C. Come | University of Copenhagen (original) (raw)

Papers by C. Come

Research paper thumbnail of In Vivo Imaging of Luminescent Diffuse Large B-Cell Lymphoma Xenografts Combined with Mass Spectrometry Imaging Identify Specific Molecular Alteration During R-Chop Relapse

Haematologica-the Hematology Journal, 2017

Research paper thumbnail of CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

PloS one, 2016

The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most ma... more The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell...

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Twist, a Master Regulator of Morphogenesis, Plays an Essential Role in Tumor Metastasis

Cell, 2004

The first step-invasion-requires neoplastic epithelial 1 Whitehead Institute for Biomedical Resea... more The first step-invasion-requires neoplastic epithelial 1 Whitehead Institute for Biomedical Research cells to lose cell-cell adhesion and to gain motility, which 9 Cambridge Center enables them to invade the adjacent tissue. During the Cambridge, Massachusetts 02142 second step, intravasation, tumor cells penetrate 2 Cancer Genomics Program through the endothelium of blood or lymphatic vessels Broad Institute to enter the systemic circulation. Only some circulating Cambridge, Massachusetts 02141 tumor cells appear to be able to survive the passage 3 MGH Center for Cancer Research through circulation. Some of these survivors manage to Charlestown, Massachusetts 02129 complete the next step-extravasation-as they extrav-4 Ecole Normale Superieure asate through the capillary endothelium at distal sites. 75230 Paris Cedex 05 Finally, in the new host environment, an even smaller France subset of such metastasizing cells succeeds in prolifer-5 EMI 0229 INSERM ating from minute growths (micrometastases) into malig-CRLC Val d'Aurelle-Paul Lamarque nant, secondary tumors (Fidler, 2003). A central aim in 34298 Montpellier Cedex 5 the study of tumor metastasis is to understand the na-France ture of the distinct genetic and epigenetic changes that 6 Department of Molecular Genetics & Development program these individual steps. Ben Gurion University of the Negev Recently, our understanding of metastasis has been Beer Sheva 84105 expanded through microarray analyses of various hu-Israel man tumor samples. For example, several studies of 7 Department of Pathology human primary breast tumors have generated gene ex-Brigham and Women's Hospital pression profiles that are predictive of metastasis or Harvard Medical School poor survival rate (Ramaswamy et al., 2003; van't Veer et Boston, Massachusetts 02115 al., 2002). Such analyses are very powerful for producing fingerprints of metastatic tumor cells, which could be used as prognostic markers of metastatic diseases. However, due to the lack of further experimental manip-Summary ulation of human tumor samples, it has been very difficult to elucidate the specific contributions of such genes to Metastasis is a multistep process during which cancer tumor metastasis. cells disseminate from the site of primary tumors and Experimental animal models have been successfully establish secondary tumors in distant organs. In a used to identify molecular elements during metastasis. search for key regulators of metastasis in a murine For example, in an expression profile analysis comparbreast tumor model, we have found that the transcriping melanoma cells and their highly metastatic derivation factor Twist, a master regulator of embryonic mortives, RhoC was identified as essential for pulmonary phogenesis, plays an essential role in metastasis. Supmetastasis by melanoma cells that were injected intrapression of Twist expression in highly metastatic venously into mice (Clark et al., 2000). Recently, a set mammary carcinoma cells specifically inhibits their of genes, including osteopontin and IL-11, were shown ability to metastasize from the mammary gland to the to promote bone metastasis when human breast cancer lung. Ectopic expression of Twist results in loss of cells were injected via the intracardiac route (Kang et E-cadherin-mediated cell-cell adhesion, activation of al., 2003). Most of these models rely on the introduction mesenchymal markers, and induction of cell motility, of tumor cells directly into the systemic circulation. Such suggesting that Twist contributes to metastasis by approaches obviate the steps of invasion and intravasapromoting an epithelial-mesenchymal transition (EMT). tion and therefore are unlikely to reveal genes involved In human breast cancers, high level of Twist expresin these early steps of metastasis. sion is correlated with invasive lobular carcinoma, a Given the complexity of the process of metastasis, it highly infiltrating tumor type associated with loss of is essential to exploit experimental models in which each E-cadherin expression. These results establish a of the steps of metastasis is represented and can be mechanistic link between Twist, EMT, and tumor memanipulated individually. In this report, we exploit a tastasis. mouse mammary tumor model, in which a set of otherwise isogenic tumor cell populations is able to complete distinct steps of metastasis when implanted into the

