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Yuniartha R, Arfian N, Setyaningsih WAW, Kencana SMS, Sari DCR, Sari DCR. Accelerated Senescence and Apoptosis in the Rat Liver during the Progression of Diabetic Complications. Malays J Med Sci 2022; 29:46-59. [PMID: 36818894 PMCID: PMC9910368 DOI: 10.21315/mjms2022.29.6.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/25/2022] [Indexed: 12/25/2022] Open
Abstract
Background Chronic hyperglycaemia of diabetes causes long-term damage and impaired function of multiple organs. However, the pathological changes in the liver following long-term diabetes remain unclear. This study aimed to determine the pathological complications of long-term diabetes in the rat liver. Methods Intraperitoneal injection of streptozotocin (STZ) was used to induce diabetes in rats at a single dose (60 mg/kg body weight [BW]). Rats were euthanised at 1 month (DM1 group), 2 months (DM2 group) and 4 months (DM4 group) following diabetes induction with six rats in each group. Immunohistochemistry was performed against SOD1, CD68, p53 and p16 antibodies. Messenger RNA (mRNA) expressions of SOD1, SOD2, GPx, CD68, p53, p21 and caspase-3 genes were measured by reverse transcription-polymerase chain reaction. Results Hepatic p53 mRNA expression was significantly higher in DM1, DM2 and DM4 groups compared to the control group. The p21 and caspase-3 mRNA expressions were significantly upregulated in the DM2 and DM4 groups. The p16-positive cells were obviously increased, particularly in the DM4 group. Bivariate correlation analysis showed mRNA expressions of p21 and caspase-3 genes were positively correlated with the p53 gene. Conclusion Diabetic rats exhibited increased apoptosis and senescence in the liver following a longer period of hyperglycaemia.
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C1orf61 promotes hepatocellular carcinoma metastasis and increases the therapeutic response to sorafenib. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119048. [PMID: 33915231 DOI: 10.1016/j.bbamcr.2021.119048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 12/12/2022]
Abstract
C1orf61 is a specific transcriptional activator that is highly up-regulated during weeks 4-9 of human embryogenesis, the period in which most organs develop. We have previously demonstrated that C1orf61 acts as a tumor activator in human hepatocellular carcinoma (HCC) tumorigenesis and metastasis. However, the underlying molecular mechanisms of tumor initiation and progression in HCC remain obscure. In this study, we demonstrated that the pattern of C1orf61 expression was closely correlated with metastasis in liver cancer cells. Gene expression profiling analysis indicated that C1orf61 regulated diverse genes related to cell growth, migration, invasion and epithelial-mesenchymal transition (EMT). Results showed that C1orf61 promotes hepatocellular carcinoma metastasis by inducing cellular EMT in vivo and in vitro. Moreover, C1orf61-induced cellular EMT and migration are involved in the activation of the STAT3 and Akt cascade pathways. In addition, C1orf61 expression improved the efficacy of the anticancer therapy sorafenib in HCC patients. For the first time, we report a regulatory pathway by which C1orf61 promoted cancer cell metastasis and regulated the therapeutic response to sorafenib. These findings increased our understanding of the molecular events that regulate metastasis and treatment in HCC.
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Kuang Y, Kang J, Li H, Liu B, Zhao X, Li L, Jin X, Li Q. Multiple functions of p21 in cancer radiotherapy. J Cancer Res Clin Oncol 2021; 147:987-1006. [PMID: 33547489 DOI: 10.1007/s00432-021-03529-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/10/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Greater than half of cancer patients experience radiation therapy, for both radical and palliative objectives. It is well known that researches on radiation response mechanisms are conducive to improve the efficacy of cancer radiotherapy. p21 was initially identified as a widespread inhibitor of cyclin-dependent kinases, transcriptionally modulated by p53 and a marker of cellular senescence. It was once considered that p21 acts as a tumour suppressor mainly to restrain cell cycle progression, thereby resulting in growth suppression. With the deepening researches on p21, p21 has been found to regulate radiation responses via participating in multiple cellular processes, including cell cycle arrest, apoptosis, DNA repair, senescence and autophagy. Hence, a comprehensive summary of the p21's functions in radiation response will provide a new perspective for radiotherapy against cancer. METHODS We summarize the recent pertinent literature from various electronic databases, including PubMed and analyzed several datasets from Gene Expression Omnibus database. This review discusses how p21 influences the effect of cancer radiotherapy via involving in multiple signaling pathways and expounds the feasibility, barrier and risks of using p21 as a biomarker as well as a therapeutic target of radiotherapy. CONCLUSION p21's complicated and important functions in cancer radiotherapy make it a promising therapeutic target. Besides, more thorough insights of p21 are needed to make it a safe therapeutic target.
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Affiliation(s)
- Yanbei Kuang
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, Gansu, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, 730000, Gansu, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jian Kang
- College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Hongbin Li
- School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050, China
| | - Bingtao Liu
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, Gansu, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, 730000, Gansu, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xueshan Zhao
- The First Hospital of Lanzhou University, Lanzhou, 730000, China
| | - Linying Li
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, Gansu, China
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, 730000, Gansu, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaodong Jin
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, Gansu, China.
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, 730000, Gansu, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Qiang Li
- Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou, 730000, Gansu, China.
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou, 730000, Gansu, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Engin A. Bile Acid Toxicity and Protein Kinases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:229-258. [PMID: 33539018 DOI: 10.1007/978-3-030-49844-3_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
If the bile acids reach to pathological concentrations due to cholestasis, accumulation of hydrophobic bile acids within the hepatocyte may result in cell death. Thus, hydrophobic bile acids induce apoptosis in hepatocytes, while hydrophilic bile acids increase intracellular adenosine 3',5'-monophosphate (cAMP) levels and activate mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways to protect hepatocytes from apoptosis.Two apoptotic pathways have been described in bile acids-induced death. Both are controlled by multiple protein kinase signaling pathways. In mitochondria-controlled pathway, caspase-8 is activated with death domain-independent manner, whereas, Fas-dependent classical pathway involves ligand-independent oligomerization of Fas.Hydrophobic bile acids dose-dependently upregulate the inflammatory response by further stimulating production of inflammatory cytokines. Death receptor-mediated apoptosis is regulated at the cell surface by the receptor expression, at the death-inducing signaling complex (DISC) by expression of procaspase-8, the death receptors Fas-associated death domain (FADD), and cellular FADD-like interleukin 1-beta (IL-1β)-converting enzyme (FLICE) inhibitory protein (cFLIP). Bile acids prevent cFLIP recruitment to the DISC and thereby enhance initiator caspase activation and lead to cholestatic apoptosis. At mitochondria, the expression of B-cell leukemia/lymphoma-2 (Bcl-2) family proteins contribute to apoptosis by regulating mitochondrial cytochrome c release via Bcl-2, Bcl-2 homology 3 (BH3) interacting domain death agonist (Bid), or Bcl-2 associated protein x (Bax). Fas receptor CD95 activation by hydrophobic bile acids is initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) signaling. However, activation of necroptosis by ligands of death receptors requires the kinase activity of receptor interacting protein1 (RIP1), which mediates the activation of RIP3 and mixed lineage kinase domain-like protein (MLKL). In this chapter, mainly the effect of protein kinases signal transduction on the mechanisms of hydrophobic bile acids-induced inflammation, apoptosis, necroptosis and necrosis are discussed.
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Affiliation(s)
- Atilla Engin
- Department of General Surgery, Faculty of Medicine, Gazi University, Ankara, Turkey.
