EXPRESSION AND CLINICAL SIGNIFICANCE OF MULTIDRUG RESISTANCE GENE AND MULTIDRUG RESISTANCE-ASSOCIATEDPROTEIN GENE IN ACUTE LEUKEMIA

Objective: To evaluate the expression and clinical significance of multidrug resistance gene (mdr1) and multidrug resistance-associated protein (MRP) gene in acute leukemia. Methods: The expression of mdr1 and MRP assay in 55 patients with acute leukemia (AL) by reverse transcription polymerase chain reaction (RT-PCR). Results: The mdr1 and MRP gene expression levels in the relapsed AL and the blastic plastic phases of CML were significantly higher than those in the newly diagnostic AL and controls. The mdr1 and MRP gene expression levels in the clinical drug-resistant group were significantly higher than those in the non-drug-resistant group. The complete remission (CR) rate in patients with high mdr1 expression (14.3%) was significantly lower than that with low mdr1 expression (57.5%); similarly the CR rate in patients with high MRP level was also lower than that with low MRP level. Using both high expression of mdr1 and MRP gene as the indicator for evaluating multidrug resistance (MDR), the positive predictive value and accuracy increased in comparison with single gene high expression. Conclusion: Elevated level of mdr1 or MRP gene expression might be unfavorable prognostic factors for AL patient and may be used as an important index for predicting drug-resistance and relapse in AL patient. Measuring both mdr1 and MRP gene expression would increase accuracy and sensibility of evaluating MDR in acute leukemia.

EXPRESSION OF MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN (MRP) AND ITS RELATIONSHIP WITH CLINICOPATHOLOGICAL FACTORS IN NON-SMALL CELL LUNG CANCER

Objective: To investigate the relationship between the expression of multidrug resistance-associated protein (MRP) and clinicopathological factors and prognosis. Methods: The expression of MRP in 62 cases with non-small cell lung cancer (NSCLC) was detected using immunohistochemistry method. The expression of MRP in 30 cases of NSCLC and corresponding normal lung tissues were detected using immunohistochemistry and Western Blot. Results: this study of tumor tissues confirmed the plasma membrane and/or cytoplasm locations of MRP. There was apparent difference between normal lung tissues and NSCLC in MRP. The survival analysis of 62 NSCLC showed that the mean survival time of the patients with negative MRP expression was 69.8117.41 months and that of patients with positive MRP expression, 25.384.46 months. Log-rank test suggested that the difference between them was significant (P=0.0156). It was also found that in squamous cell lung cancer the statistically significant difference between the mean survival time of patients with positive MRP expression and those with negative MRP expression (P=0.0153). Multivariate Cox model analysis suggested that the survival time was significantly related to expression of MRP (P=0.035) and lymphatic metastasis (P=0.038). Conclusion: MRP expression in NSCLC is significantly higher compared with normal lung tissues. The mean survival time of patients with negative MRP was relative longer and expression of MRP was an independent factor for prognosis.

JNK1,JNK2,and JNK3 are involved in P-glycoprotein-mediated multidrug resistance of hepatocellular carcinoma cells

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.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

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,

Expression and significance of multi-drug resistance-associated protein 3 in different tumor cell lines

Objective To investigate the expression and meaning of MRP3 in different tumor cells. MethodsThe monoclonal antibody against MRP3 was used to identify the expression of MRP3 by flow cytometer in seven tumor cells and human embryo kidney cell lines 293T.And RT-PCR was used to detect the mRNA of MRP3 in eight cell lines. ResultsThe mRNA of MRP3 was expressed in three pancreatic carcinoma cell lines.MRP3 protein was observed in BxPC-3 and AsPC-1 cells. ConclusionMRP3 may express in different tumor in tissue-specific manner.BxPC-3 and AsPC-1 may serve as cellular models for in vitro studies on multidrug resistance of pancreatic carcinoma.

