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ABSTRACT: The Wnt/β-catenin pathway plays a crucial role in the pathogenesis of various human cancers. In multiple myeloma (MM), aberrant auto-and/or paracrine activation of canonical Wnt signaling promotes proliferation and dissemination, while overexpression of the Wnt inhibitor Dickkopf1 (DKK1) by MM cells contributes to osteolytic bone disease by inhibiting osteoblast differentiation. Since DKK1 itself is a target of TCF/β-catenin mediated transcription, these findings suggest that DKK1 is part of a negative feedback loop in MM and may act as a tumor suppressor. In line with this hypothesis, we show here that DKK1 expression is low or undetectable in a subset of patients with advanced MM as well as in MM cell lines. This absence of DKK1 is correlated with enhanced Wnt pathway activation, evidenced by nuclear accumulation of β-catenin, which in turn can be antagonized by restoring DKK1 expression. Analysis of the DKK1 promoter revealed CpG island methylation in several MM cell lines as well as in MM cells from patients with advanced MM. Moreover, demethylation of the DKK1 promoter restores DKK1 expression, which results in inhibition of β-catenin/TCF-mediated gene transcription in MM lines. Taken together, our data identify aberrant methylation of the DKK1 promoter as a cause of DKK1 silencing in advanced stage MM, which may play an important role in the progression of MM by unleashing Wnt signaling.
PLoS ONE 01/2012; 7(2):e30359. · 4.09 Impact Factor
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ABSTRACT: Hepatocyte growth factor (HGF) and its receptor MET are essential during embryonic development and throughout postnatal life. However, aberrant MET activation, due to overexpression, mutations, or autocrine ligand production, contributes to the development and progression of a variety of human cancers, often being associated with poor clinical outcome and drug resistance. B cell malignancies arise from B cells that are clonally expanded at different stages of differentiation. Despite major therapeutic advances, most mature B cell malignancies remain incurable and biologically-oriented therapeutic strategies are urgently needed. This review addresses the role of the HGF/MET pathway during B cell development and discusses how its aberrant activation contributes to the development of B cell lymphoproliferative disorders, with particular emphasis on multiple myeloma and diffuse large B cell lymphoma. These insights, combined with the recent development of clinical-grade agents targeting the MET pathway, provide the rationale to envision the HGF/MET pathway as a new promising target for the treatment of B cell malignancies.
Biochimica et Biophysica Acta 12/2010; 1806(2):208-19. · 4.66 Impact Factor
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ABSTRACT: Multiple myeloma (MM) is characterized by a strong dependence of the tumor cells on their microenvironment, which produces growth factors supporting survival and proliferation of myeloma cells (MMC). In the past few years, many myeloma growth factors (MGF) have been described in the literature. However, their relative importance and the nature of the cells producing MGF remain unidentified for many of them.
We have analysed the expression of 51 MGF and 36 MGF receptors (MGFR) using Affymetrix microarrays throughout normal plasma cell differentiation, in MMC and in cells from the bone marrow (BM) microenvironment (CD14, CD3, polymorphonuclear neutrophils, stromal cells and osteoclasts).
4/51 MGF and 9/36 MGF-receptors genes were significantly overexpressed in plasmablasts (PPC) and BM plasma cell (BMPC) compared to B cells whereas 11 MGF and 11 MGFR genes were overexpressed in BMPC compared to PPC. 3 MGF genes (AREG, NRG3, Wnt5A) and none of the receptors were significantly overexpressed in MMC versus BMPC. Furthermore, 3/51 MGF genes were overexpressed in MMC compared to the the BM microenvironment whereas 22/51 MGF genes were overexpressed in one environment subpopulation compared to MMC.
Two major messages arise from this analysis 1) The majority of MGF genes is expressed by the bone marrow environment. 2) Several MGF and their receptors are overexpressed throughout normal plasma cell differentiation. This study provides an extensive and comparative analysis of MGF expression in plasma cell differentiation and in MM and gives new insights in the understanding of intercellular communication signals in MM.
