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1.
Eur J Neurol ; 25(9): 1148-e102, 2018 09.
Article in English | MEDLINE | ID: mdl-29747220

ABSTRACT

BACKGROUND AND PURPOSE: Headache has been associated with various lifestyle and psychosocial factors, one of which is smoking. The aim of the present study was to investigate whether the association between smoking intensity and headache is likely to be causal. METHOD: A total of 58 316 participants from the Nord-Trøndelag Health (HUNT) study with information on headache status were genotyped for the rs1051730 C>T single-nucleotide polymorphism (SNP). The SNP was used as an instrument for smoking intensity in a Mendelian randomization analysis. The association between rs1051730 T alleles and headache was estimated by odds ratios with 95% confidence intervals. Additionally, the association between the SNP and migraine or non-migrainous headache versus no headache was investigated. All analyses were adjusted for age and sex. RESULTS: There was no strong evidence that the rs1051730 T allele was associated with headache in ever smokers (odds ratio 0.99, 95% confidence interval 0.95-1.02). Similarly, there was no association between the rs1051730 T allele and migraine or non-migrainous headache versus no headache. CONCLUSION: The findings from this study do not support that there is a strong causal relationship between smoking intensity and any type of headache. Larger Mendelian randomization studies are required to examine whether higher smoking quantity can lead to a moderate increase in the risk of headache subtypes.


Subject(s)
Headache/epidemiology , Mendelian Randomization Analysis , Smoking/adverse effects , Smoking/epidemiology , Adult , Aged , Aged, 80 and over , Causality , Female , Genotype , Headache/genetics , Humans , Male , Middle Aged , Migraine Disorders/epidemiology , Migraine Disorders/etiology , Norway/epidemiology , Polymorphism, Single Nucleotide/genetics , Sex Factors , Smoking/genetics , Young Adult
2.
Osteoarthritis Cartilage ; 25(6): 817-823, 2017 06.
Article in English | MEDLINE | ID: mdl-28049019

ABSTRACT

OBJECTIVE: Smoking has been associated with a reduced risk of hip and knee osteoarthritis (OA) and subsequent joint replacement. The aim of the present study was to assess whether the observed association is likely to be causal. METHOD: 55,745 participants of a population-based cohort were genotyped for the rs1051730 C > T single-nucleotide polymorphism (SNP), a proxy for smoking quantity among smokers. A Mendelian randomization analysis was performed using rs1051730 as an instrument to evaluate the causal role of smoking on the risk of hip or knee replacement (combined as total joint replacement (TJR)). Association between rs1051730 T alleles and TJR was estimated by hazard ratios (HRs) and 95% confidence intervals (CIs). All analyses were adjusted for age and sex. RESULTS: Smoking quantity (no. of cigarettes) was inversely associated with TJR (HR 0.97, 95% CI 0.97-0.98). In the Mendelian randomization analysis, rs1051730 T alleles were associated with reduced risk of TJR among current smokers (HR 0.84, 95% CI 0.76-0.98, per T allele), however we found no evidence of association among former (HR 0.97, 95% CI 0.88-1.07) and never smokers (HR 0.97, 95% CI 0.89-1.06). Neither adjusting for body mass index (BMI), cardiovascular disease (CVD) nor accounting for the competing risk of mortality substantially changed the results. CONCLUSION: This study suggests that smoking may be causally associated with the reduced risk of TJR. Our findings add support to the inverse association found in previous observational studies. More research is needed to further elucidate the underlying mechanisms of this causal association.


Subject(s)
Arthroplasty, Replacement, Hip/statistics & numerical data , Arthroplasty, Replacement, Knee/statistics & numerical data , Osteoarthritis, Hip/surgery , Osteoarthritis, Knee/surgery , Smoking/epidemiology , Causality , Female , Humans , Logistic Models , Male , Mendelian Randomization Analysis , Middle Aged , Multigene Family , Nerve Tissue Proteins/genetics , Odds Ratio , Polymorphism, Single Nucleotide , Proportional Hazards Models , Receptors, Nicotinic/genetics , Risk , Smoking/genetics
3.
Acta Anaesthesiol Scand ; 60(8): 1084-91, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27113810

