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Cooper I, Atrakchi D, Walker MD, Horovitz A, Fridkin M, Shechter Y. Converting bleomycin into a prodrug that undergoes spontaneous reactivation under physiological conditions. Toxicol Appl Pharmacol 2019; 384:114782. [PMID: 31655077 DOI: 10.1016/j.taap.2019.114782] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 11/24/2022]
Abstract
Bleomycin is an anticancer antibiotic effective against a range of human malignancies. Yet its usefulness is limited by serious side effects. In this study, we converted bleomycin into a prodrug by covalently linking 2-sulfo, 9 fluorenylmethoxycarbonyl (FMS) to the primary amino side chain of bleomycin. FMS-bleomycin lost its efficacy to bind transition metal ions and therefore was converted into an inactive derivative. Upon incubation in vitro under physiological conditions, the FMS-moiety undergoes spontaneous hydrolysis, generating native bleomycin possessing full anti-bacterial potency. FMS hydrolysis and reactivation takes place with a t1/2 value of 17 ± 1 h. In silico simulation predicts a narrow therapeutic window in human patients of seven hours, starting 40 min after administration. In mice, close agreement was obtained between the experimental and the simulated pharmacokinetic profiles for FMS-bleomycin. FMS-bleomycin is thus shown to be a classical prodrug: it is inactive at the time of administration and the non-modified (active) bleomycin is released with a desirable pharmacokinetic profile following administration, suggesting it may have therapeutic value in the clinic.
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Affiliation(s)
- Itzik Cooper
- The Joseph Sagol Neuroscience Center, Sheba Medical Center Tel Hashomer, Ramat Gan 52621, Israel.
| | - Dana Atrakchi
- The Joseph Sagol Neuroscience Center, Sheba Medical Center Tel Hashomer, Ramat Gan 52621, Israel
| | - Michael D Walker
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Amnon Horovitz
- Department of Structural Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mati Fridkin
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yoram Shechter
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
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2
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Murray V, Chen JK, Yang D, Shen B. The genome-wide sequence specificity of DNA cleavage by bleomycin analogues in human cells. Bioorg Med Chem 2018; 26:4168-4178. [PMID: 30006142 DOI: 10.1016/j.bmc.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/26/2018] [Accepted: 07/04/2018] [Indexed: 02/06/2023]
Abstract
Bleomycin (BLM) is a cancer chemotherapeutic agent that cleaves cellular DNA at specific sequences. Using next-generation Illumina sequencing, the genome-wide sequence specificity of DNA cleavage by two BLM analogues, 6'-deoxy-BLM Z and zorbamycin (ZBM), was determined in human HeLa cells and compared with BLM. Over 200 million double-strand breaks were examined for each sample, and the 50,000 highest intensity cleavage sites were analysed. It was found that the DNA sequence specificity of the BLM analogues in human cells was different to BLM, especially at the cleavage site (position "0") and the "+1" position. In human cells, the 6'-deoxy-BLM Z had a preference for 5'-GTGY*MC (where * is the cleavage site, Y is C or T, M is A or C); it was 5'-GTGY*MCA for ZBM; and 5'-GTGT*AC for BLM. With cellular DNA, the highest ranked tetranucleotides were 5'-TGC*C and 5'-TGT*A for 6'-deoxy-BLM Z; 5'-TGC*C, 5'-TGT*A and 5'-TGC*A for ZBM; and 5'-TGT*A for BLM. In purified human genomic DNA, the DNA sequence preference was 5'-TGT*A for 6'-deoxy-BLM, 5'-RTGY*AYR (where R is G or A) for ZBM, and 5'-TGT*A for BLM. Thus, the sequence specificity of the BLM analogue, 6'-deoxy-BLM Z, was similar to BLM in purified human DNA, while ZBM was different.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Dong Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Ben Shen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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3
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Murray V, Chen JK, Chung LH. The Interaction of the Metallo-Glycopeptide Anti-Tumour Drug Bleomycin with DNA. Int J Mol Sci 2018; 19:E1372. [PMID: 29734689 PMCID: PMC5983701 DOI: 10.3390/ijms19051372] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 11/17/2022] Open
Abstract