Effect of Histone Deacetylase Inhibition on the Expression of Multidrug Resistance-associated Protein 2 in a Human Placental Trophoblast Cell Line

Background： Placental multidrug resistance-associated protein 2 （MRP2）, encoded by ABCC2 gene in human, plays a significant role in regulating drugs＇ transplacental transfer rates. Studies o11 placental MRP2 regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. Currently, the roles of epigenetic mechanisms in regulating placental drug transporters are still unclear. This study aimed to investigate the effect of histone deacetylases （HDACs） inhibition on MRP2 expression in the placental trophoblast cell line and to explore whether HDAC 1/2/3 are preliminarily involved in this process. Methods： The human choriocarcinoma-derived trophoblast cell line （Bewo cells） was treated with the HDAC inhibitors-trichostatin A （TSA） at different concentration gradients of 0.5, 1.0, 3.0, and 5.0 μmol/L. Cells were harvested after 24 and 48 h treatment. Small interfering RNA （siRNA） specific for HDACI/HDAC2/HDAC3 or control siRNA was transfected into cells. Total HDAC activity was detected by colorimetric assay kits. HDAC 1/2/3/ABCC2 messenger RNA （mRNA） and protein expressions were determined by real-time quantitative polymerase chain reaction and Western-blot analysis, respectively. Immunofluorescence for MRP2 protein expression was visualized and assessed using an immunofluorescence microscopy and ImageJ software, respectively. Results： TSA could inhibit total HDAC activity and HDAC 1/2/3 expression in company with increase ofM RP2 expression in Bewo cells. Reduction of HDAC 1 protein level was noted after 24 h of TSA incubation at 1.0, 3.0, and 5.0 μmol/L （vs. vehicle group, all P 〈 0.001 ）, accompanied with dose-dependent induction of MRP2 expression （P = 0.045 for 1.0 μmol/L, P = 0.001 for 3.0 μmol/L, and P 〈 0.001 for 5.0 μmol/L）, whereas no significant diferences in MRP2 expression were noted after HDAC2/3 silencing. Fluorescent micrograph images of MRP2 protein were expressed on the cell membrane. The fluorescent intensities of MRP2 in the control, HDAC2, and HDAC3 siRNA-transfected cells weir week, and no significant differences were noticed among these three groups （all P 〉 0.05）. However, MRP2 expression was remarkably elevated in H DAC1 siRNA-transfected cells, which displayed an almost 3.19-fold changes in comparison with the control siRNA-transfected cells （P 〈 0.001 ）. Conclusions： HDACs inhibition could up-regulate placental MRP2 expression in ritzy, and HDAC 1 was probably to be involved in this process.

In silico pharmacophore models to predict endogenous substrates for human multidrug resistance-associated proteins

Multidrug resistance-associated proteins （MRPs） can effiux structurally diverse drugs, drug conjugates, drug metabolites, as well as other small molecules out of the cells, and this is the main cause of producing multidrug resistance （MDR） of some anticaneer drugs. Therefore, it is crucial to uncover the molecular features of MRPs substrates in developing anti-MDR cancer therapy. In the present study, common feature pharmacophore models were developed by employing CATALYST Pharmacophore Modeling and Analysis tools using substrates of MRPs, including MRP1, -2, -3, -4, -5, -6, -8 and MRPs family, respectively. The models were validated using independent decoy sets generated in DUD-E, and the ones with best A UC （area under the curve） scores were chosen to predict endogenous substrates by screening the Human Metabolome Database （HMDB）. A number of molecules obtained by pharmacophore screening have been validated in the literatures. By comparing physical properties （ALOGP, Molecular_PolarSurfaceArea, Molecular_Volume, Molecular_Weight, Num H Acceptors, Num H Donors） and scaffold features of the screened candidates with the known substrates, we found that： 1） The two sets have consistent ALOGP, Molecule_Volume and Molecule_Weight distribution trend; 2） Substrates of MRP1 have a better lipophilicity than the other subtypes, which is consistent with the two hydrophobic centers on the MRP1 pharmacophore; 3） In the aspect of the scaffold structures, they have the identical or similar backbone fragments.

