Journal Article

Animals, B16-F10-luc2, B16F10-luc2; Antibodies, Monoclonal/diagnostic use/immunology; *Diagnostic Imaging; Female; Fluorodeoxyglucose F18/diagnostic use; Glycoproteins/*immunology; Humans; Inflammation/*complications/immunology/pathology; Iodine Radioisotopes/diagnostic use/pharmacokinetics; Luminescent Measurements; Lymph Nodes/immunology/pathology/*radionuclide imaging; *Lymphangiogenesis; Lymphatic Metastasis; Melanoma, Experimental/*complications/immunology/pathology; Mice; Mice, Inbred C57BL; Mice, Transgenic; *Positron-Emission Tomography; Prognosis; Radiopharmaceuticals/diagnostic use; Skin/metabolism; Tissue Distribution; Vascular Endothelial Growth Factor C/metabolism; Vascular Endothelial Growth Factor Receptor-3/immunology

Metastasis to regional lymph nodes (LN) is a prognostic indicator for cancer progression. There is a great demand for sensitive and noninvasive methods to detect metastasis to LNs. Whereas conventional in vivo imaging approaches have focused on the detection of cancer cells, lymphangiogenesis within tumor-draining LNs might be the earliest sign of metastasis. In mouse models of LN lymphangiogenesis, we found that systemically injected antibodies to lymphatic epitopes accumulated in the lymphatic vasculature in tissues and LNs. Using a (124)I-labeled antibody against the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), we imaged, for the first time, inflammation- and tumor-draining LNs with expanded lymphatic networks in vivo by positron emission tomography (PET). Anti-LYVE-1 immuno-PET enabled visualization of lymphatic vessel expansion in LNs bearing metastases that were not detected by [(18)F]fluorodeoxyglucose-PET, which is clinically applied to detect cancer metastases. Immuno-PET with lymphatic-specific antibodies may open up new avenues for the early detection of metastasis, and the images obtained might be used as biomarkers for the progression of diseases associated with lymphangiogenesis.

Journal Article

Animals, B16-F10-luc2, B16F10-luc2

Gene-directed enzyme prodrug therapy (GDEPT) has been investigated as a means of cancer treatment without affecting normal tissues. This system is based on the delivery of a suicide gene, a gene encoding an enzyme which is able to convert its substrate from non-toxic prodrug to cytotoxin. In this experiment, we have developed a targeted suicide gene therapeutic system that is completely contained within tumor-tropic cells and have tested this system for melanoma therapy in a preclinical model. First, we established double stable RAW264.7 monocyte/macrophage-like cells (Mo/Ma) containing a Tet-On(R) Advanced system for intracellular carboxylesterase (InCE) expression. Second, we loaded a prodrug into the delivery cells, double stable Mo/Ma. Third, we activated the enzyme system to convert the prodrug, irinotecan, to the cytotoxin, SN-38. Our double stable Mo/Ma homed to the lung melanomas after 1 day and successfully delivered the prodrug-activating enzyme/prodrug package to the tumors. We observed that our system significantly reduced tumor weights and numbers as targeted tumor therapy after activation of the InCE. Therefore, we propose that this system may be a useful targeted melanoma therapy system for pulmonary metastatic tumors with minimal side effects, particularly if it is combined with other treatments.

Journal Article

IVIS, 4T1-luc2

Heparan sulfate proteoglycans (HSPGs) play a key role in shaping the tumor microenvironment by presenting growth factors, cytokines, and other soluble factors that are critical for host cell recruitment and activation, as well as promoting tumor progression, metastasis, and survival. M402 is a rationally engineered, non-cytotoxic heparan sulfate (HS) mimetic, designed to inhibit multiple factors implicated in tumor-host cell interactions, including VEGF, FGF2, SDF-1alpha, P-selectin, and heparanase. A single s.c. dose of M402 effectively inhibited seeding of B16F10 murine melanoma cells to the lung in an experimental metastasis model. Fluorescent-labeled M402 demonstrated selective accumulation in the primary tumor. Immunohistological analyses of the primary tumor revealed a decrease in microvessel density in M402 treated animals, suggesting anti-angiogenesis to be one of the mechanisms involved in-vivo. M402 treatment also normalized circulating levels of myeloid derived suppressor cells in tumor bearing mice. Chronic administration of M402, alone or in combination with cisplatin or docetaxel, inhibited spontaneous metastasis and prolonged survival in an orthotopic 4T1 murine mammary carcinoma model. These data demonstrate that modulating HSPG biology represents a novel approach to target multiple factors involved in tumor progression and metastasis.

