Thymidine phosphorylase is regulated by tamoxifen in T47D breast cancer cell line

Background: Thymidine phosphorylase (TP) has diverse functions within cells, including increasing the sensitivity of cancer cells to cytotoxic drugs including 5-fluorouracil (5-FU) and methotrexate. However, the regulators of TP still remains largely unknown. Method: In this study, we examined whether tamoxifen has specific effects on TP expression in the T47D breast cancer cell line. We studied the TP expression in the T47D cell line before and after tamoxifen treatment using Western blot analysis and ELISA. Results: We found that TP expression is significantly up-regulated in tamoxifen-treated cells compared with control. Conclusions: Our findings suggest that tamoxifen may increase chemotherapy sensitivity through TP up-regulation for treatment regimens including doxifluridine, capecitabine, and/or methotrexate.