Biologie du cancer du sein

Publications

Année de publication : 2016

Christophe Couderc, Alizée Boin, Laetitia Fuhrmann, Anne Vincent-Salomon, Vinay Mandati, Yann Kieffer, Fatima Mechta-Grigoriou, Laurence Del Maestro, Philippe Chavrier, David Vallerand, Isabelle Brito, Thierry Dubois, Leanne De Koning, Daniel Bouvard, Daniel Louvard, Alexis Gautreau, Dominique Lallemand (2016 Jan 26)

AMOTL1 integrates Hippo signaling to promote breast cancer progression by inducing tumor cell proliferation and migration

Neoplasia (New York, N.Y.) : 10-24 : DOI : 10.1016/j.neo.2015.11.010 En savoir plus
Résumé

The Hippo signaling network is a key regulator of cell fate. In the recent years, it was shown that its implication in cancer goes well beyond the sole role of YAP transcriptional activity and its regulation by the canonical MST/LATS kinase cascade. Here we show that the motin family member AMOTL1 is an important effector of Hippo signaling in breast cancer. AMOTL1 connects Hippo signaling to tumor cell aggressiveness. We show that both canonical and noncanonical Hippo signaling modulates AMOTL1 levels. The tumor suppressor Merlin triggers AMOTL1 proteasomal degradation mediated by the NEDD family of ubiquitin ligases through direct interaction. In parallel, YAP stimulates AMOTL1 expression. The loss of Merlin expression and the induction of Yap activity that are frequently observed in breast cancers thus result in elevated AMOTL1 levels. AMOTL1 expression is sufficient to trigger tumor cell migration and stimulates proliferation by activating c-Src. In a large cohort of human breast tumors, we show that AMOTL1 protein levels are upregulated during cancer progression and that, importantly, the expression of AMOTL1 in lymph node metastasis appears predictive of the risk of relapse. Hence we uncover an important mechanism by which Hippo signaling promotes breast cancer progression by modulating the expression of AMOTL1.

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Magali Michaut, Suet-Feung Chin, Ian Majewski, Tesa M Severson, Tycho Bismeijer, Leanne de Koning, Justine K Peeters, Philip C Schouten, Oscar M Rueda, Astrid J Bosma, Finbarr Tarrant, Yue Fan, Beilei He, Zheng Xue, Lorenza Mittempergher, Roelof J C Kluin, Jeroen Heijmans, Mireille Snel, Bernard Pereira, Andreas Schlicker, Elena Provenzano, Hamid Raza Ali, Alexander Gaber, Gillian O'Hurley, Sophie Lehn, Jettie J F Muris, Jelle Wesseling, Elaine Kay, Stephen John Sammut, Helen A Bardwell, Aurélie S Barbet, Floriane Bard, Caroline Lecerf, Darran P O'Connor, Daniël J Vis, Cyril H Benes, Ultan McDermott, Mathew J Garnett, Iris M Simon, Karin Jirström, Thierry Dubois, Sabine C Linn, William M Gallagher, Lodewyk F A Wessels, Carlos Caldas, Rene Bernards (2016 Jan 6)

Integration of genomic, transcriptomic and proteomic data identifies two biologically distinct subtypes of invasive lobular breast cancer.

Scientific reports : 18517 : DOI : 10.1038/srep18517 En savoir plus
Résumé

Invasive lobular carcinoma (ILC) is the second most frequently occurring histological breast cancer subtype after invasive ductal carcinoma (IDC), accounting for around 10% of all breast cancers. The molecular processes that drive the development of ILC are still largely unknown. We have performed a comprehensive genomic, transcriptomic and proteomic analysis of a large ILC patient cohort and present here an integrated molecular portrait of ILC. Mutations in CDH1 and in the PI3K pathway are the most frequent molecular alterations in ILC. We identified two main subtypes of ILCs: (i) an immune related subtype with mRNA up-regulation of PD-L1, PD-1 and CTLA-4 and greater sensitivity to DNA-damaging agents in representative cell line models; (ii) a hormone related subtype, associated with Epithelial to Mesenchymal Transition (EMT), and gain of chromosomes 1q and 8q and loss of chromosome 11q. Using the somatic mutation rate and eIF4B protein level, we identified three groups with different clinical outcomes, including a group with extremely good prognosis. We provide a comprehensive overview of the molecular alterations driving ILC and have explored links with therapy response. This molecular characterization may help to tailor treatment of ILC through the application of specific targeted, chemo- and/or immune-therapies.

