Displaying publications 1 - 20 of 23 in total

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  1. Role of UGT1A1*6 in irinogenetics in Asians
    Kim TW, Innocenti F
    Per Med, 2007 Nov;4(4):431-434.
    PMID: 29793274 DOI: 10.2217/17410541.4.4.431
    Evaluation of: Jada SR, Lim R, Wong CI et al.: Role ofUGT1A1*6, UGT1A1*28 and ABCG2 c.421C>A polymorphisms in irinotecan-induced neutropenia in Asian cancer patients. Cancer Sci. 98(9), 1461-1467 (2007). The pharmacokinetics and toxicity of irinotecan vary widely among patients. This review focuses primarily on a study of the role of UGT1A1*6, UGT1A1*28, and ABCG2 421C>A in three Asian cancer patient populations treated with a 3-weekly regimen of irinotecan. In that study, a statistically significantly higher level of SN-38 and a relatively lower degree of glucuronidation occurred in patients with the UGT1A1*6 homozygote genotype than in patients with the reference genotype. The UGT1A1*6 allele was associated with an increased risk of severe neutropenia. In addition, the study of gene allele frequencies in three healthy Asian populations indicated that the allelic frequency of UGT1A1*6 was higher in the healthy Chinese subjects than in the Malaysian or Indian subjects. UGT1A1*28 and ABCG2 421C>A were not associated with the pharmacokinetics of SN-38 or the severity of neutropenia. In this evaluation, we put this study into the context of similar studies of irinogenetics (irinotecan pharmacogenetics) in Asians and discuss the application of UGT1A1 testing in Asian cancer patients treated with irinotecan-containing regimens.
    Matched MeSH terms: Glucuronosyltransferase
  2. Polymorphisms of UGT1A1*6, UGT1A1*27 & UGT1A1*28 in three major ethnic groups from Malaysia
    Teh LK, Hashim H, Zakaria ZA, Salleh MZ
    Indian J Med Res, 2012 Aug;136(2):249-59.
    PMID: 22960892
    Genetic polymorphisms of uridine diphosphate glucuronyltransferase 1A1 (UGT1A1) have been associated with a wide variation of responses among patients prescribed with irinotecan. Lack of this enzyme is known to be associated with a high incidence of severe toxicity. The objective of this study was to investigate the prevalence of three different variants of UGT1A1 (UGT1A1*6, UGT1A1*27 and UGT1A1*28), which are associated with reduced enzyme activity and increased irinotecan toxicity, in the three main ethnic groups in Malaysia (Malays, Chinese and Indians).
    Matched MeSH terms: Glucuronosyltransferase/blood; Glucuronosyltransferase/genetics*
  3. Fulltext Inhibition of UGT2B7 Enzyme Activity in Human and Rat Liver Microsomes by Herbal Constituents
    Abdullah NH, Ismail S
    Molecules, 2018 Oct 19;23(10).
    PMID: 30347696 DOI: 10.3390/molecules23102696
    The co-use of conventional drug and herbal medicines may lead to herb-drug interaction via modulation of drug-metabolizing enzymes (DMEs) by herbal constituents. UDP-glucuronosyltransferases (UGTs) catalyzing glucuronidation are the major metabolic enzymes of Phase II DMEs. The in vitro inhibitory effect of several herbal constituents on one of the most important UGT isoforms, UGT2B7, in human liver microsomes (HLM) and rat liver microsomes (RLM) was investigated. Zidovudine (ZDV) was used as the probe substrate to determine UGT2B7 activity. The intrinsic clearance (Vmax/Km) of ZDV in HLM is 1.65 µL/mg/min which is ten times greater than in RLM, which is 0.16 µL/mg/min. Andrographolide, kaempferol-3-rutinoside, mitragynine and zerumbone inhibited ZDV glucuronidation in HLM with IC50 values of 6.18 ± 1.27, 18.56 ± 8.62, 8.11 ± 4.48 and 4.57 ± 0.23 µM, respectively, hence, herb-drug interactions are possible if andrographolide, kaempferol-3-rutinoside, mitragynine and zerumbone are taken together with drugs that are highly metabolized by UGT2B7. Meanwhile, only mitragynine and zerumbone inhibited ZDV glucuronidation in RLM with IC50 values of 51.20 ± 5.95 μM and 8.14 ± 2.12 µM, respectively, indicating a difference between the human and rat microsomal model so caution must be exercised when extrapolating inhibitory metabolic data from rats to humans.
