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El-Mayet FS, Santos VC, Wijesekera N, Lubbers S, Harrison KS, Sadeghi H, Jones C. Glucocorticoid receptor and specificity protein 1 (Sp1) or Sp3, but not the antibiotic Mithramycin A, stimulates human alphaherpesvirus 1 (HSV-1) replication. Antiviral Res 2024; 225:105870. [PMID: 38556059 PMCID: PMC11109923 DOI: 10.1016/j.antiviral.2024.105870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/15/2024] [Accepted: 03/22/2024] [Indexed: 04/02/2024]
Abstract
Following acute human alphaherpesvirus 1 (HSV-1) infection of oral-facial mucosal surfaces, sensory neurons in trigeminal ganglia (TG) are important sites for life-long latency. Neurons in the central nervous system, including brainstem, also harbor viral genomes during latency. Periodically, certain cellular stressors trigger reactivation from latency, which can lead to recurrent HSV-1 disease: herpes labialis, herpes stromal keratitis, and encephalitis for example. Activation of the glucocorticoid receptor (GR) by stressful stimuli enhances HSV-1 gene expression, replication, and explant-induced reactivation. GR and certain stress-induced Krüppel like factors (KLF) cooperatively transactivate cis-regulatory modules (CRM) that drive expression of viral transcriptional regulatory proteins (ICP0, ICP4, and ICP27). These CRMs lack GR response elements (GRE); however, specificity protein 1 (Sp1) binding sites are crucial for GR and KLF15 or KLF4 mediated transactivation. Hence, we tested whether Sp1 or Sp3 regulate viral replication and transactivation of the ICP0 promoter. During early stages of explant-induced reactivation from latency, the number of Sp3+ TG neurons were significantly higher relative to TG from latently infected mice. Conversely, Sp1+ TG neurons were only increased in females, but not male mice, during explant-induced reactivation. Sp1 siRNA significantly reduced HSV-1 replication in cultured mouse (Neuro-2A) and monkey (CV-1) cells. Mithramycin A, an antibiotic that has anti-tumor activity preferentially interacts with GC-rich DNA, including Sp1 binding sites, significantly reduced HSV-1 replication indicating it has antiviral activity. GR and Sp1 or Sp3 transactivated the HSV-1 ICP0 promoter in Neuro-2A and CV-1 cells confirming these transcription factors enhance viral replication and gene expression.
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Affiliation(s)
- Fouad S El-Mayet
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA; Benha University, Faculty of Veterinary Medicine, Department of Virology, Moshtohor, 13736, Kaliobyia, Egypt
| | - Vanessa Claire Santos
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA
| | - Nishani Wijesekera
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA
| | - Sydney Lubbers
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA
| | - Kelly S Harrison
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA
| | - Hafez Sadeghi
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA
| | - Clinton Jones
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, OK, USA.
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El-mayet FS, Jones C. Specificity protein 1 (Sp1) and glucocorticoid receptor (GR) stimulate bovine alphaherpesvirus 1 (BoHV-1) replication and cooperatively transactivate the immediate early transcription unit 1 promoter. J Virol 2024; 98:e0143623. [PMID: 38084958 PMCID: PMC10804982 DOI: 10.1128/jvi.01436-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/22/2023] [Indexed: 01/24/2024] Open
Abstract
Bovine alphaherpesvirus 1 (BoHV-1) infections cause respiratory tract disorders and suppress immune responses, which can culminate in bacterial pneumonia. Following acute infection, BoHV-1 establishes lifelong latency in sensory neurons present in trigeminal ganglia (TG) and unknown cells in pharyngeal tonsil. Latently infected calves consistently reactivate from latency after an intravenous injection of the synthetic corticosteroid dexamethasone (DEX), which mimics the effects of stress. The immediate early transcription unit 1 (IEtu1) promoter drives expression of infected cell protein 0 (bICP0) and bICP4, two key viral transcriptional regulators. The IEtu1 promoter contains two functional glucocorticoid receptor (GR) response elements (GREs), and this promoter is transactivated by GR, DEX, and certain Krüppel transcription factors that interact with GC-rich motifs, including consensus specificity protein 1 (Sp1) binding sites. Based on these observations, we hypothesized that Sp1 stimulates productive infection and transactivates key BoHV-1 promoters. DEX treatment of latently infected calves increased the number of Sp1+ TG neurons and cells in pharyngeal tonsil indicating that Sp1 expression is induced by stress. Silencing Sp1 protein expression with siRNA or mithramycin A, a drug that preferentially binds GC-rich DNA, significantly reduced BoHV-1 replication. Moreover, BoHV-1 infection of permissive cells increased Sp1 steady-state protein levels. In transient transfection studies, GR and Sp1 cooperatively transactivate IEtu1 promoter activity unless both GREs are mutated. Co-immunoprecipitation studies revealed that GR and Sp1 interact in mouse neuroblastoma cells (Neuro-2A) suggesting this interaction stimulates IEtu1 promoter activity. Collectively, these studies suggested that the cellular transcription factor Sp1 enhances productive infection and stress-induced BoHV-1 reactivation from latency.IMPORTANCEFollowing acute infection, bovine alphaherpesvirus 1 (BoHV-1) establishes lifelong latency in sensory neurons in trigeminal ganglia (TG) and pharyngeal tonsil. The synthetic corticosteroid dexamethasone consistently induces BoHV-1 reactivation from latency. The number of TG neurons and cells in pharyngeal tonsil expressing the cellular transcription factor specificity protein 1 (Sp1) protein increases during early stages of dexamethasone-induced reactivation from latency. Silencing Sp1 expression impairs BoHV-1 replication in permissive cells. Interestingly, mithramycin A, a neuroprotective antibiotic that preferentially binds GC-rich DNA, impairs Sp1 functions and reduces BoHV-1 replication suggesting that it is a potential antiviral drug. The glucocorticoid receptor (GR) and Sp1 cooperatively transactivate the BoHV-1 immediate early transcript unit 1 (IEtu1) promoter, which drives expression of infected cell protein 0 (bICP0) and bICP4. Mithramycin A also reduced Sp1- and GR-mediated transactivation of the IEtu1 promoter. These studies revealed that GR and Sp1 trigger viral gene expression and replication following stressful stimuli.
