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Saikia BS, Borpatra PJ, Rahman I, Deb ML, Baruah PK. Visible-light-promoted sulfenylation of 6-aminouracils under catalyst-free conditions. NEW J CHEM 2022. [DOI: 10.1039/d2nj01941h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Visible-light-promoted reactions have proven to be a decent strategy for the synthesis of complex molecules.
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Affiliation(s)
- B. Shriya Saikia
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati-781014, Assam, India
| | - Paran J. Borpatra
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati-781014, Assam, India
| | - Iftakur Rahman
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati-781014, Assam, India
| | - Mohit L. Deb
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati-781014, Assam, India
| | - Pranjal K. Baruah
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati-781014, Assam, India
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Nowrouzi N, Abbasi M, Shahidzadeh ES, Amaleh F. C(sp 2)–H bond sulfenylation of aminouracils and enaminones from aryl halides. NEW J CHEM 2022. [DOI: 10.1039/d1nj05726j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct thioarylation of aminouracils and enaminones from aryl iodides and bromides using potassium cyanodithioformate as an odorless and stable source of sulfur.
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Affiliation(s)
- N. Nowrouzi
- Department of Chemistry, Faculty of Nano and Bio Science and Technology, Persian Gulf University, Bushehr, 75169, Iran
| | - M. Abbasi
- Department of Chemistry, Faculty of Nano and Bio Science and Technology, Persian Gulf University, Bushehr, 75169, Iran
| | - E. Shaikhi Shahidzadeh
- Department of Chemistry, Faculty of Nano and Bio Science and Technology, Persian Gulf University, Bushehr, 75169, Iran
| | - F. Amaleh
- Department of Chemistry, Faculty of Nano and Bio Science and Technology, Persian Gulf University, Bushehr, 75169, Iran
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Devi J, Saikia N, Choudhury G, Deka DC. Iodine catalyzed regioselective sulfenylation of aminouracils with sulfonyl hydrazides. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2020.152753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Garcia RAG, Saydoff JA, Bamat MK, von Borstel RW. Prompt treatment with uridine triacetate improves survival and reduces toxicity due to fluorouracil and capecitabine overdose or dihydropyrimidine dehydrogenase deficiency. Toxicol Appl Pharmacol 2018; 353:67-73. [PMID: 29908244 DOI: 10.1016/j.taap.2018.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/01/2018] [Accepted: 06/12/2018] [Indexed: 11/26/2022]
Abstract
Uridine triacetate has been shown to be an effective antidote against mortality and toxicity caused by either overdoses or exaggerated susceptibility to the widely used anticancer agents 5-fluorouracil (5-FU) and capecitabine. However, a direct assessment of efficacy based on when emergency treatment was initiated was not clinically feasible. In this study we used mouse models of 5-FU overdose and of dihydropyrimidine dehydrogenase (DPD) deficiency to compare the efficacy of uridine triacetate in reducing toxicity and mortality when treatment was initiated at time points from 4 to 144 h after administration of 5-FU. We found that uridine triacetate was effective both in the 5-FU overdose and DPD deficiency models. Starting treatment within 24 h was most effective at reducing toxicity and mortality in both models, while treatment starting more than 96 to 120 h after 5-FU was far less effective. Uridine triacetate also reduced mortality in the DPD deficiency model when mice were treated with the 5-FU prodrug capecitabine. The results of this study are supportive of clinical observations and practice, indicating that efficacy declined progressively with later and later treatment initiation. Prompt treatment with uridine triacetate, within 24 h, conferred the greatest protection against 5-FU overexposure.
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Affiliation(s)
- Rolando A G Garcia
- Discovery Research, Wellstat Therapeutics, Rockville, MD, United States.
