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Yates MK, Seley-Radtke KL. The evolution of antiviral nucleoside analogues: A review for chemists and non-chemists. Part II: Complex modifications to the nucleoside scaffold. Antiviral Res 2019; 162:5-21. [PMID: 30529089 PMCID: PMC6349489 DOI: 10.1016/j.antiviral.2018.11.016] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/24/2018] [Accepted: 11/30/2018] [Indexed: 12/13/2022]
Abstract
This is the second of two invited articles reviewing the development of nucleoside analogue antiviral drugs, written for a target audience of virologists and other non-chemists, as well as chemists who may not be familiar with the field. As with the first paper, rather than providing a chronological account, we have chosen to examine particular examples of structural modifications made to nucleoside analogues that have proven fruitful as various antiviral, anticancer, and other therapeutics. The first review covered the more common, and in most cases, single modifications to the sugar and base moieties of the nucleoside scaffold. This paper focuses on more recent developments, especially nucleoside analogues that contain more than one modification to the nucleoside scaffold. We hope that these two articles will provide an informative historical perspective of some of the successfully designed analogues, as well as many candidate compounds that encountered obstacles.
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Affiliation(s)
- Mary K Yates
- Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, USA
| | - Katherine L Seley-Radtke
- Department of Chemistry & Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, USA.
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Liu X, Jiang Y, Nowak B, Qiang B, Cheng N, Chen Y, Plunkett W. Targeting BRCA1/2 deficient ovarian cancer with CNDAC-based drug combinations. Cancer Chemother Pharmacol 2018; 81:255-267. [PMID: 29189915 PMCID: PMC5777892 DOI: 10.1007/s00280-017-3483-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/15/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE The mechanism of action of CNDAC (2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofuranosyl-cytosine) is unique among deoxycytidine analogs because upon incorporation into DNA it causes a single strand break which is converted to a double strand break after DNA replication. This lesion requires homologous recombination (HR) for repair. CNDAC, as the parent nucleoside, DFP10917, and as an oral prodrug, sapacitabine, are undergoing clinical trials for hematological malignancies and solid tumors. The purpose of this study is to investigate the potential of CNDAC for the therapy of ovarian cancer (OC). METHODS Drug sensitivity was evaluated using a clonogenic survival assay. Drug combination effects were quantified by median effect analysis. RESULTS OC cells lacking function of the key HR genes, BRCA1 or BRCA2, were more sensitive to CNDAC than corresponding HR proficient cells. The sensitization was associated with greater levels of DNA damage in response to CNDAC at clinically achievable concentrations, manifested as chromosomal aberrations. Three classes of CNDAC-based drug combinations were investigated. First, the PARP1 inhibitors, rucaparib and talazoparib, were selectively synergistic with CNDAC in BRCA1/2 deficient OC cells (combination index < 1) at a relatively low concentration range. Second, cisplatin and oxaliplatin had additive combination effects with CNDAC (combination index ~ 1). Finally, paclitaxel and docetaxel achieved additive cell-killing effects with CNDAC at concentration ranges of the taxanes similar for both BRCA1/2 deficient and proficient OC cells. CONCLUSIONS This study provides mechanistic rationales for combining CNDAC with PARP inhibitors, platinum compounds and taxanes in ovarian cancer lacking BRCA1/2 function.
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Affiliation(s)
- Xiaojun Liu
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - Yingjun Jiang
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - Billie Nowak
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - Bethany Qiang
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - Nancy Cheng
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - Yuling Chen
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA
| | - William Plunkett
- Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, 1901 East Road, 77054, Houston, TX, USA.
- Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, 77030, Houston, TX, USA.
