Mifepristone对卵巢癌细胞的单己糖神经酰胺表达及耐药性的影响(英文)

MIFEPRISTONE REVERSES DRUG RESISTANCE TO CISPLATIN IN OVARIAN CELL LINE COC1/DDP BY INHIBITING CERAMIDE MONOHEXOSIDE

目的:研究单己糖神经酰胺在卵巢癌耐药细胞株COCl/DDP对顺铂耐药性中的作用,探索mifepristone对COCl/DDP细胞耐药性逆转的机制。方法:将耐药细胞分为顺铂组、顺铂+mifepristone组,MTT方法检测各组细胞抑制率;采用改良的Hahomori方法分别提取、纯化耐药细胞COCl/DDP(用mifepristone处理前后)和敏感细胞COCI的中性鞘糖脂,高效薄层层析、凝胶先密度成像系统分析各组CMH的差异:将耐药细胞分为三组:顺铂组、mifepristone组、顺铂+mifepristone组,用透射电镜观察各组细胞的超微形态结构变化。结果:mifepristone可以逆转COCl/DDP细胞对顺铂的耐药性,1.25μmol/L的mifepristone与浓度为(0.1-1.25)μg/ml的顺铂联合应用,使细胞的抑制率从单用上述浓度顺铂时的(8.84±6.29)％-(17.71±8.00)％上升为(15.26±6.75)％-(27.15±7.69)％(P<0.001),且有剂量依赖性。耐药细胞的CMH表达率为(37.14±3.34)％,明显高于敏感细胞的(14.05±1.44)％(P<0.001),耐药细胞经1.25μmol/L、5μmol/L mifepristone处理后,CMH分别下降到(26.62±2.63)％(P<0.05)和(17.50±0.67)％(P<0.001)。顺铂和mifepristone联合作用,透射电镜观察到耐药细胞出现异染色质浓缩、边聚,产生了凋亡小体。

Objective:To investigate the effect of ceramide monohexoside(CMH)on resistance to cisplatin and the mechanism of mifepristone reversing the durg resistance in ovarian cell line COC1/DDP. Methods:COC1/DDP cells were incubated with cisplatin or both mifepristone and cisplatin, the inhibition rate of cells was evaluated by MTT (the tetrazolium dye) assay. COC1 cells and COC1/DDP cells (before and after the treatment of mifepristone) were collected and N - GSLs (neutral glycosphingolipids) of the cells were isolated and purified with the modified Hakomori's method, changes of CMH content were analyzed by HPTLC (high performance thin layer chro-matography). The forms of COC1/DDP cells incubated with mifepristone, cisplatin, mifepristone and cisplatin were observed by transmission electron microscope (TEM). Results: Mi fepristone increased the sensitivity of the COC1/ DDP cell to cisplatin 1.25μmol/L mifepristone combined with (0.1- 1.25)μg/ml cisplatin, increased the inhibition rate of COCl/DDP from(8.84±6.29)% - (17.71 ±8.00)% to (15.26 ± 6.75)% -(27.15±7.69)% (P< 0.001); 5μmol/L mifepristone combined with the privous dose of cisplatin, increased the inhibition rate of COCI/DDP to (27.71 ±15.92)% - (39.47±11.55)% (P<0.001) . After the combined treatment of mifepri-stone and cisplatin, the COCI/DDP cells turned round ,chromatin condensed and apoptosis body was produced. Conclusions : Mifepristone reversed the resistance of ovarian cellline COCI/DDP to cisplatin at low dose. Its mechanism may be related with inhibiting ceramide monohexoside(CMH) and inducing apoptosis.