines (LCLs) ([1][1]) from individuals in different world populations and corresponding milligram quantities of DNA is deposited at the Foundation Jean Dausset (CEPH) ([2][2]) in Paris. LCLs were collected from various laboratories by the Human Genome

Geographical Variation in the Penetrance of CDKN2A Mutations for Melanoma

Abstract: Background: Germline mutations in the CDKN2A gene, which encodes two proteins (p16INK4A and p14ARF), are the most common cause of inherited susceptibility to melanoma. We examined the penetrance of such mutations using data from eight groups from Europe, Australia and the United States that are part of The Melanoma Genetics Consortium Methods: We analyzed 80 families with documented CDKN2A mutations and multiple cases of cutaneous melanoma. We modeled penetrance for melanoma using a logistic regression model incorporating survival analysis. Hypothesis testing was based on likelihood ratio tests. Covariates included gender, alterations in p14APF protein, and population melanoma incidence rates. All statistical tests were two-sided. Results: The 80 analyzed families contained 402 melanoma patients, 320 of whom were tested for mutations and 291 were mutation carriers. We also tested 713 unaffected family members for mutations and 194 were carriers. Overall, CDKN2A mutation penetrance was estimated to be 0.30 (95% confidence interval (CI) = 0.12 to 0.62) by age 50 years and 0.67 (95% CI = 0.31 to 0.96) by age 80 years. Penetrance was not statistically significantly modified by gender or by whether the CDKN2A mutation altered p14ARF protein. However, there was a statistically significant effect of residing in a location with a high population incidence rate of melanoma (P = .003). By age 50 years CDKN2A mutation penetrance reached 0.13 in Europe, 0.50 in the United States, and 0.32 in Australia; by age 80 years it was 0.58 in Europe, 0.76 in the United States, and 0.91 in Australia. Conclusions: This study, which gives the most informed estimates of CDKN2A mutation penetrance available, indicates that the penetrance varies with melanoma population incidence rates. Thus, the same factors that affect population incidence of melanoma may also mediate CDKN2A penetrance.

A randomised, double blind, placebo controlled study of celecoxib, a selective cyclooxygenase 2 inhibitor, on duodenal polyposis in familial adenomatous polyposis.

Abstract: Background: Non-selective cyclooxygenase (COX) inhibitors (non-steroidal anti-inflammatory drugs) inhibit large bowel carcinogenesis in patients with familial adenomatous polyposis (FAP). Their role in the duodenum of these patients is less certain. The disease modifying activity of specific COX-2 inhibitors has not been explored in humans. Patients and methods: This was a randomised, double blind, placebo controlled study of celecoxib (100 mg twice daily (n=34) or 400 mg twice daily (n=32)) versus placebo (n=17), given orally twice daily for six months to patients with FAP. Efficacy was assessed qualitatively by blinded review of shuffled endoscopy videotapes comparing the extent of duodenal polyposis at entry and at six months and quantitatively by measurement of the percentage change in duodenal area covered by discrete and plaque-like adenomas from photographs of high and low density polyposis. Results: Shuffled and blinded video review showed a statistically significant effect of 400 mg twice daily celecoxib compared with placebo treatment (p=0.033) with all five independent observers scoring a beneficial effect. Overall, patients taking celecoxib 400 mg twice daily showed a 14.5% reduction in involved areas compared with a 1.4% for placebo (p=0.436). However, patients with clinically significant disease at baseline (greater than 5% covered by polyps) showed a 31% reduction in involved areas with celecoxib 400 mg twice daily compared with 8% on placebo (p=0.049). Conclusions: A panel of five endoscopists found a significant reduction in duodenal polyposis after six months of treatment with celecoxib 400 mg twice daily. COX-2 inhibition may help this otherwise untreatable condition.

Prostate cancer: embodied experience and perceptions of masculinity

Abstract: While some argue that gender differences, which refer to the social classification into 'masculine' and 'feminine', have their source in 'culture', others argue there is no need to have an absolute dichotomy between culture and nature, or between constructionist and anti-constructionist epistemologies. Although there has been much theorising about the body, until recently little attention has been paid to empirical evidence. This paper looks at the way in which prostate cancer and its treatment affects men's bodies, their roles and sense of masculinity. Interviews were conducted with 52 men, exploring their experiences of prostate cancer. Findings suggest that many men are reluctant to consult their doctors, because 'men don't cry', thus reinforcing the notion that 'masculinity' is a social construction. However, while the illness and the side effects of surgical and radiotherapy treatments sometimes led to impotence and incontinence, the treatments that involved hormones were reported to have an additional, sometimes profound effect on libido, energy, ability to work, body shape and competitiveness. These side effects reduced some men's sense of masculinity. We conclude that the physical body as well as culture should be considered when trying to explain what it means to be masculine, and how illness may affect men's sense of masculinity.

