References of "Willems, Luc"
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See detailVaccination against delta-Retroviruses: The Bovine Leukemia Virus Paradigm.
Gutierrez, Geronimo; Rodriguez, Sabrina M.; De Brogniez, Alix ULg et al

in Viruses (2014), 6(6), 2416-2427

Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related d-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly ... [more ▼]

Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related d-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia virus is a major pathogen of cattle, causing important economic losses due to a reduction in production, export limitations and lymphoma-associated death. In the absence of satisfactory treatment for these diseases and besides the prevention of transmission, the best option to reduce the prevalence of d-retroviruses is vaccination. Here, we provide an overview of the different vaccination strategies in the BLV model and outline key parameters required for vaccine efficacy. [less ▲]

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See detailRole of MCM proteins in HTLV-1 transcription
Barez, Pierre-Yves ULg; Carpentier, Alexandre ULg; Boxus, Mathieu et al

Conference (2013, December 13)

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See detailMassive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites During Primary Infection
Gillet, Nicolas ULg; Gutiérrez, Gerónimo; Rodriguez, Sabrina ULg et al

in PLoS Pathogens (2013), 9(10),

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These ... [more ▼]

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed regions. [less ▲]

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See detailThe role of epigenetics in malignant pleural mesothelioma
Vandermeers, Fabian; Neelature Sriramareddy, Sathya; Chrisostome, Costa et al

in Lung Cancer (2013), 81

Malignant pleural mesothelioma (MPM) is an almost invariably fatal cancer of the pleura due to asbestos exposure. Increasing evidence indicates that unresponsiveness to chemotherapy is due to epigenetic ... [more ▼]

Malignant pleural mesothelioma (MPM) is an almost invariably fatal cancer of the pleura due to asbestos exposure. Increasing evidence indicates that unresponsiveness to chemotherapy is due to epigenetic errors leading to inadequate gene expression in tumor cells. The availability of compounds that modulate epigenetic modifications, such as histone acetylation or DNA methylation, offers new prospects for treatment of MPM. Here, we review latest findings on epigenetics in mesothelioma and present novel strategies for promising epigenetic thérapies. [less ▲]

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See detailAcetylation at lysine 346 controls the transforming activity of the HTLV-1 Tax oncoprotein in the Rat-1 fibroblast model
Lodewick, Julie; Sampaio, Carla; Boxus, Mathieu et al

in Retrovirology (2013), 2013(10), 75

Background Transformation by the Tax oncoprotein of the human T cell leukemia virus type 1 (HTLV-1) is governed by actions on cellular regulatory signals, including modulation of specific cellular gene ... [more ▼]

Background Transformation by the Tax oncoprotein of the human T cell leukemia virus type 1 (HTLV-1) is governed by actions on cellular regulatory signals, including modulation of specific cellular gene expression via activation of signaling pathways, acceleration of cell cycle progression via stimulation of cyclin-dependent kinase activity leading to retinoblastoma protein (pRb) hyperphosphorylation and perturbation of survival signals. These actions control early steps in T cell transformation and development of Adult T cell leukemia (ATL), an aggressive malignancy of HTLV-1 infected T lymphocytes. Post-translational modifications of Tax by phosphorylation, ubiquitination, sumoylation and acetylation have been implicated in Tax-mediated activation of the NF-B pathway, a key function associated with Tax transforming potential. Results In this study, we demonstrate that acetylation at lysine K346 in the carboxy-terminal domain of Tax is modulated in the Tax nuclear bodies by the acetyltransferase p300 and the deacetylases HDAC5/7 and controls phosphorylation of the tumor suppressor pRb by Tax-cyclin D3-CDK4-p21CIP complexes. This property correlates with the inability of the acetylation deficient K346R mutant, but not the acetylation mimetic K346Q mutant, to promote anchorage-independent growth of Rat-1 fibroblasts. By contrast, acetylation at lysine K346 had no effects on the ability of Tax carboxy-terminal PDZ-binding domain to interact with the tumor suppressor hDLG. Conclusions The identification of the acetyltransferase p300 and the deacetylase HDAC7 as enzymes modulating Tax acetylation points to new therapeutic targets for the treatment of HTLV-1 infected patients at risk of developing ATL. [less ▲]

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See detailEffect of bio-sourced compounds on activation of immune cells in the view of to improve immunotherapy of malignant pleural mesothelioma
Hamaïdia, Malik ULg; Cosse, Jean-Philippe ULg; Willems, Luc ULg

Poster (2013, July)

Glycans are macromolecules (O-glycosidic and N-glycosidic linkage of monosacharides) which can be extracted from various agricultural products (i.e. cellulose, lignin, starch, insect). Preliminary data ... [more ▼]

Glycans are macromolecules (O-glycosidic and N-glycosidic linkage of monosacharides) which can be extracted from various agricultural products (i.e. cellulose, lignin, starch, insect). Preliminary data indicate that glycans can stimulate inflammation without initiating an anti-inflammatory feedback loop. Notwithstanding, inhibition of immune response by anti-inflammatory cytokines is a major cause of cancer therapy failure in human. The goal of the project is to study the ability of glycans to modulate the functions of macrophages and dendritic cells in order to stimulate anti-tumor immune response. The project aims to assess this hypothesis in a high incidence cancer: Malignant Pleural Mesothelioma. Glycan extracts will be isolated from a variety of agroforestry resources and especially broadleaved trees of the different systems tested on the platform AgricultureIsLife (zones 1-3 : hedges, tree lines, agrisilviculture, short rotation coppice) and modified by physical, chemical, enzymatic or microbiotic approaches. [less ▲]

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See detailMassive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites During Primary Infection
Gillet, Nicolas ULg; Gutiérrez, Gerónimo; Rodriguez, Sabrina et al

Conference (2013, June 29)

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See detailNovel phenolic glycolipids: antioxidant activity and effect on membrane models
Sainvitu, Pauline ULg; Nasir, Mehmet Nail ULg; Draguet, Florian et al

Poster (2013, May 30)

Aromatic glycolipids are of both medical as well as pharmaceutical interest. Antimicrobial, antiviraland antiinflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B ... [more ▼]

Aromatic glycolipids are of both medical as well as pharmaceutical interest. Antimicrobial, antiviraland antiinflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic). Moreover, they are expected to have interesting antioxidant properties when they contain phenolic groups. The alkyl chain should enhance their ability to penetrate into the cellular membrane (Nicolosi, 2002, Journal of Molecular Catalysis B: Enzymatic). The presence of a sugar unit could also be useful to target specific cells. In this study, novel aromatic glycolipids were synthesized as useful models for studying the structure–activity relationship, in particular as regards to their aromatic group.Theireffect on cell viability when an oxidative stress is induced was tested. In parallel, their interaction with cell models (liposomes) was studied through membrane fusion and permeability experiments. [less ▲]

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See detailBiophysical characterization of the interaction of novel aromatic glycolipid surfactants with membrane models.
Sainvitu, Pauline ULg; Nasir, Mehmet Nail ULg; Draguet, Florian et al

Poster (2013, May 15)

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic ... [more ▼]

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic). Moreover, they are expected to have interesting antioxidant properties when they contain phenolic groups. The alkyl chain should enhance their ability to penetrate into the cellular membrane (Nicolosi, 2002, Journal of Molecular Catalysis B: Enzymatic). The presence of a sugar unit could also be useful to target specific cells. In this study, novel aromatic glycolipids were synthesized as useful models for studying the structure–activity relationship, in particular as a function of their aromatic group. Their interaction with membranes was studied with monolayer models and was predicted by a computational approach. The relationships between these data and their cytotoxicity and antioxidant properties evaluated on cell cultures are discussed. [less ▲]

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See detailBiophysical characterization of the interaction of novel aromatic glycolipid surfactants with membrane models.
Sainvitu, Pauline ULg; Nasir, Mehmet Nail ULg; Nott, Katherine ULg et al

in World Academy of Science, Engineering and Technology (2013, May), 77

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic ... [more ▼]

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic). Moreover, they are expected to have interesting antioxidant properties when they contain phenolic groups. The alkyl chain should enhance their ability to penetrate into the cellular membrane (Nicolosi, 2002, Journal of Molecular Catalysis B: Enzymatic). The presence of a sugar unit could also be useful to target specific cells. In this study, novel aromatic glycolipids were synthesized as useful models for studying the structure–activity relationship, in particular as a function of their aromatic group. Their interaction with membranes was studied with monolayer models and was predicted by a computational approach. The relationships between these data and their cytotoxicity and antioxidant properties evaluated on cell cultures are discussed. [less ▲]

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See detailBiophysical characterization of the interaction of novel aromatic glycolipid surfactants with membrane models.
Sainvitu, Pauline ULg; Nasir, Mehmet Nail ULg; Nott, Katherine ULg et al

in World Academy of Science, Engineering and Technology (2013, May), 77

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic ... [more ▼]

