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Gupta-Saraf P, Miller CL. HIF-1α downregulation and apoptosis in hypoxic prostate tumor cells infected with oncolytic mammalian orthoreovirus. Oncotarget 2015; 5:561-74. [PMID: 24504474 PMCID: PMC3964229 DOI: 10.18632/oncotarget.1767] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hypoxia has emerged as one of the most important drivers of tumor aggression, metastasis, and poor clinical outcome in many cancers.In prostate cancer (PCa), hypoxia has been strongly correlated to biochemical failure and local recurrence. However, current PCa treatment options do not address hypoxic cells highlighting a critical gap in existing therapies and the need for development of therapies that target hypoxic prostate tumor cells. Mammalian orthoreovirus (MRV) is an oncolytic virus that targets tumor cells over normal cells which has been shown to be safe and effective against many cancers in vitro, in animal models, and in human clinical trials. We found that MRVinfects and replicates in hypoxic prostate tumor cells to levels comparable to normoxic cells leading to apoptosis and cell death. In addition, the regulatory subunit (HIF-1α) of the master transcriptional regulator of hypoxia, HIF-1, was significantly downregulated in infected cells. HIF-1α downregulation was found to occur via ubiquitin-dependent proteasome-mediated degradation and translational inhibition. Virus-mediated HIF-1α degradation required the HIF-1α PAS domain and expression of the receptor for activated kinase C (RACK1) protein. These data provide evidence that MRV may be a viable therapeutic option for targeting hypoxic cells and HIF-1α in PCa.
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Affiliation(s)
- Pooja Gupta-Saraf
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA
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Huang L, Zhang T, Li S, Duan J, Ye F, Li H, She Z, Gao G, Yang X. Anthraquinone G503 induces apoptosis in gastric cancer cells through the mitochondrial pathway. PLoS One 2014; 9:e108286. [PMID: 25268882 PMCID: PMC4182468 DOI: 10.1371/journal.pone.0108286] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 08/19/2014] [Indexed: 01/08/2023] Open
Abstract
G503 is an anthraquinone compound isolated from the secondary metabolites of a mangrove endophytic fungus from the South China Sea. The present study elucidates the anti-tumor activity and the underlying mechanism of G503. Cell viability assay performed in nine cancer cell lines and two normal cell lines demonstrated that the gastric cancer cell line SGC7901 is the most G503-sensitive cancer cells. G503 induced SGC7901 cell death via apoptosis. G503 exposure activated caspases-3, -8 and -9. Pretreatment with the pan-caspase inhibitor Z-VAD-FMK and caspase-9 inhibitor Z-LEHD-FMK, but not caspase-8 inbibitor Z-IETD-FMK, attenuated the effect of G503. These results suggested that the intrinsic mitochondrial apoptosis pathway, rather than the extrinsic pathway, was involved in G503-induced apoptosis. Furthermore, G503 increased the ratio of Bax to Bcl-2 in the mitochondria and decreased the ratio in the cytosol. G503 treatment resulted in mitochondrial depolarization, cytochrome c release and the subsequent cleavage of caspase -9 and -3. Moreover, it is reported that the endoplasmic reticulum apoptosis pathway may also be activated by G503 by inducing capase-4 cleavage. In consideration of the lower 50% inhibitory concentration for gastric cancer cells, G503 may serve as a promising candidate for gastric cancer chemotherapy.
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Affiliation(s)
- Lijun Huang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Ting Zhang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Shuai Li
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Junting Duan
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Fang Ye
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Hanxiang Li
- Key Laboratory of Functional Molecules from Marine Microorganisms (Sun Yat-sen University), Department of Education of Guangdong Province, Guangzhou, Guangdong Province, China
| | - Zhigang She
- Key Laboratory of Functional Molecules from Marine Microorganisms (Sun Yat-sen University), Department of Education of Guangdong Province, Guangzhou, Guangdong Province, China
| | - Guoquan Gao
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
- China Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong Province, China
| | - Xia Yang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, China
- Key Laboratory of Functional Molecules from Marine Microorganisms (Sun Yat-sen University), Department of Education of Guangdong Province, Guangzhou, Guangdong Province, China
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Sudan S, Rupasinghe HPV. Flavonoid-enriched apple fraction AF4 induces cell cycle arrest, DNA topoisomerase II inhibition, and apoptosis in human liver cancer HepG2 cells. Nutr Cancer 2014; 66:1237-46. [PMID: 25256427 DOI: 10.1080/01635581.2014.951733] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Apples are a major source of dietary phytochemicals such as flavonoids in the Western diet. Here we report anticancer properties and possible mechanism of action of apple flavonoid-enriched fraction (AF4) isolated from the peels of Northern Spy apples in human hepatocellular carcinoma cells, HepG2. Treatment with AF4 induced cell growth inhibition in HepG2 cells in time- and dose-dependent manner. Concentration of 50 μg/ml (50 μg total monomeric polyphenols/ml) AF4 was sufficient to induce a significant reduction in cell viability within 6 h of treatment (92%, P < 0.05) but had very low toxicity (minimum 4% to maximum 16%) on primary liver and lung cells, which was significantly lower than currently prescribed chemotherapy drug Sorafenib (minimum 29% to maximum 49%, P < 0.05). AF4 induced apoptosis in HepG2 cells within 6 h of treatment via activation of caspase-3. Cell cycle analysis via flow-cytometer showed that AF4 induced G2/M phase arrest. Further, results showed that AF4 acts as a strong DNA topoisomerase II catalytic inhibitor, which may be a plausible reason to drive the cells to apoptosis. Overall, our data suggests that AF4 possesses a significantly stronger antiproliferative and specific action than Sorafenib in vitro and is a potential natural chemotherapy agent for treatment of liver cancer.
