Publications of Luc Willems
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See detailTGFα Promotes Chemoresistance of Malignant Pleural Mesothelioma
Staumont, Bernard ULiege; Jamakhani, Majeed ULiege; Costa, Chrisostome et al

in Cancers (2020), 12(6), 1484

Background: There is no standard chemotherapy for refractory or relapsing malignant pleural mesothelioma (MPM). Our previous reports nevertheless indicated that a combination of an anthracycline ... [more ▼]

Background: There is no standard chemotherapy for refractory or relapsing malignant pleural mesothelioma (MPM). Our previous reports nevertheless indicated that a combination of an anthracycline (doxorubicin) and a lysine deacetylase inhibitor (valproic acid, VPA) synergize to induce the apoptosis of MPM cells and reduce tumor growth in mouse models. A Phase I/II clinical trial indicated that this regimen is a promising therapeutic option for a proportion of MPM patients. Methods: The transcriptomes of mesothelioma cells were compared after Illumina HiSeq 4000 sequencing. The expression of differentially expressed genes was inhibited by RNA interference. Apoptosis was determined by cell cycle analysis and Annexin V/7-AAD labeling. Protein expression was assessed by immunoblotting. Preclinical efficacy was evaluated in BALB/c and NOD-SCID mice. Results: To understand the mechanisms involved in chemoresistance, the transcriptomes of two MPM cell lines displaying different responses to VPA-doxorubicin were compared. Among the differentially expressed genes, transforming growth factor alpha (TGFα) was associated with resistance to this regimen. The silencing of TGFα by RNA interference correlated with a significant increase in apoptosis, whereas the overexpression of TGFα desensitized MPM cells to the apoptosis induced by VPA and doxorubicin. The multi-targeted inhibition of histone deacetylase (HDAC), HER2 and TGFα receptor (epidermal growth factor receptor/EGFR) improved treatment efficacy in vitro and reduced tumor growth in two MPM mouse models. Finally, TGFα expression but not EGFR correlated with patient survival. Conclusions: Our data show that TGFα but not its receptor EGFR is a key factor in resistance to MPM chemotherapy. This observation may contribute to casting light on the promising but still controversial role of EGFR signaling in MPM therapy. [less ▲]

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See detailAblation of non-coding RNAs affects bovine leukemia virus B lymphocyte proliferation and abrogates oncogenesis
Safari, Roghaiyeh; Jacques, Jean-Rock; Brostaux, Yves ULiege et al

in PLoS Pathogens (2020)

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See detailORF Capture-Seq as a versatile method for targeted identification of full-length isoforms
Sheynkman, G. M.; Tuttle, K. S.; Laval, Florent ULiege et al

in Nature Communications (2020), 11(1),

Most human protein-coding genes are expressed as multiple isoforms, which greatly expands the functional repertoire of the encoded proteome. While at least one reliable open reading frame (ORF) model has ... [more ▼]

Most human protein-coding genes are expressed as multiple isoforms, which greatly expands the functional repertoire of the encoded proteome. While at least one reliable open reading frame (ORF) model has been assigned for every coding gene, the majority of alternative isoforms remains uncharacterized due to (i) vast differences of overall levels between different isoforms expressed from common genes, and (ii) the difficulty of obtaining full-length transcript sequences. Here, we present ORF Capture-Seq (OCS), a flexible method that addresses both challenges for targeted full-length isoform sequencing applications using collections of cloned ORFs as probes. As a proof-of-concept, we show that an OCS pipeline focused on genes coding for transcription factors increases isoform detection by an order of magnitude when compared to unenriched samples. In short, OCS enables rapid discovery of isoforms from custom-selected genes and will accelerate mapping of the human transcriptome. © 2020, The Author(s). [less ▲]

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See detailBta-miR-24-3p Controls the Myogenic Differentiation and Proliferation of Fetal, Bovine, Skeletal Muscle-Derived Progenitor Cells by Targeting ACVR1B
Hu, Xin; Xing, Yishen; Ren, Ling et al

in Animals (2019)

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this ... [more ▼]

