Evaluation of anti-leukemic potential a benzo(c)phenanthridine, the ethoxyfagaronine

Les leucémies aigües se caractérisent par une prolifération incontrôlée et par l'augmentation accrue de cellules hématopoïétiques immatures dans la circulation sanguine conduisant à l'infiltration de nombreux organes. Un certain nombre de mécanismes tels que la protéolyse matricielle, l'adhérence cellulaire et l'angiogénèse participent à ce processus d'infiltration extramédullaire et favorisent l'apparition de rechute suite au traitement chimio-thérapeutique. Notre projet s'intéresse à l'éthoxyfagaronine, une benzo(c)phénantridine dérivée de la fagaronine. Au cours de notre étude, nous avons mis en évidence la capacité de l'Etxfag à réduire le potentiel invasif des cellules L1210 impliquant une diminution de l'expression de la MT-MMP à la membrane plasmique ainsi qu'une inhibition du système activateur du plasminogène. Nous mettons également en évidence la capacité de l'Etxfag à diminuer l'adhérence des cellules L1210 au peptide de fibronectine WQPPRARI. Cette diminution implique une déstructuration des radeaux lipidiques empêchant le clustering des intégrines beta1 et leur interaction avec le peptide de fibronectine. Nous montrons également la diminution de l'activation des voies de signalisation dépendantes des intégrines telles que FAK, PYK2 et la PI3-kinase. Notre étude a également porté sur les effets anti-angiogéniques de l'Extfag. Nous montrons la capacité de l'Extfag à réduire l'angiogénèse par l'utilisation de modèle in vitro, ex vivo et in vivo. Cet effet anti-angiogénique semble être lié à une altération des propriétés migratoires des cellules endothéliales. L'ensemble de ces résultats souligne le potentiel anti-leucémique de l'Extfag qui pourrait représenter un nouvel agent chimio-thérapeutique capable de prévenir la dissémination des cellules leucémiques.Acute leukemias are characterized by uncontrolled proliferation and increased immature hematopoietic cells in the bloodstream leading to the infiltration of many organs. A number of mechanisms such as matrix proteolysis, cell adhesion and angiogenesis are involved in extramedullary infiltration process and promote the appearance of relapse after chemotherapeutic treatment. Our project focuses on the ethoxyfagaronine (Extfag), a benzo(c)phenanthridine derivative of fagaronine. In our study, we demonstrated the ability of the Extfag to reduce the invasive potential of L1210 cells by decreasing MT1-MMP expression to the plasma membrane and by inhibiting the plasminogen activator system. We also demonstrated the ability of Extfag to reduce the adhesion of L1210 cells to fibronectin peptide WQPPRARI. This reduction implies a disorganization of lipid rafts preventing clustering of beta1 integrins and their interaction with fibronectin peptide. We also have shown a decrease of integrin-dependent signaling pathways activation such as FAK, PYK2 and PI3-kinase. We have also studied the anti-angiogenic effects of Extfag. We have shown the ability of the Extfag to reduce angiogenesis by using in vitro, ex vivo and in vivo model. This antiangiogenic effect seems to be related to altered migratory properties of endothelial cells. Taken together, these results highlight the anti-leukemic potential of Extfag which could represent a new chemotherapeutic agent capable of preventing leukemic cells dissemination

Evaluation du potentiel anti-leucémique d'une benzo(c)phénanthridine, l'Ethoxyfagaronine