    Matched MeSH terms: Glucuronosyltransferase/antagonists & inhibitors*; Glucuronosyltransferase/isolation & purification; Glucuronosyltransferase/metabolism; Glucuronosyltransferase/chemistry
  4. Fulltext Prevalence of uridine glucuronosyl transferase 1A1 (UGT1A1) mutations in Malay neonates with severe jaundice
    Azlin I, Wong FL, Ezham M, Hafiza A, Ainoon O
    Malays J Pathol, 2011 Dec;33(2):95-100.
    PMID: 22299209 MyJurnal
    A number of genetic risk factors have been implicated in the development of neonatal severe hyperbilirubinaemia. This includes mutations in the uridine glucoronosyl transferase 1A1 (UGT1A1) gene which is responsible for unconjugated hyperbilirubinemia in Gilbert's Syndrome. We studied the prevalence of UGT1A1 gene mutations in a group of Malay neonates to determine whether they are risk factors to severe neonatal jaundice. One hundred and twenty-five Malay neonates with severe hyperbilirubinemia were studied. Ninety-eight infants without severe hyperbilirubinaemia were randomly selected from healthy Malay term infants (controls). DNA from EDTA cord blood samples were examined for UGT1A1 mutations nt211G > A and nt247T > C using established Taqman SNP genotyping assays and the UGT1A1*28 variant was detected by the Agilent 2100 bioanalyzer. All samples were also screened for common Malay G6PD variants using established techniques. The frequency of UGT1A1 211G > A mutation is significantly higher in the severely hyperbilirubinemic group (13%) than the control group (4%; p = 0.015) and all the positive cases were heterozygous for the mutation. There was no significant difference in the frequency of UGT1A1*28 mutation between the severely hyperbilirubinemic (3.5%) and the control group (0.01%; p = 0.09). None of the neonates in both groups carried the nt247 T > C mutation. The prevalence of G6PD mutation was significantly higher in the severely jaundiced group than control (9% vs 4%; p = 0.04). In conclusion, nt 211 G > A alleles constitute at least 12% of UGT1A1 mutations underlying unconjugated hyperbilirubinemia and appears to be a significant independent risk factor associated with severe neonatal hyperbilirubinemia in the Malay newborns.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  5. Homozygous variant of UGT1A1 gene mutation and severe neonatal hyperbilirubinemia
    Boo NY, Wong FL, Wang MK, Othman A
    Pediatr Int, 2009 Aug;51(4):488-93.
    PMID: 19674361 DOI: 10.1111/j.1442-200X.2008.02798.x
    The aim of the present study was to compare, in a case-control study, the prevalence of nucleotide 211 guanine to adenine (G-->A) mutation of uridine diphosphoglucuronosyl transferase (UGT1A1) gene in Malaysian Chinese newborns with and without severe hyperbilirubinemia (total serum bilirubin >250 micromol/L during first 48 h of life or > or =300 micromol/L thereafter), and to determine whether this mutation was a significant risk factor associated with severe hyperbilirubinemia.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  6. Frequencies of A(TA)7TAA, G71R, and G493R mutations of the UGT1A1 gene in the Malaysian population
    Yusoff S, Van Rostenberghe H, Yusoff NM, Talib NA, Ramli N, Ismail NZ, et al.
    Biol. Neonate, 2006;89(3):171-6.
    PMID: 16210851
    Gilbert syndrome is caused by defects in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene. These mutations differ among different populations and many of them have been found to be genetic risk factors for the development of neonatal jaundice.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  7. Fulltext Induction of epoxide hydrolase, glucuronosyl transferase, and sulfotransferase by phenethyl isothiocyanate in male Wistar albino rats
    Abdull Razis AF, Mohd Noor N, Konsue N
    Biomed Res Int, 2014;2014:391528.
