Journal Article

matrix metalloproteinase; neuroendocrine; prostate cancer; metatasis

Prostate cancer is the leading form of cancer in men. Prostate tumors often contain neuroendocrine differentiation, which correlates with androgen-independent progression and poor prognosis. Matrix metalloproteinases (MMP), a family of enzymes that remodel the microenvironment, are associated with tumorigenesis and metastasis. To evaluate MMPs during metastatic prostatic neuroendocrine cancer development, we used transgenic mice expressing SV40 large T antigen in their prostatic neuroendocrine cells, under the control of transcriptional regulatory elements from the mouse cryptdin-2 gene (CR2-TAg). These mice have a stereotypical pattern of tumorigenesis and metastasis. MMP-2, MMP-7, and MMP-9 activities increased concurrently with the transition to invasive metastatic carcinoma, but they were expressed in different prostatic cell types: stromal, luminal epithelium, and macrophages, respectively. CR2-TAg mice treated with AG3340/Prinomastat, an MMP inhibitor that blocks activity of MMP-2, MMP-9, MMP-13, and MMP-14, had reduced tumor burden. CR2-TAg animals were crossed to mice homozygous for null alleles of MMP-2, MMP-7, or MMP-9 genes. At 24 weeks CR2-TAg; MMP-2-/- mice showed reduced tumor burden, prolonged survival, decreased lung metastasis, and decreased blood vessel density, whereas deficiencies in MMP-7 or MMP-9 did not influence tumor growth or survival. Mice deficient for MMP-7 had reduced endothelial area coverage and decreased vessel size, and mice lacking MMP-9 had increased numbers of invasive foci and increased perivascular invasion, as well as decreased tumor blood vessel size. Together, these results suggest distinct contributions by MMPs to the progression of aggressive prostate tumor and to helping tumors cleverly find alternative routes to malignant progression.

Journal Article

brain tumor; glioma; human neural stem cells; TSP-1; endothelial cells; angiogenesis; in vivo imaging

Novel therapeutic agents combined with innovative modes of delivery and non-invasive imaging of drug delivery, pharmacokinetics and efficacy are crucial in developing effective clinical anticancer therapies. In this study, we have created and characterized multiple novel variants of anti-angiogenic protein thrombospondin (aaTSP-1) that comprises unique regions of three type-I-repeats of TSP-1 and used engineered human neural stem cells (hNSC) to provide sustained on-site delivery of secretable aaTSP-1 to tumor-vasculature. We show that hNSC-aaTSP-1 has anti-angiogenic effect on human brain and dermal microvascular endothelial cells co-cultured with established glioma cells and CD133+ glioma-initiating cells. Using human glioma cells and hNSC engineered with different combinations of fluorescent and bioluminescent marker proteins and employing multi-modality imaging techniques, we show that aaTSP-1 targets the vascular-component of gliomas and a single administration of hNSC-aaTSP-1 markedly reduces tumor vessel-density that results in inhibition of tumor-progression and increased survival in mice bearing highly malignant human gliomas. We also show that therapeutic hNSC do not proliferate and remain in an un-differentiated state in the brains of glioma-bearing mice. This study provides a platform for accelerated development of future cell-based therapies for cancer.

Journal Article

optical tomography; in vivo imaging; inflammation; Fluorescence molecular tomographic; FMT

Introduction: Standard measurements used to assess murine models of rheumatoid arthritis, notably paw thickness and clinical score, do not align well with certain aspects of disease severity as assessed by histopathology. We tested the hypothesis that non-invasive optical tomographic imaging of molecular biomarkers of inflammation and bone turnover would provide a superior quantitative readout and would discriminate between a disease-modifying anti-rheumatic drug (DMARD) and a non-DMARD treatment.

Methods: Using two protease-activated near-infrared fluorescence imaging agents to detect inflammation-associated cathepsin and matrix metalloprotease activity, and a third agent to detect bone turnover, we quantified fluorescence in paws of mice with collagen antibody-induced arthritis. Fluorescence molecular tomographic (FMT) imaging results, which provided deep tissue detection and quantitative readouts in absolute picomoles of agent fluorescence per paw, were compared with paw swelling, clinical scores, a panel of plasma biomarkers, and histopathology to discriminate between steroid (prednisolone), DMARD (p38 mitogen-activated protein kinase (MAPK) inhibitor) and non-DMARD (celecoxib, cyclooxygenase-2 (COX-2) inhibitor) treatments.

Results: Paw thickness, clinical score, and plasma biomarkers failed to discriminate well between a p38 MAPK inhibitor and a COX-2 inhibitor. In contrast, FMT quantification using near-infrared agents to detect protease activity or bone resorption yielded a clear discrimination between the different classes of therapeutics. FMT results agreed well with inflammation scores, and both imaging and histopathology provided clearer discrimination between treatments as compared with paw swelling, clinical score, and serum biomarker readouts.

Conclusions: Non-invasive optical tomographic imaging offers a unique approach to monitoring disease pathogenesis and correlates with histopathology assessment of joint inflammation and bone resorption. The specific use of optical tomography allowed accurate three-dimensional imaging, quantitation in picomoles rather than intensity or relative fluorescence, and, for the first time, showed that non-invasive imaging assessment can predict the pathologist's histology inflammation scoring and discriminate DMARD from non-DMARD activity.

Journal Article

FMT; bone; OsteoSense; FRFP; in vivo imaging

Bisphosphonate use has expanded beyond traditional applications to include treatment of a variety of low-bone-mass conditions. Complications associated with long-term bisphosphonate treatment have been noted, generating a critical need for information describing the local bisphosphonate-cell interactions responsible for these observations. This study demonstrates that a fluorescent bisphosphonate analogue, far-red fluorescent pamidronate (FRFP), is an accurate biomarker of bisphosphonate deposition and retention in vivo and can be used to monitor site-specific local drug concentration. In vitro, FRFP is competitively inhibited from the surface of homogenized rat cortical bone by traditional bisphosphonates. In vivo, FRFP delivery to the skeleton is rapid, with fluorescence linearly correlated with bone surface area. Limb fluorescence increases linearly with injected dose of FRFP; injected FRFP does not interfere with binding of standard bisphosphonates at the doses used in this study. Long-term FRFP retention studies demonstrated that FRFP fluorescence decreases in conditions of normal bone turnover, whereas fluorescence was retained in conditions of reduced bone turnover, demonstrating preservation of local FRFP concentration. In the mandible, FRFP localized to the alveolar bone and bone surrounding the periodontal ligament and molar roots, consistent with findings of osteonecrosis of the jaw. These findings support a role for FRFP as an effective in vivo marker for bisphosphonate site-specific deposition, turnover, and long-term retention in the skeleton.

Journal Article

aneurysm; imaging; vasculature; in vivo imaging; FMT; MMPSense

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