ABSTRACT

BACKGROUND: Genetic variability contributes to variable clinical response to opioids. This study emerged from the observation of three Norwegian patients who showed no or extraordinary poor response to very high doses of opioids. We suspected a genetic defect and applied a 'most likely candidate gene' approach to investigate this possibility. METHODS: DNA sequencing was used to search for mutations in coding regions of the OPRM1 gene, encoding the µ opioid receptor (hMOR), in one patient. The remaining two patients, and two cohorts comprising 2158 European cancer pain patients and 600 Norwegian healthy volunteers, respectively, were genotyped using a custom-made TaqMan SNP allelic discrimination assay. RESULTS: DNA sequencing disclosed a homozygous, inactivating Arg181Cys mutation in hMOR in the patient who showed no effects from opioids. The two patients with poor effect from very high doses of opioids were both heterozygous for the mutation. Six heterozygous patients identified among the European cancer patients all used high doses of opioids and/or reported inferior effect on their pain. About one in every 100 Norwegians is heterozygous for the mutation. CONCLUSIONS: The Arg181Cys mutation occurs at clinically relevant frequencies and produces a signaling dead hMOR which may abolish or significantly reduce opioid effects in affected individuals. Anesthesiologists and practitioners in pain medicine should be aware of this mutation as a possible explanation for inefficiency of opioids and consider genotyping in relevant cases. Individuals homozygous for the mutation may need a highly personalized approach to pain therapy.


Subject(s)
Mutation , Receptors, Opioid, mu/genetics , Adult , Aged , Aged, 80 and over , Analgesics, Opioid/pharmacology , Female , Humans , Male , Middle Aged
4.
Psychol Med ; 43(4): 711-9, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22687325

ABSTRACT

BACKGROUND: Cigarette smoking is strongly associated with mental illness but the causal direction of the association is uncertain. We investigated the causal relationship between smoking and symptoms of anxiety and depression in the Norwegian HUNT study using the rs1051730 single nucleotide polymorphism (SNP) variant located in the nicotine acetylcholine receptor gene cluster on chromosome 15 as an instrumental variable for smoking phenotypes. Among smokers, this SNP is robustly associated with smoking quantity and nicotine dependence. Method In total, 53 601 participants were genotyped for the rs1051730 SNP and provided information on smoking habits and symptoms of anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). RESULTS: Self-reported smoking was positively associated with the prevalence of both anxiety and depression, and the measured polymorphism was positively associated with being a current smoker and the number of cigarettes smoked in current smokers. In the sample as a whole, risk of anxiety increased with each affected T allele [odds ratio (OR) 1.06, 95% confidence interval (CI) 1.02-1.09, p = 0.002] but there was no association with depression (p = 0.31). However, we found no clear association of the polymorphism with either anxiety (OR 1.03, 95% CI 0.97-1.09, p = 0.34) or depression (OR 1.02, 95% CI 0.95-1.09, p = 0.62) among smokers. CONCLUSIONS: As there was no association of the smoking-related rs1051730 SNP with anxiety and depression among smokers, the results suggest that smoking is not a cause of anxiety and depression.


Subject(s)
Anxiety Disorders/epidemiology , Depressive Disorder/epidemiology , Mendelian Randomization Analysis , Receptors, Nicotinic/genetics , Smoking/epidemiology , Adult , Alleles , Anxiety Disorders/genetics , Body Mass Index , Causality , Chromosomes, Human, Pair 15/genetics , Depressive Disorder/genetics , Female , Genetic Predisposition to Disease/epidemiology , Genetic Predisposition to Disease/genetics , Humans , Logistic Models , Male , Middle Aged , Norway/epidemiology , Polymorphism, Single Nucleotide/genetics , Pregnancy , Prevalence , Psychiatric Status Rating Scales , Self Report , Smoking/genetics , Smoking/psychology , Young Adult
5.
Acta Anaesthesiol Scand ; 57(1): 89-99, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23167532

ABSTRACT

BACKGROUND: Changes in skin conductance (SC), clinical stress score (CSS), the bispectral index spectroscopy (BIS) index and the variation in the BIS index may be used to monitor responses to nociceptive stimuli. We wanted to examine these methods during noxious stimulation during general anaesthesia and if the responses were associated with variability in genes related to pain. METHODS: Sixty patients, given propofol to a BIS level of 40-50, were stimulated with standardised tetanic electrical stimuli during propofol infusion, plasma level of 3 µg/ml alone, or together with remifentanil target plasma level of 3 ng/ml or 10 ng/ml. The CSS, SC, BIS index and the variability of the BIS index were registered. The inter-individual variation in nociceptive responses was analysed for co-variation with genotypes of 89 single nucleotide polymorphisms from 23 candidate genes. RESULTS: During tetanic stimuli, CSS and SC increased significantly and were attenuated with increasing level of remifentanil, different from the BIS index and the variation in the BIS index. Polymorphisms in the P-glycoprotein (ABCB1), tachykinin 1 receptor (TACR1), dopamine receptor D3 (DRD3) and beta arrestin 2 (ARRB2) genes were associated with the co-variation in SC variables or CSS response or both during standardised nociceptive stimuli (P < 0.05). Because of no corrections for multiple testing, the genetic analyses are explorative, and associations must be tested in further studies. CONCLUSION: This exploratory study suggests genes that may be tested further with relation to nociceptive response during anaesthesia. SC and CSS may be useful tools for monitoring nociceptive response during general anaesthesia.


