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Molecular and Cellular Biology Jun 2009The tumor-suppressive role of p53 at the level of tumor initiation is well documented. It has also been shown previously that p53 acts against tumor...
The tumor-suppressive role of p53 at the level of tumor initiation is well documented. It has also been shown previously that p53 acts against tumor progression/metastasis. However, its role in modulating cell migration and invasion leading to metastasis is poorly understood. In this study, using vascular smooth muscle cells and NIH 3T3 fibroblast cells, we have shown that p53 potently suppresses Src-induced podosome/rosette formation, extracellular matrix digestion, cell migration, and invasion. The overexpression of exogenous wild-type p53 or the activation of the endogenous p53 function suppresses, while the short hairpin RNA-mediated knockdown of p53 expression or the pageing of its function exacerbates, Src-induced migratory and invasive phenotypes. We have also found that p53 expression and function are downregulated in cells stably transformed with constitutively active Src that exhibit aggressive invasive properties. Lastly, p53 upregulates the expression of caldesmon, an actin-binding protein that has been shown to be an inhibitor of podosome/invadopodium formation. The ability of p53 to suppress Src phenotypes in transformed cells was largely abolished by knocking down caldesmon. This study reports a novel molecular mechanism (caldesmon), as well as a structural basis (podosomes/rosettes), to show how p53 can act as an anti-motility/invasion/metastasis agent.
Topics: Animals; Blood Vessels; Calmodulin-Binding Proteins; Cell Movement; Collagen; Drug Combinations; Enzyme Activation; Extracellular Matrix; Laminin; Mice; Microfilament Proteins; Models, Biological; Myocytes, Smooth Muscle; NIH 3T3 Cells; Proteoglycans; Proto-Oncogene Proteins pp60(c-src); Pseudopodia; Rats; Tetradecanoylphorbol Acetate; Tumor Suppressor Protein p53; Up-Regulation
PubMed: 19349302
DOI: 10.1128/MCB.01816-08 -
The Journal of Cell Biology Feb 2020Podosomes are compartmentalized actin-rich adhesions, defined by their ability to locally secrete proteases and remodel extracellular matrix. Matrix remodeling by...
Podosomes are compartmentalized actin-rich adhesions, defined by their ability to locally secrete proteases and remodel extracellular matrix. Matrix remodeling by endothelial podosomes facilitates invasion and thereby vessel formation. However, the mechanisms underlying endothelial podosome formation and function remain unclear. Here, we demonstrate that Septin2, Septin6, and Septin7 are required for maturation of nascent endothelial podosomes into matrix-degrading organelles. We show that podosome development occurs through initial mobilization of the scaffolding protein Tks5 and F-actin accumulation, followed by later recruitment of Septin2. Septin2 localizes around the perimeter of podosomes in close proximity to the basolateral plasma membrane, and phosphoinositide-binding residues of Septin2 are required for podosome function. Combined, our results suggest that the septin cytoskeleton forms a diffusive barrier around nascent podosomes to promote their maturation. Finally, we show that Septin2-mediated regulation of podosomes is critical for endothelial cell invasion associated with angiogenesis. Therefore, targeting of Septin2-mediated podosome formation is a potentially attractive anti-angiogenesis strategy.
Topics: Actin Cytoskeleton; Adaptor Proteins, Vesicular Transport; Animals; Cell Cycle Proteins; Cell Movement; Cells, Cultured; Endothelial Cells; Extracellular Matrix; Humans; Morphogenesis; Neovascularization, Physiologic; Podosomes; Septins
PubMed: 31865373
DOI: 10.1083/jcb.201903023 -
Journal of Cardiobiology May 2017The purpose of the study was to localize matrix metalloproteinase (MMP)-14, -9, and -2 in the A7r5 smooth muscle cell and to understand the interaction between these...
AIM
The purpose of the study was to localize matrix metalloproteinase (MMP)-14, -9, and -2 in the A7r5 smooth muscle cell and to understand the interaction between these MMPs and the cytoskeleton. This interaction was observed under non-stimulating and phorbol 12, 13-dibutyrate (PDBu)-stimulating conditions.
METHODS
Confocal microscopy was utilized to define the localizations of MMPs and tissue inhibitor of matrix metalloproteinases (TIMPs) in the A7r5 cell and to determine interaction between MMPs and the cytoskeleton. Under PDBu-stimulating conditions, the presence of MMP active forms and activity by gel zymography was evaluated in the A7r5 cell. Actin and microtubule-polymerization inhibitors were used to evaluate MMP interaction with the cytoskeleton and the cytoskeleton was observed on matrix and within a Type I collagen gel.