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Iizuka K, Zhang C, Eshima K, Jin C, Eshima K, Fukushima M. Analysis of the prolonged infusion of DFP-10917, a deoxycytidine analog, as a therapeutic strategy for the treatment of human tumor xenografts in vivo. Int J Oncol 2018; 52:851-860. [PMID: 29344636 DOI: 10.3892/ijo.2018.4246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 01/12/2018] [Indexed: 11/05/2022] Open
Abstract
2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofranocyl-cytosine (DFP-10917, CNDAC) is a 2'-deoxycytidine analog with antitumor activity against various tumor cells. However, a clinically available therapeutic regimen for this compound needs to be established and its functional mechanisms in relation to the dosing schedule need to be clarified. In this study, we evaluated the antitumor activity and toxicity of DFP-10917 by varying the dose and administration schedule in human solid tumor and leukemia xenografts in vivo. Compared to a 1-day infusion with a high-dose of DFP-10917 (30 mg/kg/day), a prolonged 14-day infusion with a low-dose (4.5 mg/kg/day) exerted superior tumor growth inhibitory effects without decreasing the body weights of mice in our human tumor xenograft model. In addition, we found that a 14-day infusion of low-dose DFP-10917 markedly prolonged the lifespan of nude mice bearing both acute leukemia and ovarian cancer cell-derived tumors. On the other hand, gemcitabine (GEM) and cytosine arabinoside (Ara-C), which are similar deoxycytidine analogs and are widely used clinically as standard regimens, exerted less potent antitumor effects than DFP-10917 on these tumors. To elucidate the possible functional mechanisms of the prolonged infusion of DFP-10197 compared with that of GEM or Ara-C, the rate of DNA damage in CCRF-CEM and HeLa cells treated with DFP-10917, Ara-C and GEM was detected using a comet assay. DFP-10917, at a range of 0.05 to 1 µM, induced a clear tailed-DNA pattern in both the CCRF-CEM and HeLa cells; Ara-C and GEM did not have any effect. It was thus suggested that a low concentration and long-term exposure to DFP-10917 aggressively introduced the fragmentation of DNA molecules, namely the so-called double-strand breaks in tumor cells, leading to potent cytotoxicity. Moreover, treatment with DFP-10917 at a low-dose with a long-term exposure specifically increased the population of cells in the G2/M phase, while GEM reduced this cell population, suggesting a unique function (G2/M arrest) of DFP-10917. On the whole, our findings indicate that the prolonged infusion of low-dose DFP-10917 mainly displays a novel functional mechanism as a DNA-damaging drug and may thus prove to be useful in the treatment of cancer patients who are resistant to other cytosine nucleosides, or in patients in which these other nucleosides have been shown to be ineffective.
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Affiliation(s)
- Kenzo Iizuka
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
| | - Chun Zhang
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
| | - Kokoro Eshima
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
| | - Cheng Jin
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
| | - Kiyoshi Eshima
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
| | - Masakazu Fukushima
- Division of Oncology Research and Development, Delta-Fly Pharma Inc., Kawauchi-cho, Tokushima 771-0116, Japan
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Bone Marrow and Peripheral Blood AML Cells Are Highly Sensitive to CNDAC, the Active Form of Sapacitabine. Adv Hematol 2012; 2012:727683. [PMID: 23049558 PMCID: PMC3461608 DOI: 10.1155/2012/727683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/04/2012] [Indexed: 11/17/2022] Open
Abstract
Achieving improvements in survival and reducing relapse remains a challenge in acute myelogenous leukemia (AML) patients. This study evaluated the in vitro efficacy of the active form of novel agent sapacitabine, CNDAC, compared to current chemotherapeutic drugs Ara-C and mitoxantrone using two AML cell lines, HL-60 (promyelocytic) and THP-1 (monocytic), as well as bone marrow (BM) and peripheral blood (PB) cells collected from AML patients. Cell lines were exposed to compound for 3-6 days and primary cells for 4 days. The viability of primary cells was additionally evaluated 3, 7, and 31 days after removal of tested compound to determine the durability of the response. Our studies indicate that CNDAC and mitoxantrone have a greater impact on viability than ara-C in primary AML cells and AML cell lines. CNDAC is more effective at reducing viability and inducing apoptosis than ara-C at equivalent concentrations in the THP-1 cell line, which is defined as displaying resistance to ara-C. As sapacitabine has shown in vivo activity at clinically achievable doses, future studies are warranted to assess the potential for combining it with ara-C and/or mitoxantrone, with an emphasis on cells and patients insensitive to ara-C treatment.