Subject(s)
Anesthesia, General , Nociception/drug effects , Pain Measurement/methods , Pain/genetics , Anesthetics, Intravenous/blood , Area Under Curve , Consciousness Monitors , Electric Stimulation , Female , Galvanic Skin Response , Genetic Variation , Genotype , Gynecologic Surgical Procedures , Humans , Individuality , Laparoscopy , Muscle Contraction/drug effects , Piperidines/blood , Polymorphism, Single Nucleotide , Preanesthetic Medication , Remifentanil
6.
Diabetologia ; 55(5): 1310-8, 2012 May.
Article in English | MEDLINE | ID: mdl-22297581

ABSTRACT

AIMS: The aetiology of latent autoimmune diabetes in adults (LADA), assessed by autoimmune markers, is insufficiently clarified. We cross-sectionally investigated the prevalence and prospectively the prediabetic and postdiabetic presence of antibodies to glutamic acid decarboxylase (GADA), insulinoma-associated protein 2 and zinc transporter 8 in LADA and in type 1 diabetes. METHODS: We included 208 'classic' type 1, 161 LADA and 302 type 2 diabetic cases from the second (HUNT2: 1995­1997) and third (HUNT3: 2006­2008) Nord-Trøndelag health surveys. Prospective data were available for 59 type 1, 44 LADA and 302 type 2 diabetic cases followed from HUNT2 to HUNT3. From HUNT3, 24 type 1 diabetic and 31 LADA incident cases were available. RESULTS: Cross-sectionally, 90% of LADA cases were positive for only one antibody (10% multiple-antibodypositive). Prospectively, 59% of GADA-positive LADA patients in HUNT2 were no longer positive in HUNT3. LADA patients who became negative possessed less frequently risk HLA haplotypes and were phenotypically more akin to those with type 2 diabetes than to those who stayed positive. Still, those losing positivity differed from those with type 2 diabetes by lower C-peptide levels (p = 0.009). Of incident LADA cases in HUNT3, 64% were already antibody-positive in HUNT2, i.e. before diabetes diagnosis. These incident LADA cases were phenotypically more akin to type 1 diabetes than were those who did not display positivity in HUNT2. CONCLUSION/INTERPRETATION: The pattern of antibodies, the postdiabetic loss or persistence as well as the prediabetic absence or presence of antibodies influence LADA phenotypes. Time-dependent presence or absence of antibodies adds new modalities to the heterogeneity of LADA.


Subject(s)
Autoantibodies/blood , Autoantibodies/immunology , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/immunology , Adult , Aged , C-Peptide/blood , C-Peptide/immunology , Cation Transport Proteins/immunology , Cross-Sectional Studies , Diabetes Mellitus, Type 1/genetics , Female , Glutamate Decarboxylase/immunology , HLA Antigens/genetics , HLA Antigens/immunology , Haplotypes , Humans , Male , Middle Aged , Norway/epidemiology , Prediabetic State/blood , Prediabetic State/genetics , Prediabetic State/immunology , Prevalence , Receptor-Like Protein Tyrosine Phosphatases, Class 8/immunology , Risk , Zinc Transporter 8
7.
Pharmacogenomics J ; 12(5): 412-6, 2012 Oct.
Article in English | MEDLINE | ID: mdl-21747411

ABSTRACT

The European Pharmacogenetic Opioid Study (EPOS) of a large series of European cancer patients treated with opioids was carried out to assess the influence of genetics on cancer pain relief. As response to opioid therapy was associated with the patients' country of origin, we tested whether population stratification might represent a confounding factor in the analysis of genetic control of response to opioid therapy. From the whole EPOS series representing 2294 patients' genotypes for 379 single-nucleotide polymorphisms (SNPs), we extracted 117 autosomal SNPs with minor allele frequency>0.28 to obtain highly informative genetic markers, and analyzed the SNPs in 1724 individuals showing <20% missing genotypes. Use of the AWclust program to detect clusters of genetically related individuals in the EPOS series showed that the 117-SNP panel distinguished four main European subgroups statistically associated with ethnicity, but not with country of origin or with the pain relief phenotype. Subethnic European groups of genetically related individuals exist that can be correctly identified using an ∼100-SNP panel. Such genetic clustering may control for admixture in association studies and may allow discrimination between genetic and environmental effects on phenotypes showing association with country of origin, as in the case of pain relief.


Subject(s)
Analgesics, Opioid/administration & dosage , Neoplasms , Pain Management , Pain , Analgesics, Opioid/metabolism , Gene Frequency , Genetic Association Studies , Genetic Variation , Genetics, Population , Humans , Neoplasms/complications , Neoplasms/genetics , Pain/complications , Pain/genetics , Polymorphism, Single Nucleotide , White People
8.
Br J Cancer ; 105(8): 1244-51, 2011 Oct 11.
Article in English | MEDLINE | ID: mdl-21934689

ABSTRACT

BACKGROUND: Cachexia has major impact on cancer patients' morbidity and mortality. Future development of cachexia treatment needs methods for early identification of patients at risk. The aim of the study was to validate nine single-nucleotide polymorphisms (SNPs) previously associated with cachexia, and to explore 182 other candidate SNPs with the potential to be involved in the pathophysiology. METHOD: A total of 1797 cancer patients, classified as either having severe cachexia, mild cachexia or no cachexia, were genotyped. RESULTS: After allowing for multiple testing, there was no statistically significant association between any of the SNPs analysed and the cachexia groups. However, consistent with prior reports, two SNPs from the acylpeptide hydrolase (APEH) gene showed suggestive statistical significance (P=0.02; OR, 0.78). CONCLUSION: This study failed to detect any significant association between any of the SNPs analysed and cachexia; although two SNPs from the APEH gene had a trend towards significance. The APEH gene encodes the enzyme APEH, postulated to be important in the endpoint of the ubiquitin system and thus the breakdown of proteins into free amino acids. In cachexia, there is an extensive breakdown of muscle proteins and an increase in the production of acute phase proteins in the liver.


Subject(s)
Cachexia/genetics , Neoplasms/complications , Body Mass Index , Cachexia/complications , Humans , Polymorphism, Single Nucleotide
9.
Pain ; 152(5): 1139-1145, 2011 May.
Article in English | MEDLINE | ID: mdl-21398039

ABSTRACT

Cancer pain patients need variable opioid doses. Preclinical and clinical studies suggest that opioid efficacy is related to genetic variability. However, the studies have small samples, findings are not replicated, and several candidate genes have not been studied. Therefore, a study of genetic variability with opioid doses in a large population using a confirmatory validation population was warranted. We recruited 2294 adult European patients using a World Health Organization (WHO) step III opioid and analyzed single nucleotide polymorphisms (SNPs) in genes with a putative influence on opioid mechanisms. The patients' mean age was 62.5 years, and the average pain intensity was 3.5. The patients' primary opioids were morphine (n=830), oxycodone (n=446), fentanyl (n=699), or other opioids (n=234). Pain intensity, time on opioids, age, gender, performance status, and bone or CNS metastases predicted opioid dose and were included as covariates. The patients were randomly divided into 1 development sample and 1 validation sample. None of 112 SNPs in the 25 candidate genes OPRM1, OPRD1, OPRK1, ARRB2, GNAZ, HINT1, Stat6, ABCB1, COMT, HRH1, ADRA2A, MC1R, TACR1, GCH1, DRD2, DRD3, HTR3A, HTR3B, HTR2A, HTR3C, HTR3D, HTR3E, HTR1, or CNR1 showed significant associations with opioid dose in both the development and the validation analyzes. These findings do not support the use of pharmacogenetic analyses for the assessed SNPs to guide opioid treatment. The study also demonstrates the importance of validating findings obtained in genetic association studies to avoid reporting spurious associations as valid findings. To elicit knowledge about new genes that influence pain and the need for opioids, strategies other than the candidate gene approach is needed.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Opioid-Related Disorders/genetics , Pain/genetics , Receptors, Opioid/genetics , Signal Transduction/genetics , Analgesics, Opioid/therapeutic use , Chi-Square Distribution , Europe/epidemiology , Female , Genome-Wide Association Study , Humans , Male , Middle Aged , Neoplasms/complications , Opioid-Related Disorders/etiology , Pain/drug therapy , Pain/etiology , Pain Measurement , Polymorphism, Single Nucleotide/genetics , Signal Transduction/drug effects
10.
Mol Hum Reprod ; 17(7): 439-46, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21355050

ABSTRACT

The etiology of preeclampsia is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. Although many candidate genes for preeclampsia have been suggested and studied, the specific causative genes still remain to be identified. Catechol-O-methyltransferase (COMT) is an enzyme involved in catecholamine and estrogen degradation and has recently been ascribed a role in development of preeclampsia. In the present study, we have examined the COMT gene by genotyping the functional Val108/158Met polymorphism (rs4680) and an additional single-nucleotide polymorphism, rs6269, predicting COMT activity haplotypes in a large Norwegian case/control cohort (n(cases)= 1135, n(controls)= 2262). A low COMT activity haplotype is associated with recurrent preeclampsia in our cohort. This may support the role of redox-regulated signaling and oxidative stress in preeclampsia pathogenesis as suggested by recent studies in a genetic mouse model. The COMT gene might be a genetic risk factor shared between preeclampsia and cardiovascular diseases.


