Functional Relevance of Urinary-type Plasminogen Activator Receptor-α3β1 Integrin Association in Proteinase Regulatory Pathways

Abstract

Squamous cell carcinoma of the oral cavity is characterized by persistent, disorganized expression of integrin α3β1 and enhanced production of urinary-type plasminogen activator (uPA) and its receptor (uPAR) relative to normal oral mucosa. Because multivalent aggregation of α3β1 integrin up-regulates uPA and induces a dramatic co-clustering of uPAR, we explored the hypothesis that lateral ligation of α3β1 integrin by uPAR contributes to uPA regulation in oral mucosal cells. To investigate mechanisms by which uPAR/α3β1 binding enhances uPA expression, integrin-dependent signal activation was assessed. Both Src and ERK1/2 in to integrin and Src ERK1/2 activation and uPA of receptor uPA the and of the in the uPA the Because uPAR is to α3β1 the uPAR/α3β1 in uPA regulation was assessed. of α3β1 in the of a that uPAR/α3β1 integrin binding uPA of cell uPAR uPA integrin α3β1 a in which a to uPAR, uPA expression integrin the of uPAR in of uPAR/α3β1 binding and that a integrin uPAR/α3β1 signal in activation of uPA expression and enhanced Squamous cell carcinoma of the oral cavity is characterized by persistent, disorganized expression of integrin α3β1 and enhanced production of urinary-type plasminogen activator (uPA) and its receptor (uPAR) relative to normal oral mucosa. Because multivalent aggregation of α3β1 integrin up-regulates uPA and induces a dramatic co-clustering of uPAR, we explored the hypothesis that lateral ligation of α3β1 integrin by uPAR contributes to uPA regulation in oral mucosal cells. To investigate mechanisms by which uPAR/α3β1 binding enhances uPA expression, integrin-dependent signal activation was assessed. Both Src and ERK1/2 in to integrin and Src ERK1/2 activation and uPA of receptor uPA the and of the in the uPA the Because uPAR is to α3β1 the uPAR/α3β1 in uPA regulation was assessed. of α3β1 in the of a that uPAR/α3β1 integrin binding uPA of cell uPAR uPA integrin α3β1 a in which a to uPAR, uPA expression integrin the of uPAR in of uPAR/α3β1 binding and that a integrin uPAR/α3β1 signal in activation of uPA expression and enhanced cell carcinoma oral cell urinary-type plasminogen uPAR, uPA cell oral cell urinary-type plasminogen uPAR, uPA cell is the of the oral a is and the and that of and and enhanced expression of the plasminogen activator (uPA) and the integrin of uPA plasminogen to a and of uPA is the of its cell receptor and its plasminogen activator to cell and in and in uPAR is a cell that uPA and to the of by the of a and and of uPAR, regulation of cell and cell and that uPAR uPA binding to its uPAR, to uPA in its a receptor to binding which in of uPAR of and that to the and and the that the uPAR lateral and binding to integrin Src to a the uPAR to binding to and expression and cell the regulation of uPA in oral we that multivalent aggregation of integrin α3β1 up-regulates uPA expression a a was by a of uPAR to of α3β1 and of a and was by binding of uPAR to α3β1 in and of a that uPAR/α3β1 integrin binding the was to in the and a in the was that uPAR binding of was to the of uPAR/α3β1 to regulation of uPA expression and a of α3β1 integrin uPAR/α3β1 signal in enhanced uPA expression and in oral and by integrin and and was which and was of Src and uPAR and and uPA and enhanced and oral a of normal oral by of and cell carcinoma of the oral cavity in the and in the and in and and and cell integrin integrin in and the in and of to the cell by the of a of and to in the in and and to of the the uPA the cell of the was of to to the of integrin to by of the of the of and to a the of was in and in of was and in of of was to the in and a which of and and in of plasminogen activator in was a to plasminogen activation and the of a Because the uPA and plasminogen activator of the uPA to the plasminogen activator in cells. of the oral cell plasminogen and of the plasminogen in the was to the to the of the uPA was by the uPA was and the of the to the by To the a was to and by and by in normal and of the and the integrin integrin the and and the by to and relative to of and Src the of and the in by the and was the and of and to to ERK1/2 expression to the of Src to the of of was to of and to and cells. and was and the of the by and in and a by the and the the to and a of in was to of and and was the was the and the was the cell and to of uPAR by expression of uPAR was by of uPAR and the a in the and in the uPAR in a and in