Specific Genes Associated with Adverse Events of Methylphenidate Use in the Pediatric Population: A Systematic Literature Review.

J Res Pharm Pract. 2017 Apr-Jun;6(2):65-72

Authors: Joensen B, Meyer M, Aagaard L

Abstract
The aim of this study was to review empirical studies examining associations between candidate genes and adverse events (AEs) from methylphenidate (MPH) use in children and adolescents. The PubMed, EMBASE, CINAHL, and Web of Science databases were searched from their inception until March 2017. We included empirically based articles on pharmacogenetic studies in 0-17-year-old patients that investigated associations between specific candidate genes, their polymorphisms, and reported AEs. We extracted information about study design, setting, type of AE reporter, studied genes and their polymorphisms, age and gender, administered doses, method of genotyping, outcome measures, and main findings. A total of nine articles reporting information about four double-blind, placebo-controlled, cross-over studies and five open-label cohort studies were eligible for inclusion. Studies were published from 2006 onward and included a total of 998 patients (3-17-year-olds) diagnosed with attention-deficit hyperactivity disorder (ADHD). Studies predominantly involved males and lasted from 1 to 12 weeks. Studies used polymerase chain reaction and single nucleotide polymorphism genotyping methodology. Reported AEs were significantly associated with the following genes: appetite reduction (CES1*G); buccal-lingual movements (T1065G); diastolic blood pressure (ADRA2A Mspl C/C-GC); emotionality (DAT1*9/9); irritability (SNAP25 T1065G); picking (DRD4*7/DRD4*4); social withdrawal (DRD4*7/DRD4*4); somatic complaints (DAT1*10/10); tics (5-HTTLRP*S/L*L/L; SNAP25 T1065G); sadness (CES1*rsl12443580); and vegetative symptoms (5-HTTLPR). In conclusion, only few MPH pediatric pharmacogenetic studies were located, and large between-study heterogeneity was found. Studies were of naturalistic design and of short duration. They included small patient samples, poorly standardized treatment regimens, and limited outcome assessments. In the future, more pharmacogenomic studies in ADHD are needed, preferably using randomized, controlled study designs and of longer duration (more than 6 months).

PMID: 28616427 [PubMed - in process]

Mitochondria-Targeted Doxorubicin: A New Therapeutic Strategy against Doxorubicin-Resistant Osteosarcoma.

Mol Cancer Ther. 2016 Nov;15(11):2640-2652

Authors: Buondonno I, Gazzano E, Jean SR, Audrito V, Kopecka J, Fanelli M, Salaroglio IC, Costamagna C, Roato I, Mungo E, Hattinger CM, Deaglio S, Kelley SO, Serra M, Riganti C

Abstract
Doxorubicin is one of the leading drugs for osteosarcoma standard chemotherapy. A total of 40% to 45% of high-grade osteosarcoma patients are unresponsive, or only partially responsive, to doxorubicin (Dox), due to the overexpression of the drug efflux transporter ABCB1/P-glycoprotein (Pgp). The aim of this work is to improve Dox-based regimens in resistant osteosarcomas. We used a chemically modified mitochondria-targeted Dox (mtDox) against Pgp-overexpressing osteosarcomas with increased resistance to Dox. Unlike Dox, mtDox accumulated at significant levels intracellularly, exerted cytotoxic activity, and induced necrotic and immunogenic cell death in Dox-resistant/Pgp-overexpressing cells, fully reproducing the activities exerted by anthracyclines in drug-sensitive tumors. mtDox reduced tumor growth and cell proliferation, increased apoptosis, primed tumor cells for recognition by the host immune system, and was less cardiotoxic than Dox in preclinical models of drug-resistant osteosarcoma. The increase in Dox resistance was paralleled by a progressive upregulation of mitochondrial metabolism. By widely modulating the expression of mitochondria-related genes, mtDox decreased mitochondrial biogenesis, the import of proteins and metabolites within mitochondria, mitochondrial metabolism, and the synthesis of ATP. These events were paralleled by increased reactive oxygen species production, mitochondrial depolarization, and mitochondria-dependent apoptosis in resistant osteosarcoma cells, where Dox was completely ineffective. We propose mtDox as a new effective agent with a safer toxicity profile compared with Dox that may be effective for the treatment of Dox-resistant/Pgp-positive osteosarcoma patients, who strongly need alternative and innovative treatment strategies. Mol Cancer Ther; 15(11); 2640-52. ©2016 AACR.

