Journals
2009 EN
Krahn Martin · Béroud Christophe · Labelle Véronique
+20 more
Dysferlinopathies belong to the heterogeneous group of autosomal recessive muscular dystrophies. Mutations in the gene encoding dysferlin ( DYSF ) lead to distinct phenotypes, mainly Limb Girdle Muscular Dystrophy type 2B (LGMD2B) and Miyoshi myopathy (MM). Here, we analysed the mutational data from the largest cohort described to date, a cohort of 134 patients, included based on clinical suspicion of primary dysferlinopathy and/or dysferlin protein deficiency identified on muscle biopsy samples. Data were compiled from 38 patients previously screened for mutations in our laboratory (Nguyen, et al., 2005; Nguyen, et al., 2007), and 96 supplementary patients screened for DYSF mutations using genomic DHPLC analysis, and subsequent sequencing of detected variants, in a routine diagnostic setting. In 89 (66%) out of 134 patients, molecular analysis identified two disease causing mutations, confirming the diagnosis of primary Dysferlinopathy on a genetic basis. Furthermore, one mutation was identified in 30 patients, without identification of a second deleterious allele. We are currently developing complementary analysis for patients in whom only one or no disease‐causing allele could be identified using the genomic screening procedure. Altogether, 64 novel mutations have been identified in this cohort, which corresponds to approximately 25% of all DYSF mutations reported to date. The mutational spectrum of this cohort significantly shows a higher proportion of nonsense mutations, but a lower proportion of deleterious missense changes as compared to previous series. © 2008 Wiley‐Liss, Inc.
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Journals
2009 EN
Valdmanis Paul N. · Verlaan Dominique J. · Rouleau Guy A.
As more studies are turning to bioinformatic prediction programs to assess the potential impact of amino acid substitutions, it is relevant to evaluate the prediction results these programs give in genes that have been well‐characterized for Mendelian diseases. Eight genes responsible for neurodegenerative disease with many identified mutations were sub‐grouped into those that either have a gain or loss of function disease mechanism. Three prediction programs, PolyPhen, Panther and SIFT, were queried for the reported missense mutations. The mean percent of benign mutations was significantly higher in gain of function genes using the PolyPhen program (38% versus 21%, p=0.007). The probability that a gain of function mutation was predicted to have a damaging role was also significantly less using the Panther program (p=4.86x10 −12 ). In contrast, there was no difference between gain and loss of function gene when the SIFT program was used. However, the most accurate distinction between gain and loss of function genes could be obtained when considering the mutations for which all three programs predicted the same result. Further, stratification of SOD1 mutations indicated that only the PolyPhen program could distinguish mutations that impaired enzymatic activity of SOD1 from those with near wildtype activity. The profile of benign and damaging changes from these genes will aid in the interpretation of bioinformatic prediction program results from missense mutations identified in novel genes. © 2008 Wiley‐Liss, Inc.
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Journals
2009 EN
RoveletLecrux Anne · Lecourtois Magalie · ThomasAnterion Catherine
+5 more
A heterozygous genomic deletion removing exons 6 to 9 of the microtubule associated protein tau (MAPT) gene, predicting to result into a truncated protein lacking the first microtubule binding domain, was detected in a patient with frontotemporal dementia (FTD). Cell culture experiments showed that the truncated tau isoforms had a dramatic decrease in the normal binding to microtubules but acquired the ability to bind microtubule associated protein‐1B (MAP‐1B). This indicates that this tauopathy likely results both from a loss of function mechanism and from a deleterious gain of function by which cytoplasmic deleted forms of tau sequester another MAP. Both mechanisms could contribute to impair microtubule dynamics. © 2009 Wiley‐Liss, Inc.
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Journals
2009 EN
Ferré Marc · Bonneau Dominique · Milea Dan
+14 more
We report the results of molecular screening in 980 patients carried out as part of their work‐up for suspected hereditary optic neuropathies. All the patients were investigated for Leber's hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA), by searching for the ten primary LHON‐causing mtDNA mutations and examining the entire coding sequences of the OPA1 and OPA3 genes, the two genes currently identified in ADOA. Molecular defects were identified in 440 patients (45% of screened patients). Among these, 295 patients (67%) had an OPA1 mutation, 131 patients (30%) had an mtDNA mutation, and 14 patients (3%), belonging to three unrelated families, had an OPA3 mutation. Interestingly, OPA1 mutations were found in 157 (40%) of the 392 apparently sporadic cases of optic atrophy. The e OPA1 locus‐specific database now contains a total of 204 OPA1 mutations, including 77 novel OPA1 mutations reported here. The statistical analysis of this large set of mutations has led us to propose a diagnostic strategy that should help with the molecular work‐up of optic neuropathies. Our results highlight the importance of investigating LHON‐causing mtDNA mutations as well as OPA1 and OPA3 mutations in cases of suspected hereditary optic neuropathy, even in absence of a family history of the disease. © 2009 Wiley‐Liss, Inc.
