Molecular-genetic imaging based on reporter gene expression.
Molecular imaging includes proteomic, metabolic, cellular biologic process, and genetic imaging. In a narrow sense, molecular imaging means genetic imaging and can be called molecular-genetic imaging. Imaging reporter genes play a leading role in molecular-genetic imaging. There are 3 major methods of molecular-genetic imaging, based on optical, MRI, and nuclear medicine modalities. For each of these modalities, various reporter genes and probes have been developed, and these have resulted in successful transitions from bench to bedside applications. Each of these imaging modalities has its unique advantages and disadvantages. Fluorescent and bioluminescent optical imaging modalities are simple, less expensive, more convenient, and more user friendly than other imaging modalities. Another advantage, especially of bioluminescence imaging, is its ability to detect low levels of gene expression. MRI has the advantage of high spatial resolution, whereas nuclear medicine methods are highly sensitive and allow data from small-animal imaging studies to be translated to clinical practice. Moreover, multimodality imaging reporter genes will allow us to choose the imaging technologies that are most appropriate for the biologic problem at hand and facilitate the clinical application of reporter gene technologies. Reporter genes can be used to visualize the levels of expression of particular exogenous and endogenous genes and several intracellular biologic phenomena, including specific signal transduction pathways, nuclear receptor activities, and protein-protein interactions. This technique provides a straightforward means of monitoring tumor mass and can visualize the in vivo distributions of target cells, such as immune cells and stem cells. Molecular imaging has gradually evolved into an important tool for drug discovery and development, and transgenic mice with an imaging reporter gene can be useful during drug and stem cell therapy development. Moreover, instrumentation improvements, the identification of novel targets and genes, and imaging probe developments suggest that molecular-genetic imaging is likely to play an increasingly important role in the diagnosis and therapy of cancer.
Department of Nuclear Medicine, Cancer Research Institute, Tumor Immunity Medical Research Center, College of Medicine, Seoul National University, Seoul, Korea.
Joo Hyun
JH
Kang
June-Key
JK
Chung
D000818:Animals; D030801:Animals, Genetically Modified; D017690:Cell Transplantation; D003952:Diagnostic Imaging / Q000295:instrumentation / Q000379:methods*; D004353:Drug Evaluation, Preclinical; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D015316:Genetic Therapy; D006801:Humans; D008163:Luminescent Measurements / Q000295:instrumentation; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D051379:Mice; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography / Q000295:instrumentation; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals