scholarly journals RND-type drug efflux pumps from Gram-negative bacteria: molecular mechanism and inhibition

2015 ◽  
Vol 06 ◽  
Author(s):  
Henrietta Venter ◽  
Rumana Mowla ◽  
Thelma Ohene-Agyei ◽  
Shutao Ma
Keyword(s):  
Molecular Mechanism ◽  
Efflux Pumps ◽  
Gram Negative Bacteria ◽  
Drug Efflux ◽  
Gram Negative ◽  
Drug Efflux Pumps

The Role of NIR Fluorescence in MDR Cancer Treatment: From Targeted Imaging to Phototherapy

2020 ◽  
Vol 27 (33) ◽  
pp. 5510-5529
Author(s):  
Zengtao Wang ◽  
Qingqing Meng ◽  
Shaoshun Li
Keyword(s):  
Cancer Treatment ◽  
Near Infrared ◽  
Combined Therapy ◽  
Efflux Pumps ◽  
Cross Resistance ◽  
Great Promise ◽  
Drug Efflux ◽  
Nir Dyes ◽  
Nir Imaging ◽  
Drug Efflux Pumps

Background: Multidrug Resistance (MDR) is defined as a cross-resistance of cancer cells to various chemotherapeutics and has been demonstrated to correlate with drug efflux pumps. Visualization of drug efflux pumps is useful to pre-select patients who may be insensitive to chemotherapy, thus preventing patients from unnecessary treatment. Near-Infrared (NIR) imaging is an attractive approach to monitoring MDR due to its low tissue autofluorescence and deep tissue penetration. Molecular NIR imaging of MDR cancers requires stable probes targeting biomarkers with high specificity and affinity. Objective: This article aims to provide a concise review of novel NIR probes and their applications in MDR cancer treatment. Results: Recently, extensive research has been performed to develop novel NIR probes and several strategies display great promise. These strategies include chemical conjugation between NIR dyes and ligands targeting MDR-associated biomarkers, native NIR dyes with inherent targeting ability, activatable NIR probes as well as NIR dyes loaded nanoparticles. Moreover, NIR probes have been widely employed for photothermal and photodynamic therapy in cancer treatment, which combine with other modalities to overcome MDR. With the rapid advancing of nanotechnology, various nanoparticles are incorporated with NIR dyes to provide multifunctional platforms for controlled drug delivery and combined therapy to combat MDR. The construction of these probes for MDR cancers targeted NIR imaging and phototherapy will be discussed. Multimodal nanoscale platform which integrates MDR monitoring and combined therapy will also be encompassed. Conclusion: We believe these NIR probes project a promising approach for diagnosis and therapy of MDR cancers, thus holding great potential to reach clinical settings in cancer treatment.

Efflux Pumps of Gram-Negative Bacteria, a New Target for New Molecules

2010 ◽  
Vol 999 (999) ◽  
pp. 1-10
Author(s):  
Jean-Marie Pages ◽  
Sandrine Alibert-Franco ◽  
Abdallah Mahamoud ◽  
Jean-Michel Bolla ◽  
Anne Davin-Regli ◽  
...  
Keyword(s):  
Efflux Pumps ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals A Simple Method for Assessment of MDR Bacteria for Over-Expressed Efflux Pumps

2013 ◽  
Vol 7 (1) ◽  
pp. 72-82 ◽  
Author(s):  
Marta Martins ◽  
Matthew P McCusker ◽  
Miguel Viveiros ◽  
Isabel Couto ◽  
Séamus Fanning ◽  
...  
Keyword(s):  
Ethidium Bromide ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Outer Cell ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Topoisomerase Iv ◽  
Simple Method ◽  
Gram Negative ◽  
Over Expression

It is known that bacteria showing a multi-drug resistance phenotype use several mechanisms to overcome the action of antibiotics. As a result, this phenotype can be a result of several mechanisms or a combination of thereof. The main mechanisms of antibiotic resistance are: mutations in target genes (such as DNA gyrase and topoisomerase IV); over-expression of efflux pumps; changes in the cell envelope; down regulation of membrane porins, and modified lipopolysaccharide component of the outer cell membrane (in the case of Gram-negative bacteria). In addition, adaptation to the environment, such as quorum sensing and biofilm formation can also contribute to bacterial persistence. Due to the rapid emergence and spread of bacterial isolates showing resistance to several classes of antibiotics, methods that can rapidly and efficiently identify isolates whose resistance is due to active efflux have been developed. However, there is still a need for faster and more accurate methodologies. Conventional methods that evaluate bacterial efflux pump activity in liquid systems are available. However, these methods usually use common efflux pump substrates, such as ethidium bromide or radioactive antibiotics and therefore, require specialized instrumentation, which is not available in all laboratories. In this review, we will report the results obtained with the Ethidium Bromide-agar Cartwheel method. This is an easy, instrument-free, agar based method that has been modified to afford the simultaneous evaluation of as many as twelve bacterial strains. Due to its simplicity it can be applied to large collections of bacteria to rapidly screen for multi-drug resistant isolates that show an over-expression of their efflux systems. The principle of the method is simple and relies on the ability of the bacteria to expel a fluorescent molecule that is substrate for most efflux pumps, ethidium bromide. In this approach, the higher the concentration of ethidium bromide required to produce fluorescence of the bacterial mass, the greater the efflux capacity of the bacterial cells. We have tested and applied this method to a large number of Gram-positive and Gram-negative bacteria to detect efflux activity among these multi-drug resistant isolates. The presumptive efflux activity detected by the Ethidium Bromide-agar Cartwheel method was subsequently confirmed by the determination of the minimum inhibitory concentration for several antibiotics in the presence and absence of known efflux pump inhibitors.

scholarly journals Interdependence of multi-drug efflux pumps and quorum sensing systems in Pseudomonas aeruginosa

2014 ◽  
Vol 21 ◽  
pp. 92
Author(s):  
K. Ganguly ◽  
J.L. Phillips ◽  
M.S. Wren ◽  
P.E. Pardington ◽  
S. Gnanakaran ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Efflux Pumps ◽  
Drug Efflux ◽  
Sensing Systems ◽  
Drug Efflux Pumps

The distribution of drug-efflux pumps, P-gp, BCRP, MRP1 and MRP2, in the normal blood–testis barrier and in primary testicular tumours

2004 ◽  
Vol 40 (14) ◽  
pp. 2064-2070 ◽  
Author(s):  
J. Bart ◽  
H. Hollema ◽  
H.J.M. Groen ◽  
E.G.E. de Vries ◽  
N.H. Hendrikse ◽  
...  
Keyword(s):  
Efflux Pumps ◽  
Normal Blood ◽  
Drug Efflux ◽  
Testicular Tumours ◽  
Drug Efflux Pumps ◽  
Blood Testis Barrier

Antimicrobial Drug Efflux Pumps in Burkholderia

2016 ◽  
pp. 417-438 ◽  
Author(s):  
Viola Camilla Scoffone ◽  
Tom Coenye ◽  
Giovanna Riccardi ◽  
Silvia Buroni
Keyword(s):  
Efflux Pumps ◽  
Antimicrobial Drug ◽  
Drug Efflux ◽  
Drug Efflux Pumps
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