The Experts below are selected from a list of 1413 Experts worldwide ranked by ideXlab platform
Daniele Piomelli - One of the best experts on this subject based on the ideXlab platform.
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Ablation of Acid Ceramidase Impairs Autophagy and Mitochondria Activity in Melanoma Cells.
International journal of molecular sciences, 2021Co-Authors: Michele Lai, Daniele Piomelli, Veronica La Rocca, Rachele Amato, Giulia Freer, Mario Costa, Pietro Giorgio Spezia, Paola Quaranta, Giuseppe Lombardo, Mauro PistelloAbstract:Cutaneous melanoma is often resistant to therapy due to its high plasticity, as well as its ability to metabolise chemotherapeutic drugs. Sphingolipid signalling plays a pivotal role in its progression and metastasis. One of the ways melanoma alters sphingolipid rheostat is via over-expression of lysosomal Acid Ceramidase (AC), which catalyses the hydrolysis of pro-apoptotic long-chain ceramides into sphingosine and fatty Acid. In this report, we examine the role of Acid Ceramidase in maintaining cellular homeostasis through the regulation of autophagy and mitochondrial activity in melanoma cell lines. We show that under baseline conditions, wild-type melanoma cells had 3-fold higher levels of the autophagy marker, microtubule-associated proteins 1A/1B light chain 3B (LC3 II), compared to AC-null cells. This difference was further magnified after cell starvation. Moreover, we noticed autophagy impairment in A375 AC-null cells, possibly due to local accumulation of non-metabolized ceramides. Nonetheless, we observed that AC-null cells exhibited a significant increase in mitochondrial membrane potential compared to control cells. Consistent with this observation, we found that, after total starvation, ~30% of AC-null cells undergo apoptosis compared to ~6% of wild-type cells. As expected, AC transfection restored viability in A375 AC-null cells. Together, these findings suggest that AC-null melanoma cells change and adapt their metabolism to survive in the absence of AC, although in a way that does not allow them to cope with the stress of nutrient deprivation.
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Complete Acid Ceramidase ablation prevents cancer-initiating cell formation in melanoma cells.
Scientific reports, 2017Co-Authors: Michele Lai, Natalia Realini, Mauro Pistello, Marco La Ferla, Ilaria Passalacqua, Giulia Matteoli, Anand K. Ganesan, Chiara Maria Mazzanti, Daniele PiomelliAbstract:Acid Ceramidase (AC) is a lysosomal cysteine hydrolase that catalyzes the conversion of ceramide into fatty Acid and sphingosine. This reaction lowers intracellular ceramide levels and concomitantly generates sphingosine used for sphingosine-1-phosphate (S1P) production. Since increases in ceramide and consequent decreases of S1P reduce proliferation of various cancers, AC might offer a new target for anti-tumor therapy. Here we used CrispR-Cas9-mediated gene editing to delete the gene encoding for AC, ASAH1, in human A375 melanoma cells. ASAH1-null clones show significantly greater accumulation of long-chain saturated ceramides that are substrate for AC. As seen with administration of exogenous ceramide, AC ablation blocks cell cycle progression and accelerates senescence. Importantly, ASAH1-null cells also lose the ability to form cancer-initiating cells and to undergo self-renewal, which is suggestive of a key role for AC in maintaining malignancy and self-renewal of invasive melanoma cells. The results suggest that AC inhibitors might find therapeutic use as adjuvant therapy for advanced melanoma.
