1. Anal Biochem. 2010 Jan 15;396(2):250-6. Epub 2009 Sep 18.

Comparison of methods for measuring oxygen consumption in tumor cells in vitro.

Diepart C, Verrax J, Calderon PB, Feron O, Jordan BF, Gallez B.

Laboratory of Biomedical Magnetic Resonance, Louvain Drug Research Institute,
Université catholique de Louvain, B-1200 Brussels, Belgium.

The oxygen consumption rate of tumor cells affects tumor oxygenation and response
to therapies. Highly sensitive methods for determining cellular oxygen
consumption are, therefore, needed to identify treatments that can modulate this 
parameter. We compared the performances of three different methods for measuring 
cellular oxygen consumption: electron paramagnetic resonance (EPR) oximetry, the 
Clark electrode, and the MitoXpress fluorescent assay. To compare the assays, we 
used K562 cells in the presence of rotenone and hydrocortisone, compounds that
are known to inhibit the mitochondrial electron transport chain to different
extents. The EPR method was the only one that could identify both rotenone and
hydrocortisone as inhibitors of tumor cell oxygen consumption. The Clark
electrode and the fluorescence assay demonstrated a significant decrease in
cellular oxygen consumption after administration of the most potent inhibitor
(rotenone) but failed to show any significant effect of hydrocortisone. EPR
oximetry is, therefore, the most sensitive method for identifying inhibitors of
oxygen consumption on cell assays, whereas the Clark electrode offers the unique 
opportunity to add external compounds during experiments and still shows great
sensitivity in studying enzyme and chemical reactions that consume oxygen
(non-cell assays). Finally, the MitoXpress fluorescent assay has the advantage of
a high-sample throughput and low bulk requirements but at the cost of a lower
sensitivity.

PMID: 19766582 [PubMed - in process]