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Dongoran RA, Wang KH, Lin TJ, Yuan TC, Liu CH. Anti-Proliferative Effect of Statins Is Mediated by DNMT1 Inhibition and p21 Expression in OSCC Cells. Cancers (Basel) 2020; 12:E2084. [PMID: 32731382 PMCID: PMC7463937 DOI: 10.3390/cancers12082084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Statins, also known as HMG-CoA reductase inhibitors, are a class of cholesterol-lowering drugs and their anti-cancer effects have been studied in different types of malignant diseases. In the present study, we investigated the anti-proliferative effects of statins, including cerivastatin and simvastatin, on oral squamous cell carcinoma (OSCC) cells. Our data showed that statins inhibited the proliferation of three OSCC cell lines in a dose-dependent manner and this growth inhibition was confirmed through G0/G1 cell cycle arrest. Accordingly, we found the upregulation of p21 and downregulation of cyclin-dependent kinases, including CDK2, CDK4, and CDK6, in the statin-treated cells. Importantly, we clearly showed that statins were able to inhibit the expression of DNA methyltransferase 1 (DNMT1) and further promote the expression of p21. Taken together, our data demonstrated that the anti-proliferative effect of statins is mediated by suppressing DNMT1 expression, thus promoting p21 expression and leading to G0/G1 cell cycle arrest in OSCC cells.
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Affiliation(s)
- Rachmad Anres Dongoran
- Ph.D. Program in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; (R.A.D.); (T.-J.L.)
- Indonesian Food and Drug Authority (Indonesian FDA), Jakarta 10560, Indonesia
| | - Kai-Hung Wang
- Department of Medical Research, Tzu Chi Hospital, Hualien 97004, Taiwan;
| | - Tsung-Jen Lin
- Ph.D. Program in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; (R.A.D.); (T.-J.L.)
| | - Ta-Chun Yuan
- Department of Life Science, College of Science and Engineering, National Dong Hwa University, Hualien 97401, Taiwan
| | - Chin-Hung Liu
- Ph.D. Program in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan; (R.A.D.); (T.-J.L.)
- Department of Pharmacology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan
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The Cell-Cycle Regulatory Protein p21 CIP1/WAF1 Is Required for Cytolethal Distending Toxin (Cdt)-Induced Apoptosis. Pathogens 2020; 9:pathogens9010038. [PMID: 31906446 PMCID: PMC7168616 DOI: 10.3390/pathogens9010038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/22/2019] [Accepted: 12/28/2019] [Indexed: 12/27/2022] Open
Abstract
The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21CIP1/WAF1 in lymphoid cell lines, Jurkat and MyLa, and in primary human lymphocytes. These increases were dependent upon CdtB’s ability to function as a phosphatidylinositol (PI) 3,4,5-triphosphate (PIP3) phosphatase. It is noteworthy that Cdt-induced increases in the levels of p21CIP1/WAF1 were accompanied by a significant decline in the levels of phosphorylated p21CIP1/WAF1. The significance of Cdt-induced p21CIP1/WAF1 increase was assessed by preventing these changes with a two-pronged approach; pre-incubation with the novel p21CIP1/WAF1 inhibitor, UC2288, and development of a p21CIP1/WAF1-deficient cell line (Jurkatp21−) using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 gene editing. UC2288 blocked toxin-induced increases in p21CIP1/WAF1, and JurkatWT cells treated with this inhibitor exhibited reduced susceptibility to Cdt-induced apoptosis. Likewise, Jurkatp21− cells failed to undergo toxin-induced apoptosis. The linkage between Cdt, p21CIP1/WAF1, and apoptosis was further established by demonstrating that Cdt-induced increases in levels of the pro-apoptotic proteins Bid, Bax, and Bak were dependent upon p21CIP1/WAF1 as these changes were not observed in Jurkatp21− cells. Finally, we determined that the p21CIP1/WAF1 increases were dependent upon toxin-induced increases in the level and activity of the chaperone heat shock protein (HSP) 90. We propose that p21CIP1/WAF1 plays a key pro-apoptotic role in mediating Cdt-induced toxicity.
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Weis KE, Raetzman LT. Genistein inhibits proliferation and induces senescence in neonatal mouse pituitary gland explant cultures. Toxicology 2019; 427:152306. [PMID: 31593742 DOI: 10.1016/j.tox.2019.152306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/26/2019] [Accepted: 10/02/2019] [Indexed: 12/27/2022]
Abstract
Genistein is an isoflavone abundant in soybean and infants are exposed to high levels of genistein in soy-based formula. It is known that genistein mediates estrogen receptor (ER) signaling, and exposure during neonatal development could cause acute and long term endocrine effects. We assayed genistein's impact on the neonatal mouse pituitary gland because it is an endocrine signaling hub and is sensitive to endocrine disruption during critical periods. Pituitary explant cultures, which actively proliferate and differentiate, were exposed to 0.06 μM-36 μM genistein and assayed for mRNA and protein changes. Genistein induced mRNA expression of the ERα regulated gene, Cckar, to the same magnitude as estradiol (E2) but with less potency. Interestingly, 36 μM genistein strongly inhibited pituitary proliferation, measured by a reduction in mKi67 mRNA and phospho-Histone H3 immunostaining. Examining cell cycle dynamics, we found that 36 μM genistein decreased Ccnb1 (Cyclin B1) mRNA; while mRNA for the cyclin dependent kinase inhibitor Cdkn1a (p21) was upregulated, correlated with an apparent increase in p21 immunostained cells. Strikingly, we observed a robust onset of cellular senescence, permanent cell cycle exit, in 36 μM genistein treated pituitaries by increased senescence activated β-galactosidase staining. We also found that 36 μM genistein decreased Bcl2 mRNA levels, a gene protective against apoptosis. Taken together these data suggest that genistein exposure during the neonatal period could initiate senescence and halt proliferation during a time when the proper numbers of endocrine cells are being established for mature gland function.
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Affiliation(s)
- Karen E Weis
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois, 61801, USA
| | - Lori T Raetzman
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois, 61801, USA.
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Al Bitar S, Gali-Muhtasib H. The Role of the Cyclin Dependent Kinase Inhibitor p21 cip1/waf1 in Targeting Cancer: Molecular Mechanisms and Novel Therapeutics. Cancers (Basel) 2019; 11:cancers11101475. [PMID: 31575057 PMCID: PMC6826572 DOI: 10.3390/cancers11101475] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 12/15/2022] Open
Abstract
p21cip1/waf1 mediates various biological activities by sensing and responding to multiple stimuli, via p53-dependent and independent pathways. p21 is known to act as a tumor suppressor mainly by inhibiting cell cycle progression and allowing DNA repair. Significant advances have been made in elucidating the potential role of p21 in promoting tumorigenesis. Here, we discuss the involvement of p21 in multiple signaling pathways, its dual role in cancer, and the importance of understanding its paradoxical functions for effectively designing therapeutic strategies that could selectively inhibit its oncogenic activities, override resistance to therapy and yet preserve its tumor suppressive functions.
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Affiliation(s)
- Samar Al Bitar
- Department of Biology, and Center for Drug Discovery, American University of Beirut, Beirut 1103, Lebanon.
| | - Hala Gali-Muhtasib
- Department of Biology, and Center for Drug Discovery, American University of Beirut, Beirut 1103, Lebanon.