    PMID: 24592387 DOI: 10.1155/2014/391528
    Phenethyl isothiocyanate (PEITC) is an isothiocyanate found in watercress as the glucosinolate (gluconasturtiin). The isothiocyanate is converted from the glucosinolate by intestinal microflora or when contacted with myrosinase during the chopping and mastication of the vegetable. PEITC manifested protection against chemically-induced cancers in various tissues. A potential mechanism of chemoprevention is by modulating the metabolism of carcinogens so as to promote deactivation. The principal objective of this study was to investigate in rats the effect of PEITC on carcinogen-metabolising enzyme systems such as sulfotransferase (SULT), N-acetyltransferase (NAT), glucuronosyl transferase (UDP), and epoxide hydrolase (EH) following exposure to low doses that simulate human dietary intake. Rats were fed for 2 weeks diets supplemented with PEITC at 0.06 µmol/g (low dose, i.e., dietary intake), 0.6 µmol/g (medium dose), and 6.0 µmol/g (high dose), and the enzymes were monitored in rat liver. At the Low dose, no induction of the SULT, NAT, and EH was noted, whereas UDP level was elevated. At the Medium dose, only SULT level was increased, whereas at the High dose marked increase in EH level was observed. It is concluded that PEITC modulates carcinogen-metabolising enzyme systems at doses reflecting human intake thus elucidating the mechanism of its chemoprevention.
    Matched MeSH terms: Glucuronosyltransferase/biosynthesis*
  8. Rapid detection of the UGT1A1 single nucleotide polymorphism G211A using real-time PCR with Taqman minor groove binder probes
    Wong FL, Wang MK, Boo NY, Hamidah NH, Ainoon BO
    J Clin Lab Anal, 2007;21(3):167-72.
    PMID: 17506482
    The UGT1A1 Taqman MGB probe single nucleotide polymorphism (SNP) genotyping assay was developed to detect nucleotide 211 of the UDP-glucoronocyltransferase 1A1 (UGT1A1) gene. Defects in this enzyme interfere with process of conjugation of bilirubin and cause unconjugated hyperbilirubinemia. Variation at nucleotide 211 in the coding region of the UGT1A1 gene has been shown to be prevalent in Japanese and Chinese. Using an ABI sequence detection system (SDS) 7000, an allele-specific real-time PCR-based genotyping method was established to detect nucleotide G211A. Cord blood from 125 infants without hyperbilirubinemia (controls) were compared with cord blood from 74 infants (cases) with severe hyperbilirubinemia (total serum bilirubin > 300 micromol/L). Homozygous variation of the UGT1A1 gene at nucleotide 211(A/A) is significantly more common in cases (14.9%) than in controls (0.8%) (P<0.001). Direct sequencing from 20 randomly selected samples showed eight samples with homozygous wild type, seven with homozygous variant, and five samples were heterozygous. The result from this assay was in complete concordance with the DNA sequencing result and clearly discriminate wild-type (G/G), homozygous variant (A/A), and heterozygous (G/A). This assay is rapid and robust for screening of SNP G211A to determine if this polymorphism plays a role in causing severe neonatal jaundice in the local context.
    Matched MeSH terms: Glucuronosyltransferase/blood; Glucuronosyltransferase/genetics*
  9. Genetic Factors and Delayed TSB Monitoring and Treatment as Risk Factors Associated with Severe Hyperbilirubinemia in Term Neonates Admitted for Phototherapy
    Boo NY, Sin S, Chee SC, Mohamed M, Ahluwalia AK, Ling MM, et al.
    J Trop Pediatr, 2020 12 01;66(6):569-582.
    PMID: 32577754 DOI: 10.1093/tropej/fmaa016
    OBJECTIVES: This study aimed to determine whether maternal-fetal blood group isoimmunization, breastfeeding, birth trauma, age when first total serum bilirubin (TSB) was measured, age of admission, and genetic predispositions to hemolysis [due to genetic variants of glucose-6-phosphate dehydrogenase (G6PD) enzyme], and reduced hepatic uptake and/or conjugation of serum bilirubin [due to genetic variants of solute carrier organic anion transporter protein family member 1B1 (SLCO1B1) and uridine diphosphate glucuronosyltransferase family 1 member A1 (UGT1A1)] were significant risk factors associated with severe neonatal hyperbilirubinemia (SNH, TSB ≥ 342µmol/l) in jaundiced term neonates admitted for phototherapy.