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

• Loss of Prdm11 accelerates MYC-driven lymphomagenesis. • PRDM11 regulates transcription of targ... more • Loss of Prdm11 accelerates MYC-driven lymphomagenesis. • PRDM11 regulates transcription of target genes, including FOS and JUN. The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Em-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Research paper thumbnail of 284 Slug Controls P-cadherin and Regulates Stem/progenitor Cell Dynamics During Mammary Gland Morphogenesis

European Journal of Cancer, 2012

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are der... more The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Twist, a master regulator of morphogenesis, plays an essential role in tumor metastasis

Cell, Jan 1, 2004

Metastasis is a multistep process during which cancer cells disseminate from the site of primary ... more Metastasis is a multistep process during which cancer cells disseminate from the site of primary tumors and establish secondary tumors in distant organs. In a search for key regulators of metastasis in a murine breast tumor model, we have found that the transcription factor Twist, a master regulator of embryonic morphogenesis, plays an essential role in metastasis. Suppression of Twist expression in highly metastatic mammary carcinoma cells specifically inhibits their ability to metastasize from the mammary gland to the lung. Ectopic expression of Twist results in loss of E-cadherin-mediated cell-cell adhesion, activation of mesenchymal markers, and induction of cell motility, suggesting that Twist contributes to metastasis by promoting an epithelial-mesenchymal transition (EMT). In human breast cancers, high level of Twist expression is correlated with invasive lobular carcinoma, a highly infiltrating tumor type associated with loss of E-cadherin expression. These results establish a mechanistic link between Twist, EMT, and tumor metastasis.

Research paper thumbnail of CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most ma... more The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2A HOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2A HOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4 + T-cells and CD8 + effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we

Research paper thumbnail of Senescence sensitivity of breast cancer cells is defined by positive feedback loop between CIP2A and E2F1

Cancer discovery, 2013

Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumo... more Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumor suppression. However, whether p53 inactivation actively suppresses senescence induction has been unclear. Here, we show that E2F1 overexpression, due to p53 or p21 inactivation, promotes expression of human oncoprotein CIP2A, which in turn, by inhibiting PP2A activity, increases stabilizing serine 364 phosphorylation of E2F1. Several lines of evidence show that increased activity of E2F1-CIP2A feedback renders breast cancer cells resistant to senescence induction. Importantly, mammary tumorigenesis is impaired in a CIP2A-deficient mouse model, and CIP2A-deficient tumors display markers of senescence induction. Moreover, high CIP2A expression predicts for poor prognosis in a subgroup of patients with breast cancer treated with senescence-inducing chemotherapy. Together, these results implicate the E2F1-CIP2A feedback loop as a key determinant of breast cancer cell sensitivity to senesce...

Research paper thumbnail of CIP2A Promotes Proliferation of Spermatogonial Progenitor Cells and Spermatogenesis in Mice

PLoS ONE, 2012

Protein phosphatase 2A (PP2A) is a critical regulator of protein serine/threonine phosphorylation... more Protein phosphatase 2A (PP2A) is a critical regulator of protein serine/threonine phosphorylation. However, the physiological and developmental roles of different PP2A complexes are very poorly understood. Here, we show that a newly characterized PP2A inhibitory protein CIP2A is co-expressed with ki-67 and with self-renewal protein PLZF in the spermatogonial progenitor cell (SPC) population in the testis. CIP2A and PLZF expression was shown also to correlate Ki-67 expression in human testicular spermatogonia. Functionally, CIP2A mutant mouse testes exhibited smaller number of PLZFpositive SPCs and reduced sperm counts. Moreover, seminiferous tubuli cells isolated from CIP2A mutant mice showed reduced expression of Plzf and other renewal genes Oct-4 and Nanog at mRNA level. However, PLZF-deficient testes did not show altered CIP2A expression. Importantly, spermatogonia-specific restoration of CIP2A expression rescued PLZF expression and sperm production defects observed in CIP2A mutant mice. Taken together, these results reveal first physiological function for an emerging human oncoprotein CIP2A, and provide insights into maintenance of PLZF-positive progenitors. Moreover, demonstration that CIP2A expression can be systematically inhibited without severe consequences to normal mouse development and viability may have clinical relevance regarding targeting of oncogenic CIP2A for future cancer therapies.