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Affiliation(s)
- Sudhanshu Sudan
- a Department of Environmental Sciences, Faculty of Agriculture , Dalhousie University , Truro , Nova Scotia , Canada
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54
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Tomasella A, Blangy A, Brancolini C. A receptor-interacting protein 1 (RIP1)-independent necrotic death under the control of protein phosphatase PP2A that involves the reorganization of actin cytoskeleton and the action of cofilin-1. J Biol Chem 2014; 289:25699-710. [PMID: 25096578 PMCID: PMC4162173 DOI: 10.1074/jbc.m114.575134] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/28/2014] [Indexed: 02/02/2023] Open
Abstract
Cell death by necrosis is emerging not merely as a passive phenomenon but as a cell-regulated process. Here, by using different necrotic triggers, we prove the existence of two distinct necrotic pathways. The mitochondrial reactive oxygen species generator 2,3-dimethoxy-1,4-naphthoquinone elicits necrosis characterized by the involvement of RIP1 and Drp1. However, G5, a non-selective isopeptidase inhibitor, triggers a distinct necrotic pathway that depends on the protein phosphatase PP2A and the actin cytoskeleton. PP2A catalytic subunit is stabilized by G5 treatment, and its activity is increased. Furthermore, PP2Ac accumulates into the cytoplasm during necrosis similarly to HMGB1. We have also defined in the actin-binding protein cofilin-1 a link between PP2A, actin cytoskeleton, and necrotic death. Cofilin-1-severing/depolymerization activity is negatively regulated by phosphorylation of serine 3. PP2A contributes to the dephosphorylation of serine 3 elicited by G5. Finally, a cofilin mutant that mimics phosphorylated Ser-3 can partially rescue necrosis in response to G5.
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Affiliation(s)
- Andrea Tomasella
- From the Dipartimento di Scienze Mediche e Biologiche Università degli Studi di Udine, P.le Kolbe 4-33100 Udine, Italy and
| | - Anne Blangy
- CNRS UMR 5237 CRBM Montpellier University 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Claudio Brancolini
- From the Dipartimento di Scienze Mediche e Biologiche Università degli Studi di Udine, P.le Kolbe 4-33100 Udine, Italy and
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Wang X, Stafford W, Mazurkiewicz M, Fryknäs M, Brjnic S, Zhang X, Gullbo J, Larsson R, Arnér ESJ, D'Arcy P, Linder S. The 19S Deubiquitinase inhibitor b-AP15 is enriched in cells and elicits rapid commitment to cell death. Mol Pharmacol 2014; 85:932-45. [PMID: 24714215 DOI: 10.1124/mol.113.091322] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
b-AP15 [(3E,5E)-3,5-bis[(4-nitrophenyl)methylidene]-1-(prop-2-enoyl)piperidin-4-one] is a small molecule inhibitor of the ubiquitin specific peptidase (USP) 14/ubiquitin carboxyl-terminal hydrolase (UCH) L5 deubiquitinases of the 19S proteasome that shows antitumor activity in a number of tumor models, including multiple myeloma. b-AP15 contains an α,β-unsaturated carbonyl unit that is likely to react with intracellular nucleophiles such as cysteine thiolates by Michael addition. We found that binding of b-AP15 to USP14 is partially reversible, and that inhibition of proteasome function is reversible in cells. Despite reversible binding, tumor cells are rapidly committed to apoptosis/cell death after exposure to b-AP15. We show that b-AP15 is rapidly taken up from the medium and enriched in cells. Enrichment provides an explanation of the stronger potency of the compound in cellular assays compared with in vitro biochemical assays. Cellular uptake was impaired by 30-minute pretreatment of cells with low concentrations of N-ethylmaleimide (10 µM), suggesting that enrichment was thiol dependent. We report that in addition to inhibition of deubiquitinases, b-AP15 inhibits the selenoprotein thioredoxin reductase (TrxR). Whereas proteasome inhibition was closely associated with cell death induction, inhibition of TrxR was not. TrxR inhibition is, however, likely to contribute to triggering of oxidative stress observed with b-AP15. Furthermore, we present structure-activity, in vivo pharmacokinetic, and hepatocyte metabolism data for b-AP15. We conclude that the strong enrichment of b-AP15 in cells and a rapid commitment to apoptosis/cell death are factors that likely contribute to the strong antitumor activity of this compound.
