MT1-MMP (MMP-14) is a multifunctional protease that regulates ECM degradation, activation of other proteases, and a variety of cellular processes, including migration and viability in physiological and pathological contexts. Both the localization and signal transduction capabilities of MT1-MMP are dependent on its cytoplasmic domain that constitutes the final 20 C-terminal amino acids, while the rest of the protease is extracellular. In this review, we summarize the ways in which the cytoplasmic tail is involved in regulating and enacting the functions of MT1-MMP. We also provide an overview of known interactors of the MT1-MMP cytoplasmic tail and the functional significance of these interactions, as well as further insight into the mechanisms of cellular adhesion and invasion that are regulated by the cytoplasmic tail.

• Keywords
• MT1-MMP, cell invasion, intracellular trafficking, matrix metalloproteinases, post-translational modifications,
• MeSH
• Cell Adhesion MeSH
• Matrix Metalloproteinase 14 * metabolism   MeSH
• Cell Movement MeSH
• Signal Transduction * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Matrix Metalloproteinase 14 * MeSH

Sarcomas are a heterogeneous group of mesenchymal tumours, with a great variability in their clinical behaviour. While our knowledge of sarcoma initiation has advanced rapidly in recent years, relatively little is known about mechanisms of sarcoma progression. JUN-murine fibrosarcoma progression series consists of four sarcoma cell lines, JUN-1, JUN-2, JUN-2fos-3, and JUN-3. JUN-1 and -2 were established from a single tumour initiated in a H2K/v-jun transgenic mouse, JUN-3 originates from a different tumour in the same animal, and JUN-2fos-3 results from a targeted in vitro transformation of the JUN-2 cell line. The JUN-1, -2, and -3 cell lines represent a linear progression from the least transformed JUN-2 to the most transformed JUN-3, with regard to all the transformation characteristics studied, while the JUN-2fos-3 cell line exhibits a unique transformation mode, with little deregulation of cell growth and proliferation, but pronounced motility and invasiveness. The invasive sarcoma sublines JUN-2fos-3 and JUN-3 show complex metabolic profiles, with activation of both mitochondrial oxidative phosphorylation and glycolysis and a significant increase in spared respiratory capacity. The specific transcriptomic profile of invasive sublines features very complex biological relationships across the identified genes and proteins, with accentuated autocrine control of motility and angiogenesis. Pharmacologic inhibition of one of the autocrine motility factors identified, Ccl8, significantly diminished both motility and invasiveness of the highly transformed fibrosarcoma cell. This progression series could be greatly valuable for deciphering crucial aspects of sarcoma progression and defining new prognostic markers and potential therapeutic targets.

• Keywords
• Ccl8, fibrosarcoma, invasiveness, progression series, transcriptome,
• Publication type
• Journal Article MeSH

Observation and analysis of cancer cell behaviour in 3D environment is essential for full understanding of the mechanisms of cancer cell invasion. However, label-free imaging of live cells in 3D conditions is optically more challenging than in 2D. Quantitative phase imaging provided by coherence controlled holographic microscopy produces images with enhanced information compared to ordinary light microscopy and, due to inherent coherence gate effect, enables observation of live cancer cells' activity even in scattering milieu such as the 3D collagen matrix. Exploiting the dynamic phase differences method, we for the first time describe dynamics of differences in cell mass distribution in 3D migrating mesenchymal and amoeboid cancer cells, and also demonstrate that certain features are shared by both invasion modes. We found that amoeboid fibrosarcoma cells' membrane blebbing is enhanced upon constriction and is also occasionally present in mesenchymally invading cells around constricted nuclei. Further, we demonstrate that both leading protrusions and leading pseudopods of invading fibrosarcoma cells are defined by higher cell mass density. In addition, we directly document bundling of collagen fibres by protrusions of mesenchymal fibrosarcoma cells. Thus, such a non-invasive microscopy offers a novel insight into cellular events during 3D invasion.

• MeSH
• Cell Membrane metabolism   MeSH
• Cell Culture Techniques methods   MeSH
• Fibrosarcoma diagnostic imaging   pathology   MeSH
• Holography instrumentation   methods   MeSH
• Intravital Microscopy instrumentation   methods   MeSH
• Neoplasm Invasiveness diagnostic imaging   pathology   MeSH
• Collagen metabolism   MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Cell Movement * MeSH
• Pseudopodia metabolism   MeSH
• Imaging, Three-Dimensional instrumentation   methods   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Collagen MeSH

CAS is a docking protein, which was shown to act as a mechanosensor in focal adhesions. The unique assembly of structural domains in CAS is important for its function as a mechanosensor. The tension within focal adhesions is transmitted to a stretchable substrate domain of CAS by focal adhesion-targeting of SH3 and CCH domain of CAS, which anchor the CAS protein in focal adhesions. Mechanistic models of the stretching biosensor propose equal roles for both anchoring domains. Using deletion mutants and domain replacements, we have analyzed the relative importance of the focal adhesion anchoring domains on CAS localization and dynamics in focal adhesions as well as on CAS-mediated mechanotransduction. We confirmed the predicted prerequisite of the focal adhesion targeting for CAS-dependent mechanosensing and unraveled the critical importance of CAS SH3 domain in mechanosensing. We further show that CAS localizes to the force transduction layer of focal adhesions and that mechanical stress stabilizes CAS in focal adhesions.