RESULTS
MMP-14, -9, and -2 were localized to the podosome in the A7r5 smooth muscle cell and interactions were seen with these MMPs and the actin cytoskeleton. PDBu-stimulation induced increases in the protein abundance of the active forms of the MMPs and MMP-2 activity was increased. MMPs also interact with a-actin and not β-tubulin in the A7r5 cell. Galardin, also known as GM-6001, was shown to inhibit podosome formation and prevented MMP localization to the podosome. This broad spectrum MMP inhibitor also prevented collagen gel contraction and prevented cell adhesion and spreading of A7r5 cells within this collagen matrix.
CONCLUSION
MMPs are important in the formation and function of podosomes in the A7r5 smooth muscle cell. MMPs interact with a-actin and not β-tubulin in the A7r5 cell. Podosomes play an important role in cell migration and understanding the function of podosomes can lead to insights into cancer metastasis and cardiovascular disease.
PubMed: 30931350
DOI: 10.13188/2332-3671.1000020 -
Nature Communications Nov 2019Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and...
Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and podosomes. An adequate structural framework for this process is still missing. Here, we reveal the modular actin nano-architecture that enables podosome protrusion and mechanosensing. The podosome protrusive core contains a central branched actin module encased by a linear actin module, each harboring specific actin interactors and actin isoforms. From the core, two actin modules radiate: ventral filaments bound by vinculin and connected to the plasma membrane and dorsal interpodosomal filaments crosslinked by myosin IIA. On stiff substrates, the actin modules mediate long-range substrate exploration, associated with degradative behavior. On compliant substrates, the vinculin-bound ventral actin filaments shorten, resulting in short-range connectivity and a focally protrusive, non-degradative state. Our findings redefine podosome nanoscale architecture and reveal a paradigm for how actin modularity drives invadosome mechanosensing in cells that breach tissue boundaries.
Topics: Actins; Animals; Cell Adhesion; Cell Membrane; Cell Movement; Cells, Cultured; Dendritic Cells; Humans; Mechanotransduction, Cellular; Mice; Podosomes
PubMed: 31729386
DOI: 10.1038/s41467-019-13123-3 -
Journal of Virology Apr 2021Macrophages are one of the major targets of (HIV-1) and play crucial roles in viral dissemination and persistence during AIDS progression. Here, we reveal the dynamic...
Macrophages are one of the major targets of (HIV-1) and play crucial roles in viral dissemination and persistence during AIDS progression. Here, we reveal the dynamic podosome-mediated entry of HIV-1 into macrophages. Inhibition of podosomes prevented HIV-1 entry into macrophages, while stimulation of podosome formation promoted viral entry. Single-virus tracking revealed the temporal and spatial mechanism of the dynamic podosome-mediated viral entry process. The core and ring structures of podosomes played complex roles in viral entry. The HIV coreceptor, CCR5, was recruited to form specific clusters at the podosome ring, where it participated in viral entry. The podosome facilitated HIV-1 entry with a rotation mode triggered by dynamic actin. Our discovery of this novel HIV-1 entry route into macrophages, mediated by podosomes critical for cell migration and tissue infiltration, provides a new view of HIV infection and pathogenesis, which may assist in the development of new antiviral strategies.Macrophages are motile leukocytes and play critical roles in HIV-1 infection and AIDS progression. Podosomes, as small dynamic adhesion microdomains driven by the dynamic actin cytoskeleton, are mainly involved in cell migration of macrophages. Herein, we found that HIV-1 uses dynamic podosomes to facilitate its entry into macrophages. Single-virus imaging coupled with drug assays revealed the mechanism underlying the podosome-mediated route of HIV-1 entry into macrophages, including the dynamic relationship between the viral particles and the podosome core and ring structures, the CCR5 coreceptor. The dynamic podosome-mediated entry of HIV-1 into macrophages will be very significant for HIV-1 pathogenesis, especially for viral dissemination via macrophage migration and tissue infiltration. Thus, we report a novel HIV-1 entry route into macrophages mediated by podosomes, which extends our understanding of HIV infection and pathogenesis.
PubMed: 33627394
DOI: 10.1128/JVI.02480-20 -
Cancer Letters Feb 2024Growing evidence has suggested that increased matrix stiffness can significantly strengthen the malignant characteristics of hepatocellular carcinoma (HCC) cells....
