Transmembrane Efflux Pump Research Articles

Overcoming Clear Cell Ovarian Cancer Resistance to Taxol by an Oligo Arginine Transporter Conjugate

Objectives: Taxol remains first line treatment for all epithelial ovarian cancer (EOC). However, it has been shown that ovarian clear cell carcinoma (CCC), a rare histological subtype of EOC, often becomes resistant to platinum based therapy when at advanced stage. This chemo-resistant phenotype has led to a poorer prognosis in patients with CCC than in patients with serous subtypes. While many factors contribute to resistance; a major contributor is the active export of drugs from cells mediated by transmembrane efflux pumps that prevent drugs from reaching their intracellular targets. Our lab has developed a Taxol-oligoarginine conjugate that prevents export of the drug from serous papillary EOC leading to increased cell death. In this study we aim to assess whether this Taxol conjugate is effective in improving Taxol mediated cell death in platinum resistant Clear cell ovarian cancer.

ABCB1 gene polymorphism associated with clinical factors can predict drug-resistant tuberculosis.

Polymorphism in the ABCB1 gene encoding P-glycoprotein, a transmembrane drug efflux pump, contributes to drug resistance and has been widely studied. However, their association with rifampicin and ethambutol resistance in tuberculosis (TB) patients is still unclear. Genotype/allele/haplotype frequencies in c.1236C > T (rs1128503), c.2677G > T/A (rs2032582), and c.3435C > T (rs1045642) were obtained from 218 patients. Of these, 80 patients with rifampicin and/or ethambutol resistance were selected as the case group and 138 patients were selected for the control group through the results of their culture and drug-sensitive tests. Patients aged <18 years and HIV-positive serologic tests were excluded. ABCB1 polymorphisms were determined using a PCR direct-sequencing approach, and restriction fragment length polymorphism (RFLP). A nomogram was constructed to simulate a combined prediction of the probability of anti-TB drug resistance, with factors including genotype c.1236C > T (rs1128503) (P=0.02), clinical form (P=0.03), previous treatment (P=0.01), and skin color (P=0.03), contributing up to 90% chance of developing anti-TB drug resistance. Considering genotype analyses, CT (rs1128503) demonstrated an increased chance of anti-TB drug resistance (odds ratio (OR): 2.34, P=0.02), while the analyses for ethambutol resistance revealed an association with a rare A allele (rs2032582) (OR: 12.91, P=0.01), the haplotype TTC (OR: 5.83, P=0.05), and any haplotype containing the rare A allele (OR: 7.17, P=0.04). ABCB1 gene polymorphisms in association with others risk factors contribute to anti-TB drug resistance, mainly ethambutol. The use of the nomogram described in the present study could contribute to clinical decision-making prior to starting TB treatment.

