Citation Details

Journal Article

Cancer; Cardiology; Gene delivery vector; Gene Therapy; Imaging / Radiology; Molecular Imaging; Nuclear Medicine; Oncology; Orthopedics; Xen26

Cancer persists as one of the most devastating diseases in the world. Problems including metastasis and tumor resistance to chemotherapy and radiotherapy have seriously limited the therapeutic effects of present clinical treatments. To overcome these limitations, cancer gene therapy has been developed over the last two decades for a broad spectrum of applications, from gene replacement and knockdown to vaccination, each with different requirements for gene delivery. So far, a number of genes and delivery vectors have been investigated, and significant progress has been made with several gene therapy modalities in clinical trials. Viral vectors and synthetic liposomes have emerged as the vehicles of choice for many applications. However, both have limitations and risks that restrict gene therapy applications, including the complexity of production, limited packaging capacity, and unfavorable immunological features. While continuing to improve these vectors, it is important to investigate other options, particularly nonviral biological agents such as bacteria, bacteriophages, and bacteria-like particles. Recently, many molecular imaging techniques for safe, repeated, and high-resolution in vivo imaging of gene expression have been employed to assess vector-mediated gene expression in living subjects. In this review, molecular imaging techniques for monitoring biological gene delivery vehicles are described, and the specific use of these methods at different steps is illustrated. Linking molecular imaging to gene therapy will eventually help to develop novel gene delivery vehicles for preclinical study and support the development of future human applications.

Journal Article

Animals; Bacteroides fragilis; Diagnostic Imaging; Disease Progression; Escherichia coli; Luciferases, Bacterial; Luminescent Agents; Male; Peritoneal Lavage; Peritonitis; Rats; Rats, Wistar; Xen14

BACKGROUND Bacterial peritonitis is a life-threatening abdominal infection associated with high morbidity and mortality. The rat is a popular animal model for studying peritonitis and its treatment, but longitudinal monitoring of the progression of peritonitis in live animals has been impossible until now and thus required a large number of animals. Our objective was to develop a noninvasive in vivo imaging technique to monitor the spatiotemporal spread of bacterial peritonitis. METHODS Peritonitis was induced in 8 immunocompetent male Wistar rats by placing fibrin clots containing 5x10(8) cells of both Bacteroides fragilis (American Type Tissue Culture [ATCC)] 25,285 and bioluminescent Escherichia coli Xen14. After 1 or 2 days, infected clots were removed and open abdomen lavage was performed. In vivo bioluminescent imaging was used to monitor the spread of peritonitis. RESULTS Bioluminescent in vivo imaging showed an increase in the area of spread, and the number of E. coli tripled into the rat's abdominal cavity on day 1 after clot insertion; however, on day 2, encapsulation of the clot confined bacterial spread. Bioluminescent E. coli respread over the peritoneal cavity after lavage; within 10 days, however, in vivo imaging showed a decrease of 3-4 orders of magnitude in bacterial load. CONCLUSION Bioluminescent in vivo imaging can be effectively used to monitor the spatiotemporal behavior of the peritonitis during 3 different stages of the disease process: initiation, treatment, and follow-up. Imaging allows researchers to repeatedly image the same animal, thereby reducing variability and providing greater confidence in determining treatment efficacies for therapeutic interventions using a small number of animals.

Journal Article

Animals, B16-F10-luc2, B16F10-luc2; Base Sequence; Carcinoma, Lewis Lung/blood supply/genetics/immunology/therapy; Cell Line, Tumor; Chemokines, CXC/*genetics/*immunology; DNA Primers/genetics; Female; Gene Expression; Humans; Kidney/immunology; Male; Melanoma, Experimental/blood supply/genetics/immunology/therapy; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neoplasm Transplantation; Neoplasms, Experimental/blood supply/genetics/*immunology/*therapy; RNA, Messenger/genetics; Recombinant Proteins/genetics/immunology; Transplantation, Heterologous

