Levetiracetam plus Oxcarbazepine Combination Treatment Downregulates Serum Multidrug Resistance Protein 1 Levels and Upregulates Neuropeptide Y Levels in Children with Epilepsy

Abstract The aim of the present study was to investigate the usefulness of multidrug resistance protein 1 (MDR1) and neuropeptide Y (NPY) levels in predicting the efficacy of levetiracetam (LEV) plus oxcarbazepine (OXC) treatment administered to children with epilepsy and to determine their prognosis. Overall, 193 children with epilepsy admitted to the hospital were enrolled and randomly divided into two groups according to different treatment methods: group A (n = 106, treated with LEV plus OXC combination) and group B (n = 87, treated with OXC only). After treatment, compared with group B, group A exhibited a remarkably higher total effective rate and a significantly lower total adverse reaction rate. Areas under the curve for MDR1 and NPY for predicting ineffective treatment were 0.867 and 0.834, whereas those for predicting epilepsy recurrence were 0.916 and 0.829, respectively. Electroencephalography abnormalities, intracranial hemorrhage, neonatal convulsion, premature delivery, and MDR1 and NPY levels were independent risk factors for poor prognosis in children with epilepsy. Serum MDR1 and NPY levels exhibited a high predictive value for early epilepsy diagnosis, treatment efficacy assessment, and prognostication in children with epilepsy treated with LEV plus OXC combination.

Influence of 6-shogaol potentiated on 5-fluorouracil treatment of liver cancer by promoting apoptosis and cell cycle arrest by regulating AKT/mTOR/MRP1 signalling / 中国天然药物

Currently, chemoresistance seriously attenuates the curative outcome of liver cancer. The purpose of our work was to investigate the influence of 6-shogaol on the inhibition of 5-fluorouracil (5-FU) in liver cancer. The cell viability of cancer cells was determined by MTT assay. Liver cancer cell apoptosis and the cell cycle were examined utilizing flow cytometry. Moreover, qRT-PCR and western blotting was used to analyse the mRNA and protein expression levels, respectively. Immunohistochemistry assays were used to examine multidrug resistance protein 1 (MRP1) expression in tumour tissues. In liver cancer cells, we found that 6-shogaol-5-FU combination treatment inhibited cell viability, facilitated G0/G1 cell cycle arrest, and accelerated apoptosis compared with 6-shogaol or 5-FU treatment alone. In cancer cells cotreated with 6-shogaol and 5-FU, AKT/mTOR pathway- and cell cycle-related protein expression levels were inhibited, and MRP1 expression was downregulated. AKT activation or MRP1 increase reversed the influence of combination treatment on liver cancer cell viability, apoptosis and cell cycle arrest. The inhibition of AKT activation to the anticancer effect of 6-shogaol-5-FU could be reversed by MRP1 silencing. Moreover, our results showed that 6-shogaol-5-FU combination treatment notably inhibited tumour growth in vivo. In summary, our data demonstrated that 6-shogaol contributed to the curative outcome of 5-FU in liver cancer by inhibiting the AKT/mTOR/MRP1 signalling pathway.

Effects of Gelsemium elegans Combined with Mussaenda pubescens on Transporter BCRP and Drug-metabolizing Enzyme CYP3A11 / 中国实验方剂学杂志

