A genetic-based population PK/PD modeling of methadone in Chinese opiate dependence patients.

PURPOSE: The full potential of methadone maintenance treatment (MMT) is often limited by the large inter-individual variability in both pharmacokinetics (PK) and pharmacodynamics (PD), and by the risk of torsade de pointes, a severe adverse effect caused by QTc prolongation. The current study aims to quantitate the contribution of genetic polymorphisms and other variables in PK/PD variability, and their contribution to the QTc interval prolongation in Chinese MMT patients. METHODS: Population PK models were developed to fit (R)- and (S)-methadone PK data. Hierarchical models were tested to characterize the PK profile, the concentration-QTc relationship, and concentration-urinalysis illicit drug testing relationship, with demographics and genetic variants being included as covariates. Simulation based on the developed PK/PD models was performed to assess the effect of methadone dose and genetic variants on QTc interval prolongation. RESULTS: The PK data were best-fit by a one-compartment, first-order absorption model. Clearance of (R)- and (S)-methadone was both affected by the weighted activity score derived from genetic variants. A linear model was used to describe both the methadone concentration-urinalysis illicit drug testing relationship and the methadone concentration-QTc relationship. Concentration of (R)- and (S)-methadone exhibits a comparable effect on QTc prolongation. Simulation showed that the percentage of QTc higher than 450 ms was almost doubled in the lowest clearance group as compared the highest when methadone dose was greater than 120 mg. CONCLUSIONS: The large variability in PK/PD profiles can be partially explained by the genetic variants in an extent different from other population, which confirmed the necessity to conduct such a study in the specific Chinese patients.

MicroRNA-184 acts as a potential diagnostic and prognostic marker in epithelial ovarian cancer and regulates cell proliferation, apoptosis and inflammation.

MicroRNA-184 (miR-184) is found to be significantly deregulated in human cancers associated with tumorigenesis and progression. In this study, we aimed to investigate the role and mechanism of miR-184 expression in epithelial ovarian cancer (EOC). Relative expression of miR-184 was measured by quantificational real-time polymerase chain reaction assay (qRT-PCR) in 80 EOC patients. Kaplan-Meier curve and the log-rank test were conducted to detect the prognostic value of miR-184. Function assays including cell proliferation, apoptosis and inflammation were further explored in vitro. We found that miR-184 was down-regulated in EOC tissues and cell lines compared with paired non-cancerous tissues and IOSE, respectively. Moreover, miR-184 was expressed at significantly lower levels in late-stage (III/IV) EOC tissues. Cox regression multivariate analysis indicated that miR-184 and FIGO stage were independent prognostic indicators for EOC patients. Patients with high miR-184 level achieved significantly a higher 5-year survival rate compared with low level group (P < 0.001). Functional assays showed that miR-184 over-expression could suppress EOC cell proliferation as well as inflammation and induce apoptosis in vitro. Altogether, our results suggest that miR-184 together with pathologic diagnosis is critical for prognosis determination in EOC patients and help select treatment strategy.

Analysis of Niemann-Pick C1-like 1 (NPC1L1) genetic polymorphisms and haplotypes in Chinese Han population.

Niemann-Pick C1-like 1 (NPC1L1i) protein is the key transporter responsible for dietary cholesterol absorption. Recent studies indicated that several functional polymorphisms of NPC1L1 were associated with coronary heart disease (CHD) and response to ezetimibe therapy. The aim of the present study was to analyze the allele frequency and haplotype distribution of NPC1L1 polymorphisms in Chinese Hans and to compare them with those of other ethnic populations reported before. Blood samples were collected from 424 unrelated Chinese Hans (246 males and 178 females). Ten NPC1L1 polymorphisms (-762T > C, -133A > G, -18C > A, 1721C > T, 1735C > G, 1764T > C, 1767G > A, 27677T > C, 25342A > C and 28650A > G) were genotyped by direct sequencing or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Among the variants, the minor allele frequency of -762T > C and 1735C > G were 35.0% and 37.0%, respectively. Furthermore, these two polymorphisms were highly linked with a D' value of 0.80. The observed frequencies of two major haplotypes were 59.1% for T-762/C1735 and 30.1% for C-762/G1735, respectively. The frequencies of the rest variants were extremely low (1.8% for - 133G, 1.5% for -18A, 0.9% for 1721T and only 0.2% for 27677C allele, respectively) or even not detected (1764T > C, 1767G > A, 25342A > C and 28650A > G) in our study population. Comparison with other ethnic populations revealed a remarkable genetic variability in the incidences of NPC1L1 polymorphisms. The frequencies of NPC1L1 polymorphisms in Chinese Hans are comparable to Japanese population but totally different from Caucasians, African-Americans and Hispanic individuals. This is the first study to report the ethnic difference in the frequencies of NPC1L1 functional polymorphisms in detail. -762T > C and 1735C > G are two prevalent NPC1L1 variants which need further studies to explore their clinical impact on CHD prevalence and response to ezetimibe therapy in Chinese Hans.

