CYP450 Enzymes Effect Oxygen-Dependent Reduction of Azide-Based Fluorogenic Dyes.
Azide-containing compounds have broad utility in organic synthesis and chemical biology. Their use as powerful tools for the labeling of biological systemsin vitrohas enabled insights into complex cellular functions. To date, fluorogenic azide-containing compounds have primarily been employed in the context of click chemistry and as sensitive functionalities for hydrogen sulfide detection. Here, we report an alternative use of this functionality: as fluorogenic probes for the detection of depleted oxygen levels (hypoxia). Oxygen is imperative to all life forms, and probes that enable quantification of oxygen tension are of high utility in many areas of biology. Here we demonstrate the ability of an azide-based dye to image hypoxia in a range of human cancer cell lines. We have found that cytochrome P450 enzymes are able to reduce these probes in an oxygen-dependent manner, while hydrogen sulfide does not play an important role in their reduction. These data indicate that the azide group is a new bioreductive functionality that can be employed in prodrugs and dyes. We have uncovered a novel mechanism for the cellular reduction of azides, which has implications for the use of click chemistry in hypoxia.
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.; CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, U.K.
Liam J
LJ
O'Connor
CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford , Old Road Campus Research Building, Oxford, OX3 7DQ, U.K.
Ishna N
IN
Mistry
Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford, OX1 3TA, U.K.
Sarah L
SL
Collins
CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford , Old Road Campus Research Building, Oxford, OX3 7DQ, U.K.
Lisa K
LK
Folkes
CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford , Old Road Campus Research Building, Oxford, OX3 7DQ, U.K.
Graham
G
Brown
Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford, OX1 3TA, U.K.
Stuart J
SJ
Conway
CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford , Old Road Campus Research Building, Oxford, OX3 7DQ, U.K.
Ester M
EM
Hammond