1
|
Chung LH, Liu D, Liu XT, Qi Y. Ceramide Transfer Protein (CERT): An Overlooked Molecular Player in Cancer. Int J Mol Sci 2021; 22:13184. [PMID: 34947980 PMCID: PMC8705978 DOI: 10.3390/ijms222413184] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/02/2021] [Accepted: 12/05/2021] [Indexed: 12/26/2022] Open
Abstract
Sphingolipids are a class of essential lipids implicated in constructing cellular membranes and regulating nearly all cellular functions. Sphingolipid metabolic network is centered with the ceramide-sphingomyelin axis. Ceramide is well-recognized as a pro-apoptotic signal; while sphingomyelin, as the most abundant type of sphingolipids, is required for cell growth. Therefore, the balance between these two sphingolipids can be critical for cancer cell survival and functioning. Ceramide transfer protein (CERT) dictates the ratio of ceramide to sphingomyelin within the cell. It is the only lipid transfer protein that specifically delivers ceramide from the endoplasmic reticulum to the Golgi apparatus, where ceramide serves as the substrate for sphingomyelin synthesis. In the past two decades, an increasing body of evidence has suggested a critical role of CERT in cancer, but much more intensive efforts are required to draw a definite conclusion. Herein, we review all research findings of CERT, focusing on its molecular structure, cellular functions and implications in cancer. This comprehensive review of CERT will help to better understand the molecular mechanism of cancer and inspire to identify novel druggable targets.
Collapse
Affiliation(s)
- Long Hoa Chung
- Centenary Institute of Cancer Medicine and Cell Biology, University of Sydney, Camperdown, NSW 2050, Australia; (D.L.); (X.T.L.)
| | | | | | - Yanfei Qi
- Centenary Institute of Cancer Medicine and Cell Biology, University of Sydney, Camperdown, NSW 2050, Australia; (D.L.); (X.T.L.)
| |
Collapse
|
2
|
Almomen A, Arafah M, Alwhaibi M, Alsaigh N, Alshememry A, Alsaleh NB, Alrabeeah D, Al Saleh K, Alshamsan A, Alkholief M. Ceramide expression in relation to breast cancer molecular subtypes in Saudi women. Saudi Pharm J 2021; 29:609-615. [PMID: 34194268 PMCID: PMC8233535 DOI: 10.1016/j.jsps.2021.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/18/2021] [Indexed: 11/15/2022] Open
Abstract
Background/Introduction Despite advances in the diagnosis and management of breast cancer (BC), it is still associated with high mortality rates. New biomarkers are being developed for the diagnosis, treatment, and prediction of responses of BC. Ceramide (CER), a bioactive sphingolipid, has emerged recently as a useful diagnostic tool in several types of tumors. In this study, we evaluated CER expression in invasive BC and assessed its relation to the molecular subtypes of BC. Materials and methods The clinical data and histopathological slides of 50 patients with invasive ductal carcinoma were retrieved and reviewed. The cases were then stained with a mouse monoclonal anti-ceramide antibody. Pearson correlation was used to assess the correlation between CER percentage and intensity and other clinical and pathological variables. Results CER expression showed a direct relationship with estrogen and progesterone receptors Allred scores. However, it showed an inverse relation with tumor grade, HER2/neu status and Ki-67 index. Conclusions CER expression is likely to be associated with luminal BC molecular subtypes. However, more research is needed to confirm these results and to explore its relation to the different clinical outcomes, including response to treatment and prognosis.
Collapse
Affiliation(s)
- Aliyah Almomen
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia.,Nanobiotechnology Unit, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia
| | - Maria Arafah
- Department of Pathology, College of Medicine, King Saud University, Riyadh 11495, Saudi Arabia
| | - Monira Alwhaibi
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh 11149, Saudi Arabia
| | - Norah Alsaigh
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia
| | - Abdullah Alshememry
- Nanobiotechnology Unit, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia.,Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia
| | - Nasser B Alsaleh
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Danah Alrabeeah
- Departmnet of Pharmaceutical Services, Prince Sultan Military Medical City, Riyadh 12233, Saudi Arabia
| | - Khalid Al Saleh
- Division of Hematology-Oncology, Oncology Center, King Saud University Medical City, Riyadh 11495, Saudi Arabia
| | - Aws Alshamsan
- Nanobiotechnology Unit, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia.,Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia
| | - Musaed Alkholief
- Nanobiotechnology Unit, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia.,Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11495, Saudi Arabia
| |
Collapse
|
3
|
Lee S, Kang HG, Jeong PS, Kim MJ, Park SH, Song BS, Sim BW, Kim SU. Heat stress impairs oocyte maturation through ceramide-mediated apoptosis in pigs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:144144. [PMID: 33288257 DOI: 10.1016/j.scitotenv.2020.144144] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 06/12/2023]
Abstract
Heat stress (HS) is an emerging issue that greatly impairs the reproductive performance of animals and humans. In particular, disruption of oocyte maturation due to HS is considered a major cause of impaired reproductive performance. HS is known to induce ceramide generation, which causes reactive oxygen species (ROS) production and mitochondrial dysfunction, thereby inducing apoptosis. Therefore, we investigated whether inhibition of ceramide generation ameliorates HS-induced apoptosis in porcine cumulus-oocyte complexes (COCs) using specific inhibitors of the de novo (fumonisin B1, FB1) and hydrolytic pathways (desipramine, Des) of ceramide formation. We investigated the effects of FB1 and Des supplementation under HS conditions (41.5 °C for 44 h) on in vitro maturation (IVM) of porcine COCs. After IVM, HS significantly reduced proportion of COCs exhibiting fully expanded cumulus cells and the rate of metaphase II in oocytes. After parthenogenetic activation (PA), HS significantly reduced the rates of cleavage and blastocyst formation with a lower total cell number and a higher percentage of apoptosis in blastocysts. However, FB1 or Des supplementation under HS avoided detrimental effects of HS on expansion of cumulus cells, nuclear maturation of oocytes, and embryonic development after PA including the rates of cleavage and blastocyst formation, total cell number, and the percentage of apoptosis in blastocysts. Furthermore, FB1 or Des addition under HS, compared with HS alone, significantly decreased ceramide generation, ROS production, cytochrome C expression, and apoptosis and increased mitochondrial membrane potential in COCs, reaching levels comparable with those of the control. Taken together, our results indicate that HS impaired oocyte maturation through ceramide-mediated apoptosis.
Collapse
Affiliation(s)
- Sanghoon Lee
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Hyo-Gu Kang
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Pil-Soo Jeong
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Min Ju Kim
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Soo-Hyun Park
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Bong-Seok Song
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Bo-Woong Sim
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea; National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea
| | - Sun-Uk Kim
- Futuristic Animal Resource & Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea; National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do 28116, Republic of Korea; Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Republic of Korea.
| |
Collapse
|
4
|
Samaha D, Hamdo HH, Wilde M, Prause K, Arenz C. Sphingolipid-Transporting Proteins as Cancer Therapeutic Targets. Int J Mol Sci 2019; 20:ijms20143554. [PMID: 31330821 PMCID: PMC6678544 DOI: 10.3390/ijms20143554] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 01/11/2023] Open
Abstract
The understanding of the role of sphingolipid metabolism in cancer has tremendously increased in the past ten years. Many tumors are characterized by imbalances in sphingolipid metabolism. In many cases, disorders of sphingolipid metabolism are also likely to cause or at least promote cancer. In this review, sphingolipid transport proteins and the processes catalyzed by them are regarded as essential components of sphingolipid metabolism. There is much to suggest that these processes are often rate-limiting steps for metabolism of individual sphingolipid species and thus represent potential target structures for pharmaceutical anticancer research. Here, we summarize empirical and biochemical data on different proteins with key roles in sphingolipid transport and their potential role in cancer.
