Citation Details

Journal Article

4T1-luc2, IVIS, Bioluminescence, Adenoviridae/genetics/*metabolism/physiology; Administration, Intravenous; Animals; Bone Neoplasms/secondary/*therapy; Cell Line, Tumor; Female; Humans; Immunocompetence; Luminescent Measurements/methods; Mammary Neoplasms, Experimental/pathology/*therapy; Mice; Mice, Inbred BALB C; Oncolytic Virotherapy/methods; Oncolytic Viruses/genetics/metabolism/physiology; Phosphorylation; Promoter Regions, Genetic; Protein-Serine-Threonine Kinases/genetics/*metabolism; Receptors, Transforming Growth Factor beta/genetics/*metabolism; Signal Transduction; Smad2 Protein/genetics/metabolism; Telomerase/genetics; Transforming Growth Factor beta1/genetics/metabolism; Transplantation, Isogeneic/methods; Tumor Stem Cell Assay/methods; Virus Replication

We have examined the effect of adenoviruses expressing soluble transforming growth factor receptorII-Fc (sTGFbetaRIIFc) in a 4T1 mouse mammary tumor bone metastasis model using syngeneic BALB/c mice. Infection of 4T1 cells with a non-replicating adenovirus, Ad(E1-).sTbetaRFc, or with two oncolytic adenoviruses, Ad.sTbetaRFc and TAd.sTbetaRFc, expressing sTGFbetaRIIFc (the human TERT promoter drives viral replication in TAd.sTbetaRFc) produced sTGFbetaRIIFc protein. Oncolytic adenoviruses produced viral replication and induced cytotoxicity in 4T1 cells. 4T1 cells were resistant to the cytotoxic effects of TGFbeta-1 (up to 10 ng ml(-1)). However, TGFbeta-1 induced the phosphorylation of SMAD2 and SMAD3, which were inhibited by co-incubation with sTGFbetaRIIFc protein. TGFbeta-1 also induced interleukin-11, a well-known osteolytic factor. Intracardiac injection of 4T1-luc2 cells produced bone metastases by day 4. Intravenous injection of Ad.sTbetaRFc (on days 5 and 7) followed by bioluminescence imaging (BLI) of mice on days 7, 11 and 14 in tumor-bearing mice indicated inhibition of bone metastasis progression (P<0.05). X-ray radiography of mice on day 14 showed a significant reduction of the lesion size by Ad.sTbetaRFc (P<0.01) and TAd.sTbetaRFc (P<0.05). Replication-deficient virus Ad(E1-).sTbetaRFc expressing sTGFbetaRIIFc showed some inhibition of bone metastasis, whereas Ad(E1-).Null was not effective in inhibiting bone metastases. Thus, systemic administration of Ad.sTbetaRFc and TAd.sTbetaRFc can inhibit bone metastasis in the 4T1 mouse mammary tumor model, and can be developed as potential anti-tumor agents for breast cancer.

Journal Article

OsteoSense

Preclinical models for musculoskeletal disorders are critical for understanding the pathogenesis of bone and joint disorders in humans and the development of effective therapies. The assessment of these models primarily relies on morphological analysis which remains time consuming and costly, requiring large numbers of animals to be tested through different stages of the disease. The implementation of preclinical imaging represents a keystone in the refinement of animal models allowing longitudinal studies and enabling a powerful, non-invasive and clinically translatable way for monitoring disease progression in real time. Our aim is to highlight examples that demonstrate the advantages and limitations of different imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and optical imaging. All of which are in current use in preclinical skeletal research. MRI can provide high resolution of soft tissue structures, but imaging requires comparatively long acquisition times; hence, animals require long-term anaesthesia. CT is extensively used in bone and joint disorders providing excellent spatial resolution and good contrast for bone imaging. Despite its excellent structural assessment of mineralized structures, CT does not provide in vivo functional information of ongoing biological processes. Nuclear medicine is a very promising tool for investigating functional and molecular processes in vivo with new tracers becoming available as biomarkers. The combined use of imaging modalities also holds significant potential for the assessment of disease pathogenesis in animal models of musculoskeletal disorders, minimising the use of conventional invasive methods and animal redundancy.

Journal Article

OsteoSense, Animals; Biopsy; Bone Remodeling; Bone and Bones/metabolism/pathology; Calcification, Physiologic; Cardiovascular Abnormalities/blood/complications/pathology/physiopathology; *Disease Progression; Female; Gene Expression Profiling; Gene Expression Regulation; Glycoproteins/metabolism; Humans; Kidney Failure, Chronic/blood/complications/pathology/physiopathology; Male; Mice; Mice, Inbred C57BL; Middle Aged; Mutation/genetics; Osteoclasts/metabolism/pathology; Osteocytes/*metabolism/*pathology; Protein-Serine-Threonine Kinases/genetics; Renal Osteodystrophy/blood/*metabolism/*pathology/physiopathology; Vascular Calcification; *Wnt Signaling Pathway/genetics

