Journal Article


Robert O'Connor
Martin Clynes
Ian J Stratford
Kaye J Williams
Vanesa G Martinez



microsomes nadp reactive oxygen species antimetabolites antineoplastic humans pharmacology metabolism nadph ferrihemoprotein reductase fluorouracil physiology mitomycin antibiotics antineoplastic female blotting western genetics drug therapy cell line tumor breast neoplasms transfection antineoplastic agents phytogenic vincristine glutathione cell survival biosynthesis

Overexpression of cytochrome P450 NADPH reductase sensitises MDA 231 breast carcinoma cells to 5-fluorouracil: possible mechanisms involved. (2007)

Abstract Activity of cytochromes P450 is highly dependent on cytochrome P450 NADPH reductase (P450R), but this enzyme can also metabolise drugs on its own. MDA 231 breast adenocarcinoma cells transfected with human P450R (MDA R4) or an empty vector (MDA EV) were exposed to a series of commonly used chemotherapeutic drugs. Overexpression of P450R did not affect cell sensitivity to cisplatin, mitoxantrone, paclitaxel, docetaxel, vincristine or etoposide. However, MDA R4 cells showed increased sensitivity to mitomycin C (6.6-fold) and also to 5-fluorouracil (2.8-fold). In vitro toxicity assays where mitomycin C, 5-fluorouracil and vincristine were preincubated with microsomes expressing recombinant P450R showed that this effect was not a result of direct metabolism by P450R. Levels of NADPH were considerably decreased in MDA R4 as compared to MDA EV cells, while reactive oxygen species (ROS) production was increased in MDA R4 cells in basal conditions, showing no significant further increase after treatment with mitomycin C or 5-fluorouracil. P450R overexpression appears therefore to be detrimental to MDA 231 cells, depleting NADPH and increasing ROS levels; the increased oxidative stress observed in MDA R4 cells might explain the enhanced sensitivity to 5-fluorouracil. Expression of this enzyme in tumour cells might therefore modulate response to 5-fluorouracil.
Collections Ireland -> Dublin City University -> PubMed

Full list of authors on original publication

Robert O'Connor, Martin Clynes, Ian J Stratford, Kaye J Williams, Vanesa G Martinez

Experts in our system

Robert O'Connor
Dublin City University
Total Publications: 74
Martin Clynes
Dublin City University
Total Publications: 232
Vanesa G Martinez
Trinity College Dublin
Total Publications: 8