Animals ; Autophagy/genetics* ; Cholesterol/metabolism* ; Gene Expression Regulation ; Integrases/metabolism* ; Leydig Cells/metabolism* ; Male ; Mice, Knockout ; Multienzyme Complexes/metabolism* ; Phosphoproteins/metabolism* ; Primary Cell Culture ; Progesterone Reductase/metabolism* ; RNA Splicing Factors/metabolism* ; Scavenger Receptors, Class B/metabolism* ; Sequestosome-1 Protein/metabolism* ; Signal Transduction ; Sirtuin 1/genetics* ; Sodium-Hydrogen Exchangers/metabolism* ; Steroid 17-alpha-Hydroxylase/metabolism* ; Steroid Isomerases/metabolism* ; Testosterone/genetics*

Pregnane X receptor (PXR) is key transcription factors which mainly regulate the expression of CYP3A genes. At the molecular level, PXR has been revealed the protection mechanism of the body against xenochemicals and a major mode of the drug-drug interactions. Besides playing an important role in drug metabolism and interactions, PXR and its target genes also play an important role in maintaining normal physiological function and homeostasis. Therefore, it is necessary to study the regulation of PXR and its related pharmacological effects of TCM and natural products, and to provide new clues for the new pharmacological pathway.
Animals ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression ; drug effects ; Humans ; Receptors, Steroid ; antagonists & inhibitors ; genetics ; metabolism

In order to study effects of ginseng on the metabolism of drug belong to CYP3A4 substrate, screening of pregnane X receptor activation from ginsenosides was performed by reporter assay. Based on PXR-CYP3A stable translation cell lines, 13 ginsenosides were screened for pregnane X receptor activation by reporter assays, and RIF as the positive control. The effect of ginsenosides Rg1 onCYP3A4 mRNA expression was also investigated by RT-PCR. The PXR-CYP3A stable translation cell lines had good response to RIF, and the EC50 is 2.51 micro mol x L(-1). When the condition of final concentration was 10 micromol x L(-1), ginsenoside F2 and protopanaxatriol had moderate inductive effects on PXR. Panaxotriol, Rg2, pseudoginsenoside F11, Rg1, ginsenoside and Rb3 had inhibitory effects on PXR. Ginsenoside Rf1, Rg3, Rh2 and protopanaxdiol had no obvious effects on PXR. Rg1 down-regulated CYP3A4 mRNA expression in a concentration-dependent manner. Activation of pregnane X receptor by ginsenosides may influence the metabolism of drug belong to CYP3A4 substrate, and cause ginseng-drug interactions.
Cytochrome P-450 CYP3A ; genetics ; metabolism ; Drug Interactions ; Ginsenosides ; pharmacology ; Hep G2 Cells ; Humans ; RNA, Messenger ; metabolism ; Receptors, Steroid ; agonists ; antagonists & inhibitors ; genetics ; Sapogenins ; pharmacology ; Transfection

This paper is to report the development of a high-throughput in vitro system to screen hPXR/CAR mediated CYP2B6 drug inducers, and the application of it into the quick determination of induction activity toward CYP2B6 by various commonly used traditional Chinese medicines (TCMs) extract. Dual reporter gene assays were performed. The hPXR/CAR expression vectors and the reporter vector pGL3-CYP2B6-Luc involved in the distal and proximal promoters of CYP2B6 were co-transfected into HepG2 cells. Relative luciferase activities in cell lysate were analyzed after 48 h treatment of blank vehicle or drugs to determine the induction activity toward CYP2B6 by various commonly used TCMs extract. The positive hPXR/hCAR activators rifampicin and CITCO were applied to make sure that the reporter gene model was successfully established. Then 5 kinds of commonly used TCM extracts and 1 herbal compound were successfully investigated, some were found to activate hPXR or hCAR and therefore have the potential to induce CYP2B6 enzyme. This is the first domestic article to report the hCAR3-mediated CYP2B6 induction model and the establishment of a reporter gene system for hPXR/CAR-mediated CYP2B6 induction can be an effective and systemic in vitro method to investigate the drug inducers of CYP2B6 and to explain the mechanism involved.
Aryl Hydrocarbon Hydroxylases ; genetics ; metabolism ; Cytochrome P-450 CYP2B6 ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Genes, Reporter ; Genetic Vectors ; Hep G2 Cells ; High-Throughput Screening Assays ; Humans ; Luciferases ; genetics ; metabolism ; Oximes ; pharmacology ; Plants, Medicinal ; chemistry ; Plasmids ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Receptors, Steroid ; genetics ; metabolism ; Rifampin ; pharmacology ; Thiazoles ; pharmacology ; Transfection

OBJECTIVETo define the effect of Curculiginis Rhizoma and its active ingredient orcinol glucoside on PXR-CYP3A of L02 cells in normal and deficiency-cold states, in order to lay a foundation for studies on the mechanism of efficacy expression differentiation of Curculiginis Rhizoma in different states.