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Affiliation(s)
- Xin Wang
- Department of Oncology and Pathology, Cancer Center Karolinska (X.W., M.M., S.B., X.Z., P.D., S.L.), and Division of Biochemistry, Department of Medical Biochemistry and Biophysics (W.S., E.S.J.A.), Karolinska Institute, Stockholm, Sweden; and Division of Clinical Pharmacology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden (M.F., J.G., R.L., S.L.)
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56
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Weathington NM, Mallampalli RK. Emerging therapies targeting the ubiquitin proteasome system in cancer. J Clin Invest 2014; 124:6-12. [PMID: 24382383 DOI: 10.1172/jci71602] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The ubiquitin proteasome system (UPS) is an essential metabolic constituent of cellular physiology that tightly regulates cellular protein concentrations with specificity and precision to optimize cellular function. Inhibition of the proteasome has proven very effective in the treatment of multiple myeloma, and this approach is being tested for utility in other malignancies. New pharmaceuticals targeting the proteasome itself or specific proximal pathways of the UPS are in development as antiproliferatives or immunomodulatory agents. In this article, we discuss the biology of UPS-targeting drugs, their use as therapy for neoplasia, and the state of clinical and preclinical development for emerging therapeutics.
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57
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Manini I, Sgorbissa A, Potu H, Tomasella A, Brancolini C. The DeISGylase USP18 limits TRAIL-induced apoptosis through the regulation of TRAIL levels: Cellular levels of TRAIL influences responsiveness to TRAIL-induced apoptosis. Cancer Biol Ther 2013; 14:1158-66. [PMID: 24153058 DOI: 10.4161/cbt.26525] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising molecule for anti-cancer therapies. Unfortunately, cancer cells frequently acquire resistance to rhTRAIL. Various co-treatments have been proposed to overcome apoptosis resistance to TRAIL. Here we show that downregulation of the deISGylase USP18 sensitizes cancer cells to rhTRAIL, whereas, elevate levels of USP18 inhibit TRAIL-induced apoptosis, in a deISGylase-independent manner. USP18 influences TRAIL signaling through the control of the IFN autocrine loop. In fact, cells with downregulated USP18 expression augment the expression of cellular TRAIL. Downregulation of cellular TRAIL abrogates the synergism between TRAIL and USP18 siRNA and also limits cell death induced by rhTRAIL. By comparing the apoptotic responsiveness to TRAIL in a panel of cancer cell lines, we have discovered a correlation between TRAIL levels and the apoptotic susceptibility to rhTRAIL, In cells expressing high levels of TRAIL-R2 susceptibility to rhTRAIL correlates with TRAIL expression. In conclusion, we propose that cellular TRAIL is an additional factor that can influence the apoptotic response to rhTRAIL.
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Affiliation(s)
- Ivana Manini
- Dipartimento di Scienze Mediche e Biologiche and MATI Center of Excellence; Università degli Studi di Udine; Udine, Italy
| | - Andrea Sgorbissa
- Dipartimento di Scienze Mediche e Biologiche and MATI Center of Excellence; Università degli Studi di Udine; Udine, Italy
| | - Harish Potu
- Dipartimento di Scienze Mediche e Biologiche and MATI Center of Excellence; Università degli Studi di Udine; Udine, Italy
| | - Andrea Tomasella
- Dipartimento di Scienze Mediche e Biologiche and MATI Center of Excellence; Università degli Studi di Udine; Udine, Italy
| | - Claudio Brancolini
- Dipartimento di Scienze Mediche e Biologiche and MATI Center of Excellence; Università degli Studi di Udine; Udine, Italy
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58
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Py B, Kim MS, Vakifahmetoglu-Norberg H, Yuan J. Deubiquitination of NLRP3 by BRCC3 Critically Regulates Inflammasome Activity. Mol Cell 2013; 49:331-8. [DOI: 10.1016/j.molcel.2012.11.009] [Citation(s) in RCA: 399] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 09/12/2012] [Accepted: 11/07/2012] [Indexed: 10/27/2022]
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59
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Siu FM, Lin IWS, Yan K, Lok CN, Low KH, Leung TYC, Lam TL, Che CM. Anticancer dirhodium(ii,ii) carboxylates as potent inhibitors of ubiquitin-proteasome system. Chem Sci 2012. [DOI: 10.1039/c2sc00620k] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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60
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Manns J, Daubrawa M, Driessen S, Paasch F, Hoffmann N, Löffler A, Lauber K, Dieterle A, Alers S, Iftner T, Schulze-Osthoff K, Stork B, Wesselborg S. Triggering of a novel intrinsic apoptosis pathway by the kinase inhibitor staurosporine: activation of caspase-9 in the absence of Apaf-1. FASEB J 2011; 25:3250-61. [PMID: 21659556 DOI: 10.1096/fj.10-177527] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The protein kinase inhibitor staurosporine is one of the most potent and frequently used proapoptotic stimuli, although its mechanism of action is poorly understood. Here, we show that staurosporine as well as its analog 7-hydroxystaurosporine (UCN-01) not only trigger the classical mitochondrial apoptosis pathway but, moreover, activate an additional novel intrinsic apoptosis pathway. Unlike conventional anticancer drugs, staurosporine and UCN-01 induced apoptosis in a variety of tumor cells overexpressing the apoptosis inhibitors Bcl-2 and Bcl-x(L). Furthermore, activation of this novel intrinsic apoptosis pathway by staurosporine did not rely on Apaf-1 and apoptosome formation, an essential requirement for the mitochondrial pathway. Nevertheless, as demonstrated in caspase-9-deficient murine embryonic fibroblasts, human lymphoma cells, and chicken DT40 cells, staurosporine-induced apoptosis was essentially mediated by caspase-9. Our results therefore suggest that, in addition to the classical cytochrome c/Apaf-1-dependent pathway of caspase-9 activation, staurosporine can induce caspase-9 activation and apoptosis independently of the apoptosome. Since staurosporine derivatives have proven efficacy in clinical trials, activation of this novel pathway might represent a powerful target to induce apoptosis in multidrug-resistant tumor cells.
