Suppression of OCT2/MRP2 decreases kidney injury and enhances the chemosensitivity of co-administration of cisplatin and astragaloside IV / 药学学报

Kidney injury and decreased chemosensitivity of tumor cells are obstacles with cisplatin (CDDP) chemotherapy. Down-regulation of the organic cation transporter 2 (OCT2) and multidrug resistance-associated protein 2 (MRP2) is a key means to alleviate CDDP-induced kidney injury and increase chemosensitivity. Astragaloside IV (AS IV) is obtained from the well-known traditional Chinese herb Astragalus membranaceus. This study explored the role of AS IV in preventing kidney injury and enhancing the antitumor effect of CDDP by suppressing OCT2 expression in kidney and MRP2 in tumors. This project was reviewed and approved by the Animal Ethics Committee of the First Hospital of Jilin University. The effects of AS IV on CDDP inhibition of tumor growth and promotion of apoptosis were assessed in Lewis lung tumor (LLC)-bearing mice by H&E and TUNEL staining. Kidney injury was assessed by serum biochemical parameters and H&E staining. We used Western blotting and immunohistochemistry assays to detect OCT2 and MRP2 expression in kidney and tumor. The concentration of CDDP in kidney and tumor was measured by HPLC-MS/MS. AS IV enhanced CDDP chemosensitivity by increasing tumor cell apoptosis and slowing tumor growth, and decreased kidney injury as evidenced by lower blood creatinine (Cr) and blood urea nitrogen (BUN). Co-administration of AS IV suppressed MRP2 overexpression induced by CDDP in tumor tissues and may be an important mechanism for enhancing CDDP chemosensitivity. Moreover, AS IV reduced CDDP-induced kidney injury in mice along with suppression of OCT2 expression in kidney. The concentration of CDDP was increased in tumor but decreased in kidney. In total, AS IV not only enhanced the antitumor effect of CDDP by suppressing MRP2 expression in tumor cells, but also decreased kidney injury induced by CDDP. The results provide new insight into the combined use of a chemotherapy drug and natural ingredients to treat cancer.

Kaempferol in reversing drug resistance of chronic myelogenous leukemia K562/ADM cells and its related mechanism / 白血病·淋巴瘤

Objective@#To investigate the drug resistance of kaempferol reversed adriamycin (ADM)-resistant K562/ADM cells in chronic myelogenous leukemia (CML) and its related mechanism.@*Methods@#Methyl thiazolyl tetrazolium (MTT) method was used to detect the toxicity of ADM on K562 and K562/ADM cells for 24 h. The half inhibitory concentration (IC50) of ADM and the drug resistance multiple for 24 h were calculated. MTT method was used to detect the toxicity of kaempferol on K562/ADM cells for 24 h. The 5% inhibitory concentration (IC5) and 10% inhibitory concentration (IC10) of kaempferol for 24 h were calculated to determine the concentration of kaempferol in the subsequent experiments. And the cells untreated by the kaempferol were selected as the control group. The cell inhibition after the treatment of ADM for 24 h of the blank control group and kaempferol intervention group was detected by using MTT method. And then the cell inhibition for 24 h and ADM IC50 for 24 h in the above groups were calculated. The ratio of IC50 in the blank control group and kaempferol group was the reversal drug resistance multiple of kaempferol. The fluorescence intensity of ADM in K562/ADM cells treated by kaempferol was detected by using flow cytometry. Western blotting was used to detect the expressions of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), phosphorylated p38 (p-p38), and total p38 (t-p38) protein in K562/ADM cells after the treatment of kaempferol, the specific inhibitor of p38-MAPK signaling pathway SB202190, and the combination of kaempferol and SB202190.@*Results@#After the treatment of ADM for 24 h, the IC50 value of K562 and K562/ADM cells was (0.9±0.6), (28.1 ±3.5) μg/ml, respectively. The drug resistance multiple of K562/ADM cells on the treatment of ADM for 24 h was 31.16 compared with the K562 cells. MTT method showed that kaempferol inhibited the proliferation of K562/ADM cells in a dose-dependent manner. According to the IC5 and IC10, 0.5 μmol/L and 1.0 μmol/L kaempferol were determined to do the subsequent experiments. After the combined interaction of kaempferol and ADM for 24 h, the ADM IC50 of K562/ADM cells in the blank control group, 0.5 μmol/L kaempferol group and 1.0 μmol/L kaempferol group was (33.7±5.7), (21.4±0.6), (15.9±1.8) μg/ml, respectively (F = 30.85, P < 0.05), and there was a statistical difference of pairwise comparison (both P < 0.05). The reversal drug resistance multiple of K562/ADM cells for 24 h in 0.5 μmol/L kaempferol group and 1.0 μmol/L kaempferol group was 1.58 and 2.12, respectively. Flow cytometry results showed that the mean fluorescence intensity (MFI) of ADM in the blank control group, 0.5 μmol/L kaempferol group and 1.0 μmol/L kaempferol group was 138.4±8.9, 154.3±2.2, 165.7±4.8, respectively, and the difference was statistically significant (F = 161.48, P < 0.05). Compared with the blank control group, after treatment of K562/ADM cells with 0.5 μmol/L and 1.0 μmol/L kaempferol for 24 h, the relative expressions of P-gp, MRP1 and p-p38 protein were decreased in K562/ADM cells (all P < 0.05), but there was no statistical difference in the expression of t-p38 protein (P > 0.05); SB202190 could reduce the relative expressions of P-gp, MRP1 and p-p38 protein (all P < 0.05); after the treatment of SB202190 combined with different concentration of kaempferol, the relative expressions of P-gp, MRP1 and p-p38 protein in K562/ADM cells did not decrease (P > 0.05).@*Conclusions@#Kaempferol can decrease the relative expressions of P-gp and MRP1 in K562/ADM cells by inhibiting p38-MAPK pathway, so as to increase the concentrations of ADM and to reverse the drug resistance of K562/ADM cells.

