HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Nuclear overexpression of NADH:cytochrome b5 reductase activity increases the cytotoxicity of mitomycin C (MC) and the total number of MC-DNA adducts in Chinese hamster ovary cells.

Abstract
NADH:cytochrome b(5) reductase (FpD) is an enzyme capable of converting the prodrug mitomycin C (MC) into a DNA alkylating agent via reduction of its quininone moiety. In this study, Chinese hamster ovary (CHO) cells were transfected with a cDNA encoding rat FpD. Despite the demonstrated ability of this enzyme to reduce MC in vitro, a modest 5-fold level of overexpression of FpD activity in CHO cells did not increase the cytotoxicity of the drug over that seen with the parental cell line under either aerobic or hypoxic conditions. When the enzyme, which is predominantly localized in the mitochondria, was instead directed to the nucleus of cells by the fusion of the SV40 large T antigen nuclear localization signal sequence to the amino terminus of an FpD gene that lacked the membrane anchor domain, drug sensitivity was significantly enhanced at all concentrations of MC examined (2-10 microm) under both aerobic and hypoxic conditions, with greater cell kill occurring under hypoxia. The marked increase in drug sensitivity under hypoxia at 10 microm MC corresponded to a measurable increase in total MC-DNA adducts at the same concentration. The results indicate that the cytotoxicity of MC is modulated by the subcellular location of FpD, with greater cell kill occurring when bioactivation occurs in the proximity of its target, nuclear DNA.
AuthorsKathleen M Holtz, Sara Rockwell, Maria Tomasz, Alan C Sartorelli
JournalThe Journal of biological chemistry (J Biol Chem) Vol. 278 Issue 7 Pg. 5029-34 (Feb 14 2003) ISSN: 0021-9258 [Print] United States
PMID12424239 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)
Chemical References
  • Antibiotics, Antineoplastic
  • DNA Adducts
  • Mitomycin
  • Cytochrome Reductases
  • Cytochrome-B(5) Reductase
Topics
  • Animals
  • Antibiotics, Antineoplastic (pharmacology)
  • CHO Cells
  • Cell Death (drug effects)
  • Cell Nucleus (metabolism)
  • Cricetinae
  • Cytochrome Reductases (biosynthesis, genetics)
  • Cytochrome-B(5) Reductase
  • DNA Adducts (drug effects, genetics)
  • Drug Resistance (genetics)
  • Gene Expression Regulation, Enzymologic
  • Mitomycin (pharmacology)
  • Rats

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: