AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/a...AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a pot展开更多
Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-b...Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-binding cassette(ABC) transporters,which can increase efflux of drugs from cancer cells,thereby decreasing intracellular drug concentration.Modulators of ABC transporters have the potential to augment the efficacy of anticancer drugs.This editorial highlights some major findings related to ABC transporters and current strategies to overcome MDR.展开更多
BACKGROUND: Cholecyst cholesterol lithiasis is a common disease of the digestive system; however, the cause of lithogenesis is still unclear. Although bile salt export pump (BSEP), multidrug resistance protein 2 (MRP2...BACKGROUND: Cholecyst cholesterol lithiasis is a common disease of the digestive system; however, the cause of lithogenesis is still unclear. Although bile salt export pump (BSEP), multidrug resistance protein 2 (MRP2), and multiple drug resistance 3 (MDR3 ) are 3 well-known transporting proteins, their effect on lithogenesis has not been elucidated. This study was undertaken to examine the relationship between BSEP, MRP2, MDR3, and cholesterol calculus formation. METHODS: Liver tissue specimens were taken from 20 patients with cholesterol calculus and from 10 patients with normal liver. mRNA and protein expressions of BSEP, MRP2, and MDR3 were determined by reverse tran-scriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively. This study was approved by the ethics committee of China Medical University and informed consent was obtained from all patients. RESULTS: mRNA and protein expressions of BSEP, MRP2, and MDR3 were significantly down-regulated in the liver tissue of the patients with cholesterol calculus compared with normal liver tissue of the controls. CONCLUSION: The down-regulation of BSEP, MRP2, and MDR3 may be correlated with the formation of cholesterol calculus.展开更多
药物外排转运蛋白对药代动力学参数变化起着关键性作用。近年来研究较多的外排型转运蛋白除了P-糖蛋白(P-glycoprotein,P-gp)、乳腺癌耐药蛋白(breast cancer resistance protein,BCRP)外,多药耐药相关蛋白2(multidrug resistance prote...药物外排转运蛋白对药代动力学参数变化起着关键性作用。近年来研究较多的外排型转运蛋白除了P-糖蛋白(P-glycoprotein,P-gp)、乳腺癌耐药蛋白(breast cancer resistance protein,BCRP)外,多药耐药相关蛋白2(multidrug resistance protein 2,MRP2)逐渐成为了研究的热点。肿瘤微缺氧环境中一些信号转导通路、转录因子参与MRP2基因的表达调控,这些因子包括过氧化物酶体增殖剂激活受体(peroxisome proliferators-activated receptors,PPARα)、核因子-κB(nuclear factorκB,NF-κB)、孕烷X受体(pregnane X receptor,PXR)、法尼醇X受体(farnesoid X receptor,FXR)、组成型雄烷受体(constitutive androstane receptor,CAR)和micro RNA等,但MRP2在缺氧条件下的调控机制尚不完全清楚,且是一个很复杂的过程。MRP2作为最主要的外排转运蛋白之一,多种常用药物及抑制剂是其底物,MRP2的表达变化会显著影响这些底物药代动力学(吸收、分布、代谢、排泄)。同时,缺氧状态下MRP2不仅是由单一的信号通路或者某个转录基因调控,而是涉及多个信号通路以及诸多基因,从而构成一个调控网络。展开更多
Quercetin is a biologically active flavonoid that has been used as a popular health supplement.It is reported that quercetin may cause flavonoid-drug interaction mediated by P-glycoprotein,the most predominant efflux ...Quercetin is a biologically active flavonoid that has been used as a popular health supplement.It is reported that quercetin may cause flavonoid-drug interaction mediated by P-glycoprotein,the most predominant efflux transporter.In this study,we comprehensively evaluated the potential of the pharmacokinetic interaction of quercetin mediated by multidrug resistance-associated protein 2(MRP2),another major efflux transporter.MRP2-transfected