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Année de publication : 2015

Elodie Manié, Tatiana Popova, Aude Battistella, Julien Tarabeux, Virginie Caux-Moncoutier, Lisa Golmard, Nicholas K Smith, Christopher R Mueller, Odette Mariani, Brigitte Sigal-Zafrani, Thierry Dubois, Anne Vincent-Salomon, Claude Houdayer, Dominique Stoppa-Lyonnet, Marc-Henri Stern (2015 Aug 29)

Genomic hallmarks of homologous recombination deficiency in invasive breast carcinomas.

International journal of cancer : 891-900 : DOI : 10.1002/ijc.29829 En savoir plus
Résumé

Therapeutic strategies targeting Homologous Recombination Deficiency (HRD) in breast cancer requires patient stratification. The LST (Large-scale State Transitions) genomic signature previously validated for triple-negative breast carcinomas (TNBC) was evaluated as biomarker of HRD in luminal (hormone receptor positive) and HER2-overexpressing (HER2+) tumors. The LST genomic signature related to the number of large-scale chromosomal breakpoints in SNP-array tumor profile was applied to identify HRD in in-house and TCGA sets of breast tumors, in which the status of BRCA1/2 and other genes was also investigated. In the in-house dataset, HRD was predicted in 5% (20/385) of sporadic tumors luminal or HER2+ by the LST genomic signature and the inactivation of BRCA1, BRCA2 or RAD51C confirmed this prediction in 75% (12/16) of the tested cases. In 14% (6/43) of tumors occurring in BRCA1/2 mutant carriers, the corresponding wild-type allele was retained emphasizing the importance of determining the tumor status. In the TCGA luminal and HER2+ subtypes HRD incidence was estimated at 5% (18/329, 95%CI: 5-8%) and 2% (1/59, 95%CI: 2-9%), respectively. In TNBC cisplatin-based neo-adjuvant clinical trials, HRD is shown to be a necessary condition for cisplatin sensitivity. This analysis demonstrates the high performance of the LST genomic signature for HRD detection in breast cancers, which suggests its potential as a biomarker for genetic testing and patient stratification for clinical trials evaluating platinum salts and PARP inhibitors.

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Loredana Martignetti, Bruno Tesson, Anna Almeida, Andrei Zinovyev, Gordon C Tucker, Thierry Dubois, Emmanuel Barillot (2015 Jun 1)

Detection of miRNA regulatory effect on triple negative breast cancer transcriptome.

BMC genomics : S4 : DOI : 10.1186/1471-2164-16-S6-S4 En savoir plus
Résumé

Identifying key microRNAs (miRNAs) contributing to the genesis and development of a particular disease is a focus of many recent studies. We introduce here a rank-based algorithm to detect miRNA regulatory activity in cancer-derived tissue samples which combines measurements of gene and miRNA expression levels and sequence-based target predictions. The method is designed to detect modest but coordinated changes in the expression of sequence-based predicted target genes. We applied our algorithm to a cohort of 129 tumour and healthy breast tissues and showed its effectiveness in identifying functional miRNAs possibly involved in the disease. These observations have been validated using an independent publicly available breast cancer dataset from The Cancer Genome Atlas. We focused on the triple negative breast cancer subtype to highlight potentially relevant miRNAs in this tumour subtype. For those miRNAs identified as potential regulators, we characterize the function of affected target genes by enrichment analysis. In the two independent datasets, the affected targets are not necessarily the same, but display similar enriched categories, including breast cancer related processes like cell substrate adherens junction, regulation of cell migration, nuclear pore complex and integrin pathway. The R script implementing our method together with the datasets used in the study can be downloaded here (http://bioinfo-out.curie.fr/projects/targetrunningsum).