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Affiliation(s)
- Fouad S. El-mayet
- Department of Veterinary Pathobiology, Oklahoma State University, College of Veterinary Medicine, Stillwater, Oklahoma, USA
- Department of Virology, Benha University, Faculty of Veterinary Medicine, Benha, Egypt
| | - Clinton Jones
- Department of Veterinary Pathobiology, Oklahoma State University, College of Veterinary Medicine, Stillwater, Oklahoma, USA
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Mithramycin A Inhibits Colorectal Cancer Growth by Targeting Cancer Stem Cells. Sci Rep 2019; 9:15202. [PMID: 31645574 PMCID: PMC6811578 DOI: 10.1038/s41598-019-50917-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/16/2019] [Indexed: 01/20/2023] Open
Abstract
The pivotal role of cancer initiating stem cells (CSCs) in tumor initiation, growth, metastasis and drug resistance has led to the postulation of a 'total cancer therapy' paradigm, which involves targeting both cancer cells and CSCs for effective therapy. However, the progress in identifying drugs for total cancer therapy has been limited. Herein, we show for the first time that mithramycin A (Mit-A) can successfully inhibit CSC proliferation, in addition to inhibiting bulk cancer cells in a model of colorectal cancer (CRC), the second leading cause of death among men and women in the United States. To this end, a polymeric nanofiber scaffold culture system was established to develop 3D tumor organoids (tumoroids) from CRC cell lines such as HT29, HCT116, KM12, CT26 and MC38 as well as ex vivo mouse tumors. These tumoroids possessed increased expression of CSC markers and transcription factors, expanded the number of CSCs in culture and increased CSC functional properties measured by aldehyde dehydrogenase activity. Screening of an NCI library of FDA approved drugs led to the identification of Mit-A as a potential total cancer therapy drug. In both sphere and tumoroid culture, Mit-A inhibits cancer growth by reducing the expression of cancer stemness markers. In addition, Mit-A inhibits the expression of SP1, a previously known target in CRCs. Moreover, Mit-A significantly reduces growth of tumoroids in ex vivo cultures and CRC tumor growth in vivo. Finally, a dose-dependent treatment on CRC cells indicate that Mit-A significantly induces the cell death and PARP-cleavage of both CSC and non-CSC cells. Taken together the results of these in vitro, ex vivo and in vivo studies lead to the inference that Mit-A is a promising drug candidate for total cancer therapy of CRCs.
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Satange R, Chang CK, Hou MH. A survey of recent unusual high-resolution DNA structures provoked by mismatches, repeats and ligand binding. Nucleic Acids Res 2019; 46:6416-6434. [PMID: 29945186 PMCID: PMC6061790 DOI: 10.1093/nar/gky561] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022] Open
Abstract
The structure of the DNA duplex is arguably one of the most important biological structures elucidated in modern history. DNA duplex structure is closely associated with essential biological functions such as DNA replication and RNA transcription. In addition to the classical A-, B- and Z-DNA conformations, DNA duplexes are capable of assuming a variety of alternative conformations depending on the sequence and environmental context. A considerable number of these unusual DNA duplex structures have been identified in the past decade, and some of them have been found to be closely associated with different biological functions and pathological conditions. In this manuscript, we review a selection of unusual DNA duplex structures, particularly those originating from base pair mismatch, repetitive sequence motifs and ligand-induced structures. Although the biological significance of these novel structures has not yet been established in most cases, the illustrated conformational versatility of DNA could have relevance for pharmaceutical or nanotechnology development. A perspective on the future directions of this field is also presented.
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Affiliation(s)
- Roshan Satange
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan.,Ph.D. Program in Medical Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chung-Ke Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ming-Hon Hou
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan.,Ph.D. Program in Medical Biotechnology, National Chung Hsing University, Taichung, Taiwan
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Weidenbach S, Hou C, Chen JM, Tsodikov OV, Rohr J. Dimerization and DNA recognition rules of mithramycin and its analogues. J Inorg Biochem 2015; 156:40-7. [PMID: 26760230 DOI: 10.1016/j.jinorgbio.2015.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/10/2015] [Accepted: 12/16/2015] [Indexed: 12/25/2022]
Abstract
The antineoplastic and antibiotic natural product mithramycin (MTM) is used against cancer-related hypercalcemia and, experimentally, against Ewing sarcoma and lung cancers. MTM exerts its cytotoxic effect by binding DNA as a divalent metal ion (Me(2+))-coordinated dimer and disrupting the function of transcription factors. A precise molecular mechanism of action of MTM, needed to develop MTM analogues selective against desired transcription factors, is lacking. Although it is known that MTM binds G/C-rich DNA, the exact DNA recognition rules that would allow one to map MTM binding sites remain incompletely understood. Towards this goal, we quantitatively investigated dimerization of MTM and several of its analogues, MTM SDK (for Short side chain, DiKeto), MTM SA-Trp (for Short side chain and Acid), MTM SA-Ala, and a biosynthetic precursor premithramycin B (PreMTM B), and measured the binding affinities of these molecules to DNA oligomers of different sequences and structural forms at physiological salt concentrations. We show that MTM and its analogues form stable dimers even in the absence of DNA. All molecules, except for PreMTM B, can bind DNA with the following rank order of affinities (strong to weak): MTM=MTM SDK>MTM SA-Trp>MTM SA-Ala. An X(G/C)(G/C)X motif, where X is any base, is necessary and sufficient for MTM binding to DNA, without a strong dependence on DNA conformation. These recognition rules will aid in mapping MTM sites across different promoters towards development of MTM analogues as useful anticancer agents.
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Affiliation(s)
- Stevi Weidenbach
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Caixia Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Jhong-Min Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
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Banerjee A, Sanyal S, Kulkarni KK, Jana K, Roy S, Das C, Dasgupta D. Anticancer drug mithramycin interacts with core histones: An additional mode of action of the DNA groove binder. FEBS Open Bio 2014; 4:987-95. [PMID: 25473595 PMCID: PMC4247356 DOI: 10.1016/j.fob.2014.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/23/2014] [Accepted: 10/12/2014] [Indexed: 01/13/2023] Open
Abstract
Mithramycin (MTR) is a clinically approved DNA-binding antitumor antibiotic currently in Phase 2 clinical trials at National Institutes of Health for treatment of osteosarcoma. In view of the resurgence in the studies of this generic antibiotic as a human medicine, we have examined the binding properties of MTR with the integral component of chromatin - histone proteins - as a part of our broad objective to classify DNA-binding molecules in terms of their ability to bind chromosomal DNA alone (single binding mode) or both histones and chromosomal DNA (dual binding mode). The present report shows that besides DNA, MTR also binds to core histones present in chromatin and thus possesses the property of dual binding in the chromatin context. In contrast to the MTR-DNA interaction, association of MTR with histones does not require obligatory presence of bivalent metal ion like Mg(2+). As a consequence of its ability to interact with core histones, MTR inhibits histone H3 acetylation at lysine 18, an important signature of active chromatin, in vitro and ex vivo. Reanalysis of microarray data of Ewing sarcoma cell lines shows that upon MTR treatment there is a significant down regulation of genes, possibly implicating a repression of H3K18Ac-enriched genes apart from DNA-binding transcription factors. Association of MTR with core histones and its ability to alter post-translational modification of histone H3 clearly indicates an additional mode of action of this anticancer drug that could be implicated in novel therapeutic strategies.
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Key Words
- BAC, benzalkonium chloride
- BSA, bovine serum albumin
- CBP, CREB-binding protein
- CD, circular dichroism
- Core histones
- Dual binding mode
- EM, electron microscopy
- EWS-FLI1, transcription factor with a DNA binding domain FLI1 and a transcription enhancer domain EWS
- Epigenetic modulator
- FACS, fluorescence activated cell sorting
- H3K18 acetylation
- H3K18Ac, histone H3 lysine 18 acetylation
- HAT, histone acetyltransferase
- HD, Huntington’s disease
- ITC, isothermal titration calorimetry
- M2+, bivalent metal ion such as Mg2+
- MTR, mithramycin
- MTT, 3-(4-5 dimethylthiazol-2-yl) 2-5diphenyl-tetrazolium bromide
- Mithramycin
- NIH, National Institutes of Health
- PBS, phosphate-buffered saline
- PTM, post-translational modification
- SGR, sanguinarine
- TBST, Tris-buffered saline Tween-20
- TCA, trichloroacetic acid
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Affiliation(s)
- Amrita Banerjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Sulagna Sanyal
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Kirti K Kulkarni
- Bionivid Technology Pvt Ltd, Kasturi Nagar, Bangalore 560043, India
| | - Kuladip Jana
- Division of Molecular Medicine, Centre for Translational Animal Research, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, West Bengal, India
| | - Siddhartha Roy
- Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Chandrima Das
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
| | - Dipak Dasgupta
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-1, Bidhan Nagar, Kolkata 700064, West Bengal, India
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Dutta S, Lahiri S, Banerjee A, Saha S, Dasgupta D. Association of antitumor antibiotic Mithramycin with Mn2+ and the potential cellular targets of Mithramycin after association with Mn2+. J Biomol Struct Dyn 2014; 33:434-46. [PMID: 24559512 DOI: 10.1080/07391102.2014.887031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Mithramycin (MTR), an aureolic acid group of antitumor antibiotic is used for the treatment of several types of tumors. We have reported here the association of MTR with an essential micronutrient, manganese (Mn(2+)). Spectroscopic methods have been used to characterize and understand the kinetics and mechanism of complex formation between them. MTR forms a single type of complex with Mn(2+) in the mole ratio of 2:1 [MTR: Mn(2+)] via a two step kinetic process. Circular dichroism (CD) spectroscopic study indicates that the complex [(MTR)2 Mn(2+)] has a right-handed twist conformation similar in structure with the complexes reported for Mg(2+) and Zn(2+). This conformation allows binding via minor groove of DNA with (G, C) base preference during the interaction with double-stranded B-DNA. Using absorbance, fluorescence, and CD spectroscopy we have shown that [(MTR)2 Mn(2+)] complex binds to double-stranded DNA with an apparent dissociation constant of 32 μM and binding site size of 0.2 (drug/nucleotide). It binds to chicken liver chromatin with apparent dissociation constant value 298 μM. Presence of histone proteins in chromatin inhibits the accessibility of the complex for chromosomal DNA. We have also shown that MTR binds to Mn(2+) containing metalloenzyme manganese superoxide dismutase from Escherichia coli.
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Affiliation(s)
- Shreyasi Dutta
- a Biophysics & Structural Genomics Division , Saha Institute of Nuclear Physics , Block-AF, Sector-I, Bidhan Nagar, Kolkata - 700 064 , India
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Zavala K, Lee J, Chong J, Sharma M, Eilers H, Schumacher MA. The anticancer antibiotic mithramycin-A inhibits TRPV1 expression in dorsal root ganglion neurons. Neurosci Lett 2014; 578:211-6. [PMID: 24468003 DOI: 10.1016/j.neulet.2014.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/13/2014] [Accepted: 01/14/2014] [Indexed: 12/17/2022]
Abstract
Activation of peripheral nociceptors by products of inflammation has been shown to be dependent on specific sensory transducing elements such as the capsaicin receptor, TRPV1. The development of high-affinity antagonists to TRPV1 as well as to other receptors capable of detecting noxious stimuli has now become a major focus in analgesic development. Another critical feature of nociception is the relative abundance of a particular pain transducing receptor under normal or pathophysiologic conditions. Increases in expression and/or changes in distribution of nociceptive receptors such as TRPV1 have been correlated with progression of tissue injury and persistence of pain behaviors. Although some details are emerging as to what regulates nociceptor-specific gene expression, compounds that could potentially be used to block or reverse over-expression of nociceptive gene expression are essentially absent. In our efforts to better understand the transcriptional regulation of TRPV1 in sensory neurons, we identified an anticancer agent, mithramycin-A, that decreased TRPV1 expression in primary rat dorsal root ganglion (DRG) neurons. Mithramycin-A dose-dependently (10-50 nM) decreased endogenous TRPV1 mRNA content and appeared to decrease TRPV1-like protein expression in DRG neurons. We also observed that mithramycin-A directed a decrease in the number of capsaicin-responsive DRG neurons without a significant change in the capsaicin-response magnitudes. Interestingly, mithramycin-A also reduced the mRNA encoding Sp1 and Sp4 in DRG neurons, transcription factors previously found to positively regulate TRPV1 expression in sensory neurons. Taken together, we propose that mithramycin-A directs an inhibitory effect on a subpopulation of capsaicin-responsive DRG neurons that utilize Sp1-like factors for TRPV1 expression. Given the therapeutic correlate of mithramycin-A effectiveness in the treatment of certain cancers, small molecule transcriptional inhibitors such as mithramycin-A may serve as useful tools of discovery in pain transduction and possibly future analgesic development.
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Affiliation(s)
- K Zavala
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - J Lee
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - J Chong
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - M Sharma
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - H Eilers
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - M A Schumacher
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States.
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ZHAO YINGYING, ZHANG WENJING, GUO ZHENG, MA FENG, WU YAO, BAI YANG, GONG WEI, CHEN YE, CHENG TIANMING, ZHI FACHAO, ZHANG YALI, WANG JIDE, JIANG BO. Inhibition of the transcription factor Sp1 suppresses colon cancer stem cell growth and induces apoptosis in vitro and in nude mouse xenografts. Oncol Rep 2013; 30:1782-92. [DOI: 10.3892/or.2013.2627] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/02/2013] [Indexed: 11/06/2022] Open
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Wang SY, Lee YL, Lai YH, Chen JJW, Wu WL, Yuann JMP, Su WL, Chuang SM, Hou MH. Spermine attenuates the action of the DNA intercalator, actinomycin D, on DNA binding and the inhibition of transcription and DNA replication. PLoS One 2012; 7:e47101. [PMID: 23144800 PMCID: PMC3493566 DOI: 10.1371/journal.pone.0047101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 09/10/2012] [Indexed: 12/23/2022] Open
Abstract
The anticancer activity of DNA intercalators is related to their ability to intercalate into the DNA duplex with high affinity, thereby interfering with DNA replication and transcription. Polyamines (spermine in particular) are almost exclusively bound to nucleic acids and are involved in many cellular processes that require nucleic acids. Until now, the effects of polyamines on DNA intercalator activities have remained unclear because intercalation is the most important mechanism employed by DNA-binding drugs. Herein, using actinomycin D (ACTD) as a model, we have attempted to elucidate the effects of spermine on the action of ACTD, including its DNA-binding ability, RNA and DNA polymerase interference, and its role in the transcription and replication inhibition of ACTD within cells. We found that spermine interfered with the binding and stabilization of ACTD to DNA. The presence of increasing concentrations of spermine enhanced the transcriptional and replication activities of RNA and DNA polymerases, respectively, in vitro treated with ActD. Moreover, a decrease in intracellular polyamine concentrations stimulated by methylglyoxal-bis(guanylhydrazone) (MGBG) enhanced the ACTD-induced inhibition of c-myc transcription and DNA replication in several cancer cell lines. The results indicated that spermine attenuates ACTD binding to DNA and its inhibition of transcription and DNA replication both in vitro and within cells. Finally, a synergistic antiproliferative effect of MGBG and ACTD was observed in a cell viability assay. Our findings will be of significant relevance to future developments in combination with cancer therapy by enhancing the anticancer activity of DNA interactors through polyamine depletion.
