Biological activities, mechanisms of action and biomedical prospect of the antitumor ether phospholipid ET-18-OCH3 (edelfosine), a proapoptotic agent in tumor cells

The antitumor ether lipid ET-18-OCH3 (edelfosine) is the type of a new class of antineoplastic agents, synthetic analogues of lysophosphatidylcholine, that shows a high metabolic stability, does not interact with DNA and shows a selective apoptotic response in tumor cells, sparing normal cells. Unlike currently used antitumor drugs, ET-18-OCH3 does not act directly on the formation and function of the replication machinery, and thereby its effects are independent of the proliferative state of target cells. Because of its capacity to modulate cellular regulatory and signaling events, including those failing in cancer cells, like defective apoptosis, ET-18-OCH3, beyond its putative clinical importance, is an interesting model compound for the development of more selective drugs for cancer therapy. Although ET-18-OCḢ 3 enhances host defense mechanisms against tumors, its major antitumor action lies in a direct effect on cancer cells, inhibiting phosphatiḋylcholine bioṡynthesis and inducing apoptosis in tumor cells. Recent progress has allowed unravelinġ the molecular mechanism underlying the apoptotic action of ET-18-OCH3, leading to the notion that ET-18-OCH3 is selectively incorporated into tumor cells and induces cell death by intracellular activation of the cell death receptor Fas/CD95. This intracellular Fas/CD95 activation is a novel mechanism of action for an antitumor drug and represents a new way to target tumor cells in cancer chemotherapy that can be of interest as a new framework in designing novel antitumor drugs. ET-18-OCH3 and some analogues are pleiotropic agents that affect additional biomedical important diseases, including parasitic and autoimmune diseases, suggesting new therapeutic indications for these compounds.The work of the authors was supported by grant CDTI 97-0355 from INKEYSA and Ministerio de Industria y Energía of Spain, and grants 1FD97-2018-C02-01 and 1FD97-0622 from the European Commission and Comisión Interministerial de Ciencia y Tecnología of Spain.Peer Reviewe

Involvement of raft aggregates enriched in Fas/CD95 death-inducing signaling complex in the antileukemic action of edelfosine in Jurkat cells

[Background]: Recent evidence suggests that co-clustering of Fas/CD95 death receptor and lipid rafts plays a major role in death receptor-mediated apoptosis. [Methodology/Principal Findings]: By a combination of genetic, biochemical, and ultrastructural approaches, we provide here compelling evidence for the involvement of lipid raft aggregates containing recruited Fas/CD95 death receptor, Fas-associated death domain-containing protein (FADD), and procaspase-8 in the induction of apoptosis in human T-cell leukemia Jurkat cells by the antitumor drug edelfosine, the prototype compound of a promising family of synthetic antitumor lipids named as synthetic alkyl-lysophospholipid analogues. Co-immunoprecipitation assays revealed that edelfosine induced the generation of the so-called death-inducing signaling complex (DISC), made up of Fas/CD95, FADD, and procaspase-8, in lipid rafts. Electron microscopy analyses allowed to visualize the formation of raft clusters and their co-localization with DISC components Fas/CD95, FADD, and procaspase-8 following edelfosine treatment of Jurkat cells. Silencing of Fas/CD95 by RNA interference, transfection with a FADD dominant-negative mutant that blocks Fas/CD95 signaling, and specific inhibition of caspase-8 prevented the apoptotic response triggered by edelfosine, hence demonstrating the functional role of DISC in drug-induced apoptosis. By using radioactive labeled edelfosine and a fluorescent analogue, we found that edelfosine accumulated in lipid rafts, forming edelfosine-rich membrane raft clusters in Jurkat leukemic T-cells. Disruption of these membrane raft domains abrogated drug uptake and drug-induced DISC assembly and apoptosis. Thus, edelfosine uptake into lipid rafts was critical for the onset of both co-aggregation of DISC in membrane rafts and subsequent apoptotic cell death. [Conclusions/Significance]: This work shows the involvement of DISC clusters in lipid raft aggregates as a supramolecular and physical entity responsible for the induction of apoptosis in leukemic cells by the antitumor drug edelfosine. Our data set a novel framework and paradigm in leukemia therapy, as well as in death receptor-mediated apoptosis.This work was supported by grants from Fondo de Investigacion Sanitaria and European Commission (FIS-FEDER 06/0813), Ministerio de Ciencia e Innovacion of Spain (SAF2008-02251 and RD06/0020/1037 - Red Tematica de Investigacion Cooperativa en Cancer, Instituto de Salud Carlos III), Junta de Castilla y Leon (CSI01A08, SAN673/SA32/08, and GR15 - Experimental Therapeutics and Translational Oncology Program), Fundacion “la Caixa” (BM05-30-0), and Fundacion de Investigacion Medica Mutua Madrilena (FMM). CG is supported by the Ramon y Cajal Program from the Ministerio de Ciencia e Innovacion of Spain.Peer Reviewe

Involvement of Raft Aggregates Enriched in Fas/CD95 Death-Inducing Signaling Complex in the Antileukemic Action of Edelfosine in Jurkat Cells

BACKGROUND: Recent evidence suggests that co-clustering of Fas/CD95 death receptor and lipid rafts plays a major role in death receptor-mediated apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: By a combination of genetic, biochemical, and ultrastructural approaches, we provide here compelling evidence for the involvement of lipid raft aggregates containing recruited Fas/CD95 death receptor, Fas-associated death domain-containing protein (FADD), and procaspase-8 in the induction of apoptosis in human T-cell leukemia Jurkat cells by the antitumor drug edelfosine, the prototype compound of a promising family of synthetic antitumor lipids named as synthetic alkyl-lysophospholipid analogues. Co-immunoprecipitation assays revealed that edelfosine induced the generation of the so-called death-inducing signaling complex (DISC), made up of Fas/CD95, FADD, and procaspase-8, in lipid rafts. Electron microscopy analyses allowed to visualize the formation of raft clusters and their co-localization with DISC components Fas/CD95, FADD, and procaspase-8 following edelfosine treatment of Jurkat cells. Silencing of Fas/CD95 by RNA interference, transfection with a FADD dominant-negative mutant that blocks Fas/CD95 signaling, and specific inhibition of caspase-8 prevented the apoptotic response triggered by edelfosine, hence demonstrating the functional role of DISC in drug-induced apoptosis. By using radioactive labeled edelfosine and a fluorescent analogue, we found that edelfosine accumulated in lipid rafts, forming edelfosine-rich membrane raft clusters in Jurkat leukemic T-cells. Disruption of these membrane raft domains abrogated drug uptake and drug-induced DISC assembly and apoptosis. Thus, edelfosine uptake into lipid rafts was critical for the onset of both co-aggregation of DISC in membrane rafts and subsequent apoptotic cell death. CONCLUSIONS/SIGNIFICANCE: This work shows the involvement of DISC clusters in lipid raft aggregates as a supramolecular and physical entity responsible for the induction of apoptosis in leukemic cells by the antitumor drug edelfosine. Our data set a novel framework and paradigm in leukemia therapy, as well as in death receptor-mediated apoptosis

Substitution at the indole 3 position yields highly potent indolecombretastatins with reduced susceptibility to MDR resistance

[EN]Resistance to combretastatin A-4 is mediated by metabolic modification of the phenolic hydroxyl and ether groups of the 3-hydroxy-4-methoxyphenyl (B ring). Replacement of the B ring of combretastatin A-4 by a N-methyl-5-indolyl reduces tubulin polymerization inhibition (TPI) and cytotoxicity against human cancer cell lines but cyano, methoxycarbonyl, formyl, and hydroxyiminomethyl substitutions at the indole 3-position restores potent TPI and cytotoxicity against sensitive human cancer cell lines. These highly potent substituted derivatives displayed low nanomolar cytotoxicity against several human cancer cell lines due to tubulin inhibition, as shown by cell cycle analysis, confocal microscopy, and tubulin polymerization inhibitory activity studies and promoted cell killing mediated by caspase-3 activation. Binding at the colchicine site was suggested by molecular modeling studies. Substituted combretastatins displayed higher potencies than the isomeric isocombretastatins and the highest potencies were achieved for the hydroxyiminomethyl (21) and cyano (23) groups, with TPI values in the submicromolar range and cytotoxicities in the subnanomolar range. Dose-response and time-course studies showed that drug concentrations as low as 1 nM (23) or 10 nM (21) led to a complete G2/M cell cycle arrest after 15 h treatment followed by a high apoptosis-like cell § These authors contributed equally to this work. 3 response after 48-72 h treatment. The P-glycoprotein and calcium antagonist verapamil increased 21 and 23 cytotoxicity to IC50 values of 10-10 M, and highly potentiated the cytotoxic activity in 100-fold of the CHO derivative (17), in A549 human non-small cell lung cancer cells. The differences in cytotoxic potency observed between the highly potent cyano (23) and hydroxyiminomethyl (21) groups and other substituents with similar TPI values (17) were very much reduced upon co-treatment with verapamil. A 3,4,5-trimethoxyphenyl ring always afforded more potent derivatives than a 2,3,4-trimethoxyphenyl ring

Involvement of lipid rafts in the localization and dysfunction effect of the antitumor ether phospholipid edelfosine in mitochondria

This work is licensed under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License.-- et al.Lipid rafts and mitochondria are promising targets in cancer therapy. The synthetic antitumor alkyl-lysophospholipid analog edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) has been reported to target lipid rafts. Here, we have found that edelfosine induced loss of mitochondrial membrane potential and apoptosis in human cervical carcinoma HeLa cells, both responses being abrogated by Bcl-xL overexpression. We synthesized a number of new fluorescent edelfosine analogs, which preserved the proapoptotic activity of the parent drug, and colocalized with mitochondria in HeLa cells. Edelfosine induced swelling in isolated mitochondria, indicating an increase in mitochondrial membrane permeability. This mitochondrial swelling was independent of reactive oxygen species generation. A structurally related inactive analog was unable to promote mitochondrial swelling, highlighting the importance of edelfosine molecular structure in its effect on mitochondria. Raft disruption inhibited mitochondrial localization of the drug in cells and edelfosine-induced swelling in isolated mitochondria. Edelfosine promoted a redistribution of lipid rafts from the plasma membrane to mitochondria, suggesting a raft-mediated link between plasma membrane and mitochondria. Our data suggest that direct interaction of edelfosine with mitochondria eventually leads to mitochondrial dysfunction and apoptosis. These observations unveil a new framework in cancer chemotherapy that involves a link between lipid rafts and mitochondria in the mechanism of action of an antitumor drug, thus opening new avenues for cancer treatment.This work was supported by the Spanish Ministerio de Ciencia e Innovación (SAF2008-02251, BQU2003-4413 and RD06/0020/1037 from Red Temática de Investigación Cooperativa en Cáncer, Instituto de Salud Carlos III, cofunded by the Fondo Europeo de Desarrollo Regional of the European Union), Fondo de Investigación Sanitaria and European Commission (FIS-FEDER 06/0813, 08/1434, PS09/01915), European Community's Seventh Framework Programme FP7-2007-2013 (grant HEALTH-F2-2011-256986), Junta de Castilla y León (CSI052A11-2, GR15-Experimental Therapeutics and Translational Oncology Program, Biomedicine Project 2009 and Biomedicine Project 2010-2011), Fundación para la Investigación Sanitaria en Castilla-La Mancha (FISCAM, PI-2006/10) and Junta de Comunidades de Castilla-La Mancha (I1I09-0163-4002). CG is supported by the Ramón y Cajal Program from the Spanish Ministerio de Ciencia e Innovación. MF is recipient of a postdoctoral fellowship from Fondo de Investigación Sanitaria. VH is recipient of a predoctoral fellowship from the Spanish Ministerio de Ciencia e Innovación.Peer reviewe

Intracellular Triggering of Fas Aggregation and Recruitment of Apoptotic Molecules into Fas-enriched Rafts in Selective Tumor Cell Apoptosis

We have discovered a new and specific cell-killing mechanism mediated by the selective uptake of the antitumor drug 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3, Edelfosine) into lipid rafts of tumor cells, followed by its coaggregation with Fas death receptor (also known as APO-1 or CD95) and recruitment of apoptotic molecules into Fas-enriched rafts. Drug sensitivity was dependent on drug uptake and Fas expression, regardless of the presence of other major death receptors, such as tumor necrosis factor (TNF) receptor 1 or TNF-related apoptosis-inducing ligand R2/DR5 in the target cell. Drug microinjection experiments in Fas-deficient and Fas-transfected cells unable to incorporate exogenous ET-18-OCH3 demonstrated that Fas was intracellularly activated. Partial deletion of the Fas intracellular domain prevented apoptosis. Unlike normal lymphocytes, leukemic T cells incorporated ET-18-OCH3 into rafts coaggregating with Fas and underwent apoptosis. Fas-associated death domain protein, procaspase-8, procaspase-10, c-Jun amino-terminal kinase, and Bid were recruited into rafts, linking Fas and mitochondrial signaling routes. Clustering of rafts was necessary but not sufficient for ET-18-OCH3–mediated cell death, with Fas being required as the apoptosis trigger. ET-18-OCH3–mediated apoptosis did not require sphingomyelinase activation. Normal cells, including human and rat hepatocytes, did not incorporate ET-18-OCH3 and were spared. This mechanism represents the first selective activation of Fas in tumor cells. Our data set a framework for the development of more targeted therapies leading to intracellular Fas activation and recruitment of downstream signaling molecules into Fas-enriched rafts