BMC Cancer 01/2010; 10:198. · 3.01 Impact Factor
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Jérôme Moreaux,
Anne-Catherine Sprynski,
Stacey R Dillon, Karène Mahtouk,
Michel Jourdan,
Arnaud Ythier,
Philippe Moine,
Nicolas Robert,
Eric Jourdan,
Jean François Rossi,
Bernard Klein
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ABSTRACT: BLyS and APRIL share two receptors - transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and B-cell maturation antigen (BCMA) - and BLyS binds to a third receptor, BAFF-R. We previously reported that TACI gene expression is a good indicator of a BLyS-binding receptor in human multiple myeloma cell lines (HMCLs), unlike BCMA, which is expressed by all HMCLs or BAFF-R which is typically not expressed by late-stage B cells. We hypothesised a link between APRIL and TACI through syndecan-1, similar to the situation reported for FGF and FGFR. We observed very strong binding of APRIL, but not BLyS, at the surface of all syndecan-1(+) HMCLs and primary multiple myeloma cells (MMC). All syndecan-1(+) HMCLs and MMC could also bind TACI-Fc, but not BCMA-Fc or BAFF-R-Fc molecules. Binding of APRIL or TACI-Fc was abrogated by heparin or cell pretreatment with heparitinase, which cleaves heparan sulfate chains. The growth factor activity of APRIL on MMC was also inhibited by heparin. Our data identify syndecan-1 as a co-receptor for APRIL and TACI at the cell surface of MMC, promoting the activation of an APRIL/TACI pathway that induces survival and proliferation in MMC.
European Journal Of Haematology 05/2009; 83(2):119-29. · 2.61 Impact Factor
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ABSTRACT: Syndecan-1 is a proteoglycan that concentrates heparin-binding factors on the surface of multiple myeloma cells, and probably plays a major role in multiple myeloma biology. As heparan sulphate and chondroitin sulphate are the bioactive components of syndecan-1, we analysed the signature of genes encoding 100 proteins involved in synthesis of these chains, i.e. from precursor uptake to post-translational modifications, using Affymetrix microarrays. The expression of enzymes required for heparan sulphate and chondroitin sulphate biosynthesis was shown to increase in parallel with syndecan-1 expression, throughout the differentiation of memory B cells into plasmablasts and normal bone marrow plasma cells. Sixteen genes were significantly different between normal and malignant plasma cells, nine of these genes -EXT2, CHSY3, CSGALNACT1, HS3ST2, HS2ST1, CHST11, CSGALNACT2, HPSE, SULF2 - encode proteins involved in glycosaminoglycan chain synthesis or modifications. Kaplan-Meier analysis was performed in two independent series of patients: B4GALT7, CSGALNACT1, HS2ST1 were associated with a good prognosis whereas EXT1 was linked to a bad prognosis. This study provides an overall picture of the major genes encoding for proteins involved in heparan sulphate and chondroitin sulphate synthesis and modifications that can be implicated in normal and malignant plasma cells.
British Journal of Haematology 03/2009; 145(3):350-68. · 4.94 Impact Factor
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ABSTRACT: Multiple myeloma is a B-cell neoplasia characterized by the proliferation of a clone of malignant plasma cells in the bone marrow. We review here the input of gene expression profiling of myeloma cells and of their tumor microenvironment to develop new tumor classifiers, to better understand the biology of myeloma cells, to identify some mechanisms of drug sensitivity and resistance, to identify new myeloma growth factors, and to depict the complex interactions between tumor cells and their microenvironment. We discuss how these findings may improve the clinical outcome of this still incurable disease.
