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efflux pump inhibition

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https://www.readbyqxmd.com/read/28101766/crossing-the-blood-brain-barrier-recent-advances-in-drug-delivery-to-the-brain
#1
Mayur M Patel, Bhoomika M Patel
CNS disorders are on the rise despite advancements in our understanding of their pathophysiological mechanisms. A major hurdle to the treatment of these disorders is the blood-brain barrier (BBB), which serves as an arduous janitor to protect the brain. Many drugs are being discovered for CNS disorders, which, however fail to enter the market because of their inability to cross the BBB. This is a pronounced challenge for the pharmaceutical fraternity. Hence, in addition to the discovery of novel entities and drug candidates, scientists are also developing new formulations of existing drugs for brain targeting...
January 18, 2017: CNS Drugs
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#2
Diane Borselli, Marine Blanchet, Jean-Michel Bolla, Aaron Muth, Kristen Skruber, Otto Phanstiel, Jean Michel Brunel
Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump...
January 18, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28090273/the-effects-of-berberine-and-palmatine-on-efflux-pumps-inhibition-with-different-gene-patterns-in-pseudomonas-aeruginosa-isolated-from-burn-infections
#3
Seyed Sajjad Aghayan, Hamidreza Kalalian Mogadam, Mozhgan Fazli, Davood Darban-Sarokhalil, Seyed Sajjad Khoramrooz, Fereshteh Jabalameli, Somayeh Yaslianifard, Mehdi Mirzaii
BACKGROUND: Related Multidrug Resistance (MDR) to efflux pumps is a significant problem in treating infections caused by Pseudomonas aeruginosa (P. aeruginosa). Plant compounds have been identified as Pump Inhibitors (EPIs). In the current study, the potential effect of Berberine and Palmatine as EPIs were investigated on efflux pump inhibition through focusing on different gene patterns in P. aeruginosa isolated from burn infections. METHODS: All isolates were collected and identified using the standard biochemical tests...
January 2017: Avicenna Journal of Medical Biotechnology
https://www.readbyqxmd.com/read/28088472/cholesterol-and-ergosterol-affect-the-activity-of-staphylococcus-aureus-antibiotic-efflux-pumps
#4
S R Tintino, C D M Oliveira-Tintino, F F Campina, M S Costa, R P Cruz, R L S Pereira, J C Andrade, E O Sousa, J P Siqueira-Junior, H D M Coutinho, T C Leal-Balbino, V Q Balbino
The aim of this study is to evaluate the effect of ergosterol on steroids and cholesterol efflux pumps in multidrug resistant strains of S. aureus. Were used RN4220 harboring plasmid pUL5054, which carries the gene encoding the MsrA macrolide efflux protein; and IS-58, which possesses the TetK tetracycline efflux protein; 1199B resists hydrophilic fluoroquinolones via a NorA-mediated mechanism and wild strain 1199B. The Minimal Inhibitory Concentration (MIC) was determined and the evaluation of possible inhibition of efflux pumps by reduction of MIC...
January 11, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28080217/synergistic-effects-of-tetrandrine-with-posaconazole-against-aspergillus-fumigatus
#5
Shui-Xiu Li, Yan-Jun Song, Ling Jiang, Ya-Jing Zhao, Hui Guo, Dong-Mei Li, Kun-Ju Zhu, Hong Zhang
In our earlier in vitro and in vivo studies, synergistic effects were observed when itraconazole or voriconazole were combined with tetrandrine (TET) against Aspergillus fumigatus, and the synergistic mechanism was related to inhibition of the drug efflux pump. Posaconazole (PCZ) is a broad-spectrum triazole antifungal agent used for the treatment of diverse fungal infections, including aspergillosis and candidiasis. Herein, the antifungal effects of TET are further investigated in vitro and in vivo alone or combined with PCZ against 20 clinical isolates of A...
January 12, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28068430/molecular-mimics-of-classic-p-glycoprotein-inhibitors-as-multidrug-resistance-suppressors-and-their-synergistic-effect-on-paclitaxel
#6
Moustafa E El-Araby, Abdelsattar M Omar, Maan T Khayat, Hanan A Assiri, Ahmed M Al-Abd
P-glycoprotein (Pgp) is a membrane bound efflux pump spread in a variety of tumor cells and considered as a main component of multidrug resistance (MDR) to chemotherapies. In this work, three groups of compounds (imidazolone, oxazolone and vinyl dipeptide derivatives) were synthesized aiming to develop a molecular framework that effectively suppresses MDR. When tested for their influence on Pgp activity, four compounds coded Cur1-01, Cur1-12V, Curox-1 and Curox-3 significantly decreased remaining ATP concentration indicating Pgp substrate site blocking...
