References of "Peulen, Olivier"
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See detailMyoferlin, a new autophagy player in pancreatic cancer cells
Rademaker, Gilles ULg; Hennequière, Vincent ULg; Peixoto, Paul et al

Poster (2017, February 01)

Despite intensive research, Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the deadliest forms of cancer. Early-stage of the disease is clinically silent and the diagnosis of the disease is mostly ... [more ▼]

Despite intensive research, Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the deadliest forms of cancer. Early-stage of the disease is clinically silent and the diagnosis of the disease is mostly made at an advanced stage. This late diagnosis contributes to one of the lowest 5-year survival rates (<5%). Today, PDAC are treated by surgery and/or adjuvant therapy, increasing only slightly the median survival of the patients. There is therefore an urgent need to develop new effective therapies for PDAC patients. PDAC are characterized by a high autophagic activity involved in its chemoresistance. Recently, key regulatory proteins controlling the metabolic reprogramming of PDAC cells were identified. By governing both autophagic flux and lysosomal catabolism, these proteins support the efficient processing of cargo from autophagy, providing PDAC cells with access to critical sources of nutrients. Interestingly, the high autophagy level in PDAC correlates with a poor patient outcome. Myoferlin, a member of the ferlin family overexpressed at protein level in different cancer types including PDAC, is a transmembrane protein able to bound to phospholipids and described to play an important function in membrane fusion. This characteristic invited us to investigate whether myoferlin could participate to autophagy, a process involving membrane fusion. Panc-1 cell line was used as a model of PDAC basal autophagy. Myoferlin expression was silenced using interfering RNA technology. Autophagosome abundance was evaluated by LC3-II western-blot and flow cytometry. Results indicated a significant increase in autophagosome abundance 48 h after myoferlin-silencing. This increase could arise from an increase of autophagy initiation or from an inhibition of autolysosome degradation. Using autophagy inhibitors, autophagic flux was evaluated by LC3-II and p62 western-blot after myoferlin-silencing. Results suggested a blockade in the autophagic process, impairing termination and autophagosome degradation by lysosome activity. Knowing the affinity of myoferlin for phospholipids, we wonder if this protein could interact with the phosphatidylethanolamine-conjugated LC3-II protein. Proximity-ligation assay suggested a close interaction between myoferlin and LC3. These results evoke an unexplored and undescribed role for myoferlin in autophagy. Understanding the involvement of myoferlin in this rediscovered biological process could give new clues in the development of new therapeutic strategy. [less ▲]

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See detailMethylglyoxal-Mediated Stress Correlates with High Metabolic Activity and Promotes Tumor Growth in Colorectal Cancer.
Chiavarina, Barbara ULg; Nokin, Marie-Julie ULg; Bellier, Justine ULg et al

in International Journal of Molecular Sciences (2017), 18(1),

Cancer cells generally rely on aerobic glycolysis as a major source of energy. Methylglyoxal (MG), a dicarbonyl compound that is produced as a side product during glycolysis, is highly reactive and ... [more ▼]

Cancer cells generally rely on aerobic glycolysis as a major source of energy. Methylglyoxal (MG), a dicarbonyl compound that is produced as a side product during glycolysis, is highly reactive and induces the formation of advanced glycation end-products that are implicated in several pathologies including cancer. All mammalian cells have an enzymatic defense against MG composed by glyoxalases GLO1 and GLO2 that converts MG to d-lactate. Colorectal cancer (CRC) is one of the most frequently occurring cancers with high morbidity and mortality. In this study, we used immunohistochemistry to examine the level of MG protein adducts, in a series of 102 CRC human tumors divided into four clinical stages. We consistently detected a high level of MG adducts and low GLO1 activity in high stage tumors compared to low stage ones suggesting a pro-tumor role for dicarbonyl stress. Accordingly, GLO1 depletion in CRC cells promoted tumor growth in vivo that was efficiently reversed using carnosine, a potent MG scavenger. Our study represents the first demonstration that MG adducts accumulation is a consistent feature of high stage CRC tumors. Our data point to MG production and detoxification levels as an important molecular link between exacerbated glycolytic activity and CRC progression. [less ▲]