Subject(s)
Catechol O-Methyltransferase/genetics , Haplotypes/genetics , Pre-Eclampsia/genetics , Female , Genetic Predisposition to Disease , Humans , Norway , Pregnancy , White People
11.
Palliat Med ; 22(4): 310-27, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18541635

ABSTRACT

The aim of this literature review is to summarize and discuss the available evidence for a relationship between polymorphisms in human genes and variability in opioid analgesia and side effects among patients treated for moderate or severe pain. The evidence supporting a role of certain alleles, genotypes or haplotypes in modulation of opioid analgesia is derived from a limited number of studies, a limited number of genes and a limited number of opioids. Although several interesting candidates have emerged as potentially relevant factors, only for one polymorphism, the prevalent 118A>G of the micro-opioid receptor, the accumulated evidence is sufficient to suggest a clinically relevant effect for an opioid used for moderate or severe pain. Still the data are valid only at the group level and cannot be used to predict treatment outcome in individual patients. Only a few of the symptoms often seen as opioid adverse effects in palliative care, such as nausea, vomiting, constipation and sedation, have been associated with genetic variants in various genes, but the results have been based on case reports, healthy volunteers or post-operative patients. So far, there is no clear evidence that genetic markers can be used to predict opioid efficacy or adverse effects in palliative care patients. This reflects the general lack of studies performed in the context of palliative care, the lack of sufficiently scaled studies and the lack of international standards for the assessment of subjective symptoms.


Subject(s)
Analgesics, Opioid/therapeutic use , Pain, Intractable/genetics , Palliative Care/methods , Polymorphism, Genetic/drug effects , Genetic Markers , Humans , Pain, Intractable/drug therapy
12.
Acta Anaesthesiol Scand ; 49(7): 902-8, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16045647

ABSTRACT

The individual variability of opioid pharmacology suggests that the patients' genetic disposition influences the response to opioids. Given the complexity of morphine pharmacology, variability may be caused by several genes. We review data which shows that variability in genes coding the enzyme metabolizing morphine (UGT2B7 gene), mu-opioid receptors (OPRM gene) and blood-brain barrier (BBB) transport of morphine by multidrug resistance transporters (MDR1 gene) influences the clinical efficacy of morphine. Furthermore, variability in an enzyme degrading catecholamines (COMT gene) alters the efficacy of morphine demonstrating that genetic variability in non-opioid systems may indirectly influence the clinical efficacy from morphine. Thus, results obtained so far strongly argue that opioid efficacy is partly related to inborn properties caused by genetic variability.


Subject(s)
Morphine/therapeutic use , Catechol O-Methyltransferase/genetics , Genes, MDR , Genetic Variation , Glucuronosyltransferase/genetics , Humans , Morphine/pharmacokinetics , Receptors, Opioid, mu/genetics
13.
Acta Anaesthesiol Scand ; 48(10): 1232-9, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15504181

ABSTRACT

BACKGROUND: Dispositions for genes encoding opioid receptors may explain some variability in morphine efficacy. Experimental studies show that morphine and morphine-6-glucuronide are less effective in individuals carrying variant alleles caused by the 118 A > G polymorphism in the mu-opioid receptor gene (OPRM1). The purpose of the study was to investigate whether this and other genetic polymorphisms in OPRM1 influence the efficacy of morphine in cancer pain patients. METHODS: We screened 207 cancer pain patients on oral morphine treatment for four frequent OPRM1 gene polymorphisms. The polymorphisms were the -172 G > T polymorphism in the 5'untranslated region of exon 1, the 118 A > G polymorphism in exon 1, and the IVS2 + 31 G > A and IVS2 + 691 G > C polymorphisms, both in intron 2. Ninety-nine patients with adequately controlled pain were included in an analysis comparing morphine doses and serum concentrations of morphine and morphine metabolites in the different genotypes for the OPRM1 polymorphisms. RESULTS: No differences related to the -172 G > T, the IVS2 + 31 G > A and the IVS2 + 691 G > C polymorphisms were observed. Patients homozygous for the variant G allele of the 118 A > G polymorphism (n = 4) needed more morphine to achieve pain control, compared to heterozygous (n = 17) and homozygous wild-type (n = 78) individuals. This difference was not explained by other factors such as duration of morphine treatment, performance status, time since diagnosis, time until death, or adverse symptoms. CONCLUSION: Patients homozygous for the 118 G allele of the mu-opioid receptor need higher morphine doses to achieve pain control. Thus, genetic variation at the gene encoding the mu-opioid receptor contributes to variability in patients' responses to morphine.