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Affiliation(s)
- Joachim Manns
- Department of Internal Medicine I, Institute for Medical Virology and Epidemiology of Viral Diseases, University of Tübingen, Tübingen, Germany
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61
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Benard G, Neutzner A, Peng G, Wang C, Livak F, Youle RJ, Karbowski M. IBRDC2, an IBR-type E3 ubiquitin ligase, is a regulatory factor for Bax and apoptosis activation. EMBO J 2010; 29:1458-71. [PMID: 20300062 DOI: 10.1038/emboj.2010.39] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 02/18/2010] [Indexed: 11/09/2022] Open
Abstract
Bax, a pro-apoptotic protein from the Bcl-2 family, is central to apoptosis regulation. To suppress spontaneous apoptosis, Bax must be under stringent control that may include regulation of Bax conformation and expression levels. We report that IBRDC2, an IBR-type RING-finger E3 ubiquitin ligase, regulates the levels of Bax and protects cells from unprompted Bax activation and cell death. Downregulation of IBRDC2 induces increased cellular levels and accumulation of the active form of Bax. The ubiquitination-dependent regulation of Bax stability is suppressed by IBRDC2 downregulation and stimulated by IBRDC2 overexpression in both healthy and apoptotic cells. Although mostly cytosolic in healthy cells, upon induction of apoptosis, IBRDC2 accumulates in mitochondrial domains enriched with Bax. Mitochondrial accumulation of IBRDC2 occurs in parallel with Bax activation and also depends on the expression levels of Bcl-xL. Furthermore, IBRDC2 physically interacts with activated Bax. By applying Bax mutants in HCT116 Bax(-/-) cells, combined with the use of active Bax-specific antibodies, we have established that both mitochondrial localization and apoptotic activation of Bax are required for IBRDC2 translocation to the mitochondria.
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Affiliation(s)
- Giovanni Benard
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD, USA
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62
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Abstract
Proteases play a key role in various pathological processes and several protease inhibitors are already available for treatment. DUBs (deubiquitinating enzymes) constitute one of the largest classes of human proteases and are key effectors of the ubiquitin-proteasome system. This pathway regulating cellular protein turnover has been implicated in the pathogenesis of many human diseases, including neurodegenerative disorders, viral diseases and cancer. The therapeutic efficacy of the proteasome inhibitor Velcade (bortezomib) for treating multiple myeloma and mantle cell lymphoma establishes this system as a valid target for cancer treatment. A promising alternative to targeting the proteasome itself would be to target the upstream, ubiquitin conjugation/deconjugation system, to generate more specific, less toxic anticancer agents. Advances in small molecule-based inhibitors specifically targeting DUBs are presented in this review.
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63
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Eldridge AG, O'Brien T. Therapeutic strategies within the ubiquitin proteasome system. Cell Death Differ 2010; 17:4-13. [PMID: 19557013 DOI: 10.1038/cdd.2009.82] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ubiquitin-dependent proteolysis system (UPS) is the main driver of regulated protein degradation in all eukaryotic cells, and it is becoming increasingly clear that defects within this pathway drive a large number of human pathologies. Recent success in the use of proteasome inhibitors in the treatment of hematological malignancies validates the UPS as a viable therapeutic pathway, and substantial effort is now focused on the development of both second-generation proteasome inhibitors as well as novel strategies for the inhibition of upstream UPS enzymes. In this review we discuss the potential 'druggability' of key nodes within the UPS and summarize recent advances within the field.
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Affiliation(s)
- A G Eldridge
- Department of Cell Regulation, Genentech Inc., South San Francisco, CA 94080, USA.
