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.

Ethoxyfagaronine, a synthetic analogue of fagaronine that inhibits vascular endothelial growth factor-1, as a new anti-angiogeneic agent.

Angiogenesis plays a pivotal role in tumorigenesis and also contributes to the pathogenesis of hematologic malignancies. A number of plant compounds have shown efficacy in preclinical and clinical studies and some of them possess an anti-angiogenic activity. Our present findings report anti-angiogenic activities of ethoxyfagaronine (etxfag), a synthetic derivative of fagaronine. Once determined the non-cytotoxic concentration of etxfag, we showed that the drug inhibits VEGF-induced angiogenesis in a Matrigel™ plug assay and suppresses ex vivo sprouting from VEGF-treated aortic rings. Each feature leading to neovascularization was then investigated and results demonstrate that etxfag prevents VEGF-induced migration and tube formation in human umbilical vein endothelial cells (HUVEC). Moreover, etxfag also suppresses VEGF-induced VEGFR-2 phosphorylation and inhibits FAK phosphorylation at Y-861 as well as focal adhesion complex turnover. Beside these effects, etxfag modifies MT1-MMP localization at the endothelial cell membrane. Finally, immunoprecipitation assay revealed that etxfag decreases VEGF binding to VEGFR-2. As we previously reported that etxfag is able to prevent leukemic cell invasiveness and adhesion to fibronectin, all together our data collectively support the anti-angiogenic activities of etxfag which could represent an additional approach to current anti-cancer therapies.

The anti-invasive activity of synthetic alkaloid ethoxyfagaronine on L1210 leukemia cells is mediated by down-regulation of plasminogen activators and MT1-MMP expression and activity.

Quaternary benzo[c]phenanthridines such as fagaronine are natural substances which have been reported to exhibit anticancer and anti-leukemic properties. However, the therapeutic use of these molecules is limited due to the high dose required to exhibit anti-tumor activity and subsequent toxicity. In this study, we describe the therapeutic potential of a new derivative of fagaronine, Ethoxyfagaronine (N-methyl-12-ethoxy-2hydroxy-3, 8, 9-trimethoxybenzo[c]-phenanthridiniumchlorhydrate) as an anti-leukemic agent. Cytotoxic activity and cell growth inhibition of Ethoxyfagaronine (Etxfag) was tested on murine L1210 leukemia cells using trypan blue assay and MTT assay. At the concentration of 10(-7) M, Etxfag induced less than 10% of cell death. Etxfag (10(-7) M) was tested on L1210 cell invasiveness using matrigel™ precoated transwell chambers and efficiently reduces the invasive potential of L1210 cells by more than 50% as compared with untreated cells. Western blot and immunofluorescence experiments showed that Etxfag decreased both MT1-MMP expression and activation at the cell surface, decreased plasmin activity by down-regulating u-PAR and uPA expression at the cell surface and increasing PAI-1 secretion in conditioned media. The set of our findings underscore the therapeutic potential of ethoxyfagaronine as a new potential anticancer agent able to prevent leukemic cell dissemination.

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

We previously demonstrated that the CNYYSNS peptide derived from tumstatin inhibited in vivo tumor progression. The YSNS motif formed a beta-turn crucial for biological activity. More recently, a YSNSG cyclopeptide with a constrained beta-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 beta1-integrin distribution in endothelial cell lamellipodia, induced a strong decrease in the phosphorylated focal adhesion kinase (p125(FAK)), 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.