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Affiliation(s)
- Sheng-Yu Wang
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Yueh-Luen Lee
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan
| | - Yi-Hua Lai
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Jeremy J. W. Chen
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Wen-Lin Wu
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Jeu-Ming P. Yuann
- Department of Biotechnology, Ming Chuan University, Taoyuan County, Taiwan
| | - Wang-Lin Su
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
| | - Show-Mei Chuang
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Ming-Hon Hou
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
- * E-mail:
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Hsu CW, Chuang SM, Wu WL, Hou MH. The crucial role of divalent metal ions in the DNA-acting efficacy and inhibition of the transcription of dimeric chromomycin A3. PLoS One 2012; 7:e43792. [PMID: 22984445 PMCID: PMC3440418 DOI: 10.1371/journal.pone.0043792] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 07/24/2012] [Indexed: 12/11/2022] Open
Abstract
Chromomycin A3 (Chro) is capable of forming a stable dimeric complex via chelation with Ni(II), Fe(II) and Co(II). According to the circular dichroism study, the dimer conformations are significantly different among the Fe(II)-, Co(II)-, and Ni(II)-containing dimeric Chro complexes; however, the dimer conformations were preserved at high temperatures. Furthermore, we conducted a systematic study to determine the effects of these divalent metal ions on the DNA-acting efficacy of dimeric Chro, including its DNA-binding affinity, DNA stabilization capacity, DNA cleavage activity, and the inhibition of transcription both in vitro and within cells. Kinetic analyses using surface plasmon resonance (SPR) showed that NiII(Chro)2 exhibited the highest Ka with a value of 1.26×107 M−1, which is approximately 1.6- and 3.7-fold higher than the Ka values obtained for CoII(Chro)2 and FeII(Chro)2, respectively. The Tm and ΔG values for the DNA duplex increased after the addition of drug complexes in the following order: NiII(Chro)2>CoII(Chro)2>FeII(Chro)2. In the DNA integrity assays, the DNA cleavage rate of CoII(Chro)2 (1.2×10−3 s−1) is higher than those of FeII(Chro)2 and NiII(Chro)2, which were calculated to be 1×10−4 and 3.1×10−4 s−1, respectively. Consistent with the SPR and UV melting results, NiII(Chro)2 possesses the highest inhibitory effect on in vitro transcription and c-myc transcription within cells compared to CoII(Chro)2 and FeII(Chro)2. By comparing the cytotoxicity among CoII(Chro)2, FeII(Chro)2, and NiII(Chro)2 to several cancer cell lines, our studies concluded that NiII(Chro)2 displayed more potential antitumor activities than CoII(Chro)2 and FeII(Chro)2 did due to its higher DNA-acting efficacy. Changes to the divalent metal ions in the dimeric Chro complexes have been correlated with improved anticancer profiles. The availability of new metal derivatives of Chro may introduce new possibilities for exploiting the unique properties of this class of compounds for therapeutic applications.
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Affiliation(s)
- Chun-Wei Hsu
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Show-Mei Chuang
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Wen-Ling Wu
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Ming-Hon Hou
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
- * E-mail:
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12
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Núñez LE, Nybo SE, González-Sabín J, Pérez M, Menéndez N, Braña AF, Shaaban KA, He M, Morís F, Salas JA, Rohr J, Méndez C. A novel mithramycin analogue with high antitumor activity and less toxicity generated by combinatorial biosynthesis. J Med Chem 2012; 55:5813-25. [PMID: 22578073 DOI: 10.1021/jm300234t] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mithramycin is an antitumor compound produced by Streptomyces argillaceus that has been used for the treatment of several types of tumors and hypercalcaemia processes. However, its use in humans has been limited because of its side effects. Using combinatorial biosynthesis approaches, we have generated seven new mithramycin derivatives, which differ from the parental compound in the sugar profile or in both the sugar profile and the 3-side chain. From these studies three novel derivatives were identified, demycarosyl-3D-β-d-digitoxosylmithramycin SK, demycarosylmithramycin SDK, and demycarosyl-3D-β-d-digitoxosylmithramycin SDK, which show high antitumor activity. The first one, which combines two structural features previously found to improve pharmacological behavior, was generated following two different strategies, and it showed less toxicity than mithramycin. Preliminary in vivo evaluation of its antitumor activity through hollow fiber assays, and in subcutaneous colon and melanoma cancers xenografts models, suggests that demycarosyl-3D-β-d-digitoxosylmithramycin SK could be a promising antitumor agent worthy of further investigation.
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Affiliation(s)
- Luz E Núñez
- Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A), Universidad de Oviedo, 33006 Oviedo, Spain
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13
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Capretto L, Mazzitelli S, Brognara E, Lampronti I, Carugo D, Hill M, Zhang X, Gambari R, Nastruzzi C. Mithramycin encapsulated in polymeric micelles by microfluidic technology as novel therapeutic protocol for beta-thalassemia. Int J Nanomedicine 2012; 7:307-24. [PMID: 22287841 PMCID: PMC3265999 DOI: 10.2147/ijn.s25657] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This report shows that the DNA-binding drug, mithramycin, can be efficiently encapsulated in polymeric micelles (PM-MTH), based on Pluronic® block copolymers, by a new microfluidic approach. The effect of different production parameters has been investigated for their effect on PM-MTH characteristics. The compared analysis of PM-MTH produced by microfluidic and conventional bulk mixing procedures revealed that microfluidics provides a useful platform for the production of PM-MTH with improved controllability, reproducibility, smaller size, and polydispersity. Finally, an investigation of the effects of PM-MTH, produced by microfluidic and conventional bulk mixing procedures, on the erythroid differentiation of both human erythroleukemia and human erythroid precursor cells is reported. It is demonstrated that PM-MTH exhibited a slightly lower toxicity and more pronounced differentiative activity when compared to the free drug. In addition, PM-MTH were able to upregulate preferentially γ-globin messenger ribonucleic acid production and to increase fetal hemoglobin (HbF) accumulation, the percentage of HbF-containing cells, and their HbF content without stimulating α-globin gene expression, which is responsible for the clinical symptoms of β-thalassemia. These results represent an important first step toward a potential clinical application, since an increase in HbF could alleviate the symptoms underlying β-thalassemia and sickle cell anemia. In conclusion, this report suggests that PM-MTH produced by microfluidic approach warrants further evaluation as a potential therapeutic protocol for β-thalassemia.