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pyrazole based Acid Ceramidase inhibitors design synthesis and structure activity relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Pyrazole-Based Acid Ceramidase Inhibitors: Design, Synthesis, and Structure–Activity Relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Benzoxazolone Carboxamides as Potent Acid Ceramidase Inhibitors: Synthesis and Structure–Activity Relationship (SAR) Studies
Journal of medicinal chemistry, 2015Co-Authors: Anders Bach, Valentina Vozella, Rita Scarpelli, Daniela Pizzirani, Natalia Realini, Laurin Melzig, Ilaria Penna, Debora Russo, Daniele PiomelliAbstract:Ceramides are lipid-derived intracellular messengers involved in the control of senescence, inflammation, and apoptosis. The cysteine amidase, Acid Ceramidase (AC), hydrolyzes these substances into sphingosine and fatty Acid and, by doing so, regulates their signaling activity. AC inhibitors may be useful in the treatment of pathological conditions, such as cancer, in which ceramide levels are abnormally reduced. Here, we present a systematic SAR investigation of the benzoxazolone carboxamides, a recently described class of AC inhibitors that display high potency and systemic activity in mice. We examined a diverse series of substitutions on both benzoxazolone ring and carboxamide side chain. Several modifications enhanced potency and stability, and one key compound with a balanced activity-stability profile (14) was found to inhibit AC activity in mouse lungs and cerebral cortex after systemic administration. The results expand our arsenal of AC inhibitors, thereby facilitating the use of these compounds as pharmacological tools and their potential development as drug leads.
Daniela Pizzirani - One of the best experts on this subject based on the ideXlab platform.
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pyrazole based Acid Ceramidase inhibitors design synthesis and structure activity relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Pyrazole-Based Acid Ceramidase Inhibitors: Design, Synthesis, and Structure–Activity Relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Benzoxazolone Carboxamides as Potent Acid Ceramidase Inhibitors: Synthesis and Structure–Activity Relationship (SAR) Studies
Journal of medicinal chemistry, 2015Co-Authors: Anders Bach, Valentina Vozella, Rita Scarpelli, Daniela Pizzirani, Natalia Realini, Laurin Melzig, Ilaria Penna, Debora Russo, Daniele PiomelliAbstract:Ceramides are lipid-derived intracellular messengers involved in the control of senescence, inflammation, and apoptosis. The cysteine amidase, Acid Ceramidase (AC), hydrolyzes these substances into sphingosine and fatty Acid and, by doing so, regulates their signaling activity. AC inhibitors may be useful in the treatment of pathological conditions, such as cancer, in which ceramide levels are abnormally reduced. Here, we present a systematic SAR investigation of the benzoxazolone carboxamides, a recently described class of AC inhibitors that display high potency and systemic activity in mice. We examined a diverse series of substitutions on both benzoxazolone ring and carboxamide side chain. Several modifications enhanced potency and stability, and one key compound with a balanced activity-stability profile (14) was found to inhibit AC activity in mouse lungs and cerebral cortex after systemic administration. The results expand our arsenal of AC inhibitors, thereby facilitating the use of these compounds as pharmacological tools and their potential development as drug leads.
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Acid Ceramidase in Melanoma: Expression, Localization and Effects of Pharmacological Inhibition
The Journal of biological chemistry, 2015Co-Authors: Natalia Realini, Daniela Pizzirani, Anders Bach, Anand K. Ganesan, Francesca Palese, Silvia Pontis, Abdul Basit, Daniele PiomelliAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC-regulated sphingolipid signaling in melanoma. We found that AC expression is markedly elevated in normal human melanocytes and proliferative melanoma cell lines, compared with other skin cells (keratinocytes and fibroblasts) and non-melanoma cancer cells. High AC expression was also observed in biopsies from human subjects with Stage II melanoma. Immunofluorescence studies revealed that the subcellular localization of AC differs between melanocytes (where it is found in both cytosol and nucleus) and melanoma cells (where it is primarily localized to cytosol). In addition to having high AC levels, melanoma cells generate lower amounts of ceramides than normal melanocytes do. This down-regulation in ceramide production appears to result from suppression of the de novo biosynthesis pathway. To test whether AC might contribute to melanoma cell proliferation, we blocked AC activity using a new potent (IC50 = 12 nM) and stable inhibitor. AC inhibition increased cellular ceramide levels, decreased sphingosine 1-phosphate levels, and acted synergistically with several, albeit not all, antitumoral agents. The results suggest that AC-controlled sphingolipid metabolism may play an important role in the control of melanoma proliferation.