Research on Therapeutic Mechanism of Canhuang Tablets on Jaundiced Rats Induced by ANIT / 中国实验方剂学杂志

Objective:To explore the therapeutic mechanism of Canhuang tablets on the mRNA and protein expression of farnesoid X receptor (FXR), uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and multidrug resistance associated protein 2 (MRP2) in the liver of jaundiced rats induced by α-naphthalene isothiocyanate (ANIT). Method:The rats were divided into normal group, model group, Canhuang tablets (CHP) group and ursodeoxycholic acid tablets (UDCA) group. The jaundice model was reproduced by ANIT. After the intervention of the corresponding drugs, the contents of total bilirubin (TBIL), total bile acid (TBA), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and the liver histopathology were examined to evaluate the therapeutic effect of CHP. The relative mRNA and protein expressions of FXR, UGT1A1 and MRP2 in rat liver tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Result:CHP can significantly reduce the increase of TBIL, TBA, ALT, AST and ALP caused by ANIT in rat serum, and inhibit the liver pathological changes, which showed that the removing jaundice effect of CHP was better than UDCA. Compared with the normal group, ANIT significantly inhibited the mRNA levels of FXR, UGT1A1 and MRP2 in rat liver tissues after modeling (P<0.01). Compared with the model group, CHP and UDCA significantly increased the mRNA levels of target genes of each protein after intervention (P<0.01), and CHP was superior to UDCA in improving the mRNA level of bilirubin metabolizing enzyme UGT1A1 (P<0.01). In the aspect of affecting protein expression, compared with the normal group, ANIT modeling significantly increased the expression of FXR in rats (P<0.05). CHP intervention showed a tendency to promote the expression of FXR, while UDCA did not, but there was no significant difference between them. In the aspects of promoting bilirubin metabolism and bile excretion, the expressions of UGT1A1 and MRP2 were significantly decreased by ANIT modeling (P<0.01), while the expressions of UGT1A1 and MRP2 proteins were significantly increased after treatment of CHP (P<0.01). CHP was superior to UDCA in increasing the expression of bilirubin and bile acid efflux protein MRP2 (P<0.01). Conclusion:The jaundice abating mechanism of CHP is related to activating FXR mRNA expression in liver, promoting the mRNA and protein expression of bilirubin metabolizing enzyme UGT1A1 and bile acid transporter MRP2, improving liver metabolism of free bilirubin and promoting bile acid excretion from the liver, and alleviating cholestatic liver injury.

TNFα Induces Multidrug Resistance-Associated Protein 4 Expression through p38-E2F1-Nrf2 Signaling in Obstructive Cholestasis

PURPOSE: To explore the molecular mechanism of the upregulation of multidrug resistance-associated protein 4 (MRP4) in cholestasis. MATERIALS AND METHODS: The mRNA and protein levels of MRP4 in liver samples from cholestatic patients were determined by quantitative real-time PCR and Western blot. In human hepatoma HepG2 cells, electrophoretic mobility shift assay (EMSA) was used to determine the affinity of nuclear factor-E2-related factor (Nrf2) binding to MRP4 promoter. Dual-luciferase reporter assay was used to detect the binding of tumor necrosis factor α (TNFα) to the promotor of E2F1. The bile duct ligation mouse models were established using male C57BL/6 mice. RESULTS: The mRNA and protein levels of MRP4 were significantly increased in cholestatic patients. TNFα treatment induced the expression of MRP4 and Nrf2 and enhanced cell nuclear extract binding activity to MRP4 promoter, as demonstrated by EMSA. Nrf2 knockdown reduced MRP4 mRNA levels in both HepG2 and Hep-3B cells. In addition, TNFα increased Rb phosphorylation and expression of MRP4 and Nrf2 and activated E2F1 and phosphorylated p38 in HepG2 and Hep-3B cells. These effects were markedly inhibited by pretreatment with E2F1 siRNA. Dual-luciferase reporter assay validated that TNFα induces the transcription of E2F1. Furthermore, the expression of MRP4, Nrf2, E2F1, and p-p38 proteins was improved with treatment of TNFα in a mouse model of cholestasis. E2F1 siRNA lentivirus or SB 203580 (p38 inhibitor) inhibited these positive effects. CONCLUSION: Our findings indicated that TNFα induces hepatic MRP4 expression through activation of the p38-E2F1-Nrf2 signaling pathway in human obstructive cholestasis.

