The present invention relates to a new use of a known medicament. Specifically, the invention relates to methods and compositions for enhancing the therapeutic efficacy of a therapeutic agent by increasing the uptake of the therapeutic agent by target cells, and in particular relates to a pharmaceutical composition comprising a regulating agent of lipid raft/caveolae-dependent endocytic pathway and some therapeutic agents, such as anti-tumor agents. The invention also relates to a method for screening a regulating agent of lipid raft/caveolae-dependent endocytic pathway capable of enhancing the therapeutic efficacy of anti-tumor agents.