Targeting DUSP5 suppresses malignant phenotypes of BRAF-mutant thyroid cancer cells and improves their response to sorafenib.

PURPOSE: The role of dual-specificity phosphatase-5 (DUSP5) in BRAF-mutant thyroid cancers remains unclear. The aims of this study are to investigate the role of DUSP5 in BRAF-mutant thyroid cancer cells, explore its value in the diagnosis and evaluate therapeutic potential of targeting DUSP5 combined with sorafenib for BRAF-mutant thyroid cancer patients.

METHODS: The role of DUSP5 in thyroid cancer cells was determined by a series of in vitro and in vivo experiments. Underlying mechanisms were explored by western blotting analysis. The diagnostic value of combination detection of DUSP5 expression and BRAFV600E mutation was evaluated using ROC curve.

RESULTS: Knocking down DUSP5 in BRAF-mutant thyroid cancer cells significantly inhibited colony formation, cell migration and invasion, meanwhile, induced cell cycle arrest and cell apoptosis. Moreover, inhibition of DUSP5 improved the anti-tumor efficacy of sorafenib both in vitro and in vivo. Besides, combination detection of DUSP5 expression and BRAFV600E mutation showed much more accuracy in preoperative diagnosis of thyroid cancer.

CONCLUSIONS: Our data demonstrate an oncogenic role of DUSP5 in BRAF-mutant thyroid cancer cells, and combined analysis of its expression and BRAFV600E mutation can accurately diagnose thyroid cancer. In addition, inhibition of DUSP5 improves the response of BRAF-mutant thyroid cancer cells to sorafenib.