Collapse
Affiliation(s)
- Doaa Samaha
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
- Depatment of Pharmaceutical Chemistry, College of Pharmacy, Helwan University, Cairo 11795, Egypt
| | - Housam H Hamdo
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Max Wilde
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Kevin Prause
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Christoph Arenz
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
| |
Collapse
|
5
|
Suhrland C, Truman JP, Obeid LM, Sitharaman B. Oxidized graphene nanoparticles as a delivery system for the pro-apoptotic sphingolipid C 6 ceramide. J Biomed Mater Res A 2018; 107:25-37. [PMID: 30422374 DOI: 10.1002/jbm.a.36474] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/16/2018] [Accepted: 05/24/2018] [Indexed: 01/22/2023]
Abstract
Sphingolipids such as ceramide have attracted much attention as possible anticancer agents due to their potent pro-apoptotic effects. However, due to their extreme hydrophobicity, there is currently no clinically approved delivery method for in vivo use as a therapeutic agent. To this end, we have developed a novel method for loading the short-chain C6 ceramide onto oxidized graphene nanoribbons (O-GNRs) and graphene nanoplatelets (GNPs). Mass spectrometry revealed loading efficiencies of 57% and 51.5% for C6 ceramide onto O-GNRs and GNPs, respectively. The PrestoBlue viability assay revealed that 100 µg/mL of C6 ceramide-loaded O-GNRs and C6 ceramide-loaded GNPs reduced HeLa cell viability by approximately 93% and approximately 76%, respectively, compared to untreated HeLa cells, while equal concentrations of these nanoparticles without C6 ceramide did not significantly reduce HeLa cell viability. We confirmed that this cytotoxicity was apoptotic in nature via capase-3 activity and Hoechst staining. Using live-cell confocal imaging with the fluorescent NBD-ceramide loaded on O-GNRs, we observed robust uptake into HeLa cells within 30 min while NBD-ceramide on its own was uptaken much more rapidly. Transmission electron microscopy confirmed that C6 ceramide-loaded O-GNRs were actually entering cells. Taken together, these data show that O-GNRs are a promising delivery agent for ceramide. To our knowledge, this study is the first to use such a loading method. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 25-37, 2019.
Collapse
Affiliation(s)
- Cassandra Suhrland
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York
| | - Jean-Philip Truman
- Department of Medicine and the Stony Brook Cancer Center, Health Science Center, Stony Brook University, New York, New York
| | - Lina M Obeid
- Department of Medicine and the Stony Brook Cancer Center, Health Science Center, Stony Brook University, New York, New York
| | - Balaji Sitharaman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York
| |
Collapse
|
6
|
Metabolic Conversion of Ceramides in HeLa Cells - A Cholesteryl Phosphocholine Delivery Approach. PLoS One 2015; 10:e0143385. [PMID: 26599810 PMCID: PMC4658033 DOI: 10.1371/journal.pone.0143385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/04/2015] [Indexed: 11/19/2022] Open
Abstract
Ceramides can be delivered to cultured cells without solvents in the form of complexes with cholesteryl phosphocholine. We have analysed the delivery of three different radiolabeled D-erythro-ceramides (C6-Cer, C10-Cer and C16-Cer) to HeLa cells, and followed their metabolism as well as the cell viability. We found that all three ceramides were successfully taken up by HeLa cells when complexed to CholPC in an equimolar ratio, and show that the ceramides show different rates of cellular uptake and metabolic fate. The C6-Cer had the highest incorporation rate, followed by C10-Cer and C16-Cer, respectively. The subsequent effect on cell viability strongly correlated with the rate of incorporation, where C6-Cer had the strongest apoptotic effects. Low-dose (1 μM) treatment with C6-Cer favoured conversion of the precursor to sphingomyelin, whereas higher concentrations (25–100 μM) yielded increased conversion to C6-glucosylceramide. Similar results were obtained for C10-Cer. In the lower-dose C16-Cer experiments, most of the precursor was degraded, whereas at high-dose concentrations the precursor remained un-metabolized. Using this method, we demonstrate that ceramides with different chain lengths clearly exhibit varying rates of cellular uptake. The cellular fate of the externally delivered ceramides are clearly connected to their rate of incorporation and their subsequent effects on cell viability may be in part determined by their chain length.
Collapse
|
7
|
Renault TT, Chipuk JE. Inter-organellar communication with mitochondria regulates both the intrinsic and extrinsic pathways of apoptosis. Commun Integr Biol 2013; 6:e22872. [PMID: 23750296 PMCID: PMC3609836 DOI: 10.4161/cib.22872] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/13/2012] [Indexed: 01/11/2023] Open
Abstract
One of our major research interests is to define BCL-2 family function in the cellular decision to induce mitochondrial outer membrane permeabilization and apoptosis. Curiosity in BCL-2 family - mitochondrial interactions led to the identification that the sphingolipid pathway plays a crucial role in BCL-2 family function. For approximately 20 years, sphingolipid biology and apoptotic mechanisms have criss-crossed, but remained distinct, as neither literature could explain the observable interplay between these pathways. We recently identified that two products within the sphingolipid pathway, sphingosine-1-PO4 and hexadecenal, directly regulate BAK and BAX activation, respectively. Furthermore, our work suggests that mitochondrial communication with heterotypic membrane and/or organelles may be an important regulatory mechanism for apoptotic sensitivity.
Collapse
Affiliation(s)
- Thibaud T Renault
- Department of Oncological Sciences; Mount Sinai School of Medicine; New York, NY USA ; The Tisch Cancer Institute; New York, NY USA
| | | |
Collapse
|
8
|
Vera B, Santa Cruz S, Magnarelli G. Plasma cholinesterase and carboxylesterase activities and nuclear and mitochondrial lipid composition of human placenta associated with maternal exposure to pesticides. Reprod Toxicol 2012; 34:402-7. [DOI: 10.1016/j.reprotox.2012.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/02/2012] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
|
9
|
Mondal S, Roy S, Maity R, Mallick A, Sangwan R, Misra-Bhattacharya S, Mandal C. Withanolide D, carrying the baton of Indian rasayana herb as a lead candidate of antileukemic agent in modern medicine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 749:295-312. [PMID: 22695853 DOI: 10.1007/978-1-4614-3381-1_20] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Susmita Mondal
- Cancer Biology and Inflammatory Diseases, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | | | | | | | | | | | | |
Collapse
|
10
|
Apoptotic sphingolipid ceramide in cancer therapy. J Lipids 2011; 2011:565316. [PMID: 21490804 PMCID: PMC3066853 DOI: 10.1155/2011/565316] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/26/2010] [Indexed: 11/18/2022] Open
Abstract
Apoptosis, also called programmed cell death, is physiologically and pathologically involved in cellular homeostasis. Escape of apoptotic signaling is a critical strategy commonly used for cancer tumorigenesis. Ceramide, a derivative of sphingolipid breakdown products, acts as second messenger for multiple extracellular stimuli including growth factors, chemical agents, and environmental stresses, such as hypoxia, and heat stress as well as irradiation. Also, ceramide acts as tumor-suppressor lipid because a variety of stress stimuli cause apoptosis by increasing intracellular ceramide to initiate apoptotic signaling. Defects on ceramide generation and sphingolipid metabolism are developed for cancer cell survival and cancer therapy resistance. Alternatively, targeting ceramide metabolism to correct these defects might provide opportunities to overcome cancer therapy resistance.
Collapse
|
11
|
Mondal S, Mandal C, Sangwan R, Chandra S, Mandal C. Withanolide D induces apoptosis in leukemia by targeting the activation of neutral sphingomyelinase-ceramide cascade mediated by synergistic activation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. Mol Cancer 2010; 9:239. [PMID: 20836852 PMCID: PMC2949798 DOI: 10.1186/1476-4598-9-239] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 09/13/2010] [Indexed: 01/16/2023] Open
Abstract
Background Ceramide is an important second messenger that has diverse cellular and biological effect. It is a specific and potent inducer of apoptosis and suppressor of cell growth. In leukemia, chemoresistance generally developed due to deregulated ceramide metabolism. In combinatorial treatment strategies of leukemia, few components have the capability to increases ceramide production. Manipulation in ceramide production by physiological and pharmacological modulators therefore will give additive effect in leukemia chemotherapy. Results Here, we show that Withanolide D (C4β-C5β,C6β-epoxy-1-oxo-,20β, dihydroxy-20S,22R-witha-2,24-dienolide; WithaD), a pure herbal compound isolated from Withania somnifera could effectively induces apoptosis in a dose and time dependant manner both in myeloid (K562) and lymphoid (MOLT-4) cells being nontoxic to normal lymphocytes and control proliferative cells. WithaD potentially augment ceramide production in these cells. Downstream of ceramide, WithaD acted on MKK group of proteins and significantly increased JNK and p38MAPK phosphorylation. Pharmacological inhibition of p38MAPK and JNK proves their cooperative action on WithaD-induced cell death. Dissecting the cause of ceramide production, we found activation of neutral sphingomyelinase and showed neutral-sphingomyelinase 2 (N-SMase 2) is a critical mediator of WithaD-induced apoptosis. Knockdown of N-SMase 2 by siRNA and inhibitor of N-SMase (GW4869) significantly reduced WithaD-induced ceramide generation and phosphorylation of MKK4 and MKK3/6, whereas phosphorylation of MKK7 was moderately regulated in leukemic cells. Also, both by silencing of N-SMase 2 and/or blocking by GW4869 protects these cells from WithaD-mediated death and suppressed apoptosis, whereas Fumonisin B1, an inhibitor of ceramide synthase, did not have any effect. Additionally, WithaD effectively induced apoptosis in freshly isolated lymphoblasts from patients and the potent cell killing activity was through JNK and p38MAPK activation. Conclusion Our results demonstrate that WithaD enhance the ceramide accumulation by activating N-SMase 2, modulate phosphorylation of the JNK and p38MAPK and induced apoptosis in both myeloid and lymphoid cells along with primary cells derived from leukemia patients. Taken together, this pure herbal compound (WithaD) may consider as a potential alternative tool with additive effects in conjunction with traditional chemotherapeutic treatment, thereby accelerate the process of conventional drug development.