Mrp1 is up-regulated in lung tissues of mildly stable COPD mice induced by smoke, Nrf2 pathway may be involved / 中国药理学通报

Aim: To investigate the effect of Nrf2 pathway on the expression of MRP1 in mildly stable COPD mice. Methods: The mild COPD mouse model was established by passive cigarette smoking. The pathological changes of lung tissues were examined by HE staining. Immunohistochemistry and Western blot were used to detect the protein expression of MRP1, Nrf2 and HO-1. Results: Compared with normal group, each lung function index of the mild-moderate COPD model group was significantly lower, but compared with wide type(WT) model group, the reduction was more significant in Nrf2-/- model group. HE results showed diffuse inflammatory reaction and alveolar bronchial structure damage in alveolar of WT and Nrf2-/- model mice, and it was more pronounced in Nrf2-/- mice. Immunohistochemistry and Western blot results showed that the expression of MRP1 in lung tissue of Nrf2-/- normal mice was significantly reduced compared with the normal WT group. After passive cigarette smoking, The expression of MRP1, Nrf2 and HO-1 in WT model group increased significantly, but compared with Nrf2-/- normal mice, there was no significant change in the expression of MRP1 in Nrf2-/- model group. Conclusions: Mildly stable COPD mice may counteract the xenobiotic damage caused by cigarette smoke through up-regulating the expression of MRP1 protein, which may be associated with Nrf2 signaling activation.

Alteration of MRP2 expression and the graft outcome after liver transplantation

PURPOSE: Multidrug resistance-associated protein (MRP) 2 is a glutathione conjugate in the canalicular membrane of hepatocytes. Early graft damage after liver transplantation (LT) can result in alteration of MRP2 expression. The purpose of this study was to evaluate the relationship between the pattern of MRP2 alteration and graft outcome. METHODS: Forty-one paraffin-embedded liver graft tissues obtained by protocol biopsy within 2 months after LT; these were stained using monoclonal antibodies of MRP2. We selected 15 live donor biopsy samples as a control, that showed homogenous canalicular staining for MRP2. The pattern of canalicular MRP2 staining of graft was classified into 3 types: homogenous (type C0), focal (type C1), and no (type C2,) staining of the canaliculi. RESULTS: In total, 17.1% graft tissues were type C0, 36.6% were type C1, and 46.3% were type C2. The median operation time was longer in patients with type C2 (562.6 minutes) than in patients with type C0 (393.8 minutes) (P = 0.038). The rates of posttransplant complications were higher in patients with type C2 (100%) than in patients with type C0 (42.9%) and C1 (73.3%) (P < 0.001). CONCLUSION: MRP2 expression pattern was altered in 82.9% after LT. The pattern of MRP2 alteration was associated with longer operation time and higher rates of post-LT complications.

Effects of Glycyrrhiza uralensis Extract on the Expression of UGT1A and MRP2 in Human Liver L-02 Cells Damaged by Triptolide / 中国药房

OBJECTIVE:To investigate the effects of Glycyrrhiza uralensis extract (GE) on the expression of uridine diphosphate glucuronyltransferase 1A (UGT1A) and multidrug resistance associated protein 2 (MRP2) in human liver L-02 cells damaged by triptolide (TP),and to study attenuated mechanism of G.uralensison for TP.METHODS:The survival rates of L-02 cells were determined by MTT assay after cultured with 0 (blank control),40,80,160 nmol/L TP for 12,18,24 h.L-02 cells were divided into blank control group (blank culture medium),model control group (80 nmol/L TP) and GE pretreatment group (adding 80 nmol/ L TP after pretreated with 30,60,90 mg/L GE for 24 h);after cultured for 18 h,survival rates of L-02 cells were determined by MTT assay.Rifampin (RIF) group (positive control,adding 80 nmoi/L TP after pretreated with 10 μmol/L RIF for 24 h) was added on the basis of the above grouping (GE concentration of 60 mg/L in GE pretreatment group).After cultured for 24 h,the protein expressions of UGT1A and MRP2 were detected.RESULTS:The inhibition effect of TP on cell proliferation was positively correlated with the concentration and the time.Compared with blank control group,cell survival rate of model control group was decreased significantly (P＜0.05),and the protein expression of MRP2 was decreased significantly (P＜0.01).Compared with model control group,cell survival rates of 30,60,90 mg/L GE pretreatment groups were all increased significantly (P＜0.01).The protein expressions of UGT1A and MRP2 were increased significantly in 60 mg/L GE pretreatment group (P＜0.01).CONCLUSIONS:GE pretreatment can relieve TP-induced human liver L-02 cell damage,and its attenuated mechanism may be associated with the increase the expression of UGT1A and MRP2.