• MeSH
• Cell Adhesion MeSH
• Mechanotransduction, Cellular * MeSH
• Fibroblasts cytology   metabolism   MeSH
• Focal Adhesions metabolism   MeSH
• Stress, Mechanical MeSH
• Mutant Proteins chemistry   MeSH
• Mice MeSH
• Protein Domains MeSH
• Recombinant Fusion Proteins metabolism   MeSH
• Signal Transduction MeSH
• Protein Stability MeSH
• Crk-Associated Substrate Protein chemistry   metabolism   MeSH
• Structure-Activity Relationship MeSH
• Green Fluorescent Proteins metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bcar1 protein, mouse MeSH Browser
• Mutant Proteins MeSH
• Recombinant Fusion Proteins MeSH
• Crk-Associated Substrate Protein MeSH
• Green Fluorescent Proteins MeSH

Apico-basal polarity is typical of cells present in differentiated epithelium while front-rear polarity develops in motile cells. In cancer development, the transition from epithelial to migratory polarity may be seen as the hallmark of cancer progression to an invasive and metastatic disease. Despite the morphological and functional dissimilarity, both epithelial and migratory polarity are controlled by a common set of polarity complexes Par, Scribble and Crumbs, phosphoinositides, and small Rho GTPases Rac, Rho and Cdc42. In epithelial tissues, their mutual interplay ensures apico-basal and planar cell polarity. Accordingly, altered functions of these polarity determinants lead to disrupted cell-cell adhesions, cytoskeleton rearrangements and overall loss of epithelial homeostasis. Polarity proteins are further engaged in diverse interactions that promote the establishment of front-rear polarity, and they help cancer cells to adopt different invasion modes. Invading cancer cells can employ either the collective, mesenchymal or amoeboid invasion modes or actively switch between them and gain intermediate phenotypes. Elucidation of the role of polarity proteins during these invasion modes and the associated transitions is a necessary step towards understanding the complex problem of metastasis. In this review we summarize the current knowledge of the role of cell polarity signaling in the plasticity of cancer cell invasiveness.

• Keywords
• AMT, EMT, invasion, plasticity, polarity,
• MeSH
• Neoplasm Invasiveness pathology   MeSH
• Humans MeSH
• Neoplasms pathology   MeSH
• Cell Polarity physiology   MeSH
• Signal Transduction physiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

BACKGROUND: The local invasion of tumor cells into the surrounding tissue is the first and most critical step of the metastatic cascade. Cells can invade either collectively, or individually. Individual cancer cell invasion can occur in the mesenchymal or amoeboid mode, which are mutually interchangeable. This plasticity of individual cancer cell invasiveness may represent an escape mechanism for invading cancer cells from anti-metastatic treatment. METHODS: To identify new signaling proteins involved in the plasticity of cancer cell invasiveness, we performed proteomic analysis of the amoeboid to mesenchymal transition with A375m2 melanoma cells in a 3D Matrigel matrix. RESULTS: In this screen we identified PKCα as an important protein for the maintenance of amoeboid morphology. We found that the activation of PKCα resulted in the mesenchymal-amoeboid transition of mesenchymal K2 and MDA-MB-231 cell lines. Consistently, PKCα inhibition led to the amoeboid-mesenchymal transition of amoeboid A375m2 cells. Next, we showed that PKCα inhibition resulted in a considerable decrease in the invading abilities of all analyzed cancer cell lines. CONCLUSIONS: Our results suggest that PKCα is an important protein for maintenance of the amoeboid morphology of cancer cells, and that downregulation of PKCα results in the amoeboid to mesenchymal transition. Our data also suggest that PKCα is important for both mesenchymal and amoeboid invasiveness, making it an attractive target for anti-metastatic therapies.

• MeSH
• Neoplasm Invasiveness genetics   pathology   MeSH
• Humans MeSH
• Melanoma genetics   pathology   MeSH
• Mesoderm metabolism   pathology   MeSH
• Cell Line, Tumor MeSH
• Cell Movement genetics   MeSH
• Protein Kinase C-alpha biosynthesis   genetics   MeSH
• Proteomics MeSH
• Gene Expression Regulation, Neoplastic MeSH
• Signal Transduction MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• PRKCA protein, human MeSH Browser
• Protein Kinase C-alpha MeSH

