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Pascaline Gaildrat,
Sophie Krieger,
Daniela Di Giacomo,
Julie Abdat, Françoise Révillion,
Sandrine Caputo,
Dominique Vaur,
Estelle Jamard,
Elodie Bohers,
Danielle Ledemeney,
Jean-Philippe Peyrat,
Claude Houdayer,
Etienne Rouleau,
Rosette Lidereau,
Thierry Frébourg,
Agnès Hardouin,
Mario Tosi,
Alexandra Martins
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ABSTRACT: Exonic variants of unknown biological significance (VUS) identified in patients can affect mRNA splicing, either by changing 5' or 3' splice sites or by modifying splicing regulatory elements. Bioinformatic predictions of these elements are still inaccurate and only few such elements have been functionally mapped in BRCA2. We studied the effect on splicing of eight exon 7 VUS, selected from the French UMD-BRCA2 mutation database.
We performed splicing minigene assays and analyses of patient RNA. We also developed a pyrosequencing-based quantitative assay, to measure, in patient RNA, the relative contribution of each allele to the production of exon 7-containing transcripts. Moreover, an exonic splicing enhancer (ESE)-dependent minigene assay was used to evaluate the splicing regulatory properties of wild-type and mutant segments.
Six out of the eight variants induced splicing defects. In the minigene assay, c.517G>T and c.631G>A altered the natural splice sites, c.572A>G created a new 5' splice site, and c.520C>T, c.587G>A and c.617C>G induced exon 7 skipping (66%, 25% and 46%, respectively). Pyrosequencing of patient RNA confirmed these levels of exon skipping for c.520C>T and c.617C>G. Results from the ESE-dependent minigene assay indicated that c.520C>T and c.587G>A disturb splicing regulatory elements.
BRCA2 exon 7 splicing is regulated by multiple exonic elements and is sensitive to disease-associated sequence variations. Measurements of allelic imbalance in patient-derived RNA and/or quantitative analyses using minigene assays provide valuable estimates of the extent of partial splicing defects. Assessment of pathogenicity of variants with partial splicing effect awaits additional evidence and especially the completion of segregation analyses.
Journal of Medical Genetics 09/2012; 49(10):609-17. · 6.36 Impact Factor
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ABSTRACT: The effects of progesterone are mediated by 2 progesterone receptors (PR), PR-A and PR-B. Recently, several lines of evidence have suggested that reduced PR expression may result from hyperactivity in the signaling cascade generated by the HER/ErbB family. The aim of this study was to analyze the relationships between PR isoforms and the network of the HER/ErbB receptors and ligands in breast cancer.
299 breast cancer samples from patients operated in our institute for locoregional disease between May 1989 and December 1991 were included. The mRNA expression of total PR-A+B isoforms and PR-B isoform were quantified by real time quantitative RT-PCR using TaqMan® probes.
mRNA levels of the PR isoforms positively correlated with protein levels of estradiol receptors (ER) and PR. The PR isoforms mRNA levels were inversely correlated with clinicopathological markers of tumor aggressiveness, such as SBR grading and lymph node involvement. The PR isoforms positively correlated with the mRNA levels of HER/ErbB receptors and ligands associated with a more differentiated phenotype (HER3, HER4, EGF, AREG, NRG3 and NRG4) while they correlated negatively with those associated with aggressiveness (EGFR, TGFa, HB-EGF, EREG, and NRG2).
Our results demonstrate the existence of strong correlations between mRNA levels of the PR isoforms, protein levels of hormone receptors, HER/ErbB receptors and ligands network, and thus suggest that crosstalks between PR and the HER family are a hallmark of breast cancer growth.