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Benzoxazolone Carboxamides as Potent Acid Ceramidase Inhibitors: Synthesis and Structure-Activity Relationship (SAR) Studies
Journal of Medicinal Chemistry, 2015Co-Authors: Anders Bach, Valentina Vozella, Rita Scarpelli, Daniela Pizzirani, Natalia Realini, Laurin Melzig, Ilaria Penna, Debora Russo, Daniele PiomelliAbstract:Ceramides are lipid-derived intracellular messengers involved in the control of senescence, inflammation, and apoptosis. The cysteine amidase, Acid Ceramidase (AC), hydrolyzes these substances into sphingosine and fatty Acid and, by doing so, regulates their signaling activity. AC inhibitors may be useful in the treatment of pathological conditions, such as cancer, in which ceramide levels are abnormally reduced. Here, we present a systematic SAR investigation of the benzoxazolone carboxamides, a recently described class of AC inhibitors that display high potency and systemic activity in mice. We examined a diverse series of substitutions on both benzoxazolone ring and carboxamide side chain. Several modifications enhanced potency and stability, and one key compound with a balanced activity?stability profile (14) was found to inhibit AC activity in mouse lungs and cerebral cortex after systemic administration. The results expand our arsenal of AC inhibitors, thereby facilitating the use of these compounds as pharmacological tools and their potential development as drug leads.
Natalia Realini - One of the best experts on this subject based on the ideXlab platform.
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Lead Optimization of Benzoxazolone Carboxamides as Orally Bioavailable and CNS Penetrant Acid Ceramidase Inhibitors.
Journal of medicinal chemistry, 2020Co-Authors: Simona Di Martino, Natalia Realini, Ilaria Penna, Debora Russo, Piero Tardia, Vincenzo Cilibrasi, Samantha Caputo, Marco Mazzonna, Natasha Margaroli, Marco MiglioreAbstract:Sphingolipids (SphLs) are a diverse class of molecules that are regulated by a complex network of enzymatic pathways. A disturbance in these pathways leads to lipid accumulation and initiation of several SphL-related disorders. Acid Ceramidase is one of the key enzymes that regulate the metabolism of ceramides and glycosphingolipids, which are important members of the SphL family. Herein, we describe the lead optimization studies of benzoxazolone carboxamides resulting in piperidine 22m, where we demonstrated target engagement in two animal models of neuropathic lysosomal storage diseases (LSDs), Gaucher's and Krabbe's diseases. After daily intraperitoneal administration at 90 mg kg-1, 22m significantly reduced the brain levels of the toxic lipids glucosylsphingosine (GluSph) in 4L;C* mice and galactosylsphingosine (GalSph) in Twitcher mice. We believe that 22m is a lead molecule that can be further developed for the correction of severe neurological LSDs where GluSph or GalSph play a significant role in disease pathogenesis.
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Complete Acid Ceramidase ablation prevents cancer-initiating cell formation in melanoma cells.
Scientific reports, 2017Co-Authors: Michele Lai, Natalia Realini, Mauro Pistello, Marco La Ferla, Ilaria Passalacqua, Giulia Matteoli, Anand K. Ganesan, Chiara Maria Mazzanti, Daniele PiomelliAbstract:Acid Ceramidase (AC) is a lysosomal cysteine hydrolase that catalyzes the conversion of ceramide into fatty Acid and sphingosine. This reaction lowers intracellular ceramide levels and concomitantly generates sphingosine used for sphingosine-1-phosphate (S1P) production. Since increases in ceramide and consequent decreases of S1P reduce proliferation of various cancers, AC might offer a new target for anti-tumor therapy. Here we used CrispR-Cas9-mediated gene editing to delete the gene encoding for AC, ASAH1, in human A375 melanoma cells. ASAH1-null clones show significantly greater accumulation of long-chain saturated ceramides that are substrate for AC. As seen with administration of exogenous ceramide, AC ablation blocks cell cycle progression and accelerates senescence. Importantly, ASAH1-null cells also lose the ability to form cancer-initiating cells and to undergo self-renewal, which is suggestive of a key role for AC in maintaining malignancy and self-renewal of invasive melanoma cells. The results suggest that AC inhibitors might find therapeutic use as adjuvant therapy for advanced melanoma.
