Analysis of multidrug effects by parameter method

目的：建立一种新的分析多药物联用效果（协同，相加或拮抗）的方法．方法：根据靶体动力学原理，引入药物等效性检验法，建立新的数学模型：Ｑ＝（Ｅｏ－Ｅｅ）／｜Ｅｅ·Ｗ－ｓｘ·Ｔ｜（Ｑ≤－１拮抗，Ｑ≥１协同，１＞Ｑ＞－１相加）其中Ｅｏ为药物联用实测效应拟合值，Ｅｅ为联用药效期望值，Ｗ为专业等效标准，大小据专业而定，一般为１０％（Ｗ＝０１）．ｓｘ为Ｅｏ和Ｅｅ共同标准误，Ｔ是单侧ｔ检验ｔ０．０５值．并设计不同实验，取得不同类型具有多重属性的数据，用此模型对实验结果进行分析，并与其他方法比较．结果：本法适用于能用Ｈｉｌ方程进行拟合的数据，质反应数据Ｅｍａｘ固定为１（１００％），不局限于联用药物是否作用于受体，联用药物数目不受限制，可对数据进行系统分析．所得结论为专业结论和统计结论的综合．结论：参数法能有效地分析多种类型联用数据     

Modulation of multidrug resistance by three bisbenzyl-isoquinolines in comparison with verapamil

比较轮环藤碱（Ｃｙｃ）、海岛轮环藤碱（Ｉｎｓｒ）和海岛轮环藤酚碱（Ｉｎｓｎ）与维拉帕米（Ｖｅｒ）体外调节多药耐药性（ＭＤＲ）的作用．方法：细胞毒试验采用ＭＴＴ法，细胞内阿霉素（Ｄｏｘ）积累采用荧光分光光度法测定．结果：Ｃｙｃ，Ｉｎｓｒ，Ｉｎｓｎ和Ｖｅｒ在ＭＤＲ细胞系ＭＣＦ７／Ａｄｒ和ＫＢｖ２００能显著调节Ｄｏｘ和长春新碱的耐药性，且其作用呈剂量依赖性．Ｃｙｃ，Ｉｎｓｒ，Ｉｎｓｎ和Ｖｅｒ均能增加ＭＣＦ７／Ａｄｒ细胞内Ｄｏｘ的积累．Ｃｙｃ和Ｉｎｓｒ调节ＭＤＲ作用明显优于Ｖｅｒ，而Ｉｎｓｎ的作用类似于Ｖｅｒ．结论：Ｃｙｃ，Ｉｎｓｒ和Ｉｎｓｎ能通过增加ＭＤＲ细胞内Ｄｏｘ的积累而调节ＭＤＲ．     

Reversal of P-glycoprotein-mediated multidrug resistance by a synthetic α-aminoxy peptidomimetic

Long-acting insulin products are desired that provide sustained blood glucose lowering without blood glucose level peaks. In the present study, to obtain the more desirable blood glucose lowering effect of long-acting insulin products, we investigated the effect of maltosyl-β-cyclodextrin (G(2)-β-CyD) on physicochemical properties and pharmacokinetics/pharmacodynamics of insulin glargine, which is the one of the most widely used insulin analog. G(2)-β-CyD increased the solubility and suppressed the aggregation of insulin glargine in phosphate buffer at 9.5, probably due to the interaction of G(2)-β-CyD with aromatic residues of the insulin glargine such as tyrosine. In addition, the dissolution rates of insulin glargine from its precipitates were increased by a complexation with G(2)-β-CyD. Subcutaneous administration of an insulin glargine solution with G(2)-β-CyD to rats gradually decreased blood glucose levels and provided a sustained blood glucose lowering effect without showing the glucose level peaks. These results suggest that G(2)-β-CyD can be a useful excipient for sustained release and a truly peak-less formulation of insulin glargine.     