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Rizzo F, Coffman JA, Arnone MI. An Elk transcription factor is required for Runx-dependent survival signaling in the sea urchin embryo. Dev Biol 2016; 416:173-186. [PMID: 27235147 DOI: 10.1016/j.ydbio.2016.05.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/23/2016] [Accepted: 05/23/2016] [Indexed: 12/20/2022]
Abstract
Elk proteins are Ets family transcription factors that regulate cell proliferation, survival, and differentiation in response to ERK (extracellular-signal regulated kinase)-mediated phosphorylation. Here we report the embryonic expression and function of Sp-Elk, the single Elk gene of the sea urchin Strongylocentrotus purpuratus. Sp-Elk is zygotically expressed throughout the embryo beginning at late cleavage stage, with peak expression occurring at blastula stage. Morpholino antisense-mediated knockdown of Sp-Elk causes blastula-stage developmental arrest and embryo disintegration due to apoptosis, a phenotype that is rescued by wild-type Elk mRNA. Development is also rescued by Elk mRNA encoding a serine to aspartic acid substitution (S402D) that mimics ERK-mediated phosphorylation of a conserved site that enhances DNA binding, but not by Elk mRNA encoding an alanine substitution at the same site (S402A). This demonstrates both that the apoptotic phenotype of the morphants is specifically caused by Elk depletion, and that phosphorylation of serine 402 of Sp-Elk is critical for its anti-apoptotic function. Knockdown of Sp-Elk results in under-expression of several regulatory genes involved in cell fate specification, cell cycle control, and survival signaling, including the transcriptional regulator Sp-Runt-1 and its target Sp-PKC1, both of which were shown previously to be required for cell survival during embryogenesis. Both Sp-Runt-1 and Sp-PKC1 have sequences upstream of their transcription start sites that specifically bind Sp-Elk. These results indicate that Sp-Elk is the signal-dependent activator of a feed-forward gene regulatory circuit, consisting also of Sp-Runt-1 and Sp-PKC1, which actively suppresses apoptosis in the early embryo.
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Affiliation(s)
- Francesca Rizzo
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli 80121, Italy
| | | | - Maria Ina Arnone
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli 80121, Italy.
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10
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GUO HUA, LI YANG, GU JUNLIAN, WANG YUE, LIU LIANQIN, ZHANG PING, LIU YANAN. Effect of vascular endothelial growth factor siRNA and wild-type p53 co-expressing plasmid in MDA-MB-231 cells. Mol Med Rep 2015; 13:461-8. [DOI: 10.3892/mmr.2015.4571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 09/22/2015] [Indexed: 11/05/2022] Open
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11
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Humbert L, Ghozlan M, Canaff L, Tian J, Lebrun JJ. The leukemia inhibitory factor (LIF) and p21 mediate the TGFβ tumor suppressive effects in human cutaneous melanoma. BMC Cancer 2015; 15:200. [PMID: 25885043 PMCID: PMC4389797 DOI: 10.1186/s12885-015-1177-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/06/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Cutaneous melanoma is the most lethal skin cancer and its incidence in developed countries has dramatically increased over the past decades. Localized tumors are easily treated by surgery, but advanced melanomas lack efficient treatment and are associated with very poor outcomes. Thus, understanding the processes underlying melanoma development and progression is critical. The Transforming Growth Factor beta (TGFβ) acts as a potent tumor suppressor in human melanoma, by inhibiting cell growth and preventing cellular migration and invasion. METHODS In this study, we aimed at elucidating the molecular mechanisms underlying TGFβ-mediated tumor suppression. Human cutaneous melanoma cell lines, derived from different patients, were used to assess for cell cycle analysis, apoptosis/caspase activity and cell migration. Techniques involved immunoblotting, immunohistochemistry, real time PCR and luciferase reporter assays. RESULTS We found the leukemia inhibitory factor (LIF) to be strongly up-regulated by TGFβ in melanoma cells, defining LIF as a novel TGFβ downstream target gene in cutaneous melanoma. Interestingly, we also showed that TGFβ-mediated LIF expression is required for TGFβ-induced cell cycle arrest and caspase-mediated apoptosis, as well as for TGFβ-mediated inhibition of cell migration. Moreover, we found that TGFβ-mediated LIF expression leads to activation of transcription of the cell cycle inhibitor p21 in a STAT3-dependent manner, and further showed that p21 is required for TGFβ/LIF-mediated cell cycle arrest and TGFβ-induced gene activation of several pro-apoptotic genes. CONCLUSIONS Together, our results define the LIF/p21 signaling cascade as a novel tumor suppressive-like pathway in melanoma, acting downstream of TGFβ to regulate cell cycle arrest and cell death, further highlight new potential therapeutic strategies for the treatment of cutaneous melanoma.
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Affiliation(s)
- Laure Humbert
- Division of Medical Oncology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
| | - Mostafa Ghozlan
- Division of Medical Oncology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
| | - Lucie Canaff
- Division of Medical Oncology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
| | - Jun Tian
- Division of Medical Oncology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
| | - Jean-Jacques Lebrun
- Division of Medical Oncology, Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
- Department of Medicine, Royal Victoria Hospital, Suite H7.66, 687 Pine Avenue West, H3A 1A1, Montreal, QC, Canada.
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Abstract
Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans.
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13
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Kang S, Kim JB, Heo TH, Kim SJ. Cell cycle arrest in Batten disease lymphoblast cells. Gene 2013; 519:245-50. [PMID: 23458879 DOI: 10.1016/j.gene.2013.02.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/02/2013] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
Batten disease is an inherited neurodegenerative disorder caused by a CLN3 gene mutation. Batten disease is characterized by blindness, seizures, cognitive decline, and early death. Although apoptotic cell death is one of the pathological hallmarks of Batten disease, little is known about the regulatory mechanism of apoptosis in this disease. Since the CLN3 gene is suggested to be involved in the cell cycle in a yeast model, we investigated the cell cycle profile and its regulatory factors in lymphoblast cells from Batten disease patients. We found G1/G0 cell cycle arrest in Batten disease cells, with overexpression of p21, sphingosine, glucosylceramide, and sulfatide as possible cell cycle regulators.
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Affiliation(s)
- Sunyang Kang
- Department of Biotechnology, Hoseo University, 165 Baebang, Asan, Chungnam, Republic of Korea
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Bashash D, Ghaffari SH, Zaker F, Hezave K, Kazerani M, Ghavamzadeh A, Alimoghaddam K, Mosavi SA, Gharehbaghian A, Vossough P. Direct short-term cytotoxic effects of BIBR 1532 on acute promyelocytic leukemia cells through induction of p21 coupled with downregulation of c-Myc and hTERT transcription. Cancer Invest 2012; 30:57-64. [PMID: 22236190 DOI: 10.3109/07357907.2011.629378] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Acute promyelocytic leukemia (APL) is characterized by specific t(15;17), distinct morphologic picture, and clinical coagulopathy that contribute to the morbidity and mortality of the disease. This study aims to investigate the effects of antitelomerase compound BIBR1532 on APL cells (NB4). BIBR 1532 exerts a direct short-term growth suppressive effect in a concentration-dependent manner probably through downregulation of c-Myc and hTERT expression. Our results also suggest that induction of p21 and subsequent disturbance of Bax/Bcl-2 balanced ratio as well as decreased telomerase activity may be rational mechanisms for the potent/direct short-term cytotoxicity of high doses of BIBR1532 against NB4 cells.