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pyrazole based Acid Ceramidase inhibitors design synthesis and structure activity relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Pyrazole-Based Acid Ceramidase Inhibitors: Design, Synthesis, and Structure–Activity Relationships
Synthesis, 2016Co-Authors: Eleonora Diamanti, Natalia Realini, Daniele Piomelli, Chiara Pagliuca, Giovanni Bottegoni, Luca Goldoni, Fabio Bertozzi, Daniela PizziraniAbstract:Acid Ceramidase (AC) is a lysosomal cysteine amidase responsible for the cleavage of ceramide into sphingosine, which is then phosphorylated to sphingosine 1-phosphate. AC regulates the intracellular levels of ceramide and sphingosine, and AC inhibition may be useful in the treatment of disorders, such as cancer, in which ceramide-mediated signaling may be dysfunctional. Despite their potential experimental and therapeutic value, the number of available small-molecule inhibitors of AC activity remains limited. In the present study is described the discovery of a class of potent pyrazole carboxamide-based AC inhibitors, which were identified using the atomic property field (APF) approach and developed through systematic SAR investigations and in vitro pharmacological characterization. The best compound of this series inhibits AC with nanomolar potency and causes ceramide accumulation and sphingosine depletion in intact G361 proliferative melanoma cells. By expanding the current armamentarium of AC inhibitors, these results should facilitate future efforts to unravel the biology of AC and the therapeutic potential of its inhibition.
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Benzoxazolone Carboxamides as Potent Acid Ceramidase Inhibitors: Synthesis and Structure–Activity Relationship (SAR) Studies
Journal of medicinal chemistry, 2015Co-Authors: Anders Bach, Valentina Vozella, Rita Scarpelli, Daniela Pizzirani, Natalia Realini, Laurin Melzig, Ilaria Penna, Debora Russo, Daniele PiomelliAbstract:Ceramides are lipid-derived intracellular messengers involved in the control of senescence, inflammation, and apoptosis. The cysteine amidase, Acid Ceramidase (AC), hydrolyzes these substances into sphingosine and fatty Acid and, by doing so, regulates their signaling activity. AC inhibitors may be useful in the treatment of pathological conditions, such as cancer, in which ceramide levels are abnormally reduced. Here, we present a systematic SAR investigation of the benzoxazolone carboxamides, a recently described class of AC inhibitors that display high potency and systemic activity in mice. We examined a diverse series of substitutions on both benzoxazolone ring and carboxamide side chain. Several modifications enhanced potency and stability, and one key compound with a balanced activity-stability profile (14) was found to inhibit AC activity in mouse lungs and cerebral cortex after systemic administration. The results expand our arsenal of AC inhibitors, thereby facilitating the use of these compounds as pharmacological tools and their potential development as drug leads.
Edward H. Schuchman - One of the best experts on this subject based on the ideXlab platform.
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Activity-Based Imaging of Acid Ceramidase in Living Cells.
Journal of the American Chemical Society, 2019Co-Authors: Yadira F Ordonez, Edward H. Schuchman, Thierry Levade, Virginie Garcia, Jose Luis Abad, Mazen Aseeri, Josefina Casas, Mireia Casasampere, Antonio Delgado, Gemma TriolaAbstract:Acid Ceramidase (AC) hydrolyzes ceramides into sphingoid bases and fatty Acids. The enzyme is overexpressed in several types of cancer and Alzheimer’s disease, and its genetic defect causes different incurable disorders. The availability of a method for the specific visualization of catalytically active AC in intracellular compartments is crucial for diagnosis and follow-up of therapeutic strategies in diseases linked to altered AC activity. This work was undertaken to develop activity-based probes for the detection of AC. Several analogues of the AC inhibitor SABRAC were synthesized and found to act as very potent (two-digit nM range) irreversible AC inhibitors by reaction with the active site Cys143. Detection of active AC in cell-free systems was achieved either by using fluorescent SABRAC analogues or by click chemistry with an azide-substituted analogue. The compound affording the best features allowed the unprecedented labeling of active AC in living cells.
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activity based imaging of Acid Ceramidase in living cells
Journal of the American Chemical Society, 2019Co-Authors: Yadira F Ordonez, Edward H. Schuchman, Thierry Levade, Virginie Garcia, Jose Luis Abad, Mazen Aseeri, Josefina Casas, Mireia Casasampere, Antonio DelgadoAbstract:Acid Ceramidase (AC) hydrolyzes ceramides into sphingoid bases and fatty Acids. The enzyme is overexpressed in several types of cancer and Alzheimer’s disease, and its genetic defect causes differe...
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Signalling Effects Induced by Acid Ceramidase in Human Epithelial Or Leukemic Cell Lines.
Cellular physiology and biochemistry : international journal of experimental cellular physiology biochemistry and pharmacology, 2019Co-Authors: Käthe Baduva, Katrin Anne Becker, Michael J. Edwards, Edward H. Schuchman, Lara Büchter, Katja Kreyenkamp, Linnea Westphal, Barbara Wilker, Marcus Kohnen, Erich GulbinsAbstract:BACKGROUND/AIMS Recent studies indicated that an inhalation treatment of cystic fibrosis mice with Acid Ceramidase prevents and eliminates infections with Pseudomonas aeruginosa and Stapyhlococcus aureus. Inhalation of Acid Ceramidase facilitated the elimination of P. aeruginosa in acutely- or chronically-infected mice with cystic fibrosis. Thus, inhalation of Acid Ceramidase might be a preventive and/or curative treatment for patients with cystic fibrosis suffering from pneumonia. METHODS We treated cultured epithelial cells or leukemic T-lymphocytes (Jurkat cells) with purified Acid Ceramidase and determined intracellular signalling events, proliferation and cell survival. Specifically, we measured the activity of AKT, p38-kinase and p70S6-kinase using activation-specific phospho-antibodies in western blot studies. Trypan Blue staining served to analyze proliferation and cell survival. RESULTS Our studies indicate that treatment of Chang epithelial cells or Jurkat T lymphocytes with purified Acid Ceramidase results in a dose dependent activation of AKT, p38-kinase and p70S6-kinase, while tyrosine phosphorylation of intracellular proteins remains largely unchanged. Acid Ceramidase treatment did not change expression of tight junction proteins such as ZO-1, ZO-2 and occludin. Cellular viability and proliferation were not affected by Acid Ceramidase treatment. CONCLUSION Our data suggest that treatment of epithelial cells and lymphocytes with Acid Ceramidase results in activation of distinct pathways, in particular AKT- and p38K-dependent pathways, while no global activation or cell death was observed.
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Activity-Based Imaging of Acid Ceramidase in Living Cells
2019Co-Authors: Yadira F. Ordóñez, Edward H. Schuchman, Thierry Levade, Virginie Garcia, Mazen Aseeri, Josefina Casas, Mireia Casasampere, Antonio Delgado, José Luís Abad, Gemma TriolaAbstract:Acid Ceramidase (AC) hydrolyzes ceramides into sphingoid bases and fatty Acids. The enzyme is overexpressed in several types of cancer and Alzheimer’s disease, and its genetic defect causes different incurable disorders. The availability of a method for the specific visualization of catalytically active AC in intracellular compartments is crucial for diagnosis and follow-up of therapeutic strategies in diseases linked to altered AC activity. This work was undertaken to develop activity-based probes for the detection of AC. Several analogues of the AC inhibitor SABRAC were synthesized and found to act as very potent (two-digit nM range) irreversible AC inhibitors by reaction with the active site Cys143. Detection of active AC in cell-free systems was achieved either by using fluorescent SABRAC analogues or by click chemistry with an azide-substituted analogue. The compound affording the best features allowed the unprecedented labeling of active AC in living cells
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Polyarticular Arthritis and Spinal Muscular Atrophy in Acid Ceramidase Deficiency.