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Céline Baldeyron, Amélie Brisson, Bruno Tesson, Fariba Némati, Stéphane Koundrioukoff, Elie Saliba, Leanne De Koning, Elise Martel, Mengliang Ye, Guillem Rigaill, Didier Meseure, André Nicolas, David Gentien, Didier Decaudin, Michelle Debatisse, Stéphane Depil, Francisco Cruzalegui, Alain Pierré, Sergio Roman-Roman, Gordon C Tucker, Thierry Dubois (2015 May 26)

TIPIN depletion leads to apoptosis in breast cancer cells.

Molecular oncology : 1580-98 : DOI : 10.1016/j.molonc.2015.04.010 En savoir plus
Résumé

Triple-negative breast cancer (TNBC) is the breast cancer subgroup with the most aggressive clinical behavior. Alternatives to conventional chemotherapy are required to improve the survival of TNBC patients. Gene-expression analyses for different breast cancer subtypes revealed significant overexpression of the Timeless-interacting protein (TIPIN), which is involved in the stability of DNA replication forks, in the highly proliferative associated TNBC samples. Immunohistochemistry analysis showed higher expression of TIPIN in the most proliferative and aggressive breast cancer subtypes including TNBC, and no TIPIN expression in healthy breast tissues. The depletion of TIPIN by RNA interference impairs the proliferation of both human breast cancer and non-tumorigenic cell lines. However, this effect may be specifically associated with apoptosis in breast cancer cells. TIPIN silencing results in higher levels of single-stranded DNA (ssDNA), indicative of replicative stress (RS), in TNBC compared to non-tumorigenic cells. Upon TIPIN depletion, the speed of DNA replication fork was significantly decreased in all BC cells. However, TIPIN-depleted TNBC cells are unable to fire additional replication origins in response to RS and therefore undergo apoptosis. TIPIN knockdown in TNBC cells decreases tumorigenicity in vitro and delays tumor growth in vivo. Our findings suggest that TIPIN is important for the maintenance of DNA replication and represents a potential treatment target for the worst prognosis associated breast cancers, such as TNBC.

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Sylvie Maubant, Bruno Tesson, Virginie Maire, Mengliang Ye, Guillem Rigaill, David Gentien, Francisco Cruzalegui, Gordon C Tucker, Sergio Roman-Roman, Thierry Dubois (2015 Apr 8)

Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells.

PloS one : e0122333 : DOI : 10.1371/journal.pone.0122333 En savoir plus
Résumé

The canonical Wnt/β-catenin pathway is activated in triple-negative breast cancer (TNBC). The activation of this pathway leads to the expression of specific target genes depending on the cell/tissue context. Here, we analyzed the transcriptome of two different TNBC cell lines to define a comprehensive list of Wnt target genes. The treatment of cells with Wnt3a for 6h up-regulated the expression (fold change > 1.3) of 59 genes in MDA-MB-468 cells and 241 genes in HCC38 cells. Thirty genes were common to both cell lines. Beta-catenin may also be a transcriptional repressor and we found that 18 and 166 genes were down-regulated in response to Wnt3a treatment for 6h in MDA-MB-468 and HCC38 cells, respectively, of which six were common to both cell lines. Only half of the activated and the repressed transcripts have been previously described as Wnt target genes. Therefore, our study reveals 137 novel genes that may be positively regulated by Wnt3a and 104 novel genes that may be negatively regulated by Wnt3a. These genes are involved in the Wnt pathway itself, and also in TGFβ, p53 and Hedgehog pathways. Thorough characterization of these novel potential Wnt target genes may reveal new regulators of the canonical Wnt pathway. The comparison of our list of Wnt target genes with those published in other cellular contexts confirms the notion that Wnt target genes are tissue-, cell line- and treatment-specific. Genes up-regulated in Wnt3a-stimulated cell lines were more strongly expressed in TNBC than in luminal A breast cancer samples. These genes were also overexpressed, but to a much lesser extent, in HER2+ and luminal B tumors. We identified 72 Wnt target genes higher expressed in TNBCs (17 with a fold change >1.3) which may reflect the chronic activation of the canonical Wnt pathway that occurs in TNBC tumors.

