Breast cancer cell migration is regulated through junctional adhesion molecule-A-mediated activation of Rap1 GTPase.

Hdl Handle:
http://hdl.handle.net/10147/207138
Title:
Breast cancer cell migration is regulated through junctional adhesion molecule-A-mediated activation of Rap1 GTPase.
Authors:
McSherry, Elaine A; Brennan, Kieran; Hudson, Lance; Hill, Arnold D K; Hopkins, Ann M
Affiliation:
Department of Surgery, Royal College of Surgeons in Ireland, RCSI Education and, Research Centre, Smurfit Building, Beaumont Hospital, Dublin 9, Ireland.
Citation:
Breast Cancer Res. 2011 Mar 23;13(2):R31.
Journal:
Breast cancer research : BCR
Issue Date:
1-Feb-2012
URI:
http://hdl.handle.net/10147/207138
DOI:
10.1186/bcr2853
PubMed ID:
21429211
Abstract:
INTRODUCTION: The adhesion protein junctional adhesion molecule-A (JAM-A) regulates epithelial cell morphology and migration, and its over-expression has recently been linked with increased risk of metastasis in breast cancer patients. As cell migration is an early requirement for tumor metastasis, we sought to identify the JAM-A signalling events regulating migration in breast cancer cells. METHODS: MCF7 breast cancer cells (which express high endogenous levels of JAM-A) and primary cultures from breast cancer patients were used for this study. JAM-A was knocked down in MCF7 cells using siRNA to determine the consequences for cell adhesion, cell migration and the protein expression of various integrin subunits. As we had previously demonstrated a link between the expression of JAM-A and beta1-integrin, we examined activation of the beta1-integrin regulator Rap1 GTPase in response to JAM-A knockdown or functional antagonism. To test whether JAM-A, Rap1 and beta1-integrin lie in a linear pathway, we tested functional inhibitors of all three proteins separately or together in migration assays. Finally we performed immunoprecipitations in MCF7 cells and primary breast cells to determine the binding partners connecting JAM-A to Rap1 activation. RESULTS: JAM-A knockdown in MCF7 breast cancer cells reduced adhesion to, and migration through, the beta1-integrin substrate fibronectin. This was accompanied by reduced protein expression of beta1-integrin and its binding partners alphaV- and alpha5-integrin. Rap1 activity was reduced in response to JAM-A knockdown or inhibition, and pharmacological inhibition of Rap1 reduced MCF7 cell migration. No additive anti-migratory effect was observed in response to simultaneous inhibition of JAM-A, Rap1 and beta1-integrin, suggesting that they lie in a linear migratory pathway. Finally, in an attempt to elucidate the binding partners putatively linking JAM-A to Rap1 activation, we have demonstrated the formation of a complex between JAM-A, AF-6 and the Rap1 activator PDZ-GEF2 in MCF7 cells and in primary cultures from breast cancer patients. CONCLUSIONS: Our findings provide compelling evidence of a novel role for JAM-A in driving breast cancer cell migration via activation of Rap1 GTPase and beta1-integrin. We speculate that JAM-A over-expression in some breast cancer patients may represent a novel therapeutic target to reduce the likelihood of metastasis.
Language:
eng
ISSN:
1465-542X (Electronic); 1465-5411 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorMcSherry, Elaine Aen_GB
dc.contributor.authorBrennan, Kieranen_GB
dc.contributor.authorHudson, Lanceen_GB
dc.contributor.authorHill, Arnold D Ken_GB
dc.contributor.authorHopkins, Ann Men_GB
dc.date.accessioned2012-02-01T10:00:09Z-
dc.date.available2012-02-01T10:00:09Z-
dc.date.issued2012-02-01T10:00:09Z-
dc.identifier.citationBreast Cancer Res. 2011 Mar 23;13(2):R31.en_GB
dc.identifier.issn1465-542X (Electronic)en_GB
dc.identifier.issn1465-5411 (Linking)en_GB
dc.identifier.pmid21429211en_GB
dc.identifier.doi10.1186/bcr2853en_GB
dc.identifier.urihttp://hdl.handle.net/10147/207138-
dc.description.abstractINTRODUCTION: The adhesion protein junctional adhesion molecule-A (JAM-A) regulates epithelial cell morphology and migration, and its over-expression has recently been linked with increased risk of metastasis in breast cancer patients. As cell migration is an early requirement for tumor metastasis, we sought to identify the JAM-A signalling events regulating migration in breast cancer cells. METHODS: MCF7 breast cancer cells (which express high endogenous levels of JAM-A) and primary cultures from breast cancer patients were used for this study. JAM-A was knocked down in MCF7 cells using siRNA to determine the consequences for cell adhesion, cell migration and the protein expression of various integrin subunits. As we had previously demonstrated a link between the expression of JAM-A and beta1-integrin, we examined activation of the beta1-integrin regulator Rap1 GTPase in response to JAM-A knockdown or functional antagonism. To test whether JAM-A, Rap1 and beta1-integrin lie in a linear pathway, we tested functional inhibitors of all three proteins separately or together in migration assays. Finally we performed immunoprecipitations in MCF7 cells and primary breast cells to determine the binding partners connecting JAM-A to Rap1 activation. RESULTS: JAM-A knockdown in MCF7 breast cancer cells reduced adhesion to, and migration through, the beta1-integrin substrate fibronectin. This was accompanied by reduced protein expression of beta1-integrin and its binding partners alphaV- and alpha5-integrin. Rap1 activity was reduced in response to JAM-A knockdown or inhibition, and pharmacological inhibition of Rap1 reduced MCF7 cell migration. No additive anti-migratory effect was observed in response to simultaneous inhibition of JAM-A, Rap1 and beta1-integrin, suggesting that they lie in a linear migratory pathway. Finally, in an attempt to elucidate the binding partners putatively linking JAM-A to Rap1 activation, we have demonstrated the formation of a complex between JAM-A, AF-6 and the Rap1 activator PDZ-GEF2 in MCF7 cells and in primary cultures from breast cancer patients. CONCLUSIONS: Our findings provide compelling evidence of a novel role for JAM-A in driving breast cancer cell migration via activation of Rap1 GTPase and beta1-integrin. We speculate that JAM-A over-expression in some breast cancer patients may represent a novel therapeutic target to reduce the likelihood of metastasis.en_GB
dc.language.isoengen_GB
dc.titleBreast cancer cell migration is regulated through junctional adhesion molecule-A-mediated activation of Rap1 GTPase.en_GB
dc.contributor.departmentDepartment of Surgery, Royal College of Surgeons in Ireland, RCSI Education and, Research Centre, Smurfit Building, Beaumont Hospital, Dublin 9, Ireland.en_GB
dc.identifier.journalBreast cancer research : BCRen_GB
dc.description.provinceLeinster-

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