Abstract 2046: Investigation of MDR1 in ovarian cancer using biodynamic imaging

Abstract Multidrug resistance is one of the main causes of ineffective treatment of ovarian cancer. Almost 80% of advanced cases have recurring malignancies after treatment, even after initial responsiveness to the usual platinum-based chemotherapeutics. One of the many mechanisms for resistance is the transmembrane drug efflux pump p-glycoprotein, encoded by the gene MDR1. It has been shown that overexpression of this protein in ovarian cancer is associated with poor chemotherapeutic response and multidrug resistance due to low intracellular accumulation of the drug. Its wide substrate specificity allows it to pump out several common drugs such as vincristine, paclitaxel, doxorubicin, and etoposide. Biodynamic imaging (BDI) is a low-coherence form of digital holography that provides deep 3D functional information on intratumor subcellular motility and provides spectral signatures related to drug mode of action and for mitosis, apoptosis, and necrosis. BDI is currently being used in clinical trials to identify drug resistance in patient tumor biopsies. It was hypothesized that ovarian cancer spheroids with varying degrees of platinum resistance and p-glycoprotein would have identifiable p-glycoprotein signatures that could serve as a spectral biomarker for drug resistance. Ovarian cancer tumor spheroids from the A2780 and SKOV3 cell lines were cultured with varying degrees of cisplatin to select for increasing platinum resistance and p-glycoprotein as detected by immunofluorescence and western blot analysis. Cells were grown as 3D spheroids and treated with anticancer drugs that are known p-glycoprotein substrates such as doxorubicin and paclitaxel. Treatments were used in combination with and without p-glycoprotein inhibitors such as verapamil and zosuquidar. For BDI, background spectral data was collected for 3 hrs and then for 9 hrs after drug treatment. Parallel experiments were done in 2D cultured cells in 96-well plates and cell viability was assessed with the XTT assay. A suppression of average intracellular motion in the low-frequency range (0.01 Hz) was observed when 20 µM verapamil was used in combination with 10 µM paclitaxel in A2780 cells. This result may be due to the microtubule stabilizing effect of paclitaxel. SKOV3 spheroids were treated with verapamil plus 10 µM doxorubicin. Doxorubicin treated spheroids have increased high (10 Hz) and low (0.01 Hz) spectral signatures indicative of apoptosis. Addition of MDR1 modulators resulted in frequency changes associated with a greater apoptotic response in SKOV3 spheroids. Modulation of p-glycoprotein alters the spectral response to drugs in a manner associated with the drug mode of action. A specific MDR1 spectral signature was not observed in these experiments but experiments with MDR1 silenced spheroids are underway to identify a possible signature. Citation Format: Gayatri Narayanan, David D. Nolte, Daniela Matei, Ran An, John J. Turek. Investigation of MDR1 in ovarian cancer using biodynamic imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2046. doi:10.1158/1538-7445.AM2017-2046

ACINETOBACTER MAIN CAUSE OF HOSPITAL ACQUIRED INFECTIONS: A REVIEW

Hospital acquired infections (HAIs) are mostly caused by Gram-negative organisms and is one of the major issues in patient safety. These infectionsare often associated with the medical processes of hospitals such as invasive medical devices and various surgical procedures. Gram-negativeorganisms account for most infections in the hospital environment because of their ability to acquire resistant against multiple antibiotics. Throughdifferent mechanisms including the synthesis of β- lactamases, overexpression of transmembrane efflux pump, loss of porins, synthesis of antibiotic modifying enzymes, target mutations, ribosomal mutation or modifications, mutations in lipopolysaccharide structure etc. these organisms have developed drug-resistant property and the genes encoded in plasmids play a vital role in developing the resistant. Among all Gram-negative bacteria, Acinetobacter baumannii is an emerging pathogen that accounts for about 80% of all reported infections. Although other species of Acinetobacter are also often associated with HAIs. Acinetobacter is non-motile, obligate aerobic Gram-negative coccobacillus and are ubiquitous free-living saprophytes in soil and water. It is commonly transmitted through medical devices such as ventilators, urinary catheters and other invasive devices in hospitals but its ability to colonize on the skin of individuals often increases the rate of transmission through person to person contact. Patients admitted to Intensive Care Unit (ICU) are at the major risk of getting infected by A. baumannii and these includes pneumonia/ ventilator associated pneumonia(VAP), bloodstream infections, wound abscesses, urinary tract infections etc.Keywords: HAI, Acinetobacter baumannii, β- lactamases, VAP

Tetrahydroquinolinone derivatives as potent P-glycoprotein inhibitors: design, synthesis, biological evaluation and molecular docking analysis.