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64
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Potu H, Sgorbissa A, Brancolini C. Identification of USP18 as an important regulator of the susceptibility to IFN-alpha and drug-induced apoptosis. Cancer Res 2010; 70:655-65. [PMID: 20068173 DOI: 10.1158/0008-5472.can-09-1942] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gene products that modify the apoptotic susceptibility of cancer cells may offer novel drug response markers or therapeutic targets. In this study, we probed the contribution of 53 different isopeptidases to apoptosis triggered by bortezomib and etoposide. USP18, a type I IFN-induced protein that deconjugates the ubiquitin-like modifier ISG15 from target proteins, was found to limit apoptotic susceptibility to IFN-alpha or bortezomib. Ablating USP18 in cells treated with IFN-alpha increased tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) production; upregulated expression of transcription factors IFN-regulatory factor (IRF)-1, IRF-7, and IRF-9; and promoted the extrinsic pathway of apoptosis. The proapoptotic effects of ablating USP18 were abrogated by FLIP overexpression or TRAIL silencing. However, in bortezomib-treated cells, weak spontaneous signaling from type I IFNs was implicated in the proapoptotic effect of USP18 ablation. Ectopic USP18 repressed apoptotic signaling by IFN-alpha, TRAIL, or bortezomib. Similar effects were produced by a catalytically inactive USP18 mutant, indicating that the antiapoptotic function of USP18 is independent of its catalytic activity. These findings suggest that USP18 may significantly limit operation of the extrinsic apoptotic pathway triggered by type I IFN and drugs.
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Affiliation(s)
- Harish Potu
- Dipartimento di Scienze e Tecnologie Biomediche, Universita' di Udine, 33100 Udine, Italy
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65
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Landais I, Hiddingh S, McCarroll M, Yang C, Sun A, Turker MS, Snyder JP, Hoatlin ME. Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors. Mol Cancer 2009; 8:133. [PMID: 20043851 PMCID: PMC2807854 DOI: 10.1186/1476-4598-8-133] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/31/2009] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The Fanconi anemia (FA) pathway is a multigene DNA damage response network implicated in the repair of DNA lesions that arise during replication or after exogenous DNA damage. The FA pathway displays synthetic lethal relationship with certain DNA repair genes such as ATM (Ataxia Telangectasia Mutated) that are frequently mutated in tumors. Thus, inhibition of FANCD2 monoubiquitylation (FANCD2-Ub), a key step in the FA pathway, might target tumor cells defective in ATM through synthetic lethal interaction. Curcumin was previously identified as a weak inhibitor of FANCD2-Ub. The aim of this study is to identify derivatives of curcumin with better activity and specificity. RESULTS Using a replication-free assay in Xenopus extracts, we screened monoketone analogs of curcumin for inhibition of FANCD2-Ub and identified analog EF24 as a strong inhibitor. Mechanistic studies suggest that EF24 targets the FA pathway through inhibition of the NF-kB pathway kinase IKK. In HeLa cells, nanomolar concentrations of EF24 inhibited hydroxyurea (HU)-induced FANCD2-Ub and foci in a cell-cycle independent manner. Survival assays revealed that EF24 specifically sensitizes FA-competent cells to the DNA crosslinking agent mitomycin C (MMC). In addition, in contrast with curcumin, ATM-deficient cells are twofold more sensitive to EF24 than matched wild-type cells, consistent with a synthetic lethal effect between FA pathway inhibition and ATM deficiency. An independent screen identified 4H-TTD, a compound structurally related to EF24 that displays similar activity in egg extracts and in cells. CONCLUSIONS These results suggest that monoketone analogs of curcumin are potent inhibitors of the FA pathway and constitute a promising new class of targeted anticancer compounds.
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Affiliation(s)
- Igor Landais
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, USA.
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66
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Foti C, Florean C, Pezzutto A, Roncaglia P, Tomasella A, Gustincich S, Brancolini C. Characterization of caspase-dependent and caspase-independent deaths in glioblastoma cells treated with inhibitors of the ubiquitin-proteasome system. Mol Cancer Ther 2009; 8:3140-50. [PMID: 19887551 DOI: 10.1158/1535-7163.mct-09-0431] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The regulation of the necrotic death and its relevance in anticancer therapy are largely unknown. Here, we have investigated the proapoptotic and pronecrotic activities of two ubiquitin-proteasome system inhibitors: bortezomib and G5. The present study points out that the glioblastoma cell lines U87MG and T98G are useful models to study the susceptibility to apoptosis and necrosis in response to ubiquitin-proteasome system inhibitors. U87MG cells show resistance to apoptosis induced by bortezomib and G5, but they are more susceptible to necrosis induced by G5. Conversely, T98G cells are more susceptible to apoptosis induced by both inhibitors but show some resistance to G5-induced necrosis. No overt differences in the induction of Noxa and Mcl-1 or in the expression levels of other components of the apoptotic machinery were observed between U87MG and T98G cells. Instead, by comparing the transcriptional profiles of the two cell lines, we have found that the resistance to G5-induced necrosis could arise from differences in glutathione synthesis/utilization and in the microenvironment. In particular, collagen IV, which is highly expressed in T98G cells, and fibronectin, whose adhesive function is counteracted by tenascin-C in U87MG cells, can restrain the necrotic response to G5. Collectively, our results provide an initial characterization of the molecular signals governing cell death by necrosis in glioblastoma cell lines.