Research paper thumbnail of CIP2A Is Associated with Human Breast Cancer Aggressivity

Clinical Cancer Research, 2009

Purpose: To investigate the clinical relevance of the recently characterized human oncoprotein ca... more Purpose: To investigate the clinical relevance of the recently characterized human oncoprotein cancerous inhibitor of protein phosphatase 2A (CIP2A) in human breast cancer. Experimental Design: CIP2A expression (mRNA and protein) was measured in three different sets of human mammary tumors and compared with clinicopathologic variables. The functional role of CIP2A in breast cancer cells was evaluated by small interfering RNA-mediated depletion of the protein followed by an analysis of cell proliferation, migration, anchorage-independent growth, and xenograft growth. Results: CIP2A mRNA is overexpressed (n = 159) and correlates with higher Scarff-Bloom-Richardson grades (n = 251) in samples from two independent human breast cancer patients. CIP2A protein was found to be overexpressed in 39% of 33 human breast cancer samples. Furthermore, CIP2A mRNA expression positively correlated with lymph node positivity of the patients and with the expression of proliferation markers and p53 mutations in the tumor samples. Moreover, CIP2A protein expression was induced in breast cancer mouse models presenting mammary gland-specific depletion of p53 and either BRCA1 or BRCA2. Functionally, CIP2A depletion was shown to inhibit the expression of its target protein c-Myc. Loss of CIP2A also inhibited anchorageindependent growth in breast cancer cells. Finally, CIP2A was shown to support MDA-MB-231 xenograft growth in nude mice. Conclusions: Our data show that CIP2A is associated with clinical aggressivity in human breast cancer and promotes the malignant growth of breast cancer cells. Thus, these results validate the role of CIP2A as a clinically relevant human oncoprotein and warrant further investigation of CIP2A as a therapeutic target in breast cancer treatment. (Clin Cancer Res 2009;15(16):5092-100)

Research paper thumbnail of Snail and Slug Play Distinct Roles during Breast Carcinoma Progression

Clinical Cancer Research, 2006

Carcinoma progression is linked to a partially dedifferentiated epithelial cell phenotype. As pre... more Carcinoma progression is linked to a partially dedifferentiated epithelial cell phenotype. As previously suggested, this regulation could involve transcription factors, Snail and Slug, known to promote epithelial-mesenchymal transitions during development. Here, we investigate the role of Snail and Slug in human breast cancer progression. We analyzed Snail, Slug, and E-cadherin RNA expression levels and protein localization in large numbers of transformed cell lines and breast carcinomas, examined the correlation with tumor histologic features, and described, at the cellular level, Snail and Slug localization in carcinomas using combined in situ hybridization and immunolocalization. In contrast with transformed cell lines, Slug was found to colocalize with E-cadherin at the cellular level in normal mammary epithelial cells and all tested carcinomas. Snail also colocalized at the cellular level with E-cadherin in tumors expressing high levels of Snail RNA. In addition, Snail was significantly expressed in tumor stroma, varying with tumors. Slug and Snail genes were significantly overexpressed in tumors associated with lymph node metastasis. Finally, the presence of semidifferentiated tubules within ductal carcinomas was linked to Slug expression levels similar to or above normal breast samples. These results suggest that Snail or Slug expression in carcinoma cells does not generally preclude significant E-cadherin expression. They emphasize a link between Snail, Slug, and lymph node metastasis in a large sampling of mammary carcinomas, and suggest a role for Slug in the maintenance of semidifferentiated structures. Snail and Slug proteins seem to support distinct tumor invasion modes and could provide new therapeutic targets.

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are der... more The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Research paper thumbnail of In Vivo Imaging of Luminescent Diffuse Large B-Cell Lymphoma Xenografts Combined with Mass Spectrometry Imaging Identify Specific Molecular Alteration During R-Chop Relapse

Haematologica-the Hematology Journal, 2017

Research paper thumbnail of CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

PloS one, 2016

The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most ma... more The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell...

