Inhibition of AP-1 transcriptional activity blocks the migration, invasion, and experimental metastasis of murine osteosarcoma.

A well-characterized murine osteosarcoma model for metastasis and invasion was used in this study to determine the role of AP-1 in the progression of this disease. We analyzed K12 and K7M2 cells, two clonally related murine osteosarcoma cell lines that have been characterized as low metastatic or high metastatic, respectively, for AP-1 components and activity. AP-1 DNA binding was similar between the two cell lines; however AP-1 transcriptional activity was enhanced by 3- to 5-fold in K7M2 cells relative to that in K12 cells.