PEDIATRICS, 2016Co-Authors: Hooi Ling Teoh, Edward H. Schuchman, Alexander Sólyom, David Mowat, Tony Roscioli, Michelle A. Farrar, Hugo SampaioAbstract:Survival of motor neuron 1–negative spinal muscular atrophy (SMA) is heterogeneous and remains a diagnostic challenge. The clinical spectrum continues to expand and ∼33 genes have been identified to date. The present report describes a 9-year-old girl with novel clinical phenotype of a patient with polyarticular arthritis followed by symptoms of SMA due to Acid Ceramidase deficiency. Whole exome sequencing identified compound heterozygous pathogenic mutation in the N-acylsphingosine amidohydrolase 1 gene. Functional assay with leukocyte Acid Ceramidase activity showed a decreased level in the proband confirming pathogenicity of the mutations. Mutations of N-acylsphingosine amidohydrolase 1 are known to separately cause Farber disease (arthritis, subcutaneous nodules, and dysphonia) or SMA with progressive myoclonic epilepsy. The present combined phenotype is novel, bringing together SMA with progressive myoclonic epilepsy and Farber disease and establishing a phenotypic spectrum. Acid Ceramidase deficiency is an important consideration in patients presenting with polyarticular arthritis and motor neuron disease.
Xiang Liu - One of the best experts on this subject based on the ideXlab platform.
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Acid Ceramidase Promotes Nuclear Export of PTEN through Sphingosine 1-Phosphate Mediated Akt Signaling
PloS one, 2013Co-Authors: Thomas H. Beckham, Joseph C Cheng, James S Norris, S. Tucker Marrison, Xiang LiuAbstract:The tumor suppressor PTEN is now understood to regulate cellular processes at the cytoplasmic membrane, where it classically regulates PI3K signaling, as well as in the nucleus where multiple roles in controlling cell cycle and genome stability have been elucidated. Mechanisms that dictate nuclear import and, less extensively, nuclear export of PTEN have been described, however the relevance of these processes in disease states, particularly cancer, remain largely unknown. We investigated the impact of Acid Ceramidase on the nuclear-cytoplasmic trafficking of PTEN. Immunohistochemical analysis of a human prostate tissue microarray revealed that nuclear PTEN was lost in patients whose tumors had elevated Acid Ceramidase. We found that Acid Ceramidase promotes a reduction in nuclear PTEN that is dependent upon sphingosine 1-phosphate-mediated activation of Akt. We were further able to show that sphingosine 1-phosphate promotes formation of a complex between Crm1 and PTEN, and that leptomycin B prevents Acid Ceramidase and sphingosine 1-phosphate mediated loss of nuclear PTEN, suggesting an active exportin-mediated event. To investigate whether the tumor promoting aspects of Acid Ceramidase in prostate cancer depend upon its ability to export PTEN from the nucleus, we used enforced nuclear expression of PTEN to study docetaxel-induced apoptosis and cell killing, proliferation, and xenoengraftment. Interestingly, while Acid Ceramidase was able to protect cells expressing wild type PTEN from docetaxel, promote proliferation and xenoengraftment, Acid Ceramidase had no impact in cells expressing PTEN-NLS. These findings suggest that Acid Ceramidase, through sphingosine 1-phosphate, promotes nuclear export of PTEN as a means of promoting tumor formation, cell proliferation, and resistance to therapy.
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Autophagy is increased in prostate cancer cells overexpressing Acid Ceramidase and enhances resistance to C6 ceramide.