    METHODS: The inclusion criteria were normal term neonates (gestation ≥ 37 weeks). Parents/care-givers were interviewed to obtain data on demography, clinical problems, feeding practice and age when first TSB was measured. Polymerase chain reaction-restriction fragment length polymorphism method was used to detect common G6PD, UGT1A1 and SLCO1B1 variants on each neonate's dry blood specimens.

    RESULTS: Of 1121 jaundiced neonates recruited, 232 had SNH. Logistic regression analysis showed that age (in days) when first TSB was measured [adjusted odds ratio (aOR) = 1.395; 95% confidence interval (CI) 1.094-1.779], age (in days) of admission (aOR = 1.127; 95% CI 1.007-1.260) and genetic mutant UGT1A1 promoter A(TA)7TAA (aOR = 4.900; 95% CI 3.103-7.739), UGT1A1 c.686C>A (aOR = 6.095; 95% CI 1.549-23.985), SLCO1B1 c.388G>A (aOR = 1.807; 95% CI 1.242-2.629) and G6PD variants and/or abnormal G6PD screening test (aOR = 2.077; 95% CI 1.025-4.209) were significantly associated with SNH.

    CONCLUSION: Genetic predisposition, and delayed measuring first TSB and commencing phototherapy increased risk of SNH.

    Matched MeSH terms: Glucuronosyltransferase/genetics*; Glucuronosyltransferase/metabolism
  10. Neonatal buccal cell collection: a non-invasive strategy to provide a reliable source of DNA for high resolution melting analysis
    Cheung, Tian Pei, Rostenberghe, Hans Van, Narazah Mohd Yusoff, Noraida Ramli, Nor Rosidah Ibrahim, Nishio, Hisahide, et al.
    Malaysian Journal of Paediatrics and Child Health, 2019;25(2):14-22.
    MyJurnal
    Background: The low yield and quality of buccal-derived genomic DNA have reduced its applicability in various genetic research. The aim of this study was to assess the quantity, purity and genotyping efficiency of genomic DNA isolated from neonatal buccal swabs. Methods: Paired buccal swabs and whole blood samples were collected from 60 neonates with the mean age 5 days (SD=1.57). The genomic DNA quantity and purity were measured by using Infinite® 200 PRO NanoQuant reader and agarose gel electrophoresis. High-resolution melting (HRM) analysis was used to analyse the sequence variants present in uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1 c.211G>A) and nuclear receptor subfamily 1, group I, member 3 (NR1I3 IVS8+116T>G) genes. Results: Buccal swabs provided lower mean genomic DNA concentration (18.78 ± 8.39 ng/μl versus 40.02 ± 13.03 ng/μl), yield (2.63 ± 1.17 μgversus8.00 ± 2.61 μg). The purity of buccal samples however were inconsistent with 16 samples (26.7%) having A260/280 ratios below 1.8 which indicated protein contamination. Genomic DNA purity for all blood samples were within the ideal range with average absorbance ratios of 1.8−2.0. However, all buccal genomic DNA demonstrated 100% genotype call rates for all variants. A complete genotype concordance was also observed between paired genomic DNA samples. Conclusion: Despite related to a reduced quantity and purity, neonatal buccal genomic DNA could generate reliable HRM genotyping results. Therefore, buccal swab collection is a promising alternative to the invasive blood sampling to provide genomic DNA for genetic analysis involving paediatric population.
    Matched MeSH terms: Glucuronosyltransferase
  11. Risk factors associated with unconjugated neonatal hyperbilirubinemia in Malaysian neonates
    Wong F, Boo N, Othman A
    J Trop Pediatr, 2013 Aug;59(4):280-5.