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Affiliation(s)
- D Bashash
- Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences
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15
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Huang WY, Yang PM, Chang YF, Marquez VE, Chen CC. Methotrexate induces apoptosis through p53/p21-dependent pathway and increases E-cadherin expression through downregulation of HDAC/EZH2. Biochem Pharmacol 2010; 81:510-7. [PMID: 21114963 DOI: 10.1016/j.bcp.2010.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/19/2010] [Accepted: 11/22/2010] [Indexed: 01/22/2023]
Abstract
Methotrexate (MTX) is a dihydrofolate reductase (DHFR) inhibitor widely used as an anticancer drug in different kinds of human cancers. Here we investigated the anti-tumor mechanism of MTX against non-small cell lung cancer (NSCLC) A549 cells. MTX not only inhibited in vitro cell growth via induction of apoptosis, but also inhibited tumor formation in animal xenograft model. RNase protection assay (RPA) and RT-PCR demonstrated its induction of p53 target genes including DR5, p21, Puma and Noxa. Moreover, MTX promoted p53 phosphorylation at Ser15 and acetylaion at Lys373/382, which increase its stability and expression. The apoptosis and inhibition of cell viability induced by MTX were dependent on p53 and, partially, on p21. In addition, MTX also increased E-cadherin expression through inhibition of histone deacetylase (HDAC) activity and downregulation of polycomb group protein enhancer of zeste homologue 2 (EZH2). Therefore, the anticancer mechanism of MTX acts through initiation of p53-dependent apoptosis and restoration of E-cadherin expression by downregulation of HDAC/EZH2.
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Affiliation(s)
- Wen-Yu Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei 10018, Taiwan
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16
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Inhibition of Autophagy Enhances Anticancer Effects of Atorvastatin in Digestive Malignancies. Cancer Res 2010; 70:7699-709. [DOI: 10.1158/0008-5472.can-10-1626] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Amaral JD, Castro RE, Steer CJ, Rodrigues CMP. p53 and the regulation of hepatocyte apoptosis: implications for disease pathogenesis. Trends Mol Med 2009; 15:531-41. [PMID: 19822456 DOI: 10.1016/j.molmed.2009.09.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 09/04/2009] [Accepted: 09/04/2009] [Indexed: 01/06/2023]
Abstract
The interplay between p53 and apoptosis in diseases such as cancer, neurodegeneration, ischemia and atherosclerosis underscores the need to understand the complexity of p53 networks. Here, we highlight recent studies of p53-induced apoptosis in human diseases, with a focus on the modulation of liver cell apoptosis. In addition, recent work has provided new insights into mechanisms underlying the antiapoptotic functions of the endogenous bile acid ursodeoxycholic acid (UDCA), suggesting that the finely tuned, complex control of p53 by Mdm2 is a key step in the UDCA modulation of deregulated, p53-triggered apoptosis. The effect of targeting cell death signaling proteins has been established in preclinical models of human diseases. Finally, we review recent therapeutic strategies and clinical applications of targeted agents, with a particular emphasis on the potential use of UDCA.
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Affiliation(s)
- Joana D Amaral
- Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
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18
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19
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Abstract
The cyclin-dependent kinase inhibitor p21(WAF1/CIP1) is a key mediator of p53-dependent cell cycle arrest and may play the role of a tumor suppressor in cancer. However, it has been shown that p21 may also act as an oncogene, because it inhibits apoptosis and may promote cell proliferation in some tumors. These data point out to "antagonistic duality" of p21, because it possesses anticancer and procancer properties at the same time. New data suggest that more and more proteins also may play contradictory roles in cancer thus challenging current paradigm of established oncogenes and tumor suppressors. (c) 2009 International Union of Biochemistry and Molecular Biology, Inc.
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Affiliation(s)
- Andrei L Gartel
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
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20
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Park MA, Zhang G, Norris J, Hylemon PB, Fisher PB, Grant S, Dent P. Regulation of autophagy by ceramide-CD95-PERK signaling. Autophagy 2008; 4:929-31. [PMID: 18719356 DOI: 10.4161/auto.6732] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The manuscripts by Park et al. and Zhang et al. were initially planned as studies to understand the regulation of cell survival in transformed cells treated with sorafenib and vorinostat, and in primary hepatocytes treated with a bile acid+MEK1/2 inhibitor. In both cell systems we discovered that the toxicity of sorafenib and vorinostat or bile acid+MEK1/2 inhibitor exposure depended on the generation of ceramide and the ligand-independent activation of the CD95 death receptor, with subsequent activation of pro-caspase 8. We noted, however, in these systems that, in parallel with death receptor-induced activation of the extrinsic pathway, CD95 signaling also promoted increased phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) and eIF2alpha, increased expression of ATG5, and increased processing of LC3 and vesicularization of a GFP-LC3 construct. The knockdown of ATG5 expression blocked GFP-LC3 vesicularization and enhanced cell killing. Thus ceramide-CD95 signaling promoted cell death via activation of pro-caspase 8 and cell survival via autophagy. PERK was shown to signal in a switch-hitting fashion; PERK promoted CD95-DISC formation and an eIF2alpha-dependent reduction in c-FLIP-s levels that were essential for cell killing to proceed, but in parallel it also promoted autophagy that was protective. The death receptor-induced apoptosis and autophagy occur proximal to the receptor rather than the mitochondrion, and the relative flow of death receptor signaling into either pathway may determine cell fate. Finally, death receptor induced apoptosis and autophagy could be potential targets for therapeutic intervention.
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Affiliation(s)
- Margaret A Park
- Department of Biochemistry, Virginia Commonwealth University, Richmond, Virginia 23298-0035, USA
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21
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Zhang G, Park MA, Mitchell C, Walker T, Hamed H, Studer E, Graf M, Rahmani M, Gupta S, Hylemon PB, Fisher PB, Grant S, Dent P. Multiple cyclin kinase inhibitors promote bile acid-induced apoptosis and autophagy in primary hepatocytes via p53-CD95-dependent signaling. J Biol Chem 2008; 283:24343-58. [PMID: 18614532 PMCID: PMC2528985 DOI: 10.1074/jbc.m803444200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/11/2008] [Indexed: 01/15/2023] Open
Abstract
Previously, using primary hepatocytes residing in early G1 phase, we demonstrated that expression of the cyclin-dependent kinase (CDK) inhibitor protein p21Cip-1/WAF1/mda6 (p21) enhanced the toxicity of deoxycholic acid (DCA) + MEK1/2 inhibitor. This study examined the mechanisms regulating this apoptotic process. Overexpression of p21 or p27(Kip-1) (p27) enhanced DCA + MEK1/2 inhibitor toxicity in primary hepatocytes that was dependent on expression of acidic sphingomyelinase and CD95. Overexpression of p21 suppressed MDM2, elevated p53 levels, and enhanced CD95, BAX, NOXA, and PUMA expression; knockdown of BAX/NOXA/PUMA reduced CDK inhibitor-stimulated cell killing. Parallel to cell death processes, overexpression of p21 or p27 profoundly enhanced DCA + MEK1/2 inhibitor-induced expression of ATG5 and GRP78/BiP and phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) and eIF2alpha, and it increased the numbers of vesicles containing a transfected LC3-GFP construct. Incubation of cells with 3-methyladenine or knockdown of ATG5 suppressed DCA + MEK1/2 inhibitor-induced LC3-GFP vesicularization and enhanced DCA + MEK1/2 inhibitor-induced toxicity. Expression of dominant negative PERK blocked DCA + MEK1/2 inhibitor-induced expression of ATG5, GRP78/BiP, and eIF2alpha phosphorylation and prevented LC3-GFP vesicularization. Knock-out or knockdown of p53 or CD95 abolished DCA + MEK1/2 inhibitor-induced PERK phosphorylation and prevented LC3-GFP vesicularization. Thus, CDK inhibitors suppress MDM2 levels and enhance p53 expression that facilitates bile acid-induced, ceramide-dependent CD95 activation to induce both apoptosis and autophagy in primary hepatocytes.