Collapse
Affiliation(s)
- Susmita Mondal
- Infectious diseases and immunology Division, Indian Institute of Chemical Biology, A Unit of Council of Scientific and Industrial Research, Govt, of India; 4, Raja S, C, Mullick Road, Kolkata 700032, India.
| | | | | | | | | |
Collapse
|
12
|
McCourt PC, Morgan JM, Nickels JT. Stress-induced ceramide-activated protein phosphatase can compensate for loss of amphiphysin-like activity in Saccharomyces cerevisiae and functions to reinitiate endocytosis. J Biol Chem 2009; 284:11930-41. [PMID: 19254955 DOI: 10.1074/jbc.m900857200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Saccharomyces cerevisiae cells lacking the amphiphysin-like orthologs, Rvs161 or Rvs167, are unable to thrive under many stress conditions. Here we show cells lacking Rvs161 require Cdc55, the B subunit of the yeast ceramide-activated protein phosphatase, for viability under heat stress. By using specific rvs mutant alleles, we linked this lethal genetic interaction to loss of Rvs161 endocytic domain function. Recessive mutations in the sphingolipid pathway, such as deletion of the very long-chain fatty acid elongase, Sur4, suppress the osmotic growth defect of rvs161 cells. We demonstrate that Cdc55 is required for sur4-dependent suppressor activity and that protein phosphatase activation, through overexpression of CDC55 alone, can also remediate this defect. Loss of SUR4 in rvs161 cells reinitiates Ste3 a-factor receptor endocytosis and requires Cdc55 function to do so. Moreover, overexpression of CDC55 reinitiates Ste3 endocytic-dependent degradation and restores fluid phase endocytosis in rvs161 cells. In contrast, loss of SUR4 or CDC55 overexpression does not remediate the actin polarization defects of osmotic stressed rvs161 cells. Importantly, remediation of rvs161 defects by protein phosphatase activation requires the ceramide-activated protein phosphatase catalytic subunit, Sit4, and the protein phosphatase 2A catalytic subunits, Pph21/Pph22. Finally, genetic analyses reveal a synthetic lethal interaction between loss of CDC55 and gene deletions lethal with rvs161, all of which function in endocytosis.
Collapse
Affiliation(s)
- Paula C McCourt
- Pharmacogenomics Division, Medical Diagnostics Laboratories, LLC, Hamilton, New Jersey 08690, USA
| | | | | |
Collapse
|
13
|
Kim S, Kim Y, Lee Y, Chung JH. Ceramide accelerates ultraviolet-induced MMP-1 expression through JAK1/STAT-1 pathway in cultured human dermal fibroblasts. J Lipid Res 2008; 49:2571-81. [DOI: 10.1194/jlr.m800112-jlr200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
|
14
|
Chess DJ, Stanley WC. Role of diet and fuel overabundance in the development and progression of heart failure. Cardiovasc Res 2008; 79:269-78. [PMID: 18343896 DOI: 10.1093/cvr/cvn074] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Under physiological conditions, the human heart derives energy from glucose, fatty acids, and/or lactate depending upon substrate availability, circulating hormone levels, and nutritional status. Circulating free fatty acid and glucose levels often exceed the normal range, as observed with type 2 diabetes, obesity, or physical inactivity. Chronic exposure of the heart to high plasma levels of free fatty acids may cause accumulation of toxic lipid intermediates within cardiomyocytes. Furthermore, suppression of glucose oxidation by increased fatty acid uptake shunts glucose into the oxidative pentose phosphate and hexosamine biosynthetic pathways, both of which yield potentially harmful products. Noxious derivatives of aberrant glucose and fatty acid oxidation can activate signalling cascades leading to myocyte dysfunction or death, processes termed 'glucotoxicity' and 'lipotoxicity'. This review discusses the effects of dietary extremes (e.g. high fat and high carbohydrate consumption) and substrate overabundance in the context of heart failure (HF) development and progression. Emerging data suggest that substrate excess leads to cardiac dysfunction and HF, which may be prevented or slowed by maintaining low body fat and high insulin sensitivity and consuming a diet of low glycaemic load that is high in mono- and polyunsaturated fatty acids.
Collapse
Affiliation(s)
- David J Chess
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | |
Collapse
|
15
|
Szczepaniak LS, Victor RG, Orci L, Unger RH. Forgotten but not gone: the rediscovery of fatty heart, the most common unrecognized disease in America. Circ Res 2007; 101:759-67. [PMID: 17932333 DOI: 10.1161/circresaha.107.160457] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Until 60 years ago, fatty heart was an accepted clinical entity. Since then, its very existence has been questioned, despite the fact that 2 of 3 Americans are now obese or overweight and obesity has been shown to be correlated with cardiac functional abnormalities. In 2000, a syndrome of "lipotoxic cardiomyopathy" resembling earlier pathologic descriptions of fatty human hearts was described in rodents, and fatty infiltration of cardiomyocytes was subsequently reported in patients with congestive failure. Now, magnetic resonance spectroscopy has been adapted to permit routine noninvasive screening for fatty heart. The use of this technique in human volunteers indicates that cardiomyocyte fat correlates well with body mass index and is elevated in uncomplicated obesity. It is more severe when glucose tolerance becomes abnormal or diabetes is present. It is associated with impaired diastolic filling, even in seemingly asymptomatic obese volunteers. Because fatty heart can be readily prevented by lifestyle modification and pharmacologic interventions that reduce caloric intake and increase fatty acid oxidation, it seems important to recognize its existence so as to intervene as early as possible.
Collapse
Affiliation(s)
- Lidia S Szczepaniak
- Department of Internal Medicine, Division of Hypertension, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | | | | | | |
Collapse
|
16
|
Xin M, Deng X. Protein Phosphatase 2A Enhances the Proapoptotic Function of Bax through Dephosphorylation. J Biol Chem 2006; 281:18859-67. [PMID: 16679323 DOI: 10.1074/jbc.m512543200] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bax is a major proapoptotic member of the Bcl2 family that is required for apoptotic cell death. We have recently discovered that Bax phosphorylation at serine 184 induced by nicotine through activation of protein kinase AKT abolishes its proapoptotic function in human lung cancer cells. Here we found that either treatment of cells with the protein phosphatase 2A (PP2A) inhibitor okadaic acid or specific disruption of PP2A activity by expression of SV40 small tumor antigen enhanced Bax phosphorylation, whereas C(2)-ceramide, a potent PP2A activator, reduced nicotine-induced Bax phosphorylation, suggesting that PP2A may function as a physiological Bax phosphatase. PP2A co-localized and interacted with Bax. Purified, active PP2A directly dephosphorylated Bax in vitro. Overexpression of the PP2A catalytic subunit (PP2A/C) suppressed nicotine-stimulated Bax phosphorylation in association with increased apoptotic cell death. By contrast, depletion of PP2A/C by RNA interference enhanced Bax phosphorylation and prolonged cell survival. Mechanistically C(2)-ceramide-induced Bax dephosphorylation caused a conformational change by exposure of the 6A7 epitope (amino acids 13-19) that is normally hidden at its N terminus that promoted the insertion of Bax into mitochondrial membranes and formation of Bax oligomers leading to cytochrome c release and apoptosis. In addition, PP2A directly disrupted the Bcl2/Bax association to liberate Bax from the heterodimer complex. Thus, PP2A may function as a physiological Bax regulatory phosphatase that not only dephosphorylates Bax but also activates its proapoptotic function.