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Journals
2009 EN
Colin Didier · Gimazane Amandine · Lizard Gérard
+4 more
Epidemiological studies suggested that trans ‐resveratrol, a wine grape component, could prevent malignant tumor development. This compound also demonstrated cytostatic and cytotoxic effects on tumor cells in vitro . To obtain trans ‐resveratrol derivatives with a better cellular uptake and enhanced antiproliferative effects, we synthesized a triacetate derivative as well as an oligomer, ε‐viniferin and its acetylated form, ε‐viniferin penta‐acetate. We also obtained vineatrol, a wine grape shoot extract that associates several polyphenols that may act synergistically, including trans ‐resveratrol and ε‐viniferin. We show here that resveratrol triacetate and vineatrol are as efficient as trans ‐resveratrol in inducing the accumulation of human colon cancer cells in early S phase of the cell cycle. This effect is associated with a nuclear redistribution of cyclin A and the formation of a cyclin A/cyclin‐dependent kinase 2 complex whose kinase activity is increased. In contrast, ε‐viniferin and its acetylated form do not demonstrate any significant activity on these cells when tested alone. Interestingly, resveratrol triacetate and vineatrol dramatically enhance 5‐Fluoro‐Uracil‐mediated inhibition of colon cancer cell proliferation. Thus, acetylated derivatives of resveratrol have retained the cytostatic and cytotoxic activities of the parental molecule and thus deserve to be tested as chemosensitizers in animal models. © 2009 UICC
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Journals
2009 EN
Ristorcelli Elodie · Beraud Evelyne · Mathieu Sylvie
+2 more
We previously reported that exosomal nanoparticles secreted by human pancreatic tumoral cell lines decrease tumoral cell proliferation through the mitochondria‐dependent apoptotic pathway, because of activation of pro‐apoptotic phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and of glucose synthase kinase‐3β (GSK‐3β). Interactions between exosomal nanoparticles and cells are thought to involve membrane lipid rafts. However, the underlying mechanism is unknown. Here, we report that the interaction of exosomal nanoparticles with pancreatic cancer cells led to decreased expression of hairy and enhancer‐of‐split homolog‐1 (Hes‐1), the intranuclear target of Notch‐1 signaling pathway, and to activation of the apoptotic pathway after a cell cycle arrest in G 0 G 1 phase. Strikingly, the expression level of Notch‐1 pathway components was critical, because exosomal nanoparticles decreased the proliferation of cells in which these partners are either weakly represented, in differentiated adenocarcinoma cells, or inhibited, in poorly differentiated carcinoma cells, by blocking presenilin in the γ‐secretase complex that regulates the Notch‐1 pathway. Overexpression of Notch‐1 intracellular domain resulted in the reversion of the cell proliferation inhibition promoted by exosomal nanoparticles. Blocking presenilin unexpectedly resulted in activation of PTEN and GSK‐3β. Conversely, inhibiting either PTEN or GSK‐3β increased Hes‐1 expression and partially counteracted the inhibition of proliferation promoted by exosomal nanoparticles, highlighting reciprocal regulations between Notch signaling and PTEN/GSK‐3β. We concluded that interactions of exosomal nanoparticles with target cells, at lipid rafts where Notch‐1 pathway partners are localized, hampered the functioning of the Notch‐1 survival pathway and activated the apoptotic pathway, which determines tumoral cell fate. © 2009 UICC
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Journals
2009 EN
Salas Sébastien · Jézéquel Pascal · Campion Loic
+11 more
The therapy regimen of high‐grade osteosarcoma includes chemotherapy followed by surgical resection and postoperative chemotherapy. The degree of necrosis following definitive surgery remains the only reliable prognostic factor and is used to guide the choice of postoperative chemotherapy. The aim of this study was to find molecular markers able to classify patients with an osteosarcoma as good or poor responders to chemotherapy before beginning treatment. Gene expression screening of 20 nonmetastatic high‐grade osteosarcoma patients was performed using cDNA microarray. Expression of selected relevant genes was validated using QRT‐PCR. Immunohistochemistry on tissue microarrays sections of 73 biopsies was performed to investigate protein expression. Fluorescent in situ hybridization was performed for RPL8 gene. We have found that HSD17B10 gene expression was up‐regulated in poor responders and that immunohistochemistry expression of HSD17B10 on biopsy before treatment was correlatedto response to chemotherapy. Other results include correlationof IFITM2 , IFITM3 , and RPL8 gene expression to chemotherapy response. A statistical correlation was found between polysomy 8 or gain of RPL8 and good response to chemotherapy. These data suggest that HSD17B10, RPL8 , IFITM2 , and IFITM3 genes are involved in the response to the chemotherapy and that HSD17B10 may be a therapeutic target. RPL8 and IFITM2 may be useful in the assessment at diagnosis and for stratifying patients taking part in randomized trials. © 2009 UICC
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Journals
2009 EN
Nicholson Linda J. · Smith Paul R. · Hiller Louise
+7 more
