c-Jun N-terminal kinase is involved in motility of endothelial cell

Cell motility is essential for a wide range of cellular activities including anigogenesis as well as metastasis of tumor cells. Ras has been implicated in cell migration and invasion, and functions at upstream of mitogen-activated protein kinase (MAPK) families, which include extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK. In the present study, we examined the role of JNK in endothelial cell motility using stable transfectant (DAR-ECV) of ECV304 endothelial cells expressing previously established oncogenic H-Ras (leu 61). DAR-ECV cells showed an enhanced angiogenic potential and motility (approximately 2-fold) compared to ECV304 cells. Western blot analysis revealed constitutive activation of JNK in DAR-ECV cells. Pretreatment of JNK specific inhibitors, curcumin and all trans-retinoic acid, decreased the basal motility of DAR-ECV cells in a dose-dependent manner. These inhibitors also suppressed the motility stimulated by known JNK agonists such as TNFalpha and anisomycin. To further confirm the role of JNK, ECV304 cells expressing dominant active SEK1 (DAS-ECV) were generated. Basal non-stimulated levels of the cellular migration were greater in DAS-ECV clones than those in control ECV304 cells. These results suggest that Ras-SEK1-JNK pathway regulates motility of endothelial cells during angiogenesis.

c-Jun N-terminal kinase is involved in motility of endothelial cell

Cell motility is essential for a wide range of cellular activities including anigogenesis as well as metastasis of tumor cells. Ras has been implicated in cell migration and invasion, and functions at upstream of mitogen-activated protein kinase (MAPK) families, which include extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK. In the present study, we examined the role of JNK in endothelial cell motility using stable transfectant (DAR-ECV) of ECV304 endothelial cells expressing previously established oncogenic H-Ras (leu 61). DAR-ECV cells showed an enhanced angiogenic potential and motility (approximately 2-fold) compared to ECV304 cells. Western blot analysis revealed constitutive activation of JNK in DAR-ECV cells. Pretreatment of JNK specific inhibitors, curcumin and all trans-retinoic acid, decreased the basal motility of DAR-ECV cells in a dose-dependent manner. These inhibitors also suppressed the motility stimulated by known JNK agonists such as TNFalpha and anisomycin. To further confirm the role of JNK, ECV304 cells expressing dominant active SEK1 (DAS-ECV) were generated. Basal non-stimulated levels of the cellular migration were greater in DAS-ECV clones than those in control ECV304 cells. These results suggest that Ras-SEK1-JNK pathway regulates motility of endothelial cells during angiogenesis.

The role of plasminogen activator receptor in cancer invasion and dormancy

Urokinase plasminogen activator receptor (uPAR) has been identified some 15 years ago and the anticipation was that is presence on the cell surface will provide a focus for anchoring uPA and possibly protect the enzyme from native inhibitors. The studies of the last decade have shown that uPA localized to the surface of cells by uPAR is indeed an important factor in the process of cancer cell invasion and metastasis. We developed a chick embryo model in which we showed that uPAR is crucial in invasion of stroma and in intravasation (breaching of the blood vessels walls). More recently and unexpectedly, uPAR-a protein anchored in the outer leaflet of the plasma membrane, has been shown to initiate signal transduction events and affect cell migration. We have shown that uPAR co-associates with fibronectin binding integrin, alpha5beta1, activates them and that this interaction leads to a greatly increased level of active ERK. When the association between uPAR and integrin or integrin and fibronectin are interrupted either by reduction of surface uPAR expression, or by other means, human carcinoma cells enter a state of protracted dormancy. We show that very high levels of active ERK are required to keep cancer cells proliferating in vivo.

Relación entre el activador del plasminógeno tipo urocinasa y el cáncer: mecanismo de regulación y control / Relation between urokinase-type plasminogen activator and cancer mechanims of regulation and control

Son analizados y discutidos los aspectos fisiológicos, bioquímicos y reguladores de la formación de plasmina por el activador de plasminógeno tipo urocinasa (uAP), así como su relación con el cáncer. En el cáncer, la activación del plasminógeno en la superficie celular ha mostrado ser esencial en la degradación de la matriz extracelular, en la disolución de la membrana basal, en los procesos de invasión y en las metástasis. La capacidad de las células para producir plasmina sobre su superficie celular depende de la presencia de uAP y del receptor del plasminógeno; ambos son las base de la regulación del sistema activante del plasminógeno in vivo