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See detailThe proteolytic activity of MT4-MMP is required for its proangiogenic and pro-metastatic promoting effects
Host, Lorin; Paye, Alexandra ULg; Detry, Benoît ULg et al

in International Journal of Cancer = Journal International du Cancer (2012), 131(7), 1537-1548

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a ... [more ▼]

MT4-MMP expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However whether these pro-tumorigenic and pro-metastatic effects of MT4-MMP are related to a proteolytic action is not known yet. Through site directed mutagenesis MT4-MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4-MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in RAG -/- mice. All these effects were abrogated upon MT4-MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor-derived MT4-MMP, but not host-derived MT4-MMP contributes to angiogenesis. A genetic approach using MT4-MMP-deficient mice revealed that the status of MT4-MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4-MMP requires a permissive microenvironment. Indeed, tumor-derived MT4-MMP failed to circumvent the lack of an host angio-promoting factor such as lasminogen activator inhibitor (PAI-1). Overall, our study demonstrates the key contribution of MT4-MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4-MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination [less ▲]

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See detailHTLV-1 positive and negative T cells cloned from infected individuals display telomerase and telomere genes deregulation that predominate in activated but untransformed CD4+ T cells.
Zane, Linda; Sibon, David; CAPRARO, Valérie ULg et al

in International Journal of Cancer = Journal International du Cancer (2012), 131(4), 821-33

Untransformed HTLV-1 positive CD4(+) cells from infected individuals are selected for expressing tax and displaying morphological features consistent with telomere dysfunctions. We show that in resting ... [more ▼]

Untransformed HTLV-1 positive CD4(+) cells from infected individuals are selected for expressing tax and displaying morphological features consistent with telomere dysfunctions. We show that in resting HTLV-1 positive CD4(+) cells cloned from patients, hTERT expression parallels tax expression and cell cycling. Upon activation, these cells dramatically augment tax expression, whereas their increase in telomerase activity is about 20 times lower than that of their uninfected counterpart. Activated HTLV-1 positive CD4(+) but not uninfected CD4(+) or CD8(+) clones also repress the transcription of TRF1, TPP1, TANK1, POT1, DNA-PKc and Ku80. Both infected and uninfected lymphocytes from infected individuals shared common telomere gene deregulations toward a pattern consistent with premature senescence. ATLL cells displayed the highest telomerase activity (TA) whereas recovered a telomere gene transcriptome close to that of normal CD4(+) cells. In conclusion HTLV-1-dependent telomere modulations seem involved in clonal expansion, immunosuppression, tumor initiation and progression. [less ▲]

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See detailUnimpeded skin carcinogenesis in K14-HPV16 transgenic mice deficient for plasminogen activator inhibitor
Masset, Anne; Maillard, Catherine ULg; Sounni, Nor Eddine ULg et al

in International Journal of Cancer = Journal International du Cancer (2011), 128(2), 283-93

Angiogenesis, extracellular matrix remodeling and cell migration are associated with cancer progression and involve at least, the plasminogen activating system and its main physiological inhibitor, the ... [more ▼]

Angiogenesis, extracellular matrix remodeling and cell migration are associated with cancer progression and involve at least, the plasminogen activating system and its main physiological inhibitor, the plasminogen activator inhibitor-1 (PAI-1). Considering the recognized importance of PAI-1 in the regulation of tumor angiogenesis and invasion in murine models of skin tumor transplantation, we explored the functional significance of PAI-1 during early stages of neoplastic progression in the transgenic mouse model of multistage epithelial carcinogenesis (K14-HPV16 mice). We have studied the effect of genetic deletion of PAI-1 on inflammation, angiogenesis, lymphangiogenesis, as well as tumor progression. In this model, PAI-1 deficiency neither impaired keratinocyte hyperproliferation or tumor development, nor affected the infiltration of inflammatory cells and development of angiogenic or lymphangiogenic vasculature. We are reporting evidence for concomitant lymphangiogenic and angiogenic switches independent to PAI-1 status. Taken together, these data indicate that PAI-1 is not rate limiting for neoplastic progression and vascularization during premalignant progression, or that there is a functional redundancy between PAI-1 and other tumor regulators, masking the effect of PAI-1 deficiency in this long-term model of multi-stage epithelial carcinogenesis. [less ▲]