P-glycoprotein (P-gp) is a transmembrane efflux pump that has been associated with ineffective cancer chemotherapy and multidrug resistance (MDR). Chemical inhibitors of P-gp could have potential cancer therapeutic applications by preventing or reversing MDR. To exploit this, we designed twenty-five tetrahydroquinolinone analogs bearing pyridyl methyl carboxylate at C3 and different substituents at C4 as MDR reversal agents. The inhibitory effects of the synthesized compounds against P-gp were assessed by flow cytometric determination of rhodamine 123 accumulation in P-gp over-expressing MES-SA/DX5 cells. Fluorescence imaging of intracellular rhodamine 123 accumulation in MES-SA/DX5 cells was also performed. Furthermore, the effect of active derivatives on the reduction of doxorubicin's IC50 in MES-SA/DX5 cells was evaluated using MTT assay. Molecular docking was used to confirm the binding mode of some of the synthesized compounds. Five compounds in group A, bearing a 2-pyridyl methyl ester substituent at the C3 position, significantly increased rhodamine accumulation at 25 μM comparable to verapamil, a well-established P-gp inhibitor, while only 2 compounds in group B bearing 3-pyridyl methyl ester at the same position had this effect. This study shows that tetrahydroquinolinones containing methyl pyridine esters could represent an attractive scaffold for the discovery of P-gp inhibitors as MDR reversal agents in cancer cells.

Discovery of novel N-phenyl 1,4-dihydropyridines with a dual mode of antimycobacterial activity

There is an urgent need for novel drugs for the treatment of tuberculosis (TB) due to the increasing prevalence of antibiotic resistance among Mycobacterium tuberculosis (Mtb) strains against first-line and second-line therapeutics. We developed novel N-phenyl 1,4-dihydropyridines as potential antituberculotic agents. The observed activity depends on the substitution patterns of the aromatic residues. N-unsubstituted 1,4-dihydropyridines are known inhibitors of the cancer-relevant transmembrane efflux pump ABCB1. Based on the similarity of ABCB1 amino acids sequences relevant to 1,4-dihydropyridine binding and the MTb efflux pump Rv0194, we determined ABCB1-inhibitory properties of our compounds in a cell line model. We identified one compound, which substantially increased the activity of two antituberculotic drugs which are substrates of ABCB1. The data indicate that our N-phenyl 1,4-dihydropyridines represent a novel compound class which improves the efficacy of anti-TB drugs by interfering with transmembrane efflux pumps in Mtb.

Intact soluble P-glycoprotein is secreted by sinonasal epithelial cells.

P-glycoprotein (P-gp) is a 170 kDa transmembrane efflux pump, which is upregulated in chronic rhinosinusitis. Studies of leukemia demonstrated that P-gp may also be secreted in an intact soluble form. The purpose of this study was to explore whether sinonasal epithelial cells were capable of secreting soluble P-gp and whether P-gp has any functional role. Soluble and cytoplasmic P-gp were quantified in vehicle and lipopolysaccharide exposed cultures by enzyme-linked immunosorbent assay. The molecular weight of the soluble P-gp was determined by Western blot. Naive cultures were exposed to recombinant human P-gp at 0-2000 ng/mL. The degree of membranous interpolation was determined by quantitative fluorescent immunocytochemistry and function was determined by a calcein acetoxymethyl ester assay. Soluble P-gp was secreted intact at 170 kDa. Mean (standard deviation) secretion was detected within vehicle wells at 55.43 ± 26.26 ng/mL, which significantly increased to 333.27 ± 305.98 ng/mL (p < 0.001) after lipopolysaccharide stimulation. Soluble P-gp strongly and significantly correlated with cytoplasmic P-gp (r = 0.57, p = 0.000001). Exposure to 2000 ng/mL of recombinant P-gp significantly increased corrected total cell fluorescence (1.34 ± 1.85) relative to vehicle control 0.29 ± 0.26 (p = 0.01) and significantly reduced calcein acetoxymethyl ester fluorescence (82.03 ± 43.69) relative to 100 ng/mL recombinant P-gp exposed cells (123.11 ± 42.16, p = 0.001). Cultured sinonasal epithelial cells were able to both secrete intact P-gp and could functionally interpolate soluble P-gp into their cell membrane. These in vitro findings indicated that soluble P-gp may be present in nasal mucus as a biomarker and could participate in the maintenance of P-gp overexpression in chronic rhinosinusitis and associated inflammation.