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Année de publication : 2014

Sylvain Lefort, Carine Joffre, Yann Kieffer, Anne-Marie Givel, Brigitte Bourachot, Giulia Zago, Ivan Bieche, Thierry Dubois, Didier Meseure, Anne Vincent-Salomon, Jacques Camonis, Fatima Mechta-Grigoriou (2014 Nov 27)

Inhibition of autophagy as a new means of improving chemotherapy efficiency in high-LC3B triple-negative breast cancers.

Autophagy : 2122-42 : DOI : 10.4161/15548627.2014.981788 En savoir plus
Résumé

The triple-negative breast cancer (TN BC) subtype is the most aggressive form of invasive BC. Despite intensive efforts to improve BC treatments, patients with TN BC continue to exhibit poor survival, with half developing resistance to chemotherapy. Here we identify autophagy as a key mechanism in the progression and chemoresistance of a subset of TN tumors. We demonstrate that LC3B, a protein involved in autophagosome formation, is a reliable marker of poor prognosis in TN BC, validating this prognostic value at both the mRNA and protein levels in several independent cohorts. We also show that LC3B has no prognostic value for other BC subtypes (Luminal or HER2 BC), thus revealing a specific impact of autophagy on TN tumors. Autophagy is essential for the proliferative and invasive properties in 3D of TN BC cells characterized by high LC3B levels. Interestingly, the activity of the transcriptional co-activator YAP1 (Yes-associated protein 1) is regulated by the autophagy process and we identify YAP1 as a new actor in the autophagy-dependent proliferative and invasive properties of high-LC3B TN BC. Finally, inhibiting autophagy by silencing ATG5 or ATG7 significantly impaired high-LC3B TN tumor growth in vivo. Moreover, using a patient-derived TN tumor transplanted into mice, we show that an autophagy inhibitor, chloroquine, potentiates the effects of chemotherapeutic agents. Overall, our data identify LC3B as a new prognostic marker for TN BC and the inhibition of autophagy as a promising therapeutic strategy for TN BC patients.

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Alizée Boin, Anne Couvelard, Christophe Couderc, Isabel Brito, Dan Filipescu, Michel Kalamarides, Pierre Bedossa, Leanne De Koning, Carine Danelsky, Thierry Dubois, Philippe Hupé, Daniel Louvard, Dominique Lallemand (2014 Feb 22)

Proteomic screening identifies a YAP-driven signaling network linked to tumor cell proliferation in human schwannomas.

Neuro-oncology : 1196-209 : DOI : 10.1093/neuonc/nou020 En savoir plus
Résumé

Inactivation of the NF2 gene predisposes to neurofibromatosis type II and the development of schwannomas. In vitro studies have shown that loss of NF2 leads to the induction of mitogenic signaling mediated by receptor tyrosine kinases (RTKs), MAP kinase, AKT, or Hippo pathways. The goal of our study was to evaluate the expression and activity of these signaling pathways in human schwannomas in order to identify new potential therapeutic targets.

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Année de publication : 2013

Sophie Broutin, Frédéric Commo, Leanne De Koning, Bérengère Marty-Prouvost, Ludovic Lacroix, Monique Talbot, Bernard Caillou, Thierry Dubois, Anderson J Ryan, Corinne Dupuy, Martin Schlumberger, Jean-Michel Bidart (2013 Nov 22)

Changes in signaling pathways induced by vandetanib in a human medullary thyroid carcinoma model, as analyzed by reverse phase protein array.

Thyroid : official journal of the American Thyroid Association : 43-51 : DOI : 10.1089/thy.2013.0514 En savoir plus
Résumé

Medullary thyroid carcinoma (MTC) is a rare tumor that is caused by activating mutations in the proto-oncogene RET. Vandetanib, a tyrosine-kinase inhibitor, has been recently approved to treat adult patients with metastatic MTC. The aim of this study was to investigate changes in signaling pathways induced by vandetanib treatment in preclinical MTC models, using the reverse-phase protein array method (RPPA).