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Affiliation(s)
- Carmela Foti
- Dipartimento di Scienze e Tecnologie Biomediche, Sezione di Biologia Universita' di Udine, Udine, Italy
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67
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Lin CP, Ban Y, Lyu YL, Liu LF. Proteasome-dependent processing of topoisomerase I-DNA adducts into DNA double strand breaks at arrested replication forks. J Biol Chem 2009; 284:28084-28092. [PMID: 19666469 DOI: 10.1074/jbc.m109.030601] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Reversible topoisomerase I (Top1)-DNA cleavage complexes are the key DNA lesion induced by anticancer camptothecins (CPTs) (e.g. topotecan and irinotecan) as well as structurally perturbed DNAs (e.g. oxidatively damaged, UV-irradiated, or alkylated DNA). It has been proposed that Top1 cleavage complexes arrest advancing replication forks, triggering the formation of DNA double strand breaks (DSBs) because of replication fork runoff at the Top1 cleavage complex sites on the leading strand. In this study, we show that the formation of replication-dependent DSBs requires the ubiquitin-proteasome pathway in CPT-treated cells. First, the proteasome inhibitor MG-132 specifically inhibited CPT-induced but not ionizing radiation- or hydroxyurea-induced DSBs as revealed by both the neutral comet assay and measurements of the specific DNA damage signals (e.g. gamma-H2AX, phosphorylated ataxia telangiectasia mutated (Ser-1981), and phosphorylated Chk2 (Ser-33/35)) that are characteristic for DSBs. Knocking down the 20 S proteasome maturation protein also supported the requirement of the proteasome activity for CPT-induced DSBs. Second, CPT-induced DSB signals were shown to require ubiquitin, ubiquitin-activating enzyme (E1), a CUL-3-based ubiquitin ligase (E3), and the formation of Lys-48-linked polyubiquitin chains on Top1. Third, immunocytochemical studies revealed that the CPT-induced formation of gamma-H2AX foci occurred at the replication forks and was attenuated by co-treatment with the proteasome inhibitor MG-132. In the aggregate, these results support a replication fork collision model in which Top1 cleavage complexes at the arrested replication forks are degraded by proteasome prior to replication fork runoff on the leading strand to generate DSBs.
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Affiliation(s)
- Chao-Po Lin
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635
| | - Yi Ban
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635
| | - Yi Lisa Lyu
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635
| | - Leroy F Liu
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635.
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68
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Protective effects of caspase-9 and poly(ADP-ribose) polymerase inhibitors on ischemia-reperfusion-induced myocardial injury. Arch Pharm Res 2009; 32:1037-43. [DOI: 10.1007/s12272-009-1709-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 05/20/2009] [Accepted: 06/30/2009] [Indexed: 11/26/2022]
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69
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Berndtsson M, Beaujouin M, Rickardson L, Havelka AM, Larsson R, Westman J, Liaudet-Coopman E, Linder S. Induction of the lysosomal apoptosis pathway by inhibitors of the ubiquitin-proteasome system. Int J Cancer 2009; 124:1463-9. [DOI: 10.1002/ijc.24004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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70
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Fontanini A, Foti C, Potu H, Crivellato E, Maestro R, Bernardi P, Demarchi F, Brancolini C. The Isopeptidase Inhibitor G5 Triggers a Caspase-independent Necrotic Death in Cells Resistant to Apoptosis: A COMPARATIVE STUDY WITH THE PROTEASOME INHIBITOR BORTEZOMIB. J Biol Chem 2009; 284:8369-81. [PMID: 19139105 DOI: 10.1074/jbc.m806113200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Inhibitors of the ubiquitin-proteasome system (UPSIs) promote apoptosis of cancer cells and show encouraging anti-tumor activities in vivo. In this study, we evaluated the death activities of two different UPSIs: bortezomib and the isopeptidase inhibitor G5. To unveil whether these compounds elicit different types of death, we compared their effect both on apoptosis-proficient wild type mouse embryo fibroblasts and on cells defective for apoptosis (double-deficient Bax/Bak mouse embryo fibroblasts) (double knockout; DKO). We have discovered that (i) both inhibitors induce apoptosis in a Bax and Bak-dependent manner, (ii) both inhibitors elicit autophagy in WT and DKO cells, and (iii) only G5 can kill apoptosis-resistant DKO cells by activating a necrotic response. The induction of necrosis was confirmed by different experimental approaches, including time lapse analysis, HMGB1 release, and electron microscopy studies. Neither treatment with antinecrotic agents, such as antioxidants, poly(ADP-ribose) polymerase and JNK inhibitors, necrostatin, and the intracellular Ca(2+) chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, nor overexpression of Bcl-2 and Bcl-xL prevented necrosis induced by G5. This necrotic death is characterized by the absence of protein oxidation and by the rapid cyclosporin A-independent dissipation of the mitochondrial membrane potential. Notably, a peculiar feature of the G5-induced necrosis is an early and dramatic reorganization of the actin cytoskeleton, coupled to an alteration of cell adhesion. The importance of cell adhesion impairment in the G5-induced necrotic death of DKO cells was confirmed by the antagonist effect of the extracellular matrix-adhesive components, collagen and fibronectin.
