title: Biosynthetic ganciclovir triphosphate: its isolation and characterization from ganciclovir-treated herpes simplex thymidine kinase-transduced murine cells.
abstract: A method is described for the preparation of ganciclovir triphosphate (GCV-TP) using murine colon cancer cells (MC38) transduced with the herpes simplex virus-thymidine kinase (MC38/HSV-tk). Murine cells transduced with viral-tk contain required viral and host enzymes needed for complete cellular synthesis of this potent antiviral metabolite. Dose response studies showed optimal intracellular levels of GCV-TP occurred after exposure of MC38/HSV-tk cells to 300 microM ganciclovir for 24 h producing 7.5 nmol GCV-TP/10(6) cells. This reflects cellular accumulation of GCV-TP to levels 25-fold greater than the medium concentration of parent drug. A simple isolation scheme included methanolic extraction and anion-exchange chromatography to recover the target triphosphate. Mass spectral analysis and selective enzyme degradation provided structural confirmation of the purified product. Biological activity of the purified GCV-TP was demonstrated by competitive inhibition experiments using human DNA polymerase alpha and HSV DNA polymerase that showed substantially greater sensitivity for the viral polymerase in agreement with previous reports. The GCV-TP obtained was further used to enzymatically prepare GCV mono- and diphosphate in high yield. This method provides an easily scalable means of preparing milligram amounts of the triphosphates of pharmacologically active acyclic nucleosides like ganciclovir.
authors.affiliation: Department of Clinical Pharmacology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Agbaria
authors.forename: F
authors.initials: F
authors.lastname: Candotti
authors.forename: J A
authors.initials: JA
authors.lastname: Kelley
authors.forename: Z
authors.initials: Z
authors.lastname: Hao
authors.forename: D G
authors.initials: DG
authors.lastname: Johns
authors.forename: D A
authors.initials: DA
authors.lastname: Cooney
authors.forename: R M
authors.initials: RM
authors.lastname: Blaese
authors.forename: H
authors.initials: H
authors.lastname: Ford
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism; D000818:Animals; D000838:Anions; D000998:Antiviral Agents / Q000494:pharmacology; D001667:Binding, Competitive; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003110:Colonic Neoplasms / Q000378:metabolism; D004256:DNA Polymerase I / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015774:Ganciclovir / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology*; D006561:Herpes Simplex / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D013058:Mass Spectrometry; D051379:Mice; D008956:Models, Chemical; D013937:Thymidine Kinase / Q000378:metabolism; D013997:Time Factors; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D000838:Anions; D000998:Antiviral Agents; C092309:ganciclovir triphosphate; D013937:Thymidine Kinase; D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase; D015774:Ganciclovir