Aromatic glycolipids are of both medical and pharmaceutical interest. Antimicrobial, antiviral and anti-inflammatory activities have been reported (Otto, 2000, Journal of Molecular Catalysis B: Enzymatic). Moreover, they are expected to have interesting antioxidant properties when they contain phenolic groups. The alkyl chain should enhance their ability to penetrate into the cellular membrane (Nicolosi, 2002, Journal of Molecular Catalysis B: Enzymatic). The presence of a sugar unit could also be useful to target specific cells. In this study, novel aromatic glycolipids were synthesized as useful models for studying the structure–activity relationship, in particular as a function of their aromatic group. Their interaction with membranes was studied with monolayer models and was predicted by a computational approach. The relationships between these data and their cytotoxicity and antioxidant properties evaluated on cell cultures are discussed. [less ▲]

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See detailViruses and Cancer
Barez, Pierre-Yves ULg; Carpentier, Alexandre ULg; Willems, Luc ULg

Conference (2013, February 08)

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See detailInteraction of HTLV-­1 Tax with minichromosome maintenance proteins accelerates the replication timing program
Carpentier, Alexandre ULg; Barez, Pierre-Yves ULg; Willems, Luc ULg

Conference (2013, January 28)

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about twenty million individuals worldwide. HTLV-1 is the causative agent of different diseases among which the most common are the ... [more ▼]

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about twenty million individuals worldwide. HTLV-1 is the causative agent of different diseases among which the most common are the adult T-cell leukemia (ATL) and a neurodegenerative disorder called HAM/TSP (Human associated myelopathy/ Tropical spastic paraparesis). A key parameter of HTLV-1 pathogenesis is faster replication of provirus-carrying lymphocytes allowing clonal expansion of infected cell populations. The virally-encoded Tax oncoprotein plays an essential role in this process by interacting with DNA replication origins and accelerating S phase progression. By reprogramming the timing of origin firing, Tax also creates a replicative stress leading to DNA double strand breaks. This mechanism further triggers the DNA damage response (DDR) that induces cell cycle arrest and initiates either apoptosis or senescence. However, HTLV-1 infected cells have developed strategies to interfere with the DDR and are adapted to checkpoint control. These cells are thus able to proliferate despite occurrence of DNA damage. Based on these observations, we now propose a novel therapeutic approach based on the principle of synthetic lethality. [less ▲]

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See detailWIP1 deficiency inhibits HTLV-1 Tax oncogenesis: novel therapeutic prospects for treatment of ATL?
Gillet, Nicolas ULg; Carpentier, Alexandre ULg; Barez, Pierre-Yves ULg et al

in Retrovirology (2012), 9(1), 115

Attenuation of p53 activity appears to be a major step in Human T-lymphotropic virus type 1 (HTLV-1) Tax transformation. However, p53 genomic mutations are late and rather infrequent events in HTLV-1 ... [more ▼]

Attenuation of p53 activity appears to be a major step in Human T-lymphotropic virus type 1 (HTLV-1) Tax transformation. However, p53 genomic mutations are late and rather infrequent events in HTLV-1 induced Adult T cell leukemia (ATL). The paper by Zane et al. shows that a mediator of p53 activity, Wild-type p53-induced phosphatase 1 (Wip1), contributes to Tax-induced oncogenesis in a mouse model. Wip1 may therefore be a novel target for therapeutic approaches. [less ▲]

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See detailReprogramming of replication origin firing and checkpoint adaptation in adult T cell leukemia
Barez, Pierre-Yves ULg; Carpentier, Alexandre ULg; Willems, Luc ULg

Conference (2012, December 14)

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about twenty million individuals worldwide. HTLV-1 is the causative agent of different diseases among which the most common are the ... [more ▼]

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about twenty million individuals worldwide. HTLV-1 is the causative agent of different diseases among which the most common are the adult T-cell leukemia (ATL) and a neurodegenerative disorder called HAM/TSP (Human associated myelopathy/ Tropical spastic paraparesis). A key parameter of HTLV-1 pathogenesis is faster replication of provirus-carrying lymphocytes allowing clonal expansion of infected cell populations. The virally-encoded Tax oncoprotein plays an essential role in this process by interacting with DNA replication origins and accelerating S phase progression. By reprogramming the timing of origin firing, Tax also creates a replicative stress leading to DNA double strand breaks. This mechanism further triggers the DNA damage response (DDR) that induces cell cycle arrest and initiates either apoptosis or senescence. However, HTLV-1 infected cells have developed strategies to interfere with the DDR and are adapted to checkpoint control. These cells are thus able to proliferate despite occurrence of DNA damage. Based on these observations, we now propose a novel therapeutic approach based on the principle of synthetic lethality. [less ▲]