肺癌组织中耐药相关蛋白和p53 bcl-2表达及其意义

目的:探讨肺癌组织中耐药相关蛋白和p53、bcl-2表达及其意义。方法:应用免疫组化技术检测治疗前73例肺癌组织标本中P-gp、MRP、LRP、GST-π、p53和bcl-2表达。结果:非小细胞肺癌组P-gp、LRP、MRP+LRP、P-gp+p53的蛋白表达明显高于小细胞肺癌组(P<0.05)。腺癌组MRP、LRP、MRP+LRP、MRP+LRP+GST-π、MRP+LRP+P-gp+GST-π蛋白阳性表达高于鳞状细胞癌组、小细胞肺癌组(P<0.05),MRP+GST-π共表达者高于鳞状细胞癌组(P<0.01),P-gp+p53共表达者高于小细胞肺癌组(P<0.05),bcl-2蛋白阳性表达低于鳞状细胞癌组、小细胞肺癌组(P<0.05)。鳞状细胞癌组P-gp、P-gp+p53、P-gp+bcl-2的蛋白表达明显高于小细胞肺癌组(P<0.05)。P-gp与p53、bcl-2蛋白阳性表达呈正相关(P<0.05)。p53与bcl-2蛋白阳性表达呈正相关(P<0.01)。MRP与GST-π蛋白阳性表达呈正相关(P<0.05)。结论:肺癌耐药为一多途径多基因参与的过程,P-gp、LRP、MRP、GST-π、p53、bcl-2表达及其共表达可作为监测肺癌细胞原发性耐药的指标。

ABCG2食管癌耐药细胞系Eca109/ABCG2的建立

目的探讨腺苷三磷酸结合转运蛋白G超家族成员2(ABCG2)在介导食管癌多药耐药中的作用。方法扩增ABCG2基因,与pcDNA3.1载体连接,构建pcDNA3.1-ABCG2重组质粒,转染Eca109细胞后用G418筛选稳定转染细胞。采用流式细胞术检测细胞内阿霉素的含量,评价细胞对药物的外排作用。MTT法检测阿霉素对Eca109/ABCG2、Eca109/pcDNA3.1、Eca109细胞生长的抑制作用,并计算半数抑制浓度(IC50)和细胞的耐药指数。采用Western blotting和RT-PCR法检测细胞中ABCG2蛋白及mRNA的表达量。结果成功建立转染ABCG2基因的Eca109/ABCG2细胞。Eca109/ABCG2细胞中ABCG2的mRNA和蛋白表达量升高。阿霉素对Eca109/ABCG2、Eca109/pcDNA3.1、Eca109细胞的IC50值分别为18.61±3.94、4.18±0.14、4.69±0.88μg/ml。Eca109/AB-CG2细胞对阿霉素的耐药指数为3.97,且外排阿霉素的作用增强。结论Eca109/ABCG2细胞具有ABCG2的耐药表型,能够稳定表达ABCG2蛋白,可作为研究ABCG2介导的多药耐药相关机制的细胞模型。

利福平对小鼠肝细胞胆汁酸转运体Bsep和Mrp2表达与定位的影响

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。

含扶正解毒汤药血清对白血病K562/A02耐药细胞的抑制作用及初步机制

目的:探讨含扶正解毒汤药血清对白血病耐药细胞株K562/A02的抑制效果及可能的机制。方法:采用M TT法检测含扶正解毒汤药血清对K562/A02耐药细胞的生长抑制率,流式细胞技术测定含扶正解毒汤药血清处理各组K562/A02细胞后的凋亡情况,QPCR法检测BCL-2 mRNA的表达,Western blot方法检测BCL-2蛋白的表达,流式细胞技术测定细胞膜P-gp蛋白的表达。结果:MTT细胞毒实验结果表明含扶正解毒汤药血清具有抑制k562/A02细胞生长的效果,且抑制率呈药物浓度相关性;流式细胞检测结果表明含扶正解毒汤药血清可以诱导k562/A02耐药细胞的凋亡,凋亡率呈药物浓度相关性;Q-PCR结果显示,含扶正解毒汤药血清可以下调K562/A02细胞BCL-2蛋白的表达;流式细胞检测结果表明,含扶正解毒汤药血清可下调K562/A02细胞膜P-gp蛋白的表达。结论:含扶正解毒汤药血清可以促进K562/A02耐药细胞的凋亡,其诱导细胞凋亡的机制可能与抑制BCL-2蛋白和P-gp蛋白的表达有关。