We reported previously that the forced expression of the chemokine BRAK, also called CXCL14 in head and neck squamous cell carcinoma (HNSCC) cells decreased the rate of tumor formation and size of tumor xenografts compared with mock-vector treated cells in athymic nude mice or in severe combined immunodeficiency mice. This suppression occurred even though the growth rates of these cells were the same under in vitro culture conditions, suggesting that a high expression level of the gene in tumor cells is important for the suppression of tumor establishment in vivo. The aim of this study was to determine whether CXCL14/BRAK transgenic mice show resistance to tumor cell xenografts or not. CXCL14/BRAK cDNA was introduced into male C57BL/6 J pronuclei, and 10 founder transgenic mice (Tg) were obtained. Two lines of mice expressed over 10 times higher CXCL14/BRAK protein levels (14 and 11 ng/ml plasma, respectively) than normal blood level (0.9 ng/ml plasma), without apparent abnormality. The sizes of Lewis lung carcinoma and B16 melanoma cell xenografts in Tg mice were significantly smaller than those in control wild-type mice, indicating that CXCL14/BRAK, first found as a suppressor of tumor progression of HNSCC, also suppresses the progression of a carcinoma of other tissue origin. Immunohistochemical studies showed that invasion of blood vessels into tumors was suppressed in tumor xenografts of CXCL14/BRAK Tg mice. These results indicate that CXCL14/BRAK suppressed tumor cell xenografts by functioning paracrine or endocrine fashion and that CXCL14/BRAK is a very promising molecular target for tumor suppression without side effects.

Journal Article

Animals, B16-F10-luc2, B16F10-luc2; Coloring Agents/administration & dosage/*diagnostic use; Indocyanine Green/administration & dosage/*diagnostic use; Injections, Intradermal; Liposomes/administration & dosage; Lymphatic Metastasis; Lymphatic Vessels/metabolism/*pathology; Melanoma, Experimental/blood supply/metabolism/*pathology; Mice; Mice, Inbred C57BL; Vascular Endothelial Growth Factor C/biosynthesis

Lymphatic vessels play a major role in cancer progression and in postsurgical lymphedema, and several new therapeutic approaches targeting lymphatics are currently being developed. Thus, there is a critical need for quantitative imaging methods to measure lymphatic flow. Indocyanine green (ICG) has been used for optical imaging of the lymphatic system, but it is unstable in solution and may rapidly enter venous capillaries after local injection. We developed a novel liposomal formulation of ICG (LP-ICG), resulting in vastly improved stability in solution and an increased fluorescence signal with a shift toward longer wavelength absorption and emission. When injected intradermally to mice, LP-ICG was specifically taken up by lymphatic vessels and allowed improved visualization of deep lymph nodes. In a genetic mouse model of lymphatic dysfunction, injection of LP-ICG showed no enhancement of draining lymph nodes and slower clearance from the injection site. In mice bearing B16 luciferase-expressing melanomas expressing vascular endothelial growth factor-C (VEGF-C), sequential near-IR imaging of intradermally injected LP-ICG enabled quantification of lymphatic flow. Increased flow through draining lymph nodes was observed in mice bearing VEGF-C-expressing tumors without metastases, whereas a decreased flow pattern was seen in mice with a higher lymph node tumor burden. This new method will likely facilitate quantitative studies of lymphatic function in preclinical investigations and may also have potential for imaging of lymphedema or improved sentinel lymph detection in cancer.

Journal Article

IntegriSense,, Animals; Diagnostic Imaging/*methods; Fluorescent Dyes/metabolism; Genes, Reporter; Neovascularization, Pathologic/*diagnosis; *Optical Phenomena

In recent years, molecular imaging gained significant importance in biomedical research. Optical imaging developed into a modality which enables the visualization and quantification of all kinds of cellular processes and cancerous cell growth in small animals. Novel gene reporter mice and cell lines and the development of targeted and cleavable fluorescent “smart” probes form a powerful imaging toolbox. The development of systems collecting tomographic bioluminescence and fluorescence data enabled even more spatial accuracy and more quantitative measurements. Here we describe various bioluminescent and fluorescent gene reporter models and probes that can be used to specifically image and quantify neovascularization or the angiogenic process itself.