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Nguyen TN, Ingle C, Thompson S, Reynolds KA. The genetic landscape of a metabolic interaction. Nat Commun 2024; 15:3351. [PMID: 38637543 PMCID: PMC11026382 DOI: 10.1038/s41467-024-47671-0] [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: 08/17/2023] [Accepted: 04/09/2024] [Indexed: 04/20/2024] Open
Abstract
While much prior work has explored the constraints on protein sequence and evolution induced by physical protein-protein interactions, the sequence-level constraints emerging from non-binding functional interactions in metabolism remain unclear. To quantify how variation in the activity of one enzyme constrains the biochemical parameters and sequence of another, we focus on dihydrofolate reductase (DHFR) and thymidylate synthase (TYMS), a pair of enzymes catalyzing consecutive reactions in folate metabolism. We use deep mutational scanning to quantify the growth rate effect of 2696 DHFR single mutations in 3 TYMS backgrounds under conditions selected to emphasize biochemical epistasis. Our data are well-described by a relatively simple enzyme velocity to growth rate model that quantifies how metabolic context tunes enzyme mutational tolerance. Together our results reveal the structural distribution of epistasis in a metabolic enzyme and establish a foundation for the design of multi-enzyme systems.
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Affiliation(s)
- Thuy N Nguyen
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- The Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- The Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Form Bio, Dallas, TX, 75226, USA
| | - Christine Ingle
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- The Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- The Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Samuel Thompson
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, 94158, USA
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Kimberly A Reynolds
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- The Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- The Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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2
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Nguyen TN, Ingle C, Thompson S, Reynolds KA. The Genetic Landscape of a Metabolic Interaction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.28.542639. [PMID: 37645784 PMCID: PMC10461916 DOI: 10.1101/2023.05.28.542639] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Enzyme abundance, catalytic activity, and ultimately sequence are all shaped by the need of growing cells to maintain metabolic flux while minimizing accumulation of deleterious intermediates. While much prior work has explored the constraints on protein sequence and evolution induced by physical protein-protein interactions, the sequence-level constraints emerging from non-binding functional interactions in metabolism remain unclear. To quantify how variation in the activity of one enzyme constrains the biochemical parameters and sequence of another, we focused on dihydrofolate reductase (DHFR) and thymidylate synthase (TYMS), a pair of enzymes catalyzing consecutive reactions in folate metabolism. We used deep mutational scanning to quantify the growth rate effect of 2,696 DHFR single mutations in 3 TYMS backgrounds under conditions selected to emphasize biochemical epistasis. Our data are well-described by a relatively simple enzyme velocity to growth rate model that quantifies how metabolic context tunes enzyme mutational tolerance. Together our results reveal the structural distribution of epistasis in a metabolic enzyme and establish a foundation for the design of multi-enzyme systems.
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Affiliation(s)
- Thuy N. Nguyen
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
| | - Christine Ingle
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
| | - Samuel Thompson
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158
| | - Kimberly A. Reynolds
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, USA, 75390
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3
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Pozzi C, Lopresti L, Tassone G, Mangani S. Targeting Methyltransferases in Human Pathogenic Bacteria: Insights into Thymidylate Synthase (TS) and Flavin-Dependent TS (FDTS). Molecules 2019; 24:molecules24081638. [PMID: 31027295 PMCID: PMC6514825 DOI: 10.3390/molecules24081638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/18/2019] [Accepted: 04/25/2019] [Indexed: 01/10/2023] Open
Abstract
In cells, thymidylate synthases provide the only de novo source of 2′-deoxythymidine-5′-monophosphate (dTMP), required for DNA synthesis. The activity of these enzymes is pivotal for cell survival and proliferation. Two main families of thymidylate synthases have been identified in bacteria, folate-dependent thymidylate synthase (TS) and flavin-dependent TS (FDTS). TS and FDTS are highly divergent enzymes, characterized by exclusive catalytic mechanisms, involving different sets of cofactors. TS and FDTS mechanisms of action have been recently revised, providing new perspectives for the development of antibacterial drugs targeting these enzymes. Nonetheless, some catalytic details still remain elusive. For bacterial TSs, half-site reactivity is still an open debate and the recent evidences are somehow controversial. Furthermore, different behaviors have been identified among bacterial TSs, compromising the definition of common mechanisms. Moreover, the redox reaction responsible for the regeneration of reduced flavin in FDTSs is not completely clarified. This review describes the recent advances in the structural and functional characterization of bacterial TSs and FDTSs and the current understanding of their mechanisms of action. Furthermore, the recent progresses in the development of inhibitors targeting TS and FDTS in human pathogenic bacteria are summarized.
