Cucurbitacin B suppresses proliferation of pancreatic cancer cells by ceRNA: Effect of miR-146b-5p and lncRNA-AFAP1-AS1.

Cucurbitacin B (CuB) is a natural tetracyclic triterpene product that displays antitumor activity against a wide variety of cancers. In this study, we explored the antipancreatic cancer activity of CuB via the inhibition of expression of the cancer-related long noncoding RNA, actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1). CuB arrested pancreatic cancer (PC) cells in the G2/M cell cycle phase by suppressing the expression of AFAP1-AS1. Insights into the mechanisms of competing endogenous RNAs (ceRNAs) gained from bioinformatics analysis and luciferase activity assays showed that the epidermal growth factor receptor (EGFR) and AFAP1-AS1 directly compete for miR-146b-5p binding. CuB-induced high miR-146b-5p expression and inhibited the expression of AFAP1-AS1. In summary, reducing the expression of endogenous AFAP1-AS1 effectively increased the available concentration of miR-146b-5p in PC, whereas miR-146b-5p overexpression prevented the expression of endogenous AFAP1-AS1. In particular, we hypothesized that AFAP1-AS1 might act as a ceRNA, effectively becoming a sponge for miR-146b-5p, thereby activating the expression of the EGFR. Thus, CuB suppresses the proliferation, in vitro and in vivo, of PC cells through the ceRNA effect of AFAP1-AS1 on miR-146b-5p.

Dosage Optimization Based on Population Pharmacokinetic Analysis of Tacrolimus in Chinese Patients with Nephrotic Syndrome.

PURPOSE: The objective of this study was to merge genetic and non-genetic factors of tacrolimus pharmacokinetics to establish a more stable population pharmacokinetic model for individualized dosage regimen in Chinese nephrotic syndrome patients. METHODS: Nephrotic syndrome patients (>16 years old) treated with tacrolimus were included in the study. The population pharmacokinetic approach was analyzed using NONMEM version 7.3.0 software. Monte Carlo simulations were performed to optimize the dosage according to the population pharmacokinetic parameters of tacrolimus. RESULTS: The mean apparent clearance (CL/F) of tacrolimus was 13.4 L/h, with an inter-individual variability of 22.4%. The CL/F of tacrolimus in Wuzhi tablets co-administration and CYP3A5 non-expresser groups were 19.3% and 19.1% lower than that of the non-Wuzhi tablets and CYP3A5 expresser groups, respectively. The NR1I2 rs2276707 TT variant carriers had 1.17-fold CL/F compared to the CC/CT variant carriers. Monte Carlo simulation showed that the nephrotic syndrome patients that were CYP3A5 non-expressers or co-administered Wuzhi tablets received 50% or 33.3% lower dose of tacrolimus to reach the target concentration. In contrast, the NR1I2 rs227707 TT genotype carriers were administered a 33.3% higher dose of tacrolimus than the NR1I2 rs227707 CC/CT genotype carriers. CONCLUSIONS: A new population pharmacokinetic model was established to describe the pharmacokinetics of tacrolimus in nephrotic syndrome patients, which can be used to select rational dosage regimens to achieve a desirable whole-blood concentration.

A Population Pharmacokinetic-Pharmacogenetic Model of Lamotrigine in Chinese Children With Epilepsy.

BACKGROUND: The pharmacokinetics of lamotrigine (LTG) is complex and varies significantly among individuals, especially among children. Therefore, this study aimed to establish a population pharmacokinetic (PPK) model of LTG in Chinese children with epilepsy and to comprehensively evaluate the effects of genetic variations in drug-metabolizing enzymes, transporters, and a transcriptional regulator on LTG pharmacokinetics. METHODS: Three hundred eighty-five steady-state plasma concentrations were obtained from 179 children (age 10.72 ± 3.05 years and body weight 46.23 ± 17.77 kg) with epilepsy during therapeutic drug monitoring. These patients were divided into the PPK-model group (n = 121) and the PPK-validation group (n = 58) and were genotyped for UGT1A4, UGT2B7, ABCB1, ABCG2, SLC22A1, and HNF4α. PPK analysis was performed by nonlinear mixed effects modeling. RESULTS: In the final model, apparent clearance (CL/F) of LTG was estimated to be 1.48 L/h; 500 mg valproic acid, oxcarbazepine, and UGT2B7-161TT genotype changed the CL/F by -46.2, +31.1, and -21.8%, respectively. Body weight was also identified as a significant covariate affecting LTG CL/F. CONCLUSIONS: A PPK-pharmacogenetic model of LTG in Chinese children with epilepsy was successfully established with nonlinear mixed effects modeling. Genotyping for UGT2B7-161C>T may be useful in titrating the optimal LTG dose.

