Drug transport is an important source of inter-individual variations in drug responses and is also a common site where drug-drug interactions happen. In recent years, more and more novel identified transporters have been added into the transporter super family, and this trend will continue in the future. Among the transporter members of this family, ATP-dependent efflux transporter P-glycoprotein (MDR1) and organic anion transporters (OATP) are the most important proteins involved in drug transport. MDR1 is the most well known transporter. Widely distributed in tissues such as the gastrointestinal tract, liver, kidney and so on, MDR1 plays an important role in drug absorption, distribution and excretion. Its functional genetic polymorphisms have significantly changed the pharmacokinetics of its substrate drugs, which has important clinical implications. OATP expressed in multiple tissues, and it mediated the drug excretion through the bile acid and kidney. Some genetic polymorphism of OATP genes is the cause of some abnormal drug responses.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; Drug Interactions ; genetics ; Humans ; Membrane Transport Proteins ; genetics ; metabolism ; Organic Anion Transporters ; genetics ; Pharmaceutical Preparations ; metabolism ; Polymorphism, Genetic

OBJECTIVE: To determine the effect of different heating Methods combined with neferine(Nef) on the proliferation and expressions of γH2AX and mdr-1/P-gp in MCF-7/Adr breast cancer cells. METHODS: MTT assay was used to determine block heating, water submerged heating, medium heating, and oven heating combined with 10 μg/mL Nef on adriamycin cultured MCF-7/Adr cell proliferation. The mdr-1mRNA expression was detected by real-time quantitative PCR. γH2AX and P-gp expressions were detected by Western blot. RESULTS: The absorbance values of MCF-7/Adr cells in different heating groups at 42 degree and 45 degree were significantly decreased, the mdr-1/P-gp expression was decreased, and γH2AX expression was upregulated compared with those of the 37 degree control group (all P<0.01). The absorbance values (P<0.01) and mdr-1/P-gp expression(P<0.05) were significantly lower and γH2AX expression(P<0.05) was significantly higher in the hyperthermia combined with 10 μg/mL Nef group than those of 10 μg/mL Nef group and hyperthermia group in MCF-7/Adr cells. The water submerged heating group had the lowest P-gp expression and the highest γH2AX expression among different heating groups at 42 degree and 45 degree in MCF-7/Adr cells (P<0.05). CONCLUSION Hyperthermia can increase the cell toxicity of adriamycin to multidrug resistant breast cancer cells. Hyperthermia significantly damages DNA of MCF-7/Adr cells and the higher temperature, the worse effect. Multidrug resistant breast cancer cells may respond differently to the different heating methods. Combined treatment of hyperthermia with Nef can increase the sensitivity in adriamycin chemotherapy.
ATP Binding Cassette Transporter, Subfamily B ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; metabolism ; Antibiotics, Antineoplastic ; pharmacology ; Benzylisoquinolines ; pharmacology ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Drugs, Chinese Herbal ; pharmacology ; Histones ; genetics ; metabolism ; Hot Temperature ; Humans ; RNA, Messenger ; genetics ; metabolism

OBJECTIVE: To investigate the suppression of MDR1 and P-glycoprotein induced by small interfering RNA and the restoration of sensitivity to chemotherapeutic drugs in multidrug-resistant hepatocellular carcinoma cell line Bel7402/5-Fu. METHODS: MDR1j targeted small interfering RNA duplexes were introduced into multidrug-resistant hepatocellular carcinoma cell line Bel7402/5-Fu. The suppression of MDR1 and its gene product P-glycoprotein was examined by RT-PCR and Western blot. MTT assay was performed to measure the reverse effect of small interfering RNA based on the results of IC50. Cell apoptosis was assessed by flow cytometry after various cell lines were treated with chemotherapeutic drugs. RESULTS: The overexpression of MDR1 and P-glycoprotein was suppressed efficiently by the introduction of small interfering RNA, which caused sequence-specific gene silence. The level of MDR1 in the transfected Bel7402/5-Fu cells reduced to 22.55% and P-glycoprotein to 25.49% compared with those of the controls. The apoptosis rate of Bel7402/5-Fu cells increased significantly in the siRNA group during the chemotherapy (P<0.01). Their resistance to 5-Fu was reversed by 14.88 folds, which indicated the restoration of sensitivity to drugs. CONCLUSION Small interfering RNA can inhibit MDR1 expression effective and reverse the multidrug resistance mediated by P-glycoprotein.
ATP Binding Cassette Transporter, Subfamily B ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; metabolism ; Carcinoma, Hepatocellular ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection

OBJECTIVES: Fluorouracil chemotherapeutic drugs are the classic treatment drugs of gastric cancer. But the problem of drug resistance severely limits their clinical application. This study aims to investigate whether hypoxia microenvironment affects gastric cancer resistance to 5-fluorouracil (5-FU) and discuss the changes of gene and proteins directly related to drug resistance under hypoxia condition. METHODS: Gastric cancer cells were treated with 5-FU in hypoxia/normoxic environment, and were divided into a Normoxic+5-FU group and a Hypoxia+5-FU group. The apoptosis assay was conducted by flow cytometry Annexin V/PI double staining. The real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression level of hypoxia inducible factor-1α (HIF-1α), multidrug resistance (MDR1) gene, P-glycoprotein (P-gp), and vascular endothelial growth factor (VEGF) which were related to 5-FU drug-resistance. We analyzed the effect of hypoxia on the treatment of gastric cancer with 5-FU. RESULTS: Compared with the Normoxic+5-FU group, the apoptosis of gastric cancer cells treated with 5-FU in the Hypoxia+5-FU group was significantly reduced (P<0.05), and the expression of apoptosis promoter protein caspase 8 was also decreased. Compared with the the Normoxic+5-FU group, HIF-1α mRNA expression in the Hypoxia+5-FU group was significantly increased (P<0.05), and the mRNA and protein expression levels of MDR1, P-gp and VEGF were also significantly increased (all P<0.05). The increased expression of MDR1, P-gp and VEGF had the same trend with the expression of HIF-1α. CONCLUSIONS Hypoxia is a direct influencing factor in gastric cancer resistance to 5-FU chemotherapy. Improvement of the local hypoxia microenvironment of gastric cancer may be a new idea for overcoming the resistance to 5-FU in gastric cancer.
Humans ; Fluorouracil/therapeutic use* ; Vascular Endothelial Growth Factor A/metabolism* ; Stomach Neoplasms/drug therapy* ; Drug Resistance, Multiple ; Vascular Endothelial Growth Factors/metabolism* ; Hypoxia ; ATP Binding Cassette Transporter, Subfamily B/genetics* ; ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics* ; Cell Line, Tumor ; Cell Hypoxia ; RNA, Messenger/metabolism* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Tumor Microenvironment

OBJECTIVE: To determine the effect of neferine (Nef) combined with mdr-1shRNA on the expression of mdr/P-gp in K562/A02 cell line. METHODS: MTT assay was used to observe the cell proliferation. The expression level of P-gp was determined by Western blot and the transcription of mdr-1 gene was detected by semi-quantitative RT-PCR. RESULTS: After K562/A02 cells were treated by Nef or mdr-1shRNA alone or both for 24 h, the proliferation of K562/A02 cells was significantly higher in the Nef combined with mdr-1shRNA treatment group than that of Nef or mdr-1shRNA alone group (P<0.01).The expression of mdr-1/P-gp in the Nef with mdr-1 shRNA group was significantly lower than that of Nef or mdr-1shRNA alone group. CONCLUSION Nef enhances the inhibition of mdr-1shRNA expression vector on K562/A02 cell proliferation and on P-gp protein to effectively reverse multidrug resistance induced by mdr-1 gene encoding P-gp.
ATP Binding Cassette Transporter, Subfamily B ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; metabolism ; Benzylisoquinolines ; pharmacology ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Drug Synergism ; Drugs, Chinese Herbal ; pharmacology ; Humans ; K562 Cells ; RNA, Small Interfering ; genetics ; pharmacology

OBJECTIVE: To explore the multidrug resistance (MDR) mechanism of ABC superfamily transporters in the tumor stem cells(TSC) from human brain glioma tissues. METHODS: Samples of glioma were obtained from 30 patients undergoing microsurgical tumor resection. The CD133(+) cells and CD133(-) cells from these tumor specimens were isolated by magnetic activated cell sorting(MACS). These cells were cultured, proliferated and passaged. The protein and activity expression of multidrug-resistance protein 1(MDR1) and multidrug-resistance associated protein 1(MRP1) were analyzed between CD133(+) and CD133(-) cells by immunocytochemistry and RT-PCR respectively. RESULTS: CD133(+) cells generated free floating neurosphere like brain tumor spheres(BTS) and abnormal proliferating capacity in the serum-free medium(SFM) in vitro. Three cases from glioblastoma stem cells could form BTS in the complete medium, and could be cultured for 1-3 passages. The range of positive cell proportion for MDR1 and MRP1 expression in CD133(+) cells was 18%-67% and 23%-73% respectively. The expression levels of MDR1 and MRP1 mRNA were higher in CD133(+) glioma stem cells than those in the differentiated tumor cells(TC), the protein activity was increased to 16.1 and 19.6 times respectively compared with that of TC. The protein and activity expression were positively related to the pathological grades of tumors. MDR1 or MRP1 drug resistance was not expressed in all the tumors and there was obvious correlation between MDR1 and MRP1. CONCLUSION Only a small proportion of cells in the heterogeneous glioma is CD133(+) brain tumor stem cells which display the strong capacity of self-renewing, abnormal proliferation and intrinsic multidrug resistance to traditional chemotherapy. The high expression of MDR1 and MRP1 by the CD133(+) brain tumor stem cells is one of the main mechanisms in the chemoresistance of tumors. CD133(+) brain tumor stem cells can be served as the root of multidrug resistance and key therapeutic target for glioma chemotherapy.
AC133 Antigen ; ATP Binding Cassette Transporter, Subfamily B ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; metabolism ; Antigens, CD ; immunology ; metabolism ; Brain Neoplasms ; metabolism ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Glioma ; metabolism ; Glycoproteins ; metabolism ; Humans ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; Neoplastic Stem Cells ; drug effects ; metabolism ; Peptides ; metabolism ; Spheroids, Cellular ; drug effects ; Tumor Cells, Cultured

OBJECTIVES: Nephrotic syndrome is a common disease of the urinary system. The aim of this study is to explore the effect of astragalus polysaccharides (APS) on multidrug resistance gene 1 (MDR1) and P-glycoprotein 170 (P-gp170) in adriamycin nephropathy rats and the underlying mechanisms. METHODS: A total of 72 male Wistar rats were divided into a control group, a model group, an APS low-dose group, an APS high-dose group, an APS+micro RNA (miR)-16 antagomir group and an APS+miR-16 antagomir control group, with 12 rats in each group. Urine protein (UP) was detected by urine analyzer, and serum cholesterol (CHOL), albumin (ALB), blood urea nitrogen (BUN), and creatinine (SCr) were detected by automatic biochemical analyzer; serum interleukin-6 (IL-6), IL-1β, tumor necrosis factor α (TNF-α) levels were detected by ELISA kit; the morphological changes of kidney tissues were observed by HE staining; the levels of miR-16 and MDR1 mRNA in kidney tissues were detected by real-time RT-PCR; the expression levels of NF-κB p65, p-NF-κB p65, and P-gp170 protein in kidney tissues were detected by Western blotting; and dual luciferase was used to verify the relationship between miR-16 and NF-κB. RESULTS: The renal tissue structure of rats in the control group was normal without inflammatory cell infiltration. The renal glomeruli of rats in the model group were mildly congested, capillary stenosis or occlusion, and inflammatory cell infiltration was obvious. The rats in the low-dose and high-dose APS groups had no obvious glomerular congestion, the proliferation of mesangial cells was significantly reduced, and the inflammatory cells were reduced. Compared with the high-dose APS group and the APS+miR-16 antagomir control group, there were more severe renal tissue structure damages in the APS + miR-16 antagomir group. Compared with the control group, the levels of UP, CHOL, BUN, SCr, IL-6, IL-1β, TNF-α, and MDR1 mRNA, and the protein levels of p-NF-κB p65 and P-gp170 in the model group were significantly increased (all P<0.05); the levels of ALB and miR-16 were significantly decreased (both P<0.05). Compared with the model group, the levels of UP, CHOL, BUN, SCr, IL-6, IL-1β, TNF-α, and MDR1 mRNA, and the protein levels of pNF-κB p65 and P-gp170 in the low-dose and high-dose APS groups were significant decreased (all P<0.05); and the levels of ALB and miR-16 were significantly increased (both P<0.05). Compared with APS+miR-16 antagomir control group, the UP, CHOL, BUN, SCr, IL-6, IL-1β, and TNF-α levels, MDR1 mRNA, and the protein levels of p-NF-κB p65 and P-gp170 were significantly increased (all P<0.05). The levels of ALB and miR-16 were significantly decreased in the APS+miR-16 antagomir group compared with the APS+miR-16 antagomir control group (both P<0.05). CONCLUSIONS APS can regulate the miR-16/NF-κB signaling pathway, thereby affecting the levels of MDR1 and P-gp170, and reducing the inflammation in the kidney tissues in the adriamycin nephropathy rats.
ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics* ; Animals ; Antagomirs ; Doxorubicin/toxicity* ; Genes, MDR ; Interleukin-6/metabolism* ; Kidney Diseases/genetics* ; Male ; MicroRNAs/metabolism* ; NF-kappa B/metabolism* ; Polysaccharides/pharmacology* ; RNA, Messenger ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha/metabolism*