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See detailHuman glioblastoma-initiating cells invade specifically the subventricular zones and olfactory bulbs of mice after striatal injection.
Kroonen, Jérôme ULg; Nassen, Jessica ULg; Boulanger, Yves-Gauthier et al

in International Journal of Cancer = Journal International du Cancer (2011), 129(3), 574-585

This study reports the subsequent isolation of human glioblatoma cells able to initiate experimental brain tumors, specifically and repeatedly found in the subventricular zones and olfactory bulbs ... [more ▼]

This study reports the subsequent isolation of human glioblatoma cells able to initiate experimental brain tumors, specifically and repeatedly found in the subventricular zones and olfactory bulbs following xenograft in the caudate putamen of immunodeficient mice.In patients with glioblastoma multiforme, recurrence is the rule despite continuous advances in surgery, radiotherapy and chemotherapy. Within these malignant gliomas, glioblastoma stem cells or initiating cells have been recently described and they were shown to be specifically involved in experimental tumorigenesis. In this study, we show that some human glioblastoma cells injected into the striatum of immunodeficient nude mice exhibit a tropism for the subventricular zones. There and similarily to neurogenic stem cells, these subventricular glioblastoma cells were then able to migrate towards the olfactory bulbs. Finally, the glioblastoma cells isolated from the adult mouse subventricular zones and olfactory bulbs display high tumorigenicity when secondary injected in a new mouse brain. Together, these data suggest that neurogenic zones could be a reservoir for particular cancer-initiating cells. [less ▲]

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See detailTIMP-2 binding with cellular MT1-MMP stimulates invasion-promoting MEK/ERK signaling in cancer cells
Sounni, Nor Eddine ULg; Rozanov, D. V.; Remacle, A. G. et al

in International Journal of Cancer = Journal International du Cancer (2010), 126(5), 1067-78

Both invasion-promoting MT1-MMP and its physiological inhibitorTIMP-2 play a significant role in tumorigenesis and are identified in the most aggressive cancers. Despite its antiproteolytic effects in ... [more ▼]

Both invasion-promoting MT1-MMP and its physiological inhibitorTIMP-2 play a significant role in tumorigenesis and are identified in the most aggressive cancers. Despite its antiproteolytic effects in vitro, clinical data suggest that TIMP-2 expression is positively associated with tumor recurrence, thus emphasizing the wide-ranging role of TIMP-2 in malignancies. To shed light on this role of TIMP-2, we report that low concentrations of TIMP-2, by interacting with MT1-MMP (a specific membrane receptor of TIMP-2), induce the MEK/ERK signaling cascade in fibrosarcoma HT1080 cells which express MT1-MMP naturally. TIMP-2 binding with cell surface-associated MT1-MMP stimulates phosphorylation of MEK1/2, which is upstream of ERK1/2, and the ERK1/2 substrate p90RSK. Consistent with volumes of literature, we confirmed that the activation of ERK stimulated cell migration. Both the transcriptional silencing of MT1-MMP and the inhibition of MEK1/2 reversed the signaling effects of TIMP-2/MT1-MMP while the active site-targeting MMP inhibitor GM6001 did not. Our data suggest that both the interactions of TIMP-2 with MT1-MMP, which activate the pro-migratory ERK signaling cascade, and the conventional inhibition of MT1-MMP's catalytic activity by TIMP-2, play a role in the invasion-promoting function of MT1-MMP. The TIMP-2-induced stimulation of ERK signaling in cancer cells explains the direct, as opposed to the inverse, association of TIMP-2 expression with poor prognosis in cancer. [less ▲]

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See detailVersican overexpression in human breast cancer lesions: Known and new isoforms for stromal tumor targeting.
Kischel, Philippe ULg; Waltregny, David ULg; Dumont, Bruno ULg et al

in International Journal of Cancer = Journal International du Cancer (2010), 126(3), 640-50

Proteoglycans play a key role in cancer development and progression by participating in the constitution of a specific fertile tumor microenvironment. As they are largely overexpressed in the malignant ... [more ▼]