Collapse
Affiliation(s)
- Meiguo Xin
- University of Florida Shands Cancer Center, Gainesville, Florida 32610-0232, USA
| | | |
Collapse
|
17
|
Basu S, Ma R, Mikulla B, Bradley M, Moulton C, Basu M, Banerjee S, Inokuchi JI. Apoptosis of human carcinoma cells in the presence of inhibitors of glycosphingolipid biosynthesis: I. Treatment of Colo-205 and SKBR3 cells with isomers of PDMP and PPMP. Glycoconj J 2005; 20:157-68. [PMID: 15090729 DOI: 10.1023/b:glyc.0000024254.64450.8b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Apoptosis, or programmed cell death, plays an important role in many physiological and diseased conditions. Induction of apoptosis in cancer cells by anti-cancer drugs and biosynthetic inhibitors of cells surface glycolipids in the human colon carcinoma cells (Colo-205) are of interest in recent years. In our present studies, we have employed different stereoisomers of PPMP and PDMP (inhibit GlcT-glycosyltransferase (GlcT-GLT)) to initiate apoptosis in Colo-205 cells grown in culture in the presence of (3)H-TdR and (3)H/or (14)C-L-Serine. Our analysis showed that the above reagents (between 1 to 20 microM) initiated apoptosis with induction of Caspase-3 activities and phenotypic morphological changes in a dose-dependent manner. We have observed an increase of radioactive ceramide formation in the presence of a low concentration (1-4 microM) of these reagents in these cell lines. However, high concentrations (4-20 microM) inhibited incorporation of radioactive serine in the higher glycolipids. Colo-205 cells were treated with L-threo-PPMP (0-20 microM) and activities of different GSL: GLTs were estimated in total Golgi-pellets. The cells contained high activity of GalT-4 (UDP-Gal: LcOse3Cer beta 1-4galactosyltransferase), whereas negligible activity of GalT-3 (UDP-Gal: GM2 beta 1-3galactosyltransferase) or GM2-synthase activity of the ganglioside pathway was detected. Previously, GLTs involved in the biosynthetic pathway of SA-Le(x) formation had been detected in these colon carcinoma (or Colo-205) cells (Basu M et al. Glycobiology 1, 527-35 (1991)). However, during progression of apoptosis in Colo-205 cells with increasing concentrations of L-PPMP, the GalT-4 activity was decreased significantly. These changes in the specific activity of GalT-4 in the total Golgi-membranes could be the resultant of decreased gene expression of the enzyme.
Collapse
Affiliation(s)
- Subhash Basu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Keyhani E, Keyhani J. Plasma Membrane Alteration Is an Early Signaling Event in Doxorubicin-Induced Apoptosis in the YeastCandida utilis. Ann N Y Acad Sci 2004; 1030:369-76. [PMID: 15659819 DOI: 10.1196/annals.1329.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Signaling pathways such as increased ceramide, mitochondrial dysfunction, and P3 and caspase activation are produced by anticancer drugs and lead to apoptosis. In this research we show that the first event after culturing the yeast Candida utilis in the presence of low doses of doxorubicin (25 microg/mL) is the morphological alteration of the plasma membrane. In the presence of higher doxorubicin doses (>/=50 microg/mL), in addition to profound alterations in the plasma membrane, changes in mitochondrial shape and cristae organization were observed. Concomitantly, increases in respiration, substrate oxidation, and cytochrome biosynthesis were observed at low doxorubicin doses (up to 25 microg/mL), whereas a progressive decrease was observed at higher doses. [(3)H]Leu incorporation into proteins increased by 40% in the mitochondrial fraction and by 19% in the cytosol in the presence of 25 microg/mL doxorubicin; it decreased to 80% of the control in the cytosol in the presence of 1 mg/mL doxorubicin. Morphologically, doxorubicin doses of up to 200 microg/mL produced apoptosis, whereas higher doxorubicin doses produced necrosis.
Collapse
Affiliation(s)
- Ezzatollah Keyhani
- Laboratory for Life Sciences, Saadat Abade, Sarve Sharghi 34, 19979 Tehran, Iran.
| | | |
Collapse
|
19
|
Hatano M, Mizuno M, Yoshida J. Enhancement of C2-ceramide antitumor activity by small interfering RNA on X chromosome-linked inhibitor of apoptosis protein in resistant human glioma cells. J Neurosurg 2004; 101:119-27. [PMID: 15255262 DOI: 10.3171/jns.2004.101.1.0119] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Many human glioma cells are resistant to ceramide. In this study the authors investigated the mechanisms of that resistance and considered ways to overcome it. METHODS The authors first administered C2-ceramide (N-acetylsphingosine) to human glioma cells from rare cell lines susceptible to C2-ceramide (SKMG1 and U87MG) and other cell lines resistant to it (U251SP, T98G, SKAO2, and U251MG). Following this, the authors analyzed the statuses of transduction signals such as cell viability, morphological changes, caspases, mitochondrial membrane potential, apoptosis-inducing factor, oligonucleosomal DNA fragmentation, and the inhibitor of apoptosis protein (IAP) family. CONCLUSIONS Ceramide resistance was found to arise from the inhibition of caspase-7 induced by IAPs, especially X chromosome-linked IAP (XIAP). Small interfering RNA (siRNA) on XIAP quenched that resistance in ceramide-resistant human glioma cells (U251SP, T98G, SKAO2, U251MG), indicating that a siRNA for XIAP may be a useful tool for overcoming the resistance to ceramide in human glioma cells.
Collapse
Affiliation(s)
- Manabu Hatano
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | | |
Collapse
|
20
|
Lim KT, Lee SJ, Heo KS, Lim K. Effects of glycoprotein isolated from Rhus verniciflua stokes on TPA-induced apoptosis and production of cytokines in cultured mouse primary splenocytes. Toxicol Lett 2003; 145:261-71. [PMID: 14580897 DOI: 10.1016/s0378-4274(03)00304-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Glycoprotein of Rhus verniciflua Stokes (RVS glycoprotein) was isolated and identified using SDS-PAGE. To study the anti-apoptotic effects of RVS glycoprotein on mouse splenocytes, splenocytes were exposed to 100 nM TPA (61.68 ng/ml) for 3 h with or without RVS glycoprotein (100 microg/ml). Results from our experiment showed that RVS glycoprotein protects from splenocyte apoptosis induced by 12-O-tetradecanoylphorbol 13-acetate (TPA). We also studied the effects of RVS glycoprotein on the proliferation of T/B cells and the production of cytokines. Our results showed that Concanavalin A (Con A)-induced T cell proliferation and the production of interleukin-2 (IL-2)/interleukin-4 (IL-4) were reduced, and that Lipopolysaccharide (LPS)-induced B cell proliferation and the Tumor necrosis factor alpha (TNF-alpha) were reduced significantly by the addition of 50 microg/ml RVS glycoprotein (P<0.01), compared to the control. These results indicate that RVS glycoprotein has the capacity to modulate apoptosis, cytokine production and T/B cell proliferation in splenocytes.
Collapse
Affiliation(s)
- Kye-Taek Lim
- #521, Molecular Biochemistry Laboratory & Biodefensive Substances Group, Institute of Biotechnology, Chonnam National University, 300 Yongbong-Dong, Bukgu, Kwangju 500757, South Korea.
| | | | | | | |
Collapse
|
21
|
Lehne G, Sørensen DR, Tjønnfjord GE, Beiske C, Hagve TA, Rugstad HE, Clausen OPF. The cyclosporin PSC 833 increases survival and delays engraftment of human multidrug-resistant leukemia cells in xenotransplanted NOD-SCID mice. Leukemia 2002; 16:2388-94. [PMID: 12454743 DOI: 10.1038/sj.leu.2402663] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2001] [Accepted: 04/09/2002] [Indexed: 11/09/2022]
Abstract
Circumvention of chemoresistance in cancer may involve several modulator drugs with high affinity for the multidrug transporter P-glycoprotein (Pgp), which is expressed in a number of multi-resistant malignancies. Pgp acts as a membrane efflux pump with broad substrate specificity including antineoplastic drugs and endogenous substances such as certain cytokines and sphingolipids. Therefore, the consequence of Pgp blockade could be far more complex than intracellular drug retention. In the present study exposure of the Pgp inhibitor, PSC 833 (1200 ng/ml), to Pgp expressing KG1a/200 human leukemia cells provoked cell cycle arrest and apoptosis in vitro. This finding was put to test in vivo using a xenotransplant model of KG1a/200 human cells intravenously inoculated into non-obese diabetic severe combined immunodeficient (NOD-SCID) mice. The animals were randomly allocated to receive treatment with PSC 833 (n = 32) or placebo (n = 24). PSC 833 (30 mg/kg) was subcutaneously injected six or 12 times separated by 48-96 h. The overall mean whole blood concentration of PSC 833 was 1191 +/- 60 ng/ml (s.e.m.) at 20 h after administration. Tumor engraftment was significantly reduced in the treatment group (P = 0.037), which also had prolonged survival compared to control animals (P = 0.0016). This is the first study that demonstrates antileukemic effects of a Pgp inhibitor as single agent therapy in vivo, and the present data raise the possibility of alternative exploitation of modulators in cancer chemotherapy.