METHODSerums of normal and deficiency-cold rats were adopted to culture L02 cells and induce cells in normal and deficiency-cold states. After aqueous extracts from Curculiginis Rhizoma and its active ingredient orcinol glucoside were used in cells in different states, PXR protain expression and CYP3A activity of L02 cells in normal and deficiency-cold states were observed.

RESULTMTT results showed that aqueous extracts from Curculiginis Rhizoma and orcinol glucoside could significantly enhance viability of L02 cells. Aqueous extracts from Curculiginis Rhizoma could significantly reduce PXR protein expression of L02 cells in normal state, while orcinol glucoside could significantly reduce CYP3A activity and PXR protein expression of L02 cells in normal state. Meanwhile, aqueous extracts from Curculiginis Rhizoma could significantly increase CYP3A activity and PXR protein expression of L02 cells in deficiency-cold state, while orcinol glucoside could significantly reduce CYP3A activity and increase PXR protein expression of L02 cells in deficiency-cold state.

CONCLUSIONCurculiginis Rhizoma can activate PXR and induce CYP3A activity of L02 cells in deficiency-cold state, but with no effect or even counteraction on PXR and its induced CYP3A of L02 cells in normal state.

Animals ; Cell Line ; Cytochrome P-450 CYP3A ; metabolism ; Gene Expression ; drug effects ; genetics ; Glucosides ; pharmacology ; Humans ; Male ; Plant Extracts ; chemistry ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Steroid ; metabolism ; Resorcinols ; pharmacology ; Rubiaceae ; chemistry

AIM: Silybin (SB), a major constituent of the milk thistle, has been used to treat several liver disorders. However, liver diseases were always accompanied by CYP450 dysfunction. This study was designed to explore the relationship between the hepatoprotective effect and CYP3A regulation of SB during thioacetamide (TAA)-induced rat liver injury. METHODS: Serum biochemical analysis and histopathological study were taken to evaluate the hepatoprotectinve effect of SB. α-SMA were detected by immunohistochemical analysis and cytokine release in rat liver was determined by ELISA assay. CYP3A and PXR expression were determined by RT-PCR and Western blot analysis, and CYP3A activity was based on the midazolam 4-hydroxylation reaction. Also, siRNA transfection was induced in HepG2 cells to evaluate the effect of PXR on cytotoxicity and CYP3A4 dysregulation caused by TAA. RESULTS: SB showed powerful hepatoprotective effects, and anti-inflammatory and anti-fibrosis effects, and reversed the loss of CYP3A and PXR in TAA-injured rat liver, and decreased PXR translocation into the cell nucleus. PXR silencing weakened the effect of SB on cytoprotection and CYP3A regulation. CONCLUSIONS PXR was a very important factor of CYP3A regulation and might be the target of SB in TAA-induced liver disease. Also, because of the potential interactions of SB and co-administered medicines, it might be necessary to adjust the dosage in the clinical medication of liver disease.
Animals ; Chemical and Drug Induced Liver Injury ; drug therapy ; enzymology ; Cytochrome P-450 CYP3A ; genetics ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Liver ; drug effects ; enzymology ; metabolism ; Male ; Milk Thistle ; chemistry ; Pregnane X Receptor ; Rats ; Rats, Sprague-Dawley ; Receptors, Steroid ; genetics ; metabolism ; Signal Transduction ; drug effects ; Silybin ; Silymarin ; administration & dosage ; Thioacetamide ; adverse effects

The study is to report the investigation of the effects of isorhamnetin on CYP3A4 and herb-drug interaction. A reporter gene assay is used to test pregnane X receptor transactivation action, qRT-PCR and a luminescence-based assay were applied to determine mRNA induction and enzyme activity of CYP3A4 after isorhamnetin treatment. The interaction of irinotecan and isorhamnetin was assessed by inhibition assay of cell proliferation. Isorhamnetin at 1, 10 and 25 micromol x L(-1) transactivated the CYP3A4 reporter construct and upregulated CYP3A4 mRNA as well in a dose-dependent manner. However, isorhamnetin had no effect on enzyme activity of CYP3A4 and irinotecan HepG2 cytotoxicity. In conclusion, activation of PXR by isorhamnetin played a role in the upregulation of CYP3A4 mRNA. Moreover, joint action of isorhamnetin with other drugs may not be associated with the herb-drug interaction.
Antineoplastic Agents, Phytogenic ; pharmacology ; Camptothecin ; analogs & derivatives ; pharmacology ; Cell Proliferation ; drug effects ; Cytochrome P-450 CYP3A ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Hep G2 Cells ; Herb-Drug Interactions ; Humans ; Quercetin ; administration & dosage ; analogs & derivatives ; pharmacology ; RNA, Messenger ; metabolism ; Receptors, Steroid ; metabolism ; Transcriptional Activation ; drug effects ; Up-Regulation

OBJECTIVETo test whether 7 herbs stimulate human pregnane X receptor (PXR)-mediated CYP3A4 transcription.