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Abstract
INTRODUCTION Sapacitabine is an orally bioavailable nucleoside analog prodrug that is in clinical trials for hematologic malignancies and solid tumors. The active metabolite of sapacitabine, CNDAC (2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofuranosylcytosine), exhibits the unique mechanism of action of causing single-strand breaks (SSBs) after incorporation into DNA, which are converted into double-strand breaks (DSBs) when cells enter a second S-phase. CNDAC-induced DSBs are predominantly repaired through homologous recombination (HR). Cells deficient in HR components are greatly sensitized to CNDAC. Therefore, sapacitabine could be specifically effective against tumors that are deficient in this repair pathway. AREAS COVERED This review summarizes results from supporting evidence for the mechanisms of action of sapacitabine, its preclinical activities and the current results of clinical trials in a variety of cancers. The novel action mechanism of sapacitabine is discussed, with a view to validate it as a chemotherapeutic drug targeting malignancies with defects in HR. EXPERT OPINION Knowledge of CNDAC mechanism identifies tumors that may be sensitized to sapacitabine, thus enabling a personalized treatment strategy. It also creates the opportunity to overcome resistance to current front-line therapies and identify synergistic interactions with known anticancer drugs. The results of such investigations may provide rationales for the design of sapacitabine-based clinical trials.
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Affiliation(s)
- Xiaojun Liu
- The University of Texas M.D. Anderson Cancer Center, Department of Experimental Therapeutics, Houston, TX, USA
| | - Hagop Kantarjian
- The University of Texas M.D. Anderson Cancer Center, Department of Leukemia, Houston, TX, USA
| | - William Plunkett
- The University of Texas M.D. Anderson Cancer Center, Department of Experimental Therapeutics, Houston, TX, USA
- The University of Texas M.D. Anderson Cancer Center, Department of Leukemia, Houston, TX, USA
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Homologous recombination as a resistance mechanism to replication-induced double-strand breaks caused by the antileukemia agent CNDAC. Blood 2010; 116:1737-46. [PMID: 20479284 DOI: 10.1182/blood-2009-05-220376] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The nucleoside analog 2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofuranosyl-cytosine (CNDAC), currently in clinical trials for hematologic malignancies, has a novel action mechanism of causing a single-strand break after its incorporation into DNA. Double-strand breaks (DSBs) are generated thereafter in vivo and, if not repaired, pose lethal impact on cell survival. This study sought to define the mechanisms by which CNDAC-induced DSBs are formed and repaired. We demonstrated that single-strand breaks induced by CNDAC incorporation into DNA were converted to DSBs when cells progressed into the subsequent S-phase. CNDAC-induced DSBs were products of replication, rather than a consequence of apoptosis. ATM, the activator of homologous recombination (HR), was essential for cell survival after CNDAC treatment in cell lines and in primary acute myeloid leukemia samples, as were the HR components, Rad51, Xrcc3, and Brca2. Furthermore, formation of sister chromatid exchanges, a hallmark of HR, increased significantly after CNDAC-treated cells had progressed into a second replication cycle. In contrast, neither the replication stress sensor ATR nor DNA-PK, the initiator of nonhomologous end-joining of DSB, was involved in repair of CNDAC-induced damage. Together, these results indicate that HR, but not nonhomologous end-joining, is the major repair or survival mechanism for DNA damage caused by CNDAC.
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Kantarjian H, Garcia-Manero G, O'Brien S, Faderl S, Ravandi F, Westwood R, Green SR, Chiao JH, Boone PA, Cortes J, Plunkett W. Phase I clinical and pharmacokinetic study of oral sapacitabine in patients with acute leukemia and myelodysplastic syndrome. J Clin Oncol 2010; 28:285-91. [PMID: 19933907 PMCID: PMC3340938 DOI: 10.1200/jco.2009.25.0209] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Sapacitabine is an oral deoxycytidine nucleoside analog with a unique mechanism of action that is different from cytarabine. PATIENTS AND METHODS To define the dose-limiting toxicities (DLT) and maximum-tolerated dose (MTD) of sapacitabine given orally twice daily for 7 days every 3 to 4 weeks, or twice daily for 3 days for 2 weeks (days 1 through 3 and days 8 through 10) every 3 to 4 weeks, in refractory-relapse acute leukemia and myelodysplastic syndrome (MDS). A total of 47 patients were treated in the phase I study that used a classical 3 + 3 design. Sapacitabine was escalated from 75 to 375 mg twice daily for 7 days (n = 35) and from 375 to 475 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. RESULTS The DLTs with both schedules were gastrointestinal. The MTDs were 375 mg twice daily for 7 days and 425 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. The recommended phase II single-agent dose schedules were 325 mg twice daily for 7 days and 425 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. Responses were observed in 13 patients (28%); four were complete responses, and nine were marrow complete responses. CONCLUSION Sapacitabine is a new, safely administered, oral deoxycytidine analog that has encouraging activity in leukemia and MDS. Phase II studies are ongoing.