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Julien Calderaro, Sandra Rebouissou, Leanne de Koning, Asma Masmoudi, Aurélie Hérault, Thierry Dubois, Pascale Maille, Pascale Soyeux, Mathilde Sibony, Alexandre de la Taille, Dimitri Vordos, Thierry Lebret, François Radvanyi, Yves Allory (2013 Oct 15)

PI3K/AKT pathway activation in bladder carcinogenesis.

International journal of cancer : 1776-84 : DOI : 10.1002/ijc.28518 En savoir plus
Résumé

The PI3K/AKT pathway is considered to play a major role in bladder carcinogenesis, but its relationships with other molecular alterations observed in bladder cancer remain unknown. We investigated PI3K/AKT pathway activation in a series of human bladder urothelial carcinomas (UC) according to PTEN expression, PTEN deletions and FGFR3, PIK3CA, KRAS, HRAS, NRAS and TP53 gene mutations. The series included 6 normal bladder urothelial samples and 129 UC (Ta n = 25, T1 n = 34, T2-T3-T4 n = 70). Expression of phospho-AKT (pAKT), phospho-S6-Ribosomal Protein (pS6) (one downstream effector of PI3K/AKT pathway) and PTEN was evaluated by reverse phase protein Array. Expression of miR-21, miR-19a and miR-222, known to regulate PTEN expression, was also evaluated. pAKT expression levels were higher in tumors than in normal urothelium (p < 0.01), regardless of stage and showed a weak and positive correlation with pS6 (Spearman coefficient RS = 0.26; p = 0.002). No association was observed between pAKT or pS6 expression and the gene mutations studied. PTEN expression was decreased in PTEN-deleted tumors, and in T1 (p = 0.0089) and T2-T3-T4 (p < 0.001) tumors compared to Ta tumors; it was also negatively correlated with miR-19a (RS = -0.50; p = 0.0088) and miR-222 (RS = -0.48; p = 0.0132), but not miR-21 (RS = -0.27; p = 0.18) expression. pAKT and PTEN expressions were not negatively correlated, and, on the opposite, a positive and moderate correlation was observed in Ta (RS = 0.54; p = 0.0056) and T1 (RS = 0.56; p = 0.0006) tumors. Our study suggests that PI3K/AKT pathway activation occurs in the entire spectrum of bladder UC regardless of stage or known most frequent molecular alterations, and independently of low PTEN expression.

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Virginie Maire, Céline Baldeyron, Marion Richardson, Bruno Tesson, Anne Vincent-Salomon, Eléonore Gravier, Bérengère Marty-Prouvost, Leanne De Koning, Guillem Rigaill, Aurélie Dumont, David Gentien, Emmanuel Barillot, Sergio Roman-Roman, Stéphane Depil, Francisco Cruzalegui, Alain Pierré, Gordon C Tucker, Thierry Dubois (2013 May 24)

TTK/hMPS1 is an attractive therapeutic target for triple-negative breast cancer.

PloS one : e63712 : DOI : 10.1371/journal.pone.0063712 En savoir plus
Résumé

Triple-negative breast cancer (TNBC) represents a subgroup of breast cancers (BC) associated with the most aggressive clinical behavior. No targeted therapy is currently available for the treatment of patients with TNBC. In order to discover potential therapeutic targets, we searched for protein kinases that are overexpressed in human TNBC biopsies and whose silencing in TNBC cell lines causes cell death. A cohort including human BC biopsies obtained at Institut Curie as well as normal tissues has been analyzed at a gene-expression level. The data revealed that the human protein kinase monopolar spindle 1 (hMPS1), also known as TTK and involved in mitotic checkpoint, is specifically overexpressed in TNBC, compared to the other BC subgroups and healthy tissues. We confirmed by immunohistochemistry and reverse phase protein array that TNBC expressed higher levels of TTK protein compared to the other BC subgroups. We then determined the biological effects of TTK depletion by RNA interference, through analyses of tumorigenic capacity and cell viability in different human TNBC cell lines. We found that RNAi-mediated depletion of TTK in various TNBC cell lines severely compromised their viability and their ability to form colonies in an anchorage-independent manner. Moreover, we observed that TTK silencing led to an increase in H2AX phosphorylation, activation of caspases 3/7, sub-G1 cell population accumulation and high annexin V staining, as well as to a decrease in G1 phase cell population and an increased aneuploidy. Altogether, these data indicate that TTK depletion in TNBC cells induces apoptosis. These results point out TTK as a protein kinase overexpressed in TNBC that may represent an attractive therapeutic target specifically for this poor prognosis associated subgroup of breast cancer.