MDCKII cells and LS174T cells were used to evaluate the potential inhibition and induction of MRP2 by quercetin in vitro.To evaluate the induction effect of quercetin on Mrp2 in vivo,Mrp2 mRNA expression in rat liver,kidney,and small intestinal tissues was determined after the oral administration of quercetin(50,100,or 250 mg/kg)for seven days.Mrp2-mediated interaction potential was also evaluated by the pharmacokinetic study of phenolsulfonphthalein in rats after single or multiple doses of quercetin.Additionally,the effect of quercetin on absorption of docetaxel,a P-glycoprotein and CYP3A4 substrate,was also evaluated.Quercetin inhibited the function of MRP2 at 10μM and induced the mRNA expression of MRP2 at 50μM in vitro.Additionally,at 100 mg/kg,quercetin markedly increased Mrp2 expression in the small intestine of rats.However,there was no significant change in phenolsulfonphthalein pharmacokinetics due to single-(50,100,or 250 mg/kg)or multiple-dose(50,100,or 250 mg/kg for seven days)quercetin co-administration.By contrast,a significant interaction caused by quercetin(100 mg/kg)was observed in the absorption of docetaxel.The results suggested that although quercetin modulates the function and expression of MRP2 in vitro,it may have a low potential of Mrp2-mediated interaction and present negligible safety concerns related to the interaction.展开更多
BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK...BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.展开更多
目的利福平(Rifampicin,RIF)具有肝毒性,但其机制尚不清楚。本研究在RIF诱导的肝内胆汁淤积小鼠中,探讨RIF对肝细胞胆汁酸转运体胆汁酸输出泵(bile salt exportpump,Bsep)和多药抵抗相关蛋白-2(multidrug resistance-associated protein...目的利福平(Rifampicin,RIF)具有肝毒性,但其机制尚不清楚。本研究在RIF诱导的肝内胆汁淤积小鼠中,探讨RIF对肝细胞胆汁酸转运体胆汁酸输出泵(bile salt exportpump,Bsep)和多药抵抗相关蛋白-2(multidrug resistance-associated protein-2,Mrp2)表达和定位影响。方法 48只♀ICR小鼠随机分为4组,RIF1wk组:经灌胃给予RIF(200mg.kg-1.d-1),连续1周,于末次给药后6h取材;RIF6h组:单次灌胃给予RIF(200mg.kg-1)后6h取材;RIF1周对照组(CON1wk)与RIF6h对照组(CON6h):经灌胃给予等容积生理盐水。所有小鼠均收集血液和肝组织,常规生化检测血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、碱性磷酸酶(ALP)、总胆红素(TB)和结合胆红素(DB),并检测小鼠血清和肝组织总胆汁酸(TBA)水平。HE染色分析肝组织病理改变。RT-PCR测定肝脏肝细胞胆汁酸转运体Bsep和Mrp2mRNA表达。免疫荧光法分析Bsep和Mrp2在肝细胞的位置。结果给予RIF1周后,小鼠血清TB由(1.25±0.69)μmol.L-1上升至(65.73±12.08)μmol.L-1,上升近70倍,DB由(0.77±0.40)μmol.L-1上升至(53.33±12.43)μmol.L-1,上升约80倍,ALP由(110.2±13.8)U.L-1上升至(279.5±80.4)U.L-1,上升约1.5倍,TBA由(3.15±0.89)μmol.L-1上升至(13.54±6.51)μmol.L-1,上升约5倍并伴有血清ALT和AST轻度升高;肝脏组织TBA由(0.15±0.04)μmol.g-1liver上升至(0.30±0.19)μmol.g-1liver,上升约2倍;肝脏组织HE染色显示肝细胞出现脂肪变性、轻度坏死和炎症。单次给予RIF6h后血清TB、DB、ALP、ALT、AST和TBA明显上升,但未观察到小鼠肝脏组织病理发生改变。免疫荧光分析显示,给予小鼠RIF1wk与单次给予RIF6h后肝细胞中Bsep和Mrp2的定位发生了改变。而无论单次给予RIF还是连续给药1周,肝细胞Bsep和Mrp2mRNA表达水平均未发生变化。结论肝细胞胆汁酸转运体Bsep和Mrp2定位改变可能是RIF诱发肝内胆汁淤积的重要机制。展开更多
基金Supported by Innovation Fund of Fujian Province,No.2007-CXB-7Key Science and Technology Project of Xiamen,No.3502Z20077045
文摘AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a pot
基金supported by funds from NIH R15 No. 1R15CA143701 (Z.S. Chen)St.John's University Seed Grant No. 579-1110 (Z.S. Chen)
文摘Multidrug resistance(MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-binding cassette(ABC) transporters,which can increase efflux of drugs from cancer cells,thereby decreasing intracellular drug concentration.Modulators of ABC transporters have the potential to augment the efficacy of anticancer drugs.This editorial highlights some major findings related to ABC transporters and current strategies to overcome MDR.