Niemann-Pick disease type C1(NPC1) is involved in resistance against imatinib in the imatinib-resistant Ph+ acute lymphoblastic leukemia cell line SUP-B15/RI

Niemann-Pick disease type C1 (NPC1) is involved in cholesterol trafficking and may normally function as a transmembrane efflux pump. Previous studies showed that its dysfunction can lead to cholesterol and daunorubicin accumulation in the cytoplasmic endosomal/lysosomal system, lead to Niemann-Pick disease and resistance to anticancer drugs. In the present study, NPC1 was shown by microarray analysis to be more highly expressed in the Ph+ acute lymphoblastic leukemia cell line SUP-B15/RI, an imatinib-resistant variant of SUP-B15/S cells without bcr-abl gene mutation established in our lab. Further investigation revealed a defect in the functional capacity of the NPC1 protein demonstrated by filipin staining accompanied by a lower intracellular imatinib mesylate(IM) concentration by high-performance liquid chromatography in SUP-B15/RI compared with SUP-B15/S cells. Furthermore, U18666A, an inhibitor of NPC1 function, was used to block cholesterol trafficking to imitate the NPC1 defect in SUP-B15/S cells, leading to higher NPC1 expression, stronger filipin fluorescence, lower intracellular IM concentrations and greater resistance against IM. Samples from non-mutated relapsed Ph+ ALL patients also showed higher NPC1 expression compared with IM-sensitive patients. Our experiment may reveal a new mechanism of IM resistance in Ph+ ALL.

Discovery of substituted 1,4-dihydroquinolines as novel promising class of P-glycoprotein inhibitors: First structure-activity relationships and bioanalytical studies.

Multidrug resistance (mdr) is the most important problem in the therapeutical treatment of cancer. One central problem in the resistance proceeding is the expression of transmembrane efflux pumps which transport drugs out of the cells. We developed novel substituted 1,4-dihydroquinolines as inhibitors of the transmembrane efflux pump P-glycoprotein. Structure-activity relationships are discussed for this first series. Promising active inhibitors have been identified and first bioanalytical studies have been carried out to address questions of cellular toxicity, P-gp substrate as well as mdr reversal properties.

Discovery of substituted 1,4-dihydroquinolines as novel class of ABCB1 modulators

Transmembrane efflux pumps are one main cause for multidrug resistance (mdr) of cancer. One hopeful approach to combate the mdr has been the development of inhibitors of the efflux pump activity. A novel class of small-molecule inhibitors of the most important efflux pump ABCB1 (P-glycoprotein) has been discovered. Inhibitory activities are discussed in relation to substituent effects. Most active compounds have been evaluated in first bioanalytical studies to reverse the mdr of an anticancer drug. Cellular toxicity and ABCB1 substrate properties of the compounds were investigated. A cellular induction of relevant efflux pump protein expressions was not observed under inhibitor application, so that our compounds are perspective candidates for further preclinical studies.

Discovery of 9,10-Dihydroacridines as Novel Class of ABCB1 Inhibitors.

Nonplanar 9,10-dihydroacridines were synthesized as promising C2 symmetric molecular scaffolds as inhibitors of the transmembrane efflux pump ABCB1. Within the series structure-activity relationships are discussed revealing the importance of hydrogen bond acceptor functions. A selectivity of ABCB1 inhibition is demonstrated for selected candidates and a bioanalytical study proved nontoxicity as well as missing ABCB1 substrate properties. The results encourage to further develop the promising class of ABCB1 inhibitors.

Novel non-substrate modulators of the transmembrane efflux pump P-glycoprotein (ABCB1)

Novel non-substrate modulators of the transmembrane efflux pump P-gp have been profiled as nontoxic and mdr reversing agents.

The inhibition of constitutive androstane receptor-mediated pathway enhances the effects of anticancer agents in ovarian cancer cells

BackgroundOvarian cancer is commonly treated with anticancer agents; however, many tumors become resistant. Resistance is regulated, in part, by P-glycoprotein, which is encoded by the gene multiple drug resistance 1 (MDR1) and functions as a transmembrane efflux pump for the elimination of anticancer agents. Constitutive androstane receptor (CAR) is a nuclear receptor that regulates drug metabolism through control of MDR1 and other genes. PurposeWe examined whether the inhibition of CAR-mediated pathway could influence the cytotoxicity of three anticancer drugs, cisplatin, paclitaxel, and arsenic trioxide, in ovarian cancer cells. ResultsWe observed that the cell proliferation of several ovarian cell lines expressing CAR significantly increased when CITCO was combined with anticancer agents compared with any anticancer agent alone. The up-regulation of MDR1 and UGT1A1 by anticancer agents was further enhanced in the presence of CITCO. We confirmed that combining CITCO with anticancer agents induced significantly lower levels of apoptosis than those achieved with any single anticancer drug. CAR down-regulation by RNA interference caused a significant increase in cell growth inhibition and enhancement of apoptosis in the presence of anticancer agents. Combination of CITCO with any anticancer agents significantly enhanced CAR-mediated transcription compared with any anticancer agents alone and CAR down-regulation completely inhibited the transcription in the presence of CITCO and/or anticancer agents. ConclusionInhibition of CAR pathway could be a novel therapeutic approach for the augmentation of sensitivity to anticancer agents, or to overcome resistance, in the treatment of ovarian cancer.

Crystal structure of the open state of the Neisseria gonorrhoeae MtrE outer membrane channel.

Active efflux of antimicrobial agents is one of the most important strategies used by bacteria to defend against antimicrobial factors present in their environment. Mediating many cases of antibiotic resistance are transmembrane efflux pumps, composed of one or more proteins. The Neisseria gonorrhoeae MtrCDE tripartite multidrug efflux pump, belonging to the hydrophobic and amphiphilic efflux resistance-nodulation-cell division (HAE-RND) family, spans both the inner and outer membranes of N. gonorrhoeae and confers resistance to a variety of antibiotics and toxic compounds. We here describe the crystal structure of N. gonorrhoeae MtrE, the outer membrane component of the MtrCDE tripartite multidrug efflux system. This trimeric MtrE channel forms a vertical tunnel extending down contiguously from the outer membrane surface to the periplasmic end, indicating that our structure of MtrE depicts an open conformational state of this channel.

Novel MDR-reversing inhibitors of MRP subtypes related to antiretroviral drug resistance and CD4 cell counts

Transmembrane efflux pumps play an increasing role in the success of ART. The occurrence of increasing mRNA levels of the efflux pump proteins P-gp and MRP subtypes has been associated with ART therapeutics like PIs and NNRTIs. Moreover, a relation has been suggested of MRP subtypes and CD4 cell counts. So there is a challenge to find selective MRP inhibitors which may reduce MRP-induced drug resistances as well as discussed effects on CD4 cells. We developed novel nonpeptidic inhibitors of important MRP subtypes related to both MRP-mediated resistances as well as reduced cell counts.

Influence of cytochrome P450 and ABCB1 genetic polymorphisms on drug efficacy in narcolepsy with cataplexy

