Twist induces drug resistance in human lung cell line A549 by up-regulating MRP3 / 实用医学杂志

Objective To investigate the molecular mechanism of Twist induced-drug resistance in human lung cell line A549 cells.Methods The sensibility of A549 cells over-expressed Twist to cisplatin was measured by CCK8 assay. The expressions of Twist,MRP1,MRP2 and MRP3 were detected by RT-PCR. Western blotting was used to detect the expressions of Twist and MRP3 in A549 cells over-expressed Twist.The correlation between Twist and MRP3 expressions in 30 cases of lung cancer tissues was detected with immunohistochemistry. Results The viability of A549 cells over-expressed Twist was significant better than the control group under cispla-tin(32,64,128 μmol/L)treatment(0.79 ± 0.039,0.63 ± 0.048,0.46 ± 0.039 vs.0.53 ± 0.039,0.41 ± 0.043, 0.27 ± 0.063,respectively). After knockdown of MRP3 expression,it reversed drug resistance induced by Twist. Clinically,the expressions of Twist and MRP3 in lung cancer tissues were significantly relevant(P < 0.05). Conclusions Twist induces the drug resistance of human lung cell line A549 to cisplatin via up-regulating the expression of MRP3.

Influence of transcriptional factor Sp1 on expression of bile acids transporters MRP3 and MRP4 / 局解手术学杂志

Objective To investigate the influence of transcriptional factor Sp1 on expression of bile acids transporters MRP3 and MRP4 so as to perfect the regulatory mechanism of MRP3 and MRP4 expression.Methods Transformed Sp1-overexpression and Sp1 siRNA plas-mids to HepG2 cell and obtained the stably cells line.Then the expression levels of bile acids transporters MRP3 and MRP4 were measured by RT-qPCR,and the change of protein levels were detected by Western blot.Results The stably cells line Sp1-OE-HepG2 and Sp1siRNA-HepG2 were successfully transformed.The mRNA expression and protein levels of MRP3 and MRP4 were significantly increased in Sp1-OE-HepG2 cells,among which the mRNA expression of MRP3 mRNA increased 2.8 times,the protein levels of MRP3 increased 3.0 times,and the mRNA expression and protein levels of MRP4 increased 3.2 times and 2.5 times respectively.Conversely,the mRNA expression and protein levels of MRP3 and MRP4 were decreased in Sp1 siRNA-HepG2 cells,among which the mRNA expression of MRP3 mRNA de-creased 52%,the mRNA expression of MRP4 mRNA decreased 58%,the protein levels of MRP3 decreased 57%,and the protein levels of MRP4 decreased 60%.Conclusion Transcriptional factor Sp1 could regulate the expression of bile acids transporters MRP3 and MRP4 in HepG2 cells.

A Novel Decrease of Mrp3 Protein in Liver of β-Thalassemic Mouse.

Background: Hepatocytes have a fundamental system of efflux proteins that protect cells from toxic insults. Unconjugated bilirubin at higher concentration is toxic to cells and its intracellular accumulation is limited by the induction of efflux proteins such as Mrp3. In vivo studies showed an induction of hepatic Mrp3 expression in response to non-hemolytic hyperbilirubinemia as a compensatory mechanism to reduce UCB toxicity. Study Design: In the present study, we analyzed the hepatic Mrp3 expression profile during hemolytic hyperbilirubinemia. We used β-thalassemic mouse and WT rodents treated with phenylhydrazine as an animal model of chronic and acute hemolysis, respectively. Results: Unexpectedly, Mrp3 protein was 75% down-regulated in β-thalassemic mouse although Mrp3 mRNA was normal. Mrp3 mRNA was significantly induced in PHZ treated animals while again; Mrp3 protein was 60% down-regulated. Conclusion: For the first time we observed a clear down-regulation for hepatic Mrp3 protein that linked to hemolysis, not to bilirubin. We hypothesize that a similar decrease for hepatic Mrp3 proteins is occur in hemolytic patients such as β-thalassemia.

Psoralen induced bile acid accumulation and cytotoxicity by inhibiting MRP2 and MRP3 in HepG2 cells / 中国药理学通报

Aim To investigate the toxicity of isopsor-alen in HepG2 cells and its effects on bile acid, bile acid synthesis and transport. Methods Cell viability was evaluated by MTT assay and bile acid was deter-mined inside HepG2 cells, with exposure to various isopsoralen for 24h. The mRNA transcription of BSEP, MRP2, MRP3, NTCP, OATP2, OSTα, CYP7A1, CYP27 A1 , FXR and PXR were assessed by real-time PCR. Results The cell viability was decreased dose-dependently with isopsoralen in HepG2 cells, and IC50 was 118. 1μmol·L-1 exposure to isopsoralen for 24h. Bile acid inside cells significantly increased with 100 and 400 μmol · L-1 isopsoralen. Isopsoralen caused the down-regulation of MRP2 , MRP3 , CYP7 A1 mRNA at 25 μmol · L-1 . Beside these, the up-regulation of OATP2,OSTα,CYP27A1,FXR,PXR with 100 μmol· L-1 isopsoralen, but there was no significant change of BSEP and NTCP. Conclusion The results show that isopsoralen induces bile acid accumulation and cytotox-icity which may be associated with the down-regulation of MRP2, MRP3 in HepG2 cells.

Relationship between hepatic membrane protein MRP3 and nuclear receptor RXR? / 第三军医大学学报

Objective To investigate the relationship between the hepatic membrane protein MRP3(multidrug resistance-associated protein 3,MRP3) expression and the nuclear hormone receptor RXR?(retinoid-X receptor alpha,RXR?)expression in both cultured hepatoma cell HepG2 and bile duct ligated(BDL) rat liver.Methods Total cellular protein and nuclear protein were isolated from HepG2 cells induced by chenodeoxycholic acid(CDCA) or phenobarbital(PB),as well as from the liver tissue of BDL rats.The protein expressions of MRP3 and RXR? were determined by Western blotting.Results The membrane protein MRP3 expression was significantly enhanced and the nuclear receptor RXR? expression was suppressed by CDCA or PB in HepG2 cells.Similarly up-regulation of MRP3 and down-regulation of RXR? were also observed in BDL rat liver.Conclusion The up-regulation of hepatic membrane protein MRP3 may be associated with down-regulation of nuclear receptor RXR?.