Suppression of metastatic organ colonization and antiangiogenic activity of the orally bioavailable lipid raft-targeted alkylphospholipid edelfosine

Metastasis is the leading cause of cancer mortality. Metastatic cancer is notoriously difficult to treat, and it accounts for the majority of cancer -related deaths. The ether lipid edelfosine is the prototype of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs, and its antitumor activity involves lipid raft reorganization. In this study, we examined the effect of edelfosine on metastatic colonization and angiogenesis. Using non-invasive bioluminescence imaging and histological examination, we found that oral administration of edelfosine in nude mice significantly inhibited the lung and brain colonization of luciferaseexpressing 435-Lung-eGFP-CMV/Luc metastatic cells, resulting in prolonged survival. In metastatic 435 -Lung and MDA-MB-231 breast cancer cells, we found that edelfosine also inhibited cell adhesion to collagen -I and laminin-I substrates, cell migration in chemotaxis and wound -healing assays, as well as cancer cell invasion. In 435 -Lung and other MDA-MB-435-derived sublines with different organotropism, edelfosine induced G2/M cell cycle accumulation and apoptosis in a concentration- and time -dependent manner. Edelfosine also inhibited in vitro angiogenesis in human and mouse endothelial cell tube formation assays. The antimetastatic properties were specific to cancer cells, as edelfosine had no effects on viability in non -cancerous cells. Edelfosine accumulated in membrane rafts and endoplasmic reticulum of cancer cells, and membrane raft -located CD44 was downregulated upon drug treatment. Taken together, this study highlights the potential of edelfosine as an attractive drug to prevent metastatic growth and organ colonization in cancer therapy. The raft -targeted drug edelfosine displays a potent activity against metastatic organ colonization and angiogenesis, two major hallmarks of tumor malignancy

Identification of new FK866 analogues with potent anticancer activity against pancreatic cancer

11 p.- 2 fig.-4 tab.-8 schem.-1 graph. abst.Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases for which chemotherapy has not been very successful yet. FK866 ((E)-N-(4-(1-benzoylpiperidin-4-yl)butyl)-3-(pyridin-3-yl)acrylamide) is a well-known NAMPT (nicotinamide phosphoribosyltransferase) inhibitor with anti-cancer activities, but it failed in phase II clinical trials. We found that FK866 shows anti-proliferative activity in three PDAC cell lines, as well as in Jurkat T-cell leukemia cells. More than 50 FK866 analogues were synthesized that introduce substituents on the phenyl ring of the piperidine benzamide group of FK866 and exchange its buta-1,4-diyl tether for 1-oxyprop-3-yl, (E)-but-2-en-1,4-diyl and 2- and 3-carbon tethers. The pyridin-3-yl moiety of FK866 was exchanged for chlorinated and fluorinated analogues and for pyrazin-2-yl and pyridazin-4-yl groups. Several compounds showed low nanomolar or sub-nanomolar cell growth inhibitory activity. Our best cell anti-proliferative compounds were the 2,4,6-trimethoxybenzamide analogue of FK866 ((E)-N-(4-(1-(2,4,6-trimethoxybenzoyl)piperidin-4-yl)butyl)-3-(pyridin-3-yl)acrylamide) (9), the 2,6-dimethoxybenzamide (8) and 2-methoxybenzamide (4), which exhibited an IC50 of 0.16 nM, 0.004 nM and 0.08 nM toward PDAC cells, respectively.The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7-2007-2013] under grant agreement no. 256986 (PANACREAS), from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 813284 (INTEGRATA), by the Spanish Ministry of Science, Innovation, and Universities (SAF2017-89672-R) and by the Associazione Italiana per la Ricerca sul Cancro (AIRC), IG#22098.Peer reviewe

Innovaciones y mejoras en el proyecto tutoría entre compañeros. Curso 2015-2016

Memoria ID-0137. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2015-2016