Celecoxib, a cyclooxygenase-2 inhibitor, potentiates the chemotherapic effect of vinorelbine in the medullary thyroid cancer TT cell line

► We analyzed the ability of celecoxib to sensitize TT cell line to vinorelbine as compared to doxorubicin. ► Celecoxib induced apoptosis and decreased drug efflux in TT cells. ► TT cells were 10-fold more resistant to doxorubicin than to vinorelbine. ► The association of celecoxib with vinorelbine, but not with doxorubicin, reduced cell viability and increased apoptosis.