Metabolism and Transport of 7，4'-dihydroxyflavone in Caco-2 Cell Model / 医药导报

Objective To study the effects of different transport protein on the transport of 7,4'-dihydroxyflavone (7,4'-DHF) and its metabolite (7,4'-DHF-S) in Caco-2 cell model.Methods Ultra performance liquid chromatography was employed to determinethe content of 7,4'-DHF and 7,4'-DHF-S incubation buffer,their structures were identified by LC-MS/MS.Bidirectional transport of Caco-2 cells model was used to investigate the influence of ko143 (the inhibitor of BCRP) and MK571 (the inhibitor of MRP2) on the transport of 7,4'-DHF and 7,4'-DHF-S,respectively.Results Metabolic product of 7,4'-DHF in Caco-2 monolayer cell was identified as one monosulfate;PDR of 7,4'-DHF was (1.43 ± 0.11),PDR of ko143 and MK571 on the apparent permeability of 7,4'-DHF was (1.59 ± 0.04) and (1.48 ± 0.07) (P ＞ 0.05);PDR of 7,4'-DHF-S was (1.60 ± 0.06);ko143 could significantly reduce the apparent permeability of 7,4'-DHF-S,and the PDR was (0.23 ±0.03) (P ＜ 0.01);MK571 had no significant effect on the apparent permeability of the 7,4'-DHF-S,and the PDR was (1.51±0.04) (P ＞ 0.05).Conclusion Caco-2 cells can mediate the suffonated reaction of 7,4'-DHF;7,4'-dihydroxyflavone sulfonated combination product may be a substrate for BCRP.

Establishment of double-transfected MDCK Ⅱ cells expressing human organic anion transporting polypeptide 1B1 and multidrug resistance-associated protein 2 and identification of its functions / 复旦学报（医学版）

Objective To establish double-transfected Madin-Darby canine kidney (MDCK) [Ⅱ cells expressing human organic anion transporting polypeptide 1B1 (hOATP1B1) and multidrug resistanceassociated protein 2 (hMRP2)and to testify their functions,moreover,to study the transcellur transport of indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyltryptophan (1-MT) in the transfectants.Methods hOATP1B1/hMRP2 eukaryotic vectors pVITRO2-SLCO1B1-ABCC2 was obtained by genetic engineering method and then transfected into MDCK cells.Stably expressed MDCK cells were screened by using the geneticin G418.Real-time PCR,Western blot analysis and immuno fluorescent confocal microscopy were used to verify the proteins expression.Transport of the representative substrate pravastatin in different pH values and substrate concentrations and 1-MT were evaluated using the double transfectants.Results MDCK-OATP1B1/MRP2 was successfully established.Pravastatin displayed the optimal transcellular transport when pH value was 6.5.Transport of pravastatin demonstrated the concentration-dependent in the concertation range of 0) to 500 μmol/L.Transport of 1-MT showed no significant difference in MDCK cells and transfectants.Conclusions MDCK-OATP1B1/MRP2 was successful established;1-MT was not the substrate of OATP1B1 or MRP2 protein;and the eatablished double transfectant cell lines can be used to evaluate OATP1B1/MRP2-medicated transport of xenobiotics (e.g.new drug candidates) and endogenous compounds (e.g.bilirubin).

Relationship between pokemon gene expression and drug resistance of gastric carcinoma / 第二军医大学学报

Objective To explore the relationship of pokemon gene expression and drug sensitivity and drug resistance gene in gastric cancer cells. Methods We collected the paraffin specimen of gastric cancer and para-carcinoma tissues from 60 patients with gastric cancer, detected the protein expressions of pokemon, drug resistance-associated protein P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), lung resistance protein (LRP) and survivin with immunohistochemistry (IHC) and analyzed the relationship between pokemon protein and other 4 proteins. Sulphorhodamine B (SRB) protein staining assay was performed to detect the inhibition effect of 5-fluorouracil (5-FU), cisplatin (DDP) and oxaliplatin (L-OHP) on gastric cancer cell line SGC7901, multidrug-resistant gastric carcinoma cell line SGC7901/ADR and gastric epithelial cell line GES-1, and qPCR and Western blotting were used to test expression of pokemon and drug resistance genes in the cells. Pokemon-siRNA was established and transfected into SGC7901/ADR cells, and the drug sensitivity and drug resistance genes were analyzed. Results Positive rates of pokemon, P-gp, MRP1, LRP and survivin proteins were significantly higher in gastric cancer tissues than those in para-carcinoma tissues (P<0.05). The protein expression of pokemon was positively correlated with P-gp and survivin (r=0.385 2, P=0.002; r=0.342 4, P=0.007). Protein expressions of pokemon, P-gp, MRP1, and survivin were higher in SGC7901/ADR cells than those in SGC7901 and GES-1 cells. The drug resistance of SGC7901/ADR cells was the strongest, followed by SGC7901, and that of GES-1 was the weakest (P<0.01). After SGC7901/ADR cells was transfected with pokemon-siRNA, pokemon mRNA expression was significantly inhibited, mRNA and protein expressions of P-gp and survivin were decreased and the inhibitory effect of chemotherapy agents on SGC7901/ADR cells was increased (P<0.05). Conclusion The pokemon is involved in drug resistance of gastric cancer by mutual regulation with P-gp and survivin, and pokemon may be a candidate gene for gastric cancer targeted treatment.

