Jose Luis Abad

Publications (8)40.48 Total impact

• Article: A Straightforward Access to Spisulosine and 4,5-Dehydrospisulosine Stereoisomers. Probes for profiling ceramide synthase activities in intact cells.

  Jose Luis Abad, Ingrid Nieves, Pedro Rayo, Josefina Casas, Gemma Fabrias, Antonio Delgado
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  ABSTRACT: A stereoselective synthesis of spisulosine (ES285) and 4,5-dehydrospisulosine stereoisomers is described. Hydrozirconation of 1-pentadecyne with Schwartz reagent, followed by diastereocontrolled addition to L- or D-alaninal afforded the required 2-amino 1,3-diol framework. The resulting sphingoid bases revealed as excellent probes for the profiling of ceramide synthase activity in intact cells. Among the sphingoid bases described in this work, spisulosine (ES285), RBM1-77 and RBM1-73 were the most suitable ones due to their highest acylation rates. These molecules should prove useful to study the role of the different ceramide synthases and the resulting N acyl (dihydro)ceramides in cell fate.
  The Journal of Organic Chemistry 05/2013; · 4.45 Impact Factor
• Article: C6-ceramide and targeted inhibition of acid ceramidase induce synergistic decreases in breast cancer cell growth.

  Margaret Flowers, Gemma Fabriás, Antonio Delgado, Josefina Casas, Jose Luis Abad, Myles C Cabot
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  ABSTRACT: The sphingolipid ceramide is known to play a central role in chemo- and radiation-induced cell death. Acid ceramidase (AC) hydrolyzes ceramide, and thus reduces intracellular levels of this proapoptotic lipid. The role of AC as a putative anticancer target is supported by reports of upregulation in prostate cancer and in some breast tumors. In this study, we determined whether the introduction of an AC inhibitor would enhance the apoptosis-inducing effects of C6-ceramide (C6-cer) in breast cancer cells. Cultured breast cancer cells were treated with DM102 [(2R,3Z)-N-(1-hydroxyoctadec-3-en-2-yl)pivalamide, C6-cer, or the combination. Cell viability and cytotoxic synergy were assessed. Activation of apoptotic pathways, generation of reactive oxygen species, and mitochondrial transmembrane potential were determined. DM102 was a more effective AC inhibitor than N-oleoylethanolamine (NOE) and (1R,2R)-2-N-(tetradecanoylamino)-1-(4'-nitrophenyl)-1,3-propandiol (B-13) in MDA-MB-231, MCF-7, and BT-474 cells. As single agents, C6-cer (IC(50) 5-10 μM) and DM102 (IC(50) 20 μM) were only moderately cytotoxic in MDA-MB-231, MCF-7, and SK-BR-3 cells. Co-administration, however, produced synergistic decreases in viability (combination index <0.5) in all cell lines. Apoptosis was confirmed in MDA-MB-231 cells by detection of caspase 3 cleavage and a >3-fold increase in caspase 3/7 activation, PARP cleavage, and a >70% increase in Annexin-V positive cells. C6-cer/DM102 increased ROS levels 4-fold in MDA-MB-231 cells, shifted the ratio of Bax:Bcl-2 to >9-fold that of control cells, and resulted in mitochondrial membrane depolarization. DM102 also increased the synthesis of (3)H-palmitate-labeled long-chain ceramides by 2-fold when C6-cer was present. These data support the effectiveness of targeting AC in combination with exogenous short-chain ceramide as an anticancer strategy, and warrant continued investigation into the utility of the C6-cer/DM102 drug duo in human breast cancer.
  Breast Cancer Research and Treatment 09/2011; 133(2):447-58. · 4.43 Impact Factor
• Source

  Available from: Santos Mañes

  Article: Dihydrosphingomyelin impairs HIV-1 infection by rigidifying liquid-ordered membrane domains.

  Catarina R Vieira, Jose M Munoz-Olaya, Jesús Sot, Sonia Jiménez-Baranda, Nuria Izquierdo-Useros, Jose Luis Abad, Beatriz Apellániz, Rafael Delgado, Javier Martinez-Picado, Alicia Alonso, Josefina Casas, José L Nieva, Gemma Fabriás, Santos Mañes, Félix M Goñi
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  ABSTRACT: The lateral organization of lipids in cell membranes is thought to regulate numerous cell processes. Most studies focus on the coexistence of two fluid phases, the liquid crystalline (l(d)) and the liquid-ordered (l(o)); the putative presence of gel domains (s(o)) is not usually taken into account. We show that in phospholipid:sphingolipid:cholesterol mixtures, in which sphingomyelin (SM) promoted fluid l(o) domains, dihydrosphingomyelin (DHSM) tended to form rigid domains. Genetic and pharmacological blockade of the dihydroceramide desaturase (Des1), which replaced SM with DHSM in cultured cells, inhibited cell infection by replication-competent and -deficient HIV-1. Increased DHSM levels gave rise to more rigid membranes, resistant to the insertion of the gp41 fusion peptide, thus inhibiting viral-cell membrane fusion. These results clarify the function of dihydrosphingolipids in biological membranes and identify Des1 as a potential target in HIV-1 infection.
  Chemistry & biology 07/2010; 17(7):766-75. · 6.52 Impact Factor
• Source

  Available from: Mitko Subchev

  Article: Sex pheromone biosynthetic pathway for disparlure in the gypsy moth, Lymantria dispar.