文摘BACKGROUND: Cholecyst cholesterol lithiasis is a common disease of the digestive system; however, the cause of lithogenesis is still unclear. Although bile salt export pump (BSEP), multidrug resistance protein 2 (MRP2), and multiple drug resistance 3 (MDR3 ) are 3 well-known transporting proteins, their effect on lithogenesis has not been elucidated. This study was undertaken to examine the relationship between BSEP, MRP2, MDR3, and cholesterol calculus formation. METHODS: Liver tissue specimens were taken from 20 patients with cholesterol calculus and from 10 patients with normal liver. mRNA and protein expressions of BSEP, MRP2, and MDR3 were determined by reverse tran-scriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively. This study was approved by the ethics committee of China Medical University and informed consent was obtained from all patients. RESULTS: mRNA and protein expressions of BSEP, MRP2, and MDR3 were significantly down-regulated in the liver tissue of the patients with cholesterol calculus compared with normal liver tissue of the controls. CONCLUSION: The down-regulation of BSEP, MRP2, and MDR3 may be correlated with the formation of cholesterol calculus.
文摘药物外排转运蛋白对药代动力学参数变化起着关键性作用。近年来研究较多的外排型转运蛋白除了P-糖蛋白(P-glycoprotein,P-gp)、乳腺癌耐药蛋白(breast cancer resistance protein,BCRP)外,多药耐药相关蛋白2(multidrug resistance protein 2,MRP2)逐渐成为了研究的热点。肿瘤微缺氧环境中一些信号转导通路、转录因子参与MRP2基因的表达调控,这些因子包括过氧化物酶体增殖剂激活受体(peroxisome proliferators-activated receptors,PPARα)、核因子-κB(nuclear factorκB,NF-κB)、孕烷X受体(pregnane X receptor,PXR)、法尼醇X受体(farnesoid X receptor,FXR)、组成型雄烷受体(constitutive androstane receptor,CAR)和micro RNA等,但MRP2在缺氧条件下的调控机制尚不完全清楚,且是一个很复杂的过程。MRP2作为最主要的外排转运蛋白之一,多种常用药物及抑制剂是其底物,MRP2的表达变化会显著影响这些底物药代动力学(吸收、分布、代谢、排泄)。同时,缺氧状态下MRP2不仅是由单一的信号通路或者某个转录基因调控,而是涉及多个信号通路以及诸多基因,从而构成一个调控网络。
基金supported by Basic Science Research Pro-gram through the National Research Foundation of Korea funded by the Ministry of Science,ICT and Future Planning(NRF-2015R1A2A2A01002673)
文摘Quercetin is a biologically active flavonoid that has been used as a popular health supplement.It is reported that quercetin may cause flavonoid-drug interaction mediated by P-glycoprotein,the most predominant efflux transporter.In this study,we comprehensively evaluated the potential of the pharmacokinetic interaction of quercetin mediated by multidrug resistance-associated protein 2(MRP2),another major efflux transporter.MRP2-transfected MDCKII cells and LS174T cells were used to evaluate the potential inhibition and induction of MRP2 by quercetin in vitro.To evaluate the induction effect of quercetin on Mrp2 in vivo,Mrp2 mRNA expression in rat liver,kidney,and small intestinal tissues was determined after the oral administration of quercetin(50,100,or 250 mg/kg)for seven days.Mrp2-mediated interaction potential was also evaluated by the pharmacokinetic study of phenolsulfonphthalein in rats after single or multiple doses of quercetin.Additionally,the effect of quercetin on absorption of docetaxel,a P-glycoprotein and CYP3A4 substrate,was also evaluated.Quercetin inhibited the function of MRP2 at 10μM and induced the mRNA expression of MRP2 at 50μM in vitro.Additionally,at 100 mg/kg,quercetin markedly increased Mrp2 expression in the small intestine of rats.However,there was no significant change in phenolsulfonphthalein pharmacokinetics due to single-(50,100,or 250 mg/kg)or multiple-dose(50,100,or 250 mg/kg for seven days)quercetin co-administration.By contrast,a significant interaction caused by quercetin(100 mg/kg)was observed in the absorption of docetaxel.The results suggested that although quercetin modulates the function and expression of MRP2 in vitro,it may have a low potential of Mrp2-mediated interaction and present negligible safety concerns related to the interaction.
基金supported by grants from the Medical Innovation Fundation of Fujian Province(No.2007-CXB-7)the Natural Science Foundation of Fujian Province(No.2009D010)
文摘BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.