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Affiliation(s)
- Cecilia Pozzi
- Department of Biotechnology, Chemistry and Pharmacy⁻Department of Excellence 2018-2020, University of Siena, via Aldo Moro 2, 53100 Siena, Italy.
| | - Ludovica Lopresti
- Department of Biotechnology, Chemistry and Pharmacy⁻Department of Excellence 2018-2020, University of Siena, via Aldo Moro 2, 53100 Siena, Italy.
| | - Giusy Tassone
- Department of Biotechnology, Chemistry and Pharmacy⁻Department of Excellence 2018-2020, University of Siena, via Aldo Moro 2, 53100 Siena, Italy.
| | - Stefano Mangani
- Department of Biotechnology, Chemistry and Pharmacy⁻Department of Excellence 2018-2020, University of Siena, via Aldo Moro 2, 53100 Siena, Italy.
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4
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Sharaf A, Oborník M, Hammad A, El-Afifi S, Marei E. Characterization and comparative genomic analysis of virulent and temperate Bacillus megaterium bacteriophages. PeerJ 2018; 6:e5687. [PMID: 30581654 PMCID: PMC6292376 DOI: 10.7717/peerj.5687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/03/2018] [Indexed: 11/20/2022] Open
Abstract
Next-Generation Sequencing (NGS) technologies provide unique possibilities for the comprehensive assessment of the environmental diversity of bacteriophages. Several Bacillus bacteriophages have been isolated, but very few Bacillus megaterium bacteriophages have been characterized. In this study, we describe the biological characteristics, whole genome sequences, and annotations for two new isolates of the B. megaterium bacteriophages (BM5 and BM10), which were isolated from Egyptian soil samples. Growth analyses indicated that the phages BM5 and BM10 have a shorter latent period (25 and 30 min, respectively) and a smaller burst size (103 and 117 PFU, respectively), in comparison to what is typical for Bacillus phages. The genome sizes of the phages BM5 and BM10 were 165,031 bp and 165,213 bp, respectively, with modular organization. Bioinformatic analyses of these genomes enabled the assignment of putative functions to 97 and 65 putative ORFs, respectively. Comparative analysis of the BM5 and BM10 genome structures, in conjunction with other B. megaterium bacteriophages, revealed relatively high levels of sequence and organizational identity. Both genomic comparisons and phylogenetic analyses support the conclusion that the sequenced phages (BM5 and BM10) belong to different sub-clusters (L5 and L7, respectively), within the L-cluster, and display different lifestyles (lysogenic and lytic, respectively). Moreover, sequenced phages encode proteins associated with Bacillus pathogenesis. In addition, BM5 does not contain any tRNA sequences, whereas BM10 genome codes for 17 tRNAs.
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Affiliation(s)
- Abdoallah Sharaf
- Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Adel Hammad
- Department of Microbiology, Faculty of Agriculture, Minia University, Minia, Egypt
| | - Sohair El-Afifi
- Department of Agricultural Microbiology, Virology Laboratory, Ain Shams University, Cairo, Egypt
| | - Eman Marei
- Department of Agricultural Microbiology, Virology Laboratory, Ain Shams University, Cairo, Egypt
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Lopez-Zavala AA, Guevara-Hernandez E, Vazquez-Lujan LH, Sanchez-Paz A, Garcia-Orozco KD, Contreras-Vergara CA, Lopez-Leal G, Arvizu-Flores AA, Ochoa-Leyva A, Sotelo-Mundo RR. A novel thymidylate synthase from the Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) clade with altered nucleotide and folate binding sites. PeerJ 2018; 6:e5023. [PMID: 29922516 PMCID: PMC6005164 DOI: 10.7717/peerj.5023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/23/2018] [Indexed: 12/21/2022] Open
Abstract
Thymidylate synthase (TS, E.C. 2.1.1.45) is a crucial enzyme for de novo deoxythymidine monophosphate (dTMP) biosynthesis. The gene for this enzyme is thyA, which encodes the folate-dependent TS that converts deoxyuridine monophosphate group (dUMP) into (dTMP) using the cofactor 5,10-methylenetetrahydrofolate (mTHF) as a carbon donor. We identified the thyA gene in the genome of the Vibrio parahaemolyticus strain FIM-S1708+ that is innocuous to humans but pathogenic to crustaceans. Surprisingly, we found changes in the residues that bind the substrate dUMP and mTHF, previously postulated as invariant among all TSs known (Finer-Moore, Santi & Stroud, 2003). Interestingly, those amino acid changes were also found in a clade of microorganisms that contains Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) from the Gammaproteobacteria class. In this work, we studied the biochemical properties of recombinant TS from V. parahemolyticus FIM-S1708+ (VpTS) to address the natural changes in the TS amino acid sequence of the VAAP clade. Interestingly, the Km for dUMP was 27.3 ± 4.3 µM, about one-fold larger compared to other TSs. The Km for mTHF was 96.3 ± 18 µM, about three- to five-fold larger compared to other species, suggesting also loss of affinity. Thus, the catalytic efficiency was between one or two orders of magnitude smaller for both substrates. We used trimethoprim, a common antibiotic that targets both TS and DHFR for inhibition studies. The IC50 values obtained were high compared to other results in the literature. Nonetheless, this molecule could be a lead for the design antibiotics towards pathogens from the VAAP clade. Overall, the experimental results also suggest that in the VAAP clade the nucleotide salvage pathway is important and should be investigated, since the de novo dTMP synthesis appears to be compromised by a less efficient thymidylate synthase.
