Activating Effect of Effective Components in Medicinal and Edible Substances on Human Pregnane X Receptor and Cytotoxicity Screening / 中国实验方剂学杂志

ObjectiveTo explore the activating effects of ten important effective components in seven medicinal and edible substances on human pregnane X receptor （PXR）， including Glycyrrhizae Radix et Rhizoma （liquiritin and glycyrrhizic acid）， Houttuyniae Herba （quercetin and houttuyfonate）， Prunellae Spica （rosmarinic acid）， Cassiae Semen （aurantio-obtusin）， Poria （pachymic acid）， Lilii Bulbus （Lilium brownii saponin and colchicine）， and Lycii Fructus （Lycium barbarum polysaccharide） and screen potentially toxic components. MethodCell counting kit-8 （CCK-8） assay was used to investigate the cytotoxic effect of liquiritin， glycyrrhizic acid， quercetin， houttuyfonate， rosmarinic acid， pachymic acid， aurantio-obtusin， and colchicine （10， 20， and 50 μmol·L-1）， and L. brownii saponin and L. barbarum polysaccharide （10， 20， and 50 mg·L-1） on normal human hepatocyte cell line （L02）. The release of lactate dehydrogenase （LDH） in L02 cells after drug treatments was detected by the biochemical analyzer. The apoptosis induced by ten effective components was explored by Hoechst 33342 staining. The secreted luciferase reporter system was used to co-transfect the PXR expression vector and reporter gene vector containing cytochrome P450 3A4 （CYP3A4） transcriptional regulatory region into L02 cells， with 10 μmol·L-1 rifampicin （RIF） as a positive control. After treated with liquiritin， glycyrrhizic acid， quercetin， houttuyfonate， rosmarinic acid， aurantio-obtusin， pachymic acid， and colchicine （5， 10， and 20 μmol·L-1） and L. brownii saponin and L. barbarum polysaccharide （5， 10， and 20 mg·L-1） for 24 h， the cells were tested for secreted luciferase activity. ResultCompared with the control group， colchicine， L. brownii saponin， and quercetin decreased the cell viability （P<0.05， P<0.01）. Compared with the control group， quercetin， rosmarinic acid， glycyrrhizic acid， colchicine， aurantio-obtusin， and pachymic acid increased the release rate of LDH in L02 cells （P<0.05， P<0.01）. The proportion of hyperchromatic nuclei increased gradually after rosmarinic acid， liquiritin， and L. barbarum polysaccharide treatments as compared with the control group （P<0.05， P<0.01）. In terms of co-transfection of pcDNA3.1-PXR and pGLuc-CYP3A4 into L02 cells， compared with the control group， aurantio-obtusin and pachymic acid showed activating effects on PXR （P<0.05）， whereas liquiritin and glycyrrhizic acid showed inhibitory effects （P<0.05）. ConclusionThe findings suggest that when medicinal and edible substances are taken for a long time， attention should be paid to their influence on drug-metabolizing enzymes and possible interactions， so as to improve their safety.

Preliminary association of individual different plasma pazopanib concentration with CYP3A4 gene polymorphism / 中国临床药理学与治疗学

AIM: To study the pharmacokinetics (PK) of pazopanib tablets and explore the genetic mechanism of individual differences in drug metabolism primarily. METHODS: Fourteen healthy male subjects were respectively administrated with a single dose pazopanib tablet (200 mg) orally on the day of dosing, and their blood samples were collected from baseline to 96 hours. The serum concentration of pazopanib was measured by LC-MS/MS, the parameters of PK were calculated by winnonlin 6.3 software, and the gene polymorphism of cytochrome P450 3A4 (CYP3A4) was determined by snapshot method. RESULTS: The range of C

P-glycoprotein associated with diabetes mellitus and survival of patients with pancreatic cancer: 8-year follow-up

