Maspin retards cell detachment via a novel interaction with the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system. Export

@article{citeulike:887072, abstract = {It is well documented that tumor suppressive maspin inhibits tumor cell invasion and extracellular matrix remodeling. Maspin is a cytosolic, cell surface-associated, and secreted protein in the serine protease inhibitor superfamily. Although several molecules have been identified as candidate intracellular maspin targets, the extracellular maspin target(s) remains elusive. Although maspin does not directly inhibit urokinase-type plasminogen activator (uPA) activity, we have shown evidence that maspin may block the pericellular proteolysis mediated by cell surface-associated uPA. In the current study, maspin significantly inhibited the Ca2+ reduction-induced detachment of DU145 cells. This maspin effect was associated with increased and sustained levels of mature focal adhesion contacts (FAC). We noted that maspin (a) colocalized with uPA and uPA receptor (uPAR), (b) enhanced the interaction between uPAR and low-density lipoprotein receptor related protein, and (c) induced rapid internalization of uPA and uPAR. The maspin effects on surface-associated uPA and uPAR required the interaction between uPA and uPAR. Further biochemical and biophysical analyses revealed that maspin specifically bound to pro-uPA with a deduced K(d) of 270 nmol/L and inhibited the plasmin-mediated pro-uPA cleavage. Interestingly, substitution of maspin p1' site Arg340 in the reactive site loop (RSL) with alanine not only abolished the binding to pro-uPA but also diminished the maspin effects on pro-uPA cleavage and cell detachment. These data show an important role of maspin RSL in regulating the uPA/uPAR-dependent cell detachment. Together, our data led to a new hypothesis that maspin may stabilize mature FACs by quenching localized uPA/uPAR complex before uPA activation.}, address = {Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.}, author = {Yin, S. and Lockett, J. and Meng, Y. and Biliran, H. and Blouse, G. E. and Li, X. and Reddy, N. and Zhao, Z. and Lin, X. and Anagli, J. and Cher, M. L. and Sheng, S.}, citeulike-article-id = {887072}, citeulike-linkout-0 = {http://dx.doi.org/10.1158/0008-5472.CAN-05-3514}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16618739}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16618739}, day = {15}, doi = {10.1158/0008-5472.CAN-05-3514}, issn = {0008-5472}, journal = {Cancer Res}, keywords = {nagamine}, month = {April}, number = {8}, pages = {4173--4181}, posted-at = {2006-10-06 09:25:28}, priority = {2}, title = {Maspin retards cell detachment via a novel interaction with the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system.}, url = {http://dx.doi.org/10.1158/0008-5472.CAN-05-3514}, volume = {66}, year = {2006} }

TY - JOUR ID - citeulike:887072 L3 - citeulike-article-id:887072 N2 - It is well documented that tumor suppressive maspin inhibits tumor cell invasion and extracellular matrix remodeling. Maspin is a cytosolic, cell surface-associated, and secreted protein in the serine protease inhibitor superfamily. Although several molecules have been identified as candidate intracellular maspin targets, the extracellular maspin target(s) remains elusive. Although maspin does not directly inhibit urokinase-type plasminogen activator (uPA) activity, we have shown evidence that maspin may block the pericellular proteolysis mediated by cell surface-associated uPA. In the current study, maspin significantly inhibited the Ca2+ reduction-induced detachment of DU145 cells. This maspin effect was associated with increased and sustained levels of mature focal adhesion contacts (FAC). We noted that maspin (a) colocalized with uPA and uPA receptor (uPAR), (b) enhanced the interaction between uPAR and low-density lipoprotein receptor related protein, and (c) induced rapid internalization of uPA and uPAR. The maspin effects on surface-associated uPA and uPAR required the interaction between uPA and uPAR. Further biochemical and biophysical analyses revealed that maspin specifically bound to pro-uPA with a deduced K(d) of 270 nmol/L and inhibited the plasmin-mediated pro-uPA cleavage. Interestingly, substitution of maspin p1' site Arg340 in the reactive site loop (RSL) with alanine not only abolished the binding to pro-uPA but also diminished the maspin effects on pro-uPA cleavage and cell detachment. These data show an important role of maspin RSL in regulating the uPA/uPAR-dependent cell detachment. Together, our data led to a new hypothesis that maspin may stabilize mature FACs by quenching localized uPA/uPAR complex before uPA activation. IS - 8 JF - Cancer Res SN - 0008-5472 AD - Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. EP - 4181 TI - Maspin retards cell detachment via a novel interaction with the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system. VL - 66 SP - 4173 KW - nagamine AU - Yin, S AU - Lockett, J AU - Meng, Y AU - Biliran, H AU - Blouse, GE AU - Li, X AU - Reddy, N AU - Zhao, Z AU - Lin, X AU - Anagli, J AU - Cher, ML AU - Sheng, S PY - 2006/04/15/ UR - http://dx.doi.org/10.1158/0008-5472.CAN-05-3514 ER -