It has been reported that the miR-106b∼25 cluster, a paralog of the miR-17∼92 cluster, possesses oncogenic activities. However, the precise role of each microRNA (miRNA) in the miR-106b∼25 cluster is ...not yet known. In this study, we examined the function of miR-93, one of the microRNAs within the miR-106b∼25 cluster, in angiogenesis and tumor formation. We found that miR-93 enhanced cell survival, promoted sphere formation and augmented tumor growth. Most strikingly, when miR-93-overexpressing U87 cells were co-cultured with endothelial cells, they supported endothelial cell spreading, growth, migration and tube formation. In vivo studies revealed that miR-93-expressing cells induced blood vessel formation, allowing blood vessels to extend to tumor tissues in high densities. Angiogenesis promoted by miR-93 in return facilitated cell survival, resulting in enhanced tumor growth. We further showed that integrin-β8 is a target of miR-93. Higher levels of integrin-β8 are associated with cell death in tumor mass and in human glioblastoma. Silencing of integrin-β8 expression using small interfering RNA promoted cell proliferation, whereas ectopic expression of integrin-β8 decreased cell growth. These findings showed that miR-93 promotes tumor growth and angiogenesis by suppressing, at least in part, integrin-β8 expression. Our results suggest that inhibition of miR-93 function may be a feasible approach to suppress angiogenesis and tumor growth.
Thiopurine methyltransferase (TPMT) activity exhibits monogenic co‐dominant inheritance, with ethnic differences in the frequency of occurrence of variant alleles. With conventional thiopurine doses, ...homozygous TPMT‐deficient patients (~1 in 178 to 1 in 3,736 individuals with two nonfunctional TPMT alleles) experience severe myelosuppression, 30–60% of individuals who are heterozygotes (~3–14% of the population) show moderate toxicity, and homozygous wild‐type individuals (~86–97% of the population) show lower active thioguanine nucleolides and less myelosuppression. We provide dosing recommendations (updates at http://www.pharmgkb.org) for azathioprine, mercaptopurine (MP), and thioguanine based on TPMT genotype.
Clinical Pharmacology & Therapeutics (2011) 89 3, 387–391. doi:10.1038/clpt.2010.320
The Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for Thiopurine Methyltransferase Genotype and Thiopurine Dosing was originally published in March 2011. We reviewed recent ...literature and concluded that although relevant new evidence has been generated, none of the evidence would change the primary dosing recommendations in the original guideline; therefore, the original publication remains clinically current. Up‐to‐date information on thiopurine methyltransferase (TPMT) gene alleles and nomenclature can be found at PharmGKB (http://www.pharmgkb.org).
Clinical Pharmacology & Therapeutics (2013); 93 4, 324–325. doi:10.1038/clpt.2013.4
Transporter‐mediated drug‐drug interactions (DDIs) are a major cause of drug toxicities. Using published genome‐wide association studies (GWAS) of the human metabolome, we identified 20 metabolites ...associated with genetic variants in organic anion transporter, OATP1B1 (P < 5 × 10−8). Of these, 12 metabolites were significantly higher in plasma samples from volunteers dosed with the OATP1B1 inhibitor, cyclosporine (CSA) vs. placebo (q‐value < 0.2). Conjugated bile acids and fatty acid dicarboxylates were among the metabolites discovered using both GWAS and CSA administration. In vitro studies confirmed tetradecanedioate (TDA) and hexadecanedioate (HDA) were novel substrates of OATP1B1 as well as OAT1 and OAT3. This study highlights the use of multiple datasets for the discovery of endogenous metabolites that represent potential in vivo biomarkers for transporter‐mediated DDIs. Future studies are needed to determine whether these metabolites can serve as qualified biomarkers for organic anion transporters. Quantitative relationships between metabolite levels and modulation of transporters should be established.
Background
The rates of hepatitis B surface antigen (HBsAg) seroclearance after stopping nucleos(t)ide analogues (NA) in European (19% in 2 years) and Asian (13% in 6 years) patients with chronic ...hepatitis B (CHB) vary dramatically. We evaluated the incidence of hepatitis flare and HBsAg seroclearance in hepatitis B e antigen (HBeAg)‐negative Chinese CHB patients who had stopped NA.
Methods
This was a territory‐wide retrospective study in Hong Kong. We identified HBeAg‐negative CHB patients from January 2000 to December 2017 who had stopped NA treatment for more than 3 months. Hepatitis flare was defined as ALT >2×ULN.