Chronic kidney disease-mineral bone disorder (CKD-MBD) is defined by abnormalities in mineral and hormone metabolism, bone histomorphometric changes, and/or the presence of soft-tissue calcification. Emerging evidence suggests that features of CKD-MBD may occur early in disease progression and are associated with changes in osteocyte function. To identify early changes in bone, we utilized the jck mouse, a genetic model of polycystic kidney disease that exhibits progressive renal disease. At 6 weeks of age, jck mice have normal renal function and no evidence of bone disease but exhibit continual decline in renal function and death by 20 weeks of age, when approximately 40% to 60% of them have vascular calcification. Temporal changes in serum parameters were identified in jck relative to wild-type mice from 6 through 18 weeks of age and were subsequently shown to largely mirror serum changes commonly associated with clinical CKD-MBD. Bone histomorphometry revealed progressive changes associated with increased osteoclast activity and elevated bone formation relative to wild-type mice. To capture the early molecular and cellular events in the progression of CKD-MBD we examined cell-specific pathways associated with bone remodeling at the protein and/or gene expression level. Importantly, a steady increase in the number of cells expressing phosphor-Ser33/37-beta-catenin was observed both in mouse and human bones. Overall repression of Wnt/beta-catenin signaling within osteocytes occurred in conjunction with increased expression of Wnt antagonists (SOST and sFRP4) and genes associated with osteoclast activity, including receptor activator of NF-kappaB ligand (RANKL). The resulting increase in the RANKL/osteoprotegerin (OPG) ratio correlated with increased osteoclast activity. In late-stage disease, an apparent repression of genes associated with osteoblast function was observed. These data confirm that jck mice develop progressive biochemical changes in CKD-MBD and suggest that repression of the Wnt/beta-catenin pathway is involved in the pathogenesis of renal osteodystrophy.

Journal Article

OsteoSense, Animals; Diagnostic Imaging; Disease Models, Animal; Fluorescence; *Kidney Pelvis; Mice; Ureteral Obstruction/*diagnosis

PURPOSE: Radiological imaging is the mainstay of diagnosing ureteropelvic junction obstruction. Current established radiological modalities can potentially differentiate the varying degrees of obstruction but they are limited in functionality, applicability and/or comprehensiveness. Of particular concern is that some tests require radiation, which has long-term consequences, especially in children. MATERIALS AND METHODS: We investigated the novel use of Genhance 680 dynamic fluorescence imaging to assess ureteropelvic junction obstruction in 20 mice that underwent partial or complete unilateral ureteral obstruction. Ultrasound, mercaptoacetyltriglycine renography, magnetic resonance imaging and fluorescence imaging were performed. RESULTS: Our model of partial and complete obstruction could be distinguished by ultrasound, mercaptoacetyltriglycine renography and magnetic resonance imaging, and was confirmed by histological analysis. Using fluorescence imaging distinct vascular and urinary parameters were identified in the partial and complete obstruction groups compared to controls. CONCLUSIONS: Fluorescence imaging is a feasible alternative radiological imaging modality to diagnose ureteropelvic junction obstruction. It provides continuous, detailed imaging without the risk of radiation exposure.

Journal Article

OsteoSense, Animals; Axis/chemistry/*metabolism/*pathology; *Calcification, Physiologic/genetics; Inflammation/genetics/metabolism/prevention & control; Mice; Mice, Transgenic; Molecular Imaging/*methods; Spondylitis, Ankylosing/diagnosis/*genetics/*metabolism; Time Factors

INTRODUCTION: The diagnosis of ankylosing spondylitis is made from a combination of clinical features and the presence of radiographic evidence that may be detected only after many years of inflammatory back pain. It is not uncommon to have a diagnosis confirmed 5 to 10 years after the initial onset of symptoms. Development of a more-sensitive molecular imaging technology to detect structural changes in the joints would lead to earlier diagnosis and quantitative tracking of ankylosis progression. Progressive ankylosis (ank/ank) mice have a loss of function in the Ank gene, which codes for a regulator of PPi transport. In this study, we used these ank/ank mutant mice to assess a noninvasive, quantitative measure of joint ankylosis with near-infrared (NIR) molecular imaging in vivo. METHODS: Three age groups (8, 12, and 18 weeks) of ank/ank (15 mice) and wild-type littermates (12 +/+ mice) were assessed histologically and radiographically. Before imaging, OsteoSense 750 (bisphosphonate pamidronate) was injected i.v. Whole-body images were analyzed by using the multispectral Maestro imaging system. RESULTS: OsteoSense 750 signals in the paw joints were higher in ank/ank mice in all three age groups compared with controls. In the spine, significantly higher OsteoSense 750 signals were detected early, in 8-week-old ank/ank mice compared with controls, although minimal radiographic differences were noted at this time point. The molecular imaging changes in the ank/ank spine (8 weeks) were supported by histologic changes, including calcium apatite crystals at the edge of the vertebral bodies and new syndesmophyte formation. CONCLUSIONS: Changes in joint pathology of ank/ank mice, as evaluated by histologic and radiographic means, are qualitative, but only semiquantitative. In contrast, molecular imaging provides a quantitative assessment. Ankylosis in ank/ank mice developed simultaneously in distal and axial joints, contrary to the previous notion that it is a centripetal process. NIR imaging might be feasible for early disease diagnosis and for monitoring disease progression in ankylosing spondylitis.