    PMID: 23640907 DOI: 10.1093/tropej/fmt023
    To investigate the risk factors associated with neonatal hyperbilirubinemia in Malaysian neonates.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  12. Screening for G71R mutation of the UGT1A1 gene in the Javanese-Indonesian and Malay-Malaysian populations
    Sutomo R, Talib NA, Yusoff NM, Van Rostenberghe H, Sadewa AH, Sunarti, et al.
    Pediatr Int, 2004 Oct;46(5):565-9.
    PMID: 15491385
    There are significant differences in the prevalence and severity of neonatal jaundice among various populations. Recently, it has been reported that a mutation of the UGT1A1 gene, glycine to arginine at codon 71 (G71R), is related to the development of neonatal jaundice in East Asian populations. However, whether the G71R mutation contributes to the high incidence of neonatal jaundice in different Asian populations remains unknown. The authors screened for this mutation in the Javanese-Indonesian and Malay-Malaysian populations.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  13. Isothiocyanates and Xenobiotic Detoxification
    Abdull Razis AF, Konsue N, Ioannides C
    Mol Nutr Food Res, 2018 09;62(18):e1700916.
    PMID: 29288567 DOI: 10.1002/mnfr.201700916
    The potential of isothiocyanates to antagonize the carcinogenicity of structurally diverse chemicals has been established in animals. A feasible mechanism of action involves protecting DNA by reducing the availability of the genotoxic metabolites of chemical carcinogens by either inhibiting their generation and/or stimulating their detoxification. In vivo as well as in vitro studies conducted in rat/human primary hepatocytes and precision-cut tissue slices have revealed that isothiocyanates can impair cytochrome P450 activity, including the CYP1 family which is the most active in the bioactivation of carcinogens, by virtue of being mechanism-based inactivators. The aromatic phenethyl isothiocyanate is the most effective of those studied, whereas aliphatic isothiocyanates such as sulforaphane and erucin necessitate high doses in order to manifest such effects that may not always be achievable through the diet. In all systems studied, isothiocyanates are strong inducers of detoxification enzyme systems including quinone reductase, glutathione S-transferase, epoxide hydrolase, and UDP-glucuronosyl transferase. Indeed, in smokers phenethyl isothiocyanate intake increases the urinary excretion of inactive mercapturate metabolites of toxic chemicals present in tobacco. Glucosinolates, the precursors of isothiocyanates, have also the potential to upregulate detoxification enzyme systems, but their contribution to the cancer chemoprevention linked to cruciferous vegetable consumption remains to be evaluated.
    Matched MeSH terms: Glucuronosyltransferase/metabolism
  14. The influence of genetic polymorphisms on the efficacy and side effects of anastrozole in postmenopausal breast cancer patients
    Abubakar MB, Wei K, Gan SH
    Pharmacogenet Genomics, 2014 Dec;24(12):575-81.
    PMID: 25203739 DOI: 10.1097/FPC.0000000000000092
    Breast cancer is a common cause of cancer mortality among women. Several genetic factors have been implicated in its development. Current treatment guidelines for estrogen receptor-positive breast cancer recommend that anastrozole [or any of the other two aromatase inhibitors (letrozole and exemestane)] is used as an alternative to tamoxifen or following several years of tamoxifen treatment. Nevertheless, this approach is still associated with many challenges, ranging from the recurrence of breast cancer to considerable interindividual variability in the tolerability of anastrozole, which may cause adverse effects, such as musculoskeletal symptoms, and lead to the withdrawal of many patients from treatment. Variabilities in the genes encoding the drug target (aromatase) or its metabolizing enzymes (CYP3A and UGT1A) contribute toward the interindividual variability in anastrozole's pharmacokinetics and/or pharmacodynamics. This paper reviews the role of genetic polymorphisms of CYP19A1, CYP3A4, and UGT1A4 in the responses of female hormone receptor-positive postmenopausal breast cancer patients to anastrozole. Many reviews in the literature have suggested that the study of functional polymorphisms and investigation of relevant genetic markers may provide valuable information in predicting responses to anastrozole in terms of its therapeutic and adverse effects. Nevertheless, more studies are required before the knowledge of its pharmacogenomics can be applied to the individualization of treatment to ensure that patients receive the maximum benefits. Therefore, future analyses, including but not limited to genome-wide association studies, are encouraged to address some of the gray areas in the pharmacogenomics of anastrozole therapy in postmenopausal breast cancer cases; this will help in providing guidance for future pharmacogenomics protocols when anastrozole is utilized in patients' management.
