OBJECTIVES: Hypoxia can alter the oral bioavailability of drugs, including various substrates (drugs) of P-glycoprotein (P-gp), suggesting that hypoxia may affect the function of P-gp in intestinal epithelial cells. Currently, Caco-2 monolayer model is the classic model for studying the function of intestinal epithelial P-gp. This study combines the Caco-2 monolayer model with hypoxia to investigate the effects of hypoxia on the expression and function of P-gp in Caco-2 cells, which helps to elucidate the mechanism of changes in drug transport on intestinal epithelial cells in high-altitude hypoxia environment. METHODS: Normally cultured Caco-2 cells were cultured in 1% oxygen concentration for 24, 48, and 72 h, respectively. After the extraction of the membrane proteins, the levels of P-gp were measured by Western blotting. The hypoxia time, with the most significant change of P-gp expression, was selected as the subsequent study condition. After culturing Caco-2 cells in transwell cells for 21 days and establishing a Caco-2 monolayer model, they were divided into a normoxic control group and a hypoxic group. The normoxic control group was continuously cultured in normal condition for 72 h, while the hypoxic group was incubated for 72 h in 1% oxygen concentration. The integrity and polarability of Caco-2 cells monolayer were evaluated by transepithelial electrical resistance (TEER), apparent permeability (Papp) of lucifer yellow, the activity of alkaline phosphatase (AKP), and microvilli morphology and tight junction structure under transmission electron microscope. Then, the Papp of rhodamine 123 (Rh123), a kind of P-gp specific substrate, was detected and the efflux rate was calculated. The Caco-2 cell monolayer, culturing at plastic flasks, was incubated for 72 h in 1% oxygen concentration, the expression level of P-gp was detected. RESULTS: P-gp was decreased in Caco-2 cells with 1% oxygen concentration, especially the duration of 72 h (P<0.01). In hypoxic group, the TEER of monolayer was more than 400 Ω·cm², the Papp of lucifer yellow was less than 5×10^-7 cm/s, and the ratio of AKP activity between apical side and basal side was greater than 3. The establishment of Caco-2 monolayer model was successful, and hypoxia treatment did not affect the integrity and polarization state of the model. Compared with the normoxic control group, the efflux rate of Rh123 was significantly reduced in Caco-2 cell monolayer of the hypoxic group (P<0.01). Hypoxia reduced the expression of P-gp in Caco-2 cell monolayer (P<0.01). CONCLUSIONS Hypoxia inhibits P-gp function in Caco-2 cells, which may be related to the decreased P-gp level.
Humans ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Caco-2 Cells ; ATP Binding Cassette Transporter, Subfamily B ; Hypoxia ; Oxygen

OBJECTIVE: To investigate the effect of ursane triterpenoids 3β,19α-dihydroxyursu-12-ene-23,28-dicarboxylic acid (Rotundioic acid, RA) on the sensitivity of adriamycin-resistant K562 cells (K562/ADM Cell) anti-tumor drug, and to explore the effect and mechanism of RA on the multidrug resistance of K562/ADM cells. METHODS: CCK-8 method was used to detect the effect of RA on the sensitivity of K562 cells and K562/ADM cells to anti-tumor drug. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression level of mRNA and the protein in K562 and K562/ADM cells, and the effect of RA on the expression of MDR1 mRNA and P-gp in K562/ADM cells was also detected; Western blot was used to detect the expression of p-JNK, p-p38 and p-ERK1/2 in K562/ADM cells. RESULTS: RA could increased the sensitivity of K562/ADM cells to adriamycin(the reversal factor was 1.61 times), the difference showed statistically significantly (P<0.05); the resistance factor of K562/ADM to ADM was 41.76 times. The expression of MDR1 mRNA in K562 cells was extremely low, and the protein product P-glycoprotein (P-gp) was almost not expressed; MDR1 mRNA and P-gp in K562/ADM cells were highly expressed; RA could down-regulate the expression levels of MDR1 and P-gp in K562/ADM cells. In addition, RA could upregulate the phosphorylation levels of p38 and ERK1/2 in K562/ADM cells, but it has no effect on the expression of p-JNK. CONCLUSION RA may participate in the regulation of MAPK signaling pathway by upregulating the expression levels of p-p38 and p-ERK1/2 in K562/ADM cells, and thus inhibit the transcription and translation levels of MDR1, and finally reverse the multidrug resistance of leukemia cells.
ATP Binding Cassette Transporter, Subfamily B ; ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; K562 Cells