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Affiliation(s)
- Guo Zhang
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Margaret A. Park
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Clint Mitchell
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Teneille Walker
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Hossein Hamed
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Elaine Studer
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Martin Graf
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Mohamed Rahmani
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Seema Gupta
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Philip B. Hylemon
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Paul B. Fisher
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Steven Grant
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
| | - Paul Dent
- Departments of Biochemistry and
Molecular Biology,
Hematology/Oncology, Microbiology and
Immunology, Neurosurgery,
Human and Molecular Genetics, and
Institute for Molecular Medicine, Virginia
Commonwealth University, Richmond, Virginia 23298-0035
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22
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Nguyen A, Bouscarel B. Bile acids and signal transduction: role in glucose homeostasis. Cell Signal 2008; 20:2180-97. [PMID: 18634871 DOI: 10.1016/j.cellsig.2008.06.014] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 06/23/2008] [Indexed: 01/06/2023]
Abstract
Bile acids are mainly recognized for their role in dietary lipid absorption and cholesterol homeostasis. However, recent progress in bile acid research suggests that bile acids are important signaling molecules that play a role in glucose homeostasis. Among the various supporting evidence, several reports have demonstrated an improvement of the glycemic index of type 2 diabetic patients treated with diverse bile acid binding resins. Herein, we review the diverse interactions of bile acids with various signaling/response pathways, including calcium mobilization and protein kinase activation, membrane receptor-mediated responses, and nuclear receptor responses. Some of the effects of the bile acids are direct through the activation of specific receptors, i.e., TGR5, CAR, VDR, and FXR, while others imply modulation of the hormonal, growth factor and/or neuromediator responses, i.e., glucagon, EGF, and acetylcholine. We also discuss recent evidence implicating the interaction of bile acids with glucose homeostasis mechanisms, with the integration of our understanding of how the signaling mechanisms modulated by bile acid could regulate glucose metabolism.
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Affiliation(s)
- Amy Nguyen
- Department of Biochemistry and Molecular Biology, The George Washington University Medical Center, Washington, DC 20037, USA
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23
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Wang YD, Yang F, Chen WD, Huang X, Lai L, Forman BM, Huang W. Farnesoid X receptor protects liver cells from apoptosis induced by serum deprivation in vitro and fasting in vivo. Mol Endocrinol 2008; 22:1622-32. [PMID: 18436567 DOI: 10.1210/me.2007-0527] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The farnesoid X receptor (FXR) is a key metabolic regulator in the liver by maintaining the homeostasis of liver metabolites. Recent findings suggest that FXR may have a much broader function in liver physiology and pathology. In the present work, we identify a novel role of FXR in protecting liver cell from apoptosis induced by nutritional withdrawal including serum deprivation in vitro or starvation in vivo. Two FXR ligands, chenodeoxycholic acid (CDCA) and GW4064, rescued HepG2 cells from serum deprivation-induced apoptosis in a dose-dependent manner. This effect of FXR on apoptotic suppression was compromised when FXR was knocked down by short interfering RNA. Similarly, the effects of both CDCA and GW4064 were abolished after inhibition of the MAPK pathway by a specific inhibitor of MAPK kinase 1/2. Immunoblotting results indicated that FXR activation by CDCA and GW4064 induced ERK1/2 phosphorylation, which was attenuated by serum deprivation. In vivo, FXR(-/-) mice exhibited an exacerbated liver apoptosis and lower levels of phosphorylated-ERK1/2 compared to wild-type mice after starvation. In conclusion, our results suggest a novel role of FXR in modulating liver cell apoptosis.
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Affiliation(s)
- Yan-Dong Wang
- Department of Gene Regulation and Drug Discovery, Beckman Research Institute of City of Hope National Medical Center, Duarte, CA 91010, USA
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24
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Fujiwara K, Daido S, Yamamoto A, Kobayashi R, Yokoyama T, Aoki H, Iwado E, Shinojima N, Kondo Y, Kondo S. Pivotal Role of the Cyclin-dependent Kinase Inhibitor p21WAF1/CIP1 in Apoptosis and Autophagy. J Biol Chem 2008; 283:388-397. [DOI: 10.1074/jbc.m611043200] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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25
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Papeleu P, Wullaert A, Elaut G, Henkens T, Vinken M, Laus G, Tourwé D, Beyaert R, Rogiers V, Vanhaecke T. Inhibition of NF-kappaB activation by the histone deacetylase inhibitor 4-Me2N-BAVAH induces an early G1 cell cycle arrest in primary hepatocytes. Cell Prolif 2007; 40:640-55. [PMID: 17877607 PMCID: PMC6496027 DOI: 10.1111/j.1365-2184.2007.00466.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Benzoylaminoalkanohydroxamic acids, including 5-(4-dimethylaminobenzoyl)aminovaleric acid hydroxamide (4-Me(2)N-BAVAH), are structural analogues of Trichostatin A, a naturally occurring histone deacetylase inhibitor (HDACi). 4-Me(2)N-BAVAH has been shown to induce histone hyperacetylation and to inhibit proliferation in Friend erythroleukaemia cells in vitro. However, the molecular mechanisms have remained unidentified. MATERIALS AND METHODS In this study, we evaluated the effects of 4-Me(2)N-BAVAH on proliferation in non-malignant cells, namely epidermal growth factor-stimulated primary rat hepatocytes. RESULTS AND CONCLUSION We have found that 4-Me(2)N-BAVAH inhibits HDAC activity at non-cytotoxic concentrations and prevents cells from responding to the mitogenic stimuli of epidermal growth factor. This results in an early G(1) cell cycle arrest that is independent of p21 activity, but instead can be attributed to inhibition of cyclin D1 transcription through a mechanism involving inhibition of nuclear factor-kappaB activation. In addition, 4-Me(2)N-BAVAH delays the onset of spontaneous apoptosis in primary rat hepatocyte cultures as evidenced by down-regulation of the pro-apoptotic proteins Bid and Bax, and inhibition of caspase-3 activation.
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Affiliation(s)
- P Papeleu
- Department of Toxicology, Vrije Universiteit Brussel, Brussels, Belgium
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26
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Castro RE, Amaral JD, Solá S, Kren BT, Steer CJ, Rodrigues CMP. Differential regulation of cyclin D1 and cell death by bile acids in primary rat hepatocytes. Am J Physiol Gastrointest Liver Physiol 2007; 293:G327-34. [PMID: 17431217 DOI: 10.1152/ajpgi.00093.2007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ursodeoxycholic (UDCA) and tauroursodeoxycholic (TUDCA) acids modulate apoptosis and regulate cell-cycle effectors, including cyclin D1. In contrast, deoxycholic acid (DCA) induces cell death and cyclin D1. In this study, we explored the role of cyclin D1 in DCA-induced toxicity and further elucidated the antiapoptotic function of UDCA and TUDCA in primary rat hepatocytes. Cells were incubated with DCA and with or without UDCA or TUDCA for 8-30 h. In addition, hepatocytes were transfected with either an adenovirus expressing cyclin D1 or with a cyclin D1 reporter plasmid with or without bile acids. Finally, cells were cotransfected with short interfering RNA targeting p53. Unlike DCA, both UDCA and TUDCA reduced cyclin D1 expression and transcriptional activation, confirming our previous DNA microarray data. Furthermore, UDCA and TUDCA prevented DCA-induced cyclin D1 and cell death. Cyclin D1 overexpression increased DCA-induced Bax translocation, cytochrome c release, and apoptosis. However, UDCA and TUDCA were less efficient at decreasing cyclin D1 levels as well as DCA-induced changes with overexpression. Finally, after p53 silencing, the effects of cyclin D1 overexpression were almost completely abrogated, whereas UDCA and TUDCA cytoprotective potential was reestablished. In conclusion, cyclin D1 is a relevant player in modulating apoptosis by bile acids, in part through a p53-dependent mechanism.