Diabetes mellitus (DM) has a high prevalence in patients with pancreatic cancer (PaC), but the prognostic value of DM in PaC remains controversial. Alterations of P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4) contribute to multidrug resistance and intestinal metabolism in a variety of cancer types, which may be implicated in DM development. This study aimed to explore the potential prognostic value of P-gp and CYP3A4 in PaC patients in the context of DM through long-term follow-up. We retrospectively reviewed the medical records of patients with PaC admitted at The First People's Hospital of Changzhou, Jiangsu, China, from January 2011 to November 2019 and identified two cohorts of adult patients with PaC, including 24 with DM and 24 without DM (non-DM). The baseline clinical characteristics and outcomes were compared. Immunohistochemistry showed that protein expression of P-gp, but not CYP3A, in duodenum tissues was significantly upregulated in PaC patients with DM compared with those without DM. Kaplan-Meier analysis and log-rank test showed that the survival of patients with PaC and DM/high expression of P-gp was not significantly reduced compared with that of patients without DM/low expression of P-gp. These findings suggested that P-gp expression levels were different in the DM and non-DM groups of patients with PaC, but DM and duodenal P-gp levels were not associated with the long-term survival of patients with PaC. It appears that the presence of DM or P-gp expression levels may not serve as effective prognostic markers for PaC.

The 3'-untranslated region contributes to the pregnane X receptor (PXR) expression down-regulation by PXR ligands and up-regulation by glucocorticoids

Pregnane X receptor (PXR) is the major regulator of xenobiotic metabolism. PXR itself is controlled by various signaling molecules including glucocorticoids. Moreover, negative feed-back regulation has been proposed at the transcriptional level. We examined the involvement of the 3'-untranslated region (3'-UTR) of mRNA and microRNAs in PXR- and glucocorticoid receptor (GR)-mediated regulation of gene expression. PXR ligands were found to significantly downregulate mRNA expression in a set of 14 human hepatocyte cultures. Similarly, PXR was downregulated by PCN in the C57/BL6 mice liver. In mechanistic studies with the full-length 3'-UTR cloned into luciferase reporter or expression vectors, we showed that the 3'-UTR reduces PXR expression. From the miRNAs tested, miR-18a-5p inhibited both expression and gene induction. Importantly, we observed significant upregulation of miR-18a-5p expression 6 h after treatment with the PXR ligand rifampicin, which indicates a putative mechanism underlying negative feed-back regulation in hepatic cells. Additionally, glucocorticoids upregulated expression not only through the promoter region but also 3'-UTR regulation, which likely involves downregulation of miR-18a-5p. We conclude that miR-18a-5p is involved in the down-regulation of expression by its ligands and in the upregulation of mRNA expression by glucocorticoids in hepatic cells.

Effects of pargyline on histone methylation in promoter and enhancer regions and transcription of CYP3A4/3A7 / 药学学报

This study was designed to investigate effects of pargyline on histone methylation in the promoter and enhancer regions and transcription of cytochrome P450 3A4/3A7 (CYP3A4/3A7) gene. Human primary fetal liver cells were isolated, cultured and randomly divided into several groups including control, solvent, pargyline low, middle, high dose (treated with 0.6, 1.2, 2.4 mmol·L-1). HepG2 cells were cultured and treated with 0.03, 0.3, 3 mmol·L-1 pargyline. After 48 hours, total RNAs were prepared from the cells to determine the expression of CYP3A mRNA in primary fetal cells and HepG2 cells with real-time quantative PCR (qPCR). HepG2 cells were cultured and then treated with 3 mmol·L-1 pargyline for 48 hours. The chromatin immunoprecipitation (ChIP) assay was performed with dimethylation of histone H3 at lysine 4 (H3K4me2), and IgG antibodies respectively. The precipitated DNA was resuspended and used for qPCR. Primers were used to detect different regions of CYP3A4/3A7 promoter and enhancer. Occupancy of H3K4me2 was shown as percent of input DNA relative to control cells. The results suggested that pargyline has an effect on primary fetal liver cells and HepG2 cells proliferation. The level of CYP3A7 was markedly enhanced in human primary fetal liver cells by treatment with 1.2, 2.4 mmol·L-1 of pargyline (P-1 of pargyline in HepG2 cells (P<0.001) compared with solvent control. Occupancy of H3K4me2 on human CYP3A4 promoter (-362 to +53) and enhancer segment (-7 836 to -6 093) harbored the overlapping hepatocyte nuclear factors 4A (HNF4A) binding site compared with a negative control. Occupancy of H3K4me2 on human CYP3A7 promoter (-163 to +103) and enhancer segment (-4 054 to -3 421, -6 265 to -6 247) overlapped with glucocorticoid receptor (GR) binding site. In conclusion, the enriched H3K4me2 in the promoter and enhancer regions was induced by pargyline with HNF4A or GR binding site in CYP3A4/3A7 gene to activate the corresponding genes.