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Affiliation(s)
- Alessandra Fontanini
- Dipartimento di Scienze e Tecnologie Biomediche, Sezione di Biologia, and MATI Center of Excellence
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71
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Das U, Sharma RK, Dimmock JR. 1,5-diaryl-3-oxo-1,4-pentadienes: a case for antineoplastics with multiple targets. Curr Med Chem 2009; 16:2001-20. [PMID: 19519378 PMCID: PMC3326067 DOI: 10.2174/092986709788682218] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A number of organic molecules which contain the 1,5-diaryl-3-oxo-1,4-pentadienyl group, referred to hereafter as the dienone moiety, have antineoplastic properties. Emphasis is made on the attachment of this structural moiety to several molecular scaffolds, namely piperidines, N-acylpiperidines, cycloalkanes and 3,4-dihydro-1H-napthalenes. Many of these compounds are potent cytotoxins having micromolar and nanomolar IC(50) values towards a wide range of neoplastic and transformed cells. On occasions, greater toxicity towards neoplasms than normal cells has been demonstrated. A number of these compounds have in vivo anticancer properties and in general excellent tolerability in rodents is demonstrated. The way in which a number of physicochemical properties such as redox potentials, torsion angles, atomic charges and logP values govern cytotoxic potencies are presented. The importance of the shapes of different compounds as determined by molecular modeling in contributing to antineoplastic properties is outlined. Arguments are presented in favour of designing antineoplastics which have multiple sites of action in contrast to those bioactive molecules which have only one molecular target. A number of compounds which possess the dienone group have different modes of action some of which are chronicled in this review, such as inducing apoptosis, affecting respiration in mitochondria, inhibiting macromolecular biosynthesis and both inhibiting and stimulating certain enzymes. Other important properties of these compounds are discussed including their anti-angiogenic, MDR-revertant and antioxidant properties. It is hoped that this eulogy of the importance of the dienone group will encourage researchers to consider incorporating this structural unit into candidate cytotoxins in the future.
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Affiliation(s)
- U Das
- Drug Design and Discovery Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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72
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Lin CP, Ban Y, Lyu YL, Desai SD, Liu LF. A ubiquitin-proteasome pathway for the repair of topoisomerase I-DNA covalent complexes. J Biol Chem 2008; 283:21074-83. [PMID: 18515798 PMCID: PMC2475699 DOI: 10.1074/jbc.m803493200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 05/28/2008] [Indexed: 01/23/2023] Open
Abstract
Reversible topoisomerase I (Top1)-DNA cleavage complexes are the key DNA lesion induced by anticancer camptothecins (e.g. topotecan and irinotecan) as well as structurally perturbed DNAs (e.g. oxidatively damaged DNA, UV-irradiated DNA, alkylated DNA, uracil-substituted DNA, mismatched DNA, gapped and nicked DNA, and DNA with abasic sites). Top1 cleavage complexes arrest transcription and trigger transcription-dependent degradation of Top1, a phenomenon termed Top1 down-regulation. In the current study, we have investigated the role of Top1 down-regulation in the repair of Top1 cleavage complexes. Using quiescent (serum-starved) human WI-38 cells, camptothecin (CPT) was shown to induce Top1 down-regulation, which paralleled the induction of DNA single-strand breaks (SSBs) (assayed by comet assays) and ATM autophosphorylation (at Ser-1981). Interestingly, Top1 down-regulation, induction of DNA SSBs and ATM autophosphorylation were all abolished by the proteasome inhibitor MG132. Furthermore, studies using immunoprecipitation and dominant-negative ubiquitin mutants have suggested a specific requirement for the assembly of Lys-48-linked polyubiquitin chains for CPT-induced Top1 down-regulation. In contrast to the effect of proteasome inhibition, inactivation of PARP1 was shown to increase the amount of CPT-induced SSBs and the level of ATM autophosphorylation. Together, these results support a model in which Top1 cleavage complexes arrest transcription and activate a ubiquitin-proteasome pathway leading to the degradation of Top1 cleavage complexes. Degradation of Top1 cleavage complexes results in the exposure of Top1-concealed SSBs for repair through a PARP1-dependent process.