Population pharmacokinetics of lamotrigine co-administered with valproic acid in Chinese epileptic children using nonlinear mixed effects modeling.

PURPOSE: The aims of this study were to develop a population pharmacokinetic (PPK) model of lamotrigine (LTG) in Chinese epileptic children by using nonlinear mixed effects modeling (NONMEM) and to investigate the effects of valproic acid (VPA) and genetic polymorphisms of the major metabolizing enzymes (UGT1A4, UGT2B7) on the pharmacokinetics of LTG. METHODS: A total of 182 epileptic children who were treated with LTG as monotherapy or as part of combination therapy were included in this study as the model group, and 61 patients were included as the validation group. The steady-state serum trough concentrations of LTG and VPA were determined using a high-performance liquid chromatography method and fluorescence polarization immunoassay, respectively. Patients were genotyped for three single nucleotide polymorphisms (UGT1A4 142T>G, UGT2B7 -161C>T, and UGT2B7 802C>T). PPK analysis was performed with NONMEM using first-order absorption and elimination. Bootstrap, normalized prediction distribution errors and external evaluations were performed to determine the stability and predictive performance of the model. RESULTS: For the final model, the oral clearance (CL/F) of LTG was estimated to be 0.705 L/h with inter-individual variability (IIV) of 21.3%. The estimates generated by NONMEM indicated that the LTG CL/F was significantly influenced by patient body weight (increased with an exponent of 0.574) and VPA concentration (decreased with linearity of 0.273 with co-administration). However, no significant effects of UGT1A4 or UGT2B7 polymorphisms on LTG CL/F were noted in this population of Chinese children. CONCLUSION: This study confirms the interaction of LTG with VPA, which likely depends on VPA concentration. The LTG PPK model developed in this study could be useful for individualizing LTG dosage regimens in pediatric patients receiving combination therapy, especially therapy that includes VPA.

Development of a Simple and Rapid Method to Measure Free Fraction of Valproic Acid in Plasma Using Ultrafiltration and Ultra High Performance Liquid Chromatography-Mass Spectroscopy: Application to Therapeutic Drug Monitoring.

BACKGROUND: Valproic acid (VPA) is widely used as an antiepileptic drug in children, and it is usually coadministered with other antiepileptic drugs. Because of its narrow therapeutic range and large variations in pharmacokinetic/pharmacodynamic behavior in different individuals, therapeutic drug monitoring of the trough total VPA concentration is commonly used to guide dosing. However, as only the free fraction of VPA that exerts pharmacological and toxic effects, it may be more meaningful to determine the unbound VPA concentration in plasma. METHODS: Free fraction of VPA in plasma was extracted by ultrafiltration. Ultra high performance liquid chromatography coupled with mass spectroscopy was used to measure VPA in the negative ionization mode. This method was validated by studies of its selectivity, linearity, lower limit of quantification, accuracy, precision, recovery, matrix effect, and stability. RESULTS: The method was validated over a linear range of 0.2-25 mcg/mL, and its lower limit of quantification was 0.2 mcg/mL. The method's relative standard deviations for intra- and inter-day precision were <15%, and its accuracy (relative error) was ±3.22%. The recoveries and matrix effect of unbound VPA at 3 different concentrations satisfied our requirements for the analysis of biological samples, and no significant degradation of VPA was observed under different storage conditions. CONCLUSIONS: Simple ultra high performance liquid chromatography coupled with mass spectroscopy showed good performance when used to measure unbound VPA concentration, this method may be used to study the relationship between unbound VPA concentrations and its effectiveness by the use of therapeutic drug monitoring.