Prostate cancer and prostatic diseases, 2010Co-Authors: Lorianne S. Turner, James S Norris, Thomas H. Beckham, Joe Cheng, Thomas E. Keane, Xiang LiuAbstract:Autophagy is increased in prostate cancer cells overexpressing Acid Ceramidase and enhances resistance to C 6 ceramide
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Acid Ceramidase upregulation in prostate cancer: role in tumor development and implications for therapy.
Expert opinion on therapeutic targets, 2009Co-Authors: Xiang Liu, Yusuf A Hannun, Saeed Elojeimy, Joseph C Cheng, Thomas H. Beckham, Lorianne S. Turner, Alicja Bielawska, Thomas E. Keane, James S NorrisAbstract:Bioactive sphingolipids, such as ceramide, sphingosine and sphingosine-1-phosphate are known bio-effector molecules which play important roles in various aspects of cancer biology including cell proliferation, growth arrest, apoptosis, metastasis, senescence and inflammation. Therefore, enzymes involved in ceramide metabolism are gaining recognition as being critical regulators of cancer cell growth and/or survival. We previously observed that the ceramide metabolizing enzyme, Acid Ceramidase (AC) is upregulated in tumor tissues. Studies have now concluded that this creates a dysfunctional ceramide pathway, which is responsible for tumor progression and resistance to chemotherapy and radiation. This suggests that development of small-molecule drugs that inhibit AC enzyme activity is a promising approach for improving standard cancer therapy and patient’s clinical outcomes.
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Molecular Targeting of Acid Ceramidase: Implications to Cancer Therapy
Current drug targets, 2008Co-Authors: Youssef H Zeidan, James S Norris, Xiang Liu, Russell W. Jenkins, John B. Korman, Lina M. Obeid, Yusuf A HannunAbstract:Increasingly recognized as bioactive molecules, sphingolipids have been studied in a variety of disease models. The impact of sphingolipids on cancer research facilitated the entry of sphingolipid analogues and enzyme modulators into clinical trials. Owing to its ability to regulate two bioactive sphingolipids, ceramide and sphingosine-1-phosphate, Acid Ceramidase (AC) emerges as an attractive target for drug development within the sphingolipid metabolic pathway. Indeed, there is extensive evidence supporting a pivotal role for AC in lipid metabolism and cancer biology. In this article, we review the current knowledge of the biochemical properties of AC, its relevance to tumor promotion, and its molecular targeting approaches.
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Lysosomotropic Acid Ceramidase inhibitor induces apoptosis in prostate cancer cells
Cancer Chemotherapy and Pharmacology, 2008Co-Authors: David H Holman, Saeed Elojeimy, Youssef H Zeidan, Zdzislaw M. Szulc, Xiang Liu, Lorianne S. Turner, Jacek Bielawski, Ahmed El-zawahry, Kristi Norris, Yusuf A HannunAbstract:Purpose Alterations in ceramide metabolism have been reported in prostate cancer (PCa), resulting in escape of cancer cells from ceramide-induced apoptosis. Specifically, increased expression of lysosomal Acid Ceramidase (AC) has been shown in some primary PCa tissues and in several PCa cell lines. To determine if this represents a novel therapeutic target, we designed and synthesized LCL204, a lysosomotropic analog of B13, a previously reported inhibitor of AC Methods Prostate cancer cell lines were treated with LCL204 for varying times and concentrations. Effects of treatment on cytotoxicity, sphingolipid content, and apoptotic markers were assessed. Results Treatment of DU145 PCa cells resulted in increased ceramide and decreased sphingosine levels. Interestingly, LCL204 caused degradation of AC in a cathepsin-dependent manner. We also observed rapid destabilization of lysosomes and the release of lysosomal proteases into the cytosol following treatment with LCL204. Combined, these events resulted in mitochondria depolarization and executioner caspase activation, ultimately ending in apoptosis Conclusions These results provide evidence that treatment with molecules such as LCL204, which restore ceramide levels in PCa cells may serve as a new viable treatment option for PCa.