PMID: 27466354 [PubMed - indexed for MEDLINE]

The Right Pill for You.

Sci Am. 2016 Sep 20;315(4):46-51

Authors: Maron DF

PMID: 27798591 [PubMed - indexed for MEDLINE]

Lurbinectedin Specifically Triggers the Degradation of Phosphorylated RNA Polymerase II and the Formation of DNA Breaks in Cancer Cells.

Mol Cancer Ther. 2016 Oct;15(10):2399-2412

Authors: Santamaría Nuñez G, Robles CM, Giraudon C, Martínez-Leal JF, Compe E, Coin F, Aviles P, Galmarini CM, Egly JM

Abstract
We have defined the mechanism of action of lurbinectedin, a marine-derived drug exhibiting a potent antitumor activity across several cancer cell lines and tumor xenografts. This drug, currently undergoing clinical evaluation in ovarian, breast, and small cell lung cancer patients, inhibits the transcription process through (i) its binding to CG-rich sequences, mainly located around promoters of protein-coding genes; (ii) the irreversible stalling of elongating RNA polymerase II (Pol II) on the DNA template and its specific degradation by the ubiquitin/proteasome machinery; and (iii) the generation of DNA breaks and subsequent apoptosis. The finding that inhibition of Pol II phosphorylation prevents its degradation and the formation of DNA breaks after drug treatment underscores the connection between transcription elongation and DNA repair. Our results not only help to better understand the high specificity of this drug in cancer therapy but also improve our understanding of an important transcription regulation mechanism. Mol Cancer Ther; 15(10); 2399-412. ©2016 AACR.

PMID: 27630271 [PubMed - indexed for MEDLINE]

Strain-based HLA association analysis identified HLA-DRB1*09:01 associated with modern strain tuberculosis.

HLA. 2017 Jun 14;:

Authors: Toyo-Oka L, Mahasirimongkol S, Yanai H, Mushiroda T, Wattanapokayakit S, Wichukchinda N, Yamada N, Smittipat N, Juthayothin T, Palittapongarnpim P, Nedsuwan S, Kantipong P, Takahashi A, Kubo M, Sawanpanyalert P, Tokunaga K

Abstract
Tuberculosis (TB) occurs as a result of complex interactions between the host immune system and pathogen virulence factors. Human leukocyte antigen (HLA) class II molecules play an important role in the host immune system. However, no study has assessed the association between HLA class II genes and susceptibility to TB caused by specific strains. This study investigated the possible association of HLA class II genes with TB caused by modern and ancient Mycobacterium tuberculosis (MTB). The study included 682 patients with TB and 836 control subjects who were typed for HLA-DRB1 and HLA-DQB1 alleles. MTB strains were classified using a large sequence polymorphism typing method. Association analysis was performed using common HLA alleles and haplotypes in different MTB strains. HLA association analysis of patients infected with modern MTB strains showed significant association for HLA-DRB1*09:01 (odds ratio [OR] = 1.82; P-value = 9.88 × 10(-4) ) and HLA-DQB1*03:03 alleles (OR = 1.76; P-value = 1.31 × 10(-3) ) with susceptibility to TB. Haplotype analysis confirmed that these alleles were in strong linkage disequilibrium and did not exert an interactive effect. Thus, the results of this study showed an association between HLA class II genes and susceptibility to TB caused by modern MTB strains, suggesting the importance of strain-specific analysis to determine susceptibility genes associated with TB.

PMID: 28612994 [PubMed - as supplied by publisher]

Methods to analyze big data in pharmacogenomics research.

Pharmacogenomics. 2017 Jun 14;:

Authors: Li R, Kim D, Ritchie MD

Abstract
The scale and scope of pharmacogenomics research continues to expand as the cost and efficiency of molecular data generation techniques advance. These new technologies give rise to enormous opportunity for the identification of important genetic and genomic factors important for drug treatment response. With this opportunity come significant challenges. Most of these can be categorized as 'big data' issues, facing not only pharmacogenomics, but other fields in the life sciences as well. In this review, we describe some of the analysis techniques and tools being implemented for genetic/genomic discovery in pharmacogenomics.