Collapse
Affiliation(s)
- G Lehne
- Department of Clinical Pharmacology, Rikshospitalet University Hospital, Oslo, Norway
| | | | | | | | | | | | | |
Collapse
|
22
|
Ruvolo PP, Clark W, Mumby M, Gao F, May WS. A functional role for the B56 alpha-subunit of protein phosphatase 2A in ceramide-mediated regulation of Bcl2 phosphorylation status and function. J Biol Chem 2002; 277:22847-52. [PMID: 11929874 DOI: 10.1074/jbc.m201830200] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently it has been shown that the potent apoptotic agent ceramide activates a mitochondrial protein phosphatase 2A (PP2A) and promotes dephosphorylation of the anti-apoptotic molecule Bcl2 (Ruvolo, P. P., Deng, X., Ito, T., Carr, B. K., and May, W. S. (1999) J. Biol. Chem. 274, 20296-20300). In cells expressing Bcl2, dephosphorylation of Bcl2 appears to be required for ceramide-induced cell death because treatment of cells with low doses of the PP2A inhibitor okadaic acid blocks Bcl2 dephosphorylation and promotes cell survival. Furthermore, the non-phosphorylatable (i.e. PP2A-resistant) gain-of-function S70E mutant Bcl2 can protect cells from ceramide-induced apoptosis. These findings support a model whereby Bcl2 function is regulated by PP2A. PP2A is a heterotrimer that contains a catalytic C-subunit, a structural A-subunit, and a regulatory B-subunit. The A- and C-subunits are fairly conserved and ubiquitously expressed, and they form the catalytic complex of the phosphatase. In contrast, there are at least three families of diverse B-subunit molecules that vary in expression temporally and by tissue type. It is hypothesized that ceramide regulates PP2A via the B-subunit. Thus, understanding the mechanism of how PP2A regulates Bcl2 phosphorylation status and how ceramide might regulate this process requires identification of the regulatory B-subunit of PP2A that comprises the Bcl2 phosphatase. Results indicate that the B56 alpha-subunit is a candidate regulatory subunit of the physiologic Bcl2 phosphatase since (a) B56 alpha associates with Bcl2 as evidenced by pull-down experiments, (b) B56 alpha co-localizes with Bcl2 in mitochondrial membranes, (c) ceramide promotes translocation of B56 alpha to mitochondrial membranes, and (d) overexpression of B56 alpha promotes mitochondrial PP2A activity and Bcl2 dephosphorylation and potentiates cell killing with ceramide. These findings suggest a role for B56 alpha in regulating the Bcl2 phosphatase.
Collapse
Affiliation(s)
- Peter P Ruvolo
- Shands Cancer Center and the Department of Medicine, the University of Florida, Gainesville, Florida 32610-0232, USA.
| | | | | | | | | |
Collapse
|
23
|
Shabbits JA, Krishna R, Mayer LD. Molecular and pharmacological strategies to overcome multidrug resistance. Expert Rev Anticancer Ther 2001; 1:585-94. [PMID: 12113091 DOI: 10.1586/14737140.1.4.585] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Multidrug resistance is a major obstacle to the effective treatment of cancer. Despite vast improvements in our understanding of the mechanisms of drug resistance, relatively few significant advances have been made towards effectively circumventing it in a clinical setting. The ability to modulate multidrug resistance has been complicated by the fact that many human tumors simultaneously exhibit multiple resistance mechanisms. In order to effectively overcome multidrug resistance it will be necessary to design new strategies that combine multiple modulating agents and approaches. This review provides an overview of the major causes of multidrug resistance and summarizes many of the current approaches being taken to overcome it. We also describe how liposomal drug delivery systems can be utilized to aid in achieving these goals.
Collapse
Affiliation(s)
- J A Shabbits
- Department of Advanced Therapeutics, BC Cancer Agency, Vancouver, BC, V5Z 4E6, Canada
| | | | | |
Collapse
|
24
|
Komatsu M, Takahashi T, Abe T, Takahashi I, Ida H, Takada G. Evidence for the association of ultraviolet-C and H(2)O(2)-induced apoptosis with acid sphingomyelinase activation. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1533:47-54. [PMID: 11514235 DOI: 10.1016/s1388-1981(01)00139-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Ceramide appears to be a potent second messenger implicated in the regulation of diverse cellular processes such as cell growth and differentiation, gene transcription, ligand binding, and cell death. Environmental stress-induced apoptosis is believed to be associated with the sphingomyelin degradation pathway, which generates ceramide as a second messenger in initiating the apoptosis response. To date, two distinct sphingomyelinases, a lysosomal acid sphingomyelinase (ASM), which is deficient in patients affected with types A and B Niemann-Pick disease (NPD), and a neutral, magnesium-dependent sphingomyelinase (NSM), are candidate enzymes which respond to apoptotic stimulations and cause sphingomyelin hydrolysis and subsequent ceramide generation. Using Epstein-Barr virus (EBV)-transformed lymphoblast cells from type A NPD patient which have defined splicing site mutation in the ASM gene, we showed that ASM-deficient cells were defective in ultraviolet-C (UV-C) and hydrogen peroxide (H(2)O(2)) induced apoptosis. As another induction of apoptosis, we exposed this cell line to serum starvation which influences to p53 expression and leads to apoptosis. There were no differences by the degree of apoptosis between ASM-deficient lymphoblast cells and normal lymphoblast cells. These results are evidence that ASM plays one of the important roles in apoptosis induction by UV-C and H(2)O(2).
Collapse
Affiliation(s)
- M Komatsu
- Department of Pediatrics, Akita University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
The sphingolipid ceramide is an important second signal molecule that regulates diverse signaling pathways involving apoptosis, cell senescence, the cell cycle, and differentiation. For the most part, ceramide's effects are antagonistic to growth and survival. Interestingly, ceramide and the pro-growth agonist, diacylglycerol (DAG) appear to be regulated simultaneously but in opposite directions in the sphingomyelin cycle. While ceramide stimulates signal transduction pathways that are associated with cell death or at least are inhibitory to cell growth (eg stress-activated protein kinase, SAPK, pathways), DAG activates the classical and novel isoforms of the protein kinase C (PKC) family. These PKC isoforms are associated with cell growth and cell survival. Furthermore, DAG activation of PKC stimulates other signal transduction pathways that support cell proliferation (eg mitogen-activated protein kinase, MAPK, pathways). Thus, ceramide and DAG generation may serve to monitor cellular homeostasis by inducing pro-death or pro-growth pathways, respectively. The production of ceramide is emerging as a fixture of programmed cell death. Ceramide levels are elevated in response to diverse stress challenges including chemotherapeutic drug treatment, irradiation, or treatment with pro-death ligands such as tumor necrosis factor alpha, TNF alpha. Consistent with this notion, ceramide itself is a potent apoptogenic agent. Ceramide activates stress-activated protein kinases like c-jun N-terminal kinase (JNK) and thus affects transcription pathways involving c-jun. Ceramide activates protein phosphatases such as protein phosphatase 1 (PP1) and protein phosphatase 2 (PP2A). Ceramide activation of protein phosphatases has been shown to promote inactivation of a number of pro-growth cellular regulators including the kinases PKC alpha and Akt, Bcl2 and the retinoblastoma protein. A new role has recently emerged for ceramide in the regulation of protein synthesis. Ceramide-induced activation of double-stranded RNA-dependent protein kinase (PKR), a protein kinase important in anti-viral host defense mechanisms and recently implicated in cellular stress pathways, results in the inhibition of protein synthesis as a prelude to cell death. Taken together, these properties of ceramide suggest that this important second-signal molecule may have useful properties as an anti-neoplastic agent. Thus, strategies to promote ceramide metabolism or use of ceramide analogs directly may one day become useful in the treatment of diseases like leukemia.