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Affiliation(s)
- Rui E Castro
- Centro de Patogénese Molecular, Faculty of Pharmacy, University of Lisbon, Av. das Forças Armadas, 1600-083 Lisbon, Portugal
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27
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Fang Y, Studer E, Mitchell C, Grant S, Pandak WM, Hylemon PB, Dent P. Conjugated bile acids regulate hepatocyte glycogen synthase activity in vitro and in vivo via Galphai signaling. Mol Pharmacol 2007; 71:1122-8. [PMID: 17200418 DOI: 10.1124/mol.106.032060] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The regulation of glycogen synthase activity by bile acids in primary hepatocytes and in the intact liver was investigated. Bile acids (deoxycholic acid, DCA; taurocholic acid, TCA) activated AKT and glycogen synthase (GS) in primary rat hepatocytes. Incubation with a phosphatidyl inositol-3 kinase inhibitor or expression of dominant-negative AKT in primary rat hepatocytes abolished activation of AKT and GS by DCA and TCA. TCA, but not DCA, activated Galpha(i) proteins in primary rat hepatocytes. Treatment of cells with pertussis toxin or expression of dominant-negative Galpha(i) blocked TCA-induced activation of AKT and of GS but did not alter AKT or GS activation caused by DCA. TCA caused activation of AKT and GS in intact rat liver. Expression of dominant-negative Galpha(i) reduced TCA-induced activation of AKT and of GS in intact rat liver. Together, our findings demonstrate that bile acids are physiological regulators of glycogen synthase in rat liver and that conjugated bile acids use a Galpha(i)-coupled G protein-coupled receptor to regulate GS activity in vitro and in vivo.
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Affiliation(s)
- Youwen Fang
- Department of Biochemistry, Box 980035, Virginia Commonwealth University, Richmond VA 23298-0035, USA
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28
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Ocker M, Schneider-Stock R. Histone deacetylase inhibitors: signalling towards p21cip1/waf1. Int J Biochem Cell Biol 2007; 39:1367-74. [PMID: 17412634 DOI: 10.1016/j.biocel.2007.03.001] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 02/16/2007] [Accepted: 03/02/2007] [Indexed: 01/03/2023]
Abstract
Chromatin-modifying enzymes such as histone deacetylases (HDAC) facilitate a closed chromatin structure and hence transcriptional repression. HDAC are commonly affected in human cancer diseases. Thus, inhibition of HDAC represents a novel therapeutic approach. Several studies have shown that HDAC inhibitors strongly activate the expression of the cyclin-dependent kinase inhibitor p21(cip1/waf1) through (i) enhanced histone acetylation around the p21(cip1/waf1) promoter and (ii) the Sp1 sites on the p21(cip1/waf1) promoter releasing the repressor HDAC1 from its binding. p21(cip1/waf1) expression is regulated in a p53-dependent and p53-independent manner. The decision if p21(cip1/waf1) up-regulation results in cell cycle arrest or apoptosis, decides about the therapeutic efficacy of an anti-cancer treatment with HDAC inhibitors.
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Affiliation(s)
- Matthias Ocker
- Department of Medicine 1, University Hospital Erlangen, Erlangen, Germany.
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29
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Qiao L, Zhang H, Yu J, Francisco R, Dent P, Ebert MPA, Röcken C, Farrell G. Constitutive activation of NF-kappaB in human hepatocellular carcinoma: evidence of a cytoprotective role. Hum Gene Ther 2006; 17:280-90. [PMID: 16544977 DOI: 10.1089/hum.2006.17.280] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Activation of nuclear factor-kappaB (NF-kappaB) can promote or inhibit apoptosis. Oxidative stress is an important mechanism by which certain anticancer drugs kill cancer cells, and is also one of the mechanisms that activate NF-kappaB. We therefore examined hepatic expression of the NF-kappaB monomer p65 in human hepatocellular carcinoma (HCC) tissue samples from eight patients and compared it with their respective samples of surrounding liver tissues. We also studied the effect of NF-kappaB inhibition in human HCC cells exposed to oxidative stress, by infecting HuH7 cells with a recombinant adenovirus carrying mutant IkappaBalpha (mIkappaBalpha). Cultured HuH7 cells were infected with mIkappaBalpha or beta-galactosidase (beta-Gal) for 24 hr followed by treatment with increasing concentrations of H2O2. Cytotoxicity, NF-kappaB translocation, NF-kappaB DNA binding, cell proliferation, and apoptosis were determined. The monomer p65 was overexpressed in six of eight human HCC tissues. In HuH7 cells, introduction of mIkappaBalpha potently inhibited the translocation, activation, and DNA binding of NF- kappaB. In control (beta-Gal-infected) HuH7 cells, exposure to H2O2 produced a dose-dependent increase in apoptosis, regardless of NF-kappaB status. mIkappaBalpha-mediated inhibition of NF-kappaB activation sensitized HuH7 cells to H2O2-induced inhibition of cell growth, and further promoted cell death. Addition of H2O2 (200-500 microM) to control or mIkappaBalpha-infected HuH7 cells enhanced caspase-3 activity and cleavage. Adenovirus-mediated transfer of mIkappaBalpha potently inhibits NF-kappaB activity in HuH7 cells, and this enhances oxidative stress-induced cell killing.
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Affiliation(s)
- Liang Qiao
- Storr Liver Unit, Westmead Millennium Institute, University of Sydney at Westmead Hospital, Westmead, NSW 2145, Australia
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30
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Qiao L, Zhang H, Yu J, Francisco R, Dent P, Ebert MP, Rocke C, Farrell G. Constitutive Activation of NF-B in Human Hepatocellular Carcinoma: Evidence of a Cytoprotective Role. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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31
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Boncoeur E, Tabary O, Bonvin E, Muselet C, Fritah A, Lefait E, Redeuilh G, Clement A, Jacquot J, Henrion-Caude A. Oxidative stress response results in increased p21WAF1/CIP1 degradation in cystic fibrosis lung epithelial cells. Free Radic Biol Med 2006; 40:75-86. [PMID: 16337881 DOI: 10.1016/j.freeradbiomed.2005.08.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 07/27/2005] [Accepted: 08/15/2005] [Indexed: 12/31/2022]
Abstract
Lung epithelium in cystic fibrosis (CF) patients is characterized by structural damage and altered repair due to oxidative stress. To gain insight into the oxidative stress-related damage in CF, we studied the effects of hyperoxia in CF and normal lung epithelial cell lines. In response to a 95% O2 exposure, both cell lines exhibited increased reactive oxygen species. Unexpectedly, the cyclin-dependent kinase inhibitor p21WAF1/CIP1 protein was undetectable in CF cells under hyperoxia, contrasting with increased levels of p21WAF1/CIP1 in normal cells. In both cell lines, exposure to hyperoxia led to S-phase arrest. Apoptotic features including nuclear condensation, DNA laddering, Annexin V incorporation, and elevated caspase-3 activity were not readily observed in CF cells in contrast to normal cells. Interestingly, treatment of hyperoxia-exposed CF cells with two proteasome inhibitors, MG132 and lactacystin, restored p21WAF1/CIP1 protein and was associated with an increase of caspase-3 activity. Moreover, transfection of p21WAF1/CIP1 protein in CF cells led to increased caspase-3 activity and was associated with increased apoptotic cell death, specifically under hyperoxia. Taken together, our data suggest that modulating p21WAF1/CIP1 degradation may have the therapeutic potential of reducing lung epithelial damage related to oxidative stress in CF patients.