Proteoglycans play a key role in cancer development and progression by participating in the constitution of a specific fertile tumor microenvironment. As they are largely overexpressed in the malignant stroma, proteoglycans provide a reservoir of potential new targets for anticancer therapies, because they can serve to convey toxic payloads in the close proximity of cancer cells and subsequently destroy them. In this context, versican, a proteoglycan largely overexpressed in several solid cancers, bears the potential to be such an ideal target. As 4 main versican isoforms have been characterized, we sought to determine which isoform could represent the best target in human breast cancer. We used a series of 10 primary breast cancer lesions that were characterized as overexpressing the versican protein, when compared with matched normal breast tissues, using shotgun mass spectrometry and immunohistochemistry experiments. Quantitative polymerase chain reaction and western-blotting experiments were used to evaluate versican isoform expression in breast cancer/normal tissue pairs for which ARN quality was excellent. All known isoforms were significantly overexpressed in the malignant lesions, both at the mRNA and at the protein levels. In the course of this study, we also identified and cloned a new alternatively spliced versican isoform, referred to as V4, which was also found to be upregulated in human breast cancer. This study provides for the first time a comprehensive mRNA and protein analysis of versican isoforms expression in human breast tissues, and offers insights into which therapeutic strategy would be best suited to target versican in human breast cancer lesions. [less ▲]

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See detailSelective osteopontin knockdown exerts anti-tumoral activity in a human glioblastoma model.
Lamour, Virginie ULg; Le Mercier, M.; Lefranc, F. et al

in International Journal of Cancer = Journal International du Cancer (2010), 126

Osteopontin (OPN), a member of the SIBLING (Small Integrin-Binding LIgand N-linked Glycoprotein) family, is overexpressed in human glioblastoma. Higher levels of OPN expression correlate with increased ... [more ▼]

Osteopontin (OPN), a member of the SIBLING (Small Integrin-Binding LIgand N-linked Glycoprotein) family, is overexpressed in human glioblastoma. Higher levels of OPN expression correlate with increased tumor grade and enhanced migratory capacity of tumor cells. Based on these observations, we explored the possibility that knocking down OPN expression in glioblastoma cells could exert an anti-tumoral activity using an avian in vivo glioblastoma model that mimics closely human gliobastoma. Human U87-MG glioma cells transfected with specific anti-OPN small interfering RNAs (siRNAs) were grafted onto the chicken chorio-allantoic membrane (CAM). OPN-deficient U87-MG cells gave rise to tumors that were significantly smaller than tumors formed from untransfected cells (paired t-test, p<0.05). Accordingly, the amount of proliferating cells in OPN-deficient tumors showed a six-fold reduction when compared to control tumors. However, OPN inhibition did not affect significantly tumor-associated angiogenesis. In vitro, OPN-silenced U87-MG and U373-MG cells showed decreased motility and migration. This is the first demonstration that OPN inhibition blocks glioma tumor growth, making this invasion-related protein an attractive target for glioma therapy. (c) 2009 UICC. [less ▲]

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See detailTumor ZAC1 expression is associated with the response to somatostatin analog therapy in patients with acromegaly.
Theodoropoulou, Marily; Tichomirowa, Maria A; Sievers, Caroline et al

in International Journal of Cancer = Journal International du Cancer (2009), 125(9), 2122-6

Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and ... [more ▼]

Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and acromegaly-associated growth hormone secreting pituitary tumors. Although a good portion of acromegalic patients gets normalized after SSA treatment, strict hormonal control is not achieved in a sizeable proportion of these patients. The reasons for this incomplete response to SSA treatment are unclear. We have found that the tumor suppressor ZAC1 (LOT1/PLAGL1) is essential for the antiproliferative effect of SSA in pituitary tumor cells. The aim of the present retrospective cohort study was to determine whether ZAC1 immunoreactivity in archival somatotrophinoma tissue derived from 45 patients with acromegaly routinely pretreated with SSA before surgery, was associated with response to SSA (normalization of GH, IGF-I and presence of tumor shrinkage). All tumors displayed ZAC1 immunoreactivity [weak (+; n = 15), moderate (++; n = 16) and strong (+++; n = 14)]. A significant positive correlation was found between strong ZAC1 immunoreactivity and IGF-I normalization and presence of tumor shrinkage after SSA treatment, which was not affected by age at diagnosis, gender or duration of SSA treatment. These in vivo data combined with the antiproliferative properties of ZAC1/Zac1 provide evidence of a mechanistic role for this transcription factor on SSA induced tumor shrinkage and hormone normalization. [less ▲]

