Reversal of adriamycin resistance in ovarian carcinoma cell line by combination of verapamil and low-level ultrasound

In order to determine whether ultrasound, alone or combined with verapamil, could reverse resistance in adriamycin resistant human ovarian carcinoma cell line SKOV3/ADR in vitro, cells were subjected to a variable concentration of adriamycin. Verapamil, ultrasound exposure and both of the two were used concurrently or sequentially. Survival rates were decreased in groups in which acoustic irradiation was exerted, or verapamil pretreated and both of which applied. Intracellular adriamycin levels were high where cytotoxicity was enhanced. These results revealed that ultrasound reverse drug resistance in ovarian carcinoma cells, and synergism also existed between verapamil and acoustic exposure if administrated sequentially. These effects were ascribed to increase of intracellular adriamycin accumulation.