PMID: 28612644 [PubMed - as supplied by publisher]

Involvement of cytochrome P450 in cisplatin treatment: implications for toxicity.

Cancer Chemother Pharmacol. 2017 Jun 13;:

Authors: Quintanilha JCF, de Sousa VM, Visacri MB, Amaral LS, Santos RMM, Zambrano T, Salazar LA, Moriel P

Abstract
PURPOSE: The aim of this study is to evaluate the relationship between the CYP450 enzyme family and cisplatin toxicity.
METHODS: This article examined a collection of studies suggesting that CYP450 enzymes may influence cisplatin toxicity. We performed a narrative mini-review.
RESULTS: The studies review showed that CYP450 enzymes have an important role in drug-induced hepatotoxicity and nephrotoxicity, mainly CYP2E1 and CYP4A11. The studies also suggested that the cisplatin and CYP2E1 interaction leads to the generation of reactive oxygen species (ROS) and other oxidants resulting in renal injury; and that ROS generated by both the use of cisplatin and by the CYP2E1 increases tissue damage, induces apoptosis, and causes liver failure.
CONCLUSIONS: We observed that there is an important relationship between CYP450 and cisplatin, involving increased toxicity. However, the possible mechanisms described for the involvement of CYP450 enzymes in nephrotoxicity and hepatotoxicity induced by cisplatin need to be confirmed by further studies. Therefore, there is a need for a deeper investigation focusing on cisplatin toxicity mediated by CYP450 enzymes, which would undoubtedly contribute to a better understanding of the mechanisms that have been implicated so far.

PMID: 28612092 [PubMed - as supplied by publisher]

Association of Polymorphisms in Pharmacogenetic Candidate Genes with Propofol Susceptibility.

Sci Rep. 2017 Jun 13;7(1):3343

Authors: Zhong Q, Chen X, Zhao Y, Liu R, Yao S

Abstract
Significant individual susceptibility to intravenous anesthetic propofol exists. The etiology of individual variability in the response to propofol may be influenced by genetic polymorphisms in metabolic and functional pathways. With current pharmacogenetics and modern molecular biology technologies, it is possible to study the influence of genetic polymorphisms on susceptibility to propofol. When inducing general anesthesia with intravenous propofol, high individual susceptibility to propofol was found. Using Sequenom MassARRAY single-nucleotide polymorphism (SNP) genotyping, we identified a mutation (rs6313) in the 5HT2A gene that was correlated to individual susceptibility to propofol effect-site concentration (Cep) and onset time of propofol induction. Carriers of the minor allele (G) of 5HT2A rs6313 required less propofol (20% decrease in Cep) and less time (40% decrease in onset time) to induce anesthesia. Moreover, associations were found between the gamma-aminobutyric acid (GABA) receptor SNP rs2279020 and the SCN9A SNP rs6746030 and the susceptibility of bispectral index (BIS) after propofol-induced anesthesia. In addition, dominant mutations in GABAA1 rs2279020, GABAA2 rs11503014, and CHRM2 rs1824024 were putatively associated with cardiovascular susceptibility to propofol anesthesia. No gene-gene interactions were found through a standardized measure of linkage disequilibrium and a multifactor dimensionality reduction analysis. Our results suggest that genetic polymorphisms related to mechanisms of propofol anesthesia are involved in propofol susceptibility.

PMID: 28611364 [PubMed - in process]

Mutational analysis of anal cancers demonstrates frequent PIK3CA mutations associated with poor outcome after salvage abdominoperineal resection.

