OBJECTIVETo elucidate the effect of the low dosage endotoxin damage on the expression of the organic cation transporter 1 (OCT1) mRNA in hepatocytes and make an approach to the probable effect of dexamethasone on the expression of the OCT1 mRNA after endotoxin damage.

METHODS(1) The endotoxin damage model was established in rats; (2) The change of the expression of OCT1 mRNA in hepatocytes after endotoxin damage was observed by in situ hybridization method; (3) The change of the ultra structure of hepatocytes after endotoxin damage was observed with the electron microscope; (4) Dexamethasone was injected intraperitoneally before endotoxin damage in order to determine the influence of dexamethasone on the expression of OCT1 mRNA after endotoxin treatment.

RESULTSThe expression of OCT1 mRNA decreased until 16 hours (0.5745+/-0.012, P<0.01) after endotoxin treatment and then increased after this time point, which was still lower than the normal control; The expression of OCT1 mRNA in rat hepatocytes increased at each time point after endotoxin damage with dexamethasone treatment. It was highest at 16 hours (0.6327+/-0.007, P<0.01) after endotoxin damage, but it was still lower than that of the normal control.

CONCLUSIONEndotoxin could repress the expression of OCT1 mRNA even before the low dosage endotoxin inducing serious damage to the structure of hepatocytes; Dexamethasone could not induce the expression of OCT1 mRNA in normal hepatocytes, but could lighten the repression of endotoxin on the expression of OCT1 mRNA. And then the expression of OCT1 mRNA could increase at some extent after endotoxin damage with dexamethasone treatment.

Animals ; Dexamethasone ; pharmacology ; Endotoxins ; toxicity ; Male ; Organic Cation Transporter 1 ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar

Organic ion transporters are expressed in various tissues that transport endogenous and exogenous compounds including their metabolites. There are organic anion transporter (OAT), organic cation transporter (OCT), organic anion transporter like protein (OATLP) and organic cation transporter like (OCTL). Considering the variety of charged organic ionic compounds, the existence of numerous isoforms of organic ion transporters can be assumed. In the present study, we have searched for a new isoform in the expressed sequence tag (EST) database using human organic anion transporter 4 (hOAT4) amino acid sequence as a "query". We found a candidate clone (BC021449) from the mouse kidney cDNA library. This clone was identified as an ortholog of ORCTL3 or OCTL-1. The mOCTL1 cDNA consists of 2016 base pairs encoding 551 amino acid residues with 12 putative transmembrane domains. The deduced amino acid sequence of mOCTL1 showed 35 to 40% identity to those of the other members of the OATs and OCTs. According to the tissue distribution, examined by Northern blot analysis, about a 2.4-kb transcript of mOCTL1 was observed in the kidney. About a 90-kDa band was detected when Western blot analysis in the mouse kidney was done by using antibody against synthesized oligopeptide of mOCTL1. The immunohistochemical result showed that mOCTL1 was stained at the glomerulus (the parietal epithelial cells and podocytes), pars recta of proximal tubule, distal convoluted tubules, connecting tubules and collecting tubules. From these results, we conclude that mOCTL1 may be a candidate for an organic ion transporter isoform in the mouse kidney.
Amino Acid Sequence ; Animals ; Blotting, Western ; Gene Library ; Humans ; Immunohistochemistry ; Kidney/*metabolism ; Mice ; Molecular Sequence Data ; Organ Specificity ; Organic Cation Transport Proteins/genetics/*isolation & purification ; Organic Cation Transporter 1/genetics/*isolation & purification ; Protein Isoforms/isolation & purification

OBJECTIVETo evaluate the association between SLC22A1 expression and the outcomes of hepatocellular carcinoma (HCC) patients.

