Metastasis-associated gene expression profile of liver and subcutaneous lesions derived from mouse pheochromocytoma cells.

The development of metastatic cancer is associated with overexpression or downregulation of specific genes and cell regulatory pathways. Some of these genes and pathways may be involved in invasion and dissemination of tumor cells, while others may promote seeding, survival or growth of cells at specific distant sites. In this investigation, gene expression profiles of nonmetastasizing tumors generated by injecting mouse pheochromocytoma cells (MPCs) subcutaneously were compared to those of liver tumors generated by injecting the cells intravenously. Both were compared to the cultured parental cell line. Tumors in the liver have a route of spread, anatomical distribution, and growth environment similar to naturally metastasizing pheochromocytomas, while intravenous injection of cells bypasses the initial steps of metastasis occurring spontaneously from a primary tumor. Eight genes were upregulated in liver tumors, 15 in subcutaneous tumors and seven in both compared to the cultured cells. Using quantitative real-time PCR, expression of five genes (Metap2, Reck, S100a4, Timp2, and Timp3) was verified as significantly lower in liver tumors than in subcutaneous tumors. Downregulation of these genes has been previously been associated with malignancy of pheochromocytomas. These findings indicate that different microenvironments can differentially affect the expression of metastasis-related genes in pheochromocytomas, and that overexpression or underexpression of these genes need not be present when the tumor cells are initially disseminated. The hepatic localization of tumors formed by intravenously injected MPC cells and the tumors' gene expression profile resembling that of naturally occurring pheochromocytoma metastases support the use of this model to study pheochromocytoma metastasis.

Simvastatin promotes cell metabolism, proliferation, and osteoblastic differentiation in human periodontal ligament cells.

BACKGROUND: Simvastatin is one of the cholesterol lowering drugs. Recent studies demonstrated that it has a bone stimulatory effect. Periodontal ligament (PDL) cells are believed to play an important role in periodontal regeneration; that is, they may differentiate into specific cells which make cementum, bone, and attachment apparatus. It would be of interest whether simvastatin has a positive effect on PDL cells. Therefore, effects of simvastatin on cell proliferation and osteoblastic differentiation in PDL cells were analyzed. METHODS: Human PDL cells were cultured in monolayer with simvastatin for 24 and 72 hours and cell metabolism and proliferation were determined. To analyze osteoblastic differentiation, human PDL cells were cultured in organoid culture for 7, 14, and 21 days and alkaline phosphatase (ALP) activity, osteopontin (OPN), bone morphogenetic protein (BMP) -2, osteocalcin (OCN), and calcium contents were measured. They were co-treated by simvastatin and mevalonate. RESULTS: Simvastatin enhanced cell proliferation and metabolism dose-dependently after 24 hours. Simvastatin also stimulated ALP activity of human PDL cells dose-dependently, and maximum effect was obtained at the concentration of 10(8) M. In time dependent analysis, 10(8) M simvastatin stimulated ALP activity and osteopontin content after 7 days and calcium contents after 21 days. BMP-2 and OCN contents were not detected. Moreover this statin-enhanced ALP activity was abolished by mevalonate. CONCLUSION: These results suggest that at low concentration, simvastatin exhibits positive effect on proliferation and osteoblastic differentiation of human PDL cells, and these effects may be caused by the inhibition of the mevalonate pathway.

Potential role of the formyl peptide receptor-like 1 (FPRL1) in inflammatory aspects of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive, neurodegenerative disease characterized by the presence of multiple senile plaques in the brain tissue, which are also associated with considerable inflammatory infiltrates. Although the precise mechanisms of the pathogenesis of AD remain to be determined, the overproduction and precipitation of a 42 amino acid form of beta amyloid (Abeta(42)) in plaques have implicated Abeta in neurodegeneration and proinflammatory responses seen in the AD brain. Our recent studies revealed that the activation of formyl peptide receptor-like 1 (FPRL1), a seven-transmembrane, G-protein-coupled receptor, by Abeta(42) may be responsible for accumulation and activation of mononuclear phagocytes (monocytes and microglia). We further found that upon binding FPRL1, Abeta(42) was rapidly internalized into the cytoplasmic compartment in the form of Abeta(42)/FPRL1 complexes. Persistent exposure of FPRL1-expressing cells to Abeta(42) resulted in intracellular retention of Abeta(42)/FPRL1 complexes and the formation of Congo-red-positive fibrils in mononuclear phagocytes. Our observations suggest that FPRL1 may not only mediate the proinflammatory activity of Abeta(42) but also actively participate in Abeta(42) uptake and the resultant fibrillar formation. Therefore, FPRL1 may constitute an additional molecular target for the development of therapeutic agents for AD.

Receptors for chemotactic formyl peptides as pharmacological targets.

Leukocytes accumulate at sites of inflammation and immunological reaction in response to locally existing chemotactic mediators. N-formyl peptides, such as fMet-Leu-Phe (fMLF), are some of the first identified and most potent chemoattractants for phagocytic leukocytes. In addition to the bacterial peptide fMLF and the putative endogenously produced formylated peptides, a number of novel peptide agonists have recently been identified that selectively activate the high-affinity fMLF receptor FPR and/or its low-affinity variant FPRL1, both of which belong to the seven-transmembrane (STM), G protein-coupled receptor (GPCR) superfamily. These agonists include peptide domains derived from the envelope proteins of human immunodeficiency virus type 1 (HIV-1) and at least three amyloidogenic polypeptides, the human acute phase protein serum amyloid A, the 42 amino acid form of beta amyloid peptide and a 21 amino acid fragment of human prion. Furthermore, a cleavage fragment of neutrophil granule-derived bactericidal cathelicidin, LL-37, is also a chemotactic agonist for FPRL1. Activation of formyl peptide receptors results in increased cell migration, phagocytosis, release of proinflammatory mediators, and the signaling cascade culminates in heterologous desensitization of other STM receptors including chemokine receptors CCR5 and CXCR4, two coreceptors for HIV-1. Thus, by interacting with a variety of exogenous and host-derived agonists, formyl peptide receptors may play important roles in proinflammatory and immunological diseases and constitute a novel group of pharmacological targets.