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Cécile Laurent, David Gentien, Sophie Piperno-Neumann, Fariba Némati, André Nicolas, Bruno Tesson, Laurence Desjardins, Pascale Mariani, Audrey Rapinat, Xavier Sastre-Garau, Jérôme Couturier, Philippe Hupé, Leanne de Koning, Thierry Dubois, Sergio Roman-Roman, Marc-Henri Stern, Emmanuel Barillot, J William Harbour, Simon Saule, Didier Decaudin (2013 Mar 13)

Patient-derived xenografts recapitulate molecular features of human uveal melanomas.

Molecular oncology : 625-36 : DOI : 10.1016/j.molonc.2013.02.004 En savoir plus
Résumé

We have previously developed a new method for the development and maintenance of uveal melanoma (UM) xenografts in immunodeficient mice. Here, we compare the genetic profiles of the primary tumors to their corresponding xenografts that have been passaged over time. The study included sixteen primary UMs and corresponding xenografts at very early (P1), early (P4), and late (P9) in vivo passages. The tumors were analyzed for mutation status of GNAQ, GNA11, GNAS, GNA15, BAP1, and BRAF, chromosomal copy number alterations using Affymetrix GeneChip(®) Genome-Wide Human SNP6.0 arrays, gene expression profiles using GeneChip(®) Human Exon 1.0 ST arrays, BAP1 mRNA and protein expression, and MAPK pathway status using Reverse Phase Protein Arrays (RPPA). The UM xenografts accurately recapitulated the genetic features of primary human UMs and they exhibited genetic stability over the course of their in vivo maintenance. Our technique for establishing and maintaining primary UMs as xenograft tumors in immunodeficient mice exhibit a high degree of genetic conservation between the primary tumors and the xenograft tumors over multiple passages in vivo. These models therefore constitute valuable preclinical tool for drug screening in UM.

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Asma Tlili, Frank Jacobs, Leanne de Koning, Sirine Mohamed, Linh-Chi Bui, Julien Dairou, Nicole Belin, Véronique Ducros, Thierry Dubois, Jean-Louis Paul, Jean-Maurice Delabar, Bart De Geest, Nathalie Janel (2013 Feb 23)

Hepatocyte-specific Dyrk1a gene transfer rescues plasma apolipoprotein A-I levels and aortic Akt/GSK3 pathways in hyperhomocysteinemic mice.

Biochimica et biophysica acta : 718-28 : DOI : 10.1016/j.bbadis.2013.02.008 En savoir plus
Résumé

Hyperhomocysteinemia, characterized by high plasma homocysteine levels, is recognized as an independent risk factor for cardiovascular diseases. The increased synthesis of homocysteine, a product of methionine metabolism involving B vitamins, and its slower intracellular utilization cause increased flux into the blood. Plasma homocysteine level is an important reflection of hepatic methionine metabolism and the rate of processes modified by B vitamins as well as different enzyme activity. Lowering homocysteine might offer therapeutic benefits. However, approximately 50% of hyperhomocysteinemic patients due to cystathionine-beta-synthase deficiency are biochemically responsive to pharmacological doses of B vitamins. Therefore, effective treatments to reduce homocysteine levels are needed, and gene therapy could provide a novel approach. We recently showed that hepatic expression of DYRK1A, a serine/threonine kinase, is negatively correlated with plasma homocysteine levels in cystathionine-beta-synthase deficient mice, a mouse model of hyperhomocysteinemia. Therefore, Dyrk1a is a good candidate for gene therapy to normalize homocysteine levels. We then used an adenoviral construct designed to restrict expression of DYRK1A to hepatocytes, and found decreased plasma homocysteine levels after hepatocyte-specific Dyrk1a gene transfer in hyperhomocysteinemic mice. The elevation of pyridoxal phosphate was consistent with the increase in cystathionine-beta-synthase activity. Commensurate with the decreased plasma homocysteine levels, targeted hepatic expression of DYRK1A resulted in elevated plasma paraoxonase-1 activity and apolipoprotein A-I levels, and rescued the Akt/GSK3 signaling pathways in aorta of mice, which can prevent homocysteine-induced endothelial dysfunction. These results demonstrate that hepatocyte-restricted Dyrk1a gene transfer can offer a useful therapeutic targets for the development of new selective homocysteine lowering therapy.