| | - Joel A Saydoff
- Currently at the National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, United States
| | - Michael K Bamat
- Research and Development, Wellstat Therapeutics, Rockville, MD, United States
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Human uridine phosphorylase-1 inhibitors: a new approach to ameliorate 5-fluorouracil-induced intestinal mucositis. Invest New Drugs 2014; 32:1301-7. [PMID: 25052233 DOI: 10.1007/s10637-014-0135-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/11/2014] [Indexed: 12/21/2022]
Abstract
PURPOSE 5-fluorouracil (5-FU) has been broadly used to treat solid tumors for more than 50 years. One of the major side effects of fluoropyrimidines therapy is oral and intestinal mucositis. Human uridine phosphorylase (hUP) inhibitors have been suggested as modulators of 5-FU toxicity. Therefore, the present study aimed to test the ability of hUP blockers in preventing mucositis induced by 5-FU. METHODS We induced intestinal mucositis in Wistar rats with 5-FU, and the intestinal damage was evaluated in presence or absence of two hUP1 inhibitors previously characterized. We examined the loss of weight and diarrhea following the treatment, the villus integrity, uridine levels in plasma, and the neutrophil migration by MPO activity. RESULTS We found that one of the compounds, 6-hydroxy-4-methyl-1H-pyridin-2-one-3-carbonitrile was efficient to promote intestinal mucosa protection and to inhibit the hUP1 enzyme, increasing the uridine levels in the plasma of animals. However, the loss of body weight, diarrhea intensity or neutrophil migration remained unaffected. CONCLUSION Our results bring support to the hUP1 inhibitor strategy as a novel possibility of prevention and treatment of mucositis during the 5-FU chemotherapy, based on the approach of uridine accumulation in plasma and tissues.
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Renck D, Machado P, Souto AA, Rosado LA, Erig T, Campos MM, Farias CB, Roesler R, Timmers LFSM, de Souza ON, Santos DS, Basso LA. Design of novel potent inhibitors of human uridine phosphorylase-1: synthesis, inhibition studies, thermodynamics, and in vitro influence on 5-fluorouracil cytotoxicity. J Med Chem 2013; 56:8892-902. [PMID: 24131420 DOI: 10.1021/jm401389u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Uridine (Urd) is a promising biochemical modulator to reduce host toxicity caused by 5-fluorouracil (5-FU) without impairing its antitumor activity. Elevated doses of Urd are required to achieve a protective effect against 5-FU toxicity, but exogenous administration of Urd is not well-tolerated. Selective inhibitors of human uridine phosphorylase (hUP) have been proposed as a strategy to increase Urd levels. We describe synthesis and characterization of a new class of ligands that inhibit hUP type 1 (hUP1). The design of ligands was based on a possible SN1 catalytic mechanism and as mimics of the carbocation in the transition state of hUP1. The kinetic and thermodynamic profiles showed that the ligands here presented are the most potent in vitro hUP1 inhibitors developed to date. In addition, a lead compound improved the antiproliferative effects of 5-FU on colon cancer cells, accompanied by a reduction of in vitro 5-FU cytotoxicity in aggressive SW-620 cancer cells.
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Affiliation(s)
- Daiana Renck
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) , 6681/92-A, TecnoPuc, Av. Ipiranga, 90619-900 Porto Alegre, Rio Grande do Sul, Brazil
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Potent combination therapy for human breast tumors with high doses of 5-fluorouracil: remission and lack of host toxicity. Cancer Chemother Pharmacol 2012; 69:1449-55. [PMID: 22373605 DOI: 10.1007/s00280-012-1842-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/30/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE The purpose of this investigation was to evaluate the effectiveness of oral 5-(phenylthio)acyclouridine (PTAU) in reducing 5-fluorouracil (FUra) host toxicity and enhancing its chemotherapeutic efficacy against human breast tumors. PTAU is a potent and specific inhibitor of uridine phosphorylase (UP, EC 2.4.2.3), the enzyme responsible for uridine catabolism. METHODS SCID mice bearing MDA-MB-468 and MCF-7 human breast tumors were injected intraperitoneally with FUra (50, 200 or 300 mg/kg) on days 17, 24, and 31 after tumor cell inoculation. PTAU (120 mg/kg), uridine (1,320 mg/kg), or their combination was administered orally two or 4 h after FUra injection. Another four administrations of PTAU plus uridine were given every 8 h after the first treatment with PTAU plus uridine. Survival and body weight were used to evaluate host toxicity. Tumor weight was used to evaluate the efficacy of the drugs on tumor growth. The mice were monitored for 38 days. RESULTS Administration of the maximum tolerated dose (50 mg/kg) of 5-fluorouracil (FUra) to SCID mice bearing human breast MDA-MB-468 and MCF-7 adenocarcinoma tumor xenografts reduced tumor weight by 59 and 61%, respectively. Administration of 200 mg/kg FUra resulted in 100% mortality. Oral administration of uridine (1,320 mg/kg) alone, 2 h following the administration of 200 mg/kg FUra, did not rescue from FUra host toxicity as all the mice died. Administration of 120 mg/kg PTAU resulted in partial rescue from this lethal dose of FUra as 38% of inoculated mice survived and the tumor weights were reduced by approximately 67%. Coadministration of PTAU plus uridine resulted in complete rescue from the toxicity of FUra. All of the mice survived, and MDA-MB-468 and MCF-7 tumor weights were reduced by 97% and total remission, respectively. Doubling the FUra treatment dose to 400 mg/kg in the MDA-MB-468 inoculated mice, with the administration of the adjuvant combination treatment of PTAU plus uridine, was unsuccessful in rescuing from FUra toxicity as all the mice died. Lowering the dose of FUra to 300 mg/kg, under the same conditions, resulted in 67% mice survival, and the MCF-7 tumor weights were reduced by 100%. Treatment with uridine alone did not protect from FUra toxicity at 200, 300, and 400 mg/kg as all of the mice died. At the higher dose of 300 and 400 mg/kg FUra, PTAU alone had no rescuing effect. There was no significant difference between MDA-MB-468 and MCF-7 in their response to the different regimens employed in this study in spite of the fact that MDA-MB-468 is estrogen receptor negative while MCF-7 is estrogen receptor positive. CONCLUSIONS The present results demonstrate that the combination of PTAU plus uridine represents an exceptionally efficient method in increasing FUra chemotherapeutic efficacy while minimizing its host toxicity. The efficiency of the PTAU plus uridine combination can be attributed to the extraordinary effectiveness of this combination treatment in raising and maintaining higher levels of uridine in vivo (Al Safarjalani et al. in Cancer Chemo Pharmacol 55:541-551, 2005). Therefore, the combination of PTAU plus uridine can provide a better substitute for the massive doses of uridine necessary to rescue or protect from FUra host-toxicities, without the toxic side effects associated with such doses of uridine. The combination may also allow the escalation of FUra doses for better chemotherapeutic efficacy against human breast carcinoma, with the possibility of avoiding FUra host-toxicities. Alternatively, the combination of PTAU and uridine may be useful as an antidote in the few cases when cancer patients receive a lethal overdose of FUra.
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Inhibition of pyrimidine and purine nucleoside phosphorylases by a 3,5-dichlorobenzoyl-substituted 2-deoxy-D-ribose-1-phosphate derivative. Biochem Pharmacol 2012; 83:1358-63. [PMID: 22366108 DOI: 10.1016/j.bcp.2012.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 11/23/2022]
Abstract
The 3,5-dichlorobenzoyl-substituted 2-deoxy-D-ribose-1-phosphate derivative, designated Cf2891, was found to inhibit a variety of pyrimidine and purine nucleoside phosphorylases (NPs) with preference for uridine- and inosine-hydrolyzing enzymes [uridine phosphorylase (UP; EC 2.4.2.3), pyrimidine nucleoside phosphorylase (PyNP; EC 2.4.2.2) and purine nucleoside phosphorylase (PNP; EC 2.4.2.1)]. Kinetic analyses revealed that Cf2891 competes with inorganic phosphate (P(i)) for binding to the NPs and, depending on the nature of the enzyme, acts as a competitive or non-competitive inhibitor with regard to the nucleoside binding site. Also, the compound prevents breakdown of pyrimidine analogues used in the treatment of viral infections and cancer. Since NPs are abundantly present in tumor tissue and may be overexpressed due to secondary bacterial infections in immunocompromised patients suffering viral infections, Cf2891 may serve as a lead molecule for the development of inhibitors to be used in nucleoside-based combination therapy.
