Euxanthone Impairs the Metastatic Potential of Osteosarcoma by Reducing COX-2 Expression.

Osteosarcoma (OS) is one of the most common malignancies of bone. This study was aimed to explore the anti-metastatic effect of euxanthone on OS. Adhesion assay and Transwell assay were used to examine the effect of euxanthone on adhesion, migration and invasion of OS cells. COX-2-over-expressing plasmid was applied to transfect OS cells to assess whether COX-2 affects the anti-metastatic function of euxanthone. PDCD4 knockdown and miR-21 mimic were applied to assess whether euxanthone suppresses the transactivation of c-jun via modulating miR-21-PDCD4 signaling. The effect of euxanthone in vivo was also examined by lung metastasis assay. Euxanthone, a xanthone derivative extracted from Polygala caudata, has been found to exhibit anti-neoplastic activities. In present study, our results showed that euxanthone suppressed cell adhesion, migration, and invasion in OS cells. Our experimental data also showed that repression of COX-2 by euxanthone mediated its anti-metastatic activities. Moreover, our findings revealed that euxanthone modulated the COX-2 expression through the miR-21/PDCD4/c-jun signaling pathway. The anti-metastatic activities of euxanthone were also validated in a pulmonary metastasis model. Taken together, our results highlighted the potential of euxanthone to be used in the treatment of OS. Anat Rec, 302:1399-1408, 2019. © 2018 Wiley Periodicals, Inc.