Xiaobo Yang

Dasatinib reverses the multidrug resistance of breast cancer MCF-7 cells to doxorubicin by downregulating P-gp expression via inhibiting the activation of ERK signaling pathway.

Multidrug resistance (MDR) is one of the major obstacles to the efficiency of cancer chemotherapy, which often results from the overexpression of drug efflux transporters such as P-glycoprotein (P-gp). In the present study, we determined the effect of dasatinib which was approved for imatinib resistant chronic myelogenous leukemia (CML) and (Ph+) acute lymphoblastic leukemia (ALL) treatment on P-gp-mediated MDR. Our results showed that dasatinib significantly increased the sensitivity of P-gp-overexpressing MCF-7/Adr cells to doxorubicin in MTT assays; thus lead to an enhanced cytotoxicity of doxorubicin in MCF-7/Adr cells. Additionally, dasatinib increased the intracellular accumulation, inhibited the efflux of doxorubicin in MCF-7/Adr cells, and significantly enhanced doxorubicin-induced apoptosis in MCF-7/Adr cells. Further studies showed that dasatinib altered the expression levels of mRNA, protein levels of P-gp, and the phosphorylation of signal–regulated kinase (ERK) both in time-dependent (before 24 h) and dose-dependent manners at concentrations that produced MDR reversals. In conclusion, dasatinib reverses P-gp-mediated MDR by downregulating P-gp expression, which may be partly attributed to the inhibition of ERK pathway. Dasatinib may play an important role in circumventing MDR when combined with other conventional antineoplastic drugs.

Protective Effects of Calycosin Against CCl4-Induced Liver Injury with Activation of FXR and STAT3 in Mice

PurposeInvestigating the hepatoprotective effect of calycosin against acute liver injury in association with FXR activation and STAT3 phosphorylation.MethodsThe acute liver injury model was established by intraperitoneal injection of CCl4 in C57BL/6 mice. Serum alanine aminotransferase, aspartate aminotransferase, HE staining and TUNEL assay were used to identify the amelioration of the liver histopathological changes and hepatocytes apoptosis after calycosin treatment. ELISA kit and 5-bromo-2-deoxyuridine immunohistochemistry were used to measure the liver bile acid concentration and hepatocyte mitotic rate in vivo. The relation between calycosin and activation of FXR and STAT3 was comfirmed using the Luciferase assay, Molecular docking, Real-time PCR and Western Blot in vitro.ResultsThe liver histopathological changes, hepatocytes apoptosis, liver bile acid overload and hepatocyte mitosis showed significant changes after calycosin treatment. Calycosin promoted the expression of FXR target genes such as FoxM1B and SHP but the effect was reversed by FXR suppressor guggulsterone. Molecular docking results indicated that calycosin could be embedded into the binding pocket of FXR, thereby increasing the expressions of STAT3 tyrosine phosphorylation and its target genes, Bcl-xl and SOCS3.ConclusionsCalycosin plays a critical role in hepatoprotection against liver injury in association with FXR activation and STAT3 phosphorylation.

Enhancement effect of resveratrol on the intestinal absorption of bestatin by regulating PEPT1, MDR1 and MRP2 in vivo and in vitro.

The purpose of present study was to assess the enhancing effect of resveratrol (Res) on the absorption of bestatin and clarify the related molecular mechanism. Res facilitated bestatin absorption by down-regulating both protein and gene levels of multidrug resistance 1 (Mdr1) and Multidrug resistance-associated protein 2 (Mrp2), and up-regulating oligopeptide transporter 1 (Pept1) protein and mRNA expression in rat intestine. In the same manner, Res increased penetration of bestatin via significantly activating mRNA and protein expression of PEPT1 in Caco-2 cells. Conversely, mRNA and protein expression levels of MDR1, MRP2 and phosphorylation level of Insulin-like growth factor 1 receptor (IGF-1R) were inhibited by Res in Caco-2 cells. Moreover, Res also altered the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT). Res enhanced the intracellular concentration of bestatin by down-regulating MDR1 and MRP2 expression through a mechanism that involves IGF-1R/AKT/ERK signaling pathway inhibition in Caco-2 cells. In conclusion, Res enhances bestatin absorption by regulating PEPT1, MDR1 and MRP2 both in vivo and in vitro.

