Transgenic Animal Models to Visualize Cancer-Related Cellular Processes by Bioluminescence Imaging

Abstract

Preclinical animal models are valuable tools to improve treatments of malignant diseases, being an intermediate step of experimentation between cell culture and human clinical trials. Among different animal models frequently used in cancer research are mouse and, more recently, zebrafish models. Indeed, most of the cellular pathways are highly conserved between human, mouse and zebrafish, thus rendering these models very attractive. Recently, several transgenic reporter mice and zebrafishes have been generated in which the luciferase reporter gene are placed under the control of a promoter whose activity is strictly related to specific cancer cellular processes. Other mouse models have been generated by the cDNA luciferase knockin in the locus of a gene whose expression/activity has increased in cancer. Using BioLuminescence Imaging (BLI), we have now the opportunity to spatiotemporal visualize cell behaviors, among which proliferation, apoptosis, migration and immune responses, in any body district in living animal in a time frame process. We provide here a review of the available models to visualized cancer and cancer-associated events in living animals by BLI and as they have been successful in identifying new stages of early tumor progression, new interactions between different tissues and new therapeutic responsiveness.

How to Select Firefly Luciferin Analogues for In Vivo Imaging

“…Specifically, firefly BLI has been utilized for in vivo study in numerous mouse models [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. For instance, it has been used to quantify tumor cells [ 37 ] and monitor gene expression in transgenic mouse models [ 38 ]. Now many researchers use the improved luciferase genes for the experiment in life science (e.g., luc+ , luc2 ).…”

MITO-Luc/GFP zebrafish model to assess spatial and temporal evolution of cell proliferation in vivo

“…Due to the optical transparency, cell proliferation can be analyzed in the whole-mount embryo by GFP 57 , while the detection of GFP in live adult animals is not achievable, due to the lack of skin transparency; therefore light detection is limited to organs and tissues near the body surface. In contrast, luciferase expression from inner organs and tissues can be detected in adult zebrafish 20 . Interestingly, the zebrafish transparent mutant strain 16 if crossed with our strain, will make it possible to improve the signal-to-noise ratio and possibly enable the use GFP fluorescence also in adult zebrafish.…”

“…The luciferase-luciferine reaction can be linked to a specific biological process allowing its real-time non-invasive imaging. Non-invasive BLI has been widely used in mice to monitor gene expression 18 , bacterial and viral infections 19 , as well as cell proliferation and transformation 20 . This technique allows the serial quantification of spatial and temporal evolution of the process of interest in the same animal 19 .…”

Correlated Multimodal Imaging in Life Sciences: Expanding the Biomedical Horizon

“…Fluorescent images are co-registered to hybrid images using brightfield or X-ray anatomical imaging. While OI was initially limited to 2D imaging, several technologies have been developed in recent years which allow 3D tomographic imaging in combination with morphological imaging based on CT. For preclinical OI, firefly luciferase is the most commonly used transgene allowing longitudinal studies on e.g., promoter activity in transgenic mice, growth and dissemination of implanted tumors [46] or biodistribution and proliferation of organisms in infection models [47]. Kuo et al published the first tomographic imaging setup for luciferase imaging, termed diffuse luminescence imaging tomography (DLIT) [48].…”