Egr-1 Enhances Drug Resistance of Breast Cancer Cells by MDR1 Dependence

Abstract Paclitaxel (PTX) is one of the most effective drugs used in the treatment of breast cancer. Nonetheless, the appearance of MDR1 (multidrug resistance 1) in tumor cells has become a significant hindrance for efficacious chemotherapy. In this study, we show that the expression level of Egr-1 (early growth response gene-1) in cancer tissues (from paclitaxel chemotherapy failure patients) and MCF-7/PTX cells (the breast cancer cell line that was resistant to paclitaxel) was increased. Cell proliferation assay and apoptosis assay revealed that Egr-1 could promote cell growth and inhibit apoptosis in MCF-7/PTX. Mechanistic studies indicated that Egr-1 could bind to the proximal MDR1 promoter and enhance MDR1 transcription. These findings indicate that paclitaxel induced Egr-1 accumulation and upregulated the expression of MDR1, thereby inducing the drug resistance in MCF-7/PTX. Our results suggest a novel pathway by which paclitaxel induces MDR1 expression, possibly illuminating a potential target pathway for the prevention of MDR1-mediated drug resistance.

Effect of CYP3A5 and MDR1 gene polymorphism on blood concentration of tacrolimus and creatinine level in uremic patients during the early phase of kidney transplantation / 药学实践杂志

Objective To investigate the effect of CYP3A5 and MDR1 gene polymorphisms on blood concentration of tacrolimus and creatinine level in uremic patients during the early phase after kidney transplantation in real clinical practice. Methods 131 patients who underwent kidney transplantation for the first time with triple immunotherapy based on tacrolimus in single-center from 2013 to 2017 were enrolled for retrospective study. Tacrolimus daily dose, blood concentration, blood concentration-to-dose ratio, and serum level were compared according to the various genotypes of CYP3A5 and MDR1 polymorphisms in renal transplantation recipients, respectively. Results The dosage of tacrolimus in CYP3A5*3/*3 (GG) kidney transplantation recipients within 4 weeks after kidney transplantation was lower than those of CYP3A5*1/*1 (AA) and CYP3A5*1/*3 (AG). The serum creatinine levels of patients whose tacrolimus concentration in the range of 10-13 ng/ml were close to the normal value. Conclusion CYP3A5 gene polymorphism affects the blood concentrations of tacrolimus in renal transplant recipients. No association has been found between the blood concentrations of tacrolimus and MDR1 gene polymorphism. Tacrolimus concentration in the range of 10-13 ng/ml might contribute to restore the early kidney graft function.

Effect of Notoginseng Total Saponins on Changing Multidrug Resistance in HepG2/ Adriamycin Cells Through ERK/Akt Signaling / 中国实验方剂学杂志

Objective:To investigate the effect of notoginseng total saponins （TNS） on adriamycin （Adr） resistance in HepG2/Adr cells and the expression and activity of the mechanisms as the modulators of multi-drug resistance， so as to explore the possible mechanism of extracellular signal-regulated kinase （ERK） and protein kinase B （Akt） signaling pathways in reversing the resistance of HepG2/Adr cells mechanism. Method:Effect of TNS on HepG2/Adr cell proliferation was detected by thiazole blue （MTT） method. HepG2/Adr cells were treated with different concentrations （100， 50， 25， 0 mg·L^-1） of TNS and （20 μmol·L^-1） Adr respectively， and a blank group was set. The high-content screening platform was used to detect the accumulation of Adr in HepG2/Adr cells after 40 minutes， 3 hours and 6 hours. Western blot was used to detect the expression of P-glycoprotein /multidrug resistance/ATP binding cassette subfamily B member 1（P-gp/MDR1/ABCB1） and other drug resistance-related proteins and the main protein expression of ERK/Akt signaling pathway. The change of MDR1 on cell membranes was observed by laser confocal microscopy. Result:Compared with HepG2 cells， the expression of MDR1 in HepG2/Adr cells was significantly increased （<italic>P</italic><0.01）. Compared with the Adr group， the half-inhibitory concentration （IC₅₀） of TNS （25， 50， 100 mg·L^-1） and Adr （20 μmol·L^-1） co-administration group on HepG2/Adr cells <italic>in vitro</italic> significantly reduced （<italic>P</italic><0.01）， and the highest reversal multiple was 10 times. Compared with the Adr group， the co-administration group could significantly increase the accumulation of Adr in the cells （<italic>P</italic><0.05） in a dose-dependent manner. Compared with the blank group， the co-administration group could significantly reduce MDR1， ABC semitransporter （ABCG2）， multidrug resistance associated protein （MRP1）， ERK， phosphorylated extracellular regulatory protein kinase （p-ERK）， Akt， phosphorylated protein kinase B （p-Akt）， mammals， rapamycin target protein （mTOR） and phosphorylated mammalian rapamycin target protein （p-mTOR） （<italic>P</italic><0.05）， with the same results in the doxorubicin group. Compared with the blank group， there was no significant difference in the distribution and fluorescence intensity of MDR1 on the cell membrane between the Adr group and the notoginseng total saponins （25 mg·L^-1） group. Compared with the blank group and the doxorubicin group， TNS could significantly reduce the distribution of MDR1 on the cell membrane （<italic>P</italic><0.05）. Conclusion:TNS can inhibit the ERK/Akt pathway， reduce the expression of MDR1， and significantly increase the accumulation of doxorubicin in HepG2/Adr cells， which may be one of the mechanisms of notoginseng total saponins in reversing resistance.