P-gp, MRP2 and OAT1/OAT3 mediate the drug-drug interaction between resveratrol and methotrexate.

The purpose of present study was to investigate the effect of resveratrol (Res) on altering methotrexate (MTX) pharmacokinetics and clarify the related molecular mechanism. Res significantly increased rat intestinal absorption of MTX in vivo and in vitro. Simultaneously, Res inhibited MTX efflux transport in MDR1-MDCK and MRP2-MDCK cell monolayers, suggesting that the target of drug interaction was MDR1 and MRP2 in the intestine during the absorption process. Furthermore, there was a significant decrease in renal clearance of MTX after simultaneous intravenous administration. Similarly, MTX uptake was markedly inhibited by Res in rat kidney slices and hOAT1/3-HEK293 cell, indicating that OAT1 and OAT3 were involved in the drug interaction in the kidney. Additionally, concomitant administration of Res decreased cytotoxic effects of MTX in hOAT1/3-HEK293 cells, and ameliorated nephrotoxicity caused by MTX in rats. Conversely, intestinal damage caused by MTX was not exacerbated after Res treatment. In conclusion, Res enhanced MTX absorption in intestine and decreased MTX renal elimination by inhibiting P-gp, MRP2, OAT1 and OAT3 in vivo and in vitro. Res improved MTX-induced renal damage without increasing intestinal toxicity.

Dioscin enhances methotrexate absorption by down-regulating MDR1 in vitro and in vivo

The purpose of this study was to investigate the enhancing effect of dioscin on the absorption of methotrexate (MTX) and clarify the molecular mechanism involved in vivo and in vitro. Dioscin increased MTX chemosensitivity and transepithelial flux in the absorptive direction, significantly inhibiting multidrug resistance 1 (MDR1) mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activities in Caco-2 cells. Moreover, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Dioscin enhanced the intracellular concentration of MTX by down-regulating MDR1 expression through a mechanism that involves NF-κB signaling pathway inhibition in Caco-2 cells. Dioscin strengthened MTX absorption by inhibiting MDR1 expression in rat intestine. In addition, even though MTX is absorbed into the enterocytes, there was no increase in toxicity observed, and that, in fact, decreased toxicity was seen.

PEPT1- and OAT1/3-mediated drug-drug interactions between bestatin and cefixime in vivo and in vitro in rats, and in vitro in human.

The purpose of the present study was to elucidate the transporter-mediated pharmacokinetics mechanism of drug-drug interactions (DDIs) between bestatin and cefixime. The plasma concentrations and bioavailabilities of bestatin and cefixime were decreased after oral co-administration in rats. The uptake in rat everted intestinal sacs of bestatin and cefixime were dramatically declined after co-administration of the two drugs. Bestatin and cefixime can mutually competitively inhibit the uptake by hPEPT1-HeLa cells. The plasma concentrations of bestatin and cefixime were increased; however, the cumulative biliary excretion had no significant change, and the cumulative urinary excretion and renal clearance of the two drugs in rats decreased after intravenous coadministration. Moreover, decreased uptake of the two drugs was observed in human kidney slices, rat kidney slices and hOAT1/hOAT3-transfected HEK293 cells when bestatin and cefixime were coadministered. The accumulation of bestatin and cefixime in kidney slices can be inhibited by p-aminohippurate, benzylpenicillin and probenecid, but not by tetraethyl ammonium. The results suggest that intestinal absorption and renal excretion of bestatin and cefixime can be inhibited when the two drugs were co-administered in rats. The pharmacokinetic mechanism indicates that the DDIs between bestatin and cefixime are mainly mediated by Pept1 and Oat1/3 in rats. PEPT1 and OAT1/3 are the target transporters of DDIs between bestatin and cefixime in human kidney slices and human transfected cells, proposing possible drug-drug interaction in humans.