METHODSA tissue microarray of 303 HCC and matched adjacent noncancerous liver tissues (ANLTs) were constructed. The expression of SLC22A1 was tested by immunohistochemistry (IHC) and scored by two pathologists according to a 12-score scale (a score>6 was defined as high expression, and a score≤6 as low expression). The correlation of SLC22A1 expression with the clinicopathological features and the patients' outcome was analyzed.

RESULTSAll the ANLTs had a IHC score of 12, as compared to only 29 (9.6%) of the HCC tissues. The patients were divided into 2 groups based on the IHC scores: 59% (180/303) in low expression group and 41% (123/303) in high expression group. The disease-free survival (DFS) rates and overall survival (OS) rates were significantly lower in low SLC22A1 expression group than in the high expression group. The 1-, 3-, and 5-year DFS rates were 43%, 31% and 27% in the low expression group, and were 58%, 47% and 43% in the high expression group, respectively. The 1-, 3-, and 5-year OS rates were 66%, 38% and 32% in low expression group, and were 80%, 57% and 50% in the high expression group, respectively. A low expression of SLC22A1 was positively correlated with the tumor diameter, BCLC stage, tumor differentiation, and AFP levels (P<0.05), and was an independent predictor of poor overall survival (HR=1.454; 95% CI, 1.050-2.013).

CONCLUSIONSDown-regulation of SLC22A1 is a malignant feature and a potential prognostic marker of HCC.

Carcinoma, Hepatocellular ; diagnosis ; metabolism ; Disease-Free Survival ; Down-Regulation ; Humans ; Immunohistochemistry ; Liver Neoplasms ; diagnosis ; metabolism ; Organic Cation Transporter 1 ; metabolism ; Prognosis ; Survival Rate ; Tissue Array Analysis

OBJECTIVETo explore the correlation between hOCT1 polymorphism and imatinib mesylate (IM) effectiveness in chronic myelogenous leukemia(CML) patients, and to provide for the clinical individual personalized therapy.

METHODSFifty-three CML and 23 non-CML patients were enrolled in this study. Blood or bone marrow samples were collected. Amplification refractory mutation system (ARMS)-polymerase chain reaction was used to amplify the polymorphisms gene segment of hOCT1-P283L, R287G and M408V and their frequencies were statistically analysed. With clinical outcomes, the correlation between hOCT1 polymorphism and IM effectiveness in CML was analyzed.

RESULTS(1) For 74 Han Chinese, the allele frequencies of hOCT1-P283L, R287G and M408V were 39.86%, 29.05% and 45.27%, respectively. (2) The genotypes of hOCT1-P283L, R287G and M408V in 2 Tibetan Chinese were CC, CC, AG and CC, CG, AG, respectively. (3) In the CML patients with IM optimal response, the frequencies of 283T and 287G allele were predominant (P<0.05). No significant difference was found in the frequency distribution of hOCT1-M408V genotype and allele among the 3 different response groups (P>0.05).

CONCLUSION(1) Three single nucleotide polymorphisms (cSNP) P283L, R287G and M408V were found in the hOCT1 gene from 76 Chinese. (2) hOCT1 gene polymorphism is associated with the long-term molecular response of CML patients received IM therapy, indicating that the polymorphisms of hOCT1-283T, 287G may be good predictors for IM response. (3) There is no correlation between the polymorphisms of hOCT1-P283L, R287G, M408V and secondary IM resistance in CML patients.

Benzamides ; Female ; Gene Frequency ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; genetics ; Male ; Organic Cation Transporter 1 ; genetics ; Piperazines ; therapeutic use ; Polymorphism, Genetic ; Pyrimidines ; therapeutic use ; Treatment Outcome