Br J Cancer. 2016 Jun 14;114(12):1387-94

Authors: Cacheux W, Rouleau E, Briaux A, Tsantoulis P, Mariani P, Richard-Molard M, Buecher B, Dangles-Marie V, Richon S, Lazartigues J, Jeannot E, Farkhondeh F, Sastre-Garau X, de La Rochefordière A, Labib A, Falcou MC, Stevens D, Roth A, Roman-Roman S, Mitry E, Bièche I, Lièvre A

Abstract
BACKGROUND: A better understanding of the molecular profile of anal squamous cell carcinomas (ASCCs) is necessary to consider new therapeutic approaches, and the identification of prognostic and predictive factors for response to treatment.
METHODS: We retrospectively analysed tumours from ASCC patients for mutational analysis of KRAS, NRAS, HRAS, BRAF, PIK3CA, MET, TP53 and FBXW7 genes by HRM and Sanger sequencing analysis.
RESULTS: Specimens from 148 patients were analysed: 96 treatment-naive tumours and 52 recurrences after initial radiotherapy (RT) or chemoradiotherapy (CRT). Mutations of KRAS, PIK3CA, FBXW7 and TP53 genes were present in 3 (2.0%), 30 (20.3%), 9 (6.1%) and 7 tumours (4.7%), respectively. The distribution of the mutations was similar between treatment-naive tumours and recurrences, except for TP53 mutations being more frequent in recurrences (P=0.0005). In patients treated with abdominoperineal resection (APR) after relapse (n=38, median follow-up of 18.2 years), overall survival (OS) was significantly correlated with HPV16 status (P=0.048), gender (P=0.045) and PIK3CA mutation (P=0.037). The PIK3CA status retained its prognostic significance in Cox multivariate regression analysis (P=0.025).
CONCLUSIONS: Our study identified PIK3CA mutation as an independent prognostic factor in patients who underwent APR for ASCC recurrence, suggesting a potential benefit from adjuvant treatment and the evaluation of targeted therapies with PI3K/Akt/mTor inhibitors in PIK3CA-mutated patients.

PMID: 27219019 [PubMed - indexed for MEDLINE]

Prognostic value of a newly identified MALAT1 alternatively spliced transcript in breast cancer.

Br J Cancer. 2016 Jun 14;114(12):1395-404

Authors: Meseure D, Vacher S, Lallemand F, Alsibai KD, Hatem R, Chemlali W, Nicolas A, De Koning L, Pasmant E, Callens C, Lidereau R, Morillon A, Bieche I

Abstract
BACKGROUND: Epigenetic deregulation is considered as a new hallmark of cancer. The long non-coding RNA MALAT1 has been implicated in several cancers; however, its role in breast cancer is still little known.
METHODS: We used RT-PCR, in situ hybridisation, and RPPA methods to quantify (i) the full-length (FL) and an alternatively spliced variant (Δsv) of MALAT1, and (ii) a panel of transcripts and proteins involved in MALAT1 pathways, in a large series of breast tumours from patients with known clinical/pathological status and long-term outcome.
RESULTS: MALAT1 was overexpressed in 14% (63/446) of the breast tumours. MALAT1-overexpressed tumour epithelial cells showed marked diffuse nuclear signals and numerous huge nuclear speckles. Screening of the dbEST database led to the identification of Δsv-MALAT1, a major alternatively spliced MALAT1 transcript, with a very different expression pattern compared with FL-MALAT1. This alternative Δsv-MALAT1 transcript was mainly underexpressed (18.8%) in our breast tumour series. Multivariate analysis showed that alternative Δsv-MALAT1 transcript is an independent prognostic factor. Δsv-MALAT1 expression was associated with alterations of the pre-mRNAs alternative splicing machinery, and of the Drosha-DGCR8 complex required for non-coding RNA biogenesis. Alternative Δsv-MALAT1 transcript expression was associated to YAP protein status and with an activation of the PI3K-AKT pathway.
CONCLUSIONS: Our results reveal a complex expression pattern of various MALAT1 transcript variants in breast tumours, and suggest that this pattern of expressions should be taken into account to evaluate MALAT1 as predictive biomarker and therapeutic target.

PMID: 27172249 [PubMed - indexed for MEDLINE]

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Cardiovascular Pharmacogenomics and Cognitive Function in Patients with Schizophrenia.