Growing evidence has suggested that increased matrix stiffness can significantly strengthen the malignant characteristics of hepatocellular carcinoma (HCC) cells. However, whether and how increased matrix stiffness regulates the formation of invadopodia in HCC cells remain largely unknown. In the study, we developed different experimental systems in vitro and in vivo to explore the effects of matrix stiffness on the formation of invadopodia and its relevant molecular mechanism. Our results demonstrated that increased matrix stiffness remarkably augmented the migration and invasion abilities of HCC cells, upregulated the expressions of invadopodia-associated genes and enhanced the number of invadopodia. Two regulatory pathways contribute to matrix stiffness-driven invadopodia formation together in HCC cells, including direct triggering invadopodia formation through activating integrin β1 or Piezo1/ FAK/Src/Arg/cortactin pathway, and indirect stimulating invadopodia formation through improving EGF production to activate EGFR/Src/Arg/cortactin pathway. Src was identified as the common hub molecule of two synergistic regulatory pathways. Simultaneously, activation of integrin β1/RhoA/ROCK1/MLC2 and Piezo1/Ca/MLCK/MLC2 pathways mediate matrix stiffness-reinforced cell migration. This study uncovers a new mechanism by which mechanosensory pathway and biochemical signal pathway synergistically regulate the formation of invadopodia in HCC cells.
Topics: Humans; Carcinoma, Hepatocellular; Cortactin; Podosomes; Liver Neoplasms; Integrin beta1; Extracellular Matrix; Cell Line, Tumor; Neoplasm Invasiveness; rho-Associated Kinases
PubMed: 38145655
DOI: 10.1016/j.canlet.2023.216597 -
Arteriosclerosis, Thrombosis, and... Feb 2009We and others showed that tyrosine kinase receptors (TKRs) such as the epidermal growth factor receptor stimulate G protein-coupled receptor (GPCR) kinase-interacting...
OBJECTIVE
We and others showed that tyrosine kinase receptors (TKRs) such as the epidermal growth factor receptor stimulate G protein-coupled receptor (GPCR) kinase-interacting protein 1 (GIT1) phosphorylation via c-Src, which is required for phospholipase C-gamma (PLCgamma) activation, indicating that GIT1 participates in TKR signaling. VEGF is the most important TKR in endothelial cells (ECs); essential for cell survival, migration, and angiogenesis. Podosomes, actin-rich structures, were found to contribute to EC migration, tissue invasion, and matrix remodeling, suggesting a role for podosomes in angiogenesis. Because GIT1 is a substrate of c-Src, and podosome formation is c-Src dependent, we hypothesized that GIT1 plays an important role in VEGF-induced EC podosome formation and cell migration.
METHODS AND RESULTS
Exposure of ECs to VEGF for 30 minutes stimulated GIT1 colocalization with podosomes. Depletion of GIT1 by siRNA significantly decreased VEGF-induced podosome formation. A key role for PLCgamma was suggested by several experiments. Double staining PLCgamma and actin showed colocalization of PLCgamma with podosomes. Podosome formation was dramatically reduced by PLCgamma inhibitor U73122, Src inhibitor PP2, or expression of dominant negative small GTPases. Therefore, VEGF-induced EC podosome formation is dependent on Src, GIT1, PLCgamma, and small GTPases. In addition, matrix metalloprotease 2 (MMP2) and MT-MMP1 were detected at sites of VEGF-induced podosomes. Depletion of GIT1 by siRNA also significantly inhibited VEGF-induced MMP2 activation and extracellular matrix (ECM) degradation. Therefore, GIT1 mediates VEGF-induced matrix metalloproteinase (MMP) activation and ECM degradation by regulating podosome formation. Finally, depletion of GIT1 by siRNA significantly decreased VEGF-induced cell migration.
CONCLUSIONS
These data indicate that GIT1 is an essential mediator for VEGF-induced EC podosome formation and cell migration via PLCgamma.