Liver is regarded as one of the most important organs for drug clearance in the body, which mediates both the metabolism and biliary excretion of drugs. Transporters are a class of functional membrane proteins and control the movement of substances into or out of cells. Transporters, which are extensively expressed in the liver, play important roles in the drug hepatic disposition by regulating the uptake of drugs from blood into hepatocytes or the efflux of drugs and their metabolites into bile. In this review, the localization, functions and substrate selectivity of the major transporters in the liver will be summarized, and the impacts of these transporters on drug hepatic disposition, the potential drug-drug interactions as well as their genetic polymorphisms will also be reviewed.
ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Bile ; metabolism ; Biological Transport ; Drug Interactions ; Humans ; Liver ; metabolism ; Membrane Transport Proteins ; genetics ; metabolism ; Metabolic Clearance Rate ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; Neoplasm Proteins ; genetics ; metabolism ; Organic Anion Transporters ; genetics ; metabolism ; Organic Anion Transporters, Sodium-Dependent ; metabolism ; Organic Anion Transporters, Sodium-Independent ; genetics ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Pharmacokinetics ; Polymorphism, Genetic ; Symporters ; metabolism

The effects of mangiferin on uric acid excretion, kidney function and related renal transporters were investigated in hyperuricemic mice induced by potassium oxonate. Mice were divided into normal control group, and 5 hyperuricemic groups with model control, 50, 100, and 200 mg x kg(-1) mangiferin, and 5 mg x kg(-1) allopurinol. Mice were administered by gavage once daily with 250 mg x kg(-1) potassium oxonate for seven consecutive days to create the model. And 3 doses of mangiferin were orally initiated on the day 1 h after potassium oxonate was given, separately. Serum uric acid, creatinine and urea nitrogon levels, as well as urinary uric acid creatinine levels were measured. Mouse uromodulin (mUMOD) levels in serum, urine and kidney were determined by ELISA method. The mRNA and protein levels of related renal transporters were assayed by RT-PCR and Western blotting methods, respectively. Compared to model group, mangiferin significantly reduced serum uric acid, creatinine and urea nitrogon levels, increased 24 h uric acid and creatinine excretion, and fractional excretion of uric acid in hyperuricemic mice, exhibiting uric acid excretion enhancement and kidney function improvement. Mangiferin was found to down-regulate mRNA and protein levels of urate transporter 1 (mURAT1) and glucose transporter 9 (mGLUT9), as well as up-regulate organic anion transporter 1 (mOAT1) in the kidney of hyperuricemic mice. These findings suggested that mangiferin might enhance uric acid excretion and in turn reduce serum uric acid level through the decrease of uric acid reabsorption and the increase of uric acid secretion in hyperuricemic mice. Moreover, mangiferin remarkably up-regulated expression levels of renal organic cation and carnitine transporters (mOCT1, mOCT2, mOCTN1 and mOCTN2), increased urine mUMOD levels, as well as decreased serum and kidney mUMOD levels in hyperuricemic mice, which might be involved in mangiferin-mediated renal protective action.
Animals ; Blood Urea Nitrogen ; Carrier Proteins ; genetics ; metabolism ; Creatinine ; blood ; Glucose Transport Proteins, Facilitative ; genetics ; metabolism ; Hyperuricemia ; blood ; chemically induced ; physiopathology ; urine ; Kidney ; metabolism ; physiopathology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Octamer Transcription Factor-1 ; genetics ; metabolism ; Organic Anion Transport Protein 1 ; genetics ; metabolism ; Organic Anion Transporters ; genetics ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Organic Cation Transporter 2 ; Oxonic Acid ; Protective Agents ; pharmacology ; RNA, Messenger ; metabolism ; Random Allocation ; Solute Carrier Family 22 Member 5 ; Uric Acid ; blood ; urine ; Uromodulin ; blood ; urine ; Xanthones ; pharmacology

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

OBJECTIVETo determine plasma imatinib concentration, intracellular imatinib concentration, and hOCT1 and ABCB1 mRNA expression in bone marrow cells of CML patients to further evaluate the potential usefulness of these measures as markers of imatinib efficacy and their clinical relationships.