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Twist, a Master Regulator of Morphogenesis, Plays an Essential Role in Tumor Metastasis

Cell, 2004

The first step-invasion-requires neoplastic epithelial 1 Whitehead Institute for Biomedical Resea... more The first step-invasion-requires neoplastic epithelial 1 Whitehead Institute for Biomedical Research cells to lose cell-cell adhesion and to gain motility, which 9 Cambridge Center enables them to invade the adjacent tissue. During the Cambridge, Massachusetts 02142 second step, intravasation, tumor cells penetrate 2 Cancer Genomics Program through the endothelium of blood or lymphatic vessels Broad Institute to enter the systemic circulation. Only some circulating Cambridge, Massachusetts 02141 tumor cells appear to be able to survive the passage 3 MGH Center for Cancer Research through circulation. Some of these survivors manage to Charlestown, Massachusetts 02129 complete the next step-extravasation-as they extrav-4 Ecole Normale Superieure asate through the capillary endothelium at distal sites. 75230 Paris Cedex 05 Finally, in the new host environment, an even smaller France subset of such metastasizing cells succeeds in prolifer-5 EMI 0229 INSERM ating from minute growths (micrometastases) into malig-CRLC Val d'Aurelle-Paul Lamarque nant, secondary tumors (Fidler, 2003). A central aim in 34298 Montpellier Cedex 5 the study of tumor metastasis is to understand the na-France ture of the distinct genetic and epigenetic changes that 6 Department of Molecular Genetics & Development program these individual steps. Ben Gurion University of the Negev Recently, our understanding of metastasis has been Beer Sheva 84105 expanded through microarray analyses of various hu-Israel man tumor samples. For example, several studies of 7 Department of Pathology human primary breast tumors have generated gene ex-Brigham and Women's Hospital pression profiles that are predictive of metastasis or Harvard Medical School poor survival rate (Ramaswamy et al., 2003; van't Veer et Boston, Massachusetts 02115 al., 2002). Such analyses are very powerful for producing fingerprints of metastatic tumor cells, which could be used as prognostic markers of metastatic diseases. However, due to the lack of further experimental manip-Summary ulation of human tumor samples, it has been very difficult to elucidate the specific contributions of such genes to Metastasis is a multistep process during which cancer tumor metastasis. cells disseminate from the site of primary tumors and Experimental animal models have been successfully establish secondary tumors in distant organs. In a used to identify molecular elements during metastasis. search for key regulators of metastasis in a murine For example, in an expression profile analysis comparbreast tumor model, we have found that the transcriping melanoma cells and their highly metastatic derivation factor Twist, a master regulator of embryonic mortives, RhoC was identified as essential for pulmonary phogenesis, plays an essential role in metastasis. Supmetastasis by melanoma cells that were injected intrapression of Twist expression in highly metastatic venously into mice (Clark et al., 2000). Recently, a set mammary carcinoma cells specifically inhibits their of genes, including osteopontin and IL-11, were shown ability to metastasize from the mammary gland to the to promote bone metastasis when human breast cancer lung. Ectopic expression of Twist results in loss of cells were injected via the intracardiac route (Kang et E-cadherin-mediated cell-cell adhesion, activation of al., 2003). Most of these models rely on the introduction mesenchymal markers, and induction of cell motility, of tumor cells directly into the systemic circulation. Such suggesting that Twist contributes to metastasis by approaches obviate the steps of invasion and intravasapromoting an epithelial-mesenchymal transition (EMT). tion and therefore are unlikely to reveal genes involved In human breast cancers, high level of Twist expresin these early steps of metastasis. sion is correlated with invasive lobular carcinoma, a Given the complexity of the process of metastasis, it highly infiltrating tumor type associated with loss of is essential to exploit experimental models in which each E-cadherin expression. These results establish a of the steps of metastasis is represented and can be mechanistic link between Twist, EMT, and tumor memanipulated individually. In this report, we exploit a tastasis. mouse mammary tumor model, in which a set of otherwise isogenic tumor cell populations is able to complete distinct steps of metastasis when implanted into the

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

• Loss of Prdm11 accelerates MYC-driven lymphomagenesis. • PRDM11 regulates transcription of targ... more • Loss of Prdm11 accelerates MYC-driven lymphomagenesis. • PRDM11 regulates transcription of target genes, including FOS and JUN. The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Em-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Research paper thumbnail of 284 Slug Controls P-cadherin and Regulates Stem/progenitor Cell Dynamics During Mammary Gland Morphogenesis

European Journal of Cancer, 2012

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are der... more The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Research paper thumbnail of Cox4i2, Ifit2, and Prdm11 Mutant Mice: Effective Selection of Genes Predisposing to an Altered Airway Inflammatory Response from a Large Compendium of Mutant Mouse Lines