2017: PloS One
https://www.readbyqxmd.com/read/28051334/glutamine-attenuates-obstructive-cholestasis-in-rats-via-farnesoid-x-receptor-mediated-regulation-of-bsep-and-mrp2
#7
Bingli Liu, Yiming Li, Hong Ji, Hongwei Lu, Hua Li, Yakun Shi
To investigate the protective effect of glutamine (Gln) against obstructive cholestasis in association with farnesoid X receptor (FXR) activation, an obstructive cholestasis model was established in male Sprague-Dawley rats by bile duct ligation (BDL). Serum biomarkers and hematoxylin plus eosin staining were used to identify the degree of hepatic injury in the rats with obstructive cholestasis after Gln treatment. Immunohistochemistry, real-time PCR, Western blot, cultured primary rat hepatocytes with FXR knockdown, and dual-luciferase reporter assay were performed to elucidate the mechanisms underlying Gln hepatoprotection...
October 5, 2016: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28044273/rnd-efflux-pump-mediated-antibiotic-resistance-in-gram-negative-bacteria-escherichia-coli-and-pseudomonas-aeruginosa-a-major-issue-worldwide
#8
REVIEW
Minakshi Puzari, Pankaj Chetia
Therapeutic failures against diseases due to resistant Gram-negative bacteria have become a major threat nowadays as confirmed by surveillance reports across the world. One of the methods of development of multidrug resistance in Escherichia coli and Pseudomonas aeruginosa is by means of RND efflux pumps. Inhibition of these pumps might help to combat the antibiotic resistance problem, for which the structure and regulation of the pumps have to be known. Moreover, judicious antibiotic use is needed to control the situation...
February 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28032595/prospective-identification-of-resistance-mechanisms-to-hsp90-inhibition-in-kras-mutant-cancer-cells
#9
Arefeh Rouhi, Christina Miller, Sarah Grasedieck, Stefanie Reinhart, Britta Stolze, Hartmut Döhner, Florian Kuchenbauer, Lars Bullinger, Stefan Fröhling, Claudia Scholl
Inhibition of the HSP90 chaperone results in depletion of many signaling proteins that drive tumorigenesis, such as downstream effectors of KRAS, the most commonly mutated human oncogene. As a consequence, several small-molecule HSP90 inhibitors are being evaluated in clinical trials as anticancer agents. To prospectively identify mechanisms through which HSP90-dependent cancer cells evade pharmacologic HSP90 blockade, we generated multiple mutant KRAS-driven cancer cell lines with acquired resistance to the purine-scaffold HSP90 inhibitor PU-H71...
December 9, 2016: Oncotarget
https://www.readbyqxmd.com/read/28029615/on-chip-bioelectric-impedance-spectroscopy-reveals-the-effect-of-p-glycoprotein-efflux-pumps-on-the-paracellular-impedance-of-tight-junctions-at-the-blood-brain-barrier
#10
Ramsey Kraya, Alexander Komin, Peter Searson
Bioelectric impedance spectroscopy was used to elucidate the influence of P-gp efflux pumps on the kinetics of tight junction down-regulation in confluent monolayers of Madine Darby Canine Kidney Epithelial Cells (MDCK) following administration of phenylarsine oxide (PAO), a molecule that inhibits protein tyrosine phosphatases (PTP) and induces matrix metalloproteinase activity. Matrix metalloproteinases (MMPs) and phosphatase inhibitors induce modification of occludin tight junction proteins critical for the proper function of the blood-brain barrier...
October 2016: IEEE Transactions on Nanobioscience
https://www.readbyqxmd.com/read/28008141/chemoresistance-and-targeted-therapies-in-ovarian-and-endometrial-cancers
#11
REVIEW
Kevin Brasseur, Nicolas Gévry, Eric Asselin
Gynecological cancers are known for being very aggressive at their advanced stages. Indeed, the survival rate of both ovarian and endometrial cancers is very low when diagnosed lately and the success rate of current chemotherapy regimens is not very efficient. One of the main reasons for this low success rate is the acquired chemoresistance of these cancers during their progression. The mechanisms responsible for this acquired chemoresistance are numerous, including efflux pumps, repair mechanisms, survival pathways (PI3K/AKT, MAPK, EGFR, mTOR, estrogen signaling) and tumor suppressors (P53 and Par-4)...
