Effective diagnosis of inflammation and cancer by molecular imaging is challenging because of interference from nonselective accumulation of the contrast agents in normal tissues. Here, we report a series of novel fluorescence imaging agents that efficiently target cyclooxygenase-2 (COX-2), which is normally absent from cells, but is found at high levels in inflammatory lesions and in many premalignant and malignant tumors. After either i.p. or i.v. injection, these reagents become highly enriched in inflamed or tumor tissue compared with normal tissue and this accumulation provides sufficient signal for in vivo fluorescence imaging. Further, we show that only the intact parent compound is found in the region of interest. COX-2-specific delivery was unambiguously confirmed using animals bearing targeted deletions of COX-2 and by blocking the COX-2 active site with high-affinity inhibitors in both in vitro and in vivo models. Because of their high specificity, contrast, and detectability, these fluorocoxibs are ideal candidates for detection of inflammatory lesions or early-stage COX-2-expressing human cancers, such as those in the esophagus, oropharynx, and colon.Cancer Res; 70(9); 3618-27. ©2010 AACR.

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming one of the most common forms of liver disease in Abstract The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. Recognition and timely diagnosis of these different stages, particularly NASH, is important for both potential reversibility and limitation of complications. Liver biopsy remains the clinical standard for defi nitive diagnosis. Diagnostic tools minimizing the need for invasive procedures or that add information to histologic data are important in novel management strategies for the growing epidemic of NAFLD. We describe an "omics" approach to detecting a reproducible signature of lipid metabolites, aqueous intracellular metabolites, SNPs, and mRNA transcripts in a double-blinded study of patients with different stages of NAFLD that involves profi ling liver biopsies, plasma, and urine samples. Using linear discriminant analysis, a panel of 20 plasma metabolites that includes glycerophospholipids, sphingolipids, sterols, and various aqueous small molecular weight components involved in cellular metabolic pathways, can be used to differentiate between NASH and steatosis. This identifi cation of differential biomolecular signatures has the potential to improve clinical diagnosis and facilitate therapeutic intervention of

G protein-coupled receptor ligand-dependent transactivation of growth factor receptors has been implicated in human cancer cell proliferation, migration, and cell survival. For example, prostaglandin E 2 (PGE2)-induced transactivation of the EGF receptor (EGFR) in colorectal carcinoma cells is mediated by means of a c-Src-dependent mechanism and regulates cell proliferation and migration. Recent evidence indicates that ␤-arrestin 1 may act as an important mediator in G protein-coupled receptor-induced activation of c-Src. Whether ␤-arrestin 1 serves a functional role in these events is, however, unknown. We investigated the effects of PGE 2 on colorectal cancer cells expressing WT and mutant ␤-arrestin 1. Here we report that PGE 2 induces the association of a prostaglandin E receptor 4͞␤-arrestin 1͞c-Src signaling complex resulting in the transactivation of the EGFR and downstream Akt (PKB) signaling. The interaction of ␤-arrestin 1 and c-Src is critical for the regulation of colorectal carcinoma cell migration in vitro as well as metastatic spread of disease to the liver in vivo. These results show that the prostaglandin E͞␤-arrestin 1͞c-Src signaling complex is a crucial step in PGE2-mediated transactivation of the EGFR and may play a pivotal role in tumor metastasis. Furthermore, our data implicate a functional role for ␤-arrestin 1 as a mediator of cellular migration and metastasis. metastasis ͉ prostaglandin E2 ͉ c-Src ͉ EGF receptor ͉ prostaglandin E receptor G protein-coupled receptors (GPCRs) comprise the largest known family of plasma membrane receptors and consist of a seven-transmembrane-spanning region f lanked by an extracellular N terminus and an intracellular C terminus. Upon ligand binding, these receptors couple to heterotrimeric G proteins (G␣-and G␤␥-subunits) and catalyze the exchange of GDP for GTP, thus initiating a multitude of signaling events into the cell. These include the classical activation of phosholipases (phosholipases A, C, and D), protein kinases (PKA and PKC), and lipid kinases (phosphatidylinositol 3-kinase) as well as increased intracellular calcium levels. The desensitization of GPCRs occurs through a multistep process. GPCR kinases are recruited to the receptor by liberated ␤␥-subunits and phosphorylate the receptor on the cytoplasmic tail and intracellular loops. This phosphorylation event triggers the association of arrestin, which then traffics the receptors to clathrin-coated pits for endocytosis (1).Prostaglandins (PG) are important bioactive lipids which exert their effects through the activation of specific GPCRs as well as members of the peroxisome proliferator-activated receptor family. For example, PGE 2 is the ligand for four prostaglandin E (EP) receptor isoforms termed EP1, EP2, EP3, and EP4. Stimulation of these receptors elicits different intracellular responses (2). The stimulation of the EP1 receptor induces an increase in intracellular calcium by means of the activation of phospholipase C. EP2 and EP4 receptors couple to G␣s proteins, which generate incre...

Background & Aims-Transforming growth factor (TGF)-β signaling occurs through Smads 2/3/4, which translocate to the nucleus to regulate transcription; TGF-β has tumor suppressive effects in some tumor models and pro-metastatic effects in others. In patients with colorectal cancer (CRC), mutations or reduced levels of Smad4 have been correlated with reduced survival. However, the function of Smad signaling and the effects of TGF-β receptor kinase inhibitors (TRKI) have not been analyzed during CRC metastasis. We investigated the role of TGF-β/Smad signaling in CRC progression.

Biliary cystadenoma must be recognized and treated differently than most hepatic cysts. There remains a need for education about the imaging findings for biliary cystadenoma to reduce the demonstrated delay in appropriate treatment. Traditional treatment of simple cysts such as aspiration, drainage, and marsupialization results in near universal recurrence and occasional malignant degeneration. This experience demonstrates effective options include total ablation by standard hepatic resection and cyst enucleation.

The role of specific stromal-derived matrix metalloproteinases (MMPs) was analyzed in experimental metastasis assays in wild-type and either MMP-9, MMP-7, or MMP-2 null mice. MMP-9 null mice showed an 81% reduction in Lewis lung carcinoma tumor number, whereas MMP-7 null mice showed a 42% increase in tumor number, and there was no difference in tumor number in MMP-2 null mice compared with wild-type controls. Similarly, in an orthotopic model of lung cancer, 50% fewer MMP-9 null mice were able to establish tumors in the lung compared with control mice, although the size of the tumors was not different. The effect of MMP-9 on lung tumor colonization was dependent on the expression of MMP-9 from bone marrow-derived cells and is most likely contributed by neutrophils. To examine temporal effects of stromal MMP-9, bioluminescence imaging from luciferase-expressing human lung cancer-derived A549 cells revealed that there were fewer tumor cells in the lungs of MMP-9 null mice as early as 19 hours after injection compared with control mice, with no difference in subsequent growth rates. Six hours after injection of tumor cells, MMP-9 null mice showed a 4-fold increase in the percent of tumor cells undergoing apoptosis compared with control mice. We conclude that MMP-9 from the bone marrow contributes to the early survival and establishment of tumors in the lung and has no effect on subsequent growth. These results provide insights into the failure of MMP inhibitors in clinical trials in patients with late-stage lung cancer. (Cancer Res 2006; 66(1): 259-66)

Non-alcoholic fatty liver disease (NAFLD), which includes steatosis and its progression to non-alcoholic steatohepatitis, is a liver disorder of increasing clinical significance. Here we characterize a murine model of high fat diet-induced NAFLD with progression from liver steatosis to histological features compatible with steatohepatitis and more advanced stages of NAFLD in humans, including chronic portal inflammation, pericellular and bridging fibrosis, Mallory body formation, and bile ductular reaction. Chronic changes induced by the prolonged consumption of a high-fat diet alone culminate in the development of primary liver dysplasias. Importantly, we extend these studies to demonstrate that even the early stages of uncomplicated steatosis provide a permissive microenvironment for the growth of colon cancer cells that are metastatic to the liver. High fat diet-induced steatosis, coupled with a splenic injection model of experimental liver metastasis using syngeneic MC38 colon cancer cells, resulted in an increased number of secondary tumor nodules and metastatic burden in steatotic livers. Metastatic nodules were associated with focal peritumoral areas of infiltrating inflammatory cells and associated apoptotic cell populations. These results suggest that the modulation of specific host factors in the steatotic liver contributes to tumor progression in the microenvironment of NAFLD.

Background and AimsThe spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and progression to cirrhosis. While differences in liver lipids between disease states have been reported, precise composition of phospholipids and diacylglycerols (DAG) at a lipid species level has not been previously described. The goal of this study was to characterize changes in lipid species through progression of human NAFLD using advanced lipidomic technology and compare this with a murine model of early and advanced NAFLD.MethodsUtilizing mass spectrometry lipidomics, over 250 phospholipid and diacylglycerol species (DAGs) were identified in normal and diseased human and murine liver extracts.ResultsSignificant differences between phospholipid composition of normal and diseased livers were demonstrated, notably among DAG species, consistent with previous reports that DAG transferases are involved in the progression of NAFLD and liver fibrosis. In addition, a novel phospholipid species (ether linked phosphatidylinositol) was identified in human cirrhotic liver extracts.ConclusionsUsing parallel lipidomics analysis of murine and human liver tissues it was determined that mice maintained on a high-fat diet provide a reproducible model of NAFLD in regards to specificity of lipid species in the liver. These studies demonstrated that novel lipid species may serve as markers of advanced liver disease and importantly, marked increases in DAG species are a hallmark of NAFLD. Elevated DAGs may contribute to altered triglyceride, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) levels characteristic of the disease and specific DAG species might be important lipid signaling molecules in the progression of NAFLD.