Calycosin attenuates triglyceride accumulation and hepatic fibrosis in murine model of non-alcoholic steatohepatitis via activating farnesoid X receptor

BACKGROUND Non-alcoholic steatohepatitis (NASH) represents the more severe end of hepatic steatosis and is associated with progressive liver disease. Calycosin, derived from the root of Radix Astragali, has been demonstrated to have favorable efficacy on acute liver injury. PURPOSE The present study was to investigate the hepatoprotective effect of calycosin on attenuating triglyceride accumulation and hepatic fibrosis, as well as explore the potential mechanism in murine model of NASH. STUDY DESIGN The C57BL/6 male mice were fed with methionine choline deficient (MCD) diet for 4 weeks to induce NASH and treated with or without calycosin by oral gavage for 4 weeks. METHODS The body weight, liver weight and the liver to body weight ratios were measured. Serum ALT, AST, TG, TC, FFA, MCP-1 and mKC levels were accessed by biochemical methods. H&E staining and Oil red O staining were used to identify the amelioration of liver histopathology. Immunohistochemistry of a-SMA, Masson trichrome staining and Sirius red staining were used to identify the amelioration of hepatic fibrosis. The quantitative real-time-PCR and Western blot were applied to observe the expression changes of key factors involved in triglyceride synthesis, free fatty acid β-oxidation and hepatic fibrosis. RESULTS Calycosin significantly inhibited body weight loss induced by MCD diet, decreased the ALT and AST activities, MCP-1 and mKC in a dose-dependent manner. The H&E and Oil red O staining indicated calycosin effectively improved hepatic steatosis, improved the degree of triglyceride accumulation. Masson trichrome and Sirius red staining indicated that calycosin treatment remarkably attenuated the degree of hepatic fibrosis. Immunohistochemistry of a-SMA demonstrated that calycosin attenuated hepatic fibrosis by inhibiting hepatic stellate cell activation. Further, calycosin inhibited the expression of SREBP-1c, FASN, ACC and SCD1 involved in triglyceride synthesis, promoted the expression of PPARa, CPT1, Syndecan-1 and LPL involved in free fatty acid β-oxidation. The above effects of calycosin were attributed to FXR activation. CONCLUSION Calycosin attenuates triglyceride accumulation and hepatic fibrosis to protect against NASH via FXR activation.

Bezafibrate–mizoribine interaction: Involvement of organic anion transporters OAT1 and OAT3 in rats

A patient with rheumatoid arthritis developed rhabdomyolysis while undergoing treatment with mizoribine concomitantly with bezafibrate. The symptoms rapidly disappeared and laboratory test results normalized when she discontinued the two drugs. The purpose of the present study was to elucidate the transporter-mediated molecular pharmacokinetic mechanisms of drug-drug interactions between bezafibrate and mizoribine. Comparing bezafibrate-mizoribine group with bezafibrate group, the Tmax and Cmax of bezafibrate were essentially unchanged in rats. The AUC of bezafibrate was significantly increased and t1/2β was prolonged markedly with an obviously reduction in plasma clearance and cumulative urinary excretion. The changes were similar to oral studies following intravenous co-administration. In rat kidney slices, the uptake of bezafibrate was markedly inhibited by p-aminohippurate, benzylpenicillin and probenecid but not by tetraethyl ammonium. Mizoribine not only decreased the uptake of bezafibrate, but also inhibited the uptake of p-aminohippurate and benzylpenicillin. The uptakes of bezafibrate and mizoribine were significantly higher compared to vector-HEK293 cells. The uptakes of bezafibrate and mizoribine in highest concentration were increased 1.63 and 1.46 folds in hOAT1-transfected cells, 1.43 and 1.24 folds in hOAT3-transfected cells, respectively. The Km values of bezafibrate uptake by hOAT1/3hOAT1-/hOAT3-HEK293 K293 cells were increased 1.68 fold in hOAT1-HEK293 cell and 2.12 fold in hOAT3-HEK293 cell in the presence of mizoribine with no change of Vmax. It indicated that mizoribine could inhibit the uptake of bezafibrate by hOAT1/3-HEK293 cells in a competitive way. In conclusion, OAT1 and OAT3 are the target transporters of drug-drug interactions between bezafibrate and mizoribine in pharmacokinetic aspects.