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See detailTransformation by deltaretroviruses: mechanisms and therapies
Willems, Luc ULg

in Proceedings of the Belgian Royal Academies of Medicine (2012), 1

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million ... [more ▼]

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million subjects worldwide and causes Adult T-cell leukemia-lymphoma (ATLL) or HAM/TSP (HTLV-induced myelopathy - tropical spastic paraparesis). BLV is the etiological agent of enzootic bovine leukemia. HTLV-1 and BLV have developed strategies to subvert hosts' immune surveillance. Understanding these mechanisms has allowed development of novel therapeutic approaches. [less ▲]

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See detailTransformation by deltaretroviruses: mechanisms and therapies
Willems, Luc ULg

in Proceedings of the Belgian Royal Academies of Medicine (2012), 1

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million ... [more ▼]

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million subjects worldwide and causes Adult T-cell leukemia-lymphoma (ATLL) or HAM/TSP (HTLV-induced myelopathy - tropical spastic paraparesis). BLV is the etiological agent of enzootic bovine leukemia. HTLV-1 and BLV have developed strategies to subvert hosts' immune surveillance. Understanding these mechanisms has allowed development of novel therapeutic approaches. [less ▲]

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See detailTransformation by deltaretroviruses: mechanisms and therapies
Willems, Luc ULg

in Proceedings of the Belgian Royal Academies of Medicine (2012), 1

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million ... [more ▼]

Human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are two closely related deltaretroviruses inducing hematological diseases in human and ruminants. HTLV-1 infects about 25 million subjects worldwide and causes Adult T-cell leukemia-lymphoma (ATLL) or HAM/TSP (HTLV-induced myelopathy - tropical spastic paraparesis). BLV is the etiological agent of enzootic bovine leukemia. HTLV-1 and BLV have developed strategies to subvert hosts' immune surveillance. Understanding these mechanisms has allowed development of novel therapeutic approaches. [less ▲]

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See detailSynthesis and physico-chemical characterization of fatty esters
Sainvitu, Pauline ULg; Nott, Katherine ULg; Nicks, Francois ULg et al

Poster (2012, November 16)

Specific antioxidant molecules (e.g. phenolics) help to prevent oxidation reaction of the cell membrane. A fatty chain grafted on these compounds should enhance their capacity to interact with the ... [more ▼]

Specific antioxidant molecules (e.g. phenolics) help to prevent oxidation reaction of the cell membrane. A fatty chain grafted on these compounds should enhance their capacity to interact with the membrane lipids. In our study, three fatty esters comprising an aromatic part were synthesized. They differentiate the aromatic substituent and the number of carbons between the aromatic ring and the ester function. A structure-function relationships study was performed to identify the structural pattern affecting the interfacial properties and the membrane interaction properties. The behavior of their monolayer film at an air-water interface was studied. The interactions with membrane were assessed on living cells and were predicted by a computational approach. In the future, we will investigate the effect of the presence of a sugar unit on these molecules. [less ▲]

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See detailChemoresistance to Valproate Treatment of Bovine Leukemia Virus-Infected Sheep; Identification of Improved HDAC Inhibitors
Gillet, Nicolas ULg; Vandermeers, Fabian ULg; De Brogniez, Alix ULg et al

in Pathogens (2012), (2012-1), 65-82

We previously proved that a histone deacetylase inhibitor (valproate, VPA) decreases the number of leukemic cells in bovine leukemia virus (BLV)-infected sheep. Here, we characterize the mechanisms ... [more ▼]

We previously proved that a histone deacetylase inhibitor (valproate, VPA) decreases the number of leukemic cells in bovine leukemia virus (BLV)-infected sheep. Here, we characterize the mechanisms initiated upon interruption of treatment. We observed that VPA treatment is followed by a decrease of the B cell counts and proviral loads (copies per blood volume). However, all sheep eventually relapsed after different periods of time and became refractory to further VPA treatment. Sheep remained persistently infected with BLV. B lymphocytes isolated throughout treatment and relapse were responsive to VPA-induced apoptosis in cell culture. B cell proliferation is only marginally affected by VPA ex vivo. Interestingly, in four out of five sheep, ex vivo viral expression was nearly undetectable at the time of relapse. In two sheep, a new tumoral clone arose, most likely revealing a selection process exerted by VPA in vivo. We conclude that the interruption of VPA treatment leads to the resurgence of the leukemia in BLV-infected sheep and hypothesize that resistance to further treatment might be due to the failure of viral expression induction. The development of more potent HDAC inhibitors and/or the combination with other compounds can overcome chemoresistance. These observations in the BLV model may be important for therapies against the related Human T-lymphotropic virus type 1. [less ▲]

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