Treatments for narcolepsy-cataplexy (NC) are so far only symptomatic and aim to reconsolidate sleep and waking states as well as cataplexy attacks. The patients’ clinical response is influenced by a high interindividual variability. This leads, in clinical practice, to an empirical case-by- case management, mainly based on increasing drug dosages, but without a precise clue of the mechanisms of such variability. Genetic polymorphisms of cytochrome P450 (CYP450) are involved in drug metabolism and known to be responsible for the interindividual variability of drug response in different population groups. We genotyped CYP450 genes, CYP3A4 and CYP3A5, involved in the metabolism of two common NC drugs (i.e. modafinil (Mod), a wake promoting agent, and venlafaxine (Ven), a noradrenaline- serotonine reuptake inhibitor). Moreover, we genotyped the glycoprotein-P ABCB1(P-gp), also called multidrug resistance protein 1, a transmembrane efflux pump. Finally, genotypes were correlated with Mod and Ven efficacy and dosage, to provide a clue for the interindividual variability in clinical response of NC patients. 45 Caucasian NC patients (28 males, mean age 42 ± 20 y.o.), on chronic therapy with Mod alone or Mod plus Ven underwent blood withdrawal for genetic analysis. Mod and Ven efficacy was empirically scored by a sleep expert (1 = full, 2 = mild, 3 = low efficacy). Multiplex PCR was used for CYP3A4, CYP3A5 and P-gp loci amplification, followed by enzymatic purification, minisequencing reaction, and capillary electrophoresis typing. Out of 45 patients 17 were on Mod alone (38%), 28 on Mod plus Ven (62%). No significant correlation was found between CYP3A4/CYP3A5 genotypes and Mod or Ven efficacy or dosage. The CGC/TTT P- gp-haplotype (wild type/mutated allele), corresponding to a decreased activity, showed a significant correlation with an increased Mod efficacy ( p = 0.017). CGC/TTT haplotype was also the most represented in NC, according to general Caucasian population frequency distribution. This is the first attempt to correlate the interindividual variability of drug response to Mod and Ven in NC patients with the genotypes of proteins involved in their metabolism and transport. An increased Mod efficacy resulted to be related to a partially decreased activity of P-gp (partially mutated haplotype), suggesting that the Mod efficacy may be related to the intracellular permanence of Mod, consequent to damaged cell efflux. We thank the patients of the Italian Narcolepsy Association (AIN) for the precious collaboration.

Drug Resistance in Natural Isolates of Leishmania donovani s.l. Promastigotes Is Dependent of Pgp170 Expression

Resistance of pathogens to drugs is a growing concern regarding many diseases. Parasites like Leishmania, Plasmodium and Entamoeba histolytica; and neoplastic cells, present the multidrug-resistant phenotype rendering chemotherapy ineffective. The acquired resistance of Leishmania to antimony has generated intense research on the mechanisms involved but the question has not yet been resolved. To test the hypothesis that drug efflux in Leishmania, as measured by flow cytometry using the fluorescent dye Rhodamine-123, is largely dependent on the number of efflux pumps an isolate can express, the amount of Pgp 170 molecules was assessed in ten field isolates (5 “resistant” and 5 “susceptible”) using: Western Blotting, Confocal and Transmission Electron Microscopy, and proteomics. Their survival after exposure to three antileishmanial drugs, in vitro, was evaluated and clinical data were compared to the in vitro results. All isolates were resistant to Glucantime but susceptible to Miltefosine, whilst Amphotericin B was more effective on the “susceptible” isolates. The MDR gene, expressing the transmembrane efflux pump Pgp 170, appears to play a key role in the phenomenon of drug resistance. When “susceptible” versus “resistant” parasites were compared, it was shown that the higher the number of Pgp 170 molecules the higher the Rhodamine-123 efflux from the parasite body and, when exposed to the drug, the number of efflux pumps increased. However, the rate of this increase was not linear and it is possible that there is a maximum number of Pgp 170 molecules an isolate can express. Nevertheless, the phenomenon is a complex one and other factors and proteins are involved in which the HSP-70 group proteins, detected in the “resistant” isolates, may play a significant role.

Fluorescent substrates for flow cytometric evaluation of efflux inhibition in ABCB1, ABCC1, and ABCG2 transporters

ATP binding cassette (ABC) transmembrane efflux pumps such as P-glycoprotein (ABCB1), multidrug resistance protein 1 (ABCC1), and breast cancer resistance protein (ABCG2) play an important role in anticancer drug resistance. A large number of structurally and functionally diverse compounds act as substrates or modulators of these pumps. In vitro assessment of the affinity of drug candidates for multidrug resistance proteins is central to predict in vivo pharmacokinetics and drug–drug interactions. The objective of this study was to identify and characterize new substrates for these transporters. As part of a collaborative project with Life Technologies, 102 fluorescent probes were investigated in a flow cytometric screen of ABC transporters. The primary screen compared substrate efflux activity in parental cell lines with their corresponding highly expressing resistant counterparts. The fluorescent compound library included a range of excitation/emission profiles and required dual laser excitation as well as multiple fluorescence detection channels. A total of 31 substrates with active efflux in one or more pumps and practical fluorescence response ranges were identified and tested for interaction with eight known inhibitors. This screening approach provides an efficient tool for identification and characterization of new fluorescent substrates for ABCB1, ABCC1, and ABCG2.