Pharmacotherapy. 2017 Jun 12;:

Authors: Ward KM, Kraal AZ, Flowers SA, Ellingrod VL

Abstract
STUDY OBJECTIVE: To examine the impact of multiple risk alleles for cognitive dysfunction and cardiovascular disease risk on cognitive function, and to determine if these relationships varied by cognitive reserve (CR) or concomitant medication use in patients with schizophrenia.
DESIGN: Cross-sectional study.
SETTING: Ambulatory mental health centers.
PATIENTS: A total of 122 adults with a schizophrenia spectrum diagnosis who were maintained on a stable antipsychotic regimen for at least 6 months prior to study enrollment; patients were divided into three CR groups based on years of formal education: no high school completion or equivalent (low-education group [18 patients]); completion of high school or equivalent (moderate-education group [36 patients]; or any degree of post-high school education (high-education group [68 patients]).
MEASUREMENTS AND MAIN RESULTS: The following pharmacogenomic variants were genotyped for each patient: AGT M268T (rs699), ACE insertion/deletion (or ACE I/D, rs1799752), and APOE ε2, ε3, and ε4 (rs429358 and rs7412). Risk allele carrier status (identified per gene as AGT M268 T carriers, ACE D carriers, and APOE ε4 carriers) was not significantly different among CR groups. The Brief Assessment of Cognition in Schizophrenia (BACS) scale was used to assess cognitive function. The mean ± SD patient age was 43.9 ± 11.6 years. Cardiovascular risk factors such as hypertension and hyperlipidemia diagnoses, and use of antihypertensive and lipid-lowering agents, did not significantly differ among CR groups. Mixed modeling revealed that risk allele carrier status was significantly associated with lower verbal memory scores for ACE D and APOE ε4 carriers, but AGT T carrier status was significantly associated with higher verbal memory scores (p=0.0188, p=0.0055, and p=0.0058, respectively). These results were only significant in the low-education group. Additionally, medication-gene interactions were not significant predictors of BACS scores.
CONCLUSION: ACE D and APOE ε4 carrier status, independent of medication use, was associated with lower verbal memory scores in patients with schizophrenia who had relatively lower CR, as identified by formal education. These results suggest that increasing CR may be protective against cognitive impairment that may be worsened by select cardiovascular risk alleles in patients with schizophrenia. This article is protected by copyright. All rights reserved.

PMID: 28605058 [PubMed - as supplied by publisher]

Clinical Trial Designs to Support Clinical Utility of Pharmacogenomic Testing.

Pharmacotherapy. 2017 Jun 12;:

Authors: Drozda K, Pacanowski MA

Abstract
Advancing the use of biomarkers and pharmacogenomics has been a key priority area for the Food and Drug Administration (FDA). The FDA offers prescribing recommendations to manage approximately 100 gene-drug interactions, and multiple institutions around the United States and abroad have incorporated genomic testing into patient care. However, the penetration of pharmacogenomic testing remains incomplete. In this perspective, we summarize the evidence streams to support the clinical utility of pharmacogenomic testing and its transition into clinical practice. This article is protected by copyright. All rights reserved.

PMID: 28605049 [PubMed - as supplied by publisher]

Large-scale association analysis identifies new lung cancer susceptibility loci and heterogeneity in genetic susceptibility across histological subtypes.

Nat Genet. 2017 Jun 12;:

