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

IntegriSense, Angiogenesis Inhibitors/therapeutic use; Animals; Diagnostic Imaging/*methods; Fluorescence; Humans; Luminescence/diagnostic use; Magnetic Resonance Angiography/methods; Magnetic Resonance Imaging/methods; Microscopy/methods; Neoplasms/*blood supply/therapy; *Neovascularization, Pathologic/pathology/ultrasonography; Positron-Emission Tomography/methods; Tomography/methods; Tomography, Emission-Computed, Single-Photon/methods; Tomography, X-Ray Computed/methods; X-Ray Microtomography/methods

Significant advances have been made in understanding the role of tumor angiogenesis and its influence on tumor progression in cancer. Based on this knowledge, a series of inhibitors of angiogenesis have been developed and evaluated in preclinical and clinical trials. Since detailed information of tumor progression in response to therapy is important to assess the efficacy of anti-tumor treatment in vivo, noninvasive imaging techniques emerge more and more as important tools to monitor alterations in tumor growth and vessel recruitment, as well as metastatic spread over time. So far, remarkable efforts have been made to improve the technical capability of these imaging modalities based on better resolution, as well as to implement multimodal approaches combining molecular with anatomical information. Advanced imaging techniques not only allow the detection and monitoring of tumor development, but also facilitate a broad understanding of the cellular and molecular events that propagate tumor angiogenesis, as well as those occurring in response to therapy. This review provides an overview of different imaging techniques in preclinical settings of oncological research and discusses their potential impact on clinical translation. Imaging modalities will be presented that have been implemented to address key biological issues by exploring tumor angiogenic processes and evaluating antiangiogenic therapy.

Journal Article

IVIS, Xenogen, Xen10

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Journal Article

Acetamides; Animals; Anti-Bacterial Agents; Bioware; Colony Count, Microbial; Daptomycin; Female; Luminescent Measurements; Methicillin Resistance; Mice; Microbial Sensitivity Tests; Neutropenia; Oxazolidinones; Peritonitis; Staphylococcus aureus; Xen29

The rising rates of antibiotic resistance accentuate the critical need for new antibiotics. Daptomycin is a new antibiotic with a unique mode of action and a rapid in vitro bactericidal effect against gram-positive organisms. This study examined the kinetics of daptomycin's bactericidal action against peritonitis caused by methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in healthy and neutropenic mice and compared this activity with those of other commonly used antibiotics. CD-1 mice were inoculated intraperitoneally with lethal doses of MSSA (Xen-29) or MRSA (Xen-1), laboratory strains transformed with a plasmid containing the lux operon, which confers bioluminescence. One hour later, the animals were given a single dose of daptomycin at 50 mg/kg of body weight subcutaneously (s.c.), nafcillin at 100 mg/kg s.c., vancomycin at 100 mg/kg s.c., linezolid at 100 mg/kg via gavage (orally), or saline (10 ml/kg s.c.). The mice were anesthetized hourly, and photon emissions from living bioluminescent bacteria were imaged and quantified. The luminescence in saline-treated control mice either increased (neutropenic mice) or remained relatively unchanged (healthy mice). In contrast, by 2 to 3 h postdosing, daptomycin effected a 90% reduction of luminescence of MSSA or MRSA in both healthy and neutropenic mice. The activity of daptomycin against both MSSA and MRSA strains was superior to those of nafcillin, vancomycin, and linezolid. Against MSSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than nafcillin or linezolid. Against MRSA peritonitis, daptomycin showed greater and more rapid bactericidal activity than vancomycin or linezolid. The rapid decrease in the luminescent signal in the daptomycin-treated neutropenic mice underscores the potency of this antibiotic against S. aureus in the immune-suppressed host.

Journal Article

IntegriSense, Animals; Antigens, Neoplasm/genetics/metabolism; Apoptosis; Blotting, Western; Cell Adhesion; Cell Adhesion Molecules/genetics/metabolism; Cell Differentiation; Cell Movement; Cell Proliferation; Cell Transformation, Neoplastic/metabolism/*pathology; Female; Flow Cytometry; Immunoenzyme Techniques; Mice; Mice, Inbred C57BL; Neoplastic Stem Cells/metabolism/*pathology; Ovarian Neoplasms/genetics/metabolism/*pathology; Ovary/metabolism/*pathology; Peritoneal Neoplasms/genetics/metabolism/*secondary; Proto-Oncogene Proteins c-myc/genetics/metabolism; Proto-Oncogene Proteins p21(ras)/genetics/metabolism; RNA, Messenger/genetics; RNA, Small Interfering/genetics; Reverse Transcriptase Polymerase Chain Reaction; Tumor Suppressor Protein p53/antagonists & inhibitors/genetics/*metabolism

Although the existence of tumor-initiating cells (T-ICs) in several types of human cancer has been documented, the contribution of somatic stem cells to the development of T-ICs has remained unclear. Here, we show that normal mouse ovary contains epithelial cell adhesion molecule (EpCAM)-expressing stem-like cells that possess the ability to differentiate into cytokeratin 8 (CK8)-expressing epithelial progeny cells. Furthermore, RNA interference-mediated transient depletion of the tumor suppressor p53 followed by retrovirus-mediated transfer of c-Myc and K-Ras oncogenes in EpCAM-expressing ovarian stem-like cells resulted in the generation of ovarian T-ICs. The established ovarian T-ICs gave rise to hierarchically organized lethal tumors in vivo and were able to undergo peritoneal metastasis. Finally, subsequent RNA interference-mediated knockdown of p53 in tumor cells triggered the expansion of EpCAM-expressing stem-like tumor cells and induced further tumor growth. These data reveal a role for p53 in the development and expansion of ovarian stem-like tumor cells and subsequent malignant progression.