The cancer chemotherapeutic drug, bleomycin, is clinically used to treat several neoplasms including testicular and ovarian cancers. Bleomycin is a metallo-glycopeptide antibiotic that requires a transition metal ion, usually Fe(II), for activity. In this review, the properties of bleomycin are examined, especially the interaction of bleomycin with DNA. A Fe(II)-bleomycin complex is capable of DNA cleavage and this process is thought to be the major determinant for the cytotoxicity of bleomycin. The DNA sequence specificity of bleomycin cleavage is found to at 5′-GT* and 5′-GC* dinucleotides (where * indicates the cleaved nucleotide). Using next-generation DNA sequencing, over 200 million double-strand breaks were analysed, and an expanded bleomycin sequence specificity was found to be 5′-RTGT*AY (where R is G or A and Y is T or C) in cellular DNA and 5′-TGT*AT in purified DNA. The different environment of cellular DNA compared to purified DNA was proposed to be responsible for the difference. A number of bleomycin analogues have been examined and their interaction with DNA is also discussed. In particular, the production of bleomycin analogues via genetic manipulation of the modular non-ribosomal peptide synthetases and polyketide synthases in the bleomycin gene cluster is reviewed. The prospects for the synthesis of bleomycin analogues with increased effectiveness as cancer chemotherapeutic agents is also explored.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Long H Chung
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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4
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Gautam SD, Chen JK, Murray V. The DNA sequence specificity of bleomycin cleavage in a systematically altered DNA sequence. J Biol Inorg Chem 2017; 22:881-892. [PMID: 28509989 DOI: 10.1007/s00775-017-1466-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/11/2017] [Indexed: 12/20/2022]
Abstract
Bleomycin is an anti-tumour agent that is clinically used to treat several types of cancers. Bleomycin cleaves DNA at specific DNA sequences and recent genome-wide DNA sequencing specificity data indicated that the sequence 5'-RTGT*AY (where T* is the site of bleomycin cleavage, R is G/A and Y is T/C) is preferentially cleaved by bleomycin in human cells. Based on this DNA sequence, we constructed a plasmid clone to explore this bleomycin cleavage preference. By systematic variation of single nucleotides in the 5'-RTGT*AY sequence, we were able to investigate the effect of nucleotide changes on bleomycin cleavage efficiency. We observed that the preferred consensus DNA sequence for bleomycin cleavage in the plasmid clone was 5'-YYGT*AW (where W is A/T). The most highly cleaved sequence was 5'-TCGT*AT and, in fact, the seven most highly cleaved sequences conformed to the consensus sequence 5'-YYGT*AW. A comparison with genome-wide results was also performed and while the core sequence was similar in both environments, the surrounding nucleotides were different.
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Affiliation(s)
- Shweta D Gautam
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
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5
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Bleomycin analogues preferentially cleave at the transcription start sites of actively transcribed genes in human cells. Int J Biochem Cell Biol 2017; 85:56-65. [PMID: 28167289 DOI: 10.1016/j.biocel.2017.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 01/23/2023]
Abstract
Bleomycin (BLM) is a cancer chemotherapeutic agent that is used in the treatment of several types of tumours. The cytotoxicity of three BLM analogues, BLM Z, 6'-deoxy-BLM Z and zorbamycin (ZBM), was determined in human HeLa cells in comparison with BLM. It was found that the IC50 values were 2.9μM for 6'-deoxy-BLM Z, 3.2μM for BLM Z, 4.4μM for BLM and 7.9μM for ZBM in HeLa cells. Using next-generation Illumina DNA sequencing techniques, the genome-wide cleavage of DNA by the BLM analogues was determined in human HeLa cells and compared with BLM. It was ascertained that BLM, 6'-deoxy-BLM Z and ZBM preferentially cleaved at the transcription start sites of actively transcribed genes in human cells. The degree of preferential cleavage at the transcription start sites was quantified and an inverse correlation with the IC50 values was observed. This indicated that the degree of preferential cleavage at transcription start sites is an important component in determining the cytotoxicity of BLM analogues.
