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Invadopodia Formation (invadopodia + formation)
Selected AbstractsInvolvement of Cdc42 and Rac small G proteins in invadopodia formation of RPMI7951 cellsGENES TO CELLS, Issue 12 2003Hirokazu Nakahara Background:, Invadopodia are membrane protrusions into the extracellular matrix by aggressive tumour cells. These structures are associated with sites of matrix degradation and invasiveness of malignant tumour cells in an in vitro fibronectin degradation/invasion assay. The Rho family small G proteins, consisting of the Rho, Rac and Cdc42 subfamilies, are implicated in various cell functions, such as cell shape change, adhesion, and motility, through reorganization of the actin cytoskeleton. We studied the roles of the Rho family small G proteins in invadopodia formation. Results:, We first demonstrated that invadopodia of RPMI7951 human melanoma cells extended into the matrix substratum on a vertical view using a laser scanning confocal microscope system. We confirmed that invadopodia were rich in actin filaments (F-actin) and visualized clearly with F-actin staining on a vertical view as well as on a horizontal view. We then studied the roles of Rho, Rac, and Cdc42 in invasiveness of the same cell line. In the in vitro fibronectin degradation/invasion assay, a dominant active mutant of Cdc42 enhanced dot-like degradation, whereas a dominant active mutant of Rac enhanced diffuse-type degradation. Furthermore, frabin, a GDP/GTP exchange protein for Cdc42 with F-actin-binding activity, enhanced both dot-like and diffuse-type degradation. However, a dominant active mutant of Rho did not affect the fibronectin degradation. Moreover, inhibition of phosphatidylinositol-3 kinase (PI3K) disrupted the Rac and Cdc42-dependent actin structures and blocked the fibronectin degradation. Conclusion:, These results suggest that Cdc42 and Rac play important roles in fibronectin degradation and invasiveness in a coordinate manner through the frabin-Cdc42/Rac-PI3K signalling pathway. [source] Transmembrane 4 L six family member 5 (TM4SF5) enhances migration and invasion of hepatocytes for effective metastasisJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2010Sin-Ae Lee Abstract Overexpression of transmembrane 4 L six family member 5 (TM4SF5), a four-transmembrane L6 family member, causes aberrant cell proliferation and angiogenesis, but the roles of TM4SF5 in migration, invasion, and tumor metastasis remain unknown. Using in vitro hepatocarcinoma cells that ectopically or endogenously express TM4SF5 and in vivo mouse systems, roles of TM4SF5 in metastatic potentials were examined. We found that TM4SF5 expression facilitated migration, invadopodia formation, MMP activation, invasion, and eventually lung metastasis in nude mice, but suppression of TM4SF5 with its shRNA blocked the effects. Altogether, TM4SF5-mediated migration and invasion suggest that TM4SF5 may be therapeutically targeted to deal with TM4SF5-mediated hepatocellular cancers. J. Cell. Biochem. 111: 59,66, 2010. © 2010 Wiley-Liss, Inc. [source] Role of MMP9 on invadopodia formation in cells from adenoid cystic carcinoma.MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2010Study by laser scanning confocal microscopy Abstract Migration, invasion and protease activity are essential for tumor progression and metastasis. Metastatic cells rely on invadopodia to degrade and invade extracellular matrix (ECM). Invadopodia are membrane protrusions with enzymes required for ECM degradation. These protrusions contain cortactin and membrane type 1 matrix metalloproteinase (MT1-MMP) superimposed to areas of digested matrix. Here we characterized invadopodia in a cell line (CAC2) derived from human adenoid cystic carcinoma. We carried out fluorescent-substrate degradation assay to assess in situ protease activity of CAC2 cells. Digestion spots in fluorescent substrate appear as black areas in green background. Cells were cultured on Matrigel-gelatin-FITC and fixed after 1 h and 3 h. CAC2 cells were double labeled to actin and cortactin. Cells were also double stained to actin and MT1-MMP. Samples were studied by laser scanning confocal microscopy. In all time points CAC2 cells showed actin, cortactin, and MT1-MMP colocalized with digestion spots in fluorescent substrate. We searched for other proteases involved in invadopodia activity. We have previously demonstrated that MMP9 influences adenoid cystic carcinoma behavior. This prompted us to investigate role played by MMP9 on invadopodia formation. CAC2 cells had MMP9 silenced by siRNA. After 1 h in fluorescent substrate, cells with silenced MMP9 showed clear decrease in matrix digestion compared with controls. No differences were found in cells with silenced MMP9 grown for 3 h on fluorescent substrate. Our results showed that CAC2 cells exhibit functional invadopodia containing cortactin and MT1-MMP. Furthermore, MMP9 would be required in the initial steps of invadopodia formation. Microsc. Res. Tech., 2010. © 2009 Wiley-Liss, Inc. [source] Phosphatidylinositol 4,5-bisphosphate and PIP5-kinase I, are required for invadopodia formation in human breast cancer cellsCANCER SCIENCE, Issue 7 2010Hideki Yamaguchi Invadopodia are ventral cell protrusions formed in invasive cancer cells. Because invadopodia have extracellular matrix (ECM) degradation activity, they are thought to function in cancer invasion. In this study, we examined the roles of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and PI(4,5)P2 -producing enzymes in invadopodia formation in MDA-MB-231 human breast cancer cells. Immunofluorescence analysis showed that PI(4,5)P2 accumulates at invadopodia on the ventral cell surface. Injection of an anti-PI(4,5)P2 antibody inhibited invadopodia formation along with gelatin degradation activity. Sequestering of PI(4,5)P2 by overexpression of the phospholipase C (PLC) ,1-pleckstrin homology (PH) domain, a specific probe for PI(4,5)P2, also blocked invadopodia formation, while a mutated PLC,1-PH domain that lacks PI(4,5)P2 -binding activity had no effect. Cellular PI(4,5)P2 production is mainly mediated by type-I phosphatidylinositol 4-phosphate 5-kinase (PIP5KI) family proteins, which include PIP5KI,, I,, and I,. Real-time quantitative PCR analysis showed that PIP5KI, is a dominant isoform expressed in MDA-MB-231 cells. Knockdown of PIP5KI, by small-interfering RNA (siRNA) inhibited invadopodia formation and gelatin degradation. Immunofluorescence analysis revealed that endogenous PIP5KI, protein localizes at invadopodia, which is corroborated by the observation that exogenously expressed green fluorescent protein (GFP)-fused PIP5KI, protein also accumulates at gelatin degradation sites. These results indicate that localized production of PI(4,5)P2 by PIP5KI, is required for invadopodia formation and ECM degradation by human breast cancer cells. (Cancer Sci 2010) [source] | |||||||||||||