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this study, we report that bta-miR-24-3p promotes the myogenic di erentiation of fetal bovine PDGFR - progenitor cells. The expression of bta-miR-24-3p increased during myogenic differentiation. Overexpression of bta-miR-24-3p significantly promoted myogenic di erentiation, but inhibited proliferation. A dual-luciferase assay identified ACVR1B as a direct target of bta-miR-24-3p. Similarly, knocking down ACVR1B by RNA interference also significantly inhibited proliferation and promoted the di erentiation of bovine PDGFR - progenitor cells. Thus, our study provides a mechanism in which bta-miR-24-3p regulates myogenesis by inhibiting ACVR1B expression. [less ▲]

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See detailBLV: lessons on vaccine development
Abdala, Alejandro; Alvarez, Irene; Brossel, Hélène ULiege et al

in Retrovirology (2019), 2019(16), 26

Vaccination against retroviruses is a challenge because of their ability to stably integrate into the host genome, undergo long-term latency in a proportion of infected cells and thereby escape immune ... [more ▼]

Vaccination against retroviruses is a challenge because of their ability to stably integrate into the host genome, undergo long-term latency in a proportion of infected cells and thereby escape immune response. Since clearance of the virus is almost impossible once infection is established, the primary goal is to achieve sterilizing immunity. Besides efcacy, safety is the major issue since vaccination has been associated with increased infection or reversion to pathogenicity. In this review, we discuss the diferent issues that we faced during the development of an efcient vaccine against bovine leukemia virus (BLV). We summarize the historical failures of inactivated vaccines, the efcacy and safety of a live-attenuated vaccine and the economical constraints of further industrial development. [less ▲]

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See detailAstin C production by the endophytic fungus Cyanodermella asteris in planktonic and immobilized culture conditions
Vassaux, Antoine ULiege; Tarayre, Cédric; Arguelles Arias, Anthony ULiege et al

in Biotechnology Journal (2019)

The fungal endophyte Cyanodermella asteris was recently isolated from the medicinal plant Aster tataricus. This fungus produces astin C, a cyclic pentapeptide with anticancer and anti-inflammatory ... [more ▼]

The fungal endophyte Cyanodermella asteris was recently isolated from the medicinal plant Aster tataricus. This fungus produces astin C, a cyclic pentapeptide with anticancer and anti-inflammatory properties. The production of this secondary metabolite was compared in immobilized and planktonic conditions. For immobilized cultures, a stainless steel packing immersed in the culture broth was used as a support. In these conditions, the fungus exclusively grew on the packing, which provides a considerable advantage for astin C recovery and purification. C. asteris metabolism was different according to the culture conditions in terms of substrate consumption rate, cell-growth, and astin C production. Immobilized-cell cultures yielded a 30% increase of astin C production associate to a 39% increase in biomass. The inoculum type as spores rather than hyphae, and a pre-inoculation washing procedure with sodium hydroxide, turned out to be beneficial both for astin C production and fungus development onto the support. Finally, influence of culture parameters such as pH and medium composition, on astin C production was evaluated. With optimized culture conditions, astin C yield was further improved reaching a five times higher final specific yield compared to the value reported with astin C extraction from Aster tataricus (0.89 and 0.16 mg/g respectively). [less ▲]

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See detailInhibition of EZH2 methyltransferase decreases immunoediting of mesothelioma cells by autologous macrophages through a PD-1-dependent mechanism.
Hamaïdia, Malik ULiege; Gazon, Hélène ULiege; Hoyos, Clotilde ULiege et al

in JCI Insight (2019), 4(18),

The roles of macrophages in orchestrating innate immunity through phagocytosis and T lymphocyte activation have been extensively investigated. Much less understood is the unexpected role of macrophages in ... [more ▼]