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See detailHyperforin and aristoforin inhibit lymphatic endothelial cell proliferation in vitro and suppress tumor-induced lymphangiogenesis in vivo
Rothley, M.; Schmid, A.; Thiele, W. et al

in International Journal of Cancer = Journal International du Cancer (2009), 125(1), 34-42

The phloroglucinol derivative hyperforin, a major bioactive constituent of St. John's wort, is increasingly recognized as being able to regulate a variety of pathobiological processes and, thus, to ... [more ▼]

The phloroglucinol derivative hyperforin, a major bioactive constituent of St. John's wort, is increasingly recognized as being able to regulate a variety of pathobiological processes and, thus, to possess potential therapeutic properties. In the context of cancer, hyperforin induces the apoptosis of cancer cells, inhibits angiogenesis and suppresses metastasis formation. Here, we report a new pharmacological function of hyperforin and its stabilized derivative aristoforin, namely the suppression of lymphatic endothelial cell (LEC) growth and lymphangiogenesis. At concentrations less than 10 M, we found that these compounds induce cell cycle arrest of LECs, and at higher concentrations induce apoptosis. The loss of mitochondrial membrane potential and the activation of caspase-9 during the induction of apoptosis indicate that the intrinsic pathway of apoptosis is stimulated by these compounds, similar to the situation in tumor cells. In thoracic duct ring outgrowth assays, hyperforin and aristoforin both inhibited lymphangiogenesis, as evidenced by the suppression of lymphatic capillary outgrowth. In an in vivo animal model, both compounds were able to inhibit tumor-induced lymphangiogenesis. Together these data substantiate a new role for hyperforin and its derivatives as suppressors of lymphangiogenesis, and support their further investigation as potential anticancer drugs that target tumor growth and metastasis at multiple levels. [less ▲]

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See detailExperimental anti-angiogenesis causes upregulation of genes associated with poor survival in glioblastoma.
Saidi, Ahlame; Javerzat, Sophie; Bellahcene, Akeila ULg et al

in International Journal of Cancer = Journal International du Cancer (2008), 122(10), 2187-98

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with ... [more ▼]

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with classic chemotherapy. Exploring gene regulation in tumor cells during anti-angiogenesis might help to comprehend the molecular basis of response to treatment. To generate a defined anti-angiogenic condition in vivo, we transfected human glioma cells with short-interfering RNAs against VEGF-A and implanted them on the chick chorio-allantoic membrane. Gene regulation in avascular tumors was studied using human Affymetrixtrade mark GeneChips. Potentially important genes were further studied in glioma patients. Despite strong VEGF inhibition, we observed recurrent formation of small, avascular tumors. CHI3L2, IL1B, PI3/elafin and CHI3L1, which encodes for YKL-40, a putative prognosticator for various diseases, including cancer, were strongly up-regulated in avascular glioma. In glioblastoma patients, these genes showed coregulation and their expression differed significantly from low-grade glioma. Importantly, high levels of CHI3L1 (p = 0.036) and PI3/elafin mRNA (p = 0.0004) were significantly correlated with poor survival. Cox regression analysis further confirmed that PI3 and CHI3L1 levels are survival markers independent from patient age and sex. Elafin-positive tumor cells were only found in glioblastoma, where they were clustered around necrotic areas. PI3/elafin is strongly induced by serum deprivation and hypoxia in U87 glioma cells in vitro. Our results indicate that anti-angiogenesis in experimental glioma drives expression of critical genes which relate to disease aggressiveness in glioblastoma patients. In particular, CHI3L1 and PI3/elafin may be useful as new prognostic markers and new therapeutic targets. [less ▲]

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See detailIdentification of new accessible tumor antigens in human colon cancer by ex vivo protein biotinylation and comparative mass spectrometry analysis.
Conrotto, Paolo; Roesli, Cristof; Rybak, Jascha et al

in International Journal of Cancer = Journal International du Cancer (2008), 123(12), 2856-2864

One of the most promising new strategies for the development of efficacious cancer therapies relies on the targeted delivery of biopharmaceutical to the tumor environment by the use of selective and ... [more ▼]