    Matched MeSH terms: Glucuronosyltransferase/genetics*
  15. The effect of various drugs on the glucuronidation of zidovudine (azidothymidine; AZT) by human liver microsomes
    Sim SM, Back DJ, Breckenridge AM
    Br J Clin Pharmacol, 1991 Jul;32(1):17-21.
    PMID: 1909542
    1. Zidovudine (3'-azido-3'-deoxythymidine; AZT) is the drug of proven efficacy available for the treatment of patients with AIDS or ARC. It is eliminated mainly by hepatic glucuronidation. Therefore, interference with this metabolic pathway may lead to enhancement of AZT effect or to increased toxicity of the drug. We have examined the effect of a number of drugs which themselves undergo glucuronidation on AZT conjugation by human liver microsomes in vitro. 2. AZT glucuronidation followed Michaelis-Menten kinetics. The apparent Km and Vmax values (mean +/- s.d., n = 5), were 2.60 +/- 0.52 mM and 68.0 +/- 23.4 nmol h-1 mg-1, respectively, as determined from Eadie-Hofstee plots. 3. Dideoxyinosine, sulphanilamide and paracetamol were essentially non-inhibitory at concentrations up to 10 mM (4 times the concentration of AZT in the incubation). The most marked inhibitory effects were seen with indomethacin, naproxen, chloramphenicol, probenecid and ethinyloestradiol, with enzyme activity decreased by 97.7, 94.9, 88.7, 83.4% and 79.0%, respectively, at a concentration of 10 mM. Other compounds producing some inhibition of AZT conjugation were oxazepam, salicylic acid and acetylsalicylic acid. 4. Further studies are necessary to characterise the inhibition observed but the method described enables a screen of potentially important drug interactions to be carried out.
    Matched MeSH terms: Glucuronosyltransferase/metabolism*
  16. Effect of tocotrienols on hepatocarcinogenesis induced by 2-acetylaminofluorene in rats
    Ngah WZ, Jarien Z, San MM, Marzuki A, Top GM, Shamaan NA, et al.
    Am J Clin Nutr, 1991 04;53(4 Suppl):1076S-1081S.
    PMID: 1672785 DOI: 10.1093/ajcn/53.4.1076S
    The effects of tocotrienols on hepatocarcinogenesis in rats fed with 2-acetylaminofluorene (AAF) were followed morphologically and histologically for a period of 20 wk. No differences between treated and control rats in the morphology and histology of their livers was observed. Cell damage was extensive in the livers of AAF-treated rats but less extensive in the AAF-tocotrienols-treated rats when compared with normal and tocotrienols-treated rats. 2-Acetylaminofluorene significantly increases the activities of both plasma and liver microsomal gamma-glutamyltranspeptidase (GGT) and liver microsomal UDP-glucuronyltransferase (UDP-GT). Tocotrienols administered together with AAF significantly decrease the activities of plasma GGT after 12 and 20 wk (P less than 0.01, P less than 0.002, respectively) and liver microsomal UDP-GT after 20 wk (P less than 0.02) when compared with the controls and with rats treated only with tocotrienols. Liver microsomal GGT also showed a similar pattern to liver microsomal UDP-GT but the decrease was not significant. These results suggest that tocotrienols administered to AAF-treated rats reduce the severity of hepatocarcinogenesis.
    Matched MeSH terms: Glucuronosyltransferase/blood
  17. Role of UGT1A1*6, UGT1A1*28 and ABCG2 c.421C>A polymorphisms in irinotecan-induced neutropenia in Asian cancer patients
    Jada SR, Lim R, Wong CI, Shu X, Lee SC, Zhou Q, et al.
    Cancer Sci, 2007 Sep;98(9):1461-7.