Study on transport mechanism of brucine and strychnine in MDCK-MDR1 cell monolayer model / 中草药

Objective: To study the bi-direction transport behavior of brucine and strychnine in the MDCK-MDR1 cell monolayer model. Methods: MTT method was employed to confirm the safe concentration of brucine and strychnine towards MDCK-MDR1 cells. The effects of transport time, drug concentration, and P-glycoprotein inhibitor verapamil on cumulative absorption concentration (Ccum) and apparent permeability coefficient (Papp) of brucine and strychnine in MDCK-MDR1 monolayer cells were studied. Results: The Papp value of brucine and strychnine was larger than 1 × 10-5 cm/s and the ratio of Papp(BL→AP) vs Papp(AP→BL) was less than 2. Brucine/ strychnine combined with verapamil decreased the ratio of Papp(BL→AP) vs Papp(AP→BL). Conclusion: The absorption of brucine and strychnine in MDCK-MDR1 cell monolayer model was well and the passive transference was its main intestinal absorption mechanism. The P-gp inhibitor verapamil has a significant inhibitory effect on brucine and strychnine absorption. Brucine and strychnine may be a substrate of P-glycoprotein.

Association of MDR1 gene polymorphisms with refractory epilepsy in children / 中华医学遗传学杂志

Objective@#To assess the association of single nucleotide polymorphisms of multidrug resistance gene 1 (MDR1) with refractory epilepsy in children.@*Methods@#Peripheral blood samples were collected from 200 children with epilepsy and 100 healthy controls. Genomic DNA was extracted and subjected to PCR amplification, agarose gel electrophoresis and target site sequencing. Genotypes of rs1922242, rs2235048, rs10808072, rs868755 and rs1202184 loci of the MDR1 gene were analyzed.@*Results@#No significant difference was found in genotypic distribution and allelic frequencies of the rs1922242, rs2235048, rs10808072 and rs868755 loci between the drug-resistant and drug-sensitive groups. For the rs1202184 locus, a significant difference in genotypic distribution was found (P = 0.008). No significant difference was found in the frequencies of various haplotypes between the two groups.@*Conclusion@#Genotypes of the rs1202184 locus of the MDR1 gene are associated with refractory epilepsy in children, for which the AA genotype plays a dominant role.

Cis-2-dodecenoic Acid Mediates Its Synergistic Effect with Triazoles by Interfering with Efflux Pumps in Fluconazole-resistant Candida albicans / 生物医学与环境科学（英文）

OBJECTIVE@#To evaluate the synergy of the Burkholderia signaling molecule cis-2-dodecenoic acid (BDSF) and fluconazole (FLU) or itraconazole (ITRA) against two azole-resistant C. albicans clinical isolates in vitro and in vivo.@*METHODS@#Minimum inhibitory concentrations (MICs) of antibiotics against two azole-resistant C. albicans were measured by the checkerboard technique, E-test, and time-kill assay. In vivo antifungal synergy testing was performed on mice. Analysis of the relative gene expression levels of the strains was conducted by quantitative reverse-transcription polymerase chain reaction (qRT-PCR).@*RESULTS@#BDSF showed highly synergistic effects in combination with FLU or ITRA with a fractional inhibitory concentration index of ⪕ 0.08. BDSF was not cytotoxic to normal human foreskin fibroblast cells at concentrations of up to 300 μg/mL. The qRT-PCR results showed that the combination of BDSF and FLU/ITRA significantly inhibits the expression of the efflux pump genes CDR1 and MDR1 via suppression of the transcription factors TAC1 and MRR1, respectively, when compared with FLU or ITRA alone. No dramatic difference in the mRNA expression levels of ERG1, ERG11, and UPC2 was found, which indicates that the drug combinations do not significantly interfere with UPC2-mediated ergosterol levels. In vivo experiments revealed that combination therapy can be an effective therapeutic approach to treat candidiasis.@*CONCLUSION@#The synergistic effects of BDSF and azoles may be useful as an alternative approach to control azole-resistant Candida infections.

Two natural molecules preferentially inhibit azole-resistant Candida albicans with MDR1 hyperactivation / 中国天然药物

Antifungal drug resistance is a significant clinical problem, and antifungal agents that can evade resistance are urgently needed. In infective niches, resistant organisms often co-existed with sensitive ones, or a subpopulation of antibiotic-susceptible organisms may evolve into resistant ones during antibiotic treatment and eventually dominate the whole population. In this study, we established a co-culture assay in which an azole-resistant Candida albicans strain was mixed with a susceptible strain labeled with green fluorescent protein to mimic in vivo conditions and screen for antifungal drugs. Fluconazole was used as a positive control to verify the validity of this co-culture assay. Five natural molecules exhibited antifungal activity against both susceptible and resistant C. albicans. Two of these compounds, retigeric acid B (RAB) and riccardin D (RD), preferentially inhibited C. albicans strains in which the efflux pump MDR1 was activated. This selectivity was attributed to greater intracellular accumulation of the drugs in the resistant strains. Changes in sterol and lipid compositions were observed in the resistant strains compared to the susceptible strain, and might increase cell permeability to RAB and RD. In addition, RAB and RD interfered with the sterol pathway, further aggregating the decrease in ergosterol in the sterol synthesis pathway in the MDR1-activated strains. Our findings here provide an alternative for combating resistant pathogenic fungi.

Nkx-2.5 Regulates MDR1 Expression via Its Upstream Promoter in Breast Cancer Cells

BACKGROUND: Increased expression of MDR1 gene is one of the major mechanisms responsible for multidrug resistance in cancer cells. Two alternative promoters, upstream and downstream, are responsible for transcription of MDR1 gene in the human. However, the molecular mechanism regarding the transactivation of MDR1 upstream promoter (USP) has not been determined. METHODS: Dual-luciferase reporter gene assays were used to assess the effect of Nkx-2.5 on MDR1 USP activity using reporter plasmids for human MDR1 USP and its mutants. MDR1 mRNA level was examined by quantitative real-time PCR. The direct binding of Nkx-2.5 to the USP of MDR1 was evaluated by promoter enzyme immunoassays and chromatin immunoprecipitation assays.

Development of an oligonucleotide microarray for simultaneous detection of two canine MDR1 genotypes and association between genotypes and chemotherapy side effects

Canine MDR1 gene mutations produce translated P-glycoprotein, an active drug efflux transporter, resulting in dysfunction or over-expression. The 4-base deletion at exon 4 of MDR1 at nucleotide position 230 (nt230[del4]) in exon 4 makes P-glycoprotein lose function, leading to drug accumulation and toxicity. The G allele of the c.-6-180T>G variation in intron 1 of MDR1 (single nucleotide polymorphism [SNP] 180) causes P-glycoprotein over-expression, making epileptic dogs resistant to phenobarbital treatment. Both of these mutations are reported to be common in collies. This study develops a more efficient method to detect these two mutations simultaneously, and clarifies the genotype association with the side effects of chemotherapy. Genotype distribution in Taiwan was also investigated. An oligonucleotide microarray was successfully developed for the detection of both genotypes and was applied to clinical samples. No 4-base deletion mutant allele was detected in dogs in Taiwan. However, the G allele variation of SNP 180 was spread across all dog breeds, not only in collies. The chemotherapy adverse effect percentages of the SNP 180 T/T, T/G, and G/G genotypes were 16.7%, 6.3%, and 0%, respectively. This study describes an efficient way for MDR1 gene mutation detection, clarifying genotype distribution, and the association with chemotherapy.