Authors: McKay JD, Hung RJ, Han Y, Zong X, Carreras-Torres R, Christiani DC, Caporaso NE, Johansson M, Xiao X, Li Y, Byun J, Dunning A, Pooley KA, Qian DC, Ji X, Liu G, Timofeeva MN, Bojesen SE, Wu X, Le Marchand L, Albanes D, Bickeböller H, Aldrich MC, Bush WS, Tardon A, Rennert G, Teare MD, Field JK, Kiemeney LA, Lazarus P, Haugen A, Lam S, Schabath MB, Andrew AS, Shen H, Hong YC, Yuan JM, Bertazzi PA, Pesatori AC, Ye Y, Diao N, Su L, Zhang R, Brhane Y, Leighl N, Johansen JS, Mellemgaard A, Saliba W, Haiman CA, Wilkens LR, Fernandez-Somoano A, Fernandez-Tardon G, van der Heijden HFM, Kim JH, Dai J, Hu Z, Davies MPA, Marcus MW, Brunnström H, Manjer J, Melander O, Muller DC, Overvad K, Trichopoulou A, Tumino R, Doherty JA, Barnett MP, Chen C, Goodman GE, Cox A, Taylor F, Woll P, Brüske I, Wichmann HE, Manz J, Muley TR, Risch A, Rosenberger A, Grankvist K, Johansson M, Shepherd FA, Tsao MS, Arnold SM, Haura EB, Bolca C, Holcatova I, Janout V, Kontic M, Lissowska J, Mukeria A, Ognjanovic S, Orlowski TM, Scelo G, Swiatkowska B, Zaridze D, Bakke P, Skaug V, Zienolddiny S, Duell EJ, Butler LM, Koh WP, Gao YT, Houlston RS, McLaughlin J, Stevens VL, Joubert P, Lamontagne M, Nickle DC, Obeidat M, Timens W, Zhu B, Song L, Kachuri L, Artigas MS, Tobin MD, Wain LV, SpiroMeta Consortium, Rafnar T, Thorgeirsson TE, Reginsson GW, Stefansson K, Hancock DB, Bierut LJ, Spitz MR, Gaddis NC, Lutz SM, Gu F, Johnson EO, Kamal A, Pikielny C, Zhu D, Lindströem S, Jiang X, Tyndale RF, Chenevix-Trench G, Beesley J, Bossé Y, Chanock S, Brennan P, Landi MT, Amos CI

Abstract
Although several lung cancer susceptibility loci have been identified, much of the heritability for lung cancer remains unexplained. Here 14,803 cases and 12,262 controls of European descent were genotyped on the OncoArray and combined with existing data for an aggregated genome-wide association study (GWAS) analysis of lung cancer in 29,266 cases and 56,450 controls. We identified 18 susceptibility loci achieving genome-wide significance, including 10 new loci. The new loci highlight the striking heterogeneity in genetic susceptibility across the histological subtypes of lung cancer, with four loci associated with lung cancer overall and six loci associated with lung adenocarcinoma. Gene expression quantitative trait locus (eQTL) analysis in 1,425 normal lung tissue samples highlights RNASET2, SECISBP2L and NRG1 as candidate genes. Other loci include genes such as a cholinergic nicotinic receptor, CHRNA2, and the telomere-related genes OFBC1 and RTEL1. Further exploration of the target genes will continue to provide new insights into the etiology of lung cancer.

PMID: 28604730 [PubMed - as supplied by publisher]

Personalized Medicine: New Perspectives for the Diagnosis and the Treatment of Renal Diseases.

Int J Mol Sci. 2017 Jun 10;18(6):

Authors: Gluba-Brzózka A, Franczyk B, Olszewski R, Banach M, Rysz J

Abstract
The prevalence of renal diseases is rising and reaching 5-15% of the adult population. Renal damage is associated with disturbances of body homeostasis and the loss of equilibrium between exogenous and endogenous elements including drugs and metabolites. Studies indicate that renal diseases are influenced not only by environmental but also by genetic factors. In some cases the disease is caused by mutation in a single gene and at that time severity depends on the presence of one or two mutated alleles. In other cases, renal disease is associated with the presence of alteration within a gene or genes, but environmental factors are also necessary for the development of disease. Therefore, it seems that the analysis of genetic aspects should be a natural component of clinical and experimental studies. The goal of personalized medicine is to determine the right drug, for the right patient, at the right time. Whole-genome examinations may help to change the approach to the disease and the patient resulting in the creation of "personalized medicine" with new diagnostic and treatment strategies designed on the basis of genetic background of each individual. The identification of high-risk patients in pharmacogenomics analyses will help to avoid many unwarranted side effects while optimizing treatment efficacy for individual patients. Personalized therapies for kidney diseases are still at the preliminary stage mainly due to high costs of such analyses and the complex nature of human genome. This review will focus on several areas of interest: renal disease pathogenesis, diagnosis, treatment, rate of progression and the prediction of prognosis.

PMID: 28604601 [PubMed - in process]

The impact of clinical and genetic factors on ticagrelor and clopidogrel antiplatelet therapy.