One of the most promising new strategies for the development of efficacious cancer therapies relies on the targeted delivery of biopharmaceutical to the tumor environment by the use of selective and specific antibodies. The identification of accessible perivascular proteins selectively overexpressed in cancer tissue may facilitate the development of antibody-based biopharmaceutical administration. This approach is potentially highly selective and specific, combining the presence of tumor biomarkers readily accessible from the blood vessels and the high rate of angiogenesis characteristic of cancer tissues. We performed ex vivo perfusions of surgically resected human colon cancer using a reactive ester derivative of biotin, thus achieving a selective covalent modification of accessible proteins in vascular structures and stroma. After extraction and purification, biotinylated proteins were digested and the resulting peptides submitted to a comparative mass spectrometry-based proteomic analysis, revealing quantitative differences between normal and cancer colon. Sixty-seven of the total 367 proteins identified were found to be preferentially expressed at the tumor site. We generated human monoclonal antibodies against 2 potential tumor targets, NGAL and GW112, and we proved their selective expression in cancer colon and not or barely in healthy tissues. This article presents the first proteomic analysis of human colorectal cancer structures readily accessible from the tumor vasculature, revealing the overexpression of novel tumor antigens which may serve as selective targets for antibody-based imaging and therapeutic biomolecular strategies. (c) 2008 Wiley-Liss, Inc. [less ▲]

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See detailToll-like receptor-4 is expressed in meningiomas and mediates the antiproliferative action of paclitaxel.
Tichomirowa, Maria A.; Theodoropoulou, Marily; Daly, Adrian ULg et al

in International Journal of Cancer = Journal International du Cancer (2008), 123(8), 1956-63

Meningiomas are the second most common type of brain and CNS tumors by histology. Surgery and radiotherapy are main treatment options, but meningiomas may be impossible to adequately resect or may regrow ... [more ▼]

Meningiomas are the second most common type of brain and CNS tumors by histology. Surgery and radiotherapy are main treatment options, but meningiomas may be impossible to adequately resect or may regrow after surgery. In spite of many experimental attempts, there is no generally accepted chemotherapeutic approach. We have studied in a series of meningiomas the expression of the Toll-like receptor 4 (TLR4), which apart from its major role as a key factor of the innate immune system, is believed to play a role in tumorigenesis. All meningiomas studied expressed TLR4 mRNA and protein at variable degree. Paclitaxel, a ligand of TLR4, exhibited a dose- and time-dependent growth suppression in both monolayer and spheroid meningioma cell cultures. The knockdown of TLR4 with siRNA in meningioma cell cultures abrogated the inhibitory effect of paclitaxel. The suppressive action of paclitaxel on meningioma cell growth was enhanced in the presence of fluvastatin or the mitogen-actvated protein kinase (ERK1/2) inhibitor PD98059. At least part of the growth suppressive effect was mediated by the induction of apoptosis in meningioma cells by paclitaxel alone or in combination with fluvastatin. In conclusion, our in vitro results suggest that paclitaxel alone or in combination with other inhibitors of cell growth (statins, MAPK inhibitors) could provide a potential tool for the treatment of TLR4 expressing meningiomas. [less ▲]

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See detailHedgehog signaling pathway is inactive in colorectal cancer cell lines
Chatel, Guillaume; Ganeff, Corinne ULg; Boussif, Naima et al

in International Journal of Cancer = Journal International du Cancer (2007), 121(12), 2622-2627

The Hedgehog (Hh) signaling pathway plays an important role in human development. Abnormal activation of this pathway has been observed in several types of human cancers, such as the upper gastro ... [more ▼]

The Hedgehog (Hh) signaling pathway plays an important role in human development. Abnormal activation of this pathway has been observed in several types of human cancers, such as the upper gastro-intestinal tract cancers. However, activation of the Hh pathway in colorectal cancers is controversial. We analyzed the expression of the main key members of the Hh pathway in 7 colon cancer cell lines in order to discover whether the pathway is constitutively active in these cells. We estimated the expression of SHH, IHH, PTCH, SMO, GLI1, GLI2, GLI3, SUFU and HHIP genes by RT-PCR. Moreover, Hh ligand, Gli3 and Sufu protein levels were quantified by western blotting. None of the cell lines expressed the complete set of Hh pathway members. The ligands were absent from Colo320 and HCT116 cells, Smo from Colo205, HT29 and WiDr. GLI1 gene was not expressed in SW480 cells nor were GLI2/GLI3 in Colo205 or Caco-2 cells. Furthermore the repressive form of Gli3, characteristic of an inactive pathway, was detected in SW480 and Colo320 cells. Finally treatment of colon cancer cells with cyclopamine, a specific inhibitor of the Hh pathway, did not downregulate PTCH and GLI1 genes expression in the colorectal cells, whereas it did so in PANC1 control cells. Taken together, these results indicate that the aberrant activation of the Hh signaling pathway is not common in colorectal cancer cell lines. (c) 2007 Wiley-Liss, Inc. [less ▲]