P-gp、MRP、LRP、P53及c-erbB-2在非小细胞肺癌中的表达

目的:探讨P糖蛋白(P-gp)、多药耐药相关蛋白(MRP)、肺耐药蛋白(LRP)、P53蛋白及c-erbB-2蛋白在术前未经治疗的非小细胞肺癌(NSCLC)中的表达及相互间的关系。方法:采用免疫组化法检测78例NSCLC癌组织及15例癌旁肺组织(距癌灶5 cm)中P-gp、MRP、LRP、P53及c-erbB-2的蛋白表达情况。结果:免疫组化显示P-gp、MRP、LRP、P53及c-erbB-2在肺癌组织中的阳性表达率分别是65.4%(51/78)、39.7%(31/78)、56.4%(44/78)、53.8%(42/78)及43.6%(34/78),均显著高于癌旁肺组织中的表达水平(P<0.05);MRP和LRP蛋白表达在不同病理类型(腺癌、鳞癌及大细胞癌)之间比较均具有显著性差异(P分别为0.008和<0.001),LRP及P53蛋白表达在不同病理分化程度之间具有显著性差异(P分别为0.025和0.026);c-erbB-2表达与P-gp、MRP、LRP、P53均有相关性(Spearman相关系数分别为0.317、0.401、0.519和0.341,P值分别为0.005、<0.001、<0.001和0.002),P53与MRP之间(Spearman相关系数为=0.260,P=0.022)以及LRP与MRP之间(Spearman相关系数为0.371,P=0.001)有相关性。结论:P-gp、MRP、LRP、P53及c-erbB-2这些蛋白的表达在NSCLC的多药耐药形成及肿瘤的发生发展中可能具有一定的协同作用。

葛根芩连汤有效成分对黄芩苷在Caco-2细胞模型中吸收转运的影响

目的采用LC-MS/MS法研究葛根芩连汤(葛根、黄芩、黄连、甘草)有效成分对黄芩苷在Caco-2细胞模型中吸收转运的影响。方法建立Caco-2细胞模型,采用细胞摄取实验和细胞转运实验评价多药耐药相关蛋白(MRP2)的功能。结果摄取实验中,黄芩苷的摄取量在60 min基本达到饱和[(0.68±0.07)ng/μg],加入MRP2抑制剂MK-571之后,黄芩苷的摄取量显著升高[(1.10±0.02)ng/μg,P<0.01],而P-gp转运蛋白抑制剂维拉帕米无此效果。配伍葛根素能提高黄芩苷的摄取量(P<0.05),而小檗碱、甘草苷的作用有统计学意义。细胞转运实验的结果表明,加入MRP2转运蛋白抑制剂后能增加黄芩苷从肠腔侧(AP)到基底侧(BL)侧的转运。配伍葛根素、甘草苷后能促进黄芩苷从AP到BL侧的转运,小檗碱无明显影响。结论 MRP2转运蛋白调控Caco-2细胞摄取吸收黄芩苷,推测其可能为MRP2转运蛋白的底物。葛根素可使在Caco-2细胞中黄芩苷被外排的量减少,从而增加黄芩苷的吸收量。

甘草提取物对小鼠肝脏核因子E2相关因子2及其下游基因表达的影响

目的考察甘草提取物对核因子E2相关因子2(Nrf2)信号通路及其下游基因尿苷二磷酸葡糖醛酸转移酶1A1(UGT1A1)、γ谷氨酰半胱胺酸合成酶(γGCS)、多药耐药相关蛋白1(MRP1)和多药耐药相关蛋白2(MRP2)的影响。方法 12只小鼠随机分为对照组和甘草提取物组(150 mg·kg-1)。给药后24 h处死取肝组织,采用qRT-PCR技术检测小鼠肝中Nrf2、UGT1A1、γGCS、MRP1和MRP2 mRNA的表达;Western blot技术测定Nrf2蛋白的表达。结果与对照组比较,甘草提取物显著诱导了小鼠肝脏中Nrf2 mRNA和蛋白的表达,同时Nrf2下游基因UGT1A1、γGCS、MRP1和MRP2 mRNA的表达也显著提高(均P<0.05)。结论甘草提取物诱导了小鼠肝脏中II相解毒酶UGT1A1、γGCS及转运体MRP1、MRP2,其机制可能与上调Nrf2转录因子的表达,激活Nrf2细胞信号转导通路有关。

茵栀黄颗粒对胆管结扎大鼠肝细胞膜转运体Mrp2、Ntcp及Bsep表达的影响

目的通过考察茵栀黄颗粒(茵陈、栀子、金银花和黄芩)对肝细胞膜转运体多药耐药相关蛋白2(Multidrugresistance-associated protein 2,Mrp2/ABCC2)、Na+-牛黄胆酸共转运多肽(Na+/taurocholate cotransporter,Ntcp/SLC10A1)及胆盐输出泵(Bile salt export pump,Bsep/ABCB11)表达的影响。方法胆管结扎术制备胆汁淤积大鼠模型;生化检测和HE染色,观察茵栀黄颗粒的干预效果;流式细胞仪测定肝脏转运体Ntcp、Bsep和Mrp2的表达。结果与模型组相比,茵栀黄组肝细胞的脂肪病变和水肿较模型组显著减轻(P<0.05),Mrp2的表达显著升高(P<0.01);但Ntcp、Bsep的表达无明显变化。结论肝细胞膜转运体Mrp2的表达升高可能是茵栀黄颗粒的退黄利胆分子机制之一。