The roles of macrophages in orchestrating innate immunity through phagocytosis and T lymphocyte activation have been extensively investigated. Much less understood is the unexpected role of macrophages in direct tumor regression. Tumoricidal macrophages can indeed manifest cancer immunoediting activity in the absence of adaptive immunity. We investigated direct macrophage cytotoxicity in malignant pleural mesothelioma, a lethal cancer that develops from mesothelial cells of the pleural cavity after occupational asbestos exposure. In particular, we analyzed the cytotoxic activity of mouse RAW264.7 macrophages upon cell-cell contact with autologous AB1/AB12 mesothelioma cells. We show that macrophages killed mesothelioma cells by oxeiptosis via a mechanism involving enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27-specific (H3K27-specific) methyltransferase of the polycomb repressive complex 2 (PRC2). A selective inhibitor of EZH2 indeed impaired RAW264.7-directed cytotoxicity and concomitantly stimulated the PD-1 immune checkpoint. In the immunocompetent BALB/c model, RAW264.7 macrophages pretreated with the EZH2 inhibitor failed to control tumor growth of AB1 and AB12 mesothelioma cells. Blockade of PD-1 engagement restored macrophage-dependent antitumor activity. We conclude that macrophages can be directly cytotoxic for mesothelioma cells independent of phagocytosis. Inhibition of the PRC2 EZH2 methyltransferase reduces this activity because of PD-1 overexpression. Combination of PD-1 blockade and EZH2 inhibition restores macrophage cytotoxicity. [less ▲]

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See detailGenomic sequence and virulence of a novel NADC30-like porcine reproductive and respiratory syndrome virus isolate from the Hebei province of China
Xiukun, Sui; Xiaoyu, Guo; Hong, Jia et al

in Microbial Pathogenesis (2018), 125

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS), which results in immense economic losses in the swine industry ... [more ▼]

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS), which results in immense economic losses in the swine industry. Outbreaks of disease caused by NADC30-like PRRSV are of great concern in China. Here, a novel variant, NADC30-like PRRSV strain HB17A, was analyzed and its pathogenicity in pigs was examined. The full-length genome sequence of HB17A shared 83.6–95.1% nucleotide similarity with NADC30-like and NADC30 PRRSV without any gene insertions, but with a unique 2-amino acid deletion in Nsp2. A phylogenetic analysis showed that HB17A clustered with NADC30 strains. Different degrees of variation in the signal peptide, transmembrane region (TM), primary neutralizing epitope (PNE), non-neutral epitopes, and N-glycosylation sites were observed in GP5. Challenge experiments showed that HB17A infection resulted in persistent fever, moderate respiratory clinical signs, low levels of viremia and viral loads in serum, and mild gross and microscopic lung lesions. Moreover, IFN-γ, IL-6, and IL-10 cytokine levels were significantly elevated in serum, but the levels of IFN-α and IL-2 were similar to those of the negative controls. HB17A was less pathogenic but was secreted longer in nasal discharge than HP-PRRSV FZ06A. Our findings indicate that HB17A is a novel NADC30-like strain with certain deletions and mutations but with no evidence of genomic recombination. This strain exhibits intermediate virulence in pigs. This research will be help define the evolutionary characteristics of Chinese NADC30-like PRRSV. [less ▲]

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See detailInterlaboratory Comparison of Six Real-Time PCR Assays for Detection of Bovine Leukemia Virus Proviral DNA
Jaworski, J. P.; Pluta, A.; Rola-Łuszczak, M. et al

in Journal of Clinical Microbiology (2018), 56(7),

Quantitative real-time PCR (qPCR) is increasingly being used for the detection of bovine leukemia virus (BLV) proviral DNA. Nevertheless, quality control for the validation and standardization of such ... [more ▼]

Quantitative real-time PCR (qPCR) is increasingly being used for the detection of bovine leukemia virus (BLV) proviral DNA. Nevertheless, quality control for the validation and standardization of such tests is currently lacking. Therefore, the present study was initiated by three Office International des Epizooties (OIE) reference laboratories and three collaborating laboratories to measure the interlaboratory variability of six already developed and available BLV qPCR assays. For that purpose, an international panel of 58 DNA samples reflecting the dynamic range of the majority of the assays was distributed to six testing centers. Based on qualitative results, the overall agreement among all six laboratories was moderate. However, significant variability in the measurement of the BLV proviral DNA copy number was observed among different laboratories. Quantitative PCR assays, even when performed by experienced staff, can yield large variability in BLV proviral DNA copy numbers without harmonization. Further standardization of different factors (i.e., utilization of unified protocols and unique calibrators) should increase interlaboratory agreement. [less ▲]

