1
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Portugal J. Mithramycin and its analogs: Molecular features and antitumor action. Pharmacol Ther 2024; 260:108672. [PMID: 38838821 DOI: 10.1016/j.pharmthera.2024.108672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/09/2024] [Accepted: 06/01/2024] [Indexed: 06/07/2024]
Abstract
The antitumor antibiotic mithramycin A (MTA) binds to G/C-rich DNA sequences in the presence of dications. MTA inhibits transcription regulated by the Sp1 transcription factor, often enhanced during tumor development. It shows antitumor activity, but its clinical use was discontinued due to toxic side effects. However, recent observations have led to its use being reconsidered. The MTA biosynthetic pathways have been modified to produce mithramycin analogs (mithralogs) that encompass lower toxicity and improved pharmacological activity. Some mithralogs reduce gene expression in human ovarian and prostate tumors, among other types of cancer. They down-regulate gene expression in various cellular processes, including Sp1-responsive genes that control tumor development. Moreover, MTA and several mithralogs, such as EC-8042 (DIG-MSK) and EC-8105, effectively treat Ewing sarcoma by inhibiting transcription controlled by the oncogenic EWS-FLI1 transcription factor.
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Affiliation(s)
- José Portugal
- Instituto de Diagnóstico Ambiental y Estudios del Agua, CSIC, E-08034 Barcelona, Spain.
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2
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Bhosale SS, Mandal A, Hou C, McCorkle JR, Schweer D, Hill KS, Subramanian V, Kolesar JM, Tsodikov OV, Rohr J. Mithplatins: Mithramycin SA-Pt(II) Complex Conjugates for the Treatment of Platinum-Resistant Ovarian Cancers. ChemMedChem 2023; 18:e202200368. [PMID: 36342449 PMCID: PMC9899322 DOI: 10.1002/cmdc.202200368] [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: 07/08/2022] [Revised: 11/04/2022] [Indexed: 11/09/2022]
Abstract
DNA coordinating platinum (Pt) containing compounds cisplatin and carboplatin have been used for the treatment of ovarian cancer therapy for four decades. However, recurrent Pt-resistant cancers are a major cause of mortality. To combat Pt-resistant ovarian cancers, we designed and synthesized a conjugate of an anticancer drug mithramycin with a reactive Pt(II) bearing moiety, which we termed mithplatin. The conjugates displayed both the Mg2+ -dependent noncovalent DNA binding characteristic of mithramycin and the covalent crosslinking to DNA of the Pt. The conjugate was three times as potent as cisplatin against ovarian cancer cells. The DNA lesions caused by the conjugate led to the generation of DNA double-strand breaks, as also observed with cisplatin. Nevertheless, the conjugate was highly active against both Pt-sensitive and Pt-resistant ovarian cancer cells. This study paves the way to developing mithplatins to combat Pt-resistant ovarian cancers.
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Affiliation(s)
- Suhas S Bhosale
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY, 40536, USA
| | - Abhisek Mandal
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY, 40536, USA
| | - Caixia Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY, 40536, USA
| | - J Robert McCorkle
- Markey Cancer Center, University of Kentucky, 760 S. Rose Street, Lexington, KY, 40536, USA
| | - David Schweer
- Division of Gynecologic Oncology, College of Medicine, 760 S. Rose Street, Lexington, KY, 40536, USA
| | - Kristen S Hill
- Markey Cancer Center, University of Kentucky, 760 S. Rose Street, Lexington, KY, 40536, USA
| | - Vivekanandan Subramanian
- University of Kentucky PharmNMR Center, College of Pharmacy, University of Kentucky, Lexington, KY, 40536-0596, USA
| | - Jill M Kolesar
- Markey Cancer Center, University of Kentucky, 760 S. Rose Street, Lexington, KY, 40536, USA
- Division of Gynecologic Oncology, College of Medicine, 760 S. Rose Street, Lexington, KY, 40536, USA
- Department of Pharmacy Practice and Science, College of Pharmacy, University of Kentucky, 760 Press Avenue, Lexington, KY, 40536, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY, 40536, USA
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY, 40536, USA
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3
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Wu L, Zhang Q, Deng Z, Yu Y. From solo to duet, intersections of natural product assembly with self-resistance. Nat Prod Rep 2022; 39:919-925. [PMID: 34989738 DOI: 10.1039/d1np00064k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Covering: up to 2021Self-resistance mechanisms adopted by natural product producers have long been recognized and studied as a standalone system separated from the assembly machinery. However, as more examples of self-resistance have been characterized in detail, it has been revealed that self-resistance could associate with the assembly machinery to fulfill the task of biosynthesis. This review summarizes different self-resistance mechanisms showing a common feature: intersection with natural product assembly. Furthermore, their possible evolutionary origin and synthetic biology applications are discussed.