OBJECTIVE: To study the effect of MDR1 (P-gp) and ABCG2 on the drug resistance in Hep 2 cells. METHOD: Flow cytometry was used to detect the variations of the antitumor drugs accumulation and discharging, and activity variations when MDR1 and ABCG2 inhibitors were used in Hep-2. RESULT: The accumulation and discharging of mitoxantrone was significantly higher than the control group when ABCG2 inhibitor FTC was used in Hep-2 (P<0. 05). In contrast, P-gp did not appear similar case; To the mitoxantrone and cisplatin, there was no statistical correlation about activity of Hep-2 between P-gp or ABCG2 antagonist and the control; To the doxorubicin, combining FTC and P-gp, the activity of Hep-2 was higher than the control and difference was significant (P<. 05), In contrast, FTC and P-gp did not appear similar case when used alone; To the 5-FU, when PGP used, the activity of Hep-2 was higher than that in the control and difference was significant (P<0. 05), In con- trast, FTC and FTC+P-gp did not appear similar case; To the paclitaxel, when P-gp or FTC+P-gp used, the activity of Hep-2 was higher than that in the control and difference was significant(P<0. 05). CONCLUSION ABCG2 may lead to drug resistance mainly by changing the ability of cell in accumulating and discharging chemotherapy drugs. P-gp has other way. P-gp and ABCG2 play different roles in different drug resistance.
ATP Binding Cassette Transporter, Subfamily B ; metabolism ; ATP Binding Cassette Transporter, Subfamily G, Member 2 ; ATP-Binding Cassette Transporters ; metabolism ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; Humans ; Mitoxantrone ; pharmacology ; Neoplasm Proteins ; metabolism ; Paclitaxel ; pharmacology

OBJECTIVE: To explore the genetic etiology for a pedigree affected with progressive familial intrahepatic cholestasis (PFIC). METHODS: Target sequence capture and next generation sequencing (NGS) were applied for the proband. PCR and Sanger sequencing were used to verify the suspected mutation in his sister with similar symptoms and his parents. RESULTS: The proband and his sister manifested after birth with symptoms including jaundice, pruritus and developmental retardation. NGS has identified compound heterozygous mutations of ABCB11 gene, which encodes bile salt export pump protein (BSEP), namely c.2494C>T (p.Arg832Cys) and c.3223C>T (p.Gln1075*), in the proband, which were inherited from his father and mother respectively. His sister carried the same compound mutations. CONCLUSION Based on the phenotype and genetic testing, the patients were diagnosed as PFIC2 caused by mutation of the ABCB11 gene. The c.3223C>T is a novel nonsense mutation which may cause premature termination of translation. Above results have enriched the spectrum of ABCB11 mutations and provided new evidence for the molecular basis of PFIC, which also facilitated genetic counseling for this pedigree.
ATP Binding Cassette Transporter, Subfamily B, Member 11 ; genetics ; ATP-Binding Cassette Transporters ; Cholestasis, Intrahepatic ; genetics ; Female ; Genetic Testing ; Humans ; Male ; Mutation ; Pedigree ; Phenotype

OBJECTIVE: To study the association between the expression of the MDR3 gene and the pathogenesis of parenteral nutrition-associated cholestasis (PNAC) in preterm infants. METHODS: Among the preterm infants who were admitted to the hospital from June 2011 to November 2017 and received parenteral nutrition for more than 14 days, 80 who did not develop PNAC were enrolled as non-PNAC group, and 76 who developed PNAC were enrolled as PNAC group. On days 1, 14, 30, 60 and 90 after birth, serum hepatobiliary biochemical parameters [alanine aminotransferase (ALT), total bilirubin (TBil), direct bilirubin (DBil), total bile acid (TBA) and gamma-glutamyl transpeptidase (γ-GT)], fibrosis indices [hyaluronic acid, laminin, procollagen III N-terminal peptide and type IV collagen] and clinical manifestations were observed. Real-time quantitative PCR was used to measure the mRNA expression of MDR3 in both groups, and the correlation between the mRNA expression of MDR3 and serum hepatobiliary biochemical parameters was analyzed. RESULTS: In the PNAC group, serum levels of hepatobiliary biochemical parameters and fibrosis indices increased on day 14 after birth and reached the peak on day 30 after birth, followed by a reduction on day 60 after birth. On days 14, 30, 60 and 90 after birth, the PNAC group had significantly higher serum levels of hepatobiliary biochemical parameters and fibrosis indices than the non-PNAC group (P<0.05). The PNAC group had higher relative mRNA expression of MDR3 in peripheral blood cells than the non-PNAC group (P<0.05). In the PNAC group, the relative mRNA expression of MDR3 in peripheral blood cells was negatively correlated with serum levels of hepatobiliary biochemical parameters (ALT, TBil, DBil, TBA and γ-GT) (P<0.001). CONCLUSIONS High mRNA expression of MDR3 in preterm infants may be associated with the development of PNAC, and further studies are needed to identify the mechanism.
ATP Binding Cassette Transporter, Subfamily B ; genetics ; Cholestasis ; genetics ; Humans ; Infant, Newborn ; Infant, Premature ; Parenteral Nutrition ; RNA, Messenger