ObjectiveTo explore the effect of Gelsemium elegans combined with Mussaenda pubescens on efflux transporter breast cancer resistance protein （BCRP） and cytochrome P450 3A11 （CYP3A11） and their attenuation mechanism， and to investigate whether the nuclear receptors were involved in such regulation by intervening it with nuclear receptor activators. MethodC57BL/6 mice were divided into the blank group， G. elegans （GE， 0.25 g·kg-1）group， GE + M. pubescens （MP） （0.25 g·kg-1+10 g·kg-1） group， GE + pregnane X receptor （PXR） activator （rifampicin）（GE + Rif，0.25 g·kg-1+50 mg·kg-1） group， GE + MP + Rif （0.25 g·kg-1+10 g·kg-1+50 mg·kg-1） group， GE + constitutive androstane receptor （CAR） activator （1，4-Bis ［2-（3，5-Dichloropyridyloxy）］ benzene， TCPOBOP）（GE + TCP， 0.25 g·kg-1+0.5 mg·kg-1） group， and GE + MP + TCP （0.25 g·kg-1+10 g·kg-1+0.5 mg·kg-1） group. The medication lasted for 14 successive days. One hour after the last administration， the mice were sacrificed by cervical dislocation and the liver tissue was harvested. The left liver tissue was stained with hematoxylin- eosin （HE） for observing the pathological changes. The right liver tissue was used for BCRP and CYP3A11 mRNA and protein expression detection by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. ResultThe survival rates of mice in the GE + Rif group， GE group， and GE + MP group were 25% （the lowest）， 40%， and 80%， respectively， and no death was observed in the other groups. Compared with the obvious lesions in the liver cells of the GE group， the pathological changes in liver cells of the GE + MP group were alleviated， while those in the GE + Rif group were worsened. Compared with the GE + Rif group， the GE + MP + Rif group exhibited relieved pathological changes in liver cells. Both the GE + TCP group and the GE + MP + TCP group showed mild liver lesions. The comparison with the GE + MP group revealed that the pathological changes in the GE + MP + TCP group were slightly relieved. Compared with the blank group， the expression of BCRP protein and mRNA in GE group were significantly decreased （P<0.05，P<0.01）.The expression of CYP3A11 protein in GE group were significantly decreased （P<0.01）. Compared with the GE group， the GE + MP group displayed remarkably up-regulated BCRP protein and mRNA expression （P<0.05，P<0.01） and CYP3A11 protein expression （P<0.05）， but slightly up-regulated CYP3A11 mRNA expression. Compared with the GE group， the GE + Rif group exhibited down-regulated BCRP protein expression （P < 0.05）. The protein and mRNA expression levels of BCRP were lower in the GE + MP + Rif group than in the GE + MP group （P<0.05，P<0.01）. The PXR activator rifampicin regulated BCRP before and after the combination of G. elegans with M. pubescens. The CYP3A11 protein and mRNA expression levels in the GE + TCP group were higher than those in the GE group （P<0.05，P<0.01）. Compared with the GE + MP group， the GE + MP + TCP group showed up-regulated CYP3A11 protein and mRNA expression （P<0.05，P<0.01）. CAR activator TCPOBOP also had a regulatory effect on CYP3A11 before and after the compatibility of G. elegans with M. pubescens. ConclusionThe attenuated toxin after the combination of G. elegans with M. pubescens is closely related to the efflux transporter BCRP and the drug-metabolizing enzyme CYP3A11.

Epithelial cell adhesion molecule promotes metastasis and multidrug resistance of breast cancer through induction of epithelial-mesenchymal transition / 中国药理学通报

Aim: To investigate the effect of epithelial cell adhesion molecule (EpCAM) on metastasis and multidrug resistance of breast cancer and its mechanism. Methods Immunohistochemical staining was employed to detect the expression of EpCAM in adjacent non-tumor tissues (ANTTs) and breast cancer tissues. siRNA was applied to knock down EpCAM expression in MDA-MB-231 cells. Transwell assay was used to detect the invasion and migration ability of breast cancer cells. Western blot analysis was performed to determine the protein expression of EpCAM, epithelial mesenchymal transition (EMT) markers E-cadherin, N-cadherin and vimentin, breast cancer resistance protein (BCRP), and β-catenin. Results EpCAM immunoreactivity was consistently stronger in primary breast cancer tissues and even higher in metastatic lesions than that in ANTTs. The expression of EpCAM was significantly upregulated in triple negative breast cancer MDA-MB-231 cells. EpCAM knockdown using siRNA decreased the invasion and migration ability and BCRP expression, and partially reversed the EMT phenotypes of MDA-MB-231 cells, β-catenin expression was upregulated in MDA-MB-231 cells. ICG-001, a specific Wnt/β-catenin pathway inhibitor, downregulated the expression levels of EpCAM, N-cadherin, and vimentin in MDA-MB-231 cells. Conclusions EpCAM could promote metastasis and drug resistance of breast cancer through the induction of EMT, which is related to the Wnt/β-catenin signaling pathway.