Reversal of P—glycoprotein—mediated multidrug resistance by pyronaridine

An association between P-glycoprotein(Pgp) level and poor clinical outcome has been found.Efforts have been made to search for the modulators of tumor multidrug resistance (MDR) from the components of Chinese herbs and the molecules developed in China.Pyronaridine (PND)was found to be able to reverse MDR to doxorubicine(DOX) in K562/A02 and MCF7/ADR,expressing Pgp with more efficacy than verapamil.PDN increased the accumulation of DOX and reduced efflux of Rh123 in the two cell lines.The reversibility prersisted for at least 24h after removel of the drug from the culture medium.When administered orally or parenterally,PND significantly enhanced the in vivo antitumor activity of DOX in K562/A02 xenografts,but did not significantly increase the toxicity or alter the plasma pharmacokinetics of DOX.In view of PND has been safely used in clinic for the treatment of malaria for more than 20 years at high dose,the modulator might be the promision in the reversal of MDR in the clinic.     

Synthesis of nanodiamond–daunorubicin conjugates to overcome multidrug chemoresistance in leukemia

Nanodiamonds (NDs) are promising candidates in nanomedicine, demonstrating significant potential as gene/drug delivery platforms for cancer therapy. We have synthesized ND vectors capable of chemotherapeutic loading and delivery with applications towards chemoresistant leukemia. The loading of Daunorubicin (DNR) onto NDs was optimized by adjusting reaction parameters such as acidity and concentration. The resulting conjugate, a novel therapeutic payload for NDs, was characterized extensively for size, surface charge, and loading efficiency. A K562 human myelogenous leukemia cell line, with multidrug resistance conferred by incremental DNR exposure, was used to demonstrate the efficacy enhancement resulting from ND-based delivery. While resistant K562 cells were able to overcome treatment from DNR alone, as compared with non-resistant K562 cells, NDs were able to improve DNR delivery into resistant K562 cells. By overcoming efflux mechanisms present in this resistant leukemia line, ND-enabled therapeutics have demonstrated the potential to improve cancer treatment efficacy, especially towards resistant strains.From the Clinical EditorThe authors of this study demonstrate superior treatment properties of resistant leukemia cell lines by utilizing nanodiamond vectors loaded with daunorubicin, paving the way to clinical studies in the hopefully not too distant future.     

Molecular-weight-dependent, anionic-substrate-preferential transport of β-lactam antibiotics via multidrug resistance-associated protein 4

β-Lactam antibiotics have cerebral and peripheral adverse effects. Multidrug resistance-associated protein 4 (MRP4) has been reported to transport several β-lactam antibiotics, and its expression at the blood-brain barrier also serves to limit their distribution to the brain. Therefore, the purpose of this study was to clarify the structure-activity relationship of MRP4-mediated transport of β-lactam antibiotics using MRP4-expressing Sf9 membrane vesicles. The transport activity was evaluated as MRP4-mediated transport per MRP4 protein [nL/(min·fmol MRP4 protein)] based on measurement of MRP4 protein expression by means of liquid chromatography-tandem mass spectrometry. Cefotiam showed the greatest MRP4-mediated transport activity [8.90 nL/(min·fmol MRP4 protein)] among the β-lactam antibiotics examined in this study. Measurements of differential transport activity of MRP4 for various β-lactam antibiotics indicated that (i) cephalosporins were transported via MRP4 at a greater rate than were penams, β-lactamase inhibitors, penems, or monobactams; (ii) MRP4-mediated transport activity of anionic cephalosporins was greater than that of zwitterionic cephalosporins; and (iii) higher-molecular-weight anionic β-lactam antibiotics showed greater MRP4-mediated transport activity than lower-molecular-weight ones, whereas zwitterionic β-lactam antibiotics did not show molecular weight dependency of MRP4-mediated transport. These quantitative data should prove useful for understanding MRP-related adverse effects of β-lactam antibiotics and their derivatives.     

Down-regulation of survivin expression reversed multidrug resistance in adriamycin-resistant HL-60/ADR cell line

AIM: To investigate the ability of an antisense RNA eukaryotic expression plasmid pcDNA3.1/survivin in downregulating the expression level of survivin mRNA and survivin protein and reversed multidrug resistance (MDR) in adriamycin-resistant HL-60/ADR cell line. METHODS: The expression of survivin mRNA was measured by RTPCR and the expression of survivin protein was measured by Western blot. Caspase-3 activity was determined by Phar Mingen colorimetric assay kit. Apoptosis was assessed by flow cytometry. The chemosensitivity of HL-60/ADR cells to adriamycin (ADR) was measured by MTT assay. RESULTS: pcDNA3.1/survivin down-regulated the expression level of survivin mRNA and survivin protein obviously, and induced apoptosis of HL-60/ADR cells in a time-dependent manner during 12-48 h. After transient transfection with pcDNA3.1/survivin for 48 h, survivin mRNA decreased by 67％, survivin protein decreased by 57％, caspase-3 activity increased 4.37 times, and the apoptosis rate increased by 4.41％ compared wi     

Involvement of α-methylene-γ- and δ-lactones in the suppression of multidrug resistance in MCF-7 cells

Background

The development of multidrug resistance to chemotherapy remains a challenge in the treatment of cancer and is a major factor causing failure of many forms of chemotherapy. The ATP binding cassette (ABC) family of proteins are efflux pumps that transport various potentially dangerous substances out of the cells. Several of the ABC transporters are related to chemoresistance, as the rapidly dividing malignant cells use them to protect themselves from medical interventions. Inhibitors of ABC transporters have the potential to enhance the efficacy of anticancer drugs. Two new synthetic compounds, AD-06 and AD-013, were tested as possible multidrug resistance inhibitors in MCF-7 cells.

Are all drug addicts impulsive? Effects of antisociality and extent of multidrug use on cognitive and motor impulsivity

The purpose of this investigation was to examine the influence of antisociality and extent of multidrug use on cognitive and motor impulsivity among substance-dependent individuals (SDIs) that used primarily cocaine and/or heroin. One hundred currently abstinent male SDIs participated in the study. Extent of multidrug use and degree of antisociality, assessed with the Socialization Scale of the California Psychological Inventory (So-CPI), were used to classify participants into one of four groups: high antisocial/low multidrug use, high antisocial/high multidrug use, low antisocial/low multidrug use, and low antisocial/high multidrug use. All subjects completed the Iowa Gambling Task to assess cognitive impulsivity and the Stroop Task to measure motor impulsivity. Contrary to expectations, antisociality was associated with more advantageous performance on the Iowa Gambling Task, independent of extent of multidrug use. In contrast, greater multidrug use was associated with general psychomotor slowing on the Stroop Task. Results suggest that a subclinical form of antisociality may have a paradoxically facilitating effect on decision-making and cognitive impulsivity among SDIs.     

Preparation of psoralen polymer–lipid hybrid nanoparticles and their reversal of multidrug resistance in MCF-7/ADR cells

Multidrug resistance (MDR) is the leading cause of failure for breast cancer in the clinic. Thus far, polymer–lipid hybrid nanoparticles (PLN) loaded chemotherapeutic agents has been used to overcome MDR in breast cancer. In this study, we prepared psoralen polymer–lipid hybrid nanoparticles (PSO-PLN) to reverse drug resistant MCF-7/ADR cells in vitro and in vivo. PSO-PLN was prepared by the emulsification evaporation-low temperature solidification method. The formulation, water solubility and bioavailability, particle size, zeta potential and entrapment efficiency, and in vitro release experiments were optimized in order to improve the activity of PSO to reverse MDR. Optimal formulation: soybean phospholipids 50?mg, poly(lactic-co-glycolic) acid (PLGA) 15?mg, PSO 3?mg, and Tween-80 1%. The PSO-PLN possessed a round appearance, uniform size, exhibited no adhesion. The average particle size was 93.59?±?2.87?nm, the dispersion co-efficient was 0.249?±?0.06, the zeta potential was 25.47?±?2.84?mV. In vitro analyses revealed that PSO resistance index was 3.2, and PSO-PLN resistance index was 5.6, indicating that PSO-PLN versus MCF-7/ADR reversal effect was significant. Moreover, PSO-PLN is somewhat targeted to the liver, and has an antitumor effect in the xenograft model of drug-resistant MCF-7/ADR cells. In conclusion, PSO-PLN not only reverses MDR but also improves therapeutic efficiency by enhancing sustained release of PSO.     