  Russell A Jurenka, Mitko Subchev, Jose-Luis Abad, Man-Yeon Choi, Gemma Fabrias
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  ABSTRACT: The pheromone biosynthetic pathway for production of the sex pheromone disparlure, 2-methyl-7R,8S-epoxy-octadecane, was determined for the gypsy moth. Each step in the pathway was followed by using deuterium-labeled compounds that could be identified by using GCMS. This approach provides unequivocal determination of specific reactions in the pathway. It was shown that the alkene precursor, 2-methyl-Z7-octadecene, is most likely made in oenocyte cells associated with abdominal epidermal cells. The pathway begins with valine contributing carbons for chain initiation, including the methyl-branched carbon, followed by chain elongation to 19 carbons. The double bond is introduced with an unusual Delta12 desaturase that utilizes a methyl-branched substrate. The resulting 18-methyl-Z12-nonadecenoate is decarboxylated to the hydrocarbon, 2-methyl-Z7-octadecene. The alkene is then transported to the pheromone gland through the hemolymph, most probably by lipophorin. At the pheromone gland, the alkene is unloaded and transformed into the epoxide disparlure for release into the environment. A chiral HPLC column was used to demonstrate that the (R,S)-stereoisomer of the epoxide, (+)-disparlure is found in pheromone glands.
  Proceedings of the National Academy of Sciences 03/2003; 100(3):809-14. · 9.68 Impact Factor
• Article: Inhibition of programmed cell death impairs in vitro vascular-like structure formation and reduces in vivo angiogenesis.

  Inmaculada Segura, Antonio Serrano, Gonzalo González De Buitrago, Manuel A González, Jose Luis Abad, Cristina Clavería, Lucio Gómez, Antonio Bernad, Carlos Martínez-A, Hans H Riese
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  ABSTRACT: Tissue remodeling during embryonic development and in the adult organism relies on a subtle balance between cell growth and apoptosis. As angiogenesis involves restructuring of preexisting endothelium, we examined the role of apoptosis in new vessel formation. We show that apoptosis occurs before capillary formation but not after vessels have assembled. Using the human umbilical vein endothelial cell (HUVEC) in vitro Matrigel angiogenesis model, we show that vascular-like structure formation requires apoptotic cell death through activation of a caspase-dependent mechanism and mitochondrial cytochrome c release. Vascular-like structure formation was further blocked by caspase inhibitors such as z-VAD or Ac-DEVD-CHO, using HUVEC and human lung microvascular endothelial cells. Overexpression of anti-apoptotic human Bcl-2 or baculovirus p35 genes in HUVEC altered endothelial cell rearrangement during in vitro angiogenesis, causing impaired vessel-like structure formation. Caspase inhibitors blocked VEGF- or bFGF-induced HUVEC angiogenesis on 2- or 3-D collagen gels, respectively, confirming that apoptosis was not the result of nonspecific cell death after seeding on the matrix. In an in vivo angiogenesis assay, caspase inhibitors blocked VEGF-dependent vascular formation at the alignment step, as demonstrated histologically. This evidence indicates that endothelial cell apoptosis may be relevant for precise vascular tissue rearrangement in in vitro and in vivo angiogenesis.
  The FASEB Journal 07/2002; 16(8):833-41. · 5.71 Impact Factor
• Article: Dioxidosqualenes: characterization and activity as inhibitors of 2,3-oxidosqualene-lanosterol cyclase

  Jose Luis Abad, Josefina Casas, Francisco Sanchez-Baeza, Angel Messeguer
  04/2002;
• Article: Internal Oxidosqualenes: Determination of Absolute Configuration and Activity as Inhibitors of Purified Pig Liver Squalene Epoxidase

  Jose-Luis Abad, Josefina Casas, Francisco Sanchez-Baeza, Angel Messeguer
  04/2002;
• Source

  Available from: Santos Mañes

  Article: Segregation of leading-edge and uropod components into specific lipid rafts during T cell polarization

  Concepción Gómez-Moutón, Jose Luis Abad, Emilia Mira, Rosa Ana Lacalle, Eduard Gallardo, Sonia Jiménez-Baranda, Isabel Illa, Antonio Bernad, Santos Mañes, Carlos Martínez-A
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  ABSTRACT: Redistribution of specialized molecules in migrating cells develops asymmetry between two opposite cell poles, the leading edge and the uropod. We show that acquisition of a motile phenotype in T lymphocytes results in the asymmetric redistribution of ganglioside GM3- and GM1-enriched raft domains to the leading edge and to the uropod, respectively. This segregation to each cell pole parallels the specific redistribution of membrane proteins associated to each raft subfraction. Our data suggest that raft partitioning is a major determinant for protein redistribution in polarized T cells, as ectopic expression of raft-associated proteins results in their asymmetric redistribution, whereas non-raft-partitioned mutants of these proteins are distributed homogeneously in the polarized cell membrane. Both acquisition of a migratory phenotype and SDF-1α-induced chemotaxis are cholesterol depletion-sensitive. Finally, GM3 and GM1 raft redistribution requires an intact actin cytoskeleton, but is insensitive to microtubule disruption. We propose that membrane protein segregation not only between raft and nonraft domains but also between distinct raft subdomains may be an organizational principle that mediates redistribution of specialized molecules needed for T cell migration.
  Proceedings of the National Academy of Sciences 08/2001; 98(17):9642-9647. · 9.68 Impact Factor