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Affiliation(s)
- Hagop Kantarjian
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom.,Corresponding author: Hagop Kantarjian, MD, The University of Texas M. D. Anderson Cancer Center, Department of Leukemia, Unit 428, 1515 Holcombe Blvd, Houston, TX 77030; e-mail:
| | - Guillermo Garcia-Manero
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Susan O'Brien
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Stefan Faderl
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Farhad Ravandi
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Robert Westwood
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Simon R. Green
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Judy H. Chiao
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Patricia A. Boone
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - Jorge Cortes
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
| | - William Plunkett
- From the Departments of Leukemia and Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX; and Cyclacel, Dundee, United Kingdom
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Parker WB. Enzymology of purine and pyrimidine antimetabolites used in the treatment of cancer. Chem Rev 2009; 109:2880-93. [PMID: 19476376 DOI: 10.1021/cr900028p] [Citation(s) in RCA: 375] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- William B Parker
- Southern Research Institute, 2000 Ninth Avenue, South Birmingham, Alabama 35205, USA.
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Wang Y, Liu X, Matsuda A, Plunkett W. Repair of 2′-C-Cyano-2′-Deoxy-1-β-d-arabino-Pentofuranosylcytosine–Induced DNA Single-Strand Breaks by Transcription-Coupled Nucleotide Excision Repair. Cancer Res 2008; 68:3881-9. [DOI: 10.1158/0008-5472.can-07-6885] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ohtawa M, Ichikawa S, Teishikata Y, Fujimuro M, Yokosawa H, Matsuda A. 9-(2-C-Cyano-2-deoxy-beta-D-arabino-pentofuranosyl)guanine, a potential antitumor agent against B-lymphoma infected with Kaposi's sarcoma-associated herpesvirus. J Med Chem 2007; 50:2007-10. [PMID: 17402726 DOI: 10.1021/jm070032y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several 9-(2-C-cyano-2-deoxy-l-beta-d-arabino-pentofuranosyl)purine derivatives were tested against Kaposi's sarcoma-associated herpesvirus (KSHV)-infected primary effusion lymphoma (PEL) cells. The guanine derivative (3, CNDAG), as well as the 2-amino-6-substituted-purine derivatives 4, 5, and 6, exhibited cell growth inhibitory activity against KSHV-infected cells, but showed no cytotoxicity against KSHV-negative cells at >15 microM concentrations. Therefore, it was found that compounds 3, 4, 5, and 6 showed selective cytotoxicity against PEL cells infected with KSHV.
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Affiliation(s)
- Masaki Ohtawa
- Department of Medicinal Chemistry and Biological Chemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Kita-12, Nishi-6, Sapporo 060-0812, Japan
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Uga H, Kuramori C, Ohta A, Tsuboi Y, Tanaka H, Hatakeyama M, Yamaguchi Y, Takahashi T, Kizaki M, Handa H. A new mechanism of methotrexate action revealed by target screening with affinity beads. Mol Pharmacol 2006; 70:1832-9. [PMID: 16936229 DOI: 10.1124/mol.106.025866] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Methotrexate (MTX) is the anticancer and antirheumatoid drug that is believed to block nucleotide synthesis and cell cycle by inhibiting dihydrofolate reductase activity. We have developed novel affinity matrices, termed SG beads, that are easy to manipulate and are compatible with surface functionalization. Using the matrices, here we present evidence that deoxycytidine kinase (dCK), an enzyme that acts in the salvage pathway of nucleotide biosynthesis, is another target of MTX. MTX modulates dCK activity differentially depending on substrate concentrations. 1-beta-D-Arabinofuranosylcytosine (ara-C), a chemotherapy agent often used in combination with MTX, is a nucleoside analog whose incorporation into chromosome requires prior phosphorylation by dCK. We show that, remarkably, MTX enhances incorporation and cytotoxicity of ara-C through regulation of dCK activity in Burkitt's lymphoma cells. Thus, this study provides new insight into the mechanisms underlying MTX actions and demonstrates the usefulness of the SG beads.