Les leucémies aigües se caractérisent par une prolifération incontrôlée et par l'augmentation accrue de cellules hématopoïétiques immatures dans la circulation sanguine conduisant à l'infiltration de nombreux organes. Un certain nombre de mécanismes tels que la protéolyse matricielle, l'adhérence cellulaire et l'angiogénèse participent à ce processus d'infiltration extramédullaire et favorisent l'apparition de rechute suite au traitement chimio-thérapeutique. Notre projet s'intéresse à l'éthoxyfagaronine, une benzo(c)phénantridine dérivée de la fagaronine. Au cours de notre étude, nous avons mis en évidence la capacité de l'Etxfag à réduire le potentiel invasif des cellules L1210 impliquant une diminution de l'expression de la MT-MMP à la membrane plasmique ainsi qu'une inhibition du système activateur du plasminogène. Nous mettons également en évidence la capacité de l'Etxfag à diminuer l'adhérence des cellules L1210 au peptide de fibronectine WQPPRARI. Cette diminution implique une déstructuration des radeaux lipidiques empêchant le clustering des intégrines beta1 et leur interaction avec le peptide de fibronectine. Nous montrons également la diminution de l'activation des voies de signalisation dépendantes des intégrines telles que FAK, PYK2 et la PI3-kinase. Notre étude a également porté sur les effets anti-angiogéniques de l'Extfag. Nous montrons la capacité de l'Extfag à réduire l'angiogénèse par l'utilisation de modèle in vitro, ex vivo et in vivo. Cet effet anti-angiogénique semble être lié à une altération des propriétés migratoires des cellules endothéliales. L'ensemble de ces résultats souligne le potentiel anti-leucémique de l'Extfag qui pourrait représenter un nouvel agent chimio-thérapeutique capable de prévenir la dissémination des cellules leucémiques.Acute leukemias are characterized by uncontrolled proliferation and increased immature hematopoietic cells in the bloodstream leading to the infiltration of many organs. A number of mechanisms such as matrix proteolysis, cell adhesion and angiogenesis are involved in extramedullary infiltration process and promote the appearance of relapse after chemotherapeutic treatment. Our project focuses on the ethoxyfagaronine (Extfag), a benzo(c)phenanthridine derivative of fagaronine. In our study, we demonstrated the ability of the Extfag to reduce the invasive potential of L1210 cells by decreasing MT1-MMP expression to the plasma membrane and by inhibiting the plasminogen activator system. We also demonstrated the ability of Extfag to reduce the adhesion of L1210 cells to fibronectin peptide WQPPRARI. This reduction implies a disorganization of lipid rafts preventing clustering of beta1 integrins and their interaction with fibronectin peptide. We also have shown a decrease of integrin-dependent signaling pathways activation such as FAK, PYK2 and PI3-kinase. We have also studied the anti-angiogenic effects of Extfag. We have shown the ability of the Extfag to reduce angiogenesis by using in vitro, ex vivo and in vivo model. This antiangiogenic effect seems to be related to altered migratory properties of endothelial cells. Taken together, these results highlight the anti-leukemic potential of Extfag which could represent a new chemotherapeutic agent capable of preventing leukemic cells dissemination.REIMS-SCD-Bib. electronique (514549901) / SudocSudocFranceF

The YSNSG cyclopeptide derived from tumstatin inhibits tumor angiogenesis by down-regulating endothelial cell migration.

International audienceWe previously demonstrated that the CNYYSNS peptide derived from tumstatin inhibited in vivo tumor progression. The YSNS motif formed a β-turn crucial for biological activity. More recently, a YSNSG cyclopeptide with a constrained β-turn on the YSNS residues was designed. Intraperitoneal administration of the YSNSG cyclopeptide inhibited in vivo melanoma progression more efficiently than the native linear peptide. In the present article, we showed that the YSNSG cyclopeptide also triggered an inhibition of in vivo tumor neovascularization and we further analyzed its in vitroantiangiogenic effect. The YSNSG cyclopeptide did not alter endothelial cell proliferation but inhibited cell migration by 83% in an in vitro wound healing model. The inhibition was mediated by a decrease in active MT1-MMP at the migration front as well as a decrease in u-PA and u-PAR expression. The cyclopeptide also altered β1-integrin distribution in endothelial cell lamellipodia, induced a strong decrease in the phosphorylated focal adhesion kinase (p125FAK), disorganized F-actin stress fibers and decreased the number of lamellipodia, resulting in a non migratory phenotype. Our results confirm the YSNSG cyclopeptide as a potent antitumor agent, through both the inhibition of invasive properties of tumor cells and the antiangiogenic activity

X-linked primary immunodeficiency associated with hemizygous mutations in the moesin (MSN) gene

BACKGROUND: We investigated 7 male patients (from 5 different families) presenting with profound lymphopenia, hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a poor immune response to vaccine antigens, and increased susceptibility to bacterial and varicella zoster virus infections. OBJECTIVE: We sought to characterize the genetic defect involved in a new form of X-linked immunodeficiency. METHODS: We performed genetic analyses and an exhaustive phenotypic and functional characterization of the lymphocyte compartment. RESULTS: We observed hemizygous mutations in the moesin (MSN) gene (located on the X chromosome and coding for MSN) in all 7 patients. Six of the latter had the same missense mutation, which led to an amino acid substitution (R171W) in the MSN four-point-one, ezrin, radixin, moesin domain. The seventh patient had a nonsense mutation leading to a premature stop codon mutation (R533X). The naive T-cell counts were particularly low for age, and most CD8(+) T cells expressed the senescence marker CD57. This phenotype was associated with impaired T-cell proliferation, which was rescued by expression of wild-type MSN. MSN-deficient T cells also displayed poor chemokine receptor expression, increased adhesion molecule expression, and altered migration and adhesion capacities. CONCLUSION: Our observations establish a causal link between an ezrin-radixin-moesin protein mutation and a primary immunodeficiency that could be referred to as X-linked moesin-associated immunodeficiency