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6
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Murray V, Chen JK, Tanaka MM. The genome-wide DNA sequence specificity of the anti-tumour drug bleomycin in human cells. Mol Biol Rep 2016; 43:639-51. [PMID: 27188426 DOI: 10.1007/s11033-016-3998-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/04/2016] [Indexed: 12/24/2022]
Abstract
The cancer chemotherapeutic agent, bleomycin, cleaves DNA at specific sites. For the first time, the genome-wide DNA sequence specificity of bleomycin breakage was determined in human cells. Utilising Illumina next-generation DNA sequencing techniques, over 200 million bleomycin cleavage sites were examined to elucidate the bleomycin genome-wide DNA selectivity. The genome-wide bleomycin cleavage data were analysed by four different methods to determine the cellular DNA sequence specificity of bleomycin strand breakage. For the most highly cleaved DNA sequences, the preferred site of bleomycin breakage was at 5'-GT* dinucleotide sequences (where the asterisk indicates the bleomycin cleavage site), with lesser cleavage at 5'-GC* dinucleotides. This investigation also determined longer bleomycin cleavage sequences, with preferred cleavage at 5'-GT*A and 5'- TGT* trinucleotide sequences, and 5'-TGT*A tetranucleotides. For cellular DNA, the hexanucleotide DNA sequence 5'-RTGT*AY (where R is a purine and Y is a pyrimidine) was the most highly cleaved DNA sequence. It was striking that alternating purine-pyrimidine sequences were highly cleaved by bleomycin. The highest intensity cleavage sites in cellular and purified DNA were very similar although there were some minor differences. Statistical nucleotide frequency analysis indicated a G nucleotide was present at the -3 position (relative to the cleavage site) in cellular DNA but was absent in purified DNA.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Mark M Tanaka
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
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7
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Chen JK, Murray V. The determination of the DNA sequence specificity of bleomycin-induced abasic sites. J Biol Inorg Chem 2016; 21:395-406. [PMID: 26940956 DOI: 10.1007/s00775-016-1349-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/22/2016] [Indexed: 12/20/2022]
Abstract
The DNA sequence specificity of the cancer chemotherapeutic agent, bleomycin, was determined with high precision in purified plasmid DNA using an improved technique. This improved technique involved the labelling of the 5'- and 3'-ends of DNA with different fluorescent tags, followed by simultaneous cleavage by bleomycin and capillary electrophoresis with laser-induced fluorescence. This permitted the determination of bleomycin cleavage specificity with high accuracy since end-label bias was greatly reduced. Bleomycin produces single- and double-strand breaks, abasic sites and other base damage in DNA. This high-precision method was utilised to elucidate, for the first time, the DNA sequence specificity of bleomycin-induced DNA damage at abasic sites. This was accomplished using endonuclease IV that cleaves DNA at abasic sites after bleomycin damage. It was found that bleomycin-induced abasic sites formed at 5'-GC and 5'-GT sites while bleomycin-induced phosphodiester strand breaks formed mainly at 5'-GT dinucleotides. Since bleomycin-induced abasic sites are produced in the absence of molecular oxygen, this difference in DNA sequence specificity could be important in hypoxic tumour cells.