Pharmacogenomics. 2017 Jun 12;:

Authors: Tatarunas V, Kupstyte N, Zaliunas R, Giedraitiene A, Lesauskaite V

Abstract
AIM: To determine clinically significant factors which may alter the effect of dual antiplatelet therapy with aspirin and ticagrelor or clopidogrel in patients who had undergone percutaneous coronary intervention and stent implantation.
MATERIALS & METHODS: The study included 378 patients. All the patients had undergone percutaneous coronary intervention and stent implantation. Platelet aggregation and genotyping for CYP2C19 *2 (rs4244285) and CYP4F2 (rs2108622, rs1558139, rs3093135 and rs2074902) was performed.
RESULTS: Significantly lower platelet aggregation values (%(agr)) were detected in ticagrelor users who carried CYP4F2 rs3093135 TT variant (14.67 ± 5.07%(agr)) versus AA (22.88 ± 6.30%(agr)), p = 0.0004, or AT (20.56 ± 6.51%(agr)), p = 0.0126.
CONCLUSION: Results of the current study showed that CYP4F2 rs3093135 TT variant carriers had a higher antiplatelet effect of ticagrelor, and more frequently had nonprocedural bleeding during ticagrelor therapy, as compared with AA and AT variant carriers.

PMID: 28604225 [PubMed - as supplied by publisher]

In vitro metabolism of exemestane by hepatic cytochrome P450s: impact of nonsynonymous polymorphisms on formation of the active metabolite 17β-dihydroexemestane.

Pharmacol Res Perspect. 2017 Jun;5(3):e00314

Authors: Peterson A, Xia Z, Chen G, Lazarus P

Abstract
Exemestane (EXE) is an endocrine therapy commonly used by postmenopausal women with hormone-responsive breast cancer due to its potency in inhibiting aromatase-catalyzed estrogen synthesis. Preliminary in vitro studies sought to identify phase I EXE metabolites and hepatic cytochrome P450s (CYP450s) that participate in EXE biotransformation. Phase I metabolites were identified by incubating EXE with HEK293-overexpressed CYP450s. CYP450s 1A2, 2C8, 2C9, 2C19, 2D6, 3A4, and 3A5 produce 17β-dihydroexemestane (17β-DHE), an active major metabolite, as well as two inactive metabolites. 17β-DHE formation in pooled human liver microsomes subjected to isoform-specific CYP450 inhibition was also monitored using tandem mass spectrometry. 17β-DHE production in human liver microsomes was unaffected by isoform-specific inhibition of CYP450s 2A6, 2B6, and 2E1 but decreased 12-39% following inhibition of drug-metabolizing enzymes from CYP450 subfamilies 1A, 2C, 2D, and 3A. These results suggest that redundancy exists in the EXE metabolic pathway with multiple hepatic CYP450s catalyzing 17β-DHE formation in vitro. To further expand the knowledge of phase I EXE metabolism, the impact of CYP450 genetic variation on 17β-DHE formation was assessed via enzyme kinetic parameters. Affinity for EXE substrate and enzyme catalytic velocity were calculated for hepatic wild-type CYP450s and their common nonsynonymous variants by monitoring the reduction of EXE to 17β-DHE. Several functional polymorphisms in xenobiotic-metabolizing CYP450s 1A2, 2C8, 2C9, and 2D6 resulted in deviant enzymatic activity relative to wild-type enzyme. Thus, it is possible that functional polymorphisms in EXE-metabolizing CYP450s contribute to inter-individual variability in patient outcomes by mediating overall exposure to the drug and its active metabolite, 17β-DHE.

PMID: 28603633 [PubMed - in process]

Exemestane potency is unchanged by common nonsynonymous polymorphisms in CYP19A1: results of a novel anti-aromatase activity assay examining exemestane and its derivatives.