The drug efflux pump Pgp1 in pro-inflammatory lymphocytes is a target for novel treatment strategies in COPD.

BackgroundPro-inflammatory/cytotoxic T cells (IFNγ, TNFα, granzyme B+) are increased in the peripheral circulation in COPD. NKT-like and NK cells are effector lymphocytes that we have also shown to be major sources of pro-inflammatory cytokines and granzymes. P-glycoprotein 1 (Pgp1) is a transmembrane efflux pump well characterised in drug resistant cancer cells. We hypothesized that Pgp1 would be increased in peripheral blood T, NKT-like and NK cells in patients with COPD, and that this would be accompanied by increased expression of IFNγ, TNFα and granzyme B. We further hypothesized that treatment with cyclosporine A, a Pgp1 inhibitor, would render cells more sensitive to treatment with corticosteroids.MethodsPgp1, granzyme B, IFNγ and TNFα expression were measured in peripheral blood T, NK and NKT-like cells from COPD patients and control subjects (± cyclosporine A and prednisolone) following in vitro stimulation and results correlated with uptake of efflux dye Calcein-AM using flow cytometry.ResultsThere was increased Pgp1 expression by peripheral blood T, NKT-like and NK cells co-expressing IFNγ, TNFα and granzyme B in COPD patients compared with controls (e.g. %IFNγ/Pgp1 T, NKT-like, NK for COPD (Control): 25(6), 54(27), 39(23)). There was an inverse correlation between Pgp1 expression and Calcein-AM uptake. Treatment with 2.5 ng/ml cylosporin A and10-6 M prednisolone resulted in synergistic inhibition of pro-inflammatory cytokines in Pgp1 + cells (p < 0.05 for all).ConclusionsTreatment strategies that target Pgp1 in T, NKT-like and NK cells may reduce systemic inflammatory mediators in COPD and improve patient morbidity.

Effect of the C3435T polymorphism of the multidrug resistance 1 gene on the severity of inflammatory bowel disease in Iranian Azeri Turks

Background/Aim:Multidrug resistance 1 (MDR1) gene encodes for P-glycoprotein (P-gp), a transmembrane efflux pump transferring both exogenous and endogenous substrate from the cells. In the human gastrointestinal tract, P-gp is found in high concentrations on the epithelial cells of the colon and small intestine. It is hypothesized that the expression level of MDR1 gene is related to susceptibility of both forms of inflammatory bowel disease (IBD). The aim of this study was to investigate the association of C3435T Single Nucleotide Polymorphism in IBD patients with/without clinical symptoms in Iranian Azeri Turks.Settings and Design:A total of 116 patients with IBD and 92 healthy subjects were analyzed.Materials and Methods:We investigated the distribution of MDR1 C3435T polymorphism via polymerase chain reaction – Restriction Fragment Length Polymorphism technique.Statistical Analysis Used:All statistical analyses were calculated with the SPSS for Windows 16.0. The Fisher exact test was used to test for departure from Hardy-Weinberg equilibrium of the genotype frequencies (P > 0.05).Results:The data showed that IBD patient with homozygous variant carrying MDR1 3435 T/T genotype has elevated risk for development of routine IBD clinical symptoms like Abdominal pain (P = 0.005) and chronic Diarrhea (P = 0.013) compared with MDR1 3435 C/C homozygotes who has reduced risk for development of IBD symptoms.Conclusions:Our data showed that patients with MDR1 3435 T/T are more susceptible to the development of some routine IBD clinical symptoms (P < 0.05). This study suggests a protective role for the MDR1 3435 C/C versus MDR1 3435 T/Tgenotype and C versus T allele for the progression of IBD in this cohort.