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Affiliation(s)
- Linrui Wu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China.
| | - Qian Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China.
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China.
| | - Yi Yu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China.
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Self-assembled DNA nanotrains for targeted delivery of mithramycin dimers coordinated by different metal ions: Effect of binding affinity on drug loading, release and cytotoxicity. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116722] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Schweer D, McCorkle JR, Rohr J, Tsodikov OV, Ueland F, Kolesar J. Mithramycin and Analogs for Overcoming Cisplatin Resistance in Ovarian Cancer. Biomedicines 2021; 9:biomedicines9010070. [PMID: 33445667 PMCID: PMC7828137 DOI: 10.3390/biomedicines9010070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Ovarian cancer is a highly deadly malignancy in which recurrence is considered incurable. Resistance to platinum-based chemotherapy bodes a particularly abysmal prognosis, underscoring the need for novel therapeutic agents and strategies. The use of mithramycin, an antineoplastic antibiotic, has been previously limited by its narrow therapeutic window. Recent advances in semisynthetic methods have led to mithramycin analogs with improved pharmacological profiles. Mithramycin inhibits the activity of the transcription factor Sp1, which is closely linked with ovarian tumorigenesis and platinum-resistance. This article summarizes recent clinical developments related to mithramycin and postulates a role for the use of mithramycin, or its analog, in the treatment of platinum-resistant ovarian cancer.
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Affiliation(s)
- David Schweer
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology Lexington, University of Kentucky Markey Cancer Center, Lexington, KY 40536, USA; (D.S.); (F.U.)
| | - J. Robert McCorkle
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA; (J.R.M.); (J.R.); (O.V.T.)
| | - Jurgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA; (J.R.M.); (J.R.); (O.V.T.)
| | - Oleg V. Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA; (J.R.M.); (J.R.); (O.V.T.)
| | - Frederick Ueland
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology Lexington, University of Kentucky Markey Cancer Center, Lexington, KY 40536, USA; (D.S.); (F.U.)
| | - Jill Kolesar
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology Lexington, University of Kentucky Markey Cancer Center, Lexington, KY 40536, USA; (D.S.); (F.U.)
- Correspondence:
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6
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Mithramycin A Radiosensitizes EWS:Fli1 + Ewing Sarcoma Cells by Inhibiting Double Strand Break Repair. Int J Radiat Oncol Biol Phys 2020; 109:1454-1471. [PMID: 33373655 DOI: 10.1016/j.ijrobp.2020.12.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 11/17/2020] [Accepted: 12/08/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE The oncogenic EWS:Fli1 fusion protein is a key transcriptional mediator of Ewing sarcoma initiation, progression, and therapeutic resistance. Mithramycin A (MithA) is a potent and specific inhibitor of transcription mediated by the EWS:Fli1. We tested the hypothesis that pretreatment with MithA could selectively radiosensitize EWS:Fli1+ tumor cells by altering the transcriptional response to radiation injury. METHODS AND MATERIALS A panel of 4 EWS:Fli1+ and 3 EWS:Fli1- Ewing sarcoma cell lines and 1 nontumor cell line were subjected to MithA dose-response viability assays to determine the relative potency of MithA in cells possessing or lacking the EWS:Fli1 fusion. Radiosensitization by MithA was evaluated by clonogenic survival assays in vitro and in a murine xenograft model. DNA damage was evaluated by comet assay and γ-H2Ax flow cytometry. Immunoblotting, flow cytometry, and reverse-transcription, polymerase chain reaction were used to evaluate DNA damage-induced signaling and repair processes and apoptosis. RESULTS We found that MithA alone could potently and selectively inhibit the growth of EWS:Fli1+ tumor cells, but not cells lacking this fusion. Pretreatment with MithA for 24 hours before irradiation significantly reduced clonogenic survival in vitro and delayed tumor regrowth in vivo, prolonging survival of EWS:Fli1+ tumor-bearing mice. Although MithA did not increase the level of DNA double-strand breaks, mechanistic studies revealed that MithA pretreatment selectively inhibited DNA double-strand break repair through downregulation of EWS:Fli1-mediated transcription, leading to tumor cell death by apoptosis. CONCLUSIONS Our data indicate that MithA is an effective radiosensitizer of EWS:Fli1+ tumors and may achieve better local control at lower doses of radiation.