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Affiliation(s)
- Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
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8
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Chung LH, Murray V. The mitochondrial DNA sequence specificity of the anti-tumour drug bleomycin using end-labeled DNA and capillary electrophoresis and a comparison with genome-wide DNA sequencing. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1008:87-97. [DOI: 10.1016/j.jchromb.2015.11.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 11/17/2015] [Accepted: 11/17/2015] [Indexed: 11/30/2022]
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Murray V, Chen JK, Galea AM. Enhanced DNA repair of bleomycin-induced 3'-phosphoglycolate termini at the transcription start sites of actively transcribed genes in human cells. Mutat Res 2014; 769:93-9. [PMID: 25771728 DOI: 10.1016/j.mrfmmm.2014.06.006] [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: 01/13/2014] [Revised: 05/29/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
The anti-tumour agent, bleomycin, cleaves DNA to give 3'-phosphoglycolate and 5'-phosphate termini. The removal of 3'-phosphoglycolate to give 3'-OH ends is a very important step in the DNA repair of these lesions. In this study, next-generation DNA sequencing was utilised to investigate the repair of these 3'-phosphoglycolate termini at the transcription start sites (TSSs) of genes in HeLa cells. The 143,600 identified human TSSs in HeLa cells comprised 82,596 non-transcribed genes and 61,004 transcribed genes; and the transcribed genes were divided into quintiles of 12,201 genes comprising the top 20%, 20-40%, 40-60%, 60-80%, 80-100% of expressed genes. Repair of bleomycin-induced 3'-phosphoglycolate termini was enhanced at actively transcribed genes. The top 20% and 20-40% quintiles had a very similar level of enhanced repair, the 40-60% quintile was intermediate, while the 60-80% and 80-100% quintiles were close to the low level of enhancement found in non-transcribed genes. There were also interesting differences regarding bleomycin repair on the sense and antisense strands of DNA at TSSs. The sense strand had highly enhanced repair between 0 and 250bp relative to the TSS, while for the antisense strand highly enhanced repair was between 150 and 450bp. Repair of DNA damage is a major mechanism of resistance to anti-tumour drugs and this study provides an insight into this process in human tumour cells.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Anne M Galea
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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10
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Murray V, Chen JK, Galea AM. The anti-tumor drug bleomycin preferentially cleaves at the transcription start sites of actively transcribed genes in human cells. Cell Mol Life Sci 2014; 71:1505-12. [PMID: 23982755 PMCID: PMC11113418 DOI: 10.1007/s00018-013-1456-4] [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: 06/02/2013] [Revised: 08/06/2013] [Accepted: 08/12/2013] [Indexed: 11/26/2022]
Abstract
The genome-wide pattern of DNA cleavage at transcription start sites (TSSs) for the anti-tumor drug bleomycin was examined in human HeLa cells using next-generation DNA sequencing. It was found that actively transcribed genes were preferentially cleaved compared with non-transcribed genes. The 143,600 identified human TSSs were split into non-transcribed genes (82,596) and transcribed genes (61,004) for HeLa cells. These transcribed genes were further split into quintiles of 12,201 genes comprising the top 20, 20-40, 40-60, 60-80, and 80-100 % of expressed genes. The bleomycin cleavage pattern at highly transcribed gene TSSs was greatly enhanced compared with purified DNA and non-transcribed gene TSSs. The top 20 and 20-40 % quintiles had a very similar enhanced cleavage pattern, the 40-60 % quintile was intermediate, while the 60-80 and 80-100 % quintiles were close to the non-transcribed and purified DNA profiles. The pattern of bleomycin enhanced cleavage had peaks that were approximately 200 bp apart, and this indicated that bleomycin was identifying the presence of phased nucleosomes at TSSs. Hence bleomycin can be utilized to detect chromatin structures that are present at actively transcribed genes. In this study, for the first time, the pattern of DNA damage by a clinically utilized cancer chemotherapeutic agent was performed on a human genome-wide scale at the nucleotide level.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia,
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Nguyen TV, Chen JK, Murray V. Bleomycin DNA damage: Anomalous mobility of 3'-phosphoglycolate termini in an automated capillary DNA sequencer. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 913-914:113-22. [PMID: 23277328 DOI: 10.1016/j.jchromb.2012.11.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/20/2012] [Accepted: 11/27/2012] [Indexed: 01/22/2023]
Abstract
An automated capillary DNA sequencer with laser-induced fluorescence detection can be utilised for DNA fragment analysis. The precise mobilities of DNA fragments with different chemical termini are especially important in the determination of the sequence specificity of DNA damaging agents. The aim of this study was to examine the electrophoretic mobility profile of DNA fragments with different 3'-termini. The nature of the 3'-teminal residue was found to have a major effect on the electrophoretic mobility of the DNA fragment, especially for 3'-phosphoglycolate termini that migrated anomalously by 3-6 nucleotides. Using the automated capillary sequencer, the electrophoretic mobilities of DNA fragments with different 3'-termini including 3'-hydrogen, 3'-hydroxyl, 3'-phosphate, and 3'-phosphoglycolate were extensively quantified and compared relative to each other. The 3'-hydrogen termini were generated by dideoxy sequencing; 3'-hydroxyl ends by minus sequencing; 3'-phosphate by Maxam-Gilbert chemical sequencing; and 3'-phosphoglycolate by bleomycin cleavage. The mobilities of these DNA fragments with different 3'-termini were found to be: (slowest) 3'-hydroxyl<3'-hydrogen<3'-phosphate<3'-phosphoglycolate (fastest); with average relative mobilities of 0.00<0.12<0.63<4.42 nucleotides, respectively. The possible causes of the unusual electrophoretic mobility of the 3'-phosphoglycolate termini were discussed.
