Trps1 is associated with the multidrug resistance of osteosarcoma by regulating MDR1 gene expression

Multidrug resistance (MDR) is a significant clinical problem in the chemotherapy of osteosarcoma and has been linked to the cellular expression of several multidrug-efflux transporters such as MDR1/P-gp. Our inhibition of the transcription factor Trps1 led to repression of MDR1/P-gp while its overexpression resulted in upregulation of MDR1/P-gp. Flow cytometric analysis suggested Trps1 increased the release of several anti-cancer drugs, thus decreasing their accumulation. Immunohistochemical analysis of clinical samples indicated that the expression of Trps1 directly correlated with MDR1/P-gp. Trps1 inhibited TGFbeta-1 and directly bound to the MDR1 promoter. Our data demonstrate a role for Trps1 in the regulation of MDR1 expression in osteosarcoma.