Yangonin protects against cholestasis and hepatotoxity via activation of farnesoid X receptor in vivo and in vitro

ABSTRACT Cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Recently obeticholic acid (OCA) which is a farnesoid X receptor (FXR) agonist was approved by FDA to treat cholestatic liver diseases, which provided us a newly therapeutic strategy against cholestasis. The purpose of the current study is to screen novel FXR agonists and verify the anti‐cholestasis effect of yangonin in vivo and in vitro. The computational strategy of two‐dimensional virtual screening was used to search for new FXR agonists, and dual‐luciferase reporter gene assay was used to further demonstrate FXR activation by yangonin. Then, the hepatoprotective effect of yangonin via FXR activation against cholestasis and hepatotoxity was evaluated in mice and was investigated using FXR silence in cells. Yangonin was found to activate FXR to exert hepatoprotective effect against cholestatic liver injury. Dynamic change analysis of bile acids and gene analysis revealed that yangonin promoted bile acid efflux into bile and reduced hepatic uptake via the regulation of FXR‐target genes Bsep, Mrp2 and Ntcp expression. Furthermore, yangonin modulated enzymes involved in bile acid synthesis and metabolism including Cyp7a1 Cyp8b1 and Sult2a1. In addition, yangonin promoted liver repair and suppressed liver inflammation. However, the changes in these genes and protein, as well as ameliorative liver histology induced by yangonin were abrogated by FXR antagonist guggulsterone in vivo and FXR siRNA in vitro. Yangonin produces protective effect against cholestasis via FXR activation. Yangonin may be an effective approach for the prevention and treatment for cholestatic liver diseases. Graphical abstract Figure. No Caption available. HighlightsYangonin protects against ANIT‐induced cholestatic liver injury via FXR activation.Yangonin decreases hepatic uptake and increase efflux of bile acids.Yangonin reduces bile acid synthesis in liver and increases bile acid metabolism.Yangonin promotes liver repair through an induction in liver regeneration‐related genes.Yangonin suppresses liver inflammation through repressing inflammation‐related genes.

Organic anion transporters 1 (OAT1) and OAT3 meditated the protective effect of rhein on methotrexate-induced nephrotoxicity

Rhein is identified as a major metabolite of diacerein, a prodrug used in the treatment of osteoarthritis. Methotrexate (MTX) is a highly toxic drug with a low therapeutic index. MTX and diacerein are used concomitantly in clinical practice for the treatment of rheumatoid arthritis. The purpose of this study was to investigate organic anion transporters (OAT)-mediated effect of rhein on the disposition of MTX, as well as to clarify the changes in nephrotoxicity of MTX when given rhein together. Concomitant administration of rhein could strongly increase the systemic exposure in rats. Similarly, MTX accumulation was markedly inhibited by rhein in rat kidney slices and hOAT1/3-HEK293 cell, indicating that OAT1 and OAT3 were involved in the drug–drug interaction (DDI) in the kidney. Additionally, concomitant administration of rhein attenuated cytotoxic effects of MTX in hOAT1/3-HEK293 cells, and alleviated nephrotoxicity caused by MTX in rats. In conclusion, rhein decreased renal elimination of MTX by inhibiting OAT1 and OAT3, and alleviated MTX-induced renal toxicity in vivo.