目的探讨胆汁酸盐输出泵(bile salt export pump,BSEP)、多药耐药相关蛋白2(multidrug resistant protein 2,MRP2)和多药耐药糖蛋白3(multidrug resistance associated protein 3,MDR3)在原发性胆汁性胆管炎(primary biliary cholangiti...目的探讨胆汁酸盐输出泵(bile salt export pump,BSEP)、多药耐药相关蛋白2(multidrug resistant protein 2,MRP2)和多药耐药糖蛋白3(multidrug resistance associated protein 3,MDR3)在原发性胆汁性胆管炎(primary biliary cholangitis,PBC)患者肝组织中的表达特点。方法收集2009年1月至2019年12月于南昌市第九医院住院且经肝组织病理诊断为PBC的46例患者临床资料,根据PBC严重程度分为PBC早期组(Ⅰ~Ⅱ期,31例)和PBC晚期组(Ⅲ~Ⅳ期,15例),比较两组患者血清丙氨酸氨基转移酶(alanine aminotransferase,ALT)、天门冬氨酸氨基转移酶(aspartate transaminase,AST)、总胆汁酸(total bile acid,TBA)、总胆红素(total bilirubin,TBil)、直接胆红素(direct bilirubin,DBil)、碱性磷酸酶(alkaline phosphatase,ALP)、γ-谷氨酰转移酶(gamma-glutamyltransferase,GGT)、高密度脂蛋白(high-density lipoprotein,HDL)、总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、低密度脂蛋白(low-density lipoprotein,LDL)等的差异。选取10例慢性乙型肝炎病毒(hepatitis B virus,HBV)携带者作为对照组。对所有入选病例肝组织进行BSEP、MDR3、MRP2免疫组织化学标记,观察各组肝组织病理形态及3种转运蛋白表达差异。结果PBC晚期组患者血清ALP(中位数:404 U/L vs 281 U/L)、GGT(中位数:437 U/L vs 245 U/L)、TC(中位数:6.58 mg/L vs 4.50 mg/L)、TG(中位数:1.72 mg/L vs 1.24 mg/L)、LDL(中位数:3.61 mg/L vs 2.27 mg/L)水平均显著低于PBC早期组,差异有统计学意义(P均<0.05)。两组患者年龄、性别、血清ALT、AST、TBA、TBil、DBil、HDL水平及AMA阳性率差异均无统计学意义(P均>0.05)。与PBC早期组相比,PBC晚期组患者炎症活动度和纤维化程度均较重,差异有统计学意义(χ^(2)=14.71,P=0.0006;χ^(2)=20.57,P<0.001)。PBC早期组与PBC晚期组患者肝细胞CK7和CK19染色阳性率无统计学差异[54.84%(17/31)vs 46.67%(7/15),χ^(2)=0.271、P=0.755;74.19%(23/31)vs 86.67%(13/15),连续校正χ^(2)=0.337、P=0.562]。PBC组患者肝组织中BSEP高表达率显著低于对照组[54.76%(23/42)vs 100.00%(10/10);χ^(2)=5.311,P=0.021],MDR3和MRP2高表达率差异无统计学意义[91.18%(31/34)vs 100.00%(10/10),P=1.000;69.7%(23/33)vs 100.00%(10/10);χ^(2)=2.433,P=0.119]。PBC晚期组患者BSEP高表达率显著低于PBC早期组[68.97%(20/29)vs 23.08%(3/13);χ^(2)=7.630,P=0.008],MDR3和MRP2阳性高表达率差异无统计学意义[91.30%(21/23)vs 90.91%(10/11),P=1.000;68.18%(15/22)vs 72.73%(8/11),P=1.000]。BSEP、MRP2、MDR3在胆汁淤积区阳性表达减少越显著,肝细胞胆汁淤积肿胀及羽毛样变性越明显。结论BSEP在PBC患者肝组织中表达降低,且在PBC晚期组患者肝组织表达率显著降低,提示PBC胆汁淤积与毛细胆管膜侧BSEP蛋白表达缺陷有关,并且PBC疾病进展可能与BSEP表达减少有关。展开更多
Mutations of the bile salt export pump (BSEP) or the multidrug resistance P-glycoprotein 3 (MDR3) are linked to impaired bile salt homeostasis and lead to progressive familial intrahepatic cholestasis (PFIC)-2 and -3,...Mutations of the bile salt export pump (BSEP) or the multidrug resistance P-glycoprotein 3 (MDR3) are linked to impaired bile salt homeostasis and lead to progressive familial intrahepatic cholestasis (PFIC)-2 and -3, respectively. The regulation of bile salt transporters in PFIC is not known. Expression of hepatobiliary transporters in livers of ten patients with a PFIC phenotype was studied by quantitative reverse transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy. PFIC was diagnosed by clinical and laboratory findings. All patients could be assigned to PFIC-2 or PFIC-3 by the use of BSEP-and MDR3-specific antibodies and by MDR3 gene-sequencing. Whereas in all PFIC-2 patients, BSEP immunoreactivity was absent from the canalicular membrane, in three PFIC-3 livers, canalicular MDR3 immunoreactivity was detectable. Serum bile salts were elevated to 276 ±233 and to 221 ±109 μmol/L in PFIC-2 and PFIC-3, respectively. Organic anion transporting polypeptide OATP1B1, OATP1B3, and MRP2 mRNA and protein levels were reduced, whereas sodium taurocholate cotransporting polypeptide (NTCP) was only reduced at the protein level, suggesting a posttranscriptional NTCP regulation. Whereas MRP3 mRNA and protein were not significantly altered, MRP4 messenger RNA and protein were significantly increased in PFIC. In conclusion, PFIC-2 may be reliably diagnosed by immunofluorescence, whereas the diagnosis of PFIC-3 requires gene-sequencing. Several mechanisms may contribute to elevated plasma bile salts in PFIC: reduced bile salt uptake via NTCP, OATP1B1, and OATP1B3, decreased BSEP-dependent secretion into bile, and increased transport back into plasma by MRP4. Upregulation of MRP4, but not of MRP3, might represent an important escape mechanism for bile salt extrusion in PFIC.展开更多