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Année de publication : 2012

Virginie Maire, Fariba Némati, Marion Richardson, Anne Vincent-Salomon, Bruno Tesson, Guillem Rigaill, Eléonore Gravier, Bérengère Marty-Prouvost, Leanne De Koning, Guillaume Lang, David Gentien, Aurélie Dumont, Emmanuel Barillot, Elisabetta Marangoni, Didier Decaudin, Sergio Roman-Roman, Alain Pierré, Francisco Cruzalegui, Stéphane Depil, Gordon C Tucker, Thierry Dubois (2012 Nov 13)

Polo-like kinase 1: a potential therapeutic option in combination with conventional chemotherapy for the management of patients with triple-negative breast cancer.

Cancer research : 813-23 : DOI : 10.1158/0008-5472.CAN-12-2633 En savoir plus
Résumé

Breast cancers are composed of molecularly distinct subtypes with different clinical outcomes and responses to therapy. To discover potential therapeutic targets for the poor prognosis-associated triple-negative breast cancer (TNBC), gene expression profiling was carried out on a cohort of 130 breast cancer samples. Polo-like kinase 1 (PLK1) was found to be significantly overexpressed in TNBC compared with the other breast cancer subtypes. High PLK1 expression was confirmed by reverse phase protein and tissue microarrays. In triple-negative cell lines, RNAi-mediated PLK1 depletion or inhibition of PLK1 activity with a small molecule (BI-2536) induced an increase in phosphorylated H2AX, G(2)-M arrest, and apoptosis. A soft-agar colony assay showed that PLK1 silencing impaired clonogenic potential of TNBC cell lines. When cells were grown in extracellular matrix gels (Matrigel), and exposed to BI-2536, apoptosis was observed specifically in TNBC cancerous cells, and not in a normal cell line. When administrated as a single agent, the PLK1 inhibitor significantly impaired tumor growth in vivo in two xenografts models established from biopsies of patients with TNBC. Most importantly, the administration of BI-2536, in combination with doxorubicin + cyclophosphamide chemotherapy, led to a faster complete response compared with the chemotherapy treatment alone and prevented relapse, which is the major risk associated with TNBC. Altogether, our observations suggest PLK1 inhibition as an attractive therapeutic approach, in association with conventional chemotherapy, for the management of patients with TNBC.

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Sylvie Troncale, Aurélie Barbet, Lamine Coulibaly, Emilie Henry, Beilei He, Emmanuel Barillot, Thierry Dubois, Philippe Hupé, Leanne de Koning (2012 Jul 5)

NormaCurve: a SuperCurve-based method that simultaneously quantifies and normalizes reverse phase protein array data.

PloS one : e38686 : DOI : 10.1371/journal.pone.0038686 En savoir plus
Résumé

Reverse phase protein array (RPPA) is a powerful dot-blot technology that allows studying protein expression levels as well as post-translational modifications in a large number of samples simultaneously. Yet, correct interpretation of RPPA data has remained a major challenge for its broad-scale application and its translation into clinical research. Satisfying quantification tools are available to assess a relative protein expression level from a serial dilution curve. However, appropriate tools allowing the normalization of the data for external sources of variation are currently missing.

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