Article

Nitroreductase, a Near-Infrared Reporter Platform for In Vivo Time-Domain Optical Imaging of Metastatic Cancer

Institute of Medicine/Section of Hematology, University of Bergen.
Cancer Research (Impact Factor: 9.28). 12/2012; 73(4). DOI: 10.1158/0008-5472.CAN-12-2649
Source: PubMed

ABSTRACT The ability to visualize reporter gene expression in vivo has revolutionized all facets of biological investigation and none more so than imaging applications in oncology. Near-infrared reporter gene imaging may facilitate more accurate evaluation of chemotherapeutic response in preclinical models of orthotopic and metastatic cancers. We report the development of a cell permeable, quenched cyanine probe (CytoCy5S), which is reduced by Escherichia coli nitroreductase (NTR) resulting in a near-infrared fluorescent product. Time-domain molecular imaging of NTR/CytoCy5S reporter platform permitted non-invasive monitoring of disease progression in orthotopic xenografts of disseminated leukemia, lung and metastatic breast cancer. This methodology facilitated therapeutic evaluation of nitroreductase gene-directed enzymatic prodrug therapy with conventional metronidazole antibiotics. These studies demonstrate NTR/CytoCy5S as a near-infrared gene reporter system with broad preclinical and prospective clinical applications within imaging, and gene therapy, of cancer.

Full-text

Available from: Emmet Mc Cormack, Jun 03, 2015
0 Followers
 · 
266 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The application of time domain (TD) fluorescence lifetime multiplexing for the detection of fluorescent proteins (FPs) in whole animals, in the presence of a strong background tissue autofluorescence and excitation light leakage is discussed. Tissue autofluorescence (AF) exhibits a nonexponential temporal response, distinct from the mono-exponential decay of FPs. This allows a direct separation of FP fluorescence from AF using a dual basis function approach. We establish the detection limits of this approach using in vitro and in vivo measurements. We also demonstrate, using an experimental model of lymph node metastasis, that FP-AF lifetime multiplexing provides a greater than 30-fold improvement in contrast-to-background ratio compared with continuous wave data. In addition, we show that TD detection can simultaneously discriminate between up to three red shifted FPs placed under the skin of a nude mouse based on their distinct fluorescence lifetimes.
    Journal of Biomedical Optics 04/2014; 19(4):46005. DOI:10.1117/1.JBO.19.4.046005 · 2.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Metastatic cancers have historically been difficult to treat. However, metastatic tumors have been found to have high levels of reactive oxygen species such as hydrogen peroxide (H2O2), supporting the hypothesis that a prodrug could be activated by intracellular H2O2 and lead to a potential antimetastatic therapy. In this study, prodrug 7 was designed to be activated by H2O2-mediated boronate oxidation, resulting in activation of the fluorophore for detection and release of the therapeutic agent, SN-38. Drug release from prodrug 7 was investigated by monitoring fluorescence after addition of H2O2 to the cancer cells. Prodrug 7 activated by H2O2, selectively inhibited tumor cell growth. Furthermore, intratracheally administered prodrug 7 showed effective antitumor activity in a mouse model of metastatic lung disease. Thus, this H2O2-responsive prodrug has therapeutic potential as a novel treatment for metastatic cancer via cellular imaging with fluorescence as well as selective release of the anticancer drug, SN-38.
    Journal of the American Chemical Society 09/2014; 136(39). DOI:10.1021/ja5077684 · 11.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cellular communication drives diverse aspects of organismal biology ranging from immune function to memory formation. The mechanisms by which cells transact information in vivo, though, are not completely understood. This is due, in part, to a lack of tools for observing collections of cells in their native habitats. New optical probes are being crafted to image networks of cell-cell interactions (i.e., 'interactomes') in tissues and live organisms. Examples of these probes-and their use in visualizing cell contacts and macroscopic cell networks-are highlighted. Copyright © 2014. Published by Elsevier Ltd.
    Current Opinion in Chemical Biology 12/2014; 24C:121-130. DOI:10.1016/j.cbpa.2014.11.006 · 7.65 Impact Factor