Discovery of novel diarylamides as orally active diuretics targeting urea transporters

Urea transporters (UT) play a vital role in the mechanism of urine concentration and are recognized as novel targets for the development of salt-sparing diuretics. Thus, UT inhibitors are promising for development as novel diuretics. In the present study, a novel UT inhibitor with a diarylamide scaffold was discovered by high-throughput screening. Optimization of the inhibitor led to the identification of a promising preclinical candidate,

The application of detecting BCAR1 (+)-circulating tumor cells in postoperative monitoring of early stage lung adenocarcinoma / 中华胸心血管外科杂志

Objective To explore the clinical significance regarding monitoring circulating tumor cells in early stage lung adenocarcinoma.Methods From November 2015 to January 2018,48 patients with stage Ⅰ lung adenocarcinoma were included in the study.BCAR1 expression in CTCs in peripheral blood were detected by using CanPatrolTM and RNA in situ hybridization detection.Results Among the 48 cases,CTCs and BCAR1 (+)-CTCs were detected in 41 cases(85.4％) and 30 cases(62.5％),respectively.Number of BCAR1 (+)-CTCs seemed to be significantly positively related to that of CTCs.BCAR1 (+)-CTCs were more likely to appear in the M-CTCS and E&M-CTCS.BCAR1 (+)-CTCs remarkably increased in three relapsed cases.Furthermore,there were 19 stable cases who had postoperative CTCs data:(1) in 12 patients,either CTCs or BCAR1 (+)-CTCs were significantly reduced or remained stable;(2) in 7 cases,CTCs increased,but BCAR1 (+)-CTCs remained stable in 2 cases,reduced in 1 case,and the other 4 cases underwent close follow-up.Conclusion Evaluation of BCAR1 (+)-CTCs possibly can be contributive to prediction of early lung adenocarcinoma recurrence or metastasis.

Comparison of Effect of Fine Powder and Ultrafine Powder of Dendrobium nobile Stem on Intestinal Transporters of Rats / 中国实验方剂学杂志

Objective:To compare the contents of alkaloids from fine and ultrafine powder of Dendrobium nobile stem in rat plasma,and investigate the effect of D. nobile stem with different particle sizes on gene expression of intestinal transporters. Method:Rats were randomly divided into the blank group,fine powder group of D. nobile stem(0.25 g·kg-1) and ultrafine powder group of D. nobile stem(0.25 g·kg-1).The rats were gavaged every 6 h for 5 days.The samples of rat plasma and small intestine were collected.The plasma samples were detected with UPLC-MS.The chromatography separation was performed on a Hypersil Gold C18 column(2.1 mm×150 mm,1.9 μm) with acetonitrile-0.1%formic acid solution as mobile phase for gradient elution.Electrospray ionization (ESI) was applied and operated in positive ion mode.The mRNA expression of multidrug resistance protein 1(MDR1),oligopeptide transporter protein 1(PEPT1),organic cation transporter protein 2(OCT2),breast cancer resistance protein 1(BCRP1),monocarboxylate transport protein 1(MCT1) and multidrug resistance related protein 2(MRP2) in small intestine were quantified by real time fluorescence quantitative polymerase chain reaction. Result:After intragastric administration of fine and ultrafine powder of D. nobile stem,dendrobine,mubironine B and dendramine could be detected in rat plasma.The contents of dendrobine and dendramine in the ultrafine powder group were significantly higher than that in the fine powder group(PD. nobile stem(PPD. nobile stem(PConclusion:Compared with the fine powder group of D. nobile stem,the plasma concentrations of dendrobine and dendramine in the ultrafine powder group are significantly increased,it may be related to the intestinal transporters of MDR1 and BCRP1.These results can provide experimental basis for selecting particle size of D. nobile stem.