PloS one, 2015

We established a selection strategy to identify new models for an altered airway inflammatory res... more We established a selection strategy to identify new models for an altered airway inflammatory response from a large compendium of mutant mouse lines that were systemically phenotyped in the German Mouse Clinic (GMC). As selection criteria we included published gene functional data, as well as immunological and transcriptome data from GMC phenotyping screens under standard conditions. Applying these criteria we identified a few from several hundred mutant mouse lines and further characterized the Cox4i2tm1Hutt, Ifit2tm1.1Ebsb, and Prdm11tm1.1ahl lines following ovalbumin (OVA) sensitization and repeated OVA airway challenge. Challenged Prdm11tm1.1ahl mice exhibited changes in B cell counts, CD4+ T cell counts, and in the number of neutrophils in bronchoalveolar lavages, whereas challenged Ifit2tm1.1Ebsb mice displayed alterations in plasma IgE, IgG1, IgG3, and IgM levels compared to the challenged wild type littermates. In contrast, challenged Cox4i2tm1Hutt mutant mice did not show a...

Research paper thumbnail of Twist, a master regulator of morphogenesis, plays an essential role in tumor metastasis

Cell, Jan 1, 2004

Metastasis is a multistep process during which cancer cells disseminate from the site of primary ... more Metastasis is a multistep process during which cancer cells disseminate from the site of primary tumors and establish secondary tumors in distant organs. In a search for key regulators of metastasis in a murine breast tumor model, we have found that the transcription factor Twist, a master regulator of embryonic morphogenesis, plays an essential role in metastasis. Suppression of Twist expression in highly metastatic mammary carcinoma cells specifically inhibits their ability to metastasize from the mammary gland to the lung. Ectopic expression of Twist results in loss of E-cadherin-mediated cell-cell adhesion, activation of mesenchymal markers, and induction of cell motility, suggesting that Twist contributes to metastasis by promoting an epithelial-mesenchymal transition (EMT). In human breast cancers, high level of Twist expression is correlated with invasive lobular carcinoma, a highly infiltrating tumor type associated with loss of E-cadherin expression. These results establish a mechanistic link between Twist, EMT, and tumor metastasis.

Research paper thumbnail of CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most ma... more The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2A HOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2A HOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4 + T-cells and CD8 + effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we

Research paper thumbnail of Senescence sensitivity of breast cancer cells is defined by positive feedback loop between CIP2A and E2F1

Cancer discovery, 2013

Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumo... more Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumor suppression. However, whether p53 inactivation actively suppresses senescence induction has been unclear. Here, we show that E2F1 overexpression, due to p53 or p21 inactivation, promotes expression of human oncoprotein CIP2A, which in turn, by inhibiting PP2A activity, increases stabilizing serine 364 phosphorylation of E2F1. Several lines of evidence show that increased activity of E2F1-CIP2A feedback renders breast cancer cells resistant to senescence induction. Importantly, mammary tumorigenesis is impaired in a CIP2A-deficient mouse model, and CIP2A-deficient tumors display markers of senescence induction. Moreover, high CIP2A expression predicts for poor prognosis in a subgroup of patients with breast cancer treated with senescence-inducing chemotherapy. Together, these results implicate the E2F1-CIP2A feedback loop as a key determinant of breast cancer cell sensitivity to senesce...

Research paper thumbnail of CIP2A Promotes Proliferation of Spermatogonial Progenitor Cells and Spermatogenesis in Mice

PLoS ONE, 2012

Protein phosphatase 2A (PP2A) is a critical regulator of protein serine/threonine phosphorylation... more Protein phosphatase 2A (PP2A) is a critical regulator of protein serine/threonine phosphorylation. However, the physiological and developmental roles of different PP2A complexes are very poorly understood. Here, we show that a newly characterized PP2A inhibitory protein CIP2A is co-expressed with ki-67 and with self-renewal protein PLZF in the spermatogonial progenitor cell (SPC) population in the testis. CIP2A and PLZF expression was shown also to correlate Ki-67 expression in human testicular spermatogonia. Functionally, CIP2A mutant mouse testes exhibited smaller number of PLZFpositive SPCs and reduced sperm counts. Moreover, seminiferous tubuli cells isolated from CIP2A mutant mice showed reduced expression of Plzf and other renewal genes Oct-4 and Nanog at mRNA level. However, PLZF-deficient testes did not show altered CIP2A expression. Importantly, spermatogonia-specific restoration of CIP2A expression rescued PLZF expression and sperm production defects observed in CIP2A mutant mice. Taken together, these results reveal first physiological function for an emerging human oncoprotein CIP2A, and provide insights into maintenance of PLZF-positive progenitors. Moreover, demonstration that CIP2A expression can be systematically inhibited without severe consequences to normal mouse development and viability may have clinical relevance regarding targeting of oncogenic CIP2A for future cancer therapies.