Drug metabolism will change significantly during inflammation, including the reduction of expression and activity of many drug metabolizing enzymes and transporters. Body would release a series of inflammatory cytokines which can regulate drug metabolizing enzymes. Recent studies have revealed that drug transporters are also regulated by the cytokines with obvious species difference. Mechanism studies show that several transcription factors play important roles during the signal pathways of regulation. This review focuses on the progress in the regulation of drug transporters during inflammation.
ATP Binding Cassette Subfamily B Member 11 ; ATP Binding Cassette Transporter, Sub-Family B ; metabolism ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; metabolism ; Animals ; Biological Transport ; Humans ; Inflammation ; metabolism ; Membrane Transport Proteins ; metabolism ; Multidrug Resistance-Associated Proteins ; metabolism ; Neoplasm Proteins ; metabolism ; Organic Anion Transporters ; metabolism ; Organic Cation Transport Proteins ; metabolism ; Signal Transduction

<b>OBJECTIVEb>To establish the adriamycin(ADR)-resistant ALL cell lines and to investigate their drug-resistan mechanisms.

<b>METHODSb>The drug-resistant cell lines SUP-B15/ADR and RS4;11/ADR were derived by exposing the parental cells [SUP-B15(Ph) and RS4;11(Ph)] to the ascending concentrations of ADR. The cell viability was detected by CCK-8 method. The expression of P-gp was examined by Western blot, and RT-qPCR was performed to detect the expression of MDR1.

<b>RESULTSb>The drug-resistant cell lines SUP-B15/ADR and RS4;11/ADR were successfully established, their resistance indexes were 14.088±0.763 and 10.473±1.024, respectively. After the cryopreserved SUP-B15/ADR and RS4;11/ADR cells were resuscitated, their survival rates were 88.4±1.2% and 89.3±1.6% respectively, while their resistance indexes were 13.976±0.967 and 10.342±0.846 respectively (P>0.05). When the drug-resistant cells were cultured in the medium without ADR for 1 month, their drug-resistance indexes dropped down to 12.893±1.255 and 9.327±0.321 respectively(P<0.05). Drug-resistant cell lines had the cross-resistance to cytarabine and etoposide. The expression of P-gp and MDR1 in drug-resistant cells was significantly higher than that in wild-type cells.

<b>CONCLUSIONb>Two drug-resistant ALL cell lines have been successfully established by exposing to the ascending concentration of ADR. The over-expression of MDR1 and P-gp in drug-resistant cells may be one of the mechanisms underlying the drug resistance.