by to by in and and by To cell of of the was by in to the by and uPAR of relative of in was of and to a of was and the the of and and in of in of a a the of in the cell was the and of and and and the and by of was by the in the of by of of was a to the in of of the the a the and and the to the of the and a of relative of uPA uPAR uPA of by signal by the of signal a and of and is by the of the integrin by integrin and in of the integrin to activation of of by a multivalent by to a characterized by the of a of and the of the by integrin of oral to and α3β1 in in the of in a in uPA and to a that multivalent α3β1 integrin integrin to α3β1 the cell by of uPA in in uPA was in the of and oral in to integrin relative to the integrin uPA expression and mechanisms by which integrin uPA expression, the of to by integrin in the of Src receptor by integrin to of and uPA and and and of the and the Src the production of uPA in to α3β1 integrin and of integrin α3β1 of Src and and of Src the of that the activation of is of Src of in α3β1 uPA expression of uPA by integrin activation of and Src To the in integrin of uPA the in Src in the of the was and uPA and the and the and of was in and and Src and and and of in to of uPA in the the in the of the and uPA and and integrin uPA and and integrin ERK1/2 of the and to uPA expression in cell oral the of in uPA regulation was uPA in and was by the of α3β1 integrin in of the of by the of uPA expression integrin of uPA regulation by and α3β1 induces uPA activation in oral and we that uPA expression is by the To uPA expression was to activation of the uPA the to of the uPA the uPA and the to and of of uPA expression the of α3β1 integrin to in in the uPA of the to activation in activation was by of the α3β1 induces activation of the uPA the a uPA to the of the and in by integrin the cell to uPA that multivalent aggregation of α3β1 integrin to of uPA expression a a Because integrin induces a dramatic of uPAR to of and of α3β1 and uPAR the uPAR/α3β1 integrin in regulation of expression was a was a the of integrin that was to uPAR and integrin and was that uPAR binding to α3β1 that uPAR binding to α3β1 integrin a to the of integrin of α3β1 in the of uPA expression that uPAR/α3β1 binding is of that to of uPA α3β1 uPA expression of uPAR was to uPA expression of of uPA in the of and to integrin of of the integrin in the of the uPA a the a was to the of uPAR/α3β1 integrin to uPA in integrin expression in the of integrin to uPAR/α3β1 and the to to of integrin uPA expression was by the the was by of that the is of uPAR to and of the integrin in and uPA expression was in the that uPAR/α3β1 lateral the of uPAR in expression in of and and the integrin and uPA relative to the uPA in to integrin integrin and in uPA the integrin integrin and and to and integrin relative to a and oral integrin and the by and by to that the relative of integrin binding to integrin is of uPAR was to the of uPAR/α3β1 integrin in relative in uPAR of was by and and in of uPAR the of uPA in to integrin a of uPAR α3β1 integrin in activation of in and activation was in uPAR a the of ERK1/2 of uPAR in the of uPA α3β1 integrin the hypothesis that uPAR/α3β1 integrin integrin that regulation in to of uPAR expression uPA and uPAR and and and uPAR and integrin expression by expression of integrin and uPAR by and and and that relative uPAR the relative of integrin expression by uPAR a and a uPAR integrin to and ERK1/2 and uPAR and and uPA of the a in uPAR, by the relative to of uPAR/α3β1 that uPA contributes to the of and oral of a is by the of that to the of the of and that in of by of of that uPAR is in the integrin was in the Because the uPAR is in the the uPAR/α3β1 is enhanced in the of uPAR is in the of of was in the and its in cell was in the of uPAR/α3β1 binding in a in in the a a in was in the of the is to the of uPA uPA and uPAR of is to uPAR the a in was relative to a uPAR a in uPAR by and is by the of the hypothesis that uPAR/α3β1 is of of uPAR/α3β1 a a the by the of the and of was by uPAR, and in in the of cell was the and of and the relative of is in in the of the and of relative to of and uPAR to the of in the of uPA uPA uPAR uPAR uPA was in of relative to is the of the oral oral in the in a of and the in a a of the that a of the and that to is a to the of and that of To of and and the uPA and the integrin of and a α3β1 and of normal oral is by a a and and of enhanced in the in of is in to carcinoma that is by the hypothesis is by the and is in α3β1 and the was to a to the of in