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Liu X, Guo Y, Li Y, Jiang Y, Chubb S, Azuma A, Huang P, Matsuda A, Hittelman W, Plunkett W. Molecular Basis for G2Arrest Induced by 2′-C-Cyano-2′-Deoxy-1-β-d-Arabino-Pentofuranosylcytosine and Consequences of Checkpoint Abrogation. Cancer Res 2005; 65:6874-81. [PMID: 16061671 DOI: 10.1158/0008-5472.can-05-0288] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC) is a nucleoside analogue with a novel mechanism of action that is currently being evaluated in clinical trials. Incorporation of CNDAC triphosphate into DNA and extension during replication leads to single-strand breaks directly caused by beta-elimination. These breaks, or the lesions that arise from further processing, cause cells to arrest in G2. The purpose of this investigation was to define the molecular basis for G2 checkpoint activation and to delineate the sequelae of its abrogation. Cell lines derived from diverse human tissues underwent G2 arrest after CNDAC treatment, suggesting a common mechanism of response to the damage created. CNDAC-induced G2 arrest was instituted by activation of the Chk1-Cdc25C-Cdk1/cyclin B checkpoint pathway. Neither Chk2, p38, nor p53 was required for checkpoint activation. Inhibition of Chk1 kinase with 7-hydroxystaurosporine (UCN-01) abrogated the checkpoint pathway as indicated by dephosphorylation of checkpoint proteins and progression of cells through mitosis and into G1. Cell death was first evident in hematologic cell lines after G1 entry. As indicated by histone H2AX phosphorylation, DNA damage initiated by CNDAC incorporation was transformed into double-strand breaks when ML-1 cells arrested in G2. Some breaks were manifested as chromosomal aberrations when the G2 checkpoint of CNDAC-arrested cells was abrogated by UCN-01 but also in a minor population of cells that escaped to mitosis during treatment with CNDAC alone. These findings provide a mechanistic rationale for the design of new strategies, combining CNDAC with inhibitors of cell cycle checkpoint regulation in the therapy of hematologic malignancies.
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Affiliation(s)
- Xiaojun Liu
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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Chatgilialoglu C, Ferreri C, Gimisis T, Roberti M, Balzarini J, De Clercq E. Synthesis and biological evaluation of novel 1'-branched and spironucleoside analogues. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2005; 23:1565-81. [PMID: 15620096 DOI: 10.1081/ncn-200031391] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Novel anomeric spironucleosides and 1'-cyano-2',3'-didehydro-2',3'-dideoxyuridine, a structural analogue of known anti-HIV agents, were prepared by nucleophilic addition of organolithium reagents to 1'-cyano-2'-deoxy- and 1'-cyano-2'-deoxy-2'beta-bromo-uridine derivatives, respectively. The yield and distribution of products depended on the reaction conditions, which were studied in detail. Although none of the compounds exhibited antiviral activity, two compounds displayed cytostatic activity against both murine leukemia and human T-lymphocyte cells.
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Abstract
Nucleoside analogues which show antimetabolic activity in cells have been successfully used in the treatment of various tumors. Nucleosides such as 1-beta-D-arabinofuranosylcytosine (araC), 6-mercaptopurine, fludarabine and cladribine play an important role in the treatment of leukemias, while gemcitabine, 5-fluorouracil and its prodrugs are used extensively in the treatment of many types of solid tumors. All of these compounds are metabolized similarly to endogenous nucleosides and nucleotides. Active metabolites interfere with the de novo synthesis of nucleosides and nucleotides or inhibit the DNA chain elongation after being incorporated into the DNA strand as terminators. Furthermore, nucleoside antimetabolites incorporated into the DNA strand induce strand-breaks and finally cause apoptosis. Nucleoside antimetabolites target one or more specific enzyme(s). The mode of inhibitory action on the target enzyme is not always similar even among nucleoside antimetabolites which have the same nucleoside base, such as araC and gemcitabine. Although both nucleosides are phosphorylated by deoxycytidine kinase and are also good substrates of cytidine deaminase, only gemcitabine shows antitumor activity against solid tumors. This suggests that differences in the pharmacological activity of these nucleoside antimetabolites may reflect different modes of action on target molecules. The design, in vitro cytotoxicity, in vivo antitumor activity, metabolism and mechanism of action of sugar-modified cytosine nucleosides, such as (2'S)-2'-deoxy-2'-C-methylcytidine (SMDC), 1-(2-deoxy-2-methylene-beta-D-erythro-pentofuranosyl)cytosine (DMDC), 1-(2-C-cyano-2-deoxy-1-beta-D-arabino-pentofuranosyl)cytosine (CNDAC) and 1-(3-C-ethynyl-beta-D-ribo-pentofura-nosyl)cytosine (ECyd), developed by our groups, are discussed here.
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Affiliation(s)
- Akira Matsuda
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0812, Japan.
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