Effects of Hydrophobic Structure of Amphiphilic Polymers on the Activity of P-glycoprotein in MDCK-MDR1 Cell / 中国药学杂志

OBJECTIVE: To determine the effects of the amphiphilic block polymers, which have the same hydrophilic block with the different hydrophobic block, on the function of P-glycoprotein(P-gp). METHODS: The three different micelles were prepared by film dispersion method. The particle sizes and distributions were measured by dynamic light scattering. Critical micelle concentrations(CMC) were detected by fluorescence probe technique with the pyrene. Rhodamine 123, a specific probe substrate of P-gp, was applied to determine the effects of polymers on the function of P-gp using uptake and efflux method. RESULTS: The particle sizes of mPEG-PCL, mPEG-PDLLA, mPEG-PLGA were (55.9±0.2), (53.7±1.1) and (61.6±0.6)nm. The CMC values were 2.08, 5.42 and 26.4 μg·mL-1. R123 accumulation in Madin-Darby canine kidney/multidrug resistance 1(MDCK-MDR1)cell detected by uptake assay increased to a maximum in the presence of polymers at concentrations of 250 μg·mL-1 for mPEG-PCL, 1~25 μg·mL-1 for mPEG-PDLLA and mPEG-PLGA. In efflux assay, mPEG-PCL, mPEG-PDLLA, mPEG-PLGA decreased the percentage of efflux of R123 at concentrations above the CMC, below/at the CMC or below the CMC respectively, showed the similar RESULTS with uptake assay. CONCLUSION: The mPEG-PCL, mPEG-PDLLA, mPEG-PLGA polymers might have a potential to inhibit the efflux activity of P-gp, which was likely related to the structures of hydrophobic segments, concentrations and existing states of the polymers.

Effects of microemulsion on transport and mechanism of puerarin in MDCK-MDR1 cells / 中草药

Objective To explore the effect of microemulsion on the transport and mechanism of puerarin in blood brain barrier (BBB) cell model MDCK-MDR1. Methods MTT assay was used to evaluate the cytotoxicity of puerarin microemulsion and solution, and determine the appropriate concentration of administration. The bilateral transport characteristics of puerarin solution-microemulsion was investigated in MDCK-MDR1 monolayer. Immunohistochemical staining was used to study the expression of tight junction proteins, and the changes in cell membrane fluidity was studied by fluorescence bleaching recovery, and the changes of membrane potential was measured by anion probe combined with flow cytometry. The mechanism of the effect of microemulsion on puerarin transport was clarified. Results The MDCK-MDR1 showed no significant toxicity when the mass concentration of puerarin solution ranged from 50 to 300 μg/mL and the microemulsion dilution was over 500 times. The Papp value in absorption direction of puerarin solution on MDCK-MDR1 monolayer was 1.04 × 10-6 cm/s, and the Papp value of excretion direction was 1.05 × 10-6 cm/s. The Papp value of puerarin in microemulsion was significantly increased compared with that in solution (P < 0.05). Microemulsification could reduce the expression of Claudin-1, Occludin, ZO-1, and F-actin in MDCK-MDR1, promote cell membrane flow, and decrease cell membrane potential. Conclusion Microemulsion can promote the bilateral transport of puerarin in the BBB cell model MDCK-MDR1. The mechanism is closely connected with the opening of tight junctions, increasing the cell membrane fluidity, making the cell depolarizing and reducing membrane potential, and increasing the permeation of paracellular.

Reversal of multidrug resistance by icaritin in doxorubicin-resistant human osteosarcoma cells / 中国天然药物

Multidrug resistance (MDR) is one of the major obstacles in cancer chemotherapy. Our previous study has shown that icariin could reverse MDR in MG-63 doxorubicin-resistant (MG-63/DOX) cells. It is reported that icariin is usually metabolized to icariside II and icaritin. Herein, we investigated the effects of icariin, icariside II, and icaritin (ICT) on reversing MDR in MG-63/DOX cells. Among these compounds, ICT exhibited strongest effect and showed no obvious cytotoxicity effect on both MG-63 and MG-63/DOX cells ranging from 1 to 10 μmol·L. Furthermore, ICT increased accumulation of rhodamine 123 and 6-carboxyfluorescein diacetate and enhanced DOX-induced apoptosis in MG-63/DOX cells in a dose-dependent manner. Further studies demonstrated that ICT decreased the mRNA and protein levels of multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1). We also verified that blockade of STAT3 phosphorylation was involved in the reversal effect of multidrug resistance in MG-63/DOX cells. Taken together, these results indicated that ICT may be a potential candidate in chemotherapy for osteosarcoma.

The individualized formular administration of tacrolimus after kidney transplantation based on the CYP3A5 and MDR1 gene polymorphism / 中华器官移植杂志

Objective To explore the feasibility and clinical significance of individualized formular administration of tacrolimus after renal transplantation based on the CYP3A5 and MDR1 gene polymorphism.Methods Total 129 renal transplantation recipients from Oct.1,2015 to July 30,2016 were included in this study and divided into 2 groups.In experimental group,tacrolimus was administrated by the individualized formula based on CYP3A5 and MDR1 gene polymorphism;in control group,tacrolimus was administrated by doctors' experience based on patient's body weight.The blood trough level of tacrolimus was determined 3 days after administration.The first blood trough level of tacrolimus,plasma creatinine level,acute rejection rate,and necessity for dialysis were compared between two groups.Results The first blood trough levels of tacrolimus in experimental and control groups were 9.24 ± 2.32 and 9.39 ± 3.47μg/L respectively (P＞0.05).The tacrolimus levels of 7 cases in experimental group and 18 cases in control group were not in normal range (P＜0.05).The plasma creatinine level at day 7 after surgery was 157.36 ± 110.55 μg/L in experimental group,and 174.01 ± 130.68μg/L in control group (P＞0.05).Acute rejection was found in both two groups:2 in experimental group and 5 in control group (P ＞ 0.05).There was significant difference in necessity for dialysis between two groups:4 in experimental group and 10 in control group (P＜0.05).Conclusion The individualized formular administration of tacrolimus based on the CYP3A5 and MDR1 gene polymorphism is more feasible and reasonable than experimental administration,which is more easier to come to an appropriate blood level and would benefit the early recovery of renal function.

Reversal of multidrug resistance by icaritin in doxorubicin-resistant human osteosarcoma cells / 中国天然药物

Multidrug resistance (MDR) is one of the major obstacles in cancer chemotherapy. Our previous study has shown that icariin could reverse MDR in MG-63 doxorubicin-resistant (MG-63/DOX) cells. It is reported that icariin is usually metabolized to icariside II and icaritin. Herein, we investigated the effects of icariin, icariside II, and icaritin (ICT) on reversing MDR in MG-63/DOX cells. Among these compounds, ICT exhibited strongest effect and showed no obvious cytotoxicity effect on both MG-63 and MG-63/DOX cells ranging from 1 to 10 μmol·L. Furthermore, ICT increased accumulation of rhodamine 123 and 6-carboxyfluorescein diacetate and enhanced DOX-induced apoptosis in MG-63/DOX cells in a dose-dependent manner. Further studies demonstrated that ICT decreased the mRNA and protein levels of multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1). We also verified that blockade of STAT3 phosphorylation was involved in the reversal effect of multidrug resistance in MG-63/DOX cells. Taken together, these results indicated that ICT may be a potential candidate in chemotherapy for osteosarcoma.

Mechanism underlying bergapten-mediated regulation of vincristine transport in MDCK-MDR1 cells / 中草药·英文版

