Multidrug resistance

Overexpression of P-glycoprotein on fibroblast-like synoviocytes in refractory rheumatoid arthritis patients: a potential mechanism for multidrug resistance in rheumatoid arthritis treatment

Y. M. Liu, Chen, J. W., Chen, L. X., Xie, X., Mao, N., Liu, Y. M., Chen, J. W., Chen, L. X., Xie, X., and Mao, N., Overexpression of P-glycoprotein on fibroblast-like synoviocytes in refractory rheumatoid arthritis patients: a potential mechanism for multidrug resistance in rheumatoid arthritis treatment, vol. 15, p. -, 2016.

This study aims to investigate the role of P-glycoprotein (P-gp) expression level in drug resistance to disease-modifying anti-rheumatic drugs in refractory rheumatoid arthritis (RRA). We evaluated and compared the expression levels of P-gp in fibroblast-like synoviocyte (FLS) cells in patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and investigated the potential mechanism of P-gp-induced multidrug resistance in RRA. Ten patients were enrolled and divided into two groups: six in the RA group and four in the OA group.

Isolation and characterization of cancer stem cells from medulloblastoma

J. Liu, Chi, N., Zhang, J. Y., Zhu, W., Bian, Y. S., and Chen, H. G., Isolation and characterization of cancer stem cells from medulloblastoma, vol. 14, pp. 3355-3361, 2015.

Brain cancer stem cells are a subset of tumor cells present in several types of brain tumor that evade treatment regimens and are responsible for tumor recurrence. Recent reports on several tumors have suggested that Hoechst 33342 dye exclusion is a powerful technique for isolating cancer stem cell-like side population (SP) cells. In the present study, we attempted to isolate the SP cells from medulloblastoma, a malignant brain tumor in children. The tumor samples obtained were subjected to fluorescence-activated cell sorting analysis for SP cell isolation.

Mechanism of the reversal effect of mifepristone on drug resistance of the human cervical cancer cell line HeLa/MMC

H. Chen, Duan, J., and Zuo, F., Mechanism of the reversal effect of mifepristone on drug resistance of the human cervical cancer cell line HeLa/MMC, vol. 13, pp. 1288-1295, 2014.

We examined the ability of mifepristone to reverse the in vitro drug resistance of human cervical cancer cells resistant to mitomycin-C (HeLa/MMC) cells and investigated the mechanism of this effect. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the drug resistance of HeLa/MMC cells and the reversed drug resistance in vitro. Expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and glucosylceramide synthase (GCS) were measured in HeLa and HeLa/MMC cells.

Reversal effect of vitamin D on different multidrug-resistant cells

M. Yan and Nuriding, H., Reversal effect of vitamin D on different multidrug-resistant cells, vol. 13, pp. 6239-6247, 2014.

We investigated the reversal effect of vitamin D on the multidrug-resistant leukemic Jurkat/ADR and K562/ADR cell lines and conducted a preliminary investigation of its reversal mechanism. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the reversal effect of vitamin D on multidrug-resistant cells. Real-time polymerase chain reaction was used to determine the effect of vitamin D on intracellular expression of mRNA of the multidrug-resistant gene (MDRI) and the multidrug-resistance-related gene (MRP1).

Effect of MDR1 polymorphism on multidrug resistance expression in breast cancer patients

M. Taheri, Mahjoubi, F., and Omranipour, R., Effect of MDR1 polymorphism on multidrug resistance expression in breast cancer patients, vol. 9, pp. 34-40, 2010.

One of the limitations in the treatment of cancer patients with chemotherapy is the development of multidrug resistance (MDR). A well-known mechanism responsible for drug resistance is over-expression of ABC-transporter genes such as MDR1. This gene encodes p-glycoprotein (P-gp), a transmembrane glycoprotein that transports many hydrophobic substrates and anti-cancer drugs out of the cell. MDR1 gene polymorphisms could alter the expression level of P-gp and consequently result in drug resistance.

MRP1 polymorphisms (T2684C, C2007T, C2012T, and C2665T) are not associated with multidrug resistance in leukemic patients

F. Mahjoubi, Akbari, S., Montazeri, M., and Moshyri, F., MRP1 polymorphisms (T2684C, C2007T, C2012T, and C2665T) are not associated with multidrug resistance in leukemic patients, vol. 7, pp. 1369-1374, 2008.

One of the main problems in treating cancer patients is that cancer cells can develop drug resistance. Resistance to multiple anticancer drugs, so called multidrug resistance (MDR), most likely involves a nonspecific mode of resistance, through drug-efflux transporters. One of the most extensively studied genes involved in MDR is multidrug resistance protein 1 (MRP1).

Efflux as a mechanism of resistance to antimicrobials in Pseudomonas aeruginosa and related bacteria: unanswered questions

H. P. Schweizer, Efflux as a mechanism of resistance to antimicrobials in Pseudomonas aeruginosa and related bacteria: unanswered questions, vol. 2. pp. 48-62, 2003.

Pseudomonas aeruginosa is an opportunistic human pathogen exhibiting innate resistance to multiple antimicrobial agents. This intrinsic multidrug resistance is caused by synergy between a low-permeability outer membrane and expression of a number of broadly-specific multidrug efflux (Mex) systems, including MexAB-OprM and MexXY-OprM.

Molecular characterization of ABC transporter-encoding genes in Aspergillus nidulans

A. Mendes do Nascimento, Goldman, M. Helena S., and Goldman, G. H., Molecular characterization of ABC transporter-encoding genes in Aspergillus nidulans, vol. 1, pp. 337-349, 2002.

As a preliminary step towards characterizing genes encoding ATP-binding cassette (ABC) transporters that confer pleiotropic drug resistance in Aspergillus, we used a PCR-based approach to isolate four DNA fragments corresponding to different ABC type transporter genes. DNA sequencing and Southern blot analysis confirmed that they were distinct genes, which were designated abcA-D. One of these genes, abcD, was cloned and characterized. It was found to have a predicted 1,452-amino acid translation product with a calculated molecular mass of 147,467 kDa.

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