The ability of two dihydrostilbene derivatives erianin and chrysotoxine from Dendrobium chrysotoxum to reverse multidrug resistant (MDR) cells was investigated using murine B16 melanoma cells transfected with the huma...The ability of two dihydrostilbene derivatives erianin and chrysotoxine from Dendrobium chrysotoxum to reverse multidrug resistant (MDR) cells was investigated using murine B16 melanoma cells transfected with the human MDR 1 gene and crossresistant to vinblastine and adriamycin (B16/h MDR 1 cells). Both of the two compounds were shown to increase the accumulation of adriamycin, the P glycoprotein (P gp) substrate, in B16/h MDR 1 transfectants.展开更多
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 potential drug target for circumventing MDR HCC cells,展开更多
A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function ...A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdrl mRNA expression by 83. 5 %; and the expressed ribozyme could inhibite the formation of p-glycoprotein detected by immuno- cy-tochemistry assay and could reduce the cell’s resistance to adrimycin; this means that the resistant cells were 1 000-fold more resistant than the parental cell line(MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.展开更多
Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism b...Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism by which cancer cells acquire high levels of P-gp has not been well defined. Accumulating evidence suggests that nuclear receptors （NRs）, especially human pregnane X receptor （PXR）, play a crucial role in multidrug resistance. It has been shown that chemotherapeutic drug activates PXR and then enhances P-gp expression. Genetic knockdown or pharmacologic inhibition of PXR led to attenuation of drug-induced MDR1 over expression, implying that NRs may be an effective target to reverse multidrug resistance. Recent investigations suggested that transcriptional activity of NRs is mediated by methylases, the important enzymes involved in epigenetic regulation. Other epigenetic modifications, such as promoter methylation, histone deacetylases and microRNAs, were also found to be involved in activation of MDR1 promoter, though the underlying mechanisms are not thoroughly known. In this review, we summarized recent researches in the regulation of P-gp expression, with particular focus on NRs and epigenetics, aiming to provide references and options to reverse and/or prevent MDR in cancer treatment.展开更多
Chemotherapy-induced multi-drug resistance(MDR) in tumors poses a huge challenge for clinical treatment of tumors. The downregulation of the multi-drug resistance relative protein, represented by P-glycoprotein(P-gp),...Chemotherapy-induced multi-drug resistance(MDR) in tumors poses a huge challenge for clinical treatment of tumors. The downregulation of the multi-drug resistance relative protein, represented by P-glycoprotein(P-gp), can reverse MDR of cancer cells. In this study, we developed doxorubicin-loading nanocarrier based on the assembly of protein and antisense oligonucleotide(ASO) to combat MDR of cancer cells. The data demonstrate that the nanocarrier can efficiently deliver ASO to cytoplasm and downregulate the P-glycoprotein expression, subsequently improving the therapeutic effects of Dox in doxorubicin-resistant MCF-7/ADR cancer cells. The preparation is simple and effective, providing a powerful tool for gene delivery. Therefore, our nanocarrier shows high promise in cancer treatment.展开更多