Metabolism and disposition of gemfibrozil in Wistar and multidrug resistance-associated protein 2-deficient TR− rats

1. The roles of multidrug resistance-associated protein (Mrp) 2 deficiency and Mrp3 up-regulation were evaluated on the metabolism and disposition of gemfibrozil.

2. Results from in vitro studies in microsomes showed that the hepatic intrinsic clearance (CL_int) for the oxidative metabolism of gemfibrozil was slightly higher (1.5-fold) in male TR^? rats, which are deficient in Mrp2, than in wild-type Wistar rats, whereas CL_int for glucuronidation was similar in both strains.

3. The biliary excretion of intravenously administered [¹⁴C]gemfibrozil was significantly impaired in TR^? rats compared with Wistar rats (22 versus 93% of the dose excreted as the acyl glucuronides over 72?h). Additionally, the extent of urinary excretion of radioactivity was much higher in TR^? than in Wistar rats (78 versus 2.6% of the dose).

4. There were complex time-dependent changes in the total radioactivity levels and metabolite profiles in plasma, liver and kidney, some of which appeared to be related to the up-regulation of Mrp3.

5. Overall, it was demonstrated that alterations in the expression of the transporters Mrp2 and Mrp3 significantly affected the excretion as well as the secondary metabolism and distribution of [¹⁴C]gemfibrozil.     

Horizontal gene transfer—emerging multidrug resistance in hospital bacteria

The frequency and spectrum of antibiotic resistant infections have increased worldwide during the past few decades. This increase has been attributed to a combination of microbial characteristics, the selective pressure of antimicrobial use, and social and technical changes that enhance the transmission of resistant organisms. The resistance is acquired by mutational change or by the acquisition of resistance-encoding genetic material which is transfered from another bacteria. The spread of antibiotic resistance genes may be causally related to the overuse of antibiotics in human health care and in animal feeds, increased use of invasive devices and procedures, a greater number of susceptible hosts, and lapses in infection control practices leading to increased transmission of resistant organisms. The resistance gene sequences are integrated by recombination into several classes of naturally occurring gene expression cassettes and disseminated within the microbial population by horizontal gene transfer     

Ligustrazine derivate DLJ14 reduces multidrug resistance of K562/A02 cells by modulating GSTπ activity

Multidrug resistance (MDR) of tumor cells is a major obstacle in chemotherapeutic cancer treatment. Over-expression of glutathione S-transferase π (GSTπ) is one of the mechanisms contributing to MDR. In this study, we investigated the reversal of MDR by DLJ14, a ligustrazine derivate, in adriamycin (Adr) resistant human myelogenous leukemia (K562/A02) cells by modulating the expression of GSTπ and the activity of GST-related enzymes. In the MTT test, DLJ14 showed a weak inhibition on proliferation of both K562/A02 and K562 cells, while verapamil at the same concentration showed a much stronger inhibition. The sensitivity of K562/A02 cells to cytotoxic killing by Adr was enhanced by incubation with DLJ14 as a result of the increased intracellular accumulation of Adr. The accumulation of Adr induced by DLJ14 may due to down regulation of GST-related enzyme activity. Western blot analysis and RT-PCR showed that DLJ14 was able to inhibit the protein expression and mRNA expression of GSTπ in K562/A02 cells. Moreover, DLJ14 increased the expression of cellular c-Jun NH₂-terminal kinase (JNK) in K562/A02 cells exposure to Adr. This is consistent with the inhibition of GSTπ. These results demonstrate that DLJ14 may be an attractive new agent for the chemosensitization of cancer cells.     

Reversal of multidrug resistance by 5,5’-dimethoxylariciresinol-4-O-β-D-glucoside in doxorubicin-resistant human leukemia K562/DOX

Objective:

The objective of this study was to investigate the reversal effects of 5,5’-dimethoxylariciresinol-4’-O-β-D-glucoside (DMAG) extracted from traditional Chinese medicines Mahonia on multidrug resistance (MDR) of human leukemia cells to chemotherapeutic agents.

Materials and Methods:

MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to determine the effect of DMAG on doxorubicin sensitivity to K562/DOX cells. Propidium iodide /Hoechst 33342 double staining assay was used to investigate the effect of DMAG on doxorubicin-induced cellular apoptosis. Intracellular accumulation of doxorubicin and rhodamine 123 assay were performed to evaluate the effect of DMAG on drugs efflux activity of P-glycoprotein.

Results:

DMAG significantly enhanced the doxorubicin cytotoxicity to K562/DOX cells. In the presence of 1.0 μM of DMAG, the IC₅₀ of doxorubicin decreased from 34.93 ± 1.37 μM to 12.51 ± 1.28 μM. DMAG of 1.0 μM significantly enhanced doxorubicin-induced cell apoptosis in K562/DOX cells and the enhancement was time-dependent. A significant increase in accumulation of doxorubicin in the presence of DMAG was observed. After treatment of the K562/DOX cells for 1 h with 15.0 μM doxorubicin alone, the fluorescence intensity was 33093.12. With the addition of 1.0 μM of DMAG, the fluorescence intensity of doxorubicin was 2.3-fold higher. A significant increase of accumulation of rhodamine 123 in the presence of DMAG was also observed. With the addition of 1.0 μM of DMAG, the fluorescence intensity was increased by 49.11% compared with rhodamine 123 alone.

Conclusion:

DMAG was shown to effectively enhance chemosensitivity of resistant cells, which makes it might be a suitable candidate for potential MDR-reversing agents.KEY WORDS: 5,5’-dimethoxylariciresinol-4’-O-β-D-glucoside, doxorubicin, leukemia, multidrug resistance     

(±)-3,4-methylenedioxymethamphetamine and metabolite disposition in plasma and striatum of wild-type and multidrug resistance protein 1a knock-out mice

Mice lacking multidrug resistance protein 1a (mdr1a) are protected from methylenedioxymethamphetamine (MDMA)-induced neurotoxicity, suggesting mdr1a might play an important role in this phenomenon. We characterized MDMA pharmacokinetics in murine plasma and brain to determine if mdr1a alters MDMA distribution. Wild-type (mdr1a?/?) and mdr1a knock-out (mdr1a?/?) mice received i.p. 10, 20 or 40 mg/kg MDMA. Plasma and brain specimens were collected 0.3-4 h after MDMA, and striatum were dissected. MDMA and metabolites were quantified in plasma and striatum by gas chromatography-mass spectrometry. MDMA maximum plasma concentrations (C(max)) for both strains were 916- 1363, 1833-3546, and 5979-7948 μg/L, whereas brain C(max) were 6673-14,869, 23,428-29,433, and 52,735-66,525 μg/kg after 10, 20, or 40 mg/kg MDMA, respectively. MDMA and metabolite striatum/plasma AUC ratios were similar in both strains, inconsistent with observed MDMA neuroprotective effects in mdr1a?/? mice. Ratios of methylenedioxyamphetamine (MDA) and 4-hydroxy-3-methoxymethamphetamine (HMMA) AUCs exceeded 18% of MDMA's in plasma, suggesting substantial MDMA hepatic metabolism in mice. MDMA, MDA, HMMA, and 4-hydroxy-3-methoxyamphetamine maximum concentrations and AUCs exhibited nonlinear relationships during dose-escalation studies, consistent with impaired enzymatic demethylenation. Nonlinear increases in MDMA plasma and brain concentrations with increased MDMA dose may potentiate MDMA effects and toxicity.     