Subject(s)
Analgesics, Opioid/therapeutic use , Morphine/therapeutic use , Neoplasms/complications , Neoplasms/genetics , Pain, Intractable/drug therapy , Pain, Intractable/genetics , Receptors, Opioid, mu/genetics , Receptors, Opioid, mu/physiology , Aged , Alleles , Analgesics, Opioid/administration & dosage , Analgesics, Opioid/adverse effects , Dose-Response Relationship, Drug , Female , Genetic Testing , Genotype , Humans , Male , Middle Aged , Morphine/administration & dosage , Morphine/adverse effects , Morphine Derivatives/blood , Neoplasms/pathology , Pain Measurement/drug effects , Polymorphism, Genetic , Quality of Life , Reverse Transcriptase Polymerase Chain Reaction
14.
Pharmacogenomics J ; 3(1): 17-26, 2003.
Article in English | MEDLINE | ID: mdl-12629580

ABSTRACT

We have screened a cohort of 239 Norwegian cancer patients for sequence variation in the coding and regulatory regions of the UDP-glucuronosyltransferase 2B7 gene (UGT2B7) and analyzed the impact of gene variants on morphine glucuronidation in vivo. In all, 12 single nucleotide polymorphisms (SNPs) were identified, 10 of which have not been previously described. Only one SNP causes a change in amino acid sequence (H268Y). Seven UGT2B7 genotypes were observed and three main haplotypes predicted. There was no correlation between UGT2B7 genotype or haplotype and morphine glucuronide to morphine serum ratios among 175 patients who received chronic oral morphine therapy, and who had normal renal and hepatic function. The apparent lack of functional polymorphisms fits well with the near unimodal, but broad, distributions of the ratios (morphine 3-glucuronide/morphine: 6.4-309.2; morphine 6-glucuronide/morphine: 0.5-72.8). Our results suggest that factors other than UGT2B7 polymorphism may be more deciding for the variability in morphine glucuronide to morphine serum ratios.


Subject(s)
Genetic Variation , Glucuronides/metabolism , Glucuronosyltransferase/genetics , Morphine/metabolism , Neoplasms/genetics , Polymorphism, Single Nucleotide/genetics , Adult , Aged , Aged, 80 and over , Base Sequence , Female , Genotype , Glucuronosyltransferase/metabolism , Humans , Male , Middle Aged , Molecular Sequence Data , Neoplasms/drug therapy , Neoplasms/enzymology , Promoter Regions, Genetic , Sequence Analysis, DNA/methods , Tumor Cells, Cultured
15.
Article in English | MEDLINE | ID: mdl-11554311

ABSTRACT

The human UNG-gene at position 12q24.1 encodes nuclear (UNG2) and mitochondrial (UNG1) forms of uracil-DNA glycosylase using differentially regulated promoters, PA and PB, and alternative splicing to produce two proteins with unique N-terminal sorting sequences. PCNA and RPA co-localize with UNG2 in replication foci and interact with N-terminal sequences in UNG2. Mitochondrial UNG1 is processed to shorter forms by mitochondrial processing peptidase (MPP) and an unidentified mitochondrial protease. The common core catalytic domain in UNG1 and UNG2 contains a conserved DNA binding groove and a tight-fitting uracil-binding pocket that binds uracil only when the uracil-containing nucleotide is flipped out. Certain single amino acid substitutions in the active site of the enzyme generate DNA glycosylases that remove either thymine or cytosine. These enzymes induce cytotoxic and mutagenic abasic (AP) sites in the E. coli chromosome and were used to examine biological consequences of AP sites. It has been assumed that a major role of the UNG gene product(s) is to repair mutagenic U:G mispairs caused by cytosine deamination. However, one major role of UNG2 is to remove misincorporated dUMP residues. Thus, knockout mice deficient in Ung activity (Ung-/- mice) have only small increases in GC-->AT transition mutations, but Ung-/- cells are deficient in removal of misincorporated dUMP and accumulate approximately 2000 uracil residues per cell. We propose that BER is important both in the prevention of cancer and for preserving the integrity of germ cell DNA during evolution.


Subject(s)
DNA Glycosylases , N-Glycosyl Hydrolases/physiology , Thymine/analogs & derivatives , Animals , Apurinic Acid/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/physiology , Binding Sites , Catalytic Domain , Cell Cycle , Chromosome Mapping , Chromosomes, Human, Pair 12/genetics , DNA Repair , DNA, Mitochondrial/genetics , DNA, Mitochondrial/metabolism , Deoxyribonuclease (Pyrimidine Dimer) , Deoxyuracil Nucleotides/metabolism , Endodeoxyribonucleases/metabolism , Escherichia coli/enzymology , Escherichia coli/genetics , Gene Expression Regulation, Enzymologic , Genes , Humans , Mice , Mice, Knockout , Mitochondria/enzymology , Multigene Family , N-Glycosyl Hydrolases/chemistry , N-Glycosyl Hydrolases/genetics , Phosphorylation , Promoter Regions, Genetic , Protein Processing, Post-Translational , Protein Structure, Tertiary , Pyrimidines/metabolism , Thymine/metabolism , Uracil-DNA Glycosidase
16.
Biochem Biophys Res Commun ; 282(1): 273-7, 2001 Mar 23.
Article in English | MEDLINE | ID: mdl-11264003

