However , dipyridamole had no effect on both the influx and efflux of epirubicin in doxorubicin-sensitive cells .
[Studies on reversing effect of multidrug resistance by dipyridamole. II. Inhibition of epirubicin efflux from resistant cells by dipyridamole and its pharmacological effect]. We have previously reported that dipyridamole increases the cytotoxicity of epirubicin and alters the cell cycle in doxorubicin-resistant (P388/DOX) cells, increasing the accumulation of G2/M phase by blocking the cell cycle. In cultured cells, dipyridamole increased dose-dependently the intracellular accumulation of epirubicin in the resistant cells. Simultaneous exposure of the resistant cells to epirubicin and 100 microM dipyridamole resulted in a 4.2-fold increase in proportion to the control level of epirubicin after 60 min. dipyridamole inhibited the enhanced efflux of epirubicin in doxorubicin-resistant cells. However , dipyridamole had no effect on both the influx and efflux of epirubicin in doxorubicin-sensitive cells . In mice, lethal and bone marrow toxicity induced by epirubicin were potentiated by administration of high-dose of dipyridamole. In addition, in vivo results also demonstrated that dipyridamole in combination with epirubicin produced a significant reversal of the in vivo antitumor activity of epirubicin in mice bearing P388/DOX cells. These data imply the enhancement effects of dipyridamole on the efficacy and toxicity of epirubicin.
### Instruction:
            Given the context about compound efficacy for the given treatment mentioned within the input, mentioned the compounds 
            that can co-occur for the mentioned treatment

            ### Input:
            [Studies on reversing effect of multidrug resistance by dipyridamole. II. Inhibition of epirubicin efflux from resistant cells by dipyridamole and its pharmacological effect]. We have previously reported that dipyridamole increases the cytotoxicity of epirubicin and alters the cell cycle in doxorubicin-resistant (P388/DOX) cells, increasing the accumulation of G2/M phase by blocking the cell cycle. In cultured cells, dipyridamole increased dose-dependently the intracellular accumulation of epirubicin in the resistant cells. Simultaneous exposure of the resistant cells to epirubicin and 100 microM dipyridamole resulted in a 4.2-fold increase in proportion to the control level of epirubicin after 60 min. dipyridamole inhibited the enhanced efflux of epirubicin in doxorubicin-resistant cells. However , dipyridamole had no effect on both the influx and efflux of epirubicin in doxorubicin-sensitive cells . In mice, lethal and bone marrow toxicity induced by epirubicin were potentiated by administration of high-dose of dipyridamole. In addition, in vivo results also demonstrated that dipyridamole in combination with epirubicin produced a significant reversal of the in vivo antitumor activity of epirubicin in mice bearing P388/DOX cells. These data imply the enhancement effects of dipyridamole on the efficacy and toxicity of epirubicin.

            ### Response:
            dipyridamole, epirubicin
            