The International journal of biological markers 04/2012; 27(2):e111-7. · 1.48 Impact Factor
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Jean Christophe Théry,
Sophie Krieger,
Pascaline Gaildrat, Françoise Révillion,
Marie-Pierre Buisine,
Audrey Killian,
Christiane Duponchel,
Antoine Rousselin,
Dominique Vaur,
Jean-Philippe Peyrat,
Pascaline Berthet,
Thierry Frébourg,
Alexandra Martins,
Agnès Hardouin,
Mario Tosi
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ABSTRACT: A large fraction of sequence variants of unknown significance (VUS) of the breast and ovarian cancer susceptibility genes BRCA1 and BRCA2 may induce splicing defects. We analyzed 53 VUSs of BRCA1 or BRCA2, detected in consecutive molecular screenings, by using five splicing prediction programs, and we classified them into two groups according to the strength of the predictions. In parallel, we tested them by using functional splicing assays. A total of 10 VUSs were predicted by two or more programs to induce a significant reduction of splice site strength or activation of cryptic splice sites or generation of new splice sites. Minigene-based splicing assays confirmed four of these predictions. Five additional VUSs, all at internal exon positions, were not predicted to induce alterations of splice sites, but revealed variable levels of exon skipping, most likely induced by the modification of exonic splicing regulatory elements. We provide new data in favor of the pathogenic nature of the variants BRCA1 c.212+3A>G and BRCA1 c.5194-12G>A, which induced aberrant out-of-frame mRNA forms. Moreover, the novel variant BRCA2 c.7977-7C>G induced in frame inclusion of 6 nt from the 3' end of intron 17. The novel variants BRCA2 c.520C>T and BRCA2 c.7992T>A induced incomplete skipping of exons 7 and 18, respectively. This work highlights the contribution of splicing minigene assays to the assessment of pathogenicity, not only when patient RNA is not available, but also as a tool to improve the accuracy of bioinformatics predictions.
European journal of human genetics: EJHG 06/2011; 19(10):1052-8. · 3.56 Impact Factor
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Mohamed Hebbar,
Antoine Adenis, Françoise Révillion,
Alain Duhamel,
Olivier Romano,
Stéphanie Truant,
Christian Libersa,
Claire Giraud,
Jean-Pierre Triboulet,
François-René Pruvot,
Jean-Philippe Peyrat
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ABSTRACT: Some host-related factors may predict the risk of metastasis after surgery of colorectal cancer (CRC). The endothelial adhesion molecule E-selectin is implicated in the metastatic spread of CRC. We postulated that some polymorphisms within the E-selectin gene, especially the S128R polymorphism, may increase the risk of metastases by facilitating adhesion of tumour cells to the endothelium. We collected blood samples for DNA extraction from 264 patients treated for stage II or III CRC and from 310 healthy controls in order to assess three polymorphisms within the E-selectin gene (S128R, G98T and L554F) and one within the P-selectin gene (V640L). Genotypes were analysed by the allelic discrimination TaqMan real-time PCR assay. The S128R polymorphism was detected in 59 patients (22.3%) and was strictly correlated with the G98T polymorphism. In multivariate analysis, the S128R polymorphism was associated with shorter event-free survival (EFS) and overall survival (OS) in the whole population (EFS: P=.003, HR 1.82, 95% CI 1.23-2.70; OS: P<10(-4), HR 4.31, 95% CI 2.46-10.99), in patients with stage II CRC(EFS: P=.04, HR 1.92, 95% CI 1.02-3.60; OS: P=.02, HR 4.44, 95% CI 1.16-17.03), and in patients with stage III CRC (EFS: P=.04, HR 1.68, 95% CI 1.01-2.80; OS: P=.001, HR 4.04, 95% CI 1.73-9.46). L554F and V640L polymorphisms had no prognostic value. The S128R polymorphism is a constitutional factor associated with a higher risk of relapse and death in patients treated for CRC. This polymorphism detection may permit better selection of patients suitable for adjuvant therapy, especially among those with stage II disease.
European journal of cancer (Oxford, England: 1990) 04/2009; 45(10):1871-6. · 4.12 Impact Factor
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ABSTRACT: Although it is well established that some protein tyrosine kinases have a prognostic value in breast cancer, the involvement of protein tyrosine phosphatases (PTPs) is poorly substantiated for breast tumors. Three of these enzymes (PTP-gamma, LAR, and PTPL1) are already known to be regulated by estrogens or their antagonists in human breast cancer cells. We used a real-time reverse transcriptase polymerase chain reaction method to test the expression levels of PTP-gamma, LAR and its neuronal isoform, and PTPL1 in a training set of RNA from 59 breast tumors. We sought correlations between levels of these molecular markers, current tumor markers, and survival. We then quantified the expression level of the selected phosphatase in 232 additional samples, resulting in a testing set of 291 breast tumor RNAs from patients with a median follow-up of 6.4 years. The Spearman nonparametric test revealed correlations between PTPL1 expression and differentiation markers. Cox univariate analysis of the overall survival studies demonstrated that PTPL1 is a prognostic factor [risk ratio (RR)=0.45], together with the progesterone receptor (PR) (RR=0.52) and node involvement (RR=1.58). In multivariate analyses, PTPL1 and PR retained their prognostic value (RRs of 0.48 and 0.55, respectively). This study demonstrates for the first time that PTPL1 expression level is an independent prognostic indicator of favorable outcome for patients with breast cancer. In conjunction with our mechanistic studies, this finding identifies PTPL1 as an important regulatory element of human breast tumor aggressiveness and sensitivity to treatments such as antiestrogens and antiaromatase.