Results
The 1076 patients were predominantly middle‐aged men (mean age 52 years, male 74.8%) when starting NA; they stopped NA after 82 ± 35 months of treatment. At 44.3 ± 24.6 months after stopping NA, 147 (13.6%) patients had hepatitis flare, which led to resumption of NA; whereas 77 (7.2%) patients had flare but did not resume NA. Decompensation occurred in 7/914 (0.8%) patients. A total of 695 (64.6%) patients remained on NA treatment at the last visit. Eleven patients had achieved HBsAg seroclearance (6 of them had hepatitis flare and 1 of these 6 patients achieved HBsAg seroclearance after NA was restarted). Hepatic events developed in 75/695 (10.8%) patients who had NA resumed vs 43/381 (11.3%) patients who did not resume NA (P = .677).
Conclusions
Hepatitis flare and retreatment were common in HBeAg‐negative CHB patients who stopped NA treatment; whereas HBsAg seroclearance rarely occurred. Stopping NA to achieve functional cure should not be recommended at this moment.
The first‐line treatment of hyperuricemia, which causes gout, is allopurinol. The allopurinol response is highly variable, with many users failing to achieve target serum uric acid (SUA) levels. No ...genome‐wide association study (GWAS) has examined the genetic factors affecting allopurinol effectiveness. Using 2,027 subjects in Kaiser Permanente's Genetic Epidemiology Research on Adult Health and Aging (GERA) Cohort, we conducted a GWAS of allopurinol‐related SUA reduction, first in the largest ethnic group, non‐Hispanic white (NHW) subjects, and then in a stratified transethnic meta‐analysis. ABCG2, encoding the efflux pump BCRP, was associated with SUA reduction in NHW subjects (P = 2 × 10−8), and a missense allele (rs2231142) was associated with a reduced response (P = 3 × 10−7) in the meta‐analysis. Isotopic uptake studies in cells demonstrated that BCRP transports allopurinol and genetic variants in ABCG2 affect this transport. Collectively, this first GWAS of allopurinol response demonstrates that ABCG2 is a key determinant of response to the drug.
Interindividual variation in response to metformin, first‐line therapy for type 2 diabetes, is substantial. Given that transporters are determinants of metformin pharmacokinetics, we examined the ...effects of promoter variants in both multidrug and toxin extrusion protein 1 (MATE1) (g.–66T→C, rs2252281) and MATE2 (g.–130G→A, rs12943590) on variation in metformin disposition and response. The pharmacokinetics and glucose‐lowering effects of metformin were assessed in healthy volunteers (n = 57) receiving metformin. The renal and secretory clearances of metformin were higher (22% and 26%, respectively) in carriers of variant MATE2 who were also MATE1 reference (P < 0.05). Both MATE genotypes were associated with altered post‐metformin glucose tolerance, with variant carriers of MATE1 and MATE2 having an enhanced (P < 0.01) and reduced (P < 0.05) response, respectively. Consistent with these results, patients with diabetes (n = 145) carrying the MATE1 variant showed enhanced metformin response. These findings suggest that promoter variants of MATE1 and MATE2 are important determinants of metformin disposition and response in healthy volunteers and diabetic patients.
Clinical Pharmacology & Therapeutics (2013); 93 2, 186–194. doi:10.1038/clpt.2012.210
The neuroprotective function of the blood–brain barrier (BBB) presents a major challenge for drug delivery to the central nervous system (CNS). Critical to this function, BBB membrane transporters ...include the ATP‐binding cassette (ABC) transporters, which limit drug penetration across the BBB, and the less‐well‐studied solute carrier (SLC) transporters. In this work, expression profiling of 359 SLC transporters, comparative expression analysis with kidney and liver, and immunoassays in brain microvessels (BMVs) identified previously unknown transporters at the human BBB.
Clinical Pharmacology & Therapeutics (2013); 94 6, 636–639. doi:10.1038/clpt.2013.175
Background
Vitamins and minerals play multiple functions within the central nervous system which may help to maintain brain health and optimal cognitive functioning. Supplementation of the diet with ...various vitamins and minerals has been suggested as a means of maintaining cognitive function, or even of preventing dementia, in later life.
Objectives
To evaluate the effects of vitamin and mineral supplementation on cognitive function in cognitively healthy people aged 40 years or more.
Search methods
We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group’s (CDCIG) specialised register, as well as MEDLINE, Embase, PsycINFO, CINAHL, ClinicalTrials.gov and the WHO Portal/ICTRP from inception to 26th January 2018.
Selection criteria
We included randomised controlled trials that evaluated the cognitive effects on people aged 40 years or more of any vitamin or mineral supplements taken by mouth for at least three months.
Data collection and analysis
Study selection, data extraction, and quality assessments were done in duplicate. Vitamins were considered broadly in the categories of B vitamins, antioxidant vitamins, and combinations of both. Minerals were considered separately, where possible. If interventions and outcomes were considered sufficiently similar, then data were pooled. In order to separate short‐term cognitive effects from possible longer‐term effects on the trajectory of cognitive decline, data were pooled for various treatment durations from 3 months to 12 months and up to 10 years or more.
