The Effect Of Mifepristone On Adriamycin Resistance Of MCF-7/ADM Cell Line In Human Breast Cancer Xenograft Of Nude Mice

Obejective: To study the effect of mifepristone on adriamycin resistance of MCF-7/ADM cell line in human breast cancer xenograft of nude mice.Methods: Culturede adriamycin resistance cell of human breast cancer MCF-7/ADM. Established adriamycin resistance human breast cancer models that xenofraft transplanted subcutaneous in nude mice. Randomized the mice into 4 groups: control group, mifepristoneon group (MIF group), adriamycin group(ADM group), adriamycin+mifepristone group(ADM+MIF group) . After the models were established, different treatment were given respectively: control group was treated with saline water 0.2ml intraperitoneally and edible oil 0.5ml orally, mifepristone group was treated with mifepristone 30mg/kg orally and saline water 0.2ml intraperitoneally, adriamycin group was treated with adriamycin 5mg/kg intraperitoneally and edible oil 0.5ml orally, mifepristone combined with adriamycin group was treated with adriamycin 5mg/kg intraperitoneally and mifepristone 30mg/kg orally every three day. The tumor growth was monitored from the first day of treatment, the long diameter and short diameter of the xenograft were measured before treatment every three day, volumes were calculate and growth curve was drawn and the weight of mice before and after treatment was recorded. The mice were sacrificed on the 28^th day. Every xenograft was cut down and weighed. Haematoxylin-eosin staining for xenofraft tissue was performed. The pathomorphism of xenofraft was observed.Results: Except mifepristone group(778.2846±42.6919mm3), the xenograft volume of both adriamycin group(508.9648±16.2609 mm3) and mifepristone+adriamycin group(232.5149±309.2377mm3) was smaller than that of control group(962.2309±261.1313 mm3) after the 4 weeks' treatment, with statistical significance(P<0.05). The xenograft volume of mifepristoneon+adriamycin group was smaller than that of mifepristone group and adriamycin group, both with statistical significance(P<0.05). Except mifepristone group(0.76±0.47g), the xenograft weight of both adriamycin group(0.48±0.17g) and adriamycin+mifepristone group (0.20±0.38g) was lower than that of control group(0.91±0.23g), with statistical significance(P<0.05). The xenograft weight of adriamycin +mifepristone group was lower than that of mifepristone group and adriamycin group, both with statistical significance(P<0.05).Conclusions:1. Establishment of adriamycin resistance human breast cancer models in nude mice successfully provides a study platform for human breast cancer resistant to adriamycin.2. The resistant effect of human breast cancer cell to adriamycin MCF-7/ADM xenograft can be reversed by mifepristone in vivo.