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Science (New York, N.Y.) Apr 2021Mutations in the or tumor suppressor genes predispose individuals to breast and ovarian cancer. In the clinic, these cancers are treated with inhibitors that target...
Mutations in the or tumor suppressor genes predispose individuals to breast and ovarian cancer. In the clinic, these cancers are treated with inhibitors that target poly(ADP-ribose) polymerase (PARP). We show that inhibition of DNPH1, a protein that eliminates cytotoxic nucleotide 5-hydroxymethyl-deoxyuridine (hmdU) monophosphate, potentiates the sensitivity of -deficient cells to PARP inhibitors (PARPi). Synthetic lethality was mediated by the action of SMUG1 glycosylase on genomic hmdU, leading to PARP trapping, replication fork collapse, DNA break formation, and apoptosis. -deficient cells that acquired resistance to PARPi were resensitized by treatment with hmdU and DNPH1 inhibition. Because genomic hmdU is a key determinant of PARPi sensitivity, targeting DNPH1 provides a promising strategy for the hypersensitization of -deficient cancers to PARPi therapy.
Topics: Antineoplastic Agents; Apoptosis; CRISPR-Cas Systems; Cell Line, Tumor; DNA Breaks, Double-Stranded; DNA Replication; DNA, Neoplasm; Deoxycytidine Monophosphate; Deoxyuracil Nucleotides; Drug Resistance, Neoplasm; Genes, BRCA1; Humans; Hydrolysis; N-Glycosyl Hydrolases; Phthalazines; Piperazines; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins; Synthetic Lethal Mutations; Thymidine; Uracil-DNA Glycosidase
PubMed: 33833118
DOI: 10.1126/science.abb4542 -
Molecular Aspects of Medicine Feb 2017Thymidylate (dTMP) biosynthesis plays an essential and exclusive function in DNA synthesis and proper cell division, and therefore has been an attractive therapeutic... (Review)
Review
Thymidylate (dTMP) biosynthesis plays an essential and exclusive function in DNA synthesis and proper cell division, and therefore has been an attractive therapeutic target. Folate analogs, known as antifolates, and nucleotide analogs that inhibit the enzymatic action of the de novo thymidylate biosynthesis pathway and are commonly used in cancer treatment. In this review, we examine the mechanisms by which the antifolate 5-fluorouracil, as well as other dTMP synthesis inhibitors, function in cancer treatment in light of emerging evidence that dTMP synthesis occurs in the nucleus. Nuclear localization of the de novo dTMP synthesis pathway requires modification of the pathway enzymes by the small ubiquitin-like modifier (SUMO) protein. SUMOylation is required for nuclear localization of the de novo dTMP biosynthesis pathway, and disruption in the SUMO pathway inhibits cell proliferation in several cancer models. We summarize evidence that the nuclear localization of the dTMP biosynthesis pathway is a critical factor in the efficacy of antifolate-based therapies that target dTMP synthesis.
Topics: Animals; Cell Nucleus; Drug Resistance, Neoplasm; Fluorouracil; Humans; Neoplasms; Sumoylation; Thymidine Monophosphate
PubMed: 27876557
DOI: 10.1016/j.mam.2016.11.005 -
Microorganisms Jun 2022Tuberculosis (TB) is the oldest human infection disease. Mortality from TB significantly decreased in the 20th century, because of vaccination and the widespread use of... (Review)
Review
Tuberculosis (TB) is the oldest human infection disease. Mortality from TB significantly decreased in the 20th century, because of vaccination and the widespread use of antibiotics. However, about a third of the world's population is currently infected with () and the death rate from TB is about 1.4-2 million people per year. In the second half of the 20th century, new extensively multidrug-resistant strains of were identified, which are steadily increasing among TB patients. Therefore, there is an urgent need to develop new anti-TB drugs, which remains one of the priorities of pharmacology and medicinal chemistry. The antimycobacterial activity of nucleoside derivatives and analogues was revealed not so long ago, and a lot of studies on their antibacterial properties have been published. Despite the fact that there are no clinically used drugs based on nucleoside analogues, some progress has been made in this area. This review summarizes current research in the field of the design and study of inhibitors of mycobacteria, primarily .
PubMed: 35889017
DOI: 10.3390/microorganisms10071299 -
Journal of Bacteriology Sep 1975p-Aminobenzoate (PABA) synthase from Bacillus subtilis is an aggregate composed of two nonidentical subunits and has the following properties. (i) In crude extracts this...
p-Aminobenzoate (PABA) synthase from Bacillus subtilis is an aggregate composed of two nonidentical subunits and has the following properties. (i) In crude extracts this enzyme catalyzes the formation of PABA in the presence of chorismate and either glutamine (amidotransferase) or ammonia (aminase). The amidotransferase activity is about 5- to 10-fold higher than the aminase activity and is stable for at least 1 week when frozen at -70 C. (II) Although no divalent cation requirement could be demonstrated with crude extracts, 2 mM ethylene-diaminetetraacetic acid completely inhibits both activities. (iii) After ammonium sulfate fractionation both the aminase and amidotransferase activities require Mg2+ and guanosine in addition to the substrates indicated above for optimal activity. The guanosine requirement can be replaced by guanosine 5'-monophosphate, guanosine 5'-diphosphate, and guanosine 5'-triphosphate but not by guanine, adenosine 5'-triphosphate, uridine 5'-triphosphate, cytidine 5'-triphosphate, thymidine 5'-triphosphate, inorganic phosphate, and phosphoribosylpyrophosphate. Furthermore, at a pH above 7.4 or below 6.4 activity is rapidly lost a 4 C, or -60 C. (IV) The enzyme is composed of two non-identical subunits, designated subunit A and subunit X. Subunit A has an estimated molecular weight of 31,000, whereas subunit X has an estimated molecular weight of 19,000. Subunit A has aminase activity but no amidotransferase activity; a mutation at the pabA locus results in the loss of PABA synthase activity. Subunit X, which is also a component of the anthranilate synthase complex, has no PABA synthase activity itself but complexes with subunit A to give an AX aggregate that can use glutamine as a substrate. (v) The molecular weight of the AX complex has been estimated at 50,000, suggesting a 1:1 ratio of subunits. (vi) The enzyme is readily associated and dissociated.
Topics: Aminobenzoates; Ammonia; Bacillus subtilis; Chorismic Acid; Dose-Response Relationship, Drug; Edetic Acid; Glutamine; Guanosine; Guanosine Triphosphate; Hydrogen-Ion Concentration; Magnesium; Molecular Weight; Transaminases
PubMed: 239922
DOI: 10.1128/jb.123.3.1131-1138.1975 -
The Journal of Experimental Medicine Feb 2019Folate metabolism is crucial for many biochemical processes, including purine and thymidine monophosphate (dTMP) biosynthesis, mitochondrial protein translation, and... (Review)
Review
Folate metabolism is crucial for many biochemical processes, including purine and thymidine monophosphate (dTMP) biosynthesis, mitochondrial protein translation, and methionine regeneration. These biochemical processes in turn support critical cellular functions such as cell proliferation, mitochondrial respiration, and epigenetic regulation. Not surprisingly, abnormal folate metabolism has been causally linked with a myriad of diseases. In this review, we provide a historical perspective, delve into folate chemistry that is often overlooked, and point out various missing links and underdeveloped areas in folate metabolism for future exploration.
Topics: Animals; Cell Proliferation; Epigenesis, Genetic; Folic Acid; Humans; Methionine; Mitochondria; Oxygen Consumption; Protein Biosynthesis; Thymidine Monophosphate
PubMed: 30587505
DOI: 10.1084/jem.20181965 -
International Journal of Medical... Mar 2023Staphylococcus aureus (S. aureus) is one of the critical clinical pathogens which can cause multiple diseases ranging from skin infections to fatal sepsis. S. aureus is... (Review)
Review
Staphylococcus aureus (S. aureus) is one of the critical clinical pathogens which can cause multiple diseases ranging from skin infections to fatal sepsis. S. aureus is generally considered to be an extracellular pathogen. However, more and more evidence has shown that S. aureus can survive inside various cells. Folate plays an essential role in multiple life activities, including the conversion of serine and glycine, the remethylation of homocysteine to methionine, and the de novo synthesis of purine /dTMP, et al. More and more studies reported that S. aureus intracellular infection requires the involvement of folate metabolism. This review focused on the mechanisms of folate metabolism and related substances affecting S. aureus infection. Loss of tetrahydrofolic acid (THF)-dependent dTMP directly inhibits the nucleotide synthesis pathway of the S. aureus due to pabA deficiency. Besides, trimethoprim-sulfamethoxazole (TMP/SMX), a potent antibiotic that treats S. aureus infections, interferes in the process of the folate mechanism and leads to the production of thymidine-dependent small-colony variants (TD-SCVs). In addition, S. aureus is resistant to lysostaphin in the presence of serine hydroxymethyltransferase (SHMT). We provide new insights for understanding the molecular pathogenesis of S. aureus infection.
Topics: Humans; Staphylococcus aureus; Thymidine Monophosphate; Staphylococcal Infections; Trimethoprim, Sulfamethoxazole Drug Combination; Folic Acid
PubMed: 36841056
DOI: 10.1016/j.ijmm.2023.151577 -
Current Topics in Medicinal Chemistry 2012Antiviral chemotherapy often relies on nucleoside analogues, which, once phophorylated by intracellular kinases, target viral polymerases impeding DNA synthesis. In... (Review)
Review
Antiviral chemotherapy often relies on nucleoside analogues, which, once phophorylated by intracellular kinases, target viral polymerases impeding DNA synthesis. In contrast, nucleoside analogues are much less explored as antibacterial drugs. Thymidine monophosphate kinase from Mycobacterium tuberculosis (TMPKmt), which is essential to DNA replication, was selected as a promising target for the design of new inhibitors. This review describes stepwise modifications of the TMPKmt substrate, guided by the feedback of enzyme assays and crystallographic analysis to afford potent enzyme inhibitors some of which also exhibited antitubercular activity. More importantly, several of the reported thymidine analogues provided a deeper understanding of the structure and catalytic mechanism of this intriguing enzyme.
Topics: Antitubercular Agents; Drug Design; Enzyme Inhibitors; Humans; Models, Molecular; Molecular Structure; Mycobacterium tuberculosis; Nucleoside-Phosphate Kinase; Structure-Activity Relationship
PubMed: 22283813
DOI: 10.2174/156802612799984580