Ginkgolide B induces CYP3 A4 expression through activation of human pregnane X receptor / 中国药理学通报

Aim To study the induction effect of Ginkgolide B on CYP3A4,and further verify the role of pregnane X receptor in CYP3 A4 induction expres-sion. Methods With different concentrations of Ginkgolide B treatment on LS174T cells,the CYP3A4 mRNA expression was detected by Q-PCR assay,fur-ther PXR-CYP3 A4 stable translation HepG2 cell lines were used to test the effect of Ginkgolide B on activity of PXR by reporter gene screening assay.CYP3A4 protein expression was detected by Western blot.PXR was knocked down with transfected with siRNA, CYP3 A4 mRNA and protein were detected in the con-dition of PXR low expression.Results The results revealed that the level of CYP 3 A 4 gene and protein expression were significantly increased by Ginkgolide B,and there was no induction effect on PXR.Reporter gene screening showed that Ginkgolide B could en-hance the transcriptional activity of PXR in a concen-tration-dependent manner.Under conditions of low ex-pression of PXR ,Ginkgolide B could also increase ex-pression of CYP3A4,but the induction folds were low-er than those of normal PXR group.Conclusion Ginkgolide B can signicantly up-regulate CYP3 A4 ex-pression via the PXR-CYP3 A4 pathway,and it has no effects on PXR gene expression.

Effect of Atorvastatin and Clopidogrel Co-Administration After Coronary Stenting in Korean Patients With Stable Angina

BACKGROUND AND OBJECTIVES: It was reported that atorvastatin co-administered with clopidogrel for 8 months did not affect the anti-platelet potency of clopidogrel in Korean patients with acute coronary syndrome, but not in patients with stable angina. We investigated whether co-administration of statins with clopidogrel affected the anti-platelet efficacy of clopidogrel in Korean patients with stable angina. SUBJECTS AND METHODS: This was a randomized, open-label and two-period crossover design study conducted at two centers. Two hundreds thirty three patients with stable angina scheduled for coronary stenting were randomized into two groups. In Group A, 119 patients first received atorvastatin (10 mg) followed by fluvastatin (80 mg) for 12 weeks per treatment. In Group B, 114 patients received the same treatments in reverse order. RESULTS: Baseline adenosine diphosphate (ADP, 10 micromol/L)-induced platelet aggregation was 54.4+/-9.1% in Group A and 53.8+/-9.0% in Group B (p=0.44), and significant differences were noted after each treatment period (p<0.001). Inhibition of platelet aggregation was similar between Group A and Group B at 24 hours following clopidogrel loading (29.2+/-11.0% vs. 30.4+/-12.7%; p=0.42). The two treatment least square means of 12-week ADP (10 mol/L)-induced platelet aggregation [29.50+/-0.79 {standard error (SE)}% on the atorvastatin treatment group vs. 28.16+/-0.70 (SE)% in the fluvastatin treatment group] in a 2x2 cross-over study were not significantly different (p=0.204). CONCLUSION: Statin and clopidogrel co-administration for 12 weeks is not associated with attenuated anti-platelet activity of clopidogrel in Korean patients with stable angina after coronary stenting, in support of the findings of similar studies conducted in Caucasian populations.

Association between cytochrome P450 3A4 gene 894C>T single nucleotide polymorphism and clopidogrel resistance / 解放军医学杂志

T was genotyped by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)in all the patients.Results The occurrence of CR in this population was 23.3%(70/300).There was CYP3A4 894C/T polymorphism in the study population.The frequencies of the three kinds of genotypes(CC,CT,TT)in CR group and non-CR(NCR)group were 45.7%,50.0%,4.3% and 63.5%,31.7%,4.8%,respectively.The frequency of TT genotype was significantly higher in NCR group than that in CR group(OR=2.06,95% CI:1.201-3.547,P=0.020).C allele carriers were more likely to develop clopidogrel resistance compared with that of T allele carriers(OR=1.59,95% CI:1.037-2.442,P=0.023).Conclusion CYP3A4 gene 894C/T polymorphism is associated with the risk of CR,and C allele carriers may be a possible genetic susceptibility factor for patients with CR.