HO-1与MRP2在原发性胆囊癌组织中的表达和意义

目的:检测血红素加氧酶-1(heme oxygenase,HO-1)与多药耐药相关蛋白2(multidrug resistance-associated protein2,MRP2)在原发性胆囊癌组织中的表达,探讨其与胆囊癌发生、发展的关系。方法:采用免疫组化SP法检测67例原发性胆囊癌患者中HO-1和MRP2的表达水平。结果:原发胆囊癌组织HO-1和MRP2表达的总阳性率分别为73.1%、77.6%。其中腺癌的阳性率为76.7%和80%。依据病理分级,HO-1和MRP2表达水平由高到低分别为III级>II级>I级,且具有统计学差异(P=0.028,P=0.023);HO-1、MRP2的阳性表达与年龄、性别等临床特征无相关性;HO-1和MRP2表达之间具有良好的相关性(r=0.324,P=0.005)。结论:HO-1和MRP2在原发性胆囊癌组织高表达,对胆囊癌的发生、发展提供有利条件,二者之间表达具有良好的相关性。

HAPLN1通过IKK/p65信号通路诱导大肠癌HT-29细胞产生MTX耐药

目的:研究甲氨蝶呤(methotrexate,MTX)耐药前后人大肠癌(结直肠癌)HT-29细胞中透明质酸蛋白聚糖连结蛋白1(hyaluronan and proteoglycan link protein 1,HAPLN1)表达的变化及其对MTX耐药性的影响,并探究可能的分子机制。方法:采用浓度梯度递增法构建耐药细胞株HT-29/MTX;RT-PCR检测HAPLN1和多药耐药相关蛋白2(multidrug resistance-associated protein 2,MRP2)的mRNA表达水平;采用脂质体介导法将人HAPLN1和MRP2基因的干扰质粒转染HT-29/MTX细胞并筛选出稳定表达的细胞系;采用CCK-8法检测细胞活力;流式细胞术检测细胞凋亡;采用Western blot检测HAPLN1、MRP2、IκB激酶(IκB kinase,IKK)α/β、p-IKKα/β(Ser176/Ser177)、p65和p-p65(Ser536)的蛋白水平。结果:HT-29/MTX细胞中HAPLN1和MRP2的mRNA和蛋白表达水平都显著高于其亲代HT-29细胞(P<0.05),耐药倍数高达463.756。抑制HAPLN1和MRP2基因表达使MTX对HT-29/MTX细胞的IC_(50)从15.304μmol/L分别降至6.119μmol/L和7.801μmol/L,逆转倍数分别为2.501和1.962,并增强MTX诱导的细胞凋亡(P<0.05)。敲减HAPLN1基因表达和使用IKK抑制剂IKK16均可下调IKKα/β和p65蛋白磷酸化水平以及MRP2蛋白表达水平(P<0.05),但IKK16未对HAPLN1蛋白表达产生影响(P>0.05)。结论:敲减HAPLN1基因表达可在体外增强人大肠癌耐药细胞株HT-29/MTX对MTX的敏感性,这可能与其抑制IKK/p65信号通路活化,继而下调MRP2基因表达有关。

Agkihpin对人肝癌SMMC-7721细胞COX-2、MRP1和E-CD表达的影响

目的探讨蛇毒精氨酸酯酶(Agkihpin)影响人肝癌SMMC-7721细胞活力、增殖和迁移的机制,为肝癌的治疗提供新的思路。方法取对数生长期SMMC-7721细胞随机分为8组,分别用质量浓度为0.207～4.130 g/mL的Agkihpin处理72 h,应用免疫细胞化学、Western blotting、RT-PCR法检测环氧合酶-2(COX-2)、表皮钙黏素(E-CD)和多药耐药相关蛋白1(MRP1)蛋白表达和基因转录水平,分析三指标之间的关系。结果与未行Agkihpin处理者比较,Agkihpin处理的SMMC-7721细胞COX-2基因转录、蛋白表达均降低(P<0.01),并呈一定的浓度依赖效应;COX-2与E-CD的表达和转录均呈负相关,MRP1与E-CD的表达和转录均呈负相关,COX-2与MRP1的表达和转录均呈正相关。结论 Agkihpin可通过下调MRP、COX-2表达及上调E-CD表达抑制人肝癌SMMC-7721细胞的活力、增殖和迁移,有望用于提高肝癌细胞对化疗药物的敏感性、逆转肝癌耐药细胞的多药耐药表型、提高肝癌患者术后生存率、抑制肝癌细胞的浸润和转移。