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See detailPEGylated and Functionalized Aliphatic Polycarbonate Polyplex Nanoparticles for Intravenous Administration of HDAC5 siRNA in Cancer Therapy
Frère, Antoine ULg; Baroni, Alexandra; Hendrick, Elodie ULg et al

in ACS Applied Materials and Interfaces (2017), 25(9(3)), 2181-2195

Guanidine and morpholine functionalized aliphatic polycarbonate polymers are able to efficiently deliver histone deacetylase 5 (HDAC5) siRNA into the cytoplasm of cancer cells in vitro leading to a ... [more ▼]

Guanidine and morpholine functionalized aliphatic polycarbonate polymers are able to efficiently deliver histone deacetylase 5 (HDAC5) siRNA into the cytoplasm of cancer cells in vitro leading to a decrease of cell proliferation were previously developed. To allow these biodegradable and biocompatible polyplex nanoparticles to overcome the extracellular barriers and be effective in vivo after an intravenous injection, polyethylene glycol chains (PEG750 or PEG2000) were grafted on the polymer structure. These nanoparticles, showed an average size of about 150 nm and a slightly positive zeta potential with complete siRNA complexation. Behavior of PEGylated and non-PEGylated polyplexes were investigated in the presence of serum, in terms of siRNA complexation (Fluorescence Correlation Spectroscopy), size (Dynamic Light Scattering and Single-Particle Tracking), interaction with proteins (Isothermal Titration Calorimetry) and cellular uptake. Surprisingly, both PEGylated and non-PEGylated formulations presented relatively good behavior in the presence of fetal bovine serum (FBS). Hemocompatibility tests showed no effect of these polyplexes on hemolysis and coagulation. In vivo biodistribution in mice was performed and showed a better siRNA accumulation at the tumor site for PEGylated polyplexes. However, cellular uptake in protein-rich conditions showed that PEGylated polyplex lost their ability to interact with biological membranes and enter into cells, showing the importance to perform in vitro investigations in physiological conditions closed to in vivo situation. In vitro, the efficiency of PEGylated nanoparticles decreases compared to non-PEGylated particles, leading to the loss of the antiproliferative effect on cancer cells. [less ▲]

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See detailMyoferlin is a novel exosomal protein and functional regulator of cancer-derived exosomes
Blomme, Arnaud; Fahmy, Karim; Peulen, Olivier ULg et al

in Oncotarget (2016)

Exosomes are communication mediators participating in the intercellular exchange of proteins, metabolites and nucleic acids. Recent studies have demonstrated that exosomes are characterized by a unique ... [more ▼]

Exosomes are communication mediators participating in the intercellular exchange of proteins, metabolites and nucleic acids. Recent studies have demonstrated that exosomes are characterized by a unique proteomic composition that is distinct from the cellular one. The mechanisms responsible for determining the proteome content of the exosomes remain however obscure. In the current study we employ ultrastructural approach to validate a novel exosomal protein myoferlin. This is a multiple C2-domain containing protein, known for its conserved physiological function in endocytosis and vesicle fusion biology. Emerging studies demonstrate that myoferlin is frequently overexpressed in cancer, where it promotes cancer cell migration and invasion. Our data expand these ndings by showing that myoferlin is a general component of cancer cell derived exosomes from different breast and pancreatic cancer cell lines. Using proteomic analysis, we demonstrate for the rst time that myoferlin depletion in cancer cells leads to a signi cantly modulated exosomal protein load. Such myoferlin-depleted exosomes were also functionally de cient as shown by their reduced capacity to transfer nucleic acids to human endothelial cells (HUVEC). Beyond this, myoferlin-depleted cancer exosomes also had a signi cantly reduced ability to induce migration and proliferation of HUVEC. The present study highlights myoferlin as a new functional player in exosome biology, calling for novel strategies to target this emerging oncogene in human cancer. [less ▲]

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See detailMyoferlin regulates cellular lipid metabolism and promotes metastases in triple-negative breast cancer
Blomme, Arnaud; Costanza, Brunella ULg; De Tullio, Pascal ULg et al

in Oncogene (2016)

Myoferlin is a multiple C2-domain-containing protein that regulates membrane repair, tyrosine kinase receptor function and endocytosis in myoblasts and endothelial cells. Recently it has been reported as ... [more ▼]