OBJECTIVE: To analyze the mdr-1 gene promoter methylation and histone acetylation status in both MCF-7/Adr and MCF-7 cells and to preliminarily explore the epigenetic mechanism of multidrug resistance in breast cancer. METHODS: mdr-1 gene promoter methylation status of the 2 cell lines was detected by methylation-sensitive PCR. mRNA expression of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) was detected by real-time quantitative PCR. Acetylation level of histone H3 and H4 was examined by optical density assay. RESULTS: Promoter hypermethylation of mdr-1 gene was observed in MCF-7 cells whereas hypomethylation was found in MCF-7/Adr cells. Expression of DNMT1, DNMT3a, and DNMT3b mRNA in MCF-7/Adr cells significantly decreased compared with that of MCF-7 cells (P<0.05). H3 and H4 histone acetylation levels of MCF-7/Adr cells were obviously higher than those of the MCF-7 cells (P<0.01). Expression of HDAC1, HDAC2, HDAC7, and Sirtuin type 1 (SIRT1) mRNA in MCF-7/Adr cells was significantly reduced (P<0.05). CONCLUSION Hypomethylation of the promoter region of mdr-1 gene, high H3 and H4 histone acetylation, and low mRNA expression of DNMTs and HDACs may be important epigenetic factors for the development of MDR in MCF-7/ Adr cells.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; genetics ; Acetylation ; Breast Neoplasms ; pathology ; Cell Line, Tumor ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; genetics ; metabolism ; DNA Methylation ; genetics ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Epigenesis, Genetic ; Female ; Histone Deacetylases ; genetics ; metabolism ; Histones ; chemistry ; Humans ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; genetics ; metabolism

OBJECTIVE: To explore the effect of neferine on the chemotherapic sensitivity of STI 571 to K562/A02 cells and to reveal its mechanism. METHODS: MTT method was used to observe the alteration of the proliferation of K562/A02 cell line treated with STI571 alone or combined with neferine. The transcription of mdrl gene was detected by semi-quantitative RT-PCR and the P-gp expression was determined by Western blot after STI 571 alone or combined with neferine treatment. RESULTS: The cytotoxic effect of STI 571 (1 micromol/L) combined with neferine (IC50 = 3.02 micromol/L) on K562/A02 cell line was significantly higher than that of STI 571 alone (IC50 = 0.689 micromol/L). After treating with STI571 combined with neferine, the synergistic interaction on K562/A02 cells increased 4.38 folds (P < 0.05); the mdrl mRNA expression by semi-quantitative RT-PCR was significantly reduced by (45.4 +/- 2.5) % (P < 0.01); and the P-gp expression by Western blot was deregulated by 40.58% (P < 0.05). CONCLUSION Neferine significantly enhances the antineoplastic effect of STI 571 on K562/A02 cells by reducing mdrl mRNA transcription and blocking P-gp expression.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; biosynthesis ; genetics ; Antineoplastic Agents, Phytogenic ; pharmacology ; Benzamides ; Benzylisoquinolines ; pharmacology ; Cell Proliferation ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Drug Synergism ; Humans ; Imatinib Mesylate ; K562 Cells ; Piperazines ; pharmacology ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Pyrimidines ; pharmacology

Currently, chemoresistance seriously attenuates the curative outcome of liver cancer. The purpose of our work was to investigate the influence of 6-shogaol on the inhibition of 5-fluorouracil (5-FU) in liver cancer. The cell viability of cancer cells was determined by MTT assay. Liver cancer cell apoptosis and the cell cycle were examined utilizing flow cytometry. Moreover, qRT-PCR and western blotting was used to analyse the mRNA and protein expression levels, respectively. Immunohistochemistry assays were used to examine multidrug resistance protein 1 (MRP1) expression in tumour tissues. In liver cancer cells, we found that 6-shogaol-5-FU combination treatment inhibited cell viability, facilitated G0/G1 cell cycle arrest, and accelerated apoptosis compared with 6-shogaol or 5-FU treatment alone. In cancer cells cotreated with 6-shogaol and 5-FU, AKT/mTOR pathway- and cell cycle-related protein expression levels were inhibited, and MRP1 expression was downregulated. AKT activation or MRP1 increase reversed the influence of combination treatment on liver cancer cell viability, apoptosis and cell cycle arrest. The inhibition of AKT activation to the anticancer effect of 6-shogaol-5-FU could be reversed by MRP1 silencing. Moreover, our results showed that 6-shogaol-5-FU combination treatment notably inhibited tumour growth in vivo. In summary, our data demonstrated that 6-shogaol contributed to the curative outcome of 5-FU in liver cancer by inhibiting the AKT/mTOR/MRP1 signalling pathway.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Apoptosis ; Catechols ; Cell Cycle ; Cell Cycle Checkpoints ; Cell Line, Tumor ; Cell Proliferation ; Drug Resistance, Neoplasm ; Fluorouracil/pharmacology* ; Humans ; Liver Neoplasms/genetics* ; Multidrug Resistance-Associated Proteins ; Proto-Oncogene Proteins c-akt/metabolism* ; TOR Serine-Threonine Kinases/metabolism*