siRNA对K562和K562/ADM细胞耐药和凋亡的调节

目的研究联合转染以MRP和bcl-2基因为靶标的siRNA,对白血病细胞株K562和耐药的K562/ADM细胞药物敏感性和凋亡的影响。方法体外化学合成以多药耐药相关蛋白(MRP)和bcl-2为靶标的siRNA,分别或联合用脂质体转染入阿霉素处理的K562和K562/ADM以单纯化疗处理组和未处理组为对照。转染后24、48、72h,MTT法检测各组细胞生长抑制率,计算IC50值。转染24h后RT-PCR检测各组细胞相应靶基因mRNA表达水平,48h后流式细胞仪检测细胞MRP和bcl-2蛋白表达率和细胞凋亡率。结果K562/ADM细胞ADM的IC50为12.81μg/ml,ADM+MRP-siRNA组降为3.74μg/ml,ADM+bcl2-siRNA组降为6.82μg/mlADM+MRP-siRNA+bcl2-siRNA组降至2.51μg/ml;K562细胞ADM的IC50为6.75μg/ml,ADM+MRP-siRNA组降为3.22μg/ml,ADM+bcl2-siRNA组降为3.56μg/ml,ADM+MRP-siRNA+bcl2-siRNA降至1.84μg/ml,有统计学意义(P<0.01)。转染以MRP和bcl-2为靶标的siRNA后,细胞相应靶基因的mRNA及蛋白的表达明显减低,细胞凋亡率显著升高,联合转染两种siRNA,细胞的IC50进一步下降,细胞凋亡率进一步升高,与分别转染组相比有统计学差异(P<0.05);结论联合转染以MRP和bcl-2基因为靶标的siRNA,通过降低靶基因蛋白表达,产生协同作用,明显增加耐药和亲本肿瘤细胞药物敏感性和凋亡率。

外周血细胞P-gp、MRP2 mRNA检测在IgA肾病免疫抑制剂临床应用中的意义

目的:探讨糖皮质激素(glucocorticoid,GC)、免疫抑制剂在IgA肾病应用中的耐药机制,以提高临床诊治水平和判断预后的综合能力。方法:经肾活检诊断为IgA肾病(综合临床排除继发性IgA肾病)患者作为研究对象,按临床诊断和临床标准接受GC、免疫抑制剂治疗,观察疗效。治疗前留取外周血,提取细胞总RNA,通过实时荧光定量PCR(Real-Ti meRT-PCR)技术,测定IgA肾病患者外周血P-糖蛋白(P-glycoprotein,P-gp)、多药耐药相关蛋白2(multidrug resistance-associated protein 2,MRP2)mRNA表达,分析P-gp、MRP2 mRNA水平与GC、免疫抑制剂临床疗效和24 h蛋白尿(24 h UP)、肾小球滤过率(GFR)的相关性。结果:缓解组、显效组IgA肾病患者外周血P-gp mRNA平均显著低于有效组和无效组,有效组又显著低于无效组。患者外周血P-gp mRNA与治疗前24 h UP、GFR均无显著相关性,而与治疗后24 h UP呈显著正相关,与GFR呈显著负相关。缓解组患者MRP2 mRNA显著低于有效组和无效组,显效组显著低于无效组。MRP2 mRNA与治疗前24 h UP、GFR均无显著相关性,与治疗后24 h UP呈显著正相关,与GFR无显著相关。结论:IgA肾病患者外周血细胞P-gp、MRP2的高水平表达可能参与了GC、免疫抑制剂的耐药机制,影响了临床疗效。治疗前测定IgA肾病患者外周血P-gp、MRP2 mRNA表达对预测激素、免疫抑制剂的疗效有一定的参考价值。抑制IgA肾病患者外周血P-gp、MRP2的高表达则可能为提高临床疗效开辟另一途径。