Regulatory effects of Bmi-1 and MDR1 on the chemosensitivity of human non-small cell lung cancer cells to cisplatin / 医学研究生学报

Objective The purpose of this study was to investigate the mechanism of Bmi-1 regulating the sensitivity of non-small cell lung cancer (NSCLC) to chemotherapy by observing its effects on multidrug-resistance protein 1 (MDR1) and apoptosis-related proteins. Methods Small interfering RNAs (siRNA) targeting Bmi-1 were transfected into A549 and A549/DDP cells of NSCLC and the logarithmic-phase cells were randomly divided into a siRNA-Bmi-1, a siRNA-negative control and a blank control group. The A549 cells were treated with siRNA-Bmi-1, DDP or Bmi-1+DDP, or left untreated (the control). CCK8 assay was employed to measure the 50% inhibitory concentration (IC50) of cisplatin in the A549 and A549/DDP cells before and after treatment. The apoptosis of the cells was detected by flow cytometry, the mRNA expression of Bmi-1 determined by RT-PCR, and the relationship of Bmi-1 with MDR1 and cleaved caspase-3 proteins analyzed by Western blot. Results After transfection, the relative mRNA and protein expressions of Bmi-1 in the A549 and A549/DDP cells were significantly lower in the siRNA-Bmi-1 than in the blank control group (P < 0.05), but higher in the A549/DDP than in the A549 cells. The survival rates of the A549 and A549/DDP cells were decreased with the increased concentration of cisplatin (P < 0.05), even lower in the Bmi-1+DDP than in the DDP subgroup (P < 0.05). The apoptosis rate of the A549 cells was markedly higher in the Bmi-1+DDP than in the DDP, Bmi-1 and control groups ([39.65±3.41]% vs [23.11±1. 62] %, [2.05±1.56]% and [1.98±1.05]%, P < 0.05). After 24 hours of treatment with DDP, both the expressions of Bmi-1 and MDR1 were remarkably elevated, while the down-regulation of Bmi-1 significantly decreased the expression of MDR1 and increased that of cleaved caspase-3. Conclusion The expression of siRNA-Bmi-1 makes non-small lung cancer cells more sensitive to cisplatin, which might be associated with its inhibition of MDR1 expression and activation of apoptosis-related proteins.

Gadoxetic disodium-enhanced MRI to characterize T1 relaxation values and expression level of organic anion transporters and multidrug resistance protein on hepatocyte surface membrane of normal C57BL/6 mice / 中华肝脏病杂志

Objective@#The characteristics of T1 relaxation values and the expression levels of organic anion transport system (OATP) and multidrug resistance protein carrier (MRP) on hepatocyte surface membrane were quantitatively studied to evaluate liver function in normal C57BL/6 mice with gadoxetic disodium-enhanced MRI.@*Methods@#Ten 6-weeks-old, normal C57BL/6 mice were included in this study. Gadoxetic disodium- enhanced MRI examination was performed. Longitudinal relaxation time images before and 20 min after contrast injection (hepatobiliary-specific phase) were acquired. T1-relaxation time, T1 relaxation time decline rate (△T) and rapid initial enhancement slope percentage in the first-pass study of the liver parenchyma before and after administration of gadoxetate disodium were measured. Liver parenchyma specimens were detected by Western blotting and the values ​​of OATP1, MRP2, and MRP3 were recorded. Statistical results were expressed in mean.@*Results@#The mean T1 relaxation time of 10 normal C57BL/6 mice before and after enhancement was 659.13 ± 24.07, and 408.87 ± 27.21 ms. The mean T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study was 37.12% ± 4.95% and 4.14% ± 0.96% ms. Furthermore, the mean value of OATP1, MRP2 and MRP3 were 29 952.1 ± 11 475.2, 34 376.4 ± 33 228.4 and 357 308.9 ± 64 646.5.@*Conclusion@#T1-relaxation values, T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study before and after gadoxetic disodium-enhanced MRI were determined in normal C57BL/6 mice as well as quantitative values of OATP1, MRP2 and MRP3 at the molecular level on the hepatocyte surface membrane were helpful for liver injury model with control study.