December 19, 2016: Oncotarget
https://www.readbyqxmd.com/read/28003193/fermentative-production-of-cysteine-by-pantoea-ananatis
#12
Kazuhiro Takumi, Mikhail Kharisovich Ziyatdinov, Viktor Samsonov, Gen Nonaka
: Cysteine is a commercially important amino acid; however, it lacks an efficient fermentative production method. Due to its cytotoxicity, intracellular cysteine levels are stringently controlled via several regulatory modes. Managing its toxic effects as well as understanding and deregulating the complexities of regulation are crucial for establishing the fermentative production of cysteine. The regulatory modes include feedback inhibition of key metabolic enzymes, degradation, efflux pumps, and the transcriptional regulation of biosynthetic genes by a master cysteine regulator, CysB...
December 21, 2016: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27938381/assessment-of-antibiotic-resistance-in-klebsiella-pneumoniae-exposed-to-sequential-in-vitro-antibiotic-treatments
#13
Jeongjin Kim, Ara Jo, Ekachai Chukeatirote, Juhee Ahn
BACKGROUND: Bacteria treated with different classes of antibiotics exhibit changes in susceptibility to successive antibiotic treatments. This study was designed to evaluate the influence of sequential antibiotic treatments on the development of antibiotic resistance in Klebsiella pneumoniae associated with β-lactamase and efflux pump activities. METHODS: The antibiotic susceptibility, β-lactamase activity, and efflux activity were determined in K. pneumoniae grown at 37 °C by adding initial (0 h) and second antibiotics (8 or 12 h)...
December 9, 2016: Annals of Clinical Microbiology and Antimicrobials
https://www.readbyqxmd.com/read/27908756/a-novel-curcumin-derivative-which-inhibits-p-glycoprotein-arrests-cell-cycle-and-induces-apoptosis-in-multidrug-resistance-cells
#14
Vanessa Lopes-Rodrigues, Ana Oliveira, Marta Correia-da-Silva, Madalena Pinto, Raquel T Lima, Emília Sousa, M Helena Vasconcelos
Cancer multidrug resistance (MDR) is a major limitation to the success of cancer treatment and is highly associated with the overexpression of drug efflux pumps such as P-glycoprotein (P-gp). In order to achieve more effective chemotherapeutic treatments, it is important to develop P-gp inhibitors to block/decrease its activity. Curcumin (1) is a secondary metabolite isolated from the turmeric of Curcuma longa L.. Diverse biological activities have been identified for this compound, particularly, MDR modulation in various cancer cell models...
January 15, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/27889879/plasmid-mediated-quinolone-resistance-in-enterobacteriaceae-a-systematic-review-with-a-focus-on-mediterranean-countries
#15
REVIEW
B Yanat, J-M Rodríguez-Martínez, A Touati
Quinolones are a family of synthetic broad-spectrum antimicrobial drugs. These molecules have been widely prescribed to treat various infectious diseases and have been classified into several generations based on their spectrum of activity. Quinolones inhibit bacterial DNA synthesis by interfering with the action of DNA gyrase and topoisomerase IV. Mutations in the genes encoding these targets are the most common mechanisms of high-level fluoroquinolone resistance. Moreover, three mechanisms for plasmid-mediated quinolone resistance (PMQR) have been discovered since 1998 and include Qnr proteins, the aminoglycoside acetyltransferase AAC(6')-Ib-cr, and plasmid-mediated efflux pumps QepA and OqxAB...
November 26, 2016: European Journal of Clinical Microbiology & Infectious Diseases
https://www.readbyqxmd.com/read/27879334/intrinsic-resistance-of-burkholderia-cepacia-complex-to-benzalkonium-chloride
#16
Youngbeom Ahn, Jeong Myeong Kim, Ohgew Kweon, Seong-Jae Kim, Richard C Jones, Kellie Woodling, Gonçalo Gamboa da Costa, John J LiPuma, David Hussong, Bernard S Marasa, Carl E Cerniglia
: Pharmaceutical products that are contaminated with Burkholderia cepacia complex (BCC) bacteria may pose serious consequences to vulnerable patients. Benzyldimethylalkylammonium chloride (BZK) cationic surfactants are extensively used in medical applications and have been implicated in the coselection of antimicrobial resistance. The ability of BCC to degrade BZK, tetradecyldimethylbenzylammonium chloride (C14BDMA-Cl), dodecyldimethylbenzylammonium chloride (C12BDMA-Cl), decyldimethylbenzylammonium chloride (C10BDMA-Cl), hexyldimethylbenzylammonium chloride, and benzyltrimethylammonium chloride was determined by incubation in 1/10-diluted tryptic soy broth (TSB) to determine if BCC bacteria have the ability to survive and inactivate these disinfectants...