ABSTRACT

The role of uncoupling protein-2 (UCP-2) in beta-cells is presently unclear. We have tested the notion that UCP-2 participates in beta-cell defense against oxidants. Expression of the UCP-2 gene in clonal beta-cells (INS-1) was decreased by 45% after 48 h of culture with vitamin E and selenite. When INS-1 cells were exposed to 200 microM H(2)O(2) for 5 min, the cell viability (MTT assay) decreased to 85 +/- 1, 61 +/- 1, 40 +/- 2, and 39 +/- 2% of control when measured respectively 30 min, 2 h, 6 h, and 16 h after H(2)O(2) exposure. At corresponding time points UCP-2 mRNA levels were 1.01 +/- 0.09, 1.53 +/- 0.15 (P < 0.05), 1.44 +/- 0.18 (P = 0.06), and 1.12 +/- 0.09 fold of control, i.e., transiently increased. We next tested whether overexpression of UCP-2 could enhance resistance of beta-cells toward H(2)O(2) toxicity. A cotransfection method using EGFP as a suitable marker and a human cDNA UCP-2 construct was used for transient overexpression of UCP-2. Transfected cells expressed the gene about 30-fold more than normal cells. After exposure to H(2)O(2) (200 micrometer, 5 min), the survival of UCP-2 overexpressing cells was measured 30-45 min later by flow cytometry. Survival was 13 +/- 0.05% higher than control (EGFP only) cells, P < 0.004 for difference. The results indicate that oxidative stress induces UCP-2 expression in beta-cells, and that UCP-2 serves a role in beta-cell defense against oxidative stress.


Subject(s)
Clone Cells/metabolism , Islets of Langerhans/metabolism , Membrane Transport Proteins , Mitochondrial Proteins , Oxidative Stress , Proteins/metabolism , Cell Survival/drug effects , Gene Expression Regulation/drug effects , Humans , Hydrogen Peroxide/pharmacology , Ion Channels , Islets of Langerhans/cytology , Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Uncoupling Protein 2 , Vitamin E/pharmacology
17.
FEBS Lett ; 476(1-2): 73-7, 2000 Jun 30.
Article in English | MEDLINE | ID: mdl-10878254

ABSTRACT

Base excision repair (BER) of DNA corrects a number of spontaneous and environmentally induced genotoxic or miscoding base lesions in a process initiated by DNA glycosylases. An AP endonuclease cleaves at the 5' side of the abasic site and the repair process is subsequently completed via either short patch repair or long patch repair, which largely require different proteins. As one example, the UNG gene encodes both nuclear (UNG2) and mitochondrial (UNG1) uracil DNA glycosylase and prevents accumulation of uracil in the genome. BER is likely to have a major role in preserving the integrity of DNA during evolution and may prevent cancer.


Subject(s)
Base Pair Mismatch , DNA Glycosylases , DNA Repair , N-Glycosyl Hydrolases/metabolism , Amino Acid Sequence , Animals , Biological Evolution , DNA Damage , Humans , Mammals , Molecular Sequence Data , N-Glycosyl Hydrolases/chemistry , Uracil-DNA Glycosidase
18.
Mutat Res ; 407(3): 227-41, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9653449

ABSTRACT

We studied the repair of cyclobutane pyrimidine dimers (CPDs) in the 5' terminal part of the transcriptionally inactive O6-methylguanine-DNA methyltransferase (MGMT) gene of MGMT-deficient human cell lines (A172, A-253 and WI-38 VA13) and in a proficient cell line (HaCaT), in which the MGMT gene was transcribed. Repair rates in the MGMT gene were compared with those in the active uracil-DNA glycosylase (UNG) and c-myc genes, and those in the repressed X-linked 754 locus and the RNA polymerase I-transcribed ribosomal gene cluster. In the active MGMT gene, there was a distinct strand specificity with more repair in the template (transcribed) strand (TS) than in the non-template strand (NTS). In contrast, no apparent strand bias in the repair of CPDs was observed in the inactive MGMT gene in the MGMT deficient cell lines, although the rates of repair varied between different cell lines. Repair in the inactive MGMT gene was consistently lower than repair in the NTSs of the expressed genes, and approached the generally poor repair of the repressed 754 locus. Whereas repair in the UNG gene was strand-specific in HaCaT, A-172 and WI-38 VA13 cells, no clear strand bias in repair of this gene was evident in A253 cells and repair was relatively inefficient. Although the repair kinetics was essentially similar in the two strands of the c-myc gene in all cell lines examined, the rate and extent of repair were in general significant, probably due to an observed transcription of both strands in the c-myc region. In conclusion, our results indicate that the relative rates of repair in inactive MGMT genes are comparable to those of repressed loci and are lower than repair rates in the NTSs of active genes, but the absolute rate of repair varies between different transformed cells.