Mechanisms of doxorubicin resistance of breast cancer MCF-7 cells mediated by exosomes / 药学学报

This study aimed to explore the roles of exosomes in doxorubicin-resistance in breast cancer cells. Using breast cancer parental cell line (MCF-7), doxorubicin-resistant cell line (MCF-7/ADR) and sensitive cell line co-cultured with doxorubicin-resistant supernatant (MCF-7/EXO) as models, the effects of doxorubicin on proliferation or apoptosis of MCF-7, MCF-7/EXO and MCF-7/ADR cells were detected by CCK8, and light or fluorescent microscopy. Exosomes in the supernatants of cell culture were extracted by ultracentrifugation, and the quantity of exosomes was determined by transmission electron microscopy, BCA and DiI labeling assay. Expression levels of exosome-specific biomarkers CD63 and Flotillin-1 were detected by Western blot. The uptake of MCF-7/ADR cell-derived exosomes by MCF-7 cells was observed by laser confocal microscopy. Western blot was used to detect the expression levels of multidrug resistance protein ATP-binding cassette subfamily B member 1 (ABCB1) in all three cell strains. Cell proliferation assays showed that IC50 of MCF-7/EXO cells to doxorubicin was 0.83 ± 0.09 μmol·L-1, which was significantly higher than 0.15 ± 0.05 μmol·L-1 (P<0.01) of MCF-7 cells, suggesting 5.5 times of increase in drug resistance. Apoptosis of MCF-7 cells was induced after doxorubicin treatment (P<0.001), but MCF-7/EXO cells were not significantly different (P>0.05). Exosome quantification and specific marker detection showed that MCF-7/EXO cells had significantly more exosomes than MCF-7 cells (P<0.05). PKH67 tracer markers indicated that MCF-7/ADR-derived exosomes could be taken up by MCF-7 cells. Western blot showed that the expression level of ABCB1 protein in MCF-7/EXO cells was significantly higher than that in MCF-7 cells. Taken together, these results indicate that exosomes of doxorubicin-resistant breast cancer cells can transmit drug resistance to sensitive cells, and the underlying mechanism may involve ABCB1 protein transport mediated by exosomes.

Effect of baicalein on reversal of multidrug resistance in MCF-7/MX cells in vitro and its mechanisms / 中国药理学通报

Aim To investigate the effect of baicalein on the reversal of multidrug resistance ( MDR) media-ted by breast cancer resistance protein ( BCRP) in hu-man breast cancer MCF-7/MX cells, and explore the possible mechanisms. Methods MTT assay was per-formed to determine the cytotoxicity of baicalein and susceptibility of chemotherapeutic drugs. The protein expression levels of BCRP, p-p38 MAPK and NF-κB p65 were determined by Western blot. Results MCF-7/MX cells were not only resistant to MX but cross-re-sistant to 5-FU and DDP, and the resistance index was 70. 45, 6. 68 and 21. 47, respectively. 2. 5, 5μmol· L-1 of baicalein could increase the sensitivity to above chemotherapeutic agents and decrease the expression levels of BCRP, p-p38 MAPK and NF-κB p65 in MCF-7/MX cells. Conclusion Baicalein can effec-tively reverse MDR of MCF-7/MX by down-regulating BCRP expression through p38/MAPK and NF-κB path-ways.