Clinical Cancer Research 01/2008; 13(24):7289-95. · 7.74 Impact Factor
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Michel Jourdan,
Jérôme Moreaux,
John De Vos,
Dirk Hose, Karène Mahtouk,
Matthieu Abouladze,
Nicolas Robert,
Marion Baudard,
Thierry Rème,
Angela Romanelli,
Hartmut Goldschmidt,
Jean-François Rossi,
Michel Dreano,
Bernard Klein
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ABSTRACT: The pathophysiologic basis for multiple myeloma (MM) has been attributed to the dysregulation of various paracrine or autocrine growth factor loops and to perturbations in several signal transduction pathways including IkappaB kinase/nuclear factor-kappaB (IKK/NF-kappaB). The present study aimed at investigating the effect of a pharmaceutical IKK2 inhibitor, the anilinopyrimidine derivative AS602868, on the in vitro growth of 14 human MM cell lines (HMCL) and primary cells from 13 patients. AS602868 induced a clear dose-dependent inhibition of MM cell growth on both HMCL and primary MM cells, which was the result of a simultaneous induction of apoptosis and inhibition of the cell cycle progression. Combination of AS602868 with suboptimal doses of melphalan or Velcade showed an additive effect in growth inhibition of HMCL. AS602868 also induced apoptosis of primary myeloma cells. Importantly, AS602868 did not alter the survival of other bone marrow mononuclear cells (CD138(-)) co-cultured with primary MM (CD138(+)) cells, except for CD34(+) haematopoietic stem cells. The results demonstrate the important role of NF-kappaB in maintaining the survival of MM cells and suggest that a pharmacological inhibition of the NF-kappaB pathway by the IKK2 inhibitor AS602868 can efficiently kill HMCL and primary myeloma cells and therefore might represent an innovative approach for treating MM patients.
British Journal of Haematology 08/2007; 138(2):160-8. · 4.94 Impact Factor
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Karène Mahtouk,
Dirk Hose,
Pierre Raynaud,
Michael Hundemer,
Michel Jourdan,
Eric Jourdan,
Veronique Pantesco,
Marion Baudard,
John De Vos,
Marion Larroque,
Thomas Moehler,
Jean-Francois Rossi,
Thierry Rème,
Hartmut Goldschmidt,
Bernard Klein
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ABSTRACT: The heparan sulfate (HS) proteoglycan, syndecan-1, plays a major role in multiple myeloma (MM) by concentrating heparin-binding growth factors on the surface of MM cells (MMCs). Using Affymetrix microarrays and real-time reverse transcriptase-polymerase chain reaction (RT-PCR), we show that the gene encoding heparanase (HPSE), an enzyme that cleaves HS chains, is expressed by 11 of 19 myeloma cell lines (HMCLs). In HSPE(pos) HMCLs, syndecan-1 gene expression and production of soluble syndecan-1, unlike expression of membrane syndecan-1, were significantly increased. Knockdown of HPSE by siRNA resulted in a decrease of syndecan-1 gene expression and soluble syndecan-1 production without affecting membrane syndecan-1 expression. Thus, HPSE influences expression and shedding of syndecan-1. Contrary to HMCLs, HPSE is expressed in only 4 of 39 primary MMC samples, whereas it is expressed in 36 of 39 bone marrow (BM) microenvironment samples. In the latter, HPSE is expressed at a median level in polymorphonuclear cells and T cells; it is highly expressed in monocytes and osteoclasts. Affymetrix data were validated at the protein level, both on HMCLs and patient samples. We report for the first time that a gene's expression mainly in the BM environment (ie, HSPE) is associated with a shorter event-free survival of patients with newly diagnosed myeloma treated with high-dose chemotherapy and stem cell transplantation. Our study suggests that clinical inhibitors of HPSE could be beneficial for patients with MM.
Blood 07/2007; 109(11):4914-23. · 9.90 Impact Factor
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Jill Corre, Karène Mahtouk,
Michel Attal,
Mélanie Gadelorge,
Anne Huynh,
Sandrine Fleury-Cappellesso,
Clotaire Danho,
Patrick Laharrague,
Bernard Klein,
Thierry Rème,
Philippe Bourin
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ABSTRACT: Recent literature suggested that cells of the microenvironment of tumors could be abnormal as well. To address this hypothesis in multiple myeloma (MM), we studied bone marrow mesenchymal stem cells (BMMSCs), the only long-lived cells of the bone marrow microenvironment, by gene expression profiling and phenotypic and functional studies in three groups of individuals: patients with MM, patients with monoclonal gamopathy of undefined significance (MGUS) and healthy age-matched subjects. Gene expression profile independently classified the BMMSCs of these individuals in a normal and in an MM group. MGUS BMMSCs were interspersed between these two groups. Among the 145 distinct genes differentially expressed in MM and normal BMMSCs, 46% may account for a tumor-microenvironment cross-talk. Known soluble factors implicated in MM pathophysiologic features (i.e. IL (interleukin)-6, DKK1) were revealed and new ones were found which are involved in angiogenesis, osteogenic differentiation or tumor growth. In particular, GDF15 was found to induce dose-dependent growth of MOLP-6, a stromal cell-dependent myeloma cell line. Functionally, MM BMMSCs induced an overgrowth of MOLP-6, and their capacity to differentiate into an osteoblastic lineage was impaired. Thus, MM BMMSCs are abnormal and could create a very efficient niche to support the survival and proliferation of the myeloma cells.