Cancer is still one of the important diseases that threatens the health of people. Multidrug resistance(MDR) is the main factor that leads to the failure of cancer chemotherapy. Thus, MDR diagnosis could facilitate th...Cancer is still one of the important diseases that threatens the health of people. Multidrug resistance(MDR) is the main factor that leads to the failure of cancer chemotherapy. Thus, MDR diagnosis could facilitate the monitoring of the therapy process and realization of efficient treatment of tumors. In this study, we have tried to use a new tetrathiafulvalene(TTF) derivative(TTF-(COONBu4)2) to sensitively recognize the MDR through the multi-signal responsive strategy. The relevant electrochemical and spectroscopic studies demonstrate the specific binding behavior of TTF-(COONBu4)2 with P-glycoprotein(P-gp) as well as drug-resistant leukemia cells. Especially due to the over-expression of specific components of P-gp on the plasma membranes of drug resistant cells, the electrochemical and hydrophilic/hydrophobic features of drug resistant-leukemia cells are apparently different from those of other kinds of leukemia cells. Meanwhile, Fourier transform infrared spectroscopic study illustrates that the most intense vibration band of TTF moieties in the 1400–1600 cm-1 range is almost smeared out upon binding to P-gp, and the binding of TTF-(COONBu4)2 to P-gp may also lead to changes in protein secondary structure and backbone. This observation may advance the development of the new TTF agent for the promising clinical diagnosis and monitoring of MDR of tumors with the aim of successful chemotherapy for human cancer.展开更多
文摘Mutations of the bile salt export pump (BSEP) or the multidrug resistance P-glycoprotein 3 (MDR3) are linked to impaired bile salt homeostasis and lead to progressive familial intrahepatic cholestasis (PFIC)-2 and -3, respectively. The regulation of bile salt transporters in PFIC is not known. Expression of hepatobiliary transporters in livers of ten patients with a PFIC phenotype was studied by quantitative reverse transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy. PFIC was diagnosed by clinical and laboratory findings. All patients could be assigned to PFIC-2 or PFIC-3 by the use of BSEP-and MDR3-specific antibodies and by MDR3 gene-sequencing. Whereas in all PFIC-2 patients, BSEP immunoreactivity was absent from the canalicular membrane, in three PFIC-3 livers, canalicular MDR3 immunoreactivity was detectable. Serum bile salts were elevated to 276 ±233 and to 221 ±109 μmol/L in PFIC-2 and PFIC-3, respectively. Organic anion transporting polypeptide OATP1B1, OATP1B3, and MRP2 mRNA and protein levels were reduced, whereas sodium taurocholate cotransporting polypeptide (NTCP) was only reduced at the protein level, suggesting a posttranscriptional NTCP regulation. Whereas MRP3 mRNA and protein were not significantly altered, MRP4 messenger RNA and protein were significantly increased in PFIC. In conclusion, PFIC-2 may be reliably diagnosed by immunofluorescence, whereas the diagnosis of PFIC-3 requires gene-sequencing. Several mechanisms may contribute to elevated plasma bile salts in PFIC: reduced bile salt uptake via NTCP, OATP1B1, and OATP1B3, decreased BSEP-dependent secretion into bile, and increased transport back into plasma by MRP4. Upregulation of MRP4, but not of MRP3, might represent an important escape mechanism for bile salt extrusion in PFIC.