the is the of that persistent, α3β1 integrin and of cell that enhanced α3β1 integrin expression to expression of α3β1 and is characterized by enhanced expression of uPA and its receptor uPAR relative to the normal oral mucosa. in uPA the mechanisms that uPA expression in that binding integrin a the uPAR to and in regulation of expression, cell and that α3β1 integrin a in activation of the uPA α3β1 integrin and uPAR is uPA uPA expression is by of binding of of uPAR, and expression of a that lateral the hypothesis that uPAR/α3β1 integrin enhanced expression in to integrin to the relative and of cell that the of uPAR to a α3β1 to activation of in that integrin a of α3β1 integrin uPAR/α3β1 signal in activation of the uPA we that uPAR/α3β1 is in in and cell carcinoma oral cell urinary-type plasminogen uPAR, uPA cell oral cell urinary-type plasminogen uPAR, uPA cell is the of the oral a is and the and that of and and enhanced expression of the plasminogen activator (uPA) and the integrin of uPA plasminogen to a and of uPA is the of its cell receptor and its plasminogen activator to cell and in and in uPAR is a cell that uPA and to the of by the of a and and of uPAR, regulation of cell and cell and that uPAR uPA binding to its uPAR, to uPA in its a receptor to binding which in of uPAR of and that to the and and the that the uPAR lateral and binding to integrin Src to a the uPAR to binding to and expression and cell the regulation of uPA in oral we that multivalent aggregation of integrin α3β1 up-regulates uPA expression a a was by a of uPAR to of α3β1 and of a and was by binding of uPAR to α3β1 in and of a that uPAR/α3β1 integrin binding the was to in the and a in the was that uPAR binding of was to the of uPAR/α3β1 to regulation of uPA expression and a of α3β1 integrin uPAR/α3β1 signal in enhanced uPA expression and in oral and by integrin and and was which and was of Src and uPAR and and uPA and enhanced and oral a of normal oral by of and cell carcinoma of the oral cavity in the and in the and in and and and cell integrin integrin in and the in and of to the cell by the of a of and to in the in and and to of the the uPA the cell of the was of to to the of integrin to by of the of the of and to a the of was in and in of was and in of of was to the in and a which of and and in of plasminogen activator in was a to plasminogen activation and the of a Because the uPA and plasminogen activator of the uPA to the plasminogen activator in cells. of the oral cell plasminogen and of the plasminogen in the was to the to the of the uPA was by the uPA was and the of the to the by To the a was to and by and by in normal and of the and the integrin integrin the and and the by to and relative to of and Src the of and the in by the and was the and of and to to ERK1/2 expression to the of Src to the of of was to of and to and cells. and was and the of the by and in and a by the and the the to and a of in was to of and and was the was the and the was the cell and to of uPAR by expression of uPAR was by of uPAR and the a in the and in the uPAR in a and in by to by in and and by To cell of of the was by in to the by and uPAR of relative of in was of and to a of was and the the of and and in of in of a a the of in the cell was the and of and and and the and by of was by the in the of by of of was a to the in of of the the a the and and the to the of the and a of relative of uPA uPAR uPA and by integrin and and was which and was of Src and uPAR and and uPA and enhanced and oral a of normal oral by of and cell carcinoma of the oral cavity in the and in the and in and and and cell integrin integrin in and the in and of to the cell by the of a of and to in the in and and to of the the uPA the cell of the was of to to the of integrin to by of the of the of and to a the of was in and in of was and in of of was to the in and a which of and and in of uPA plasminogen activator in was a to plasminogen activation and the of a Because the uPA and plasminogen activator of the uPA to the plasminogen activator in cells. of the oral cell plasminogen and of the plasminogen in the was to uPA the to the of the uPA was by the uPA was and the of the to the by To the a was to and by and by in normal and of the and the integrin integrin the and and the by to and relative to cells. of and Src the of and the in by the and was the and of and to to ERK1/2 expression to the of Src to the of of was to of and to and cells. and was and the of the by and in and a by the and the the to and a of in was to of and and was the was the