November 22, 2016: MBio
https://www.readbyqxmd.com/read/27878697/nf%C3%AE%C2%BAbp65-transcription-factor-modulates-resistance-to-doxorubicin-through-abc-transporters-in-breast-cancer
#17
Kobra Velaei, Nasser Samadi, Sina Soltani, Balal Barazvan, Jafar Soleimani Rad
BACKGROUND: Shedding light on chemoresistance biology of breast cancer could contribute to enhance the clinical outcome. Intrinsic or acquired resistance to chemotherapy is a major problem in breast cancer treatment. METHODS AND MATERIALS: The NFκB pathway by siRNAP65 and JSH-23 as a translocational inhibitor of NFκBP65 in the doxorubicin-resistant MCF-7 (MCF-7/Dox) and MCF-7 cells was blocked. Then, the ABC transporter expression and function were assessed by real-time qRT-PCR and flow cytometry, respectively...
November 23, 2016: Breast Cancer: the Journal of the Japanese Breast Cancer Society
https://www.readbyqxmd.com/read/27872201/identification-of-chemical-compounds-that-inhibit-protein-synthesis-in-pseudomonas-aeruginosa
#18
Stephanie O Palmer, Yanmei Hu, Megan Keniry, James M Bullard
Four inhibitory compounds were identified using a poly-uridylic acid (polyU) mRNA-directed aminoacylation/translation (A/T) protein synthesis system composed of phenylalanyl-tRNA synthetases (PheRS), ribosomes, and ribosomal factors from Pseudomonas aeruginosa in an in vitro screen of a synthetic compound library. The compounds were specific for inhibition of bacterial protein synthesis. In enzymatic assays, the compounds inhibited protein synthesis with IC50 values ranging from 20 to 60 μM. Minimum inhibitory concentrations (MICs) were determined in cultures for a panel of pathogenic organisms, including Enterococcus faecalis, Escherichia coli, Haemophilus influenzae, P...
November 21, 2016: Journal of Biomolecular Screening
https://www.readbyqxmd.com/read/27871991/tumor-targeted-micelle-forming-block-copolymers-for-overcoming-of-multidrug-resistance
#19
Alena Braunová, Libor Kostka, Ladislav Sivák, Lucie Cuchalová, Zuzana Hvězdová, Richard Laga, Sergey Filippov, Peter Černoch, Michal Pechar, Olga Janoušková, Milada Šírová, Tomáš Etrych
New amphiphilic diblock polymer nanotherapeutics serving simultaneously as a drug delivery system and an inhibitor of multidrug resistance were designed, synthesized, and evaluated for their physico-chemical and biological characteristics. The amphiphilic character of the diblock polymer, containing a hydrophilic block based on the N-(2-hydroxypropyl)methacrylamide copolymer and a hydrophobic poly(propylene oxide) block (PPO), caused self-assembly into polymer micelles with an increased hydrodynamic radius (Rh of approximately 15nm) in aqueous solutions...
November 18, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/27869748/design-of-new-antibacterial-enhancers-based-on-acrb-s-structure-and-the-evaluation-of-their-antibacterial-enhancement-activity
#20
Yi Song, Rongxin Qin, Xichun Pan, Qin Ouyang, Tianyu Liu, Zhaoxia Zhai, Yingchun Chen, Bin Li, Hong Zhou
Previously, artesunate (AS) and dihydroartemisinine 7 (DHA7) were found to have antibacterial enhancement activity against Escherichia coli via inhibition of the efflux pump AcrB. However, they were only effective against E. coli standard strains. This study aimed to develop effective antibacterial enhancers based on the previous work. Our results demonstrate that 86 new antibacterial enhancers were designed via 3D-SAR and molecular docking. Among them, DHA27 had the best antibacterial enhancement activity...
November 18, 2016: International Journal of Molecular Sciences
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