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Hou C, Mandal A, Rohr J, Tsodikov OV. Allosteric interference in oncogenic FLI1 and ERG transactions by mithramycins. Structure 2020; 29:404-412.e4. [PMID: 33275876 DOI: 10.1016/j.str.2020.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/24/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022]
Abstract
ETS family transcription factors of ERG and FLI1 play a key role in oncogenesis of prostate cancer and Ewing sarcoma by binding regulatory DNA sites and interfering with function of other factors. Mithramycin (MTM) is an anti-cancer, DNA binding natural product that functions as a potent antagonist of ERG and FLI1 by an unknown mechanism. We present a series of crystal structures of the DNA binding domain (DBD) of ERG/FLI1 culminating in a structure of a high-order complex of the ERG/FLI1 DBD, transcription factor Runx2, core-binding factor beta (Cbfβ), and MTM on a DNA enhancer site, along with supporting DNA binding studies using MTM and its analogues. Taken together, these data provide insight into allosteric mechanisms underlying ERG and FLI1 transactions and their disruption by MTM analogues.
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Affiliation(s)
- Caixia Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Abhisek Mandal
- 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
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
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8
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Kormanec J, Novakova R, Csolleiova D, Feckova L, Rezuchova B, Sevcikova B, Homerova D. The antitumor antibiotic mithramycin: new advanced approaches in modification and production. Appl Microbiol Biotechnol 2020; 104:7701-7721. [DOI: 10.1007/s00253-020-10782-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022]
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9
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Wheeler R, Yu X, Hou C, Mitra P, Chen JM, Herkules F, Ivanov DN, Tsodikov OV, Rohr J. Discovery of a Cryptic Intermediate in Late Steps of Mithramycin Biosynthesis. Angew Chem Int Ed Engl 2019; 59:826-832. [PMID: 31702856 DOI: 10.1002/anie.201910241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/14/2019] [Indexed: 12/23/2022]
Abstract
MtmOIV and MtmW catalyze the final two reactions in the mithramycin (MTM) biosynthetic pathway, the Baeyer-Villiger opening of the fourth ring of premithramycin B (PMB), creating the C3 pentyl side chain, strictly followed by reduction of the distal keto group on the new side chain. Unexpectedly this results in a C2 stereoisomer of mithramycin, iso-mithramycin (iso-MTM). Iso-MTM undergoes a non-enzymatic isomerization to MTM catalyzed by Mg2+ ions. Crystal structures of MtmW and its complexes with co-substrate NADPH and PEG, suggest a catalytic mechanism of MtmW. The structures also show that a tetrameric assembly of this enzyme strikingly resembles the ring-shaped β subunit of a vertebrate ion channel. We show that MtmW and MtmOIV form a complex in the presence of PMB and NADPH, presumably to hand over the unstable MtmOIV product to MtmW, yielding iso-MTM, as a potential self-resistance mechanism against MTM toxicity.
