Multidrug resistance （MDR） in tumor cells can reduce the efficacy of chemotherapy. Overexpression of transporters is an important mechanism for MDR. P-glycoprotein （P-gp） is an ATP-binding cassette transporter frequently expressed in multidrug resistant tumor cells, inducing MDR. To reverse P-gp dependent MDR, anticancer drugs can be administered with P-gp inhibitors. Piperine and （R）-（＋）-citronellal both are P-gp inhibitors from dietary sources. In the present study, we aimed to evaluate the MDR reversal effects of piperine and （R）-（＋）-citronellal in multidrug resistant MCF-7/DOX cells. The results of cytotoxicity studies indicated that piperine and （R）-（＋）-citronellal both could abate the resistance of MCF-7/DOX after 72-h incubation. After 72-h incubation, piperine could dose-dependently down-regulate the MDR1 expression at the mRNA level, while （R）-（＋）-citronellal had no effect on the MDR1 expression. Therefore, piperine and （R）-（＋）-citronellal both could reverse MDR in MCF-7/DOX cells, and the reversal effect ofpiperine was related to dose-dependent down-regulation of the MDR1 expression at the mRNA level.
研究治疗胎儿快速性心律失常的一系列药物在过表达乳腺癌耐药蛋白(breast cancer resistance protein,BCRP)的马丁达比犬肾上皮细胞系MDCKII-BCRP单层细胞模型中的跨膜转运机制,筛选BCRP底物。利用MDCKII-BCRP和MDCKII单层细胞模型研究索他洛尔(sotalol)、普萘洛尔(propranolol)、普罗帕酮(propafenone)、普鲁卡因胺(procainamide)及氟卡尼(flecainide)的双向转运特性,采用HPLC或化学发光仪测定药物含量,计算其表观渗透系数(Papp)、外排率(RE)和净外排率(Rnet),将Rnet>1.5的药物进行细胞蓄积实验,考察药物浓度和BCRP抑制剂槲皮素对该药细胞内蓄积的影响。所选择的药物中,索他洛尔、普萘洛尔、普罗帕酮和普鲁卡因胺在两种细胞单层顶侧(apical,A)→基底侧(basolateral,B)的转运与B→A的转运之间无显著性差异,Rnet均小于1.5;氟卡尼浓度为20和5μmol·L-1时,Rnet分别为1.6和1.9。细胞蓄积实验证实氟卡尼在MDCKII、MDCKIIBCRP细胞内蓄积具有浓度依赖性,且MDCKII-BCRP细胞内的蓄积量明显低于MDCKII细胞;当同时在MDCKII-BCRP细胞内加入50μmol·L-1槲皮素时,氟卡尼在细胞中的蓄积量显著增加(P<0.05)。结果初步提示,索他洛尔、普萘洛尔、普罗帕酮和普鲁卡因胺可能不是BCRP底物;而氟卡尼可能是BCRP底物,因此母体用该药治疗胎儿快速性心律失常时,母体胎盘滋养层细胞膜上表达的BCRP极有可能会介导其外排,从而显著影响治疗效果。