METHODTransient cotransfection reporter gene assays were performed with human PXR expression plasmids and a reporter plasmid containing the XRES in the CYP3A4 gene promoter in HepG2 cells.

RESULTThe aqueous extracts of Chrysanthemi Flos, Lycii Fructus, and Salviae Miltiorrhizae Radix et Rhizoma, and the methanol extracts of Chrysanthemi Flos, Crataegi Fructus, Lycii Fructus, Lonicerae Japonicae Flos, Dioscoreae Rhizoma,and Salviae Miltiorrhizae Radix et Rhizoma, activated human PXR-mediated transcription.

CONCLUSIONThe aqueous extracts of Chrysanthemi Flos, Lycii Fructus, and Salviae Miltiorrhizae Radix et Rhizoma, and the methanol extracts of Chrysanthemi Flos, Crataegi Fructus, Lycii Fructus, Lonicerae Japonicae Flos, Dioscoreae Rhizoma, and Salviae Miltiorrhizae Radix et Rhizoma are inducers of CYP3A4 by activating PXR, and thus may influence the metabolism of other substrates on CYP3A4.

Cell Line ; Chrysanthemum ; Crataegus ; Cytochrome P-450 CYP3A ; drug effects ; genetics ; metabolism ; Dioscorea ; Drugs, Chinese Herbal ; pharmacology ; Gene Transfer Techniques ; Genes, Reporter ; Hep G2 Cells ; Humans ; Lonicera ; Lycium ; Medicine, Chinese Traditional ; Plant Extracts ; pharmacology ; Receptors, Steroid ; drug effects ; genetics ; metabolism ; Salvia miltiorrhiza

OATP1B3, a member of SLC superfamily, is specifically expressed on the sinusoidal membrane of hepatocytes and is considered to be important in hepatic drug elimination. The overexpression of OATP1B3 was found recently in tumor tissues such as prostate, colon, and pancreatic tumors. Sequence variations in SLCO1B3 gene, such as SNPs, have been described and a common haplotype consisting of 334T>G and 699G>A SNPs is related to altered transport characteristics of OATP1B3. OATP1B3 is of relevance to drug metabolism through affecting alteration of hepatic concentration of endo- and xenobiotic compounds that interact with nuclear receptors such as PXR and CAR, and thereby directly alter the extent of target gene transcription, including major CYP isoenzymes such as CYP3A4. This review will provide an overview of substrates and inhibitors of OATP1B3 and subsequently to assess the effect of genetic mutation on transport activity. The studies linking OATP1B3 with cancer clinical outcomes are also discussed in this review.
Animals ; Biological Transport ; Cytochrome P-450 CYP3A ; metabolism ; Drug Interactions ; Gene Expression Regulation, Neoplastic ; Gene Frequency ; Hepatocytes ; metabolism ; Humans ; Liver ; metabolism ; Neoplasms ; metabolism ; Organic Anion Transporters, Sodium-Independent ; antagonists & inhibitors ; chemistry ; genetics ; Polymorphism, Single Nucleotide ; RNA, Messenger ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Receptors, Steroid ; metabolism ; Solute Carrier Organic Anion Transporter Family Member 1B3

OBJECTIVETo screen a group of traditional Chinese medicines with effect on pregnane X receptor (PXR)-mediated transcription regulation of P450 3A4 (CYP3A4); and to study whether they can induce the expression of CYP3A4 with a dose, time-dependent manner.

METHODTransient cotransfection reporter gene assays were performed with pCI-hPXR-neo, pGL3-CYP3A4-Luc and beta-galactosidase expression plasmid in HepG2 cells.

RESULTRhizoma Curcumae, Atractylodes lancea, A. macrocaphala and Poria cocos could induce transcriptional expression of CYP3A4. In the dose-effect study, 24 h after induction, 500 mg x L(-1) Rhizoma Curcumae, A. lancea, A. macrocaphala and Poria cocos, respectively, could induce the CYP3A4 gene expression with (6.82 +/- 0.09), (6.76 +/- 0.20), (5.49 +/- 0.13) and (4.97 +/- 0.07) folds, as compared with 0.1% DMSO treated cells. In the time-effect study, 500 mg x L(-1) Rhizoma curcumae, A. lancea, A. macrocaphala and Poria cocos for 48 h could induce the CYP3A4 gene expression with (7.74 +/- 0.54), (7.34 +/- 0.10), (5.54 +/- 0.11) and (5.32 +/- 0.18) folds, compared with 0.1% DMSO treated cells.

CONCLUSIONRhizoma Curcumae, A. lancea, A. macrocaphala and Poria cocos could induce the expression of CYP3A4 gene transcription through activating PXR.

Cell Line, Tumor ; Cytochrome P-450 CYP3A ; genetics ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Receptors, Steroid ; metabolism ; Transcription, Genetic ; drug effects