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See detailHow Does HTLV-1 Undergo Oncogene-Dependent Replication Despite a Strong Immune Response?
Gazon, Hélène ULiege; Chauhan, Pradeep Singh ULiege; Hamaïdia, Malik ULiege et al

in Frontiers in Microbiology (2018), 8

In 1987, Mitsuaki Yoshida proposed the following model (Yoshida and Seiki, 1987): “... T-cells activated through the endogenous p40x would express viral antigens including the envelope glycoproteins which ... [more ▼]

In 1987, Mitsuaki Yoshida proposed the following model (Yoshida and Seiki, 1987): “... T-cells activated through the endogenous p40x would express viral antigens including the envelope glycoproteins which are exposed on the cell surface. These glycoproteins are targets of host immune surveillance, as is evidenced by the cytotoxic effects of antienvelope antibodies or patient sera. Eventually all cells expressing the viral antigens, that is, all cells driven by the p40x would be rejected by the host. Only those cells that did not express the viral antigens would survive. Later, these antigen-negative infected cells would begin again to express viral antigens, including p40x, thus entering into the second cycle of cell propagation. These cycles would be repeated in so-called healthy virus carriers for 20 or 30 years or longer....” Three decades later, accumulated experimental facts particularly on intermittent viral transcription and regulation by the host immune response appear to prove that Yoshida was right. This Hypothesis and Theory summarizes the evidences that support this paradigm. [less ▲]

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See detailTumor cells may circulate in medullary thyroid cancer patients independently of serum calcitonin
Sriramareddy, S; HAMOIR, Etienne ULiege; CHAVEZ, Viviana ULiege et al

in Endocrine-Related Cancer (2018), 25(12),

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See detailPositioning Europe for the EPITRANSCRIPTOMICS challenge
Jantsch, Michael F; Quattrone, Alessandro; O'Connell, Mary et al

in RNA Biology (2018), 15

The genetic alphabet consists of the four letters: C, A, G, and T in DNA and C,A,G, and U in RNA. Triplets of these four letters jointly encode 20 different amino acids out of which proteins of all ... [more ▼]

The genetic alphabet consists of the four letters: C, A, G, and T in DNA and C,A,G, and U in RNA. Triplets of these four letters jointly encode 20 different amino acids out of which proteins of all organisms are built. This system is universal and is found in all kingdoms of life. However, bases in DNA and RNA can be chemically modified. In DNA, around 10 different modifications are known, and those have been studied intensively over the past 20 years. Scientific studies on DNA modifications and proteins that recognize them gave rise to the large field of epigenetic and epigenomic research. The outcome of this intense research field is the discovery that development, ageing, and stem-cell dependent regeneration but also several diseases including cancer are largely controlled by the epigenetic state of cells. Consequently, this research has already led to the first FDA approved drugs that exploit the gained knowledge to combat disease. In recent years, the ~150 modifications found in RNA have come to the focus of intense research. Here we provide a perspective on necessary and expected developments in the fast expanding area of RNA modifications, termed epitranscriptomics. [less ▲]

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See detailGenomic characterization and pathogenic study of two porcine reproductive and respiratory syndrome viruses with different virulence in Fujian, China
Xiukun, Sui; Ting, Xin; Xiaoyu, Guo et al

in Journal of Veterinary Science (2018), 19(3), 339-349

Two strains of porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in 2006 and 2016 and designated as FZ06A and FZ16A, respectively. Inoculation experiments showed that FZ06A caused ... [more ▼]