International Journal of Cancer 10/2008; 124(3):638-43. · 5.44 Impact Factor
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ABSTRACT: The sex steroid progesterone is essential for the proliferation and differentiation of the mammary gland epithelium during pregnancy. In relation to this, in vitro studies using breast carcinoma T47D cells have demonstrated a biphasic progesterone response, consisting of an initial proliferative burst followed by a sustained growth arrest. However, the transcriptional factors acting with the progesterone receptor (PR) to mediate the progesterone effects on mammary cell growth and differentiation remain to be determined. Recently, it has been demonstrated that the transcriptional regulating protein of 132 kDa (TReP-132), initially identified as a regulator of steroidogenesis, is also a cell growth suppressor. Similar to progesterone-bound PR, TReP-132 acts by inducing the gene expression of the G1 cyclin-dependent kinase inhibitors p21WAF1/Cip1 (p21) and p27Kip1 (p27). The putative interaction between TReP-132 and progesterone pathways in mammary cells was therefore analyzed in the present study. Our results show that TReP-132 interacts in vitro and in T47D cells with progesterone-activated PR. TReP-132 synergizes with progesterone-bound PR to trans activate the p21 and p27 gene promoters at proximal Sp1-binding sites. Moreover, TReP-132 overexpression and knockdown, respectively, increased or prevented the induction of p21 and p27 gene expression by progesterone. As a consequence, TReP-132 knockdown also resulted in the loss of the inhibitory effects of progesterone on pRB phosphorylation, G1/S cell cycle progression, and cell proliferation. Furthermore, the knockdown of TReP-132 expression also prevented the induction of both early and terminal markers of breast cell differentiation which had been previously identified as progesterone target genes. As well, the progesterone-induced accumulation of lipid vacuoles was inhibited in the TReP-132-depleted cells. Finally, TReP-132 gene expression levels increased following progesterone treatment, indicating the existence of a positive auto-regulatory loop between PR and TReP-132. Taken together, these data identify TReP-132 as a coactivator of PR mediating the growth-inhibitory and differentiation effects of progesterone on breast cancer cells.
Molecular and Cellular Biology 11/2006; 26(20):7632-44. · 5.53 Impact Factor
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ABSTRACT: Leptin and obesity are clearly related, and obesity is associated with an increased risk of breast cancer. We therefore measured the expression of leptin and its two main receptor isoforms, OBR-L and OBR-S, in 322 breast cancers. We analyzed their relations with the classical prognostic factors and with survival to establish their links with breast cancer.
The expression of leptin and its receptors was quantified by real-time reverse transcription-PCR, using TaqMan fluorogenic probes and an ABI PRISM 7700 sequence detector system (Applied Biosystems, Courtaboeuf, France). TATA box binding protein was used to normalize expression. The human breast cancer cell, SK-BR-3, expressing the three targets, was chosen as the calibrator sample (i.e., target expression = 1).
All the tumors expressed both receptors, and 318 of 322 expressed leptin. These three variables correlated positively with each other and with estradiol and progesterone receptors, whereas they correlated negatively with histoprognostic grading and tumor diameter. OBR-L/OBR-S expression was inversely correlated with progesterone receptors. Patients with elevated OBR-S expression had longer relapse-free survival (P = 0.008), whereas high OBR-L/OBR-S was associated with a shorter relapse-free survival (P = 0.05). In Cox multivariate analyses, OBR-S maintained its prognostic value (P = 0.02; relative risk, 0.51).
This study shows that (a) almost all of the breast cancers coexpress leptin and its two main isoforms of receptors, suggesting that the human epithelial breast cancer cells respond to leptin acting via an autocrine pathway; (b) high expression levels of leptin and leptin receptors are biological markers of a more differentiated phenotype; and that (c) OBR-S is an independent prognostic factor.