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See detailPresence of simian virus 40 DNA sequences in diffuse large B-cell lymphomas in Tunisia correlates with aberrant promoter hypermethylation of multiple tumor suppressor genes
Amara, Khaled; Trimeche, Mounir; Ziadi, Sonia et al

in International Journal of Cancer = Journal International du Cancer (2007), 121(12), 2693-2702

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See detailGs alpha overexpression and loss of Gs alpha imprinting in human somatotroph adenomas: association with tumor size and response to pharmacologic treatment.
Picard, Christophe; Silvy, Monique; Gerard, c et al

in International Journal of Cancer = Journal International du Cancer (2007), 121(6), 1245-1252

Gs alpha, the alpha-subunit of the heterotrimeric GTP-binding protein, is coded from the GNAS gene, which is imprinted in a tissue-specific manner. Gs alpha is paternally silenced in normal pituitary, but ... [more ▼]

Gs alpha, the alpha-subunit of the heterotrimeric GTP-binding protein, is coded from the GNAS gene, which is imprinted in a tissue-specific manner. Gs alpha is paternally silenced in normal pituitary, but Gs alpha imprinting relaxation is found in some tumoral tissue. In addition, Gs alpha mRNA levels are high in some somatotroph adenomas not bearing the active Gs alpha mutant, the gsp oncogene. In this study, the impact of loss of imprinting on Gs alpha expression level and on tumoral phenotype has been investigated. We compared the expression and imprinting of 4 transcripts of GNAS locus (NESP55, XL alpha s, exon 1A, Gs alpha) of 60 somatotroph adenomas with those of 23 lactotroph adenomas. The paternal and maternal transcripts were quantified using allele-specific real-time PCR and FokI polymorphism. Moreover, the methylation of exon 1A DMR was analyzed. As is the case for the gsp oncogene, high Gs alpha expression in gsp- tumors was associated with smaller tumor size and better octreotide sensitivity. A strong imprinting relaxation (percentage of paternal Gs alpha expression >or=7.5%) was found only in gsp- tumors. The loss of Gs alpha imprinting was associated with a decrease in exon 1A mRNA expression. Unexpectedly, the methylation status of exon 1A DMR was not modified in relaxed tumors. Maternal Gs alpha mRNA level decreased with exon 1A level, and consequently the loss of Gs alpha imprinting did not induce the expected Gs alpha overexpression. Finally, XL alpha s mRNA level correlated with that of paternal Gs alpha and of NESP55 showing the complexity of gene regulation in the GNAS locus. [less ▲]

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See detailExpression of dentin sialophosphoprotein in human prostate cancer and its correlation with tumor aggressiveness
Chaplet, Michael; Waltregny, David ULg; Detry, Cédric ULg et al

in International Journal of Cancer = Journal International du Cancer (2006), 118(4), 850-856

Recent studies have demonstrated that two SIBLING family members, bone sialoprotein (BSP) and osteopontin (OPN), are overexpressed in human prostate cancer. The expression of these proteins is associated ... [more ▼]

