title: In vitro assessment of nucleoside analogs in multiple myeloma.
abstract: OBJECTIVE
  To identify nucleoside analogs that may be effective for multiple myeloma (MM), we tested fludarabine, clofarabine, arabinosylguanine, cytarabine, troxacitabine, and gemcitabine in MM cell lines.
  
  
  METHODS
  We employed biologic and biochemical assays in MM cell lines to evaluate the clinical potential of these nucleoside analogs.
  
  
  RESULTS
  Among these purine and pyrimidine nucleoside analogs, fludarabine, clofarabine and gemcitabine were the most potent. MM cell lines, resistant to commonly used chemotherapeutic agents for this disease, were more sensitive to gemcitabine with an IC50 in the nanomolar range. The greater cytotoxicity of gemcitabine in MM cells was consistent with greater accumulation of gemcitabine triphosphate, the major cytotoxic metabolite of this drug. MM.1S cells accumulated >100 microM gemcitabine triphosphate but accumulated <20 microM of the other analogs as the respective triphosphates. In addition incubation with gemcitabine resulted in inhibition of DNA synthesis. Incubation with 25, 50 or 100 nM gemcitabine resulted in a dose- and time-dependent increase in the cell population with a subG1 DNA content indicative of apoptosis.
  
  
  CONCLUSIONS
  These results suggest that gemcitabine is a potent nucleoside analog in MM cell lines including cell types resistant to other chemotherapeutic agents. The greater activity of gemcitabine compared to other analogs seems to be due to favorable metabolism of this agent.
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA. n-krett@northwestern.edu
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Krett
authors.forename: Mary
authors.initials: M
authors.lastname: Ayres
authors.forename: Chadi
authors.initials: C
authors.lastname: Nabhan
authors.forename: Chunguang
authors.initials: C
authors.lastname: Ma
authors.forename: Billie
authors.initials: B
authors.lastname: Nowak
authors.forename: Steffan
authors.initials: S
authors.lastname: Nawrocki
authors.forename: Steven T
authors.initials: ST
authors.lastname: Rosen
authors.forename: Varsha
authors.initials: V
authors.lastname: Gandhi
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D009101:Multiple Myeloma / Q000473:pathology*; D009705:Nucleosides; D014407:Tumor Cells, Cultured; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D009705:Nucleosides; D003841:Deoxycytidine; D000093542:Gemcitabine