The metastatic process, i.e. the dissemination of cancer cells throughout the body to seed secondary tumors at distant sites, requires cancer cells to leave the primary tumor and to acquire migratory and invasive capabilities. In a process of epithelial-mesenchymal transition (EMT), besides changing their adhesive repertoire, cancer cells employ developmental processes to gain migratory and invasive properties that involve a dramatic reorganization of the actin cytoskeleton and the concomitant formation of membrane protrusions required for invasive growth. The molecular processes underlying such cellular changes are still only poorly understood, and the various migratory organelles, including lamellipodia, filopodia, invadopodia and podosomes, still require a better functional and molecular characterization. Notably, direct experimental evidence linking the formation of migratory membrane protrusions and the process of EMT and tumor metastasis is still lacking. In this review, we have summarized recent novel insights into the molecular processes and players underlying EMT on one side and the formation of invasive membrane protrusions on the other side.

In this review, we discuss the recent advances in green synthesis of silver nanoparticles, their application as antimicrobial agents and mechanism of antimicrobial mode of action.

Cell migration and invasion are critical parameters in the metastatic dissemination of cancer cells and the formation of metastasis, the major cause of death in cancer patients. Migratory cancer cells undergo dramatic molecular and cellular changes by remodeling their cell-cell and cell-matrix adhesion and their actin cytoskeleton, molecular processes that involve the activity of various signaling networks. Although in the past years, we have substantially expanded our knowledge on the cellular and molecular processes underlying cell migration and invasion in experimental systems, we still lack a clear understanding of how cancer cells disseminate in metastatic cancer patients. Different types of cancer cell migration seem to exist, including single-cell mesenchymal or amoeboid migration and collective cell migration. In most epithelial cancers, loss of the cell-cell adhesion molecule E-cadherin and gain of mesenchymal markers and promigratory signals underlie the conversion of epithelial, differentiated cells to mesenchymal, migratory, and invasive cells, a process referred to as the epithelial-to-mesenchymal transition. Although solitary migrating epithelial cancer cells have mostly undergone epithelial-to-mesenchymal transition (mesenchymal migration), and sometimes even lose their cell-matrix adhesion (amoeboid migration), collective migration of cancer cells in cell sheets, clusters, or streams is also frequently observed. The molecular mechanisms defining the different modes of cancer cell migration remain in most parts to be delineated. Mol Cancer Res; 8(5); 629-42. ©2010 AACR.Despite major efforts in metastasis research, we still lack detailed insights into how cancer cells actually migrate out of primary tumors and invade into neighboring tissue, how they enter (intravasate) into the blood or the lymphatic circulation, how they survive "homelessness" and immune surveillance in the bloodstream, and how they target certain organs to leave (extravasate) the blood circulation and to initiate metastatic outgrowth in specific target organs. Obviously, the migratory and invasive capabilities of a cancer cell present critical parameters in the metastatic cascade. Plenty of molecular pathways define distinct types of migration and invasion in a cancer cell-autonomous manner, including single-cell amoeboid and mesenchymal migration and collective cell migration (1, 2). In many instances, stromal cells, such as blood vessel and lymphatic endothelial cells, cancer-associated fibroblasts, or bone marrow-derived inflammatory cells, act as modulators of cancer cell migration and invasion and as pathfinders in the extracellular matrix (3). Moreover, chemokine gradients within the tumor microenvironment or in the blood and lymphatic system, as well as the establishment of an appropriate "metastatic niche" in future metastatic organs, contribute to the targeted colonization of distant organs (4). In this review, we present various concepts on the signaling pathways and molecular mechanisms underlying the onset of...

Obesity increases hepatocellular carcinoma (HCC) risks via unknown mediators. We report that hepatic unconventional prefoldin RPB5 interactor (URI) couples nutrient surpluses to inflammation and non-alcoholic steatohepatitis (NASH), a common cause of HCC. URI-induced DNA damage in hepatocytes triggers inflammation via T helper 17 (Th17) lymphocytes and interleukin 17A (IL-17A). This induces white adipose tissue neutrophil infiltration mediating insulin resistance (IR) and fatty acid release, stored in liver as triglycerides, causing NASH. NASH and subsequently HCC are prevented by pharmacological suppression of Th17 cell differentiation, IL-17A blocking antibodies, and genetic ablation of the IL-17A receptor in myeloid cells. Human hepatitis, fatty liver, and viral hepatitis-associated HCC exhibit increased IL-17A correlating positively with steatosis. IL-17A blockers may prevent IR, NASH, and HCC in high-risk patients.

Molecular mechanisms responsible for hepatocellular carcinoma (HCC) remain largely unknown. Using genetically engineered mouse models, we show that hepatocyte-specific expression of unconventional prefoldin RPB5 interactor (URI) leads to a multistep process of HCC development, whereas its genetic reduction in hepatocytes protects against diethylnitrosamine (DEN)-induced HCC. URI inhibits aryl hydrocarbon (AhR)- and estrogen receptor (ER)-mediated transcription of enzymes implicated in L-tryptophan/kynurenine/nicotinamide adenine dinucleotide (NAD(+)) metabolism, thereby causing DNA damage at early stages of tumorigenesis. Restoring NAD(+) pools with nicotinamide riboside (NR) prevents DNA damage and tumor formation. Consistently, URI expression in human HCC is associated with poor survival and correlates negatively with L-tryptophan catabolism pathway. Our results suggest that boosting NAD(+) can be prophylactic or therapeutic in HCC.