Journal Article

N/A

BACKGROUND: Lung cancer is the leading cause of cancer-related death in the United States, with more than half of the cancers are located peripherally. Computed tomography (CT) has been utilized in the last decade to detect early peripheral lung cancer. However, due to the high false diagnosis rate of CT, further biopsy is often necessary to confirm cancerous cases. This renders intervention for peripheral lung nodules (especially for small peripheral lung cancer) difficult and time-consuming, and it is highly desirable to develop new, on-the-spot earlier lung cancer diagnosis and treatment strategies. PURPOSE: The objective of this study is to develop a minimally invasive multimodality image-guided (MIMIG) intervention system to detect lesions, confirm small peripheral lung cancer, and potentially guide on-the-spot treatment at an early stage. Accurate image guidance and real-time optical imaging of nodules are thus the key techniques to be explored in this work. METHODS: The MIMIG system uses CT images and electromagnetic (EM) tracking to help interventional radiologists target the lesion efficiently. After targeting the lesion, a fiber-optic probe coupled with optical molecular imaging contrast agents is used to confirm the existence of cancerous tissues on-site at microscopic resolution. Using the software developed, pulmonary vessels, airways, and nodules can be segmented and visualized for surgical planning; the segmented results are then transformed onto the intra-procedural CT for interventional guidance using EM tracking. Endomicroscopy through a fiber-optic probe is then performed to visualize tumor tissues. Experiments using IntegriSense 680 fluorescent contrast agent labeling alphavbeta3 integrin were carried out for rabbit lung cancer models. Confirmed cancers could then be treated on-the-spot using radio-frequency ablation (RFA). RESULTS: The prototype system is evaluated using the rabbit VX2 lung cancer model to evaluate the targeting accuracy, guidance efficiency, and performance of molecular imaging. Using this system, we achieved an average targeting accuracy of 3.04 mm, and the IntegriSense signals within the VX2 tumors were found to be at least two-fold higher than those of normal tissues. The results demonstrate great potential for applying the system in human trials in the future if an optical molecular imaging agent is approved by the Food and Drug Administration (FDA). CONCLUSIONS: The MIMIG system was developed for on-the-spot interventional diagnosis of peripheral lung tumors by combining image-guidance and molecular imaging. The system can be potentially applied to human trials on diagnosing and treating earlier stage lung cancer. For current clinical applications, where a biopsy is unavoidable, the MIMIG system without contrast agents could be used for biopsy guidance to improve the accuracy and efficiency.

Journal Article

IntegriSense, Animals; Colorectal Neoplasms/*metabolism/*secondary; Disease Models, Animal; Image Processing, Computer-Assisted; Integrin alphaVbeta3/*metabolism; Intraoperative Period; Liver Neoplasms/*pathology; Male; Neoplasm Transplantation; Rats; Spectroscopy, Near-Infrared/*methods; Tumor Cells, Cultured

AIM: Near-infrared (NIR) fluorescence optical imaging is a promising technique to assess the extent of colorectal metastases during curative-intended surgery. However, NIR fluorescence imaging of liver metastases is highly challenging due to hepatic uptake and clearance of many fluorescent dyes. In the current study, the biodistribution and the ability to demarcate liver and peritoneal metastases were assessed during surgery in a syngeneic rat model of colorectal cancer using an integrin alpha(v)beta(3)-directed NIR fluorescence probe. METHODS: Liver tumors and peritoneal metastases were induced in 7 male WAG/Rij rats by subcapsular inoculation of 0.5 x 10(6) CC531 colorectal cancer rat cells into three distinct liver lobes. Intraoperative and ex vivo fluorescence measurements were performed 24 (N = 3 rats, 7 tumors) and 48 h (N = 4 rats, 9 tumors) after intravenous administration of the integrin alpha(v)beta(3)-directed NIR fluorescence probe. RESULTS: Colorectal metastases had a minimal two-fold higher NIR fluorescence signal than healthy liver tissue and other abdominal organs (p < 0.001). The tumor-to-background ratio was independent of time of imaging (24 h vs. 48 h post-injection; p = 0.31), which facilitates flexible operation planning in future clinical applications. Total fluorescence intensity was significantly correlated with the size of metastases (R(2) = 0.92 for the 24 h group, R(2) = 0.96 for the 48 h group). CONCLUSION: These results demonstrate that colorectal intra-abdominal metastases can be clearly demarcated during surgery using an integrin alpha(v)beta(3) targeting NIR fluorescence probe. Translating these findings to the clinic will have an excellent potential to substantially improve the quality of cancer surgery.