Collapse
Affiliation(s)
- P P Ruvolo
- University of Florida Shands Cancer Center and The Department of Medicine, Gainesville 32610-0232, USA
| |
Collapse
|
26
|
Abstract
BACKGROUND Prostate cancer is the second leading cause of cancer death in men. The most common treatment of prostate cancer is androgen ablation therapy which leads to regression of the tumor due to increased cell death. However, at later stages, the tumor becomes resistant to androgen ablation. Ceramide is a lipid second messenger that mediates cell death in prostate cancer cells. Previous studies suggested that ceramide may cause either apoptosis or growth arrest in the androgen-responsive prostate cancer cell line LNCaP. However, the molecular details of ceramide-induced cell death in LNCaP cells remain to be elucidated. METHODS To investigate the mechanisms of cell death in LNCaP cells, we used various methods, including cell viability assays, fluorescence image analysis, internucleosomal DNA fragmentation analysis, Western blotting, and protein kinase assays. RESULTS Ceramide caused LNCaP cell death without exhibiting typical signs of apoptosis, such as internucleosomal DNA fragmentation and poly(ADP)-ribose-polymerase (PARP) proteolysis. In addition, the general caspase inhibitor z-VAD-fmk did not alter ceramide-induced cell death in LNCaP cells, whereas it efficiently inhibited thapsigargin-induced apoptosis under similar conditions. However, ceramide treatment of LNCaP cells resulted in nuclear fragmentation, which is characteristic of apoptosis. Ceramide induced a strong and prolonged activation of c-Jun N-terminal Kinase (JNK) that correlated very well with the time course of cell death. Whereas the PKC inhibitor bisindolylmaleimide prevented phorbol ester-induced apoptosis in LNCaP cells, it did not affect ceramide-induced cell death. These results suggest that LNCaP cell death induced by ceramide progresses through a novel pathway that is more necrotic than apoptotic.
Collapse
Affiliation(s)
- N Engedal
- Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway
| | | |
Collapse
|
27
|
Craighead M, Pole J, Waters C. Caspases mediate C2-ceramide-induced apoptosis of the human oligodendroglial cell line, MO3.13. Neurosci Lett 2000; 278:125-8. [PMID: 10653009 DOI: 10.1016/s0304-3940(99)00866-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The signalling molecule ceramide participates in the sphingomyelin pathway and accumulates intracellularly in response to inflammatory mediators. Here we show that membrane permeable C2-ceramide is apoptogenic in the immortalised human oligodendroglial cell line MO3.13. Apoptosis (defined by cell shrinkage and chromatin condensation) is accompanied by caspase enzyme activation. Immunoblotting analysis of extracts from differentiated MO3.13 cells revealed the presence of caspase-3 proenzyme, activation by cleavage of pro-caspase-3 in cells treated with C2-ceramide and cleavage of the caspase substrates fodrin and rabaptin. Lysates also showed cleavage of a fluorogenic peptide substrate. Addition of the general caspase inhibitor BAF markedly attenuated apoptosis of MO3.13 oligodendroglia. A role for caspase-3-like enzymes in ceramide-induced apoptosis of oligodendroglia may have important implications for approaches to treatment of demyelinating diseases.
Collapse
Affiliation(s)
- M Craighead
- Division of Neuroscience, Biological Sciences, University of Manchester, UK
| | | | | |
Collapse
|
28
|
del Zoppo G, Ginis I, Hallenbeck JM, Iadecola C, Wang X, Feuerstein GZ. Inflammation and stroke: putative role for cytokines, adhesion molecules and iNOS in brain response to ischemia. Brain Pathol 2000; 10:95-112. [PMID: 10668900 PMCID: PMC8098633 DOI: 10.1111/j.1750-3639.2000.tb00247.x] [Citation(s) in RCA: 457] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Ischemic stroke is a leading cause of death and disability in developed countries. Yet, in spite of substantial research and development efforts, no specific therapy for stroke is available. Several mechanism for neuroprotection have been explored including ion channels, excitatory amino acids and oxygen radicals yet none has culminated in an effective therapeutic effect. The review article on "inflammation and stroke" summarizes key data in support for the possibility that inflammatory cells and mediators are important contributing and confounding factors in ischemic brain injury. In particular, the role of cytokines, endothelial cells and leukocyte adhesion molecules, nitric oxide and cyclooxygenase (COX-2) products are discussed. Furthermore, the potential role for certain cytokines in modulation of brain vulnerability to ischemia is also reviewed. The data suggest that novel therapeutic strategies may evolve from detailed research on some specific inflammatory factors that act in spatial and temporal relationships with traditionally recognized neurotoxic factors. The dual nature of some mediators in reformatting of brain cells for resistance or sensitivity to injury demonstrate the delicate balance needed in interventions based on anti-inflammatory strategies.
Collapse
Affiliation(s)
- G del Zoppo
- The Scripps Research Institute, La Jolla, CA, USA
| | | | | | | | | | | |
Collapse
|
29
|
Liu J, Ginis I, Spatz M, Hallenbeck JM. Hypoxic preconditioning protects cultured neurons against hypoxic stress via TNF-alpha and ceramide. Am J Physiol Cell Physiol 2000; 278:C144-53. [PMID: 10644522 DOI: 10.1152/ajpcell.2000.278.1.c144] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brief "preconditioning" ischemia induces ischemic tolerance (IT) and protects the animal brain from subsequent otherwise lethal ischemia. Identification of the signaling steps most proximal to the development of the IT will allow induction of the resistance to ischemia shortly after the onset of stroke. Animal studies demonstrate a key role of tumor necrosis factor-alpha (TNF-alpha) in induction of IT. The sphingolipid ceramide is known as a second messenger in many of the multiple effects of TNF-alpha. We hypothesized that ceramide could mediate IT. We demonstrate that preconditioning of rat cortical neurons with mild hypoxia protects them from hypoxia and O(2)-glucose deprivation injury 24 h later (50% protection). TNF-alpha pretreatment could be substituted for hypoxic preconditioning (HP). HP was attenuated by TNF-alpha-neutralizing antibody. HP and TNF-alpha pretreatment cause a two- to threefold increase of intracellular ceramide levels, which coincides with the state of tolerance. Fumonisin B(1), an inhibitor of ceramide synthase, attenuated ceramide upregulation and HP. C-2 ceramide added to the cultures right before the hypoxic insult mimicked the effect of HP. Ceramide did not induce apoptosis. These results suggest that HP is mediated via ceramide synthesis triggered by TNF-alpha.
Collapse
Affiliation(s)
- J Liu
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | |
Collapse
|
30
|
Abstract
Apoptosis, the morphology of cell suicide, may result from programmed cell death or may be a response to exogenous stimuli. Apoptosis can be induced in cultured trophoblast and can be identified in the trophoblast of placental villi. The trophoblast regulates maternal-fetal gas, nutrient and waste product exchange; therefore, the presence of apoptosis in this key cellular interface highlights the importance of understanding what controls apoptosis in the placenta. In this review, we describe the signal transduction pathways that trigger apoptosis in other systems, identify key genetic controls for the process and outline the final common pathway which effects execution in cells committed to suicide. Multiplicity, redundancy and cross talk among pathways characterize the surface membrane signals and exogenous stimuli that trigger apoptosis in other cells. As each step in the apoptotic process is discussed, we describe what is known about the step in human placental villi. Recent studies suggest that a further understanding of receptor-mediated signalling pathways, the Bcl-2 regulators and the caspases and substrates involved in placental apoptosis will surely provide insights into both normal placental development and the placental dysfunction associated with some abnormal pregnancies.
Collapse
Affiliation(s)
- R Levy
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St Louis, MO, USA
| | | |
Collapse
|
31
|
The interrelation between the biological functions of sphingolipids and their chemical structure. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2000. [DOI: 10.1007/bf02758855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
32
|
Ruvolo PP, Deng X, Ito T, Carr BK, May WS. Ceramide induces Bcl2 dephosphorylation via a mechanism involving mitochondrial PP2A. J Biol Chem 1999; 274:20296-300. [PMID: 10400650 DOI: 10.1074/jbc.274.29.20296] [Citation(s) in RCA: 270] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphorylation of Bcl2 at serine 70 is required for its potent anti-apoptotic function. We have recently shown that Bcl2 phosphorylation is a dynamic process that involves the protein kinase C alpha and protein phosphatase 2A (PP2A) (Ruvolo, P. P., Deng, X., Carr, B. K., and May, W. S. (1998) J. Biol. Chem. 273, 25436-25442; and Deng, X., Ito, T., Carr, B. K., Mumby, M. C., and May, W. S. (1998) J. Biol. Chem. 273, 34157-34163). The potent apoptotic agent ceramide can activate a PP2A, suggesting that one potential component of the ceramide-induced death signal may involve the inactivation of Bcl2. Results indicate that C2-ceramide but not inactive C2-dihydroceramide, was found to specifically activate a mitochondrial PP2A, which rapidly and completely induced Bcl2 dephosphorylation and correlated closely with ceramide-induced cell death. Using a genetic approach, the gain-of-function S70E Bcl2 mutation, which mimics phosphorylation, fails to undergo apoptosis even with the addition of high doses of ceramide (IC50 > 50 microM). In contrast, cells overexpressing exogenous wild-type Bcl2 were sensitive to ceramide at dosages where PP2A is fully active and Bcl2 would be expected to be dephosphorylated (IC50 = 14 microM). These findings indicate that in cells expressing functional Bcl2, the mechanism of death action for ceramide may involve, at least in part, a mitochondrial PP2A that dephosphorylates and inactivates Bcl2.