Puerarin protects endothelial cells from oxidized low density lipoprotein induced injuries via the suppression of LOX-1 and induction of eNOS.

Oxidized low density lipoprotein (oxLDL) induced injury of endothelial cells is considered to be the first step in the pathogenesis of atherosclerosis. This study aimed to investigate some of the effects and mechanisms of puerarin on oxLDL-induced endothelial injuries. We measured cell viability, and the release of lactate dehydrogenase (LDH), nitric oxide (NO), and interleukin-8 (IL-8) to evaluate the protective effects of puerarin. Intracellular reactive oxygen species (ROS) were detected using 2',7'-dichlorofluorescein diacetate (DCFH-DA). The expression of lectin-like low-density lipoprotein receptor-1 (LOX-1), endothelial nitric oxide synthase (eNOS), cyclooxygenase 2 (COX-2), p38MAPK, and protein kinase B (PKB) phosphorylation, nuclear factor-κB (NF-κB) nuclear translocation, and inhibitor of κB (IκB) degradation were detected using quantitative real-time PCR or Western blot. The results showed that oxLDL significantly decreased cell viability, increased LDH and IL-8 release, inhibited NO production, and induced COX-2 expression. Pretreatment with puerarin led to a strong inhibition of these effects. OxLDL stimulated the expression of LOX-1, the overproduction of ROS, the phosphorylation of p38MAPK, the dephosphorylation of PKB, activation of NF-κB, and the degradation of IκB. These oxLDL-induced effects were suppressed after puerarin pretreatment. These results suggest that puerarin inhibits oxLDL-induced endothelial cell injuries, at least in part, via inhibition of the LOX-1-mediated p38MAPK-NF-κB inflammatory and the PKB-eNOS signaling pathways.

The effect of Na+/taurocholate cotransporting polypeptide (NTCP) c.800C > T polymorphism on rosuvastatin pharmacokinetics in Chinese healthy males.

This study was designed to investigate the potential association between NTCP c.800C >T polymorphism and rosuvastatin pharmacokinetics in Chinese healthy males. 305 individuals were enrolled to identify NTCP c.800C > T, OATP1B1 c.521T > C and BCRP c.421C > A genotypes by direct sequencing and pyrosequencing methods, respectively. 17 healthy volunteers who were OATP1B1 c.521TT and BCRP c.421CC wild-type homozygotes with different NTCP c.800C > T genotype were selected to participate in this pharmacokinetic study. Nine were NTCP c.800CC wild-type homozygotes and the other eight subjects were carriers with at least one c.800T variant allele (seven subjects with c.800CT genotype and one was homozygote of c.800TT). All the subjects received a single oral dose of 10 mg rosuvastatin. The plasma concentrations of rosuvastatin were measured up to 72 h by a LC-MS method. NTCP c.800C > T genetic polymorphism markedly effected rosuvastatin pharmacokinetics. The AUC(o-72) and AUC(0 --> ∞) in subjects with NTCP c.800CT + TT genotype were 56% (162.64 ± 37.55 vs. 103.99 ± 28.15 ng x h/ml, P = 0.016) and 57% greater (178.51 ± 42.75 vs. 113.60 ± 33.73 ng x h/ml, P = 0.020) than those in the c.800CC wild-type subjects, respectively. In the c.800CT + TT mutant group, the C(max) was about 78% higher than those in c.800CC genotype (14.31 ± 3.63 vs. 8.04 ± 1.72 ng x h/ml, P = 0.004). The oral clearance (CL/F) of rosuvastatin in subjects with the c.800CT+TT genotype was only 63% of those in the c.800CC genotype (58.32 ± 12.16 vs. 93.04 ± 20.61 ng x h/ml, P = 0.009). The half-time (T1/2) and the T(max) had no significant difference between two groups (p = 0.466 and 0.713, respectively). NTCP c.800C > T polymorphism play a critical role in the individual variability of rosuvastatin pharmacokinetics in Chinese healthy males after excluding the impact of OATP1B1 c.521T > C and BCRP c.421C > A polymorphisms.

Is circulating tumor cell count-driven cost-effective for first-line therapy choice in HR+/HER2- metastatic breast cancer in the United States?