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Affiliation(s)
- Lorenzo Capretto
- Engineering Sciences, University of Southampton, Southampton, UK
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14
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Kuck D, Caulfield T, Lyko F, Medina-Franco JL. Nanaomycin A selectively inhibits DNMT3B and reactivates silenced tumor suppressor genes in human cancer cells. Mol Cancer Ther 2010; 9:3015-23. [PMID: 20833755 DOI: 10.1158/1535-7163.mct-10-0609] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Enzymes involved in the epigenetic regulation of the genome represent promising starting points for therapeutic intervention by small molecules, and DNA methyltransferases (DNMT) are emerging targets for the development of a new class of cancer therapeutics. In this work, we present nanaomycin A, initially identified by a virtual screening for inhibitors against DNMT1, as a compound inducing antiproliferative effects in three different tumor cell lines originating from different tissues. Nanaomycin A treatment reduced the global methylation levels in all three cell lines and reactivated transcription of the RASSF1A tumor suppressor gene. In biochemical assays, nanaomycin A revealed selectivity toward DNMT3B. To the best of our knowledge, this is the first DNMT3B-selective inhibitor identified to induce genomic demethylation. Our study thus establishes the possibility of selectively inhibiting individual DNMT enzymes.
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Affiliation(s)
- Dirk Kuck
- Division of Epigenetics, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg BW 69120, Germany.
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15
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Ghosh S, Majumder P, Pradhan SK, Dasgupta D. Mechanism of interaction of small transcription inhibitors with DNA in the context of chromatin and telomere. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:795-809. [PMID: 20638489 DOI: 10.1016/j.bbagrm.2010.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/23/2010] [Accepted: 06/30/2010] [Indexed: 01/13/2023]
Abstract
Small molecules from natural and synthetic sources have long been employed as human drugs. The transcription inhibitory potential of one class of these molecules has paved their use as anticancer drugs. The principal mode of action of these molecules is via reversible interaction with genomic DNA, double and multiple stranded. In this article we have revisited the mechanism of the interaction in the context of chromatin and telomere. The established modes of association of these molecules with double helical DNA provide a preliminary mechanism of their transcription inhibitory potential, but the scenario assumes a different dimension when the genomic DNA is associated with proteins in the transcription apparatus of both prokaryotic and eukaryotic organisms. We have discussed this altered scenario as a prelude to understand the chemical biology of their action in the cell. For the telomeric quadruplex DNA, we have reviewed the mechanism of their association with the quadruplex and resultant cellular consequence.
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Affiliation(s)
- Saptaparni Ghosh
- Biophysics Division, Saha Institute of Nuclear Physics, Sector-I, Block-AF, Bidhan Nagar, Kolkata Pin, 700064, India
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16
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Seznec J, Silkenstedt B, Naumann U. Therapeutic effects of the Sp1 inhibitor mithramycin A in glioblastoma. J Neurooncol 2010; 101:365-77. [PMID: 20556479 DOI: 10.1007/s11060-010-0266-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 05/30/2010] [Indexed: 02/03/2023]
Abstract
Mithramycin A (MitA) is a chemotherapeutic compound which has been used in the therapy of several types of cancer. For experimental cancer it has been shown that MitA mediates the expression of genes involved in tumor progression such as genes involved in immunosurveillance, cell motility or cell death. MitA works synergistically with Apo2L/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and with antiangiogenic agents. We were therefore interested in analyzing whether MitA might be a suitable agent for glioma therapy. We demonstrate herein that the cell death sensitizing effects of MitA are cell line specific, independent of the endogenous status of the tumor suppressor p53 as well as of the endogenous expression of X-linked inhibitor of apoptosis (XIAP) or basal sensitivity towards death ligand-induced cell death. In glioma cells, MitA reduced the secretion and activity of the migration-involved matrix metalloproteinases (MMP), diminished vascular endothelial growth factor (VEGF), and increased recepteur d'origine nantais (RON) kinase messenger RNA (mRNA), paralleled by a significant reduction of glioma cell migration. In contrast to other cancer types, in glioma cells MitA did not alter the expression of the immunorelevant genes major histocompatibility complex I class related (MIC)-A, MIC-B or UL16 binding proteins (ULBP). We conclude that, whereas MitA-mediated reduction of XIAP expression and sensitization to Apo2L/TRAIL are cell line specific, its antimigratory effects are more general and might be the result of altered expression of MMP, VEGF, and/or RON kinase. Therefore, MitA might be a potential agent to reduce glioma cell migration.
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Affiliation(s)
- Janina Seznec
- Laboratory of Molecular Neuro-Oncology, Department of General Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Str. 27, 72076, Tübingen, Germany
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Yang TP, Chiou HL, Maa MC, Wang CJ. Mithramycin inhibits human epithelial carcinoma cell proliferation and migration involving downregulation of Eps8 expression. Chem Biol Interact 2010; 183:181-6. [PMID: 19799886 DOI: 10.1016/j.cbi.2009.09.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 09/08/2009] [Accepted: 09/22/2009] [Indexed: 10/20/2022]
Abstract
Mithramycin is an inhibitor of the binding of the Sp-family transcription factor to the GC box. Many studies show that mithramycin may reduce the expression of many oncogenes by inhibiting the mRNA and protein synthesis and it has been used as an antibiotic chemotherapy drug for a long time. Recently, Eps8 (EGFR pathway substrate 8) has been revealed to be a novel proto-oncogene related to cellular transformation, Rac activation and actin barbed-end-capping activity. Therefore, the aim of this study was to verify whether Eps8 might be regulated by mithramycin. Results showed that mithramycin could reduce the mRNA and protein levels of Eps8 in dose- and time-dependent manners in several cancer cell lines. Furthermore, cell growth and migration ability were also reduced significantly by mithramycin treatment. Since Src is a well-known Eps8 activity enhancer, a v-Src transfected IV5 cell line was subjected to mithramycin treatment and then analyzed to show that Src expression was unable to restore the mithramycin-induced decrease in Eps8 expression, cell growth, and migration ability. To further confirm the above mentioned results, the expression of Eps8 was eliminated by a transient transfection with siRNA and subsequent analysis showed that silencing of Eps8 might also lead to a reduced growth and migration ability of cancer cells. These findings suggested that Eps8 was involved in the regulation of growth and motility of cancer cells and mithramycin might exert its anticancer ability via a pathway involving the downregulation of Eps8.