Effect of different concentrations of Gegen Qinlian decoction on expression of P-glycoprotein and multi-drug resistance protein transporter in Caco-2 cells / 中国中药杂志

To investigate the effects of Gegen Qinlian decoction on the expression of P-glycoprotein (P-gp) and multi-drug resistance protein (MRP) in epithelial cells of human colon adenocarcinoma Caco-2 cells．The effects of different concentrations of Gegen Qinlian decoction on the expression levels of p-gp and MRP1-6 mRNA in Caco-2 cells were detected by real time quantitative reverse transcriptase PCR (qRT-PCR).12 h after drug treatment (5.00 g·L⁻¹), the expression levels of MDR1 and MRP1-6 were significantly down-regulated at concentration of 5.00 g·L⁻¹; the mRNA expression levels of MDR1，MRP1，MRP2，MRP4，MRP5 and MRP6 were significantly down-regulated at concentration of 2.50 g·L⁻¹; only the expression levels of MRP2 and MRP5 were significantly affected at concentration of 1.00 g·L⁻¹. The results showed that the expression levels of MDR1 and MRP1-6 mRNA in Caco-2 cells could be down-regulated in a dose-dependent manner. Gegen Qinlian decoction may reduce drug efflux by down-regulating the mRNA expression of cell transporters in Caco-2 cell, and increase the time of drug action, thereby enhancing the bioavailability of chemotherapeutic drugs.

Chrysosplenetin, in the absence and presence of artemsininin, alters breast cancer resistance protein-mediated transport activity in Caco-2 cell monolayers using aristolochic acid I as a specific probe substrate

ABSTRACT The present study describes the impact of chrysosplenetin, in the absence and presence of artemisinin, on in vitro breast cancer resistance protein-mediated transport activity in Caco-2 cell monolayers using aristolochic acid I as a specific probe substrate. We observed that novobiocin, a known breast cancer resistance protein active inhibitor, increased Papp (AP-BL) of aristolochic acid I 3.13 fold (p < 0.05) but had no effect on Papp (BL-AP). Efflux ratio (PBA/PAB) declined 4.44 fold (p < 0.05). Novobiocin, consequently, showed a direct facilitation on the uptake of AAI instead of its excretion. Oppositely, both artemisinin and chrysosplenetin alone at dose of 10 µM significantly decreased Papp (BL-AP) instead of Papp (AP-BL). Chrysosplenetin alone attenuated the efflux ratio, which was suggestive of being as a potential breast cancer resistance protein suppressant. Oddly, Papp (BL-AP) as well as efflux ratio were respectively enhanced 2.52 and 2.58 fold (p < 0.05), when co-used with artemisinin and chrysosplenetin in ratio of 1:2. The potential reason remains unclear; it might be relative to binding sites competition between artemisinin and chrysosplenetin or the homodimer/oligomer formation of breast cancer resistance protein bridged by disulfide bonds, leading to an altered in vitro breast cancer resistance protein-mediated efflux transport function.