Effects of MRP4 gene on lipopolysaccharide-induced endothelial permeability and the cytoskeleton of endothelial cells changes / 中华急诊医学杂志

Objective To investigate the effects of multidrug resistance-associated protein 4 (MRP4) on the cytoskeleton and cellular permeability of rat pulmonary microvascular endothelial cells (PMVECs) induced by lipopolysaccharide (LPS).Methods PMVECs were cultured for 3 to 6 generations were randomly divided into 4 groups:control group,LPS group,Ad-shMRP4 group (adenoviral expression of a short-hairpin RNA directed against MRP4),Ad-shRNA group.The infection rate of cells was detected by fluorescence microscope observation.The level of MRP4 was assayed by Western botting.Monolayer permeability was determined by the Transwell assay.The morphological characteristic and distribution of Factin was measured by laser confocal fluorescence microscope.Results Compared with control group,the expression of MRP4 protein was up-regulated (P ＜ 0.05) and the significant increase in the permeability of endothelial cells (2 h,6 h,12 h and 24 h respectively:0.28 ±0.02 vs.0.41 ±0.04,0.32 ±0.02,0.30 ±0.01 vs.0.53±0.04,0.39±0.03,0.33 ±0.04 vs.1.12±0.17,0.70 ±0.07,0.32±0.03 vs.0.79 ± 0.02,0.57 ± 0.05,P ＜ 0.05),the F-actin was remodeled,and the stress fibers were formed in LPS group and Ad-shMRP4 group.However,compared with LPS group,the expression of MRP4 protein was down-regulated (P ＜ 0.05) and the markedly decrease in the permeability of endothelial ceils (2 h,6 h,12 h and 24 h respectively:0.41 ± 0.04 vs.0.32 ± 0.02,0.53 ± 0.04 vs.0.39 ± 0.03,1.12 ± 0.17 vs.0.70 ± 0.07,0.79 ± 0.02 vs.0.57 ± 0.05,P ＜ 0.05) was found,and the remodeling of F-actin,and the formation of stress fibers were observed in Ad-shMRP4 group.Conclusions Silencing of MRP4 gene can effectively attenuates LPS-induced increase in the endothelial cell permeability and the destruction of cytoskeleton,thus playing an important role in the protection of endothelial cell barrier.

Effects of MRP4 gene on lipopolysaccharide-induced endothelial permeability and the cytoskeleton of endothelial cells changes / 中华急诊医学杂志

Objective To investigate the effects of multidrug resistance-associated protein 4 (MRP4) on the cytoskeleton and cellular permeability of rat pulmonary microvascular endothelial cells (PMVECs) induced by lipopolysaccharide (LPS).Methods PMVECs were cultured for 3 to 6 generations were randomly divided into 4 groups:control group,LPS group,Ad-shMRP4 group (adenoviral expression of a short-hairpin RNA directed against MRP4),Ad-shRNA group.The infection rate of cells was detected by fluorescence microscope observation.The level of MRP4 was assayed by Western botting.Monolayer permeability was determined by the Transwell assay.The morphological characteristic and distribution of Factin was measured by laser confocal fluorescence microscope.Results Compared with control group,the expression of MRP4 protein was up-regulated (P ＜ 0.05) and the significant increase in the permeability of endothelial cells (2 h,6 h,12 h and 24 h respectively:0.28 ±0.02 vs.0.41 ±0.04,0.32 ±0.02,0.30 ±0.01 vs.0.53±0.04,0.39±0.03,0.33 ±0.04 vs.1.12±0.17,0.70 ±0.07,0.32±0.03 vs.0.79 ± 0.02,0.57 ± 0.05,P ＜ 0.05),the F-actin was remodeled,and the stress fibers were formed in LPS group and Ad-shMRP4 group.However,compared with LPS group,the expression of MRP4 protein was down-regulated (P ＜ 0.05) and the markedly decrease in the permeability of endothelial ceils (2 h,6 h,12 h and 24 h respectively:0.41 ± 0.04 vs.0.32 ± 0.02,0.53 ± 0.04 vs.0.39 ± 0.03,1.12 ± 0.17 vs.0.70 ± 0.07,0.79 ± 0.02 vs.0.57 ± 0.05,P ＜ 0.05) was found,and the remodeling of F-actin,and the formation of stress fibers were observed in Ad-shMRP4 group.Conclusions Silencing of MRP4 gene can effectively attenuates LPS-induced increase in the endothelial cell permeability and the destruction of cytoskeleton,thus playing an important role in the protection of endothelial cell barrier.

Relationship between pokemon gene expression and drug resistance of gastric carcinoma / 第二军医大学学报

Objective To explore the relationship of pokemon gene expression and drug sensitivity and drug resistance gene in gastric cancer cells.Methods We collected the paraffin specimen of gastric cancer and para-carcinoma tissues from 60 patients with gastric cancer,detected the protein expressions of pokemon,drug resistance-associated protein P-glycoprotein (P-gp),multidrug resistance-associated protein 1 (MRP1),lung resistance protein (LRP) and survivin with immunohistochemistry (IHC) and analyzed the relationship between pokemon protein and other 4 proteins.Sulphorhodamine B (SRB) protein staining assay was performed to detect the inhibition effect of 5-fluorouracil (5-FU),cisplatin (DDP) and oxaliplatin (L-OHP) on gastric cancer cell line SGC7901,multidrug-resistant gastric carcinoma cell line SGC7901/ADR and gastric epithelial cell line GES-1,and qPCR and Western blotting were used to test expression of pokemon and drug resistance genes in the cells.Pokemon-siRNA was established and transfected into SGC7901/ADR cells,and the drug sensitivity and drug resistance genes were analyzed.Results Positive rates of pokemon,P-gp,MRP1,LRP and survivin proteins were significantly higher in gastric cancer tissues than those in para-carcinoma tissues (P＜0.05).The protein expression of pokemon was positively correlated with P-gp and survivin (r=0.385 2,P=0.002;r=0.342 4,P=0.007).Protein expressions of pokemon,P-gp,MRP1,and survivin were higher in SGC27901/ ADR cells than those in SGC7901 and GES-1 cells.The drug resistance of SGC7901/ADR cells was the strongest,followed by SGC7901,and that of GES-1 was the weakest (P＜0.01).After SGC7901/ADR cells was transfected with pokemonsiRNA,pokemon mRNA expression was significantly inhibited,mRNA and protein expressions of P-gp and survivin were decreased and the inhibitory effect of chemotherapy agents on SGC7901/ADR cells was increased (P＜0.05).Conclusion The pokemon is involved in drug resistance of gastric cancer by mutual regulation with P-gp and survivin,and pokemon may be a candidate gene for gastric cancer targeted treatment.

Advances in the research of pharmacogenomics of tamoxifen / 药学学报

Tamoxifen (TAM) is the most common nonsteroidal antiestrogen agent, which has been widely used in the prevention of recurrence of estrogen or progesterone receptor-positive breast cancer in patients. It is metabolized by cytochrome P450 oxidases to its active metabolite (4-hydroxytamoxifen, 4-OH-TAM) and endoxifen (EDF), which played a critical role in the therapy. 4-OH-TAM and EDF have 30-to 100-fold more potency than TAM in the suppression of estrogen-dependent breast cancer cell proliferation. CYP3A4 and CYP2D6, as the key drug-metabolizing enzymes in those metabolic actions, are known to have several alleles. Genetic polymorphisms of CYP2D6 and CYP3A4 will influence the plasma concentrations of active TAM metabolites and clinical outcomes for breast cancer patients treated with TAM. The genetic polymorphisms of drug transporters, involved in the disposition of active TAM metabolites, also have the potential to influence the plasma concentrations of active TAM metabolites and clinical outcome for the treatment of breast cancer. In this review, we summarized the association of the genetic polymorphisms in the metabolic enzymes and transporters involved in the metabolism and disposition of TAM with the metabolite concentration, efficacy and adverse effects of TAM, which provides a fundamental reference for further pharmacogenomic study and clinical use of TAM.

Protective effect of multidrug resistant associated protein 4 inhibitor on rats with sepsis-induced acute lung ;injury / 中华危重病急救医学