Clinical Cancer Research 05/2006; 12(7 Pt 1):2088-94. · 7.74 Impact Factor
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ABSTRACT: The effects of progesterone derivatives on breast cancer development are still controversial, probably accounting for their biphasic, opposed effects on mammary cell-cycle regulation. Here, we demonstrate in vitro that the growth-inhibitory effects of progesterone on breast cancer T-47D cells require the transcriptional upregulation of the cyclin-dependent kinase inhibitor p27(Kip1) (p27) gene. A statistical analysis of human tumor biopsies further indicates that p27 mRNA levels correlate to progesterone receptor (PR) levels. Moreover, p27 gene expression is inversely associated with tumor aggressiveness, and is a prognostic factor of favorable disease outcome. Thus, progesterone derivatives selectively activating the p27 gene promoter could be promising drugs against breast cancer progression.
FEBS Letters 11/2005; 579(25):5535-41. · 3.54 Impact Factor
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ABSTRACT: The transcriptional regulating protein of 132 kDa (TReP-132) has been identified in steroidogenic tissues, where it acts as a coactivator of steroidogenic factor 1 (SF-1). We show here that TReP-132 plays a role in the control of cell proliferation. In human HeLa cells, TReP-132 knockdown by using small interfering RNA resulted in increased G(1)-->S cell cycle progression. The growth-inhibitory effects of TReP-132 was further shown to be mediated by induction of G(1) cyclin-dependent kinase inhibitors p21(WAF1) (p21) and p27(KIP1) (p27) expression levels. As a consequence, G(1) cyclin/cyclin-dependent kinase activities and pRB phosphorylation were markedly reduced, and cell cycle progression was blocked in the G(1) phase. The stimulatory effect of TReP-132 on p21 and p27 gene transcription involved interaction of TReP-132 with the transcription factor Sp1 at proximal Sp1-binding sites in their promoters. Moreover, in different breast tumor cell lines, endogenous TReP-132 expression was positively related with a lower proliferation rate. In addition, TReP-132 knockdown resulted in enhanced cell proliferation and lowered p21 and p27 mRNA levels in the steroid-responsive and nonresponsive T-47D and MDA-MB-231 cell lines, respectively. Finally, a statistic profiling of human breast tumor samples highlighted that expression of TReP-132 is correlated with p21 and p27 levels and is associated with lower tumor incidence and aggressiveness. Together, these results identify TReP-132 as a basal cell cycle regulatory protein acting, at least in part, by interacting with Sp1 to activate the p21 and p27 gene promoters.
Molecular and Cellular Biology 06/2005; 25(11):4335-48. · 5.53 Impact Factor
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ABSTRACT: We measured the expression of ERM gene, a nuclear transcription factor belonging to the ets family, in a series of 364 unselected primary breast cancers from patients who underwent locoregional surgery in the Centre Oscar Lambret between May 1989 and December 1991. The expression of ERM was quantified with a real-time one-step reverse transcription-PCR assay based on the 5'-nuclease activity of the TaqDNA polymerase and with an Abi Prism 7700 Sequence Detector System (Applied Biosystems, Courtaboeuf, France). ERM was positively correlated (Spearman test) to epidermal growth factor receptor (EGFR; P < 0.001, r = 0.296) and to histoprognostic grading (P = 0.044, r = 0.112), whereas it was negatively correlated to estradiol receptors (P = 0.019, r = -0.124), HER3 (c-erbB-3; P = 0.01, r = -0.135), and HER4 (c-erbB-4; P = 0.003, r = -0.154). Using the chi2 test, a positive relationship was found between the expression of ERM and EGFR (chi2 = 7.795, P = 0.007). In overall survival studies, Cox univariate analyses demonstrated a prognostic value of ERM (P = 0.006; risk ratio, 2.95) besides the classical prognostic factors histoprognostic grading, node involvement, tumor size, estradiol receptors, progesterone receptors, EGFR, HER3, and HER4. In multivariate analyses, ERM preserved its prognostic value (P = 0.004; risk ratio, 3.779) together with histoprognostic grading, tumor size, estradiol receptors, and progesterone receptors. In relapse-free survival studies, univariate analyses demonstrated that histoprognostic grading, node involvement, tumor size, and HER4 were prognostic factors. These parameters, except histoprognostic grading, retained their prognostic value in multivariate analyses. This study demonstrates for the first time that ERM gene expression is an independent adverse prognostic factor for overall survival in breast cancer patients.
Clinical Cancer Research 11/2004; 10(21):7297-303. · 7.74 Impact Factor
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Clinical Chemistry 02/2004; 50(1):203-6. · 7.91 Impact Factor