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Affiliation(s)
- Tzi-Peng Yang
- School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
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18
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Olano C, Méndez C, Salas JA. Antitumor compounds from actinomycetes: from gene clusters to new derivatives by combinatorial biosynthesis. Nat Prod Rep 2009; 26:628-60. [PMID: 19387499 DOI: 10.1039/b822528a] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Covering: up to October 2008. Antitumor compounds produced by actinomycetes and novel derivatives generated by combinatorial biosynthesis are reviewed (with 318 references cited.) The different structural groups for which the relevant gene clusters have been isolated and characterized are reviewed, with a description of the strategies used for the generation of the novel derivatives and the activities of these compounds against tumor cell lines.
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Affiliation(s)
- Carlos Olano
- Departamento de Biología Funcional and Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A.), Universidad de Oviedo, 33006, Oviedo, Spain
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19
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Liu D, Wei Y, Zhou F, Ge Y, Xu J, Chen H, Zhang W, Yun X, Jiang J. E1AF promotes mithramycin A-induced Huh-7 cell apoptosis depending on its DNA-binding domain. Arch Biochem Biophys 2008; 477:20-6. [PMID: 18510939 DOI: 10.1016/j.abb.2008.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/11/2008] [Accepted: 05/07/2008] [Indexed: 11/28/2022]
Abstract
Transcription factor E1AF is widely known to play critical roles in tumor metastasis via directly binding to the promoters of genes involved in tumor migration and invasion. Here, we reported for the first time the pro-apoptotic role of E1AF in tumor cells. The expression of E1AF at protein level was obviously increased during Huh-7 and Hep3B cells apoptosis induced by the anticancer agent mithramycin A. E1AF overexpression markedly enhanced mithramycin A-induced Huh-7 cell apoptosis and the expression of pro-apoptotic protein Bax depending on its DNA-binding domain. And, reduction of E1AF inhibited mithramycin A-induced Huh-7 cell apoptosis. Furthermore, reducing the expression of Bax significantly inhibited E1AF-increased Huh-7 cell apoptosis induced by mithramycin A. Taken together, E1AF increases mithramycin A-induced Huh-7 cells apoptosis and Bax expression depending on its DNA-binding domain, indicating that E1AF might contribute to the therapeutic efficiency of mithramycin A for hepatoma.
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Affiliation(s)
- Dan Liu
- Key Laboratory of Glycoconjugates Research, Ministry of Public Health & Gene Research Center, Shanghai Medical College of Fudan University, Dongan Road 130, Shanghai 200032, People's Republic of China
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20
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Lee TJ, Jung EM, Lee JT, Kim S, Park JW, Choi KS, Kwon TK. Mithramycin A sensitizes cancer cells to TRAIL-mediated apoptosis by down-regulation of XIAP gene promoter through Sp1 sites. Mol Cancer Ther 2007; 5:2737-46. [PMID: 17121920 DOI: 10.1158/1535-7163.mct-06-0426] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mithramycin A is a DNA-binding antitumor agent, which has been clinically used in the therapies of several types of cancer and Paget's disease. In this study, we investigated the combined effect of mithramycin A and tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) on apoptosis of cancer cells. In Caki renal cancer cells, which are resistant to TRAIL, cotreatment with subtoxic doses of mithramycin A and TRAIL resulted in a marked increase in apoptosis. This combined treatment was also cytotoxic to Caki cells overexpressing Bcl-2 but not to normal mesengial cells. Moreover, apoptosis by the combined treatment with mithramycin A and TRAIL was dramatically induced in various cancer cell types, thus offering an attractive strategy for safely treating malignant tumors. Mithramycin A-stimulated TRAIL-induced apoptosis was blocked by pretreatment with the broad caspase inhibitor zVAD-fmk or Crm-A overexpression, showing its dependence on caspases. We found that mithramycin A selectively down-regulated XIAP protein levels in various cancer cells. Luciferase reporter assay and the chromatin immunoprecipitation assay using the XIAP promoter constructs show that mithramycin A down-regulates the transcription of XIAP gene through inhibition of Sp1 binding to its promoter. Although XIAP overexpression significantly attenuated apoptosis induced by mithramycin A plus TRAIL, suppression of XIAP expression by transfection with its small interfering RNA prominently enhanced TRAIL-induced apoptosis. We present here for the first time that mithramycin A-induced suppression of XIAP transcription plays a critical role in the recovery of TRAIL sensitivity in various cancer cells.
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Affiliation(s)
- Tae-Jin Lee
- Department of Immunology, School of Medicine, Keimyung University, 194 DongSan-Dong Jung-Gu, Taegu 700-712, South Korea
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21
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Lombó F, Menéndez N, Salas JA, Méndez C. The aureolic acid family of antitumor compounds: structure, mode of action, biosynthesis, and novel derivatives. Appl Microbiol Biotechnol 2006; 73:1-14. [PMID: 17013601 DOI: 10.1007/s00253-006-0511-6] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 05/15/2006] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
Members of the aureolic acid family are tricyclic polyketides with antitumor activity which are produced by different streptomycete species. These members are glycosylated compounds with two oligosaccharide chains of variable sugar length. They interact with the DNA minor groove in high-GC-content regions in a nonintercalative way and with a requirement for magnesium ions. Mithramycin and chromomycins are the most representative members of the family, mithramycin being used as a chemotherapeutic agent for the treatment of several cancer diseases. For chromomycin and durhamycin A, antiviral activity has also been reported. The biosynthesis gene clusters for mithramycin and chromomycin A(3) have been studied in detail by gene sequencing, insertional inactivation, and gene expression. Most of the biosynthetic intermediates in these pathways have been isolated and characterized. Some of these compounds showed an increase in antitumor activity in comparison with the parent compounds. A common step in the biosynthesis of all members of the family is the formation of the tetracyclic intermediate premithramycinone. Further biosynthetic steps (glycosylation, methylations, acylations) proceed through tetracyclic intermediates which are finally converted into tricyclic compounds by the action of a monooxygenase, a key event for the biological activity. Heterologous expression of biosynthetic genes from other aromatic polyketide pathways in the mithramycin producer (or some mutants) led to the isolation of novel hybrid compounds.