Myoferlin is a multiple C2-domain-containing protein that regulates membrane repair, tyrosine kinase receptor function and endocytosis in myoblasts and endothelial cells. Recently it has been reported as overexpressed in several cancers and shown to contribute to proliferation, migration and invasion of cancer cells. We have previously demonstrated that myoferlin regulates epidermal growth factor receptor activity in breast cancer. In the current study, we report a consistent overexpression of myoferlin in triple-negative breast cancer cells (TNBC) over cells originating from other breast cancer subtypes. Using a combination of proteomics, metabolomics and electron microscopy, we demonstrate that myoferlin depletion results in marked alteration of endosomal system and metabolism. Mechanistically, myoferlin depletion caused impaired vesicle traffic that led to a misbalance of saturated/unsaturated fatty acids. This provoked mitochondrial dysfunction in TNBC cells. As a consequence of the major metabolic stress, TNBC cells rapidly triggered AMP activated protein kinase-mediated metabolic reprogramming to glycolysis. This reduced their ability to balance between oxidative phosphorylation and glycolysis, rendering TNBC cells metabolically inflexible, and more sensitive to metabolic drug targeting in vitro. In line with this, our in vivo findings demonstrated a significantly reduced capacity of myoferlin-deficient TNBC cells to metastasise to lungs. The significance of this observation was further supported by clinical data, showing that TNBC patients whose tumors overexpress myoferlin have worst distant metastasis-free and overall survivals. This novel insight into myoferlin function establishes an important link between vesicle traffic, cancer metabolism and progression, offering new diagnostic and therapeutic concepts to develop treatments for TNBC patients. [less ▲]

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See detailNew role of osteopontin in DNA repair and impact on human glioblastoma radiosensitivity
Henry, Aurélie ULg; Nokin, Marie-Julie ULg; Leroi, Natacha ULg et al

in Oncotarget (2016)

Glioblastoma (GBM) represents the most aggressive and common solid human brain tumor. We have recently demonstrated the importance of osteopontin (OPN) in the acquisition/maintenance of stemness ... [more ▼]

Glioblastoma (GBM) represents the most aggressive and common solid human brain tumor. We have recently demonstrated the importance of osteopontin (OPN) in the acquisition/maintenance of stemness characters and tumorigenicity of glioma initiating cells. Consultation of publicly available TCGA database indicated that high OPN expression correlated with poor survival in GBM patients. In this study, we explored the role of OPN in GBM radioresistance using an OPN-depletion strategy in U87-MG, U87-MG vIII and U251-MG human GBM cell lines. Clonogenic experiments showed that OPN-depleted GBM cells were sensitized to irradiation. In comet assays, these cells displayed higher amounts of unrepaired DNA fragments post-irradiation when compared to control. We next evaluated the phosphorylation of key markers of DNA double-strand break repair pathway. Activating phosphorylation of H2AX, ATM and 53BP1 was signi cantly decreased in OPN-de cient cells. The addition of recombinant OPN prior to irradiation rescued phospho-H2AX foci formation thus establishing a new link between DNA repair and OPN expression in GBM cells. Finally, OPN knockdown improved mice survival and induced a signi cant reduction of heterotopic human GBM xenograft when combined with radiotherapy. This study reveals a new function of OPN in DNA damage repair process post-irradiation thus further con rming its major role in GBM aggressive disease. [less ▲]

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See detailOsteopontin predicts radiotherapy response of glioblastoma patients : new role in DNA damage repair
Henry, Aurélie ULg; Nokin, Marie-Julie; Leroi, Natacha ULg et al

Conference (2016, March 22)

- Introduction: Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These ... [more ▼]