Metabolism and Transport of 7，4'-dihydroxyflavone in Caco-2 Cell Model / 医药导报

Objective To study the effects of different transport protein on the transport of 7,4'-dihydroxyflavone (7,4'-DHF) and its metabolite (7,4'-DHF-S) in Caco-2 cell model.Methods Ultra performance liquid chromatography was employed to determinethe content of 7,4'-DHF and 7,4'-DHF-S incubation buffer,their structures were identified by LC-MS/MS.Bidirectional transport of Caco-2 cells model was used to investigate the influence of ko143 (the inhibitor of BCRP) and MK571 (the inhibitor of MRP2) on the transport of 7,4'-DHF and 7,4'-DHF-S,respectively.Results Metabolic product of 7,4'-DHF in Caco-2 monolayer cell was identified as one monosulfate;PDR of 7,4'-DHF was (1.43 ± 0.11),PDR of ko143 and MK571 on the apparent permeability of 7,4'-DHF was (1.59 ± 0.04) and (1.48 ± 0.07) (P ＞ 0.05);PDR of 7,4'-DHF-S was (1.60 ± 0.06);ko143 could significantly reduce the apparent permeability of 7,4'-DHF-S,and the PDR was (0.23 ±0.03) (P ＜ 0.01);MK571 had no significant effect on the apparent permeability of the 7,4'-DHF-S,and the PDR was (1.51±0.04) (P ＞ 0.05).Conclusion Caco-2 cells can mediate the suffonated reaction of 7,4'-DHF;7,4'-dihydroxyflavone sulfonated combination product may be a substrate for BCRP.

Effect of multidrug resistant associated protein 4 overexpression on lipopolysaccharide-induced vascular endothelial hyperpermeability and its mechanism / 中华危重病急救医学

Objective To investigate the effect of multidrug resistance protein 4 (MRP4) overexpression on lipopolysaccharide (LPS)-induced vascular endothelial hyperpermeability of rat pulmonary micro-vascular endothelial cells (PMVECs) and its molecule mechanism. Methods Three to six passages of PMVECs were cultured in vitro, and they were divided into three groups: the cells in LPS group were only challenged by LPS 10 μg/mL after being cultured in serum-free medium for 24 hours; the cells in Ad-shRNA and Ad-MRP4 groups were infected with the empty virus control or recombinant adenovirus expressing MRP4 for 2 hours, and then were cultured in serum-free medium for 24 hours followed by stimulation of LPS 10 μg/mL. Endothelial permeability was assayed by the Transwell chamber models at 2, 6, 12, and 24 hours after LPS stimulation. Intracellular cyclic adenosine monophosphate (cAMP) levels were detected by enzyme-linked immunosorbent assay (ELISA). The morphological characteristics and distribution of F-actin was determined by laser confocal fluorescence microscope. The protein expressions of MRP4,β-catenin, vascular endothelium-cadherin (VE-cad) and ZO-1 were measured by Western Blot. Results ① After LPS stimulation, endothelium permeability and intracellular cAMP levels in PMVECs were significantly increased, peaked at 12 hours, and then decreased after 24 hours. Compared with LPS group and Ad-shRNA group, PMVECs of Ad-MRP4 group were exhibited a significant increase in endothelial permeability [12-hour permeability (A value):1.88±0.06 vs. 1.12±0.17, 1.10±0.18] and a significant decrease in intracellular cAMP level [12-hour cAMP (μg/L):2.39±0.02 vs. 2.97±0.01, 3.00±0.02, all P 0.05).② Under laser confocal fluorescence microscope, after LPS stimulation, the stress fiber formation was induced in three groups. But there were pronounced irregular aggregation of fiber in PMVECs of Ad-MRP4 group. ③ Furthermore, compared with LPS group and Ad-shRNA group, protein expression of MRP4 in Ad-MRP4 group was dramatically increased (gray value: 0.76±0.03 vs. 0.44±0.02, 0.43±0.02, both P 0.05). Conclusion MRP4 overexpression can decrease intracellular cAMP levels, reduce intercellular junction protein expression, and then exaggerate LPS-induced vascular endothelial hyperpermeability.

Chemoresistance of multi-drug resistance malignant glioma cells mediated by DNA-PKcs and its molecular mechanism / 吉林大学学报(医学版)