BACKGROUND: Although there is extensive evidence for the amoeboid invasiveness of cancer cells in vitro, much less is known about the role of amoeboid invasiveness in metastasis and the importance of Rho/ROCK/MLC signaling in this process. RESULTS: We analyzed the dependence of amoeboid invasiveness of rat and chicken sarcoma cells and the metastatic activity of chicken cells on individual elements of the Rho/ROCK/MLC pathway. In both animal models, inhibition of Rho, ROCK or MLC resulted in greatly decreased cell invasiveness in vitro, while inhibition of extracellular proteases using a broad spectrum inhibitor did not have a significant effect. The inhibition of both Rho activity and MLC phosphorylation by dominant negative mutants led to a decreased capability of chicken sarcoma cells to metastasize. Moreover, the overexpression of RhoA in non-metastatic chicken cells resulted in the rescue of both invasiveness and metastatic capability. Rho and ROCK, unlike MLC, appeared to be directly involved in the maintenance of the amoeboid phenotype, as their inhibition resulted in the amoeboid-mesenchymal transition in analyzed cell lines. CONCLUSION: Taken together, these results suggest that protease-independent invasion controlled by elements of the Rho/ROCK/MLC pathway can be frequently exploited by metastatic sarcoma cells.

• MeSH
• Neoplasm Invasiveness MeSH
• rho-Associated Kinases metabolism   MeSH
• Rats MeSH
• Chickens MeSH
• Myosin Light Chains metabolism   MeSH
• Cell Line, Tumor MeSH
• Cell Movement MeSH
• rho GTP-Binding Proteins metabolism   MeSH
• Sarcoma metabolism   pathology   MeSH
• Signal Transduction MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• rho-Associated Kinases MeSH
• Myosin Light Chains MeSH
• rho GTP-Binding Proteins MeSH

Metastatic spreading of cancer cells is a highly complex process directed primarily by the interplay between tumor microenvironment, cell surface receptors, and actin cytoskeleton dynamics. To advance our understanding of metastatic cancer dissemination, we have developed a model system that is based on two v-src transformed chicken sarcoma cell lines-the highly metastatic parental PR9692 and a non-metastasizing but fully tumorigenic clonal derivative PR9692-E9. Oligonucleotide microarray analysis of both cell lines revealed that the gene encoding the transcription factor EGR1 was downregulated in the non-metastatic PR9692-E9 cells. Further investigation demonstrated that the introduction of exogenous EGR1 into PR9692-E9 cells restored their metastatic potential to a level indistinguishable from parental PR9692 cells. Microarray analysis of EGR1 reconstituted cells revealed the activation of genes that are crucial for actin cytoskeleton contractility (MYL9), filopodia formation (MYO10), the production of specific extracellular matrix components (HAS2, COL6A1-3) and other essential pro-metastatic abilities.

• MeSH
• Cell Adhesion MeSH
• Cell Line MeSH
• Cytoskeleton metabolism   MeSH
• Phenotype MeSH
• Kinetics MeSH
• Chickens MeSH
• Neoplasm Metastasis genetics   MeSH
• Cell Transformation, Neoplastic genetics   pathology   MeSH
• Oncogene Protein pp60(v-src) genetics   metabolism   MeSH
• Cell Movement MeSH
• Cell Proliferation MeSH
• Early Growth Response Protein 1 genetics   metabolism   MeSH
• Gene Expression Regulation, Neoplastic MeSH
• Sarcoma genetics   pathology   MeSH
• Gene Expression Profiling MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Oncogene Protein pp60(v-src) MeSH
• Early Growth Response Protein 1 MeSH

During malignant neoplastic progression the cells undergo genetic and epigenetic cancer-specific alterations that finally lead to a loss of tissue homeostasis and restructuring of the microenvironment. The invasion of cancer cells through connective tissue is a crucial prerequisite for metastasis formation. Although cell invasion is foremost a mechanical process, cancer research has focused largely on gene regulation and signaling that underlie uncontrolled cell growth. More recently, the genes and signals involved in the invasion and transendothelial migration of cancer cells, such as the role of adhesion molecules and matrix degrading enzymes, have become the focus of research. In this review we discuss how the structural and biomechanical properties of extracellular matrix and surrounding cells such as endothelial cells influence cancer cell motility and invasion. We conclude that the microenvironment is a critical determinant of the migration strategy and the efficiency of cancer cell invasion.

• Publication type
• Journal Article MeSH

Tumor cells exhibit at least two distinct modes of migration when invading the 3D environment. A single tumor cell's invasive strategy follows either mesenchymal or amoeboid patterns. Certain cell types can use both modes of invasiveness and undergo transitions between them. This work outlines the signaling pathways involved in mesenchymal and amoeboid types of tumor cell motility and summarizes the molecular mechanisms that are involved in transitions between them. The focus is on the signaling of the Rho family of small GTPases that regulate the cytoskeleton-dependent processes taking place during the cell migration. The multiple interactions among the Rho family of proteins, their regulators and effectors are thought to be the key determinants of the particular type of invasiveness. Mesenchymal and amoeboid invasive strategies display different adhesive and proteolytical interactions with the surrounding matrix and the alterations influencing these interactions can also lead to the transitions.

• MeSH
• Cytoskeleton MeSH
• Neoplasm Invasiveness * MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Cell Movement * MeSH
• rac GTP-Binding Proteins metabolism   MeSH
• Signal Transduction MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• rac GTP-Binding Proteins MeSH