Mutational switch of an IL-6 response to an interferon-γ-like response

Abstract: Signaling through Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) is central to the responses to the majority of cytokines and some growth factors, including the interferons (IFNs) and the IL-6 family of cytokines. The biological responses to stimulation through the widely distributed IL-6 and IFN-γ receptors are, however, completely different. Remarkably, it is shown here that, in mouse embryo fibroblasts lacking STAT3, IL-6 mediates an IFN-γ-like response including prolonged activation of STAT1, the induction of multiple IFN-γ-inducible genes, the expression of class II MHC antigens, and an antiviral state. Normal cells exposed to IL-6 thus require a STAT3-dependent function(s) to down-regulate STAT1 activity and prevent an IFN-γ-like response. The data encourage the view that the very disparate IFN-γ and IL-6 JAK/receptor complexes mediate a common set of generic or “core” signals which are subject to STAT3-dependent modulation to provide IL-6 specificity. The switching of one cytokine response to one closely mimicking another as a result of the loss of a single signaling component has profound implications, for example, for the interpretation of the phenotypes of knockout mice and for the clinical use of inhibitors of signaling.

Baseline findings of the Italian multicenter randomized controlled trial of "once-only sigmoidoscopy"--SCORE

Abstract: A single sigmoidoscopy examination at aroundage 60 years has been proposed as a cost-effective strategy toprevent colorectal cancer. A multicenter randomized con-trolled trial, the SCORE trial, is in progress in Italy to esti-mate the impact of this strategy on colorectal cancer inci-dence and mortality and the duration of the protective effect.We present the baseline screening outcomes.

Sequential tethering of Golgins and catalysis of SNAREpin assembly by the vesicle-tethering protein p115.

Abstract: p115 tethers coat protein (COP)I vesicles to Golgi membranes. The acidic COOH-terminal domain of p115 links the Golgins, Giantin on COPI vesicles, to GM130 on Golgi membranes. We now show that a SNARE motif-related domain within p115 stimulates the specific assembly of endogenous Golgi SNAREpins containing the t-SNARE, syntaxin 5. p115 catalyzes the construction of a cognate GOS-28–syntaxin-5 (v-/t-SNARE) complex by first linking the SNAREs to promote their direct interaction. These events are essential for NSF-catalyzed reassembly of postmitotic Golgi vesicles and tubules into mature cisternae. Staging experiments reveal that the linking of Golgins precedes SNAREpin assembly. Thus, p115 coordinates sequential tethering and docking of COPI vesicles by first using long tethers (Golgins) and then short tethers (SNAREs).

Role of Rab5 in the Recruitment of hVps34/p150 to the Early Endosome

Abstract: PI 3-kinases are important regulators of endocytic trafficking. We have previously proposed a model in which the Rab5 GTPase recruits EEA1 to the early endosome both directly, by binding to EEA1, and indirectly, through the recruitment of the p150/hVps34 PI 3-kinase and the production of PI[3]P in the endosomal membrane. In this study we have examined this model in vivo. We find that both endogenous hVps34 and p150 are targeted to enlarged endosomal structures in cells expressing constitutively activated Rab5, where they are significantly colocalized with EEA1. Recombinant fragments of p150 disrupt the endosomal localization of EEA1, showing that p150 is required for EEA1 targeting. We further analyzed the mechanism of GTP-dependent Rab5-p150 binding, and showed the p150 HEAT and WD40 domains are required for binding, whereas deletion of the protein kinase domain increases binding to Rab5. Overexpression of constitutively active Rab5 caused a redistribution of epitope-tagged hVps34 and p150 to Rab5-positive endosomes. However, subcellular fractionation showed that this was not due to a significant recruitment of hVps34 or p150 from the cytosolic to the particulate fraction. These data suggest that the binding of Rab5 to the HEAT/WD40 domains of p150 is important in regulating the localization of hVps34/p150. However, Rab5 does not appear to act by directly recruiting p150/hVps34 complexes from the cytosol to the endosomal membrane.

Correcting for non-compliance bias in case-control studies to evaluate cancer screening programmes

Abstract: In the evaluation of uncontrolled service screening programmes for cancer, the case-control design is sometimes used, in which people who die from the disease in question are compared with live con ...

PI3K Blockade by Ad-PTEN Inhibits Invasion and Induces Apoptosis in Radial Growth Phase and Metastatic Melanoma Cells