Leukemia 06/2007; · 9.56 Impact Factor
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Karène Mahtouk,
Friedrich Cremer,
Thierry Rème,
Michel Jourdan,
Marion Baudard,
Jérome Moreaux,
Guilhem Requirand,
Geneviève Fiol,
John De Vos,
Marion Moos,
Philippe Quittet,
Hartmut Goldschmidt,
Jean-François Rossi,
Dirk Hose,
Bernard Klein
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ABSTRACT: The epidermal growth factor (EGF)/EGF-receptor (ErbB1-4) family is involved in the biology of multiple myeloma (MM). In particular, ErbB-specific inhibitors induce strong apoptosis of myeloma cells (MMC) in vitro. To delineate the contribution of the 10 EGF-family ligands to the pathogenesis of MM, we have assessed their expression and biological activity. Comparing Affymetrix DNA-microarray-expression-profiles of CD138-purified plasma-cells from 65 MM-patients and 7 normal individuals to those of plasmablasts and B-cells, we found 5/10 EGF-family genes to be expressed in MMC. Neuregulin-2 and neuregulin-3 were expressed by MMC only, while neuregulin-1, amphiregulin and transforming growth factor-alpha were expressed by both MMC and normal plasma-cells. Using real-time polymerase chain reaction, we found HB-EGF, amphiregulin, neuregulin-1 and epiregulin to be expressed by cells from the bone marrow-environment. Only the EGF-members able to bind heparan-sulphate proteoglycans (HSPGs) - neuregulin-1, amphiregulin, HB-EGF - promote the growth of MMC. Those ligands strongly bind MMC through HSPGs. The binding and the MMC growth activity was abrogated by heparitinase, heparin or deletion of the HS-binding domain. The number of HS-binding EGF ligand molecules bound to MMC was higher than 10(5) molecules/cell and paralleled that of syndecan-1. Syndecan-1, the main HSPG present on MM cells, likely concentrates high levels of HS-binding-EGF-ligands at the cell membrane and facilitates ErbB-activation. Altogether, our data further identify EGF-signalling as promising target for MM-therapy.
Oncogene 12/2006; · 6.37 Impact Factor
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Karène Mahtouk,
Dirk Hose,
Thierry Rème,
John De Vos,
Michel Jourdan,
Jérôme Moreaux,
Geneviève Fiol,
Marc Raab,
Eric Jourdan,
Véronique Grau,
Marion Moos,
Hartmut Goldschmidt,
Marion Baudard,
Jean François Rossi,
Friedrich W Cremer,
Bernard Klein
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ABSTRACT: A hallmark of plasma cells is the expression of syndecan-1, which has major functions in epithelial cells, in particular as the coreceptor of heparin-binding growth factors. We previously found that heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a growth factor for malignant plasma cells. As amphiregulin (AREG) is another heparin-binding factor of the EGF family, we investigated its role in multiple myeloma (MM). Using Affymetrix DNA microarrays, we show here that the AREG gene was expressed by purified primary myeloma cells from 65 patients and that the expression was higher than in normal bone marrow (BM) plasma cells or plasmablastic cells. AREG stimulated IL-6 production and growth of BM stromal cells. Using real-time reverse transcriptase-polymerase chain reaction, we found that MM cells expressed ErbB receptors and that AREG promoted their growth. Furthermore, PD169540 (a pan-ErbB inhibitor) and IRESSA (an ErbB1-specific inhibitor) induced apoptosis of primary myeloma cells from 10/14 and 4/14 patients, respectively, and there was a synergistic effect with dexamethasone. Altogether, our data provide strong evidence that AREG plays an important role in the biology of MM and emphasize the advantages of using ErbB inhibitors, which might target myeloma cells as well as the tumor environment.