Effects of Polymorphisms in NR1H4, NR1I2, SLCO1B1, and ABCG2 on the Pharmacokinetics of Rosuvastatin in Healthy Chinese Volunteers.

The nuclear receptors (NR)-farnesoid X receptor (FXR, NR1H4) and pregnane X receptor (PXR, NR1I2)-have important effects on the expression of genes related to the pharmacokinetics (PKs) of rosuvastatin. This study was designed to investigate whether the genetic variants in drug disposition genes (SLCO1B1 and ABCG2) combined with their upstream regulators (NR1H4 and NR1I2) would affect the PKs of rosuvastatin in a Chinese population. Sixty-one healthy male volunteers were enrolled and the plasma concentrations of rosuvastatin were measured using the liquid chromatographic-tandem mass spectrometry/MS method. All subjects were analyzed and grouped according to the genotypes of NR1H4, NR1I2, SLCO1B1, and ABCG2. The exposure of rosuvastatin was higher in subjects carrying the SLCO1B1 521C or ABCG2 421A allele compared with noncarriers. No association was observed of single-nucleotide polymorphisms in NR1H4 or NR1I2 genes with the PKs of rosuvastatin. After adjusting for the 421C>A and 521T>C variants, the Cmax in subjects with NR1I2 63396TT wild type were about 2-fold of those of NR1I2 mutant type (63396CC and CT) (10.7 vs. 20.4 ng/mL, P = 0.023), whereas no significant differences were observed for other parameters. Polymorphisms investigated in the genes of NR1H4 and NR1I2 seemed to play no significant role in the disposition of rosuvastatin.

Model Informed Development of SIM0295 in Patients with Gout and Hyperuricemia and Healthy Volunteers Using a Population Pharmacokinetics/ Pharmacodynamics Approach.

BACKGROUND: SIM0295, a novel inhibitor of human uric acid transporter 1 (hURAT1), is used to treat patients with gout and hyperuricemia. This study aimed to develop population pharmacokinetics and pharmacodynamics (popPK/PD) models of SIM0295 and explore potential covariates to inform clinical drug development. RESEARCH DESIGN AND METHODS: Data were obtained from four phase I studies conducted in healthy Korean and Chinese subjects and two phase II studies conducted in Korean patients with gout and hyperuricemia. The popPK/PD model of SIM0295 was developed using nonlinear mixed effects modeling. RESULTS: SIM0295 pharmacokinetics was described using a two-compartment model with the absorption of four transit compartments and first-order elimination. PK parameters were normalized to weight via allometric scaling. Food was identified as a factor significantly affecting the absorption rate, with no clinical relevance. The sigmoid Emax model with a semi-mechanism of inhibition of serum uric acid (sUA) reabsorption was used to describe the exposure-response relationship. Additionally, Monte Carlo simulations demonstrated that approimately 9 mg/day of SIM0295 for 7 days could achieve the maximum decrease in sUA. CONCLUSION: The established popPK/PD model characterized the dose-exposure-response relationship for SIM0295 in healthy subjects and patients with gout and hyperuricemia and could be used to inform the drug development.

Lipidomic Profiling Reveals Disruption of Lipid Metabolism in Valproic Acid-Induced Hepatotoxicity.