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Roosild TP, Castronovo S, Villoso A, Ziemba A, Pizzorno G. A novel structural mechanism for redox regulation of uridine phosphorylase 2 activity. J Struct Biol 2011; 176:229-37. [PMID: 21855639 DOI: 10.1016/j.jsb.2011.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 08/02/2011] [Accepted: 08/02/2011] [Indexed: 01/16/2023]
Abstract
Uridine phosphorylase (UPP) catalyzes the reversible conversion of uridine to uracil and ribose-1-phosphate and plays an important pharmacological role in activating fluoropyrimidine nucleoside chemotherapeutic agents such as 5-fluorouracil and capecitabine. Most vertebrate animals, including humans, possess two homologs of this enzyme (UPP1 & UPP2), of which UPP1 has been more thoroughly studied and is better characterized. Here, we report two crystallographic structures of human UPP2 (hUPP2) in distinctly active and inactive conformations. These structures reveal that a conditional intramolecular disulfide bridge can form within the protein that dislocates a critical phosphate-coordinating arginine residue (R100) away from the active site, disabling the enzyme. In vitro activity measurements on both recombinant hUPP2 and native mouse UPP2 confirm the redox sensitivity of this enzyme, in contrast to UPP1. Sequence analysis shows that this feature is conserved among UPP2 homologs and lacking in all UPP1 proteins due to the absence of a necessary cysteine residue. The state of the disulfide bridge has further structural consequences for one face of the enzyme that suggest UPP2 may have additional functions in sensing and initiating cellular responses to oxidative stress. The molecular details surrounding these dynamic aspects of hUPP2 structure and regulation provide new insights as to how novel inhibitors of this protein may be developed with improved specificity and affinity. As uridine is emerging as a promising protective compound in neuro-degenerative diseases, including Alzheimer's and Parkinson's, understanding the regulatory mechanisms underlying UPP control of uridine concentration is key to improving clinical outcomes in these illnesses.
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Affiliation(s)
- Tarmo P Roosild
- Department of Drug Development, Nevada Cancer Institute, One Breakthrough Way, Las Vegas, NV 89135, USA.
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Roosild TP, Castronovo S. Active site conformational dynamics in human uridine phosphorylase 1. PLoS One 2010; 5:e12741. [PMID: 20856879 PMCID: PMC2939078 DOI: 10.1371/journal.pone.0012741] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 08/20/2010] [Indexed: 11/18/2022] Open
Abstract
Uridine phosphorylase (UPP) is a central enzyme in the pyrimidine salvage pathway, catalyzing the reversible phosphorolysis of uridine to uracil and ribose-1-phosphate. Human UPP activity has been a focus of cancer research due to its role in activating fluoropyrimidine nucleoside chemotherapeutic agents such as 5-fluorouracil (5-FU) and capecitabine. Additionally, specific molecular inhibitors of this enzyme have been found to raise endogenous uridine concentrations, which can produce a cytoprotective effect on normal tissues exposed to these drugs. Here we report the structure of hUPP1 bound to 5-FU at 2.3 A resolution. Analysis of this structure reveals new insights as to the conformational motions the enzyme undergoes in the course of substrate binding and catalysis. The dimeric enzyme is capable of a large hinge motion between its two domains, facilitating ligand exchange and explaining observed cooperativity between the two active sites in binding phosphate-bearing substrates. Further, a loop toward the back end of the uracil binding pocket is shown to flexibly adjust to the varying chemistry of different compounds through an "induced-fit" association mechanism that was not observed in earlier hUPP1 structures. The details surrounding these dynamic aspects of hUPP1 structure and function provide unexplored avenues to develop novel inhibitors of this protein with improved specificity and increased affinity. Given the recent emergence of new roles for uridine as a neuron protective compound in ischemia and degenerative diseases, such as Alzheimer's and Parkinson's, inhibitors of hUPP1 with greater efficacy, which are able to boost cellular uridine levels without adverse side-effects, may have a wide range of therapeutic applications.
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Affiliation(s)
- Tarmo P Roosild
- Department of Drug Development, Nevada Cancer Institute, Las Vegas, Nevada, United States of America.
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Kim S, Park DH, Kim TH, Hwang M, Shim J. Functional analysis of pyrimidine biosynthesis enzymes using the anticancer drug 5-fluorouracil in Caenorhabditis elegans. FEBS J 2009; 276:4715-26. [PMID: 19645718 DOI: 10.1111/j.1742-4658.2009.07168.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pyrimidine biosynthesis enzymes function in many cellular processes and are closely associated with pyrimidine antagonists used in cancer chemotherapy. These enzymes are well characterized from bacteria to mammals, but not in a simple metazoan. To study the pyrimidine biosynthesis pathway in Caenorhabditis elegans, we screened for mutants exhibiting resistance to the anticancer drug 5-fluorouracil (5-FU). In several strains, mutations were identified in ZK783.2, the worm homolog of human uridine phosphorylase (UP). UP is a member of the pyrimidine biosynthesis family of enzymes and is a key regulator of uridine homeostasis. C. elegans UP homologous protein (UPP-1) exhibited both uridine and thymidine phosphorylase activity in vitro. Knockdown of other pyrimidine biosynthesis enzyme homologs, such as uridine monophosphate kinase and uridine monophosphate synthetase, also resulted in 5-FU resistance. Uridine monophosphate kinase and uridine monophosphate synthetase proteins are redundant, and show different, tissue-specific expression patterns in C. elegans. Whereas pyrimidine biosynthesis pathways are highly conserved between worms and humans, no human thymidine phosphorylase homolog has been identified in C. elegans. UPP-1 functions as a key regulator of the pyrimidine salvage pathway in C. elegans, as mutation of upp-1 results in strong 5-FU resistance.