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Affiliation(s)
- Ryan Wheeler
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Xia Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA.,Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, 410013, P. R. China
| | - Caixia Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Prithiba Mitra
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Jhong-Min Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Frank Herkules
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Dmitri N Ivanov
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
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10
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Wheeler R, Yu X, Hou C, Mitra P, Chen J, Herkules F, Ivanov DN, Tsodikov OV, Rohr J. Discovery of a Cryptic Intermediate in Late Steps of Mithramycin Biosynthesis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ryan Wheeler
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
| | - Xia Yu
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
- Xiangya School of Pharmaceutical SciencesCentral South University Changsha Hunan 410013 P. R. China
| | - Caixia Hou
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
| | - Prithiba Mitra
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
| | - Jhong‐Min Chen
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
| | - Frank Herkules
- Department of BiochemistryUniversity of Texas Health Science Center San Antonio TX 78229 USA
| | - Dmitri N. Ivanov
- Department of BiochemistryUniversity of Texas Health Science Center San Antonio TX 78229 USA
| | - Oleg V. Tsodikov
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
| | - Jürgen Rohr
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Kentucky 789 South Limestone Street Lexington KY 40536-0596 USA
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11
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Eckenrode JM, Mitra P, Rohr J, Leggas M. Bioanalytical method for quantitative determination of mithramycin analogs in mouse plasma by HPLC-QTOF. Biomed Chromatogr 2019; 33:e4544. [PMID: 30927450 DOI: 10.1002/bmc.4544] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 03/19/2019] [Accepted: 03/26/2019] [Indexed: 11/06/2022]
Abstract
Mithramycin (MTM) has potent anticancer activity, but severe toxicities restrict its clinical use. Semi-synthetic approaches have yielded novel MTM analogs with potentially lower toxicity and similar efficacy. In an effort to transition these analogs into in vivo models, a bioanalytical method was developed for their quantification in mouse plasma. Here we present the validation of the method for the quantitation of mithramycin SA-tryptophan (MTMSA-Trp) as well as the applicability of the methodology for assaying additional analogs, including MTM, mithramycin SK (MTMSK) and mithramycin SA-phenylalanine (MTMSA-Phe) with run times of 6 min. Assay linearity ranged from 5 to 100 ng/mL. Accuracies of calibration standards and quality control samples were within 15% of nominal with precision variability of <20%. MTMSA-Trp was stable for 30 days at -80°C and for at least three freeze-thaw cycles. Methanol (-80°C) extraction afforded 92% of MTMSA-Trp from plasma. Calibration curves for MTM and analogs were also linear from ≤5 to 100 ng/mL. This versatile method was used to quantitate MTM analogs in plasma samples collected during preclinical pharmacokinetic studies.
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Affiliation(s)
- Joseph M Eckenrode
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Prithiba Mitra
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Markos Leggas
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA
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12
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Hou C, Rohr J, Parkin S, Tsodikov OV. How mithramycin stereochemistry dictates its structure and DNA binding function. MEDCHEMCOMM 2019; 10:735-741. [PMID: 31191864 DOI: 10.1039/c9md00100j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/28/2019] [Indexed: 12/16/2022]
Abstract
An aureolic acid natural product mithramycin (MTM) has been known for its potent antineoplastic properties. MTM inhibits cell growth by binding in the minor groove of double-stranded DNA as a dimer, in which the two molecules of MTM are coordinated to each other through a divalent metal ion. A crystal structure of an MTM analogue, MTM SA-Phe, in the active metal ion-coordinated dimeric form demonstrates how the stereochemical features of MTM define the helicity of the dimeric scaffold for its binding to a right-handed DNA double helix. We also show crystallographically and biochemically that MTM, but not MTM SA-Phe, can be inactivated by boric acid through formation of a large macrocyclic species, in which two molecules of MTM are crosslinked to each other through 3-side chain-boron-sugar intermolecular bonds. We discuss these structural and biochemical properties in the context of MTM biosynthesis and the design of MTM analogues as anticancer therapeutics.
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Affiliation(s)
- Caixia Hou
- University of Kentucky , Department of Pharmaceutical Sciences , College of Pharmacy , Lexington , KY 40536-0596 , USA . ;
| | - Jürgen Rohr
- University of Kentucky , Department of Pharmaceutical Sciences , College of Pharmacy , Lexington , KY 40536-0596 , USA . ;
| | - Sean Parkin
- University of Kentucky , Department of Chemistry , Lexington , KY 40506-0055 , USA .