Objective To investigate the protective effect of multidrug resistant associated protein 4 (MRP4) inhibitor on rats with sepsis-induced acute lung injury (ALI). Methods Sixty Sprague-Dawley (SD) rats were randomly divided into sham group, sepsis group and MRP4 inhibitor MK571 treatment group, with 20 rats in each group. Sepsis model was reproduced by cecal ligation and puncture operation (CLP), and the rats in sham group were only received celiotomy without ligation and puncture. Rats in MK571 treatment group were intraperitoneally injected with MRP4 inhibitor MK571 (20 mg/kg) 30 minutes before model reproduction, while rates in sham group and sepsis group were given the same amount of normal saline. Twenty-four hours later, the femoral artery blood of mice was collected, and arterial blood gas analysis was measured. Serum tumor necrosis-α (TNF-α) was determined by enzyme-linked immunosorbent assay (ELISA). The lung tissues were collected, and the wet/dry weight ratio (W/D) was calculated. The expression of MRP4 protein in lung tissue was determined by Western Blot. Results Compared with sham group, arterial blood pH value and arterial partial pressure of oxygen (PaO2) were significantly lowered [pH value: 7.18±0.03 vs. 7.40±0.03; PaO2 (mmHg, 1 mmHg = 0.133 kPa): 63.15±6.24 vs. 98.05±2.58], while arterial partial pressure of carbon dioxide (PaCO2) was dramatically higher in the sepsis group (mmHg: 56.60±8.30 vs. 37.85±3.18), serum TNF-α level in the sepsis group was significantly increased (ng/L: 146.24±19.99 vs. 25.77±9.83), the W/D ratio of lung tissue was significantly increased (7.75±0.47 vs. 4.09±0.58), and the expression of MRP4 protein was up-regulated in the sepsis group (gray value: 0.153±0.006 vs. 0.087±0.005, all P < 0.05). Compared with the sepsis group, arterial blood pH value (7.30±0.02 vs. 7.18±0.03) and PaO2 (mmHg: 80.30±5.34 vs. 63.15±6.24) were significantly elevated in the MK571 treatment group, while PaCO2 was dramatically decreased (mmHg: 29.25±3.24 vs. 56.60±8.30), the serum level of TNF-α was significantly decreased (ng/L: 97.96±16.72 vs. 146.24±19.99), the W/D ratio of lung tissue was significantly reduced (5.89±0.51 vs. 7.75±0.47), and MRP4 protein expression was significantly down-regulated (gray value: 0.124±0.006 vs. 0.153±0.006, all P < 0.05). Conclusion MRP4 inhibitor may improve lung function in rats with sepsis-induced ALI by down-regulating MRP4 protein expression and reducing levels of inflammatory cytokines, which exerts protective effect on ALI.

Inhibition of multidrug resistance-associated protein 4 protects against pulmonary vascular endothelial barrier dysfunction in septic rats / 中华急诊医学杂志

Objective To explore the effects of multidrug resistance-associated protein 4 (MRP4) inhibition on pulmonary vascular endothelial barrier dysfunction in septic rats.Methods Sixty Sprague Dawley rats were randomly (random number) divided into three groups:sham-operated group,sepsis group,and sepsis plus MRP4 inhibitor treatment group,with 20 rats in each group.Sepsis was induced by cecal ligation and puncture.MRP4 inhibitor MK571 (20 mg/kg) was administrated by intraperitoneal injection 30 minutes before induction of sepsis.Twenty-four later,serum interlukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels were measured by enzyme-linked immunosorbent assay.Lung injury was assessed by histopathological examination.Lung vascular permeability was evaluated by quantitation of Evans blue dye extravasation from vascular space to lung parenchyma.Results Compared with sham group,serum IL-6 and TNF-α levels were significantly higher in sepsis group.In addition,lung injury and lung vascular permeability were elevated in sepsis group compared to sham group.Importantly,MRP4 inhibitor treatment significantly decreased serum IL-6 and TNF-α levels,improved lung injury and reduced lung vascular permeability in septic rats.Conclusions Inhibition of MRP4 protects against pulmonary vascular endothelial barrier dysfunction in septic rats.

Levels of miR-133 a/b and MRP1 in peripheral blood of patients with drug-refractory epilepsy / 中国病理生理杂志

AIM:To investigate the levels and clinical significance of microRNA-133a/b (miR-133a/b) and multidrug resistance-associated protein 1 ( MRP1 ) in peripheral blood of the patients with drug-refractory epilepsy. METHODS:Prediction of the miRNAs targeting transcriptional regulation of MRP1 was conducted by bioinformatics analy-sis.The plasmids containing wild type and mutant 3’UTR of MRP1 reporter gene were constructed.Dual luciferase report-er gene assay was used to verify this prediction.In addition, the peripheral blood samples of the epilepsy patients (37 cases were drug-refractory, the other 58 cases were nonresistant) were collected.The levels of miR-133a/b and MRP1 were measured by real-time PCR and ELISA.RESULTS:Through TargetScan database, it was predicted that miR-133a/b tran-scriptionally regulated MRP1.The results of dual luciferase report gene assay suggested that luciferase activity in experi-mental group with miR-133a/b mimics, pMIR-MRP1 and pRLTK plasmids were down-regulated by 76.9% and 64.1%compared with that in control group with scramble mimic, pMIR-MRP1 and pRLTK plasmids.The luciferase activity was up-regulated by 3.62 times and 2.04 times in mutation group with miR-133a/b mimics, pMIR-mut-MRP1 and pRLTK plasmids compared with experimental group.Before administration, the serum levels of miR-133a/b in the epilepsy patients without drug resistance was 2.18 times and 1.74 times higher than than in the epilepsy patients with drug resistance ( P<0.05), respectively, while MRP1 expression level was 3.72 times higher in the epilepsy patients with drug resistance than those in the epilepsy patients without drug resistance.After administration, the levels of miR-133a/b in the epilepsy pa-tients without drug resistance were 2.76 times and 2.95 times higher than those in the epilepsy patients with drug resistance (P<0.05), respectively, while the serum level of MRP1 in the epilepsy patients with drug resistance was 4.99 times higher than that in the epileptic patients without drug resistance (P<0.01).CONCLUSION:miR-133a/b transcriptio-nally regulates MRP1.There are lower expression levels of miR-133a/b and higher expression level of MRP1 in the epilep-sy patients with drug resistance compared with those in the epilepsy patients without drug resistance.miR-133a/b and MRP1 may be a diagnostic indicator for determining refractory epilepsy.