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Affiliation(s)
- Alonso A Lopez-Zavala
- Biomolecular Structure Laboratory, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico.,Departamento de Ciencias Quimico Biologicas, Universidad de Sonora, Hermosillo, Sonora, Mexico
| | - Eduardo Guevara-Hernandez
- Biomolecular Structure Laboratory, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico
| | - Luz H Vazquez-Lujan
- Biomolecular Structure Laboratory, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico
| | - Arturo Sanchez-Paz
- Laboratorio de Referencia, Análisis y Diagnóstico en Sanidad Acuícola, Centro de Investigaciones Biologicas del Noroeste, Hermosillo, Sonora, Mexico
| | - Karina D Garcia-Orozco
- Biomolecular Structure Laboratory, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico
| | - Carmen A Contreras-Vergara
- Laboratorio de Genetica de Plantas, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico
| | - Gamaliel Lopez-Leal
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Aldo A Arvizu-Flores
- Departamento de Ciencias Quimico Biologicas, Universidad de Sonora, Hermosillo, Sonora, Mexico
| | - Adrian Ochoa-Leyva
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Rogerio R Sotelo-Mundo
- Biomolecular Structure Laboratory, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora, Mexico
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Ghosh AK, Islam Z, Krueger J, Abeysinghe T, Kohen A. The general base in the thymidylate synthase catalyzed proton abstraction. Phys Chem Chem Phys 2015; 17:30867-75. [PMID: 25912171 PMCID: PMC4624062 DOI: 10.1039/c5cp01246e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enzyme thymidylate synthase (TSase), an important chemotherapeutic drug target, catalyzes the formation of 2'-deoxythymidine-5'-monophosphate (dTMP), a precursor of one of the DNA building blocks. TSase catalyzes a multi-step mechanism that includes the abstraction of a proton from the C5 of the substrate 2'-deoxyuridine-5'-monophosphate (dUMP). Previous studies on ecTSase proposed that an active-site residue, Y94 serves the role of the general base abstracting this proton. However, since Y94 is neither very basic, nor connected to basic residues, nor located close enough to the pyrimidine proton to be abstracted, the actual identity of this base remains enigmatic. Based on crystal structures, an alternative hypothesis is that the nearest potential proton-acceptor of C5 of dUMP is a water molecule that is part of a hydrogen bond (H-bond) network comprised of several water molecules and several protein residues including H147, E58, N177, and Y94. Here, we examine the role of the residue Y94 in the proton abstraction step by removing its hydroxyl group (Y94F mutant). We investigated the effect of the mutation on the temperature dependence of intrinsic kinetic isotope effects (KIEs) and found that these KIEs are more temperature dependent than those of the wild-type enzyme (WT). These results suggest that the phenolic -OH of Y94 is a component of the transition state for the proton abstraction step. The findings further support the hypothesis that no single functional group is the general base, but a network of bases and hydroxyls (from water molecules and tyrosine) sharing H-bonds across the active site can serve the role of the general base to remove the pyrimidine proton.
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Affiliation(s)
- Ananda K Ghosh
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Zahidul Islam
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Jonathan Krueger
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Thelma Abeysinghe
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Amnon Kohen
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA.