and the was the cell and to of uPAR by expression of uPAR was by of uPAR and the a in the and in the uPAR in a and in by to by in and and by To cell of of the was by in to the by and uPAR of relative of in was of and to a of was and the the of and and in of in of a a the of in the cell was the and of and and and the and by of was by the in the of by of of was a to the in of of the the a the and and the to the of the and a of relative of uPA uPAR uPA of by signal by the of signal a and of and is by the of the integrin by integrin and in of the integrin to activation of of by a multivalent by to a characterized by the of a of and the of the by integrin of oral to and α3β1 in in the of in a in uPA and to a that multivalent α3β1 integrin integrin to α3β1 the cell by of uPA in in uPA was in the of and oral in to integrin relative to the integrin uPA expression and mechanisms by which integrin uPA expression, the of to by integrin in the of Src receptor by integrin to of and uPA and and and of the and the Src the production of uPA in to α3β1 integrin and of integrin α3β1 of Src and and of Src the of that the activation of is of Src of in α3β1 uPA expression of uPA in the the in the of the and uPA and and integrin uPA and and integrin ERK1/2 of the and to uPA expression in cell oral the of in uPA regulation was uPA in and was by the of α3β1 integrin in of the of by the of uPA expression integrin of uPA regulation by and α3β1 induces uPA activation in oral and we that uPA expression is by the To uPA expression was to activation of the uPA the to of the uPA the uPA and the to and of of uPA expression the of α3β1 integrin to in in the uPA of the to activation in activation was by of the α3β1 induces activation of the uPA the a uPA to the of the and in by integrin the cell to uPA that multivalent aggregation of α3β1 integrin to of uPA expression a a Because integrin induces a dramatic of uPAR to of and of α3β1 and uPAR the uPAR/α3β1 integrin in regulation of expression was a was a the of integrin that was to uPAR and integrin and was that uPAR binding to α3β1 that uPAR binding to α3β1 integrin a to the of integrin of α3β1 in the of uPA expression that uPAR/α3β1 binding is of that to of uPA α3β1 uPA expression of uPAR was to uPA expression of of uPA in the of and to integrin of of the integrin in the of the uPA a the a was to the of uPAR/α3β1 integrin to uPA in integrin expression in the of integrin to uPAR/α3β1 and the to to of integrin uPA expression was by the the was by of that the is of uPAR to and of the integrin in and uPA expression was in the that uPAR/α3β1 lateral the of uPAR in expression in of and and the integrin and uPA relative to the uPA in to integrin integrin and in uPA the integrin integrin and and to and integrin relative to a and oral integrin and the by and by to that the relative of integrin binding to integrin is of uPAR was to the of uPAR/α3β1 integrin in relative in uPAR of was by and and in of uPAR the of uPA in to integrin a of uPAR α3β1 integrin in activation of in and activation was in uPAR a the of ERK1/2 of uPAR in the of uPA α3β1 integrin the hypothesis that uPAR/α3β1 integrin integrin that regulation in to of uPAR expression uPA and uPAR and and and uPAR and integrin expression by expression of integrin and uPAR by and and and that relative uPAR the relative of integrin expression by uPAR a and a uPAR integrin to and ERK1/2 and uPAR and and uPA of the a in uPAR, by the relative to of uPAR/α3β1 that uPA contributes to the of and oral of a is by the of that to the of the of and that in of by of of that uPAR is in the integrin was in the Because the uPAR is in the the uPAR/α3β1 is enhanced in the of uPAR is in the of of was in the and its in cell was in the of uPAR/α3β1 binding in a in in the a a in was in the of the is to the of uPA uPA and uPAR of is to uPAR the a in was relative to a uPAR a in uPAR by and is by the of the hypothesis that uPAR/α3β1 is of of uPAR/α3β1 a a the by the of the and of was by uPAR, and in in the of cell was the and of and the relative of is in in the of the and of relative to of and uPAR to the of in the of uPA uPA uPAR uPAR uPA was in of relative to of by signal by the of signal a and of and is by the of the integrin by integrin and in of the integrin to activation of of by a multivalent by to a characterized by the of a of and the of the by integrin of oral to and α3β1 in in the of in a in uPA and to a that multivalent α3β1 integrin integrin to α3β1 the cell by of uPA in in uPA was in the of and oral in to integrin