Two strains of porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in 2006 and 2016 and designated as FZ06A and FZ16A, respectively. Inoculation experiments showed that FZ06A caused 100% morbidity and 60% mortality, while FZ16A caused 100% morbidity without death. By using genomic sequence and phylogenetic analyses, close relationships between a Chinese highly pathogenic PRRSV strain and the FZ06A and FZ16A strains were observed. Based on the achieved results, multiple genomic variations in Nsp2, a unique N-glycosylation site (N33→K33), and a K151 amino acid (AA) substitution for virulence in the GP5 of FZ16A were detected; except the 30 AA deletion in the Nsp2-coding region. Inoculation experiments were conducted and weaker virulence of FZ16A than FZ06A was observed. Based on our results, a 30 AA deletion in the Nsp2-coding region is an unreliable genomic indicator of a high virulence PRRSV strain. The Nsp2 and GP5 differences, in addition to the virulence difference between these two highly pathogenic PRRSV strains, have the potential to be used to establish a basis for further study of PRRSV virulence determinants and to provide data useful in the development of vaccines against this economically devastating disease. [less ▲]

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See detailTime to Go Back to the Original Name
Gallo, Robert; Willems, Luc ULiege; Tagaya, Yutaka

in Frontiers in Microbiology (2017), 8

Almost 40 years ago, the first pathogenic human retrovirus was discovered and shown to cause a T-cell leukemia in humans (Poiesz et al., 1980a, 1981). Thus, a new paradigm was established showing that a ... [more ▼]

Almost 40 years ago, the first pathogenic human retrovirus was discovered and shown to cause a T-cell leukemia in humans (Poiesz et al., 1980a, 1981). Thus, a new paradigm was established showing that a virus can directly cause cancer in humans. At that time, the only other suspected case was the connection between the Epstein-Barr Virus (EBV) and Burkitt’s Lymphoma and later nasopharyngeal carcinoma. Naturally, and in keeping with the names used for animal retroviruses associated with leukemia, we (the Gallo group) named this new virus as human T-cell leukemia virus (HTLV), which was formally accepted by the scientific community. As of today, our list of human oncogenic viruses has expanded to include hepatitis B/C virus (HBV, HCV), papillomaviruses (HPV), Herpes virus-8 (HHV-8), and Merkel cell polyomavirus (MCV). In parallel, the group of Delta-retroviruses that HTLV belongs to has expanded to accommodate additionalmembers over the years, now consisting ofHTLV-1_4, and STLV-1_4. In themeantime, the name of the original virus was changed to human T-lymphotropic virus-1, because of the addition of the viral causative agent of AIDS as HTLV-III to the same group (Coffin, 2015). Thus, one of us (RCG) agreed on this name change with several other retrovirologists at a Cold-Spring Harbor meeting in 1983. In retrospect, the name change has made it ambiguous as to which virus should enter this group, and since the AIDS virus was formally named HIV and separated from the HTLV group, making the need for the name of HTLV-1 as human T-“lymphotropic” virus no longer particularly useful or meaningful. Finally, we note here the greater oncogenicity of HTLV-1 compared to other viruses, or even other known carcinogens which is a point in keeping a name that describes their effect (discussed in an accompanying article). Therefore, we propose to restore the original name “leukemia virus.” [less ▲]

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See detailInhibition studies of DNA methyltransferases by maleimide derivatives of RG108 as non-nucleoside inhibitors
Rondelet, Grégoire; Fleury, Laurence; Faux, Céline et al

in Future Medicinal Chemistry (2017), 9(13),

Aim: DNA methyltransferases (DNMTs) are important drug targets for epigenetic therapy of cancer. Nowadays, non-nucleoside DNMT inhibitors are in development to address high toxicity of nucleoside analogs ... [more ▼]

Aim: DNA methyltransferases (DNMTs) are important drug targets for epigenetic therapy of cancer. Nowadays, non-nucleoside DNMT inhibitors are in development to address high toxicity of nucleoside analogs. However, these compounds still have low activity in cancer cells and mode of action of these compounds remains unclear. Materials & methods: In this work, we studied maleimide derivatives of RG108 by biochemical, structural and computational approaches to highlight their inhibition mechanism on DNMTs. Results: Findings demonstrated a correlation between cytotoxicity on mesothelioma cells of these compounds and their inhibitory potency against DNMTs. Noncovalent and covalent docking studies, supported by crystallographic (apo structure of M.HhaI) and differential scanning fluorimetry assays, provided detailed insights into their mode of action and revealed essential residues for the stabilization of such compounds inside DNMTs. [less ▲]

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