- Introduction: Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments include maximal surgical resection, radiotherapy and concomitant or adjuvant chemotherapy with Temozolomide. However, the prognosis of adult patients with GBM remains poor and the survival outcome after treatment does not exceed 15 months. GBM-composing cells have developed many strategies to counteract these current therapies. Among the wide hallmarks acquired to survive, high osteopontin (OPN) expression correlates with lower overall and disease-free/relapse-free survival in all tumors combined, as well in brain cancer. Our recent study (Lamour V and Henry A, IJC 2015) has demonstrated the role of OPN in the tumorigenicity of glioblastoma cells and its importance in the maintenance of the stem characters. In the continuation of this work, our recent studies focused on the potential role of OPN in the resistance of GBM cells to radiotherapy and its potential implication in the initiation of Double Strand Breaks (DSBs) repair mechanisms. - Aims: In the context of this study, different GBM cell lines (U251-MG, U87-MG and U87 Viii) were used to assess the role of OPN in the initiation of the DSBs repair mechanism after an exposure to gamma-irradiation. - Methods and results: We performed the transient transfection of different GBM cell lines (U251-MG, U87-MG and U87-MG overexpressing EGFR VIII) with siRNAs specifically directed against OPN. After irradiation, all these OPN-depleted cells consistently showed a lower induction of γ–H2AX compared to control (irrelevant siRNA) as evidenced by western blot and immunofluorescence techniques. Thereafter, clonogenic assays allowed to prove that the survival of OPN-depleted cells was affected after an exposure to irradiation. To assess the importance of OPN expression in the response to radiotherapy, an heterotopic xenograft model was used. In brief, IPTG-inducible U87 shOPN clones were injected subcutaneously in NOD-SCID mice and were allowed to form a tumor. When average tumor volume reached a predetermined size range, mice were treated (or not) with IPTG by intraperitoneal injection during five days. At the end of the treatment, tumors were selectively exposed to gamma-irradiation by using a small animal irradiator X-RAD 225Cx (Precision X-Ray Inc., North Branford, CT). One week later, mice were sacrificed and tumors were measured. In this pilot study, we observed that mice in which the tumor was depleted in OPN displayed a slight regression in the tumor growth compared to mice that received radiotherapy alone (no IPTG), where the tumor volume remained constant. - Conclusions: Taken together, these preliminary data meet the fact that OPN is important in the response of GBM to radiotherapy. The in vitro results converge to the fact that OPN might be implicated in the initiation of the DSBs repair following irradiation. Currently, we would like to investigate this hypothesis in vivo but also to check the effect of OPN depletion combined to radiotherapy on the survival of mice in an orthotopic xenograft model. [less ▲]

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See detailL'asporine : une nouvelle defense naturelle contre le cancer du sein.
Blomme, Arnaud; Cusumano, Pino; Peulen, Olivier ULg et al

in Medecine Sciences : M/S (2016), 32(11), 1019-1022

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See detailEXPEL: A Novel Non-Destructive Method for Mining Soluble Tumor Biomarkers
Costanza, B; Blomme, A; Bellahcene, Akeila ULg et al

in Acta Gastro-Enterologica Belgica (2016), 79(1), 11

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See detailMyoferlin plays a key role in VEGFA secretion and impacts tumor-associated angiogenesis in human pancreas cancer
Fahmy, Karim ULg; Gonzalez, Arnaud ULg; Arafa, Mohammad et al

in International Journal of Cancer = Journal International du Cancer (2016), 138

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers with no satisfactory treatment to date. Recent studies have identified myoferlin, a ferlin family member, in human pancreas ... [more ▼]

Pancreatic ductal adenocarcinoma is one of the most deadly forms of cancers with no satisfactory treatment to date. Recent studies have identified myoferlin, a ferlin family member, in human pancreas adenocarcinoma where its expression was associated to a bad prognosis. However, the function of myoferlin in pancreas adenocarcinoma has not been reported. In other cell types, myoferlin is involved in several key plasma membrane processes such as fusion, repair, endocytosis and tyrosine kinase receptor activity. In this study, we showed that myoferlin silencing in BxPC-3 human pancreatic cancer cells resulted in the inhibition of cell proliferation in vitro and in a significant reduction of the tumor volume in chick chorioallantoic membrane assay. In addition to be smaller, the tumors formed by the myoferlin-silenced cells showed a marked absence of functional blood vessels. We further demonstrated that this effect was due, at least in part, to an inhibition of VEGFA secretion by BxPC-3 myoferlin-silenced cells. Using immunofluorescence and electron microscopy, we linked the decreased VEGFA secretion to an impairment of VEGFA exocytosis. The clinical relevance of our results was further strengthened by a significant correlation between myoferlin expression in a series of human pancreatic malignant lesions and their angiogenic status evaluated by the determination of the blood vessel density. [less ▲]

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See detailHDAC7 inhibition resets STAT3 tumorigenic activity in human glioblastoma independently of EGFR and PTEN: new opportunities for selected targeted therapies
Peixoto, Paul; Blomme, Arnaud; Costanza, Brunella ULg et al

in Oncogene (2016)

To date, the mutational status of EGFR and PTEN has been shown as relevant for favoring pro- or anti-tumor functions of STAT3 in human glioblastoma multiforme (GBM). We have screened genomic data from 154 ... [more ▼]