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Islam Z, Strutzenberg TS, Gurevic I, Kohen A. Concerted versus stepwise mechanism in thymidylate synthase. J Am Chem Soc 2014; 136:9850-3. [PMID: 24949852 PMCID: PMC4105062 DOI: 10.1021/ja504341g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thymidylate synthase (TSase) catalyzes the intracellular de novo formation of thymidylate (a DNA building block) in most living organisms, making it a common target for chemotherapeutic and antibiotic drugs. Two mechanisms have been proposed for the rate-limiting hydride transfer step in TSase catalysis: a stepwise mechanism in which the hydride transfer precedes the cleavage of the covalent bond between the enzymatic cysteine and the product and a mechanism where both happen concertedly. Striking similarities between the enzyme-bound enolate intermediates formed in the initial and final step of the reaction supported the first mechanism, while QM/MM calculations favored the concerted mechanism. Here, we experimentally test these two possibilities using secondary kinetic isotope effect (KIE), mutagenesis study, and primary KIEs. The findings support the concerted mechanism and demonstrate the critical role of an active site arginine in substrate binding, activation of enzymatic nucleophile, and the hydride transfer studied here. The elucidation of this reduction/substitution sheds light on the critical catalytic step in TSase and may aid future drug or biomimetic catalyst design.
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Affiliation(s)
- Zahidul Islam
- Department of Chemistry, The University of Iowa , Iowa City, Iowa 52242-1727, United States
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Arvizu-Flores AA, Aispuro-Hernandez E, Garcia-Orozco KD, Varela-Romero A, Valenzuela-Soto E, Velazquez-Contreras EF, Rojo-Domínguez A, Yepiz-Plascencia G, Maley F, Sotelo-Mundo RR. Functional identity of the active sites of crustacean and viral thymidylate synthases. Comp Biochem Physiol C Toxicol Pharmacol 2009; 150:406-13. [PMID: 19559812 DOI: 10.1016/j.cbpc.2009.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 06/15/2009] [Accepted: 06/16/2009] [Indexed: 12/01/2022]
Abstract
Thymidylate synthase (TS) catalyzes the synthesis of deoxythymidine monophosphate (dTMP), which is an essential precursor for DNA synthesis. The rationale underlying drug design is to identify compounds that differentially inhibit a viral or parasite enzyme vs. the host homologue. We studied the TS of the white spot syndrome virus (WSSV TS) and the corresponding TS from the host, the marine invertebrate shrimp Litopenaeus vannamei. TS is the only de novo source of dTMP and is essential for host and viral DNA replication. To establish proof of principle, we cloned a full-length TS cDNA from the white shrimp L. vannamei (shrimp TS) that corresponds to a deduced sequence of 289 amino acids and over-expressed it to study inhibition of both shrimp and viral TSs. Steady-state kinetic parameters for both TSs are similar, and dissociation (K(d)) or half maximal inhibitory concentration constants (IC(50)) did not show differential inhibition between the folate analogues. Differences in their amino acid sequence are not reflected in theoretical molecular models of both TSs, since both appear to have identical active sites. These results suggest that the eukaryotic TS active site is very constrained into the functional residues involved in reductive methylation of 2'-deoxyuridine-5'-monophosphate (dUMP).
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Affiliation(s)
- Aldo A Arvizu-Flores
- Centro de Investigación en Alimentación y Desarrollo (CIAD), Hermosillo, Sonora, Mexico
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Zhang N, Yin Y, Xu SJ, Chen WS. 5-Fluorouracil: mechanisms of resistance and reversal strategies. Molecules 2008; 13:1551-69. [PMID: 18794772 PMCID: PMC6244944 DOI: 10.3390/molecules13081551] [Citation(s) in RCA: 470] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 07/01/2008] [Accepted: 07/15/2008] [Indexed: 11/24/2022] Open
Abstract
The purpose of this work is to review the published studies on the mechanisms of action and resistance of 5-fluorouracil. The review is divided into three main sections: mechanisms of anti-tumor action, studies of the resistance to the drug, and procedures for the identification of new genes involved in resistance with microarray techniques. The details of the induction and reversal of the drug resistance are also described.
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Affiliation(s)
- Ning Zhang
- Department of Orthopaedics, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, #88 Jiefang Road, Hangzhou, 310009, P.R. China; E-mail:
| | - Ying Yin
- Institute of Clinical Research, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, #3 East Qingchun Road, Hangzhou, 310016, P.R. China; E-mails: ;
| | - Sheng-Jie Xu
- Institute of Clinical Research, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, #3 East Qingchun Road, Hangzhou, 310016, P.R. China; E-mails: ;
| | - Wei-Shan Chen
- Department of Orthopaedics, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, #88 Jiefang Road, Hangzhou, 310009, P.R. China; E-mail:
- Author to whom correspondence should be addressed; E-Mail:
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