In vivo reversal of doxorubicin resistance by (-)-epigallocatechin gallate in a solid human carcinoma xenograft.

A human carcinoma xenograft model was established with resistant KB-A-1 cell line in order to investigate whether (-)-epigallocatechin gallte (EGCG) can reverse doxorubicin (DOX) resistance in vivo. EGCG could sensitize the tumors to DOX as indicated by a considerable reduction of tumor weights. The combination of DOX with EGCG increased the DOX concentration by 51% in the tumors, and increased DOX-induced apoptosis in the tumors compared with DOX alone. In addition, the combination schedules appeared to be well tolerated. We conclude that EGCG could chemosensitize resistant tumor cells to DOX in vivo through an increase in the accumulation of DOX in the tumors.