| | - Oleg V Tsodikov
- University of Kentucky , Department of Pharmaceutical Sciences , College of Pharmacy , Lexington , KY 40536-0596 , USA . ;
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13
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Hou C, Tsodikov OV. Utilizing guanine-coordinated Zn 2+ ions to determine DNA crystal structures by single-wavelength anomalous diffraction. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:32-40. [PMID: 30644843 DOI: 10.1107/s205979831801553x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/02/2018] [Indexed: 11/10/2022]
Abstract
The experimental phase determination of crystal structures of nucleic acids and nucleic acid-ligand complexes would benefit from a facile method. Even for double-stranded DNA, software-generated models are generally insufficiently accurate to serve as molecular replacement search models, necessitating experimental phasing. Here, it is demonstrated that Zn2+ ions coordinated to the N7 atom of guanine bases generate sufficient anomalous signal for single-wavelength anomalous diffraction (SAD) phasing of DNA crystal structures. Using zinc SAD, three crystal structures of double-stranded DNA oligomers, 5'-AGGGATCCCT-3', 5'-GGGATCCC-3' and 5'-GAGGCCTC-3', were determined. By determining the crystal structure of one of these oligomers, GAGGCCTC, in the presence of Mg2+ instead of Zn2+, it was demonstrated that Zn2+ is not structurally perturbing. These structures allowed the analysis of structural changes in the DNA on the binding of analogues of the natural product mithramycin to two of these oligomers, AGGGATCCCT and GAGGCCTC. Zinc SAD may become a routine approach for determining the crystal structures of nucleic acids and their complexes with small molecules.
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Affiliation(s)
- Caixia Hou
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
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14
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Bhaduri S, Ranjan N, Arya DP. An overview of recent advances in duplex DNA recognition by small molecules. Beilstein J Org Chem 2018; 14:1051-1086. [PMID: 29977379 PMCID: PMC6009268 DOI: 10.3762/bjoc.14.93] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/06/2018] [Indexed: 12/13/2022] Open
Abstract
As the carrier of genetic information, the DNA double helix interacts with many natural ligands during the cell cycle, and is amenable to such intervention in diseases such as cancer biogenesis. Proteins bind DNA in a site-specific manner, not only distinguishing between the geometry of the major and minor grooves, but also by making close contacts with individual bases within the local helix architecture. Over the last four decades, much research has been reported on the development of small non-natural ligands as therapeutics to either block, or in some cases, mimic a DNA–protein interaction of interest. This review presents the latest findings in the pursuit of novel synthetic DNA binders. This article provides recent coverage of major strategies (such as groove recognition, intercalation and cross-linking) adopted in the duplex DNA recognition by small molecules, with an emphasis on major works of the past few years.
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Affiliation(s)
| | - Nihar Ranjan
- National Institute of Pharmaceutical Education and Research (NIPER), Raebareli 122003, India
| | - Dev P Arya
- NUBAD, LLC, 900B West Faris Rd., Greenville 29605, SC, USA.,Clemson University, Hunter Laboratory, Clemson 29634, SC, USA
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15
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Hou C, Weidenbach S, Cano KE, Wang Z, Mitra P, Ivanov DN, Rohr J, Tsodikov OV. Structures of mithramycin analogues bound to DNA and implications for targeting transcription factor FLI1. Nucleic Acids Res 2016; 44:8990-9004. [PMID: 27587584 PMCID: PMC5063001 DOI: 10.1093/nar/gkw761] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/20/2016] [Indexed: 12/25/2022] Open
Abstract
Transcription factors have been considered undruggable, but this paradigm has been recently challenged. DNA binding natural product mithramycin (MTM) is a potent antagonist of oncogenic transcription factor EWS–FLI1. Structural details of MTM recognition of DNA, including the FLI1 binding sequence GGA(A/T), are needed to understand how MTM interferes with EWS–FLI1. We report a crystal structure of an MTM analogue MTM SA–Trp bound to a DNA oligomer containing a site GGCC, and two structures of a novel analogue MTM SA–Phe in complex with DNA. MTM SA–Phe is bound to sites AGGG and GGGT on one DNA, and to AGGG and GGGA(T) (a FLI1 binding site) on the other, revealing how MTM recognizes different DNA sequences. Unexpectedly, at sub-micromolar concentrations MTMs stabilize FLI1–DNA complex on GGAA repeats, which are critical for the oncogenic function of EWS–FLI1. We also directly demonstrate by nuclear magnetic resonance formation of a ternary FLI1–DNA–MTM complex on a single GGAA FLI1/MTM binding site. These biochemical and structural data and a new FLI1–DNA structure suggest that MTM binds the minor groove and perturbs FLI1 bound nearby in the major groove. This ternary complex model may lead to development of novel MTM analogues that selectively target EWS–FLI1 or other oncogenic transcription factors, as anti-cancer therapeutics.
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Affiliation(s)
- Caixia Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Stevi Weidenbach
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Kristin E Cano
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Zhonghua Wang
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Prithiba Mitra
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Dmitri N Ivanov
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jürgen Rohr
- 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
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