METHODSEighty CML patients in chronic phase receiving imatinib were enrolled in this study, including 56 males and 24 females with a median age of 39.5 (6 - 76) years. Imatinib was administered at a median dose of 400 (200 - 800) mg/d orally per day with a median course of 24 (3 - 90) months. The intracellular imatinib concentrations in bone marrow cells of 28 patients were simultaneously determined. Real-time quantitative PCR with a taqman probe was used to assess hOCT1 and ABCB1 mRNA expression on bone marrow cells of 36 patients. Imatinib trough concentration was determined by high-performance liquid chromatography-tandem mass spectrometry with a detectability of 2 - 10 000 µg/L. Serum α1-acid glycoprotein (AGP) was measured by immune turbidimetry on a BNProspec protein analyzer (Dade Behring, USA). All patients were divided into MMR, CCyR, PCyR or drug-resistant groups according to response.

RESULTSPlasma imatinib trough concentration of 80 patients was (1274.1 ± 559.1) (109.0 - 3400.0) µg/L. The plasma imatinib trough concentration of 59 (73.8%) patients with a dose of 400 mg/d was (1252.0 ± 569.5) (109 - 3400) µg/L, including 37 (62.7%) patients with concentrations of more than 1000 µg/L and 9 (15.2%) patients more than 800 µg/L. Plasma imatinib trough concentration in the MMR group \[(1531.9 ± 634.1) µg/L\] was significant higher than in the PCyR \[(812.8 ± 480.3) µg/L\] or drug-resistant group \[(875.2 ± 243.1) µg/L\] (P < 0.05). Plasma imatinib trough concentration in the CCyR group \[(1288.4 ± 498.2) µg/L\] was significant higher than in the PCyR group (P = 0.027). There was no significant difference between CCyR and MMR groups with regard to plasma imatinib trough concentration (P = 0.136). The intracellular imatinib concentration in bone marrow cells in the CCyR group \[12.6 (2.4 - 90.4) µg/L\] was significantly higher than drug-resistant \[6.6 (2.6 - 111.0) µg/L\] or PCyR \[2.7 (2.4 - 4.7) µg/L\] groups (P = 0.013). The hOCT1 mRNA expression on bone marrow cells in the CCyR group \[25.9(0.7 - 123.9) × 10(-5)\] was significantly higher than in drug-resistant \[7.8 (2.5 - 33.5) × 10(-5)\] or PCyR \[4.2 (1.4 - 11.9) × 10(-5)\] groups (P = 0.036). The ABCB1 mRNA expression on bone marrow cells in drug-resistant group \[136.7 (15.0 - 1604.9) × 10(-5)\] was significantly higher than in CCyR \[129.1 (12.9 - 783.3) × 10(-5)\] or PCyR \[34.4 (2.2 -108.2) × 10(-5)\] groups (P = 0.013). Plasma imatinib trough concentration was positively correlated with AGP (r = 0.446, P = 0.000) or dose (r = 0.346, P = 0.002). There were no significant correlations between plasma imatinib trough concentration and height, weight or body surface area (P > 0.05). There were no significant differences among different courses with regard to plasma imatinib trough concentration (P > 0.05).

CONCLUSIONClinical responses in CML patients were correlated with plasma and intracellular imatinib trough concentrations. Imatinib concentration was regulated by AGP and the activities of hOCT1 and ABCB1.

ATP Binding Cassette Transporter, Sub-Family B ; ATP-Binding Cassette, Sub-Family B, Member 1 ; metabolism ; Adolescent ; Adult ; Aged ; Benzamides ; blood ; pharmacokinetics ; therapeutic use ; Bone Marrow Cells ; metabolism ; Child ; Female ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; blood ; drug therapy ; metabolism ; Male ; Middle Aged ; Organic Cation Transporter 1 ; metabolism ; Piperazines ; blood ; pharmacokinetics ; therapeutic use ; Plasma ; metabolism ; Pyrimidines ; blood ; pharmacokinetics ; therapeutic use ; Treatment Outcome ; Young Adult