Research paper thumbnail of CIP2A Is Associated with Human Breast Cancer Aggressivity

Clinical Cancer Research, 2009

Purpose: To investigate the clinical relevance of the recently characterized human oncoprotein ca... more Purpose: To investigate the clinical relevance of the recently characterized human oncoprotein cancerous inhibitor of protein phosphatase 2A (CIP2A) in human breast cancer. Experimental Design: CIP2A expression (mRNA and protein) was measured in three different sets of human mammary tumors and compared with clinicopathologic variables. The functional role of CIP2A in breast cancer cells was evaluated by small interfering RNA-mediated depletion of the protein followed by an analysis of cell proliferation, migration, anchorage-independent growth, and xenograft growth. Results: CIP2A mRNA is overexpressed (n = 159) and correlates with higher Scarff-Bloom-Richardson grades (n = 251) in samples from two independent human breast cancer patients. CIP2A protein was found to be overexpressed in 39% of 33 human breast cancer samples. Furthermore, CIP2A mRNA expression positively correlated with lymph node positivity of the patients and with the expression of proliferation markers and p53 mutations in the tumor samples. Moreover, CIP2A protein expression was induced in breast cancer mouse models presenting mammary gland-specific depletion of p53 and either BRCA1 or BRCA2. Functionally, CIP2A depletion was shown to inhibit the expression of its target protein c-Myc. Loss of CIP2A also inhibited anchorageindependent growth in breast cancer cells. Finally, CIP2A was shown to support MDA-MB-231 xenograft growth in nude mice. Conclusions: Our data show that CIP2A is associated with clinical aggressivity in human breast cancer and promotes the malignant growth of breast cancer cells. Thus, these results validate the role of CIP2A as a clinically relevant human oncoprotein and warrant further investigation of CIP2A as a therapeutic target in breast cancer treatment. (Clin Cancer Res 2009;15(16):5092-100)

Research paper thumbnail of Snail and Slug Play Distinct Roles during Breast Carcinoma Progression

Clinical Cancer Research, 2006

Carcinoma progression is linked to a partially dedifferentiated epithelial cell phenotype. As pre... more Carcinoma progression is linked to a partially dedifferentiated epithelial cell phenotype. As previously suggested, this regulation could involve transcription factors, Snail and Slug, known to promote epithelial-mesenchymal transitions during development. Here, we investigate the role of Snail and Slug in human breast cancer progression. We analyzed Snail, Slug, and E-cadherin RNA expression levels and protein localization in large numbers of transformed cell lines and breast carcinomas, examined the correlation with tumor histologic features, and described, at the cellular level, Snail and Slug localization in carcinomas using combined in situ hybridization and immunolocalization. In contrast with transformed cell lines, Slug was found to colocalize with E-cadherin at the cellular level in normal mammary epithelial cells and all tested carcinomas. Snail also colocalized at the cellular level with E-cadherin in tumors expressing high levels of Snail RNA. In addition, Snail was significantly expressed in tumor stroma, varying with tumors. Slug and Snail genes were significantly overexpressed in tumors associated with lymph node metastasis. Finally, the presence of semidifferentiated tubules within ductal carcinomas was linked to Slug expression levels similar to or above normal breast samples. These results suggest that Snail or Slug expression in carcinoma cells does not generally preclude significant E-cadherin expression. They emphasize a link between Snail, Slug, and lymph node metastasis in a large sampling of mammary carcinomas, and suggest a role for Slug in the maintenance of semidifferentiated structures. Snail and Slug proteins seem to support distinct tumor invasion modes and could provide new therapeutic targets.

Research paper thumbnail of Loss of PRDM11 promotes MYC-driven lymphomagenesis

Blood, 2014

The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are der... more The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.