Recent studies have demonstrated that two SIBLING family members, bone sialoprotein (BSP) and osteopontin (OPN), are overexpressed in human prostate cancer. The expression of these proteins is associated with the acquisition of a metastatic phenotype by cancer cells and a poor prognosis for the patient. Dentin sialophosphoprotein (DSPP) shares several structural and genetic features with OPN and BSP. The presence of DSPP has been recently established in salivary glands, indicating that its expression is not restricted to mineralized tissues. However, its potential expression in human tumors has not been addressed yet. In this study, we sought to evaluate the expression of DSPP in human prostate cancer. Immunohistochemistry was performed on 69 prostate cancer specimens using LFMb-21 anti-DSPP monoclonal antibody. All of the prostate cancer lesions examined expressed detectable levels of DSPP, as compared with no or low level of expression in adjacent normal glands (p < 0.0001). High grade prostatic intraepithelial neoplasia (HGPIN) glands generally displayed DSPP expression levels that were similar to those found in neighboring cancer glands. DSPP expression was significantly associated with the pathological stage (p = 0.0087) and the Gleason score (p = 0.0176) of the tumors. Western Blot was performed on 5 representative prostate tumor extracts and 3 prostatic tumor cell lines (PC3, LNCaP and DU145). All tumor extracts and cell lines analyzed have been found to express DSPP. In addition, in situ hybridization was used to assess the presence of DSPP mRNA. DSPP was detected at the RNA level in both HGPIN and tumoral glands. This study shows for the first time that DSPP is ectopically expressed in human prostate cancer. The expression of this SIBLING protein strongly correlates with conventional histopathological prognostic indicators of prostate cancer progression. (c) 2005 Wiley-Liss, Inc. [less ▲]

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See detailTransactivation of MCP-1/CCL2 by beta-catenin/TCF-4 in human breast cancer cells
Mestdagt, Mélanie ULg; Polette, M.; Buttice, G. et al

in International Journal of Cancer = Journal International du Cancer (2006), 118(1), 35-42

The loss of E-cadherin expression and the translocation of beta-catenin to the nucleus are frequently associated with the metastatic conversion of epithelial cells. In the nucleus, beta-catenin binds to ... [more ▼]

The loss of E-cadherin expression and the translocation of beta-catenin to the nucleus are frequently associated with the metastatic conversion of epithelial cells. In the nucleus, beta-catenin binds to the TCF/LEF-1 (T-cell factor/ lymphoid enhancer factor) transcription factor family resulting in the activation of several genes, some of them having important implications in tumour progression. In our study, we investigated the potential regulation of monocyte chemotactic protein-1 (MCP-1/CCL2) expression by the beta-catenin/TCF pathway. This CC-chemokine has been implicated in tumour progression events such as angiogenesis or tumour associated macrophage (TAM) infiltration. We thus demonstrated that MCP-1 expression correlates with the reorganization of the E-cadherin/beta-catenin complexes. Indeed, MCP-1 was expressed by invasive breast cancer cells (MDA-MB-231, BT549 and Hs578T), which do not express E-cadherin but was not produced by noninvasive breast cancer cell lines (MCF7 and T47D) expressing high level of E-cadherin. In addition, the MCP-1 promoter was activated in BT549 breast cancer cells transfected with beta-catenin and TCF-4 cDNAs. The MCP-1 mRNA level was similarly upregulated. Moreover, we showed that MCP-1 mRNA was downregulated after transfection with a siRNA against beta-catenin in both BT549 and Hs578T cells. Our results therefore identify MCP-1 as a target of the beta-catenin/TCF/LEF pathway in breast tumour cells, a regulation which could play a key role in breast tumour progression. (c) 2005 Wiley-Liss, Inc. [less ▲]

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See detailMigration-stimulating factor displays HEXXH-dependent catalytic activity important for promoting tumor cell migration
Houard, X.; Germain, S.; Gervais, M. et al

in International Journal of Cancer = Journal International du Cancer (2005), 116(3), 378-384

Like most extracellular matrix (ECM) components, fibronectin (Fn) is proteolyzed generating specific activities. Fibronectin proteinase (Fn-proteinase) represents such a cryptic activity located in the ... [more ▼]

Like most extracellular matrix (ECM) components, fibronectin (Fn) is proteolyzed generating specific activities. Fibronectin proteinase (Fn-proteinase) represents such a cryptic activity located in the gelatin-binding domain (GBD) of Fn and displays a zinc metalloproteinase activity. The migration-stimulating factor (MSF) is a truncated Fn isoform generated by alternative mRNA splicing and corresponds to the N-terminal part of Fn that comprises the GBD. We show that several human mammary epithelial cells express MSF and constitutively produce Fn-proteinase activity. Furthermore, recombinant M F produced by HEK-293 and MCF-7 cells possesses a constitutive Fn-proteinase activity. Mutating the putative zinc-binding motif, HEXXH, of the protein abolishes its activity thereby demonstrating its specificity. Using PCR, we showed that MSF is barely expressed in normal breast tissues, whereas its expression is significantly increased in tumors. Furthermore, an association between MSF expression and invasive capacity is observed in various breast adenocarcinoma cell lines. Indeed, when stably transfected in non-invasive MCF-7 cells, MSF promotes cell migration in a mechanism mostly dependent on its Fn-proteinase activity. In summary, our study shows that: (i) MSF displays constitutive Fn-proteinase activity; (ii) MSF expression is induced in human breast cancer; and (iff) MSF confers pro-migratory activity that depends mostly on its Fn-proteinase activity. These results suggest that MSF may be involved in tumor progression. (C) 2005 Wiley-Liss, Inc. [less ▲]