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Affiliation(s)
- Emilie Boncoeur
- Inserm U719, Université Pierre et Marie Curie, Hôpital Saint-Antoine, 184 rue du Fg St Antoine, Bâtiment Kourilsky, 75571 Paris Cedex 12, France
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32
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Gartel AL. The conflicting roles of the cdk inhibitor p21(CIP1/WAF1) in apoptosis. Leuk Res 2005; 29:1237-8. [PMID: 15946739 DOI: 10.1016/j.leukres.2005.04.023] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Accepted: 04/29/2005] [Indexed: 10/25/2022]
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33
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Papeleu P, Vanhaecke T, Elaut G, Vinken M, Henkens T, Snykers S, Rogiers V. Differential effects of histone deacetylase inhibitors in tumor and normal cells-what is the toxicological relevance? Crit Rev Toxicol 2005; 35:363-78. [PMID: 15989141 DOI: 10.1080/10408440590935639] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Histone deacetylase (HDAC) inhibitors target key steps of tumor development: They inhibit proliferation, induce differentiation and/or apoptosis, and exhibit potent antimetastatic and antiangiogenic properties in transformed cells in vitro and in vivo. Preliminary studies in animal models have revealed a relatively high tumor selectivity of HDAC inhibitors, strenghtening their promising potential in cancer chemotherapy. Until now, preclinical in vitro research has almost exclusively been performed in cancer cell lines and oncogene-transformed cells. However, as cell proliferation and apoptosis are essential for normal tissue and organ homeostasis, it is important to investigate how HDAC inhibitors influence the regulation of and interplay between proliferation, differentiation, and apoptosis in primary cells as well. This review highlights the discrepancies in molecular events triggered by trichostatin A, the reference compound of hydroxamic acid-containing HDAC inhibitors, in hepatoma cells and primary hepatocytes (which are key targets for drug-induced toxicity). The implications of these differential outcomes in both cell types are discussed with respect to both toxicology and drug development. In view of the future use of HDAC inhibitors as cytostatic drugs, it is highly recommended to include both tumor cells and their healthy counterparts in preclinical developmental studies. Screening the toxicological properties of compounds early in their development process, using a battery of different cell types, will enable researchers to discard those compounds bearing undesirable adverse activity before entering into expensive clinical trials. This will not only reduce the risk for harmful exposure of patients but also save time and money.
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Affiliation(s)
- Peggy Papeleu
- Department of Toxicology, Vrije Universiteit Brussel, Brussels, Belgium.
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Solá S, Castro RE, Kren BT, Steer CJ, Rodrigues CMP. Modulation of nuclear steroid receptors by ursodeoxycholic acid inhibits TGF-beta1-induced E2F-1/p53-mediated apoptosis of rat hepatocytes. Biochemistry 2004; 43:8429-38. [PMID: 15222754 DOI: 10.1021/bi049781x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recently shown that both ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) prevent transforming growth factor beta1 (TGF-beta1)-induced hepatocyte apoptosis by modulating the E2F-1/p53/Bax pathway. In addition, activation of glucocorticoid (GR) and mineralocorticoid receptors (MR) inhibits apoptosis in various systems. UDCA induces a ligand-independent activation of the GR, thus potentially regulating a number of targets. In this study, we investigated the role of GR and MR during TGF-beta1-induced hepatocyte apoptosis, and identified additional antiapoptotic targets for UDCA. Our results showed that in primary hepatocytes, TGF-beta1 induced 40-50% decreases in gr and mr mRNA expression (p < 0.01), together with up to 10-fold reductions in their protein levels (p < 0.01). Notably, pretreatment with UDCA resulted in a significant upregulation of nuclear steroid receptors (p < 0.05), which coincided with 2- and 3-fold increases in the level of GR and MR nuclear translocation, respectively, when compared with that of TGF-beta1 alone (p < 0.05). Similarly, TUDCA induced GR and MR nuclear translocations (p < 0.05) and markedly prevented MR protein changes associated with TGF-beta1 (p < 0.05) without affecting GR protein levels. Moreover, when interference RNA was used to inhibit GR and MR, UDCA no longer protected hepatocytes against TGF-beta1-induced apoptosis. In fact, the protective effect of UDCA in TGF-beta1-associated caspase activation decreased from 65 to <10% when GR or MR function was blocked. Finally, the TGF-beta1-induced E2F-1/Mdm-2/p53 apoptotic pathway, normally inhibited by UDCA, was not regulated by the bile acid after GR or MR silencing. These results demonstrate that UDCA protects against apoptosis through an additional pathway that involves nuclear receptors GR and MR as key factors. Further, the E2F-1/Mdm-2/p53 apoptotic pathway appears to be a prime target for UDCA-induced steroid receptor activation.
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Affiliation(s)
- Susana Solá
- Centro de Patogénese Molecular, Faculty of Pharmacy, University of Lisbon, Lisbon 1600-083, Portugal
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Chopin V, Slomianny C, Hondermarck H, Le Bourhis X. Synergistic induction of apoptosis in breast cancer cells by cotreatment with butyrate and TNF-alpha, TRAIL, or anti-Fas agonist antibody involves enhancement of death receptors' signaling and requires P21waf1. Exp Cell Res 2004; 298:560-73. [PMID: 15265702 DOI: 10.1016/j.yexcr.2004.04.038] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2003] [Revised: 03/22/2004] [Indexed: 10/26/2022]
Abstract
Inhibitors of histone deacetylase (HDAC) are considered as potential anticancer agents. We have previously demonstrated that an inhibitor of HDAC, sodium butyrate (NaB), induces apoptosis of breast cancer cells in a P53-independent and P21(waf1)-dependent manner. In this study, we showed that tumor necrosis factor-alpha (TNF-alpha), TNF-related apoptosis-inducing ligand (TRAIL), and anti-Fas agonist antibody potentiated NaB-induced growth inhibition through synergistic induction of apoptosis in breast cancer cell lines (MCF-7, T47-D, and BT-20). In MCF-7 cells, NaB increased the expression of death receptors; NaB alone or in combination with TNF-alpha, TRAIL, and anti-Fas agonist antibody increased the levels of Bid, tBid, and that of cytosolic cytochrome c. Synergistic induction of apoptosis was strongly inhibited by dominant-negative Fas-associated death domain (FADD) and inhibitors of caspases-8 and -9, indicating that potentiation of apoptosis involved key elements of death receptors' signaling pathways. Moreover, cotreatment of NaB and ligands of death receptors up-regulated the levels of P21(waf1) and that of proliferating cell nuclear antigen (PCNA) associated with P21(waf1). Transient transfections of p21(waf1) antisense or p21(waf1) deficient for its interaction with PCNA abolished synergistic induction of apoptosis. This suggested that potentiation of apoptosis by cotreatments required P21(waf1) and its interaction with PCNA. Since breast tumors contain rarely p21 mutations, our results may open interesting prospects in the fight against breast cancer.