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Affiliation(s)
- Trung V Nguyen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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12
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The DNA sequence specificity of bleomycin cleavage in telomeric sequences in human cells. J Biol Inorg Chem 2012; 17:1209-15. [DOI: 10.1007/s00775-012-0934-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/18/2012] [Indexed: 01/02/2023]
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Nguyen TV, Murray V. Human telomeric DNA sequences are a major target for the antitumour drug bleomycin. J Biol Inorg Chem 2011; 17:1-9. [PMID: 21761251 DOI: 10.1007/s00775-011-0818-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/27/2011] [Indexed: 10/18/2022]
Abstract
The DNA sequence specificity of the cancer chemotherapeutic agent bleomycin was examined in a human telomeric DNA sequence and compared with that of non-telomeric sequences. The target DNA sequence contained 17 repeats of the human telomeric sequence and other primary sites of bleomycin cleavage. The 377-base-pair target DNA was fluorescently labelled at the 3'-end, damaged with bleomycin and electrophoresed in an ABI 3730 automated capillary sequencer to determine the intensity and sequence specificity of bleomycin damage. The results revealed that bleomycin cleaved primarily at 5'-GT in the telomeric sequence 5'-GGGTTA. Maxam-Gilbert chemical sequencing reactions were utilised as DNA size markers to determine the precise sites of bleomycin cleavage. The telomeric region contained strong sites of bleomycin cleavage and constituted 57% of the 30 most intense bleomycin damage sites in the DNA sequence examined. These data indicated that telomeric DNA sequences are a major site for bleomycin damage.
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Affiliation(s)
- Trung V Nguyen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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Ma J, Jones SH, Hecht SM. A coumarin from Mallotus resinosus that mediates DNA cleavage. JOURNAL OF NATURAL PRODUCTS 2004; 67:1614-1616. [PMID: 15387675 DOI: 10.1021/np040129c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A crude extract prepared from roots of Mallotus resinosus exhibited significant Cu(2+)-dependent DNA strand scission activity and was thus selected for bioassay-guided fractionation. Scopoletin (1), a simple coumarin, was identified as the active principle responsible for DNA cleavage activity of the crude extract. The DNA strand scission activity of 1, as well as that of three structural analogues, is reported.
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Affiliation(s)
- Ji Ma
- Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia 22901, USA
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15
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Hecht SM. Bleomycin: new perspectives on the mechanism of action. JOURNAL OF NATURAL PRODUCTS 2000; 63:158-168. [PMID: 10650103 DOI: 10.1021/np990549f] [Citation(s) in RCA: 409] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The bleomycin group antitumor antibiotics have long been of interest as a consequence of their efficacy in the treatment of certain tumors, not to mention their unique structures and properties in mediating dioxygen activation and sequence selective degradation of DNA. At a chemical level, the structure originally assigned to bleomycin was subsequently reassigned and the new structure has been confirmed by total synthesis. Through the elaboration of structurally modified bleomycin congeners and fragments, synthetic efforts have also facilitated an understanding of the contribution of individual structural domains in bleomycin to sequence selective DNA binding and cleavage, and have also provided insights into the nature of the chemical processes by which DNA degradation takes place. Within the last several years, it has also become apparent that bleomycin can mediate the oxidative degradation of all major classes of cellular RNAs; it seems entirely plausible that RNA may also represent an important locus of action for this class of antitumor agent. In parallel with ongoing synthetic and mechanistic efforts using classical methods, the study of bleomycins attached to solid supports has been shown to provide important mechanistic insights, and the actual elaboration of modified bleomycins by solid phase synthesis constitutes a logical extension of such efforts.
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Affiliation(s)
- S M Hecht
- Departments of Chemistry and Biology, University of Virginia, Charlottesville, Virginia 22901, USA.
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