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Affiliation(s)
| | | | | | | | - Leroy F. Liu
- Department of Pharmacology, University of Medicine and Dentistry of New
Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
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73
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Nicholson B, Leach CA, Goldenberg SJ, Francis DM, Kodrasov MP, Tian X, Shanks J, Sterner DE, Bernal A, Mattern MR, Wilkinson KD, Butt TR. Characterization of ubiquitin and ubiquitin-like-protein isopeptidase activities. Protein Sci 2008; 17:1035-43. [PMID: 18424514 PMCID: PMC2386736 DOI: 10.1110/ps.083450408] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 03/08/2008] [Accepted: 03/10/2008] [Indexed: 11/24/2022]
Abstract
Conjugation or deconjugation of ubiquitin (Ub) or ubiquitin-like proteins (UBLs) to or from cellular proteins is a multifaceted and universal means of regulating cellular physiology, controlling the lifetime, localization, and activity of many critical proteins. Deconjugation of Ub or UBL from proteins is performed by a class of proteases called isopeptidases. Herein is described a readily quantifiable novel isopeptidase assay platform consisting of Ub or UBL fused to the reporter enzyme phospholipase A(2) (PLA(2)). Isopeptidase activity releases PLA(2), which cleaves its substrate, generating a signal that is linear with deubiquitylase (DUB) concentration and is able to discriminate DUB, deSUMOylase, deNEDDylase, and deISGylase activities. The power and sensitivity of the UBL-PLA(2) assay are demonstrated by its ability to differentiate the contrasting deISGylase and DUB activities of two coronavirus proteases: severe acute respiratory syndrome papain-like protease (SARS-CoV PLpro) and NL63 CoV papain-like protease 2 (PLP2). Furthermore, direct comparisons with the current Ub-7-amino-4-methylcoumarin (Ub-AMC) assay demonstrated that the Ub-PLA(2) assay is an effective tool for characterizing modulators of isopeptidase activity. This observation was expanded by profiling the inhibitory activity of the nonselective isopeptidase inhibitor NSC 632839 against DUBs and deSUMOylases. Taken together, these studies illustrate the utility of the reporter-based approach to measuring isopeptidase activity.
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Affiliation(s)
- Benjamin Nicholson
- Division of Research and Development, Progenra, Inc., Malvern, Pennsylvania 19355, USA.
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74
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Jones NC, Lynn ML, Gaudenz K, Sakai D, Aoto K, Rey JP, Glynn EF, Ellington L, Du C, Dixon J, Dixon MJ, Trainor PA. Prevention of the neurocristopathy Treacher Collins syndrome through inhibition of p53 function. Nat Med 2008; 14:125-33. [PMID: 18246078 DOI: 10.1038/nm1725] [Citation(s) in RCA: 325] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 01/07/2008] [Indexed: 01/15/2023]
Abstract
Treacher Collins syndrome (TCS) is a congenital disorder of craniofacial development arising from mutations in TCOF1, which encodes the nucleolar phosphoprotein Treacle. Haploinsufficiency of Tcof1 perturbs mature ribosome biogenesis, resulting in stabilization of p53 and the cyclin G1-mediated cell-cycle arrest that underpins the specificity of neuroepithelial apoptosis and neural crest cell hypoplasia characteristic of TCS. Here we show that inhibition of p53 prevents cyclin G1-driven apoptotic elimination of neural crest cells while rescuing the craniofacial abnormalities associated with mutations in Tcof1 and extending life span. These improvements, however, occur independently of the effects on ribosome biogenesis; thus suggesting that it is p53-dependent neuroepithelial apoptosis that is the primary mechanism underlying the pathogenesis of TCS. Our work further implies that neuroepithelial and neural crest cells are particularly sensitive to cellular stress during embryogenesis and that suppression of p53 function provides an attractive avenue for possible clinical prevention of TCS craniofacial birth defects and possibly those of other neurocristopathies.
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Affiliation(s)
- Natalie C Jones
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, Missouri 64110, USA
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75
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Rupinder SK, Gurpreet AK, Manjeet S. Cell suicide and caspases. Vascul Pharmacol 2007; 46:383-93. [PMID: 17382599 DOI: 10.1016/j.vph.2007.01.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 01/11/2007] [Accepted: 01/24/2007] [Indexed: 01/09/2023]
Abstract
Programmed cell death or apoptosis is a well regulated physiological form of cellular autodestruction. It plays an essential role in embryonic development, homeostasis, remodeling, surveillance, and host defense mechanisms. Conversely dysregulation of apoptosis, resulting in either too less or excessive cell death is implicated in pathogenesis of stroke, myocardial infarction, neurodegenerative diseases, cancer and autoimmmune disorders. Apoptosis is coordinated by a family of cysteine proteinases called caspases, which dismantle the cell by targeting panoply of proteins. The mammalian caspase family contains 14 members, a subset participates in cellular demise and the remaining are involved in the processing of pro-inflammatory cytokines. We have tried to develop a simplified picture of basic apoptotic mechanisms on the basis of recent insights into the area.
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Affiliation(s)
- Sodhi K Rupinder
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India.
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