Oncogene 06/2005; 24(21):3512-24. · 6.37 Impact Factor
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ABSTRACT: We previously found that some myeloma cell lines express the heparin-binding epidermal growth factor-like growth factor (HB-EGF) gene. As the proteoglycan syndecan-1 is an HB-EGF coreceptor as well as a hallmark of plasma cell differentiation and a marker of myeloma cells, we studied the role of HB-EGF on myeloma cell growth. The HB-EGF gene was expressed by bone marrow mononuclear cells in 8 of 8 patients with myeloma, particularly by monocytes and stromal cells, but not by purified primary myeloma cells. Six of 9 myeloma cell lines and 9 of 9 purified primary myeloma cells expressed ErbB1 or ErbB4 genes coding for HB-EGF receptor. In the presence of a low interleukin-6 (IL-6) concentration, HB-EGF stimulated the proliferation of the 6 ErbB1+ or ErbB4+ cell lines, through the phosphatidylinositol 3-kinase/AKT (PI-3K/AKT) pathway. A pan-ErbB inhibitor blocked the myeloma cell growth factor activity and the signaling induced by HB-EGF. This inhibitor induced apoptosis of patients'myeloma cells cultured with their tumor environment. It also increased patients' myeloma cell apoptosis induced by an anti-IL-6 antibody or dexamethasone. The ErbB inhibitor had no effect on the interaction between multiple myeloma cells and stromal cells. It was not toxic for nonmyeloma cells present in patients' bone marrow cultures or for the growth of hematopoietic progenitors. Altogether, these data identify ErbB receptors as putative therapeutic targets in multiple myeloma.
Blood 04/2004; 103(5):1829-37. · 9.90 Impact Factor
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ABSTRACT: Primary myeloma cells rapidly apoptose as soon as they are removed from their bone-marrow environment. A likely explanation is that the tumor environment produces survival factors that may counteract a spontaneous activation of pro-apoptotic program. Additional factors may trigger cell cycling in surviving myeloma cells. Interleukin-6 (IL-6) is a well recognized myeloma cell growth factor produced mainly by the tumor environment. However, myeloma cells themselves may produce low levels of autocrine IL-6. The respective roles of paracrine versus autocrine IL-6 are a matter of debate. We investigated these roles using the XG-6 myeloma cell line whose growth is dependent on addition of exogenous IL-6, despite its weak IL-6 mRNA and protein expression. The apoptosis induced by exogenous IL-6 deprivation was blocked by transferring the Mcl-1 gene coding for an anti-apoptotic protein in XG-6 cells. An XG-6Mcl-1 cell line which can survive and grow without adding IL-6 was obtained. We show that anti-IL-6 or anti-gp130 antibodies abrogated cell cycling whereas they did not affect cell survival. These data indicate that the weak autocrine IL-6 produced by myeloma cells is sufficient to trigger cell cycling whereas their survival requires large exogenous IL-6 concentrations. This important role of autocrine IL-6 has to be considered when evaluating the mechanism of action of myeloma cell growth factors. These factors may actually block an activated pro-apoptotic program, making possible a weak production of autocrine IL-6 to promote cell cycling.
European cytokine network 16(1):57-64. · 1.73 Impact Factor
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ABSTRACT: Hepatocyte growth factor (HGF) and its receptor MET are essential during embryonic development and throughout postnatal life. However, aberrant MET activation, due to overexpression, mutations, or autocrine ligand production, contributes to the development and progression of a variety of human cancers, often being associated with poor clinical outcome and drug resistance. B cell malignancies arise from B cells that are clonally expanded at different stages of differentiation. Despite major therapeutic advances, most mature B cell malignancies remain incurable and biologically-oriented therapeutic strategies are urgently needed. This review addresses the role of the HGF/MET pathway during B cell development and discusses how its aberrant activation contributes to the development of B cell lymphoproliferative disorders, with particular emphasis on multiple myeloma and diffuse large B cell lymphoma. These insights, combined with the recent development of clinical-grade agents targeting the MET pathway, provide the rationale to envision the HGF/MET pathway as a new promising target for the treatment of B cell malignancies.
Biochimica et Biophysica Acta (BBA) - Reviews on Cancer.