Correction to “Folic acid-conjugated liposomal vincristine for multidrug resistant cancer therapy”

<正>In the original version of this article on p 122, two inappropriate images were placed in B and C of Fig. 1, which didn’t represent the group of FA-PEG-LS and PEG-LS/VCR. In the revised graphic provided below, the appropriate images are used.These corrections do not change the results and conclusions of this work.     

Is steroid resistance related to multidrug resistance-I (MDR-I) in rheumatoid arthritis?

Both healthy ageing and rheumatoid arthritis (RA) are frequently associated with acquired steroid resistance. Here, we investigated the potential involvement of steroid resistance with multidrug resistance (MDR) and explored the impact of pathological ageing on lymphocyte sensitivity to glucocorticoids. Seventy-four RA patients and 26 healthy controls took part in this study. Peripheral blood mononuclear cells were isolated and T-cell sensitivity to glucocorticoids was measured in vitro. The functional activity of P-glycoprotein was analyzed by flow cytometry and ABCB1/MDR-1 gene polymorphisms were assessed in peripheral lymphocytes. Patients and controls had similar sensitivities to glucocorticoids. Only controls presented age-related immunological changes, including reduced T-cell proliferation and relative resistance to corticosterone. Patients had a higher percentage (72%) of lymphocytes actively extruding rhodamine 123 (Rh123(dim)) than controls (60%) in spite of similar P-glycoprotein activity. A higher percentage of Rh123(dim)+ lymphocytes was observed in patients who were more resistant to dexamethasone in vitro. The distribution of ABCB1 genotypes in RA patients did not differ significantly from that in controls and were not associated to steroid sensitiveness or disease activity. These data suggest that peripheral lymphocytes of arthritic patients are fully responsive to GCs in vitro in spite of displaying higher MDR activity.     

Reversal of tumor multidrug resistance by 2-phenyl-3-(3',5'-dimorpholinomethyl-4'-hydroxy)-benzoyl-indole(HWL-12)

目的：探讨吲哚衍生物ＨＷＬ１２逆转ＭＤＲ的作用及其作用机制．方法：细胞毒的测定用ＭＴＴ法；Ｐ糖蛋白的测定用我们新近建立的Ｆｕｒａ２ＡＭ法．细胞内阿霉素（Ｄｏｘ）的积累测定用荧光分光光度计法．结果：ＨＷＬ１２能显著地增加ＭＤＲ细胞内Ｆｕｒａ２的积累和逆转ＭＤＲ１７２倍．在ＨＷＬ１２的作用下，ＭＤＲ细胞内阿霉素的积累亦明显增加，但在介质中高钙或低钙离子浓度对Ｄｏｘ积累均无影响．结论：ＨＷＬ１２具有较强的逆转作用，它的逆转机制可能与增加ＭＤＲ细胞内阿霉素的积累有关，而与钙离子浓度无关．     

Trabectedin (ET-743, Yondelis™) is a substrate for P-glycoprotein,but only high expression of P-glycoprotein confers the multidrug resistance phenotype

Summary Trabectedin (ET-743, Yondelis™) is a novel anticancer drug currently undergoing phase II and III investigations. There are various and conflicting reports whether trabectedin is a substrate for P-glycoprotein (P-gp), an important factor in drug disposition and multi-drug resistance (MDR). We have now unambiguously shown that trabectedin is a P-gp substrate by investigating vectorial transport over monolayers of LLC-PK1 pig kidney and Madine-Darby Canine kidney (MDCK) cells and the mdr1a and/or MDR1 transfected subclones. We further characterized the cytotoxic effects and cellular accumulation of trabectedin in these cell lines as well as in a panel of other cell lines with high or moderate expression levels of P-gp. Trabectedin displayed the typical MDR phenotype only in highly P-gp expressing cell lines, but not in cell lines with expression levels more closely conforming to clinical samples, suggesting that P-gp will not confer resistance to trabectedin in cancer patients.