OBJECTIVE: To analyze the relation between the signle nucleotide polymorphisms (SNP) of CYP3A5 gene and MDR1 gene loci and the risk of cytogenetic relapse in chronic myeloid leukemia (CML). METHODS: The clinical data of 90 patients with CML treated with imatinib in our hospital were collected.The patients were divided into 2 groups: non-relapse and relapse according to relapse and non-relapse, then the relation between the SNP of CYP3A5 gene and MRD1 gene loci and the risk of cytogenetic relapse in CML patients. RESULTS: The grouping result showed that the patients with non cytogenetic relapse accounted for 41 cases those were enrolled in non-relapse group, and patient-with cytogenetic relapse accounted for 49 cases those were enrolled in relapse group. The follow-up time was 36 months. The detection showed that the incidence of cytogenetic relapse in the patients with CC genotype was significantly higher than that in the patients with TT+CT genotype of C3435T and C1236T at MDR1 gene loci (P<0.05).Compared with the patients with CT+CC genotype in C3435T locus of MDR1 gene, the rate of cytogenetic relapse in the patients with TT genotype decreased significantly (P<0.05). Compared with patients with CT+CC phemotype of C3435T in MDR1 gene locus, the non-relapse survival time of TT genotypes was significantly prolonged (P<0.05). Compared with non-relapse group, the incidence of neutropenia (29.27% vs 71.43%) and blood toxicity (39.02% vs 61.22%) in the relapse group increased significantly (P<0.05). The imatinib dose (OR=2 95, 95% CI:1.37~7.76) and the C3435T genotype in MDR1 genes (OR=0.09, 95% CI:0.05~0.72) were the factors affecting the cytogenetic relapse of the patients with CML (both P<0.05). CONCLUSION The therapeutic dose of imatinib and the C3435T and C1236T genotypes in MDR1 gene have a certain effect on the cytogenetic relapse of CML patients. C3435T genotypes in the.MDR1 gene showed a certain predictive value for evaluating the risk of cytogenetic relapse, which can be used as a clinical biomarker.
ATP Binding Cassette Transporter, Subfamily B ; genetics ; Cytochrome P-450 CYP3A ; genetics ; Genotype ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Polymorphism, Single Nucleotide ; Recurrence

OBJECTIVES: To investigate the effect of adriamycin (ADM), idelalisib or ADM and their combination on cell proliferation and intracellular concentration of ADM, and to explore the reversal effect of idelalisib on drug resistance to ADM. METHODS: The K562 and K562/ADM cells were respectively treated with ADM and idelalisib at different concentrations. The 50% inhibitory concentration (IC RESULTS: The cell survival rates were significantly decreased in a dose-dependent manner when the cells were treated with different doses of ADM (0.001-10.000 mg/L ). The IC CONCLUSIONS Idelalisib exerts effect on inhibition of the proliferation in myeloid leukemia K562 and K562/ADM cells, which may partially reverse the drug resistance of K562/ADM cells to ADM. The mechanisms for the effect of idelalisib may be related to increasing the accumulation of ADM and inducing the cell apoptosis in the K562 and K562/ADM cells.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Cell Proliferation ; Doxorubicin/pharmacology* ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Humans ; K562 Cells ; Leukemia, Myeloid ; Purines ; Quinazolinones

Objective To explore the role of multidrug resistance gene-1(MDR1)gene in methotrexate(MTX)resistance in patients with rheumatoid arthritis(RA).Methods Fibroblast-like synoviocytes(FLS)from RA patients were infected with recombinant adenovirus Ad-EGFP-MDR1 to obtain MDR1 over-expressed RA FLS.The transcription level of MDR1 gene and the expression level of its coding product P-glycoprotein(P-gp) rotein were detected by real-time PCR and Western blot analysis.The efflux function was verified by rhodamine 123 efflux assay.The resistance to MTX was detected by MTT assay.Results RA FLS were infected with recombinant adenovirus Ad-EGFP-MDR1;72 hours later,the particles size in MDR1 over-expressed RA FLS increased,the cell volume became larger,and the growth rate decreased.The transcription level of MDR1(1.4325±0.3924 0.0650±0.0070;=6.035,=0.004),the expression level of P-gp protein(1.8667±0.2857 0.9367±0.0551;=5.536,=0.005),and the ability of extracellular rhodamine 123(979.43±196.81 1680.06±147.04;=-4.940,=0.008) in MDR1 over-expressed RA FLS were significantly higher than those of negative virus control RA-FLS,and the survival rate of MDR1 over-expressed RA FLS was significantly increased at each concentration of MTX(<0.05).Conclusion The high expression of MDR1 can affect the efflux ability to MTX by up-regulating the expression of P-gp,thus enhancing the drug resistance to MTX in RA FLS.
ATP Binding Cassette Transporter, Subfamily B ; genetics ; Arthritis, Rheumatoid ; drug therapy ; genetics ; Cells, Cultured ; Drug Resistance ; Fibroblasts ; drug effects ; Humans ; Methotrexate ; pharmacology ; Synovial Membrane ; cytology