Subject(s)
DNA Repair , O(6)-Methylguanine-DNA Methyltransferase/genetics , Pyrimidine Dimers/genetics , X Chromosome/genetics , Cell Line , Humans
19.
Chem Biol Interact ; 110(1-2): 123-36, 1998 Mar 12.
Article in English | MEDLINE | ID: mdl-9566729

ABSTRACT

We have studied the effect of low levels of paracetamol (0.3 and 1.0 mM) on gene-specific DNA repair, recovery of total RNA synthesis and cytotoxicity after exposure of human keratinocyte cells (HaCaT) to ultraviolet (UV) irradiation. Repair of cyclobutane pyrimidine dimers (CPDs) was measured in the transcriptionally active uracil-DNA glycosylase (UNG) and c-MYC loci. Repair of both strands in the UNG gene was consistently lower in the presence of paracetamol, but this reduction reached significance only at 8 h after irradiation and no dose-response was observed. For the c-MYC gene, we found no significant effect of paracetamol on the repair of CPDs, possibly because UV-irradiation is known to induce transcription of the c-MYC gene and enhanced transcription coupled repair might counteract a negative effect of paracetamol on global genome repair. A dose-dependent delay in the recovery of total RNA synthesis after UV exposure was observed in the presence of paracetamol, which also caused a 20% increase in UV-induced cytotoxicity after 24 h. Paracetamol had no significant effect on either RNA synthesis or cell survival in the absence of UV after 24 h, but reduced cell survival by approximately 10% (at 0.3 mM) and 50%, (at 1.0 mM) after 96 h exposure. Our results demonstrate that paracetamol may inhibit gene-specific repair of CPDs by affecting global genome repair and that different genes may be differentially affected.


Subject(s)
Acetaminophen/pharmacology , Analgesics, Non-Narcotic/pharmacology , DNA Glycosylases , DNA Repair/drug effects , Keratinocytes/radiation effects , N-Glycosyl Hydrolases/genetics , Ultraviolet Rays/adverse effects , Cell Survival/drug effects , Cell Survival/radiation effects , Cells, Cultured , DNA Repair/genetics , Dose-Response Relationship, Drug , Genes, myc/drug effects , Genes, myc/genetics , Humans , Keratinocytes/drug effects , Pyrimidine Dimers/metabolism , RNA/biosynthesis , Uracil-DNA Glycosidase
20.
Nucleic Acids Res ; 26(6): 1449-57, 1998 Mar 15.
Article in English | MEDLINE | ID: mdl-9490791

ABSTRACT

Promoters PA and PBin the UNG gene and alternative splicing are utilized to generate nuclear (UNG2) and mitochondrial (UNG1) forms of human uracil-DNA glycosylase. We have found the highest levels of UNG1 mRNA in skeletal muscle, heart and testis and the highest UNG2 mRNA levels in testis, placenta, colon, small intestine and thymus, all of which contain proliferating cells. In synchronized HaCaT cells mRNAs for both forms increased in late G1/early S phase, accompanied by a 4- to 5-fold increase in enzyme activity. A combination of mutational analysis and transient transfection demonstrated that an E2F-1/DP-1-Rb complex is a strong negative regulator of both promoters, whereas 'free' E2F-1/DP-1 is a weak positive regulator, although a consensus element for E2F binding is only present in PB. These results indicate a central role for an E2F-DP-1-Rb complex in cell cycle regulation of UNG proteins. Sp1 and c-Myc binding elements close to transcription start areas were positive regulators of both promoters, however, whereas overexpression in HeLa cells of Sp1 stimulated both promoters, c-Myc and c-Myc/Max overexpression had a suppressive effect. CCAAT elements were negative regulators of PB, but positive regulators of PA. These results demonstrate differential expression of mRNAs for UNG1 and UNG2 in human tissues.


Subject(s)
Carrier Proteins , Cell Nucleus/enzymology , DNA Glycosylases , DNA-Binding Proteins , Gene Expression Regulation, Enzymologic , Mitochondria/enzymology , N-Glycosyl Hydrolases/genetics , Alternative Splicing , Base Sequence , Cell Cycle , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , DNA/genetics , E2F Transcription Factors , E2F1 Transcription Factor , Female , HeLa Cells , Humans , Isoenzymes/genetics , Male , Mutagenesis, Site-Directed , Pregnancy , Promoter Regions, Genetic , RNA, Messenger/genetics , RNA, Messenger/metabolism , Retinoblastoma-Binding Protein 1 , Tissue Distribution , Transcription Factor DP1 , Transcription Factors/genetics , Transcription Factors/metabolism , Transfection , Uracil-DNA Glycosidase
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