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Affiliation(s)
- V Chopin
- Laboratoire de Biologie du Développement, UPRES-EA 1033, IFR-118, Université des Sciences et Technologies de Lille, Bâtiment SN3, 59655 Villeneuve d'Ascq Cedex, France
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Chopin V, Toillon RA, Jouy N, Le Bourhis X. P21(WAF1/CIP1) is dispensable for G1 arrest, but indispensable for apoptosis induced by sodium butyrate in MCF-7 breast cancer cells. Oncogene 2004; 23:21-9. [PMID: 14712207 DOI: 10.1038/sj.onc.1207020] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sodium butyrate (NaB) has been proposed as a potential anticancer agent. However, its mechanism of action is not totally elucidated. Here, we showed that NaB-induced cell cycle arrest and apoptosis were associated with an increase of P21(waf1/cip1) in MCF-7 breast cancer cells. This increase was more important in the nuclei, as revealed by immunofluorescence analysis. Transient transfections of MCF-7 cells with p21 deficient for interaction with CDK, but not with p21 deficient for interaction with PCNA (p21PCNA-), abrogated NaB-induced cell cycle arrest. This indicated that cell cycle blockage involved the interaction of P21(waf1/cip1) with CDK. However, P21(waf1/cip1) was dispensable, since p21 antisense did not modify cell cycle arrest. On the other hand, NaB-induced apoptosis was abolished by p21 antisense or p21PCNA-. In addition, NaB decreased PCNA levels, but increased the association of PCNA with P21(waf1/cip1). These results suggested that NaB-induced apoptosis required P21(waf1/cip1) and its interaction with PCNA.
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Affiliation(s)
- Valérie Chopin
- Equipe facteurs de croissance, Laboratoire de Biologie du Développement (UPRES 1033), IFR 118, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq Cedex 59655, France
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Higuchi H, Grambihler A, Canbay A, Bronk SF, Gores GJ. Bile acids up-regulate death receptor 5/TRAIL-receptor 2 expression via a c-Jun N-terminal kinase-dependent pathway involving Sp1. J Biol Chem 2003; 279:51-60. [PMID: 14561739 DOI: 10.1074/jbc.m309476200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bile acids up-regulate death receptor 5 (DR5)/TRAIL-receptor 2 (TRAIL-R2) expression thereby sensitizing hepatocytes to TRAIL-mediated apoptosis. However, the precise mechanism by which bile acids enhance DR5/TRAIL-R2 expression is unknown. Although several bile acids enhanced DR5/TRAIL-R2 expression, deoxycholic acid (DCA) was the most potent. DCA stimulated JNK activation and the JNK inhibitor SP600125 blocked DCA-induced DR5/TRAIL-R2 mRNA and protein expression. Reporter gene analysis identified a 5'-flanking region containing two Sp1 binding sites within the DR5/TRAIL-R2 promoter as bile acid responsive. Sp1 binding to one of the two sites was enhanced by DCA treatment as evaluated by electrophoretic mobility shift assays and chromatin immunoprecipitation studies. JNK inhibition with SP600125 also blocked binding of Sp1 to the DR5/TRAIL-R2 promoter. Finally, point mutations of the Sp1 binding site attenuated promoter activity. In conclusion, Sp1 is a bile acid-responsive transcription factor that mediates DR5/TRAIL-R2 gene expression downstream of JNK.
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Affiliation(s)
- Hajime Higuchi
- Division of Gastroenterology and Hepatology, Mayo Medical School, Clinic, and Foundation, Rochester, Minnesota 55905, USA
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Decker RH, Levin J, Kramer LB, Dai Y, Grant S. Enforced expression of the tumor suppressor p53 renders human leukemia cells (U937) more sensitive to 1-[beta-D-arabinofuranosyl]cytosine (ara-C)-induced apoptosis. Biochem Pharmacol 2003; 65:1997-2008. [PMID: 12787880 DOI: 10.1016/s0006-2952(03)00149-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effects of enforced expression of p53 on the sensitivity of p53(-/-) human monocytic leukemia cells (U937) to apoptosis following exposure to the S-phase-specific antimetabolite 1-[beta-D-arabinofuranosyl]cytosine (ara-C) were examined. Cells were stably transfected with a plasmid containing a chimeric DNA construct encoding a temperature-sensitive p53 variant (135(ala-->val)), which transactivates at 32 degrees but is non-functional at 37 degrees. A significant reduction in the S-phase population was observed in ptsp53 mutants incubated at 32 degrees. Nevertheless, while vector controls did not exhibit differential sensitivity to ara-C at 32 degrees versus 37 degrees, temperature-sensitive p53 mutants displayed a significant increase in apoptosis at the permissive temperature. This was not accompanied by increased ara-CTP formation, DNA incorporation of [3H]ara-C, or altered expression of Bcl-2 or Bax. Enhanced sensitivity was associated with increased mitochondrial injury (e.g. cytochrome c release), caspase activation, and loss of clonogenic survival. Significantly, ptsp53 cells synchronized in S phase were markedly more sensitive to ara-C-mediated mitochondrial injury and apoptosis at 32 degrees, indicating that wild-type p53 specifically enhances the susceptibility of this subpopulation to ara-C lethality. Consistent with these results, transient transfection of human wild-type p53 cDNA rendered parental U937 cells more sensitive to ara-C-mediated cell death. Collectively, these findings indicate that p53 expression renders S-phase U937 cells more susceptible to ara-C-mediated mitochondrial dysfunction, cytochrome c release, apoptosis, and loss of clonogenic survival without enhancing ara-C metabolism. Such findings raise the possibility that loss of functional p53 activity allows leukemia cells to circumvent ara-C lethality.
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Affiliation(s)
- Roy H Decker
- Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298, USA
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Qiao L, Han SI, Fang Y, Park JS, Gupta S, Gilfor D, Amorino G, Valerie K, Sealy L, Engelhardt JF, Grant S, Hylemon PB, Dent P. Bile acid regulation of C/EBPbeta, CREB, and c-Jun function, via the extracellular signal-regulated kinase and c-Jun NH2-terminal kinase pathways, modulates the apoptotic response of hepatocytes. Mol Cell Biol 2003; 23:3052-66. [PMID: 12697808 PMCID: PMC153195 DOI: 10.1128/mcb.23.9.3052-3066.2003] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2002] [Revised: 10/25/2002] [Accepted: 01/10/2003] [Indexed: 01/21/2023] Open
Abstract
Previously, we have demonstrated that deoxycholic acid (DCA)-induced signaling of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in primary hepatocytes is a protective response. In the present study, we examined the roles of the ERK and c-Jun NH(2)-terminal kinase (JNK) pathways, and downstream transcription factors, in the survival response of hepatocytes. DCA caused activation of the ERK1/2 and JNK1/2 pathways. Inhibition of either DCA-induced ERK1/2 or DCA-induced JNK1/2 signaling enhanced the apoptotic response of hepatocytes. Further analyses demonstrated that DCA-induced JNK2 signaling was cytoprotective whereas DCA-induced JNK1 signaling was cytotoxic. DCA-induced ERK1/2 activation was responsible for increased DNA binding of C/EBPbeta, CREB, and c-Jun/AP-1. Inhibition of C/EBPbeta, CREB, and c-Jun function promoted apoptosis following DCA treatment, and the level of apoptosis was further increased in the case of CREB and c-Jun, but not C/EBPbeta, by inhibition of MEK1/2. The combined loss of CREB and c-Jun function or of C/EBPbeta and c-Jun function enhanced DCA-induced apoptosis above the levels resulting from the loss of either factor individually; however, these effects were less than additive. Loss of c-Jun or CREB function correlated with increased expression of FAS death receptor and PUMA and decreased expression of c-FLIP-(L) and c-FLIP-(S), proteins previously implicated in the modulation of the cellular apoptotic response. Collectively, these data demonstrate that multiple DCA-induced signaling pathways and transcription factors control hepatocyte survival.
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Affiliation(s)
- Liang Qiao
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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