文摘The ability of two dihydrostilbene derivatives erianin and chrysotoxine from Dendrobium chrysotoxum to reverse multidrug resistant (MDR) cells was investigated using murine B16 melanoma cells transfected with the human MDR 1 gene and crossresistant to vinblastine and adriamycin (B16/h MDR 1 cells). Both of the two compounds were shown to increase the accumulation of adriamycin, the P glycoprotein (P gp) substrate, in B16/h MDR 1 transfectants.
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 potential drug target for circumventing MDR HCC cells,
基金This research was supported by the National Natural ScienceYouth Grant.
文摘A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdrl mRNA expression by 83. 5 %; and the expressed ribozyme could inhibite the formation of p-glycoprotein detected by immuno- cy-tochemistry assay and could reduce the cell’s resistance to adrimycin; this means that the resistant cells were 1 000-fold more resistant than the parental cell line(MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.
文摘Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism by which cancer cells acquire high levels of P-gp has not been well defined. Accumulating evidence suggests that nuclear receptors （NRs）, especially human pregnane X receptor （PXR）, play a crucial role in multidrug resistance. It has been shown that chemotherapeutic drug activates PXR and then enhances P-gp expression. Genetic knockdown or pharmacologic inhibition of PXR led to attenuation of drug-induced MDR1 over expression, implying that NRs may be an effective target to reverse multidrug resistance. Recent investigations suggested that transcriptional activity of NRs is mediated by methylases, the important enzymes involved in epigenetic regulation. Other epigenetic modifications, such as promoter methylation, histone deacetylases and microRNAs, were also found to be involved in activation of MDR1 promoter, though the underlying mechanisms are not thoroughly known. In this review, we summarized recent researches in the regulation of P-gp expression, with particular focus on NRs and epigenetics, aiming to provide references and options to reverse and/or prevent MDR in cancer treatment.
基金supported by the National Natural Science Foundation of China (21325520, 21327009, 21405041, J1210040)the Foundation for Innovative Research Groups of National Natural Science Foundation of China (21521063)the Science and Technology Project of Hunan Province (2016RS2009, 2016WK2002)
文摘Chemotherapy-induced multi-drug resistance(MDR) in tumors poses a huge challenge for clinical treatment of tumors. The downregulation of the multi-drug resistance relative protein, represented by P-glycoprotein(P-gp), can reverse MDR of cancer cells. In this study, we developed doxorubicin-loading nanocarrier based on the assembly of protein and antisense oligonucleotide(ASO) to combat MDR of cancer cells. The data demonstrate that the nanocarrier can efficiently deliver ASO to cytoplasm and downregulate the P-glycoprotein expression, subsequently improving the therapeutic effects of Dox in doxorubicin-resistant MCF-7/ADR cancer cells. The preparation is simple and effective, providing a powerful tool for gene delivery. Therefore, our nanocarrier shows high promise in cancer treatment.
基金supported by the National Natural Science Foundation of China(81325011)the National High Technology Research&Development Program of China(2012AA022703)+1 种基金the National Basic Research Program of China(2010CB732404)the Major Science&Technology Project of Suzhou(ZXY2012028)
文摘Cancer is still one of the important diseases that threatens the health of people. Multidrug resistance(MDR) is the main factor that leads to the failure of cancer chemotherapy. Thus, MDR diagnosis could facilitate the monitoring of the therapy process and realization of efficient treatment of tumors. In this study, we have tried to use a new tetrathiafulvalene(TTF) derivative(TTF-(COONBu4)2) to sensitively recognize the MDR through the multi-signal responsive strategy. The relevant electrochemical and spectroscopic studies demonstrate the specific binding behavior of TTF-(COONBu4)2 with P-glycoprotein(P-gp) as well as drug-resistant leukemia cells. Especially due to the over-expression of specific components of P-gp on the plasma membranes of drug resistant cells, the electrochemical and hydrophilic/hydrophobic features of drug resistant-leukemia cells are apparently different from those of other kinds of leukemia cells. Meanwhile, Fourier transform infrared spectroscopic study illustrates that the most intense vibration band of TTF moieties in the 1400–1600 cm-1 range is almost smeared out upon binding to P-gp, and the binding of TTF-(COONBu4)2 to P-gp may also lead to changes in protein secondary structure and backbone. This observation may advance the development of the new TTF agent for the promising clinical diagnosis and monitoring of MDR of tumors with the aim of successful chemotherapy for human cancer.