BACKGROUND: Circulating tumor cell (CTC) counting may be a useful non-invasive biomarker that helps patients choose first-line treatment options. Nevertheless, the cost of CTC inspection may impose an economic burden on patients, necessitating the simultaneous consideration of both its clinical effectiveness and cost. We evaluated the cost-effectiveness of CTC count-guided chemotherapy and endocrine therapy as first-line therapy for HR+/HER2-metastatic breast cancer (MBC) from the perspective of US payers. METHODS: Based on the STIC CTC trial, a Markov model was constructed for three health states, and health outcomes were measured in quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were performed to assess the robustness of the incremental cost per QALY. RESULTS: The base-case analysis revealed that CTC count-driven treatment was associated with improved effectiveness by 0.07 QALYs and increased the overall cost by $9187.05 compared with clinician-driven first-line treatment choices, leading to an ICER of $138 354.15 per QALY. One-way sensitivity analysis indicated that the model was most sensitive to the cost of treatment for neutropenia and the utility for PFS; probability sensitivity analysis indicated that CTC count-driven treatment choices would be considered the cost-effective option at a willingness-to-pay threshold of $150 000 per QALY. CONCLUSIONS: The findings of this cost-effectiveness analysis suggest that, at the current price of CTC enumeration, choosing first-line treatment options based on CTC count is a cost-effectiveness approach for treating patients with HR+/HER2- MBC in the US.

Let-7 in cardiovascular diseases, heart development and cardiovascular differentiation from stem cells.

The let-7 family is the second microRNA found in C. elegans. Recent researches have found it is highly expressed in the cardiovascular system. Studies have revealed the aberrant expression of let-7 members in cardiovascular diseases, such as heart hypertrophy, cardiac fibrosis, dilated cardiomyopathy (DCM), myocardial infarction (MI), arrhythmia, angiogenesis, atherosclerosis, and hypertension. Let-7 also participates in cardiovascular differentiation of embryonic stem cells. TLR4, LOX-1, Bcl-xl and AGO1 are by now the identified target genes of let-7. The circulating let-7b is suspected to be the biomarker of acute MI and let-7i, the biomarker of DCM. Further studies are necessary for identifying the gene targets and signaling pathways of let-7 in cardiovascular diseases. Let-7 might be a potential therapeutic target for cardiovascular diseases. This review focuses on the research progresses regarding the roles of let-7 in cardiovascular development and diseases.

Up-Regulation of CYP2C19 Expression by BuChang NaoXinTong via PXR Activation in HepG2 Cells.

BACKGROUND: Cytochrome P450 2C19 (CYP2C19) is an important drug-metabolizing enzyme (DME), which is responsible for the biotransformation of several kinds of drugs such as proton pump inhibitors, platelet aggregation inhibitors and antidepressants. Previous studies showed that Buchang NaoXinTong capsules (NXT) increased the CYP2C19 metabolic activity in vitro and enhanced the antiplatelet effect of clopidogrel in vivo. However, the underlying molecular mechanism remained unclear. In the present study, we examined whether Pregnane X receptor (PXR) plays a role in NXT-mediated regulation of CYP2C19 expression. METHODS: We applied luciferase assays, real-time quantitative PCR (qPCR), Western blotting and cell-based analysis of metabolic activity experiments to investigate the NXT regulatory effects on the CYP2C19 promoter activity, the mRNA/ protein expression and the metabolic activity. RESULTS: Our results demonstrated that NXT significantly increased the CYP2C19 promoter activity when co-transfected with PXR in HepG2 cells. Mutations in PXR responsive element abolished the NXT inductive effects on the CYP2C19 promoter transcription. Additionally, NXT incubation (150 and 250µg/mL) also markedly up-regulated endogenous CYP2C19 mRNA and protein levels in PXR-transfected HepG2 cells. Correspondingly, NXT leaded to a significant enhancement of the CYP2C19 catalytic activity in PXR-transfected HepG2 cells. CONCLUSION: In summary, this is the first study to suggest that NXT could induce CYP2C19 expression via PXR activation.

URAT1 gene polymorphisms influence uricosuric action of losartan in hypertensive patients with hyperuricemia.

AIMS: To explore the effect of urate transporter 1 (URAT1) polymorphisms on the hypertensive patients with hyperuricemia and the uricosuric action of losartan therapy among hypertensive patients with hyperuricemia. METHODS: 101 hypertensive patients with hyperuricemia were detected the genotypes of URAT1 rs1529909 and rs3825016 and undergo a 2-weeks following losartan treatment. Before and after treatment, serum uric acid (SUA) and other clinical data were compared between different genotypes of URAT1 patients. RESULTS: The frequency of rs3825016 (C/T) CT genotype was significant higher in the hypertensive patients with hyperuricemia than that in the healthy controls (32.7 vs 18.8%; p = 0.02). After lorsatan treatment, the patients with the rs3825016 (C/T) or rs1529909 (T/C) mutant genotypes had lower decreased value (DV) of SUA compared with the patients who are wild-type of the variant (p = 0.001 and p < 0.001, respectively). Combined the two variants together, the DV of SUA in two variants both wild-type patients higher than that in the two variants mutant patients (p < 0.0001). CONCLUSION: These results suggest that URAT1 rs3825016 and rs1529909 polymorphisms influence the uricosuric action of losartan. Original submitted 20 August 2014; Revision submitted 15 April 2015.

