BACKGROUND The role of epacl, an exchange protein activated by cAMP. in melanoma migration is largely unknown. Heparan sulfate (HS), a major ECM, and syndecan2, a HS-binding protein on the cell surface, play important roles in regulating such migration. Synde- can2, when activated, translocates to lipid-rich plasma microdomains, known as lipid rafts. We thus examined the role of epacl in HS production and syndecan2 transloca¬tion in melanoma migration. METHODS SK-MF.L-2, a human melanoma cell line, and migration assays with Boyden cham¬bers were employed. RESULTS Activation of Epacl adenoviral Epacl overexprcssiotl or HpMeOPT, at) Epac-specif- ic cAMP analog, significantly increased cell migration in a time- and dose-dependent manner. Epacl also increased HS production by 2-fold, and the removal of HS abol¬ished Epacl-induced migration. Epacl also increased expression of N-deacetylase/N- sulfotransferase-1 (NDST-1), a key synthetic enzyme for HS. Sucrose gradient frac¬tionation showed that Epacl increased syndecan2 translocation to rafts. In addition, disruption of rafts with lipid depletion abolished Epacl-induced migration. SUMMARY Epacl increased migration in malignant melanoma through HS production and syn- decan2 translocation to rafts.

BACKGROUNDThe role of epacl, an exchange protein activated by cAMP. in melanoma migration is largely unknown. Heparan sulfate (HS), a major ECM, and syndecan2, a HS-binding protein on the cell surface, play important roles in regulating such migration. Synde- can2, when activated, translocates to lipid-rich plasma microdomains, known as lipid rafts. We thus examined the role of epacl in HS production and syndecan2 transloca¬tion in melanoma migration. METHODSSK-MF.L-2, a human melanoma cell line, and migration assays with Boyden cham¬bers were employed.RESULTSActivation of Epacl adenoviral Epacl overexprcssiotl or HpMeOPT, at) Epac-specif- ic cAMP analog, significantly increased cell migration in a time- and dose-dependent manner. Epacl also increased HS production by 2-fold, and the removal of HS abol¬ished Epacl-induced migration. Epacl also increased expression of N-deacetylase/N- sulfotransferase-1 (NDST-1), a key synthetic enzyme for HS. Sucrose gradient frac¬tionation showed that Epacl increased syndecan2 translocation to rafts. In addition, disruption of rafts with lipid depletion abolished Epacl-induced migration.SUMMARYEpacl increased migration in malignant melanoma through HS production and syn- decan2 translocation to rafts.