Collapse
Affiliation(s)
- P P Ruvolo
- Sealy Center for Oncology and Hematology and Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas 77555-1048, USA
| | | | | | | | | |
Collapse
|
33
|
Lucci A, Han TY, Liu YY, Giuliano AE, Cabot MC. Multidrug resistance modulators and doxorubicin synergize to elevate ceramide levels and elicit apoptosis in drug-resistant cancer cells. Cancer 1999; 86:300-11. [PMID: 10421266 DOI: 10.1002/(sici)1097-0142(19990715)86:2<300::aid-cncr14>3.0.co;2-h] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND To provide insight for the development of more effective clinical agents, the authors attempted to elucidate the mechanisms of action of multidrug resistance (MDR) modulators. Previously, the authors found that MDR modulators blocked the conversion of ceramide to glucosylceramide in MDR cells, thereby enhancing cytotoxicity. Because ceramide is a critical component of the apoptosis signaling cascade, the current study examined the impact of therapy using agents that elicit ceramide formation combined with agents that block ceramide glycosylation. METHODS Doxorubicin-resistant human breast carcinoma cells (MCF-7-AdrR) were treated with either doxorubicin, tamoxifen, cyclosporine A, or the cyclosporine A analog SDZ PSC 833 (PSC 833) or with combinations thereof, and ceramide and glucosylceramide metabolisms were measured by cell radiolabeling. Cell viability was quantitated spectrophotometrically and apoptosis was evaluated analyzing DNA integrity by gel electrophoresis. RESULTS Whereas cyclosporine A blocked the generation of glucosylceramide in MCF-7-AdrR cells, a chemical cousin, PSC 833, elicited a 3-fold increase in glucosylceramide and a 5-fold increase in ceramide levels at 24 hours. The PSC 833 response was time-dependent(as early as 30 minutes) and dose-dependent (as low as 0.1 microM). The appearance of ceramide foreran the generation of glucosylceramide. Sphingomyelin levels were not decreased in response to PSC 833; however, Fumonisin B1, a ceramide synthase inhibitor, blocked PSC 833-induced ceramide generation. Adding tamoxifen, which blocks ceramide glycosylation, to the PSC 833 regimen boosted ceramide levels 11-fold over controls and caused DNA fragmentation. A 3-component regimen comprised of tamoxifen, doxorubicin, and PSC 833 increased ceramide levels 26-fold and brought cell viability to zero. CONCLUSIONS These results demonstrate that MDR modulators can be used separately, in combination, or in conjunction with chemotherapy at clinically relevant concentrations to manipulate cellular ceramide levels and restore sensitivity in the drug resistant setting. As such, this represents a new direction in the treatment of cancer.
Collapse
Affiliation(s)
- A Lucci
- Department of Surgical Oncology, John Wayne Cancer Institute at Saint John's Health Center, Santa Monica, California 90404, USA
| | | | | | | | | |
Collapse
|
34
|
|
35
|
Abstract
Fatty acids are the primary source of energy in the adult heart. Recently, however, it was discovered that certain saturated fatty acids, such as palmitate and stearate, cause cardiac and other types of cells to undergo programmed cell death (apoptosis). In cardiac ischemia/reperfusion injury, where blood flow is blocked and then restored to the heart, recovery of cardiac cells is inversely proportional to the concentration of fatty acids (largely composed of palmitate and stearate) in the reperfusate. The aim of this review is to summarize what is known about fatty acid induction of heart disease, the role of fatty acids in apoptosis, and apoptosis in the heart, including the role that mitochondria play in this process.
Collapse
Affiliation(s)
- G C Sparagna
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston 77030, USA
| | | |
Collapse
|
36
|
Production of TNF-alpha by primary cultures of human keratinocytes challenged with loxosceles gaucho venom. Rev Inst Med Trop Sao Paulo 1999; 41:179-82. [PMID: 10529838 DOI: 10.1590/s0036-46651999000300009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Primary cultures of human keratinocytes were challenged with increasing doses from 10 ng/mL to 2 &mgr;g/mL of Loxosceles gaucho venom, responsible for dermonecrotic lesion in humans. TNF-alpha was investigated by bioassay and ELISA in the supernatant of the cultures challenged with 100 ng/mL, 500 ng/mL, 1 and 2 &mgr;g/mL of venom. TNF-alpha was detected by bioassay in the supernatant of cultures challenged with 100 ng/mL, after 6 h. The cytokine was detected by ELISA in the supernatant of the cells challenged with doses of l &mgr;g/mL, after 6 and 12 h. The results point out the capacity of this venom to activate the keratinocytes in primary cultures to produce TNF-alpha. The production of cytokines could contribute to the local inflammatory process in patients bitten by Loxosceles sp.
Collapse
|
37
|
Ginis I, Schweizer U, Brenner M, Liu J, Azzam N, Spatz M, Hallenbeck JM. TNF-alpha pretreatment prevents subsequent activation of cultured brain cells with TNF-alpha and hypoxia via ceramide. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:C1171-83. [PMID: 10329967 DOI: 10.1152/ajpcell.1999.276.5.c1171] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have developed a cellular model in which cultured astrocytes and brain capillary endothelial cells preconditioned with tumor necrosis factor-alpha (TNF-alpha) fail to upregulate intercellular adhesion molecule-1 (ICAM-1) protein (80% inhibition) and mRNA (30% inhibition) when challenged with TNF-alpha or exposed to hypoxia. Inasmuch as ceramide is known to mediate some of the effects of TNF-alpha, its levels were measured at various times after the TNF-alpha preconditioning. We present evidence for the first time that, in normal brain cells, TNF-alpha pretreatment causes a biphasic increase of ceramide levels: an early peak at 15-20 min, when ceramide levels increased 1.9-fold in astrocytes and 2.7-fold in rat brain capillary endothelial cells, and a delayed 2- to 3-fold ceramide increase that occurs 18-24 h after addition of TNF-alpha. The following findings indicate that the delayed ceramide accumulation results in cell unresponsiveness to TNF-alpha: 1) coincident timing of the ceramide peak and the tolerance period, 2) mimicking of preconditioning by addition of exogenous ceramide, and 3) attenuation of preconditioning by fumonisin B1, an inhibitor of ceramide synthesis. In contrast to observations in transformed cell lines, the delayed ceramide increase was transient and did not induce apoptosis in brain cells.
Collapse
Affiliation(s)
- I Ginis
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
| | | | | | | | | | | | | |
Collapse
|
38
|
Higuchi Y, Matsukawa S. Glutathione depletion induces giant DNA and high-molecular-weight DNA fragmentation associated with apoptosis through lipid peroxidation and protein kinase C activation in C6 glioma cells. Arch Biochem Biophys 1999; 363:33-42. [PMID: 10049497 DOI: 10.1006/abbi.1998.1067] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glutathione (GSH) depletion caused by l-buthionine-(S,R)-sulfoximine (BSO) induced apoptosis that was recognized by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick endo-labeling (TUNEL), nuclear DNA staining with fluorescence dye, and internucleosomal DNA fragmentation in C6 rat glioma cells. The BSO-induced cell death was associated with caspase-3 activation. Lipid peroxidation and protein kinase C (PK-C) activation were observed during the apoptosis of C6 cells, and these events were inhibited by antioxidants and iron chelators without affecting BSO-induced GSH depletion. Furthermore, approximately 2 Mbp giant DNA fragments were observed in the BSO-treated cells. The giant DNA fragmentation were followed by approximately 30-700 kbp and then less than 100 kbp, including internucleosomal DNA fragmentations. Such serial DNA degradation was prevented by the antioxidants, the iron chelators, and the PK-C inhibitors. These results suggest that during apoptosis induced by GSH-depletion caused by BSO, reactive oxygen species endogenously produced cause lipid peroxidation and that the lipid peroxidation induced PK-C activation, processes which are thought to be involved in the giant DNA, high-molecular-weight DNA, and the internucleosomal DNA fragmentations.