Protective effects of let-7a and let-7b on oxidized low-density lipoprotein induced endothelial cell injuries.

Lectin-like low-density lipoprotein receptor 1 (LOX-1) is a receptor for oxidized low density lipoprotein (oxLDL) in endothelial cells. The activation of LOX-1 by oxLDL stimulates the apoptosis and dysfunction of endothelial cells, and contributes to atherogenesis. However, the regulatory factors for LOX-1 are still unclear. MicroRNAs are small, endogenous, non-coding RNAs that regulate gene expressions at a post-transcriptional level. The let-7 family is the second microRNA been discovered, which plays important roles in cardiovascular diseases. Let-7a and let-7b were predicted to target LOX-1 3'-UTR and be highly expressed in endothelial cells. The present study demonstrated that LOX-1 was a target of let-7a and let-7b. They inhibited the expression of LOX-1 by targeting the positions of 310-316 in LOX-1 3'-UTR. Over-expression of let-7a and let-7b inhibited the oxLDL-induced endothelial cell apoptosis, NO deficiency, ROS over-production, LOX-1 upregulation and endothelial nitric oxide synthase (eNOS) downregulation. Moreover, we found that oxLDL treatment induced p38MAPK phosphorylation, NF-κB nuclear translocation, IκB degradation and PKB dephosphorylation. Let-7a or let-7b over-expression attenuated these alterations significantly. The present study may provide a new insight into the protective properties of let-7a and let-7b in preventing the endothelial dysfunction associated with cardiovascular disease, such as atherosclerosis.

Let-7c inhibits NSCLC cell proliferation by targeting HOXA1.

OBJECTIVE: The aim of the present study was to explore mechanisms by which let-7c suppresses NSCLC cell proliferation. METHODS: The expression level of let-7c was quantified by qRT-PCR. A549 and H1299 cells were transfected with let-7c mimics to restore the expression of let-7c. The effects of let-7c were then assessed by cell proliferation, colony formation and cell cycle assay. Mouse experiments were used to confirm the effect of let-7c on tumorigenicity in vivo. Luciferase reporter assays and Western blotting were performed to identify target genes for let-7c. RESULTS: HOXA1 was identified as a novel target of let-7c. MTS, colony formation and flow cytometry assays demonstrated that forced expression of let-7c inhibited NSCLC cell proliferation by inducing G1 arrest in vitro, consistent with inhibitory effects induced by knockdown of HOXA1. Mouse experiments demonstrated that let-7c expression suppressed tumorigenesis. Furthermore, we found that let-7c could regulate the expression of HOXA1 downstream effectors CCND1, CDC25A and CDK2. CONCLUSIONS: Collectively, these results demonstrate let-7c inhibits NSCLC cell proliferation and tumorigenesis by partial direct targeting of the HOXA1 pathway, which suggests that restoration of let-7c expression may thus offer a potential therapeutic intervention strategy for NSCLC.

Different involvement of promoter methylation in the expression of organic cation/carnitine transporter 2 (OCTN2) in cancer cell lines.

Organic cation/carnitine transporter 2 (OCTN2) is responsible for the cellular uptake of the antineoplastic agent, oxaliplatin. Epigenetic modification is a possible mechanism of altered drug-transporter expression in cancers, leading to altered efficacy of chemotherapeutic drugs. However, the mechanisms governing OCTN2 regulation are not completely understood. In this study, the low levels of OCTN2 in HepG2 and LS174T cells were elevated by the demethylating reagent, decitabine (DCA). To further reveal the epigenetic mechanism of down-regulation of OCTN2, we found that Region-1 within the OCTN2 promoter (spanning -354 to +85) was a determinant of OCTN2 expression in a luciferase reporter assay. Moreover, methylation-specific PCR (MSP) and bisulfite genomic sequencing showed that the degree of individual methylated CpG sites within this region was inversely correlated with the levels of OCTN2 in different cancer cells. Application of DCA to HepG2 and LS174T cells reversed the hypermethylation status of the OCTN2 promoter and increased OCTN2 expression, enhancing cellular uptake of oxaliplatin. Thus, we identified that promoter methylation is responsible for epigenetic down-regulation of OCTN2 in HepG2 and LS174T cells. Given the essential role of OCTN2 in cancer cell uptake of chemotherapeutics, and thus treatment efficacy, pretreatment with a demethylating reagent is a possible strategy for optimizing pharmacotherapies against cancers.