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 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

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

ATP Binding Cassette Subfamily B Member 11 ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; physiology ; ATP-Binding Cassette, Sub-Family B, Member 1 ; physiology ; Animals ; Bile ; metabolism ; Biliary Tract ; physiology ; Drug Interactions ; Drug Resistance, Multiple ; Humans ; Liver ; physiology ; Multidrug Resistance-Associated Proteins ; physiology ; Neoplasm Proteins ; physiology ; Organic Anion Transporters ; physiology ; Organic Anion Transporters, Sodium-Dependent ; physiology ; Organic Cation Transport Proteins ; physiology ; Symporters ; physiology

OBJECTIVE: To investigate evodiamine (EVO)-induced hepatotoxicity and the underlying mechanism. METHODS: HepG2 cells were treated with EVO (0.04-25 μmol/L) for different time intervals, and the cell survival rate was examined by cell counting kit-8 (CCK-8) method. After HepG2 cells were treated with EVO (0.2, 1 and 5 μmol/L) for 48 h, the alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) activities and total bilirubin (TBIL) content of supernatant were detected. A multifunctional microplate reader was used to detect the intracellular superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in HepG2 cells to evaluate the level of cell lipid peroxidation damage. The interactions between EVO and apoptosis, autophagy or ferroptosis-associated proteins were simulated by molecular docking. The HepG2 cells were stained by mitochondrial membrane potential (MMP) fluorescent probe (JC-10) and annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI), and MMP and apoptosis in HepG2 cells were detected by flow cytometry. The protein expression levels of caspase-9, caspase-3, bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2) were detected by Western blot. RESULTS: The cell survival rate was significantly reduced after the HepG2 cells were exposed to EVO (0.04-25 μmol/L) in a time- and dose-dependent manner. The half maximal inhibitory concentration (IC50) of the HepG2 cells treated with EVO for 24, 48 and 72 h were 85.3, 6.6 and 4.7 μmol/L, respectively. After exposure to EVO (0.2, 1 and 5 μmol/L) for 48 h, the ALT, AST, LDH, ALP activities and TBIL content in the HepG2 cell culture supernatant, and the MDA content in the cells were increased, and SOD enzyme activity was decreased. Molecular docking results showed that EVO interacted with apoptosis-associated proteins (caspase-9 and caspase-3) better. JC-10 and Annexin V-FITC/PI staining assays demonstrated that EVO could decrease MMP and promote apoptosis in the HepG2 cells. Western blot results indicated that the protein expressions of cleaved caspase-9 and cleaved caspase-3 were upregulated in the HepG2 cell treated with EVO for 48 h. In contrast, the protein expressions of pro-caspase-3, BSEP and MRP2 were downregulated. CONCLUSION These results suggested that 0.2, 1 and 5 μmol/L EVO had the potential hepatotoxicity, and the possible mechanism involved lipid peroxidation damage, cell apoptosis, and cholestasis.
ATP Binding Cassette Transporter, Subfamily B, Member 11 ; Apoptosis ; Caspase 3 ; Caspase 9 ; Cholestasis ; Hep G2 Cells/drug effects* ; Humans ; Lipid Peroxidation ; Liver/drug effects* ; Molecular Docking Simulation ; Multidrug Resistance-Associated Protein 2 ; Quinazolines/toxicity*

OBJECTIVE: To investigate the association between transporter associated with antigen processing 1 (TAP1) rs1057141 and rs1135216 gene polymorphisms and predisposition to allergic rhinitis (AR) in Xinjiang Han people. METHOD: A case control study was conducted. The region of the TAP1 * rs1057141 and rs1135216 was studied in 150 Xinjiang Han people with allergic rhinitis and 150 normal controls by using SNaPshot system, and these data were compared with other ethics groups in the world according to the NCBI gene bank. RESULT: The genotypes distribution of the group were in the Hardy-Weinberg equilibrium(P>0.05). The frequencies of three genotypes(G/G, G/A, A/A) of TAP1 * rs1057141 were 4.00%, 30.00%, 66.00% in controls and 2.70%, 33.30%, 64.00% in AR groups , which showed no difference (P>0.05). The frequencies of three genotypes (G/G,G/A,A/A) of TAP1 * rs1135216 were 2.0%, 28.7%, 69.3% in controls and 1.30%, 27.30%, 71.40% in AR groups, which showed no difference either (P>0.05). According to the NCBI database, there was difference between Xinjiang Han people and other ethnics in the world. CONCLUSION Lacking association was found between the mutation of TAP1 * rs1057141, rs1135216 gene G allele and allergic rhinitis in the Xinjiang Han people. Maybe TAP1 * rs1057141, rs1135216 were not susceptibility genes to AR. And apparent differences existed in TAP1 gene polymorphisms between Xinjiang Han people and other ethnic groups in the world.
ATP Binding Cassette Transporter, Subfamily B, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Alleles ; Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; Rhinitis, Allergic ; Rhinitis, Allergic, Perennial ; epidemiology ; genetics