scholarly journals The human multidrug resistance-associated protein MRP is a plasma membrane drug-efflux pump.

1994 ◽  
Vol 91 (19) ◽  
pp. 8822-8826 ◽  
Author(s):  
G. J. Zaman ◽  
M. J. Flens ◽  
M. R. van Leusden ◽  
M. de Haas ◽  
H. S. Mulder ◽  
...  
2004 ◽  
Vol 48 (7) ◽  
pp. 2518-2523 ◽  
Author(s):  
Renaud Chollet ◽  
Jacqueline Chevalier ◽  
Claude Bollet ◽  
Jean-Marie Pages ◽  
Anne Davin-Regli

ABSTRACT Multidrug resistance (MDR) in Enterobacter aerogenes can be mediated by induction of MarA, which is triggered by certain antibiotics and phenolic compounds. In this study, we identified the gene encoding RamA, a 113-amino-acid regulatory protein belonging to the AraC-XylS transcriptional activator family, in the Enterobacter aerogenes ATCC 13048 type strain and in a clinical multiresistant isolate. Overexpression of RamA induced an MDR phenotype in drug-susceptible Escherichia coli JM109 and E. aerogenes ATCC 13048, as demonstrated by 2- to 16-fold-increased resistance to β-lactams, tetracycline, chloramphenicol, and quinolones, a decrease in porin production, and increased production of AcrA, a component of the AcrAB-TolC drug efflux pump. We show that RamA enhances the transcription of the marRAB operon but is also able to induce an MDR phenotype in a mar-deleted strain. We demonstrate here that RamA is a transcriptional activator of the Mar regulon and is also a self-governing activator of the MDR cascade.


1991 ◽  
Vol 98 (3) ◽  
pp. 317-322
Author(s):  
D.W. Shen ◽  
Y.G. Lu ◽  
K.V. Chin ◽  
I. Pastan ◽  
M.M. Gottesman

Multidrug resistance of human cancer cells may result from expression of P-glycoprotein, the product of the MRD1 gene, acting as an energy-dependent drug efflux pump. However, direct evidence that expression of the MDR1 gene contributes to the multidrug resistance of human liver carcinomas has not been established. In this study, we tested five cell lines derived from human hepatocellular carcinomas for sensitivity to a variety of drugs used widely as anticancer agents; these included vinblastine, doxorubicin, actinomycin D, mitomycin C, 5-fluorouracil, 6-mercaptopurine, melphalan, methotrexate, cis-platinum and etoposide (VP-16). All five hepatoma cell lines were resistant at different levels to these chemicals compared to human KB cells. Although it has been demonstrated that resistance to vinblastine, colchicine, doxorubicin and actinomycin D in human multidrug-resistant cells is associated with overexpression of P-glycoprotein, very little expression of P-glycoprotein was found in these human hepatoma cells. Neither verapamil nor quinidine, inhibitors of the drug efflux pump, were able to overcome multidrug resistance in hepatoma cells. These results indicate that the multidrug resistance phenotype in human hepatocellular carcinoma cells cannot be attributed to expression of the MDR1 gene, but that novel mechanisms may account for the resistance of these cancer cells.


2020 ◽  
Author(s):  
Yaojun Tong ◽  
Jingyu Zhang ◽  
Nuo Sun ◽  
Xiang-Ming Wang ◽  
Qi Wei ◽  
...  

2008 ◽  
Vol 28 (4) ◽  
pp. 217-228 ◽  
Author(s):  
Sneh Lata Panwar ◽  
Ritu Pasrija ◽  
Rajendra Prasad

The development of MDR (multidrug resistance) in yeast is due to a number of mechanisms. The most documented mechanism is enhanced extrusion of drugs mediated by efflux pump proteins belonging to either the ABC (ATP-binding cassette) superfamily or MFS (major facilitator superfamily). These drug-efflux pump proteins are localized on the plasma membrane, and the milieu therein affects their proper functioning. Several recent studies demonstrate that fluctuations in membrane lipid composition affect the localization and proper functioning of the MDR efflux pump proteins. Interestingly, the efflux pumps of the ABC superfamily are particularly susceptible to imbalances in membrane-raft lipid constituents. This review focuses on the importance of the membrane environment in functioning of the drug-efflux pumps and explores a correlation between MDR and membrane lipid homoeostasis.


2014 ◽  
Vol 7 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Mário Šereš ◽  
Lucia Pavlíková ◽  
Zdena Sulová ◽  
Albert Breier

Abstract P-glycoprotein is an ATP dependent drug efflux pump the expression of which is responsible for strong depression of cell sensitivities to large group of structurally unrelated substances in neoplastic cells. We found that the expression of this protein in mice leukemia cells L1210 is associated with massive remodeling of cell surface saccharides. This remodeling is consistent with the alteration of cellular contents of UDP-sugars, glycogen and glycoproteins when P-gp positive and P-gp negative L1210 cell variants were compared. The current paper is focused on bringing the state of art information about this topic.


2016 ◽  
Vol 76 (19) ◽  
pp. 5810-5821 ◽  
Author(s):  
Ramin Dubey ◽  
Andres M. Lebensohn ◽  
Zahra Bahrami-Nejad ◽  
Caleb Marceau ◽  
Magali Champion ◽  
...  

Life Sciences ◽  
1992 ◽  
Vol 51 (18) ◽  
pp. 1427-1437 ◽  
Author(s):  
Akira Tsuji ◽  
Tetsuya Terasaki ◽  
Yasushi Takabatake ◽  
Yoshiyuki Tenda ◽  
Ikumi Tamai ◽  
...  

2021 ◽  
Vol 1225 ◽  
pp. 129279
Author(s):  
Shyam Goswami ◽  
Arabinda Ghosh ◽  
Karmajyoti Borah ◽  
Anupam Mahanta ◽  
Ankur K Guha ◽  
...  

2014 ◽  
Vol 3 (6) ◽  
pp. 885-896 ◽  
Author(s):  
Thelma Ohene‐Agyei ◽  
Rumana Mowla ◽  
Taufiq Rahman ◽  
Henrietta Venter

2020 ◽  
Vol 13 (654) ◽  
pp. eaay6077
Author(s):  
Apoorva Bhattacharya ◽  
Shravanti Mukherjee ◽  
Poulami Khan ◽  
Shruti Banerjee ◽  
Apratim Dutta ◽  
...  

The high abundance of drug efflux pumps in cancer stem cells (CSCs) contributes to chemotherapy resistance. The transcriptional regulator SMAR1 suppresses CSC expansion in colorectal cancer, and increased abundance of SMAR1 is associated with better prognosis. Here, we found in breast tumors that the expression of SMAR1 was decreased in CSCs through the cooperative interaction of the pluripotency factors Oct4 and Sox2 with the histone deacetylase HDAC1. Overexpressing SMAR1 sensitized CSCs to chemotherapy through SMAR1-dependent recruitment of HDAC2 to the promoter of the gene encoding the drug efflux pump ABCG2. Treating cultured CSCs or 4T1 tumor-bearing mice with the nonsteroidal anti-inflammatory drug aspirin restored SMAR1 expression and ABCG2 repression and enhanced tumor sensitivity to doxorubicin. Our findings reveal transcriptional mechanisms regulating SMAR1 that also regulate cancer stemness and chemoresistance and suggest that, by restoring SMAR1 expression, aspirin might enhance chemotherapeutic efficacy in patients with stem-like tumors.


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