Topics: Adaptor Proteins, Signal Transducing; Cell Cycle Proteins; Cell Movement; Cell Surface Extensions; Cells, Cultured; Endothelial Cells; Enzyme Inhibitors; Extracellular Matrix; Humans; Matrix Metalloproteinase 14; Matrix Metalloproteinase 2; Monomeric GTP-Binding Proteins; Phospholipase C gamma; RNA Interference; RNA, Small Interfering; Signal Transduction; Transfection; Vascular Endothelial Growth Factor A
PubMed: 19023093
DOI: 10.1161/ATVBAHA.108.174391 -
Small GTPases Sep 2018Metastatization is a complex multistep process requiring fine-tuned regulated cytoskeleton re-modeling, mediated by the cross-talk of actin with interacting partners,... (Review)
Review
Metastatization is a complex multistep process requiring fine-tuned regulated cytoskeleton re-modeling, mediated by the cross-talk of actin with interacting partners, such as the Rho GTPases. Our expanding knowledge of invadopodia, small invasive membrane protrusions composed of a core of F-actin, actin regulators and actin-binding proteins, and hotspots for secretion of extracellular matrix (ECM) proteinases, contributes to clarify critical steps of the metastatic program. Growth factor receptors and their intermediate signaling molecules, along with matrix adhesion and rigidity, pH and hypoxia, act as drivers of cytoskeleton changes and invadopodia formation. We recently pro-posed a novel route map by which cancer cells regulates invadopodia dynamics supporting metastasis as response to the endothelin A receptor (ETR), among the highly druggable G-protein coupled receptors in cancer. The metastatic behavior exhibited by ovarian cancer cells overe-xpressing ETR is now explained by the interplay with β-arrestin1 (β-arr1), a scaffold protein acting as signal-integrating module of RhoC and cofilin signaling for specific invadopodia formation, accomplished by its interaction with a Rho guanine nucleotide exchange factor (GEF), PDZ-RhoGEF, in a G-protein independent manner. Here, we summarize this novel activation of the RhoC pathway from ETR/β-arr1 signaling that may be exploited therapeutically and discuss new perspectives for future directions of investigations.
Topics: Humans; Podosomes; Receptor, Endothelin A; beta-Arrestin 1
PubMed: 27690729
DOI: 10.1080/21541248.2016.1235526 -
Journal of Cell Science May 2023Rac (herein referring to the Rac family) and Cdc42 are Rho GTPases that regulate the formation of lamellipoda and filopodia, and are therefore crucial in processes such...
Rac (herein referring to the Rac family) and Cdc42 are Rho GTPases that regulate the formation of lamellipoda and filopodia, and are therefore crucial in processes such as cell migration. Relocation-based biosensors for Rac and Cdc42 have not been characterized well in terms of their specificity or affinity. In this study, we identify relocation sensor candidates for both Rac and Cdc42. We compared their (1) ability to bind the constitutively active Rho GTPases, (2) specificity for Rac and Cdc42, and (3) relocation efficiency in cell-based assays. Subsequently, the relocation efficiency was improved by a multi-domain approach. For Rac1, we found a sensor candidate with low relocation efficiency. For Cdc42, we found several sensors with sufficient relocation efficiency and specificity. These optimized sensors enable the wider application of Rho GTPase relocation sensors, which was showcased by the detection of local endogenous Cdc42 activity at assembling invadopodia. Moreover, we tested several fluorescent proteins and HaloTag for their influence on the recruitment efficiency of the Rho location sensor, to find optimal conditions for a multiplexing experiment. This characterization and optimization of relocation sensors will broaden their application and acceptance.
Topics: rho GTP-Binding Proteins; Cell Movement; Podosomes; Pseudopodia
PubMed: 37226883
DOI: 10.1242/jcs.260802 -
Cell Reports Oct 2023During metastasis, tumor cells invade through the basement membrane and intravasate into blood vessels and then extravasate into distant organs to establish metastases....
During metastasis, tumor cells invade through the basement membrane and intravasate into blood vessels and then extravasate into distant organs to establish metastases. Here, we report a critical role of a transmembrane serine protease fibroblast activation protein (FAP) in tumor metastasis. Expression of FAP and TWIST1, a metastasis driver, is significantly correlated in several types of human carcinomas, and FAP is required for TWIST1-induced breast cancer metastasis to the lung. Mechanistically, FAP is localized at invadopodia and required for invadopodia-mediated extracellular matrix degradation independent of its proteolytic activity. Live cell imaging shows that association of invadopodia precursors with FAP at the cell membrane promotes the stabilization and growth of invadopodia precursors into mature invadopodia. Together, our study identified FAP as a functional target of TWIST1 in driving tumor metastasis via promoting invadopodia-mediated matrix degradation and uncovered a proteolytic activity-independent role of FAP in stabilizing invadopodia precursors for maturation.
Topics: Humans; Female; Podosomes; Cell Line, Tumor; Peptide Hydrolases; Neoplasm Invasiveness; Breast Neoplasms; Membrane Proteins; Serine Endopeptidases; Fibroblasts; Extracellular Matrix; Melanoma, Cutaneous Malignant
PubMed: 37862167
DOI: 10.1016/j.celrep.2023.113302