Clinical study of MRP and LRP mRNA expression in peple with human non-small cell lung cancer after cisplatin chemotherapy / 中国生化药物杂志

Objective To investigate the mRNA expression of the multidrug resistance associated protein and lung resistance protein in human non-small cell lung cancer tissues and their relationship with cis-platinum. Methods 13 samples were collected from patients with non small cell lung cancer before and after chemotherapy, the mRNA expression of MRP and LRP were detected using RT-PCR method, correlation between two genes were studied by Logistic regression analysis. Results Compared with before cisplatin chemotherapy, MRP and LRP expression of patients were increased after chemotherapy(P<0.05).Logistic regression analysis showed that there is no correlation between the two genes(r=0.036,P<0.05). Conclusion Cisplatin chemotherapy can increase the mRNA expression of MRP and LRP, and there is no correlation between the two genes.

The MRP1 expression in childhood acute lymphoblastic leukemia and its clinical significance / 临床儿科杂志

Objective Multidrug resistance-associated protein 1 (MRP1) has been reported with a close correlation with tumor multi-drug resistance. Real-time quantitative PCR (QRT-PCR) was performed to detect the MRP1 gene expression in childhood acute lymphoblastic leukemia (ALL) and its clinical signiifcance was analyzed. Methods Sixty-seven denovo ALL patients and 10 healthier children as bone marrow donor were studied. The chemotherapy was given according to CCLG-2008 protocol. SPSS software was employed to analyze the data and p-value below 0.05 was regarded as statistic signiifcance. Results MRP1 expression level showed a close correlation with ALL risk, the median of MRP1 expression was 4.28 (2.75~6.12), 5.62 (4.99~8.60) and 7.56 (3.66~11.13) for standard-risk group (SR), intermediate-risk group (IR) and high-risk group (HR), respectively. MRP1 mRNA expression in T-ALL group was 7.71 (6.49~14.35), which is higher than that of B-ALL (5.18(3.89~8.46)) (P<0.01). The rate of leukemia cells’ sensitivity to prednisone on 7th day was 70.6%in high expression group (n=34), which was signiifcantly lower than that in low expression group (n=33, 90.9%, P=0.035). The complete remission rateon 33th day was 64.7%in high expression group, and 87.9%in low expression group, which showed a signiifcant difference between them (P=0.026). Conclusions In children ALL, the expression of MRP1 is closely related with immunophenotyping, treatment response, hazard level and disease relapse.

MRP1 expression and bronchial epithelial function in lipopolysaccharide-induced rat model of chronic obstructive pulmonary disease / 中国实验动物学报

Objective To study the impact of establishment of lipopolysaccharide ( LPS )-induced rat model of chronic obstructive pulmonary disease (COPD)on the function of multidrug resistance-associated protein 1(MRP1)in the rat bronchial epithelium .Methods Using intratracheal instillation of LPS to establish COPD rat model .8-week old healthy male Wistar rats were divided into 3 groups (10 rats in each group ):(1) Normal control;(2) Modeling for 14 days after LPS instillation;(3) Modeling for 28 days after LPS instillation.Pulmonary function and the concentration of phenol red in bronchoalveolar lavage fluid ( BALF) and plasma were measured .The ratio of phenol red concentration in BALF/plasma was used as an index of the MRP 1 function in the rat bronchial epithelium and the expression of MRP 1 in the bronchial epi-thelium was also observed by immunohistochemistry .Results Compared with the normal group , the pulmonary functions of the rats in the model groups were significantly reduced along with the modeling progress .After intravenous administration of phenol red, the ratio of phenol red concentration in BALF/plasma was gradually reduced , and the expression of MRP1 in the bronchial epithelium was significantly decreased .Conclusions COPD rat model can be established by intratracheal LPS instillation, and the function of MRP1 in bronchial epithelium was gradually reduced along with the modeling progress .