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Affiliation(s)
- Seongseop Kim
- Cancer Experimental Resources Branch, National Cancer Center, Gyeonggi-do, Korea
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Cirillo G, Iemma F, Puoci F, Parisi OI, Curcio M, Spizzirri UG, Picci N. Imprinted hydrophilic nanospheres as drug delivery systems for 5-fluorouracil sustained release. J Drug Target 2009; 17:72-7. [PMID: 19016107 DOI: 10.1080/10611860802455813] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Molecularly imprinted hydrogel nanospheres as devices for the controlled/sustained release of 5-fluororacil in biological fluids were synthesized employing one-pot precipitation technique as the polymerization method. Methacrylic acid as a functional monomer and ethylene glycole dimethacrylate as a cross-linker were used in polymeric feed. Morphological and hydrophilic properties were determined by scanning electron microscopy and water content measurement, and recognition and selectivity properties of spherical molecularly imprinted polymers were compared with the spherical non-imprinted polymers, both in organic (acetonitrile) and water media. Finally, in vitro release studies were performed in plasma simulating fluids.
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Affiliation(s)
- G Cirillo
- Dipartimento di Scienze Farmaceutiche, Universita della Calabria, Edificio Polifunzionale, Arcavacata di Rende, Italy
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Roosild TP, Castronovo S, Fabbiani M, Pizzorno G. Implications of the structure of human uridine phosphorylase 1 on the development of novel inhibitors for improving the therapeutic window of fluoropyrimidine chemotherapy. BMC STRUCTURAL BIOLOGY 2009; 9:14. [PMID: 19291308 PMCID: PMC2664818 DOI: 10.1186/1472-6807-9-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 03/16/2009] [Indexed: 11/10/2022]
Abstract
Background Uridine phosphorylase (UPP) is a key enzyme of pyrimidine salvage pathways, catalyzing the reversible phosphorolysis of ribosides of uracil to nucleobases and ribose 1-phosphate. It is also a critical enzyme in the activation of pyrimidine-based chemotherapeutic compounds such a 5-fluorouracil (5-FU) and its prodrug capecitabine. Additionally, an elevated level of this enzyme in certain tumours is believed to contribute to the selectivity of such drugs. However, the clinical effectiveness of these fluoropyrimidine antimetabolites is hampered by their toxicity to normal tissue. In response to this limitation, specific inhibitors of UPP, such as 5-benzylacyclouridine (BAU), have been developed and investigated for their ability to modulate the cytotoxic side effects of 5-FU and its derivatives, so as to increase the therapeutic index of these agents. Results In this report we present the high resolution structures of human uridine phosphorylase 1 (hUPP1) in ligand-free and BAU-inhibited conformations. The structures confirm the unexpected solution observation that the human enzyme is dimeric in contrast to the hexameric assembly present in microbial UPPs. They also reveal in detail the mechanism by which BAU engages the active site of the protein and subsequently disables the enzyme by locking the protein in a closed conformation. The observed inter-domain motion of the dimeric human enzyme is much greater than that seen in previous UPP structures and may result from the simpler oligomeric organization. Conclusion The structural details underlying hUPP1's active site and additional surfaces beyond these catalytic residues, which coordinate binding of BAU and other acyclouridine analogues, suggest avenues for future design of more potent inhibitors of this enzyme. Notably, the loop forming the back wall of the substrate binding pocket is conformationally different and substantially less flexible in hUPP1 than in previously studied microbial homologues. These distinctions can be utilized to discover novel inhibitory compounds specifically optimized for efficacy against the human enzyme as a step toward the development of more effective chemotherapeutic regimens that can selectively protect normal tissues with inherently lower UPP activity.
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Affiliation(s)
- Tarmo P Roosild
- Department of Drug Development, Nevada Cancer Institute, Las Vegas, Nevada, USA.
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