To date, the mutational status of EGFR and PTEN has been shown as relevant for favoring pro- or anti-tumor functions of STAT3 in human glioblastoma multiforme (GBM). We have screened genomic data from 154 patients and have identified a strong positive correlation between STAT3 and HDAC7 expression. In the current work we show the existence of a subpopulation of patients overexpressing HDAC7 and STAT3 that has particularly poor clinical outcome. Surprisingly, the somatic mutation rate of both STAT3 and HDAC7 was insignificant in GBM comparing with EGFR, PTEN or TP53. Depletion of HDAC7 in a range of GBM cells induced the expression of tyrosine kinase JAK1 and the tumor suppressor AKAP12. Both proteins synergistically sustained the activity of STAT3 by inducing its phosphorylation (JAK1) and protein expression (AKAP12). In absence of HDAC7, activated STAT3 was responsible for significant imbalance of secreted pro-/anti-angiogenic factors. This inhibited the migration and sprouting of endothelial cells in paracrine fashion in vitro as well as angiogenesis in vivo. In a murine model of GBM, induced HDAC7-silencing decreased the tumor burden by threefold. The current data show for the first time that silencing HDAC7 can reset the tumor suppressor activity of STAT3, independently of the EGFR/PTEN/TP53 background of the GBM. This effect could be exploited to overcome tumor heterogeneity and provide a new rationale behind the development of specific HDAC7 inhibitors for clinical use. [less ▲]

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See detailPegylated Polyplexes Based On HDAC5 siRNA And Aliphatic Polycarbonate Polymers For An Anticancer Therapy
Frère, Antoine ULg; Baroni, Alexandra; Peulen, Olivier ULg et al

Poster (2015, November 23)

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See detailOsteopontin as a new target in glioblastoma progression and resistance to radiotherapy
Henry, Aurélie ULg; Bellahcene, Akeila ULg; Castronovo, Vincenzo ULg et al

Conference (2015, September 10)

Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments ... [more ▼]

Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments include maximal surgical resection, radiotherapy and concomitant or adjuvant chemotherapy with Temozolomide (TMZ). However, the prognosis of adult patients with GBM remains poor and the survival outcome after treatment does not exceed 15 months. Glioblastoma-composing cells have developed many strategies to counteract these current therapies. Among the wide hallmarks acquired to survive, osteopontin (OPN) ranks correlates with lower overall and disease-free/relapse-free survival in all tumors combined, as well in brain cancer. OPN expression is largely considered as a molecular cancer marker associated with poor prognosis for patients with cancer. Our preliminary works (Lamour V and Henry A, IJC 2015) have demonstrated the role of OPN in the tumorigenicity of glioblastoma cells and its importance in the maintenance of the stem charachters. Within the continuance of this work, our recent studies focused on the potential role of OPN in the resistance of glioblastoma cells to radiotherapy and its implication in the initiation of Double Strand Breaks (DSBs) repair mechanism. In this context, U251-MG and U87-MG cells were used to assess the role of OPN in the initiation of the DSBs repair mechanism after an exposure to gamma-irradiation (γ–IR). The transient transfection of both cell lines with siRNA directed against OPN shown a lower induction of γ–H2AX compared to control (irrelevant siRNA). The survival of U251-OPN depleted cells was also affected after an exposure to γ–IR (based on clonogenic assays). However, the sole depletion of OPN in U87 cells affected their survival (independently of the γ–IR). To prove that the secreted form of OPN is necessary to survive after γ–IR, conditionned medium of U87-shSCR clones (rich in OPN) was used to treat U87shOPN clones before an exposure to γ–IR. By immunofluorescence, we observed that the γ–H2AX staining was higher in U87 shOPN clones than when treated with their own conditionned medium (poor in OPN). Currently, we are investigating the in vivo implication of OPN in the initiation of DSBs repair mechanism after an exposure of mice to γ–IR (whole brain exposure). For this purpose, IPTG-inducible U87 shRNA clones (SCR and OPN) have been generated and validated for an orthotopic xenograft model in NOD-SCID mice. The survival after a radiotherapy of 10 Gy (2Gy per day for 5 days) will be assessed in OPN-positive and –negative tumor-bearing mice. Taken together, these datas suggest that OPN could represent an important pronostic factor for patient response to radiotherapy in the context of GBM. [less ▲]

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See detailPolyplex Based on Polycarbonate Polymers for an Efficient Delivery of HDAC5 and HDAC7 siRNA
Frère, Antoine ULg; Tempelaar, Sarah; Peulen, Olivier ULg et al

Poster (2015, June 02)

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