Objectives: To investigate the effects of bergapten of Angelicae Dahuricae Radix on the transport of vincristine and its possible mechanism. Methods: The apparent permeability coefficient (Papp) for the transport of vincristine through the membrane of MDCK-MDR1 cells was used as an indicator of the effect of bergapten on vincristine transport. Molecular docking was employed to predict the binding force between bergapten and P-glycoprotein (P-gp). The effects of bergapten on P-gp function and P-gp ATPase activity were determined by rhodamine 123 (Rho123) accumulation and activity analysis, respectively. 1,6-Diphenyl-1,3,5-hexatriene (DPH) was used to study the effects of bergapten on membrane fluidity, and Western blotting and quantitative real-time PCR assays were performed to analyze the effect of bergapten on the protein and mRNA expression of P-gp, respectively. These experiments clarified the effects of bergapten on the transport of vincristine and allowed exploration of the possible mechanism underlying the effects of bergapten. Results: The results showed that bergapten could inhibit the transport of vincristine in MDCK-MDR1 cells, and the binding force between bergapten and P-gp was weaker. Bergapten could reduce the accumulation of Rh123 in MDCK-MDR1 cells, increase the membrane fluidity, and upregulate P-gp protein and mRNA expression but it had no effect on P-gp ATPase activity. Conclusions: Overall, we concluded that the possible mechanism through which bergapten inhibits vincristine transport was related to the bergapten-mediated upregulation of P-gp protein and mRNA expression, membrane fluidity or P-gp enzyme activity.

Meta-analysis of the Effects of Multi-drug Resistance Gene MDR1 C3435T Gene Polymorphism on Thera-peutic Efficacy of Proton Pump Inhibitors-based Triple Therapy for Helicobacter pylori Eradication / 中国药房

OBJECTIVE:To systematically evaluate the relationship of multi-drug resistance gene MDR1 C3435T gene polymor-phism with therapeutic efficacy of proton pump inhibitors (PPIs)-based triple therapy for Helicobacter pylori eradication. METH-ODS:Retrieved from PubMed,EMBbase,CBM,CJFD,Wanfang database and VIP,clinical studies about MDR1 C3435T gene polymorphism and PPIs-based triple therapy for the eradication of H. pylori infection were collected. Meta-analysis was performed by using Rev Man 5.3 statistical software after data extraction and quality evaluation by using STREGA statement. RESULTS:A to-tal of 7 studies were included,involving 1019 patients. The results of MDR1 C3435T genotyping in patients were classified as wild homozygote genotype(CC),mutant heterozygous genotype(CT)and mutant homozygote genotype(TT). The results of Me-ta-analysis showed that there was no statistical significance in the eradication rate of H. pylori among CC,CT and TT groups of MDR1 C3435T gene polymorphism [CC vs. CT:OR=0.99,95%CI(0.69,1.42) ,P=0.95;CC vs.TT:OR=1.44,95%CI(0.66, 3.15),P=0.36;CT vs.TT:OR=1.54,95%CI(0.86,2.73),P=0.14]. Subgroup analysis showed the eradication rate of H. pylori in CT genotype group was higher than that in TT genotype group among Asian population [OR=2.35,95%CI(1.53,3.62),P<0.001]. CONCLUSIONS:MDR1 C3435T gene polymorphism basically do not affect therapeutic efficacy of PPIs-based triple thera-py for H. pylori eradication. For Asian population,gene detection is useful for the treatment.

Effects of MDR1 C3435T Polymorphism on the Dose of Analgesia Agents after Joint Replacement / 中国药房

OBJECTIVE:To investigate the effects of multidrug resistance gene 1(MDR1)C3435T polymorphism on the dose of analgesia agents(dezocine combined with sufentanil)after joint replacement. METHODS:300 patients receiving joint replace-ment were selected from Tianjin People's Hospital and Tianjin Port Hospital during Jan. 2014-Feb. 2016. They were given dezocine and sufentanil for postoperative analgesia. PCR-RFLP was used to determine MDR1 C3435T polymorphism;VAS scores,Ramesy scores,the dose of dezocine+sufentanil and the occurrence of ADR were compared among different genotypes. RESULTS:Among 300 patients,there were 100(33.3%),102(34.0%)and 98(32.7%)cases of MDR1 C3435T CC,CT and TT genotype,respec-tively,the frequencies of which were all in line with Hardy-Weinberg balance (P>0.05). There was no statistical significance in VAS scores and Ramesy scores among different genotypes 0,24,48 h after surgery(P>0.05). No excessive sedation was found. The dose of dezocine+sufentanil in CT and TT genotype were all significantly lower than CC genotype 0-24 h,>24-48 h after sur-gery,with statistical significance(P0.05). The incidence of postoperative nausea and vomiting (PONV),ADR in TT genotype were significantly lower than CC and CT genotypes,with statistical significance (P0.05). CON-CLUSIONS:With similar sedation and analgesic effect,MDR1 mutant type have lower resistance to dezocine+sufentanil,and smaller drug dose is need,the incidence of ADR is lower. MDR1 genotype can be regarded as an important indicator of clinical in-dividualized treatment.

