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

Targeting focal adhesion assembly by ethoxyfagaronine prevents lymphoblastic cell adhesion to fibronectin

Background: Leukemic cell adhesion to proteins of the bone marrow microenvironment provides signals which control morphology, motility and cell survival. We described herein the ability of ethoxyfagaronine (etxfag), a soluble synthetic derivative of fagaronine, to prevent leukemic cell adhesion to fibronectin peptide (FN/V). Methods: Phosphorylation of fak and pyk2 were evaluated by immunoblotting. Labelled proteins were localized by confocal microscopy. PI 3-kinase activity was evaluated by in vitro kinase assay. Results: Subtoxic concentration of etxfag reduced L1210 cell adhesion to FN/V dependently of β1 integrin engagement. Etxfag impaired FN-dependent formation of β1 clustering without modifying β1 expression at the cell membrane. This was accompanied by a decrease of focal adhesion number, a diminution of fak and pyk2 phosphorylation at Tyr-576, Tyr-861 and Tyr-579, respectively leading to their dissociations from β1 integrin and inhibition of PI 3-kinase activity. Etxfag also induced a cell retraction accompanied by a redistribution of phosphorylated fak and pyk2 in the perinuclear region and lipid raft relocalization. Conclusion: Through its anti-adhesive potential, etxfag, combined with conventional cytotoxic drugs could be potentially designed as a new anti-leukemic drug

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

Computational, Structural, and Mechanistic Analysis of the Electrochemically Driven Pirouetting Motion of a Copper Rotaxane

A mechanism for the electrochemically driven reorganization of a model copper [2]pseudorotaxane is proposed on the basis of density functional theory computations and validated by comparing to experimental results. We investigate in detail the ligand reorganization around the Cu ion from a 4 to 5 coordination number that follows the conversion of the oxidation state from +1 to +2. It is found that for both the oxidation and the reduction processes the rearrangement proceeds in a concerted fashion via a single transition state. Energy paths involving stable decoordinated-coordinated intermediates are computed to be higher in energy. The cyclic voltammogram simulated using the computed transition theory state rate constants in solvent medium is in good agreement with the experimental voltammogram. Further, we report on the computed concentration change of stable (Cu-4(+), Cu-5(2+)) and metastable species (Cu-4(2+), Cu-5(+)) during single cyclic voltammetry (CV) cycle as a function of the applied voltage or time (the subscripts 4 and 5 refer to the coordination number of the copper center)