title: Targeting nuclear thymidylate biosynthesis.
abstract: 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.
authors.affiliation: Graduate Field of Biochemistry, Molecular and Cellular Biology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: James
authors.initials: J
authors.lastname: Chon
authors.affiliation: Graduate Field of Biochemistry, Molecular and Cellular Biology, Cornell University, Ithaca, NY 14853, USA; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Stover
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA. Electronic address: mas246@cornell.edu.
authors.forename: Martha S
authors.initials: MS
authors.lastname: Field
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D005472:Fluorouracil / Q000009:adverse effects; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology; D058207:Sumoylation; D013938:Thymidine Monophosphate / Q000096:biosynthesis*
chemical_list: D013938:Thymidine Monophosphate; D005472:Fluorouracil
keywords: Antifolate; Folate-mediated one-carbon metabolism; Nuclear thymidylate synthesis; Sumoylation; Thymidylate synthase