Valproic acid (VPA) is one of the most widely prescribed antiepileptic drugs, as VPA-induced hepatotoxicity is one of the most severe adverse reaction that can lead to death. The objective of this study was to gain an understanding of dysregulated lipid metabolism in mechanism of hepatotoxicity. Nontargeted lipidomics analysis with liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF/MS) was performed to explore differential lipids from the patient serum and L02 cells. Lipidomics data interpretation was augmented by gene expression analyses for the key enzymes in lipid metabolism pathways. From patient serum lipidomics, pronouncedly changed lipid species between abnormal liver function (ALF) patients and normal liver function (NLF) patients were identified. Among these lipid species, LPCs, Cers, and SMs were markedly reduced in the ALF group and showed negative relationships with liver injury severity [alanine aminotransferase (ALT) levels], while significantly increased triacylglycerols (TAG) with higher summed carbon numbers demonstrated a positive relationship with ALT levels. Regarding lipidomics in hepatic L02 cells, TAG was markedly elevated after VPA exposure, especially in TAGs with more than 53 summed carbons. Besides, gene expression analysis revealed dysregulated lipid metabolism in VPA-treated L02 cells. Peroxime proliferators-activated receptor (PPARγ) pathway played an important role in VPA-induced lipid disruption through inducing long-chain fatty acid uptake and TAG synthesis, which was also regulated by Akt pathway. Our findings present that VPA-induced lipid metabolism disruption might lead to lipotoxicity in the liver. This approach is expected to be applicable for other drug-induced toxicity assessments.

Association between the perturbation of bile acid homeostasis and valproic acid-induced hepatotoxicity.

Valproic acid (VPA), a widely prescribed antiepileptic drug, is known to induce hepatotoxicity. However, the mechanisms underlying this toxicity are not well understood. In this study, we performed a nontargeted metabolomic analysis of children with epilepsy treated with VPA (n = 23). Metabolic pathway analysis showed that the fatty acid pathway, citrate cycle, urea cycle, amino acid metabolism, and bile acid pathway were altered in children with epilepsy exhibiting VPA hepatotoxicity. In particular, the VPA-induced perturbation of bile acid homeostasis has not been observed previously. Based on these findings, we performed a targeted metabolomic analysis to characterize bile acid profiles and further determined the effects of VPA on the synthesis, transport, and regulation of bile acids in mice. The bile acid metabolomic profiles of the livers of mice treated with VPA indicated an increase in most bile acids, especially chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA), as well as unconjugated bile acids. The upregulation of genes related to bile acid synthesis (CYP7A1 and CYP8B1) and the downregulation of genes related to conjugation (BAAT and BACS) and regulation (FXR and SHP) were detected in the liver, suggesting that hydrophobic bile acid production was increased and FXR signaling was impaired. Our results suggest that the perturbation of bile acid homeostasis and impaired FXR signaling are involved in VPA-induced hepatotoxicity, providing a novel insight into VPA hepatotoxicity.

Population pharmacokinetics of valproic acid in epileptic children: Effects of clinical and genetic factors.

Valproic acid (VPA) is a first-line anti-epileptic drug that is used in the treatment of generalized and partial seizures. Gene variants had been proved to influence the pharmacokinetics (PK) of VPA and contribute to its inter-individual variability (IIV). The aim of this study was to systematically investigate the effects of candidate gene variants (CYPs, UGTs, ABC transporters, and nuclear receptors) on VPA PK in Chinese children with epilepsy. A total of 1065 VPA serum trough concentrations at steady state were collected from 264 epileptic pediatric patients aged 3 months to 16 years. The population pharmacokinetic (PPK) model was developed using a nonlinear mixed effects modelling (NONMEM) approach. For the final PPK model, the oral clearance (CL/F) of VPA was estimated to be 0.259 L/h with IIV of 13.3%. The estimates generated by NONMEM indicated that the VPA CL/F was significantly influenced by patient body weight (increased by an exponent of 0.662), co-administration with carbamazepine (increased CL/F by 22%), and daily dose of VPA (increased by an exponent of 0.22). CL/F in patients with the LEPR rs1137101 variant (668 AG and GG genotypes) was much lower than in patients with the AA genotype (17.8% and 22.6% lower, respectively). However, none of the CYPs or UGTs gene variants was found to influence the PK of VPA in this study. Evaluation by bootstrap and normalized prediction distribution error (NPDE) showed that the final model was stable. The predictive performance was evaluated by goodness-of-fit (GOF) plots and visual predictive checks (VPC), and the results indicated satisfactory precision. Our model suggests a correlation between VPA CL/F and LEPR rs1137101 variants, which might be beneficial in the context of individual dose optimization.