Effect of CDR1/CDR2 or MDR1 genes overexpression on oxidative stress in Candida albicans / 中国人兽共患病学报

To investigate the effect of CDR1/CDR2 or MDR1 genes overexpression on oxidative stress in Candida albicans,we evaluated the effect of H2O2 on cell viability in C.albicans overexpressing genes CDR1 /CDR2 or MDR1 and their parent strains.After establishing an oxidative stress model with H2O2,we detected reactive oxygen species (ROS),mitochondrial membrane potential (Δψm) and the expression of oxidative stress response-related genes (CAP1 and GRP2) and ROS clearance related-genes (SOD2 and SOD5).The results showed that C.albicans growth were inhibited by 100％ after the treatment of 5 mmol/L H2O2.HeO2 caused more ROS accumulation and Δψm reduction in parent strains than in CDR1/CDR2 or MDR1 genes overexpressed strains (P＜0.05).Compared to parent strains,the up-regulated expression of CAP1 and GRP2 were relatively less in CDR1/CDR2 or MDR1 genes overexpressed strains,moreover,the down-regulated expression of SOD2 and SOD5 were also relatively less in CDR1/CDR2 or MDR1 genes overexpressed strains (P＜0.05).In conclusion,the overexpression of CDR1/CDR2 and MDR1 genes could reduce the oxidative stress response and enhance the adaptability of C.albicans to oxidative stress.

Effect of arecoline hydrobromide on mRNA expression of hepatic and renal transporters in vivo / 中草药

Objective: To explore the effect of arecoline hydrobromide (AH) on the expression of rat hepatic and renal transporters. Methods: The effect of AH on the mRNA expression of 13 hepatic and renal transporters was studied after orally giver AH (0.8, 4, and 20 mg/kg/d) to rats for 21 d. Results: The results from the real-time PCR indicated that, AH treatment at low dose significantly decreased the mRNA levels of hepatic MRP2 and MDR1A, while significantly increased renal MRP5 mRNA level. On the other hand, AH treatment at high dose significantly inhibited the mRNA expression of hepatic OCT2, OAT2, OCTN2, OATP1A1, OATP1A4, OATP2B1, MRP2, and MDR1A, as well as renal MRP2, BCRP, and MDR1A. However, the mRNA expression of renal OCTN2, OATP1A1, OATP1A4, and MRP5 were significantly up-regulated following the treatment of high dose of AH. And the AH-induced effect on the above transporters was dose dependent in some extent. Conclusion: Due to the drug interaction caused by the alteration in expression and function of hepatic and renal transporters, it is suggested that the betel nut addicts should be paid more attention in case of adverse drug interactions.

GGI as a gene carrier delivering MDR1 siRNA to A549/DDP cells for reversal of multidrug resistance / 药学学报

This study was designed to reverse multidrug resistance of lung cancer cells by downregulating MDR1 genes through RNA interference (RNAi) technology. A novel biodegradable cationic polymer (PEG-bPLG-g-PEIs, GGI) was synthesized and characterized by 1H NMR. The particle size and zeta potential were measured by dynamic light scattering (DLS). The cell viability profile of GGI was tested by MTT method with both A549 and A549/DDP cell lines. Flow cytometry (FCM) technology was used to investigate the efficiency and intensity of delivering siRNA to cells by GGI polymer. RT-PCR and Western blot were used to detect the mRNA and P-gp expression after GGI/MDR1 siRNA transfection assay. The sensitivity of cisplatin administration after transfecting GGI/MDR1 siRNA polyplexs was performed with MTT and Annexin V-FITC/PI methods. The results suggest that the particle size and zeta potential of GGI/siRNA were 150-200 nm and 16-28 mV. GGI exhibited a lower cell cytotoxity than PEI 25K and higher efficiency of delivering siRNA, which dramatically decreased the expression of MDR1 mRNA and P-gp of A549/DDP cells and increased much sensitivity to cisplatin in A549/DDP cells. GGI holds a great potential in gene delivery as a novel cationic polymer for further investigation.