Collapse
Affiliation(s)
- Y Higuchi
- Department of Pharmacology, Kanazawa University School of Medicine, Ishikawa, Kanazawa, 920-8640,
| | | |
Collapse
|
39
|
Liu YY, Han TY, Giuliano AE, Cabot MC. Expression of glucosylceramide synthase, converting ceramide to glucosylceramide, confers adriamycin resistance in human breast cancer cells. J Biol Chem 1999; 274:1140-6. [PMID: 9873062 DOI: 10.1074/jbc.274.2.1140] [Citation(s) in RCA: 210] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multidrug-resistant cancer cells display elevated levels of glucosylceramide (Lavie, Y., Cao, H. T., Volner, A., Lucci, A., Han, T. Y., Geffen, V., Giuliano, A. E., and Cabot, M. C. (1997) J. Biol. Chem. 272, 1682-1687). In this study, we have introduced glucosylceramide synthase (GCS) into wild type MCF-7 breast cancer cells using a retroviral tetracycline-on expression system, and we developed a cell line, MCF-7/GCS. MCF-7/GCS cells expressed an 11-fold higher level of GCS activity compared with the parental cell line. Interestingly, the transfected cells demonstrated strong resistance to adriamycin and to ceramide, whereas both agents were highly cytotoxic to MCF-7 cells. The EC50 values of adriamycin and ceramide were 11-fold (p < 0.0005) and 5-fold (p < 0.005) higher, respectively, in MCF-7/GCS cells compared with MCF-7 cells. Ceramide resistance displayed by MCF-7/GCS cells closely paralleled the activity of expressed GCS with a correlation coefficient of 0.99. In turn, cellular resistance and GCS activity were dependent upon the concentration of the expression mediator doxycycline. Adriamycin resistance in MCF-7/GCS cells was related to the hyperglycosylation of ceramide and was not related to shifts in the levels of either P-glycoprotein or Bcl-2. This work demonstrates that overexpression of GCS, which catalyzes ceramide glycosylation, induces resistance to adriamycin and ceramide in MCF-7 breast cancer cells.
Collapse
Affiliation(s)
- Y Y Liu
- John Wayne Cancer Institute at Saint John's Health Center, Santa Monica, California 90404, USA
| | | | | | | |
Collapse
|
40
|
Robbins SM, Hollenberg MD. Chapter 11 Plasma Membrane-Localized Signal Transduction. CURRENT TOPICS IN MEMBRANES 1999. [DOI: 10.1016/s0070-2161(08)61049-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
41
|
Basu S, Bayoumy S, Zhang Y, Lozano J, Kolesnick R. BAD enables ceramide to signal apoptosis via Ras and Raf-1. J Biol Chem 1998; 273:30419-26. [PMID: 9804808 DOI: 10.1074/jbc.273.46.30419] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prior investigations document that proliferative signaling cascades, under some circumstances, initiate apoptosis, although mechanisms that dictate the final outcome are largely unknown. In COS-7 cells, ceramide signals Raf-1 activation through Ras (Zhang, Y., Yao, B., Delikat, S., Bayoumy, S., Lin, X. H., Basu, S., McGinley, M., Chan-Hui, P. Y., Lichenstein, H., and Kolesnick, R. (1997) Cell 89, 63-72), but not apoptosis. However, expression of small amounts of the pro-apoptotic Bcl-2 family member, BAD, conferred ceramide-induced apoptosis onto COS-7 cells. Ceramide signaled apoptosis in BAD-expressing cells by a pathway involving sequentially kinase suppressor of Ras (KSR)/ceramide-activated protein kinase, Ras, c-Raf-1, and MEK1. Downstream, this pathway linked to BAD dephosphorylation at serine 136 by prolonged inactivation of Akt/PKB. Further, mutation of BAD at serine 136 abrogated ceramide signaling of apoptosis. The present study indicates that when ceramide signals through the Ras/Raf cascade, the availability of a single target, BAD, may dictate an apoptotic outcome.
Collapse
Affiliation(s)
- S Basu
- Laboratory of Signal Transduction, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
| | | | | | | | | |
Collapse
|
42
|
Escargueil-Blanc I, Andrieu-Abadie N, Caspar-Bauguil S, Brossmer R, Levade T, Nègre-Salvayre A, Salvayre R. Apoptosis and activation of the sphingomyelin-ceramide pathway induced by oxidized low density lipoproteins are not causally related in ECV-304 endothelial cells. J Biol Chem 1998; 273:27389-95. [PMID: 9765267 DOI: 10.1074/jbc.273.42.27389] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Oxidized low density lipoproteins (oxLDL) are thought to play a central role in the development of atherosclerosis. Toxic concentrations of mildly oxidized LDL elicit massive apoptosis of endothelial cells (Escargueil-Blanc, I., Meilhac, O., Pieraggi, M. T. , Arnal J. F., Salvayre, R., Nègre-Salvayre, A. (1997) Arterioscler. Thromb. Vasc. Biol. 17, 331-339). Since the lipid mediator ceramide emerged as a potent inducer of apoptosis, we aimed at investigating the occurrence of ceramide formation and its potential role in oxLDL-induced apoptosis. In ECV-304 endothelial cells, toxic concentrations of oxLDL triggered an early activation of the sphingomyelin-ceramide pathway, as shown by both sphingomyelin hydrolysis and ceramide formation. N-Tosyl-L-phenylalanyl chloromethyl ketone (TPCK) and dichloroisocoumarin (DCIC), two serine-protease inhibitors (serpins), blocked the oxLDL-induced ceramide generation but, unexpectedly, did not inhibit the oxLDL-induced apoptosis. Conversely, treatment of endothelial cells by bacterial sphingomyelinase, under conditions effectively generating ceramide, did not induce apoptosis. In contrast, short-chain permeant C2- and C6-ceramides elicited apoptosis of ECV-304. However, the mechanisms of apoptosis triggered by C2-ceramide and by oxLDL were (at least in part) different, because C2-ceramide-induced apoptosis was calcium-independent, whereas oxLDL-induced apoptosis was calcium-dependent. In conclusion, it is suggested that oxLDL-induced apoptosis is calcium-dependent but independent of the activation of the sphingomyelin-ceramide pathway and that the toxic effect of short chain permeant ceramides is calcium-independent and does not mimic the effect of natural ceramides induced by oxLDL.
Collapse
Affiliation(s)
- I Escargueil-Blanc
- INSERM U-466 and the Biochemistry Department, Institut Louis Bugnard, CHU Rangueil, 31054 Toulouse Cedex, France
| | | | | | | | | | | | | |
Collapse
|
43
|
Rizzieri KE, Hannun YA. Sphingolipid metabolism, apoptosis and resistance to cytotoxic agents: can we interfere? Drug Resist Updat 1998; 1:359-76. [PMID: 17092818 DOI: 10.1016/s1368-7646(98)80012-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/1998] [Revised: 10/05/1998] [Accepted: 10/12/1998] [Indexed: 11/30/2022]
Abstract
Sphingolipid metabolism assumes a key role in the complex mechanisms regulating cellular stress responses to environmental stressors, including cytotoxic agents. The sphingolipid metabolic pathways, therefore, are promising sources of anticancer therapeutic strategies. Several sphingolipid metabolites have recently been shown to have bioactivity, and their individual contributions to the regulatory pathways that govern cell growth are currently being established in mammalian cells and yeast. The Sphingomyelin (SM) cycle represents a novel antiproliferative, sphingolipid-mediated signal transduction pathway that regulates cell cycle arrest, differentiation, and apoptosis in response to growth factor deprivation, cytokines, ionizing radiation, heat, and chemotherapy. Ceramide, the putative second messenger of the SM cycle, has been proposed as a molecular sensor of injury and assumes a fundamental role in the cellular stress response. This review will discuss sphingolipid metabolism within the context of the cellular stress response, the contribution of sphingolipids to chemotherapy-mediated apoptosis, and suggest novel sphingolipid-based strategies in the treatment of malignant disease.
Collapse
Affiliation(s)
- K E Rizzieri
- Department of Biochemistry, Medical University of South Carolina, Charleston, SC 29425, USA
| | | |
Collapse
|