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See detailRole for casein kinase 2 in the regulation of HIF-1 activity.
Mottet, Denis ULg; Ruys, Sebastien Pyr Dit; Demazy, Catherine et al

in International Journal of Cancer = Journal International du Cancer (2005), 117(5), 764-74

Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription factor that plays a major role in cellular adaptation to hypoxia. The mechanisms regulating HIF-1 activity occurs at multiple levels in ... [more ▼]

Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription factor that plays a major role in cellular adaptation to hypoxia. The mechanisms regulating HIF-1 activity occurs at multiple levels in vivo. The HIF-1alpha subunit is highly sensible to oxygen and is rapidly degraded by the proteasome 26S in normoxia. Activation in hypoxia occurs through a multistep process including inhibition of HIF-1alpha degradation, but also increase in the transactivation activity of HIF-1. Several data indicate that phosphorylation could play a role in this regulation. In this report, we investigated the role of casein kinase 2 (CK2), an ubiquitous serine/threonine kinase, in the regulation of HIF-1 activity. Hypoxia was capable of increasing the expression of the beta subunit of CK2, of inducing a relocalization of this subunit at the plasma membrane, of inducing nuclear translocation of the alpha subunit and of increasing CK2 activity. Three inhibitors of this kinase, DRB (5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole), TBB (4,5,6,7-tetrabromotriazole) and apigenin, as well as overexpression of a partial dominant negative mutant of CK2alpha, were shown to inhibit HIF-1 activity as measured by a reporter assay and through hypoxia-induced VEGF and aldolase expression. This does not occur at the stabilization process since they did not affect HIF-1alpha protein level. DNA-binding activity was also not inhibited. We conclude that CK2 is an important regulator of HIF-1 transcriptional activity but the mechanism of this regulation remains to be determined. Since HIF-1 plays a major role in tumor angiogenesis and since CK2 has been described to be overexpressed in tumor cells, this new pathway of regulation can be one more way for tumor cells to survive. [less ▲]

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See detailUpregulation of MMPs by soluble E-cadherin in human lung tumor cells
Nawrocki-Raby, B.; Gilles, Christine ULg; Polette, M. et al

in International Journal of Cancer = Journal International du Cancer (2003), 105(6), 790-795

Loss of E-cadherin/catenin mediated cell-cell adhesion and overexpression of matrix metalloproteinases (MMPs) are largely involved in tumor invasion. It has been recently shown that high levels of a ... [more ▼]

Loss of E-cadherin/catenin mediated cell-cell adhesion and overexpression of matrix metalloproteinases (MMPs) are largely involved in tumor invasion. It has been recently shown that high levels of a soluble 80 kDa fragment of E-cadherin, resulting from a cleavage by IVIMPs, are found in serum and in urine from cancer patients. Additionally, this soluble E-cadherin (sE-CAD) promotes cell invasion into chick heart and into collagen type I gels. The aim of our study was to examine the mechanism of sE-CAD-induced cell invasion. Since MMPs play a crucial role in invasion, we looked for induction of MMPs by sE-CAD in noninvasive human lung tumor cells 16HBE. An induction of MMP-2, MMP-9 and MTI-MMP expression was observed both at the mRNA and at the protein level in the presence of sE-CAD (in conditioned medium form or in E-cadherin HAV peptide form). No induction of MMP-I, -3 and -7 or variation of the levels of their inhibitors, TIMP-I and TIMP-2, were detected. The biologic relevance of the sE-CAD-induced MMP upregulation was tested by demonstrating that sE-CAD promotes in vitro cell invasion in a modified Boyden chamber assay. These data provide new insight into mechanisms of tumor invasion by ectodomain shedding of the cell-cell adhesion molecule E-cadherin. (C) 2003 Wiley-Liss, Inc. [less ▲]

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