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Affiliation(s)
- Felipe Lombó
- Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A), Universidad de Oviedo, 33006, Oviedo, Spain
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22
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Leroy I, Laurent G, Quillet-Mary A. Mithramycin A activates Fas death pathway in leukemic cell lines. Apoptosis 2006; 11:113-9. [PMID: 16374547 DOI: 10.1007/s10495-005-3089-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Mithramycin A (MMA, trade name Plicamycin) can facilitate TNFalpha- (Tumor Necrosis Factor) and Fas ligand-induced apoptosis. Besides, several drugs play their anticancer effect through Fas apoptotic pathway. So we investigated the effect of MMA on Fas signaling. In this study we show that MMA induces apoptosis in Fas sensitive Jurkat cells and Fas resistant KG1a cells. This effect involves Fas apoptotic pathway: cell exposure to MMA leads to Fas clustering at the cell surface, DISC (Death Inducing Signaling Complex) formation and caspase cleavage. This phenomenon is independent of Fas ligand/Fas interaction and blockade of Fas death pathway partially inhibits MMA-induced apoptosis. Moreover the activation of Fas apoptotic pathway by MMA is correlated to the modulation of c-Flip(L) expression. Finally, pre-treatment with sub-lethal doses of MMA sensitizes KG1a cells to chemotherapeutic agents. Thus all these results may have important implications to improve clinical treatments.
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Affiliation(s)
- I Leroy
- INSERM U563/CPTP, Toulouse, France
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23
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Brouland JP, Gélébart P, Kovàcs T, Enouf J, Grossmann J, Papp B. The loss of sarco/endoplasmic reticulum calcium transport ATPase 3 expression is an early event during the multistep process of colon carcinogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:233-42. [PMID: 15972967 PMCID: PMC1603437 DOI: 10.1016/s0002-9440(10)62968-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Calcium accumulation in the endoplasmic reticulum is accomplished by sarco/endoplasmic reticulum calcium transport ATPases (SERCA enzymes). To better characterize the role of SERCA3 in colon carcinogenesis, its expression has been investigated in colonic epithelium, benign lesions, adenomas, and adenocarcinomas. In addition, the regulation of SERCA3 expression was analyzed in the context of the adenomatous polyposis coli/beta-catenin/T-cell factor 4 (TCF4) pathway and of specificity protein 1 (Sp1)-like factor-dependent transcription. We report that SERCA3 expression increased along the crypts as cells differentiated in normal colonic mucosa and in hyperplastic polyps, was moderately and heterogeneously expressed in colonic adenomas with expression levels inversely correlated with the degree of dysplasia, was barely detectable in well and moderately differentiated adenocarcinomas, and was absent in poorly differentiated tumors. Inhibition of Sp1-like factor-dependent transcription blocked SERCA3 expression during cell differentiation, and SERCA3 expression was induced by the expression of dominant-negative TCF4 in colon cancer cells. These data link SERCA3 expression to the state of differentiation of colonic epithelial cells, and relate SERCA3 expression, already decreased in adenomas, to enhanced adenomatous polyposis coli/beta-catenin/TCF4-dependent signaling and deficient Sp1-like factor-dependent transcription. In conclusion, intracellular calcium homeostasis becomes progressively anomalous during colon carcinogenesis as reflected by deficient SERCA3 expression.
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Sandorfi N, Louneva N, Hitraya E, Hajnoczky G, Saitta B, Jimenez SA. Inhibition of collagen gene expression in systemic sclerosis dermal fibroblasts by mithramycin. Ann Rheum Dis 2005; 64:1685-91. [PMID: 15901633 PMCID: PMC1755322 DOI: 10.1136/ard.2005.037515] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The anti-tumour antibiotic mithramycin is also a potent inhibitor of fibrosis after glaucoma surgery. This drug displays high affinity binding to GC-rich sequences in DNA, including those present in the promoter of the gene encoding the alpha1 chain of type I collagen (COL1A1). OBJECTIVE To evaluate the effects of mithramycin on COL1A1 expression in systemic sclerosis fibroblasts. METHODS Confluent cultures of dermal fibroblasts from patients with recent onset diffuse systemic sclerosis were treated with mithramycin in vitro. Cell viability and protein expression were examined by fluorescence and confocal imaging. Type I collagen production was analysed by confocal imaging and metabolic labelling. COL1A1 messenger RNA levels and stability were assessed by northern hybridisation, and COL1A1 transcription was examined by transient transfections. RESULTS Treatment of systemic sclerosis fibroblasts with mithramycin (10-100 nmol/l) did not cause significant cytotoxicity. Type I collagen biosynthesis decreased by 33-40% and 50-70% in cells cultured with mithramycin at 10 nmol/l and 100 nmol/l, respectively. Mithramycin at 50 nmol/l decreased COL1A1 mRNA levels by 40-60%. The effects of mithramycin on collagen gene expression were mediated by transcriptional and post-transcriptional mechanisms as shown by the reduction of COL1A1 promoter activity and by a decrease in the stability of these transcripts, respectively. CONCLUSIONS Mithramycin causes potent inhibition of collagen production and gene expression in systemic sclerosis dermal fibroblasts in vitro in the absence of cytotoxic effects. These results suggest that this drug may be an effective treatment for the fibrotic process which is the hallmark of systemic sclerosis.
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Affiliation(s)
- N Sandorfi
- Division of Rheumatology, Department of medicine, Thomas Jefferson University, Philadelphia, PA 19107-5041, USA
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25
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Abstract
Although most antibiotics do not need metal ions for their biological activities, there are a number of antibiotics that require metal ions to function properly, such as bleomycin (BLM), streptonigrin (SN), and bacitracin. The coordinated metal ions in these antibiotics play an important role in maintaining proper structure and/or function of these antibiotics. Removal of the metal ions from these antibiotics can cause changes in structure and/or function of these antibiotics. Similar to the case of "metalloproteins," these antibiotics are dubbed "metalloantibiotics" which are the title subjects of this review. Metalloantibiotics can interact with several different kinds of biomolecules, including DNA, RNA, proteins, receptors, and lipids, rendering their unique and specific bioactivities. In addition to the microbial-originated metalloantibiotics, many metalloantibiotic derivatives and metal complexes of synthetic ligands also show antibacterial, antiviral, and anti-neoplastic activities which are also briefly discussed to provide a broad sense of the term "metalloantibiotics."
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Affiliation(s)
- Li-June Ming
- Department of Chemistry and Institute for Biomolecular Science, University of South Florida, Tampa, Florida 33620-5250, USA.