Evidence indicates that acquired resistance of cancers to chemotherapeutic agents can occur via epigenetic mechanisms. Down‐regulation of expression of argininosuccinate synthetase (ASS1), the rate‐limiting enzyme in the biosynthesis of arginine, has been associated with the development of platinum resistance in ovarian cancer treated with platinum‐based chemotherapy. The aim of the present study was to analyse epigenetic regulation of ASS1 in ovarian cancer tissue taken at diagnosis and relapse and determine its significance as a predictor of clinical outcome in patients treated with platinum‐based chemotherapy. In addition, expression and epigenetic regulation of ASS1 were analysed in human ovarian cancer cell lines, and ASS1 expression correlated with the ability of the lines to grow in media containing cisplatin, carboplatin or taxol or in arginine‐depleted media. Our results show that aberrant methylation in the ASS1 promoter correlated with transcriptional silencing in ovarian cancer cell lines. ASS1 silencing conferred selective resistance to platinum‐based drugs and conferred arginine auxotrophy and sensitivity to arginine deprivation. In ovarian cancer, ASS1 methylation at diagnosis was associated with significantly reduced overall survival ( p = 0.01) and relapse‐free survival ( p = 0.01). In patients who relapse, ASS1 methylation was significantly more frequent at relapse ( p = 0.008). These data establish epigenetic inactivation of ASS1 as a determinant of response to platinum chemotherapy and imply that transcriptional silencing of ASS1 contributes to treatment failure and clinical relapse in ovarian cancer. The collateral sensitivity of cells lacking endogenous ASS1 to arginine depletion suggests novel therapeutic strategies for the management of relapsed ovarian cancer. © 2009 UICC
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Journals
2009 EN
Scherer Dominique · Nagore Eduardo · Bermejo Justo Lorenzo
+7 more
Variation within the melanocortin receptor 1 ( MC1R ) gene, that influences phenotypic traits and susceptibility to melanoma, is abundant across the populations. We assessed and compared the risk of melanoma in 2 European populations, German and Spanish, by genotyping MC1R variants through direct DNA sequencing from 1,185 melanoma cases and 1,582 controls. The presence of any variant in both populations was associated with a significantly increased risk of melanoma (odds ratio OR = 1.67, 95% confidence interval CI 1.40–1.99). The population attributable fractions (PAF) associated with the MC1R variants in both populations was over 25%. However, the results showed a statistically significant ( p < 0.0001) higher frequency of MC1R variants in the German (70%) than in the Spanish population (60%). The red‐hair colour (RHC) variants, though associated with increased risk in both populations, were more common in the German than in the Spanish population ( p < 0.0001). Interestingly, non‐RHC variants increased the disease risk in the Spanish (OR = 1.60, 95% CI 1.20–2.14) but not in the German population (OR = 1.07, 95% CI 0.80–1.44). Although RHC variants explained a major proportion of the observed PAF in the German population, in the Spanish population the major contributor to the PAF was the non‐RHC V60L variant. We also observed reduced historic linkage disequilibrium between the variants V92M and T314T in the gene in German melanoma cases. In conclusion, our data underscored the unambiguous importance of the MC1R variants towards the population burden of melanoma. However, the variants that are associated with the disease differ between the investigated populations. © 2009 UICC
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Journals
2009 EN
Deville JeanLaurent · Bartoli Catherine · Berenguer Caroline
+12 more
Antiangiogenic therapies are used for advanced clear‐cell renal carcinomas (cRCC), but without curative possibilities, underlining the need for new therapeutic targets. Adrenomedullin (AM), a multifunctional peptide, is highly expressed in several tumors and plays an important role in angiogenesis and tumor growth through its receptors: calcitonin receptor‐like receptor/receptor activity‐modifying protein 2 and 3 (CLR/RAMP2 and CLR/RAMP3). In this study, real‐time quantitative reverse‐transcription‐PCR showed AM mRNA levels were higher in cRCC and in chromophobe renal carcinomas (chRCC) than in normal renal tissue. Interestingly, AM mRNA expression in cRCC correlated strongly with VEGF‐A mRNA expression. Immunohistochemically, AM, CLR and RAMP2 were localized in the carcinomatous epithelial compartment of cRCC. Interestingly, RAMP3 immunostaining was found only in the inflammatory cells that infiltrated tumors, suggesting a cross talk between tumor cells and the microenvironment. We also observed that cRCC cells BIZ and 786‐O expressed and secreted AM into the culture medium. In vitro, exogenous AM treatment stimulated cell proliferation, migration and invasion, indicating the cell can respond to AM. The action of AM was specific and was mediated by the CLR/RAMP2 and CLR/RAMP3 receptors. Clinical data showed the prognostic value of AM. High AM mRNA levels were associated with an increased risk of relapse after curative nephrectomy for cRCC. These findings highlight the implication of the AM pathway in the metastatic process and the prognostic relevance of AM in cRCC and point to a potential new therapeutic target. © 2009 UICC
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