Pharmacol Res Perspect. 2017 Jun;5(3):e00313

Authors: Peterson A, Xia Z, Chen G, Lazarus P

Abstract
Exemestane (EXE) treats estrogen receptor positive (ER+) breast cancer in postmenopausal women by inhibiting the estrogen-synthesizing cytochrome P450 CYP19A1. Variability in the severity and incidence of side effects as well as overall drug efficacy may be partially explained by genetic factors, including nonsynonymous variation in CYP19A1, also known as aromatase. The present study identified phase I EXE metabolites in human liver microsomes (HLM) and investigated mechanisms that may alter the extent of systemic estrogen deprivation in EXE-treated women with breast cancer, including whether functional polymorphisms in aromatase cause differential inhibition by EXE and whether EXE metabolites possess anti-aromatase activity. The potency of EXE and ten of its derivatives was measured with HEK293-overexpressed wild type aromatase (CYP19A1*1) using a rapid novel UPLC tandem mass spectrometry method. Of the ten compounds assayed, five were poor inhibitors (IC 50 ˃ 50 μmol/L) of wild type aromatase while five others, including the major metabolite, 17β-dihydroexemestane (17β-DHE), exhibited moderate potency, with IC 50 values ranging between 1.2 and 7.1 μmol/L. The anti-aromatase activity of EXE was also tested with two common allozymes, aromatase(Thr201Met) (CYP19A1*3) and aromatase(Arg264Cys) (CYP19A1*4). Differential inhibition of variant aromatase is unlikely to account for variable clinical outcomes as EXE-mediated inhibition of aromatase(Thr201Met) (IC 50 = 0.86 ± 0.12 μmol/L) and aromatase(Arg264Cys) (IC 50 = 1.7 ± 0.65 μmol/L) did not significantly differ from wild type (IC 50 = 0.92 ± 0.17 μmol/L). Although less potent than the parent drug, these results suggest that active metabolites may contribute to the therapeutic mechanism of EXE.

PMID: 28603632 [PubMed - in process]

Pharmacogenetics in inflammatory bowel disease: understanding treatment response and personalizing therapeutic strategies.

Pharmgenomics Pers Med. 2017;10:197-204

Authors: Yamamoto-Furusho JK

Abstract
Inflammatory bowel disease (IBD) is a chronic and heterogeneous disorder characterized by remitting and relapsing periods of activity. Pharmacogenetics refers to the study of the effect of inheritance on individual variation in drug responses. Several drug-related markers in IBD patients have been identified in order to predict the response to medical treatment including biological therapy as well as the reduction of adverse events. In the future, the treatment of IBD should be personalized in its specific profile to provide the most efficacious treatment with lack of adverse events.

PMID: 28603427 [PubMed - in process]

Hepatic Overexpression of CD36 Improves Glycogen Homeostasis and Attenuates High-Fat Diet-Induced Hepatic Steatosis and Insulin Resistance.

Mol Cell Biol. 2016 Nov 01;36(21):2715-2727

Authors: Garbacz WG, Lu P, Miller TM, Poloyac SM, Eyre NS, Mayrhofer G, Xu M, Ren S, Xie W

Abstract
The common complications in obesity and type 2 diabetes include hepatic steatosis and disruption of glucose-glycogen homeostasis, leading to hyperglycemia. Fatty acid translocase (FAT/CD36), whose expression is inducible in obesity, is known for its function in fatty acid uptake. Previous work by us and others suggested that CD36 plays an important role in hepatic lipid homeostasis, but the results have been conflicting and the mechanisms were not well understood. In this study, by using CD36-overexpressing transgenic (CD36Tg) mice, we uncovered a surprising function of CD36 in regulating glycogen homeostasis. Overexpression of CD36 promoted glycogen synthesis, and as a result, CD36Tg mice were protected from fasting hypoglycemia. When challenged with a high-fat diet (HFD), CD36Tg mice showed unexpected attenuation of hepatic steatosis, increased very low-density lipoprotein (VLDL) secretion, and improved glucose tolerance and insulin sensitivity. The HFD-fed CD36Tg mice also showed decreased levels of proinflammatory hepatic prostaglandins and 20-hydroxyeicosatetraenoic acid (20-HETE), a potent vasoconstrictive and proinflammatory arachidonic acid metabolite. We propose that CD36 functions as a protective metabolic sensor in the liver under lipid overload and metabolic stress. CD36 may be explored as a valuable therapeutic target for the management of metabolic syndrome.

PMID: 27528620 [PubMed - indexed for MEDLINE]