Objective:To obesrve the influence of DNA-PKcs in the chemoresistance of multi-drug resistance malignant glioma cells,and to explore its molecuIar mechanism in chemoresistance.Methods:siRNA was used to construct the DNA-PKcs knockdown human glioma U251 cell line;Western blotting method was used to detect the expressions of DNA-PKcs in U251 cells (U251 cells), doxorubicin (ADM)resistant U251 cells (U251/ADM cells),DNA-PKcs knockdown and ADM resistant U251 cells (U251/ADM/siDNA-PKcs cells).CCK8 method was used to detect the cell proliferation activity in three groups;Western blotting method was used to detect the expressions of MDR1, pNF-κB/p6, total Akt, pAkt/T308 and pAKT/S473 in the cells in three groups. Results:The expression level of DNA-PKcs in U251/ADM cells was significantly higher than those in U251 cells and U251/ADM/siDNA-PKcs cells (P 0.05).Conclusion:DNA-PKcs can significantly enhance the chemoresistance of multi-drug resistance malignant glioma cells,the underlying mechanism is related to up-regulation of pAKT/S473,pNF-κB/p65 and MDR1 expressions.

Role of breast cancer resistance protein in drug disposition / 药学学报

Human breast cancer resistance protein (BCRP), an ATP-binding cassette (ABC) efflux transporter, is mainly responsible for the transport of many endogenous and xenobiotics. BCRP is expressed in different tissues, such as placental, intestinal epithelium, endothelial cells of brain microvessels, and renal proximal tubular cells. BCRP is considered as one of the key factor for the drug-drug interaction and individual difference in drug therapy. The review will provide an overview of the current knowledge on the discovery of BCRP and its physical function, transport mechanism, substrate and inhibitors, as well as its effect on the drug pharmacokinetics.

Advances in the research of pharmacogenomics of tamoxifen / 药学学报

Tamoxifen (TAM) is the most common nonsteroidal antiestrogen agent, which has been widely used in the prevention of recurrence of estrogen or progesterone receptor-positive breast cancer in patients. It is metabolized by cytochrome P450 oxidases to its active metabolite (4-hydroxytamoxifen, 4-OH-TAM) and endoxifen (EDF), which played a critical role in the therapy. 4-OH-TAM and EDF have 30-to 100-fold more potency than TAM in the suppression of estrogen-dependent breast cancer cell proliferation. CYP3A4 and CYP2D6, as the key drug-metabolizing enzymes in those metabolic actions, are known to have several alleles. Genetic polymorphisms of CYP2D6 and CYP3A4 will influence the plasma concentrations of active TAM metabolites and clinical outcomes for breast cancer patients treated with TAM. The genetic polymorphisms of drug transporters, involved in the disposition of active TAM metabolites, also have the potential to influence the plasma concentrations of active TAM metabolites and clinical outcome for the treatment of breast cancer. In this review, we summarized the association of the genetic polymorphisms in the metabolic enzymes and transporters involved in the metabolism and disposition of TAM with the metabolite concentration, efficacy and adverse effects of TAM, which provides a fundamental reference for further pharmacogenomic study and clinical use of TAM.

Correlation Analysis of the expression of HIF-1α and MRP in hepatocellular carcinoma / 国际检验医学杂志

Objective To analyze the correlation between liver tissue hypoxia inducible factor‐1α(HIF‐1α) protein expression and multidrug resistance protein (MRP) expression between .Methods Our hospital from March 2012 to March 2013 the Depart‐ment of Pathology of the liver paraffin‐embedded specimens of a total of 83 cases of specimen processing ,production of tissue sec‐tions ,HIF‐1αexpression was observed ,the positive expression of MRP .Results 83 cases of specimens in HIF‐1α 50 cases were positive ,the positive rate was 60 .2% ;of which the well‐differentiated tumor samples of HIF‐1α positive rate was 74 .1% ,signifi‐cantly higher than the 28 .0% poorly differentiated (P0 .05) .In 83 cases of samples ,58 samples were MRP positive ,the positive rate was 70 .0% ;MRP positive rate among the high degree of 77 .6% ,significantly higher than the 52 .0% poorly differentiated (P0 .05) .MRP expression in the same samples were positive ,the HIF‐1α expression was also significantly increased .Conclusion HCC HIF‐1αprotein expression and MRP expression has some relevance .