relative to the integrin uPA expression and To mechanisms by which integrin uPA expression, the of to by integrin in the of Src receptor by integrin to of and uPA and and and of the and the Src the production of uPA in to α3β1 integrin and of integrin α3β1 of Src and and of Src the of that the activation of is of Src of in α3β1 uPA expression Because integrin ERK1/2 of the and to uPA expression in cell oral the of in uPA regulation was uPA in and was by the of α3β1 integrin in of the of by the of uPA expression integrin of uPA regulation by and α3β1 induces uPA activation in oral and we that uPA expression is by the To uPA expression was to activation of the uPA the to of the uPA the uPA and the to and of of uPA expression the of α3β1 integrin to in in the uPA of the to activation in activation was by of the uPAR to uPA that multivalent aggregation of α3β1 integrin to of uPA expression a a Because integrin induces a dramatic of uPAR to of and of α3β1 and uPAR the uPAR/α3β1 integrin in regulation of expression was a was a the of integrin that was to uPAR and integrin and was that uPAR binding to α3β1 that uPAR binding to α3β1 integrin a to the of integrin of α3β1 in the of uPA expression that uPAR/α3β1 binding is of that to of uPA α3β1 uPA expression of uPAR was to uPA expression the a was to the of uPAR/α3β1 integrin to uPA in integrin expression in the of integrin to uPAR/α3β1 and the to to of integrin uPA expression was by the the was by of that the is of uPAR to and of the integrin in and uPA expression was in the that uPAR/α3β1 lateral the of uPAR in expression in of uPAR was to the of uPAR/α3β1 integrin in relative in uPAR of was by and and in of uPAR the of uPA in to integrin a of uPAR α3β1 integrin in activation of in and activation was in uPAR a the of ERK1/2 of uPAR in the of uPA α3β1 integrin the hypothesis that uPAR/α3β1 integrin integrin that regulation in to of uPAR/α3β1 that uPA contributes to the of and oral of a is by the of that to the of the of and that in of by of of that uPAR is in the integrin was in the Because the uPAR is in the the uPAR/α3β1 is enhanced in the of uPAR is in the of of was in the and its in cell was in the of uPAR/α3β1 binding in a in in the a a in was in the of the is to the of uPA uPA and uPAR of is to uPAR the a in was relative to a uPAR a in uPAR by and is by the of the hypothesis that uPAR/α3β1 is of is the of the oral oral in the in a of and the in a a of the that a of the and that to is a to the of and that of To of and and the uPA and the integrin of and a α3β1 and of normal oral is by a a and and of enhanced in the in of is in to carcinoma that is by the hypothesis is by the and is in α3β1 and the was to a to the of in the is the of that persistent, α3β1 integrin and of cell that enhanced α3β1 integrin expression to expression of α3β1 and is characterized by enhanced expression of uPA and its receptor uPAR relative to the normal oral mucosa. in uPA the mechanisms that uPA expression in that binding integrin a the uPAR to and in regulation of expression, cell and that α3β1 integrin a in activation of the uPA α3β1 integrin and uPAR is uPA uPA expression is by of binding of of uPAR, and expression of a that lateral the hypothesis that uPAR/α3β1 integrin enhanced expression in to integrin to the relative and of cell that the of uPAR to a α3β1 to activation of in that integrin a of α3β1 integrin uPAR/α3β1 signal in activation of the uPA we that uPAR/α3β1 is in in and is the of the oral oral in the in a of and the in a a of the that a of the and that to is a to the of and that of To of and and the uPA and the integrin of and a α3β1 and of normal oral is by a a and and of enhanced in the in of is in to carcinoma that is by the hypothesis is by the and is in α3β1 and the was to a to the of in the is the of that persistent, α3β1 integrin and of cell that enhanced α3β1 integrin expression to expression of α3β1 and is characterized by enhanced expression of uPA and its receptor uPAR relative to the normal oral mucosa. in uPA the mechanisms that uPA expression in that binding integrin a the uPAR to and in regulation of expression, cell and that α3β1 integrin a in activation of the uPA α3β1 integrin and uPAR is uPA uPA expression is by of binding of of uPAR, and expression of a that lateral the hypothesis that uPAR/α3β1 integrin enhanced expression in to integrin to the relative and of cell that the of uPAR to a α3β1 to activation of in that integrin a of α3β1 integrin uPAR/α3β1 signal in activation of the uPA we that uPAR/α3β1 is in in and