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26
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Nag A, Datta A, Yoo K, Bhattacharyya D, Chakrabortty A, Wang X, Slagle BL, Costa RH, Raychaudhuri P. DDB2 induces nuclear accumulation of the hepatitis B virus X protein independently of binding to DDB1. J Virol 2001; 75:10383-92. [PMID: 11581406 PMCID: PMC114612 DOI: 10.1128/jvi.75.21.10383-10392.2001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2001] [Accepted: 07/30/2001] [Indexed: 02/06/2023] Open
Abstract
The hepatitis B virus (HBV) X protein (HBx) is critical for the life cycle of the virus. HBx associates with several host cell proteins including the DDB1 subunit of the damaged-DNA binding protein DDB. Recent studies on the X protein encoded by the woodchuck hepadnavirus have provided correlative evidence indicating that the interaction with DDB1 is important for establishment of infection by the virus. In addition, the interaction with DDB1 has been implicated in the nuclear localization of HBx. Because the DDB2 subunit of DDB is required for the nuclear accumulation of DDB1, we investigated the role of DDB2 in the nuclear accumulation of HBx. Here we show that expression of DDB2 increases the nuclear levels of HBx. Several C-terminal deletion mutants of DDB2 that fail to bind DDB1 are able to associate with HBx, suggesting that DDB2 may associate with HBx independently of binding to DDB1. We also show that DDB2 enhances the nuclear accumulation of HBx independently of binding to DDB1, since a mutant that does not bind DDB1 is able to enhance the nuclear accumulation of HBx. HBV infection is associated with liver pathogenesis. We show that the nuclear levels of DDB1 and DDB2 are tightly regulated in hepatocytes. Studies with regenerating mouse liver indicate that during late G1 phase the nuclear levels of both subunits of DDB are transiently increased, followed by a sharp decrease in S phase. Taken together, these results suggest that DDB1 and DDB2 would participate in the nuclear functions of HBx effectively only during the late-G1 phase of the cell cycle.
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Affiliation(s)
- A Nag
- Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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27
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Bradham CA, Hatano E, Brenner DA. Dominant-negative TAK1 induces c-Myc and G(0) exit in liver. Am J Physiol Gastrointest Liver Physiol 2001; 281:G1279-89. [PMID: 11668037 DOI: 10.1152/ajpgi.2001.281.5.g1279] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transforming growth factor-beta (TGF-beta)-activated kinase 1 (TAK1), a serine/threonine kinase, is reported to function in the signaling pathways of TGF-beta, interleukin 1, and ceramide. However, the physiological role of TAK1 in vivo is largely unknown. To assess the function of TAK1 in vivo, dominant-negative TAK1 (dnTAK1) was expressed in the rat liver by adenoviral gene transfer. dnTAK1 expression abrogated c-Jun NH(2)-terminal kinase and c-Jun but not nuclear factor (NF)-kappaB or SMAD activation after partial hepatectomy (PH). Expression of dnTAK1 or TAM-67, a dominant-negative c-Jun, induced G(0) exit in quiescent liver and accelerated cell cycle progression after PH. Finally, dnTAK1 and TAM-67 induced c-myc expression in the liver before and after PH, suggesting that G(0) exit induced by dnTAK1 and TAM-67 is mediated by c-myc induction.
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Affiliation(s)
- C A Bradham
- Department of Medicine, University of North Carolina at Chapel Hill, 27707, USA
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Torrance CJ, Agrawal V, Vogelstein B, Kinzler KW. Use of isogenic human cancer cells for high-throughput screening and drug discovery. Nat Biotechnol 2001; 19:940-5. [PMID: 11581659 DOI: 10.1038/nbt1001-940] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell-based screening for novel tumor-specific drugs has been compromised by the lack of appropriate control cells. We describe a strategy for drug screening based on isogenic human cancer cell lines in which key tumorigenic genes have been deleted by targeted homologous recombination. As a test case, a yellow fluorescent protein (YFP) expression vector was introduced into the colon cancer cell line DLD-1, and a blue fluorescent protein (BFP) expression vector was introduced into an isogenic derivative in which the mutant K-Ras allele had been deleted. Co-culture of both cell lines allowed facile screening for compounds with selective toxicity toward the mutant Ras genotype. Among 30,000 compounds screened, a novel cytidine nucleoside analog was identified that displayed selective activity in vitro and inhibited tumor xenografts containing mutant Ras. The present data demonstrate a broadly applicable approach for mining therapeutic agents targeted to the specific genetic alterations responsible for cancer development.
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Affiliation(s)
- C J Torrance
- The Howard Hughes Medical Institute, 1650 Orleans Street, Baltimore, MD 21231, USA
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Affiliation(s)
- J O Trent
- James Graham Brown Cancer Center, Department of Medicine, University of Louisville, Louisville, Kentucky 40202, USA
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Chen SJ, Chen YF, Miller DM, Li H, Oparil S. Mithramycin inhibits myointimal proliferation after balloon injury of the rat carotid artery in vivo. Circulation 1994; 90:2468-73. [PMID: 7955204 DOI: 10.1161/01.cir.90.5.2468] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Smooth muscle proliferation and extracellular matrix formation in the subintimal region of blood vessels that have been subjected to intimal injury are responsible for restenosis following balloon angioplasty of the coronary arteries and for accelerated atherosclerosis in a variety of other pathophysiological states. The immediate early-response gene c-myc is overexpressed in proliferating vascular smooth muscle cells in vitro, and c-myc antisense oligomers have been shown to reduce c-myc expression and to inhibit proliferation of vascular smooth muscle cells in culture. Mithramycin is a commercially available G-C-specific DNA binding drug that selectively inhibits transcription of genes, such as c-myc, that have G-C-rich promoter sequences. This study tested the hypothesis that mithramycin inhibits transcription of the c-myc proto-oncogene and prevents myointimal proliferation after balloon injury of the rat carotid artery in vivo. METHODS AND RESULTS Ten-week-old male Sprague-Dawley rats received mithramycin (150 micrograms/kg IP) or distilled H2O 1 hour before and 1 hour after balloon injury of the right common carotid artery. After 2 weeks, the rats were killed by overdose of pentobarbital, and the injured right and uninjured control left arteries were pressure-fixed and subjected to morphological analysis for evaluation of the degree of myointimal thickening. Separate groups of rats were killed at 2 and 6 hours after vascular injury, and total RNA from injured and control vessels of mithramycin- and vehicle-treated rats was subjected to Northern analysis for assessment of steady-state c-myc mRNA levels. The areas of neointima and the ratios of neointimal to medial area were significantly less in mithramycin-treated than in control rats (0.6 +/- 0.1 versus 1.2 +/- 0.1 mm2, P < .01 and 95 +/- 16% versus 190 +/- 14%, P < .01). Lumen size was significantly greater in mithramycin-treated than in control rats (1.5 +/- 0.1 versus 0.8 +/- 0.1 mm2, P < .01). Steady-state c-myc mRNA levels were increased 10-fold and 2-fold (compared with undamaged carotid arteries) at 2 and 6 hours after balloon injury, respectively; mithramycin treatment reduced c-myc mRNA levels at 2 and 6 hours by 66% and 53%, respectively. CONCLUSIONS These results support the hypothesis that systemic administration of mithramycin immediately (1 hour before and after intervention effectively inhibits transcription of the c-myc proto-oncogene and prevents myointimal proliferation after balloon injury of the rat carotid artery in vivo. Because mithramycin has been shown to be well tolerated by humans and to effectively inhibit transcription of c-myc in proliferating human cells, this agent may be useful in the prevention of coronary restenosis.
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Affiliation(s)
- S J Chen
- Department of Medicine, University of Alabama at Birmingham
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