Main results
In total, we included 28 studies with more than 83,000 participants. There were some general limitations of the evidence. Most participants were enrolled in studies which were not designed primarily to assess cognition. These studies often had no baseline cognitive assessment and used only brief cognitive assessments at follow‐up. Very few studies assessed the incidence of dementia. Most study reports did not mention adverse events or made only very general statements about them. Only 10 studies had a mean follow‐up > 5 years. Only two studies had participants whose mean age was < 60 years at baseline. The risk of bias in the included studies was generally low, other than a risk of attrition bias for longer‐term outcomes. We considered the certainty of the evidence behind almost all results to be moderate or low.
We included 14 studies with 27,882 participants which compared folic acid, vitamin B12, vitamin B6, or a combination of these to placebo. The majority of participants were aged over 60 years and had a history of cardio‐ or cerebrovascular disease. We found that giving B vitamin supplements to cognitively healthy adults, mainly in their 60s and 70s, probably has little or no effect on global cognitive function at any time point up to 5 years (SMD values from ‐0.03 to 0.06) and may also have no effect at 5‐10 years (SMD ‐0.01). There were very sparse data on adverse effects or on incidence of cognitive impairment or dementia.
We included 8 studies with 47,840 participants in which the active intervention was one or more of the antioxidant vitamins: ß‐carotene, vitamin C or vitamin E. Results were mixed. For overall cognitive function, there was low‐certainty evidence of benefit associated with ß‐carotene after a mean of 18 years of treatment (MD 0.18 TICS points, 95% CI 0.01 to 0.35) and of vitamin C after 5 years to 10 years (MD 0.46 TICS points, 95% CI 0.14 to 0.78), but not at earlier time points. From two studies which reported on dementia incidence, there was low‐certainty evidence of no effect of an antioxidant vitamin combination or of vitamin E, either alone or combined with selenium. One of the included studies had been designed to look for effects on the incidence of prostate cancer; it found a statistically significant increase in prostate cancer diagnoses among men taking vitamin E.
One trial with 4143 participants compared vitamin D3 (400 IU/day) and calcium supplements to placebo. We found low‐ to moderate‐certainty evidence of no effect of vitamin D3 and calcium supplements at any time‐point up to 10 years on overall cognitive function (MD after a mean of 7.8 years ‐0.1 MMSE points, 95% CI ‐0.81 to 0.61) or the incidence of dementia (HR 0.94, 95% CI 0.72 to 1.24). A pilot study with 60 participants used a higher dose of vitamin D3 (4000 IU on alternate days) and found preliminary evidence that this dose probably has no effect on cognitive function over six months.
We included data from one trial of zinc and copper supplementation with 1072 participants. There was moderate‐certainty evidence of little or no effect on overall cognitive function (MD 0.6 MMSE points, 95% CI ‐0.19 to 1.39) or on the incidence of cognitive impairment after 5 years to 10 years. A second smaller trial provided no usable data, but reported no cognitive effects of six months of supplementation with zinc gluconate.
From one study with 3711 participants, there was low‐certainty evidence of no effect of approximately five years of selenium supplementation on the incidence of dementia (HR 0.83, 95% CI 0.61 to 1.13).
Finally, we included three trials of complex supplements (combinations of B vitamins, antioxidant vitamins, and minerals) with 6306 participants. From the one trial which assessed overall cognitive function, there was low‐certainty evidence of little or no effect on the TICS (MD after a mean of 8.5 years 0.12, 95% CI ‐0.14 to 0.38).
Authors' conclusions
We did not find evidence that any vitamin or mineral supplementation strategy for cognitively healthy adults in mid or late life has a meaningful effect on cognitive decline or dementia, although the evidence does not permit definitive conclusions. There were very few data on supplementation starting in midlife (< 60 years); studies designed to assess cognitive outcomes tended to be too short to assess maintenance of cognitive function; longer studies often had other primary outcomes and used cognitive measures which may have lacked sensitivity. The only positive signals of effect came from studies of long‐term supplementation with antioxidant vitamins. These may be the most promising for further research.
Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery ...smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350
nm linewidth, 700
nm pitch, and 350
nm depth. More than 90% of the cells aligned to the gratings, and were significantly elongated compared to the SMC cultured on non-patterned surfaces. The nuclei were also elongated and aligned. Proliferation of the cells was significantly reduced on the nanopatterned surfaces. The polarization of microtubule organizing centers (MTOC), which are associated with cell migration, of SMC cultured on nanopatterned surfaces showed a preference towards the axis of cell alignment in an in vitro wound healing assay. In contrast, the MTOC of SMC on non-patterned surfaces preferentially polarized towards the wound edge. It is proposed that this nanoimprinting technology will provide a valuable platform for studies in cell-substrate interactions and for development of medical devices with nanoscale features.
PDF