Abstract: Melanoma is an aggressive tumor with a propensity to rapidly metastasize. The PTEN gene encodes a phosphatase with an unusual dual specificity for proteins and lipids. Mutations of PTEN have been found in various human cancers, including glioblastoma, prostate, breast, lung, and melanoma. Here we investigate in vitro the effects of blocking PI3K signaling using adenoviral-delivered PTEN (Ad-PTEN) in cell lines derived from both early- and late-stage melanoma. Ad-PTEN transduced melanoma cell lines or normal cells were assayed for cell death, apoptosis, gene expression, invasion and migration, and regulation of angiogenesis. The PTEN locus from RGP and metastatic melanoma cell lines was sequenced; no coding region mutations were found. Adenoviral transfer of PTEN into melanoma cells containing wild-type PTEN alleles led to tumor-specific apoptosis and growth inhibition, with coordinate inhibition of AKT phosphorylation. Ad-PTEN suppressed cell migration by metastatic melanoma cells with concomitant increase in the level of cell surface E-cadherin. Immunohistochemical and confocal analyses localized PTEN to the cytoplasm and demonstrated enrichment at the cell membrane. Ad-PTEN inhibited angiogenesis as demonstrated by the tube formation assay using human vascular endothelial cells. These studies indicate that Ad-PTEN can inhibit tumor cells via multiple mechanisms and has proapoptotic, anti-metastatic, and anti-angiogenic properties. Thus, PI3K blockade via Ad-PTEN may be a promising approach for the treatment of early- and late-stage melanoma, even in tumors that do not harbor PTEN mutations.

VEGF release is associated with reduced oxygen tensions in experimental inflammatory arthritis.

Abstract: Objective The contribution of local VEGF production and subsequent angiogenesis within the synovial membrane to the propagation of arthritis is unclear. The relationship between synovial oxygenation and blood flow in the development of arthritic disease is unknown. We have therefore measured oxygen levels and perfusion rates in the synovial space in a murine model of arthritis. Methods Arthritis was induced in DBA/1 mice by immunisation with type II collagen. Oxygen and perfusion levels were measured polarographically using silver needle microelectrodes within the knee joints prior to and 10 days after the onset of arthritis. In addition, synovial cells were isolated from knee joints of naive, pre-arthritic and arthritic mice. Results Onset of arthritis was associated with a marked reduction in synovial oxygen tensions (pO 2 ). The perfusion rates in naive and arthritic animals were not significantly different: in naive mice, the rate was 0.58 ′ 0.11 ml/min/g and in arthritic joints, 0.64 ′ 0.17 ml/min/g. Furthermore, synovial cells isolated from the knee joints of naive animals did not express mRNA for VEGF, but significant levels were detected in cells from non-arthritic mice immunised with collagen. The onset of arthritis was associated with expression of VEGF mRNA and protein, and correlated negatively with pO 2 levels. Conclusion These data demonstrate that decreases in intra-articular pO 2 occur in established arthritic conditions and may be the stimulus for local VEGF production. However, perfusion was not increased in arthritic animals and vascular density was unaltered, suggesting that the neovascularisation associated with inflammatory arthritis, is insufficient to restore oxygen homeostasis in the joint.

Comparative modelling: an essential methodology for protein structure prediction in the post-genomic era.

Abstract: The gap between the number of protein sequences and protein structures is increasing rapidly, exacerbated by the completion of numerous genome projects now flooding into public databases. To fill this gap, comparative protein modelling is widely considered the most accurate technique for predicting the three-dimensional shape of proteins. High-throughput, automatic protein modelling should considerably increase our access to protein structures other than those determined by experimental techniques such as X-ray crystallography and NMR (nuclear magnetic resonance) spectroscopy. The uses for these complete three-dimensional models are growing rapidly, ranging from guiding site-directed mutagenesis experiments to protein-protein interaction predictions. In recognition of this, a number of very useful comparative modelling servers have begun to emerge on the Web. Molecular biologists now have a powerful web-based toolkit to construct models, assess their accuracy, and use them to explain and predict experiments. There is, however, still much to do by those engaged in algorithmic development if comparative modelling is to compete on an equal footing with experimental protein structure determination techniques.

Microarray analysis of orthologous genes: conservation of the translational machinery across species at the sequence and expression level

Abstract: Background: Genome projects have provided a vast amount of sequence information. Sequence comparison between species helps to establish functional catalogues within organisms and to study how they are maintained and modified across phylogenetic groups during evolution. Microarray studies allow us to determine groups of genes with similar temporal regulation and perhaps also common regulatory upstream regions for binding of transcription factors. The integration of sequence and expression data is expected to refine our current annotations and provide some insight into the evolution of gene regulation across organisms. Results: We have investigated how well the protein subcellular localization and functional categories established from clustering of orthologous genes agree with gene-expression data in Saccharomyces cerevisiae. An increase in the resolution of biologically meaningful classes is observed upon the combination of experiments under different conditions. The functional categories deduced by sequence comparison approaches are, in general, preserved at the level of expression and can sometimes interact into larger co-regulated networks, such as the protein translation process. Differences and similarities in the expression between cytoplasmicmitochondrial and interspecies translation machineries complement evolutionary information from sequence similarity. Conclusions: Combination of several microarray experiments is a powerful tool for the identification of upstream regulatory motifs of yeast genes involved in protein synthesis. Comparison of these yeast co-regulated genes against the archaeal and bacterial operons indicates that the components of the protein translation process are conserved across organisms at the expression level with minor specific adaptations.