    PMID: 17627617
    The objectives of the present study were (i) to study the pharmacogenetics of UGT1A1*6, UGT1A1*28 and ABCG2 c.421C>A in three distinct healthy Asian populations (Chinese, Malays and Indians), and (ii) to investigate the polygenic influence of these polymorphic variants in irinotecan-induced neutropenia in Asian cancer patients. Pharmacokinetic and pharmacogenetic analyses were done after administration of irinotecan as a 90-min intravenous infusion of 375 mg/m(2) once every 3 weeks (n = 45). Genotypic-phenotypic correlates showed a non-significant influence of UGT1A1*28 and ABCG2 c.421C>A polymorphisms on the pharmacokinetics of SN-38 (P > 0.05), as well as severity of neutropenia (P > 0.05). Significantly higher exposure levels to SN-38 (P = 0.018), lower relative extent of glucuronidation (REG; P = 0.006) and higher biliary index (BI; P = 0.003) were found in cancer patients homozygous for the UGT1A1*6 allele compared with patients harboring the reference genotype. The mean absolute neutrophil count (ANC) was 85% lower and the prevalence of grade 4 neutropenia (ANC < or = 500/microL) was 27% in patients homozygous for UGT1A1*6 compared with the reference group. Furthermore, the presence of the UGT1A1*6 allele was associated with an approximately 3-fold increased risk of developing severe grade 4 neutropenia compared with patients harboring the reference genotype. These exploratory findings suggest that homozygosity for UGT1A1*6 allele may be associated with altered SN-38 disposition and may increase the risk of severe neutropenia in Asian cancer patients, particularly in the Chinese cancer patients who comprised 80% (n = 36) of the patient population in the present study.
    Matched MeSH terms: Glucuronosyltransferase/genetics*; Glucuronosyltransferase/physiology
  18. Fulltext Gallic acid attenuates dextran sulfate sodium-induced experimental colitis in BALB/c mice
    Pandurangan AK, Mohebali N, Norhaizan ME, Looi CY
    Drug Des Devel Ther, 2015;9:3923-34.
    PMID: 26251571 DOI: 10.2147/DDDT.S86345
    Gallic acid (GA) is a polyhydroxy phenolic compound that has been detected in various natural products, such as green tea, strawberries, grapes, bananas, and many other fruits. In inflammatory bowel disease, inflammation is promoted by oxidative stress. GA is a strong antioxidant; thus, we evaluated the cytoprotective and anti-inflammatory role of GA in a dextran sulfate sodium (DSS)-induced mouse colitis model. Experimental acute colitis was induced in male BALB/c mice by administering 2.5% DSS in the drinking water for 7 days. The disease activity index; colon weight/length ratio; histopathological analysis; mRNA expressions of IL-21 and IL-23; and protein expression of nuclear erythroid 2-related factor 2 (Nrf2) were compared between the control and experimental mice. The colonic content of malondialdehyde and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity were examined as parameters of the redox state. We determined that GA significantly attenuated the disease activity index and colon shortening, and reduced the histopathological evidence of injury. GA also significantly (P<0.05) reduced the expressions of IL-21 and IL-23. Furthermore, GA activates/upregulates the expression of Nrf2 and its downstream targets, including UDP-GT and NQO1, in DSS-induced mice. The findings of this study demonstrate the protective effect of GA on experimental colitis, which is probably due to an antioxidant nature of GA.
    Matched MeSH terms: Glucuronosyltransferase/genetics; Glucuronosyltransferase/metabolism
  19. Copy number polymorphisms in new HapMap III and Singapore populations
    Ku CS, Teo SM, Naidoo N, Sim X, Teo YY, Pawitan Y, et al.
    J Hum Genet, 2011 Aug;56(8):552-60.
    PMID: 21677662 DOI: 10.1038/jhg.2011.54
    Copy number variations can be identified using newer genotyping arrays with higher single nucleotide polymorphisms (SNPs) density and copy number probes accompanied by newer algorithms. McCarroll et al. (2008) applied these to the HapMap II samples and identified 1316 copy number polymorphisms (CNPs). In our study, we applied the same approach to 859 samples from three Singapore populations and seven HapMap III populations. Approximately 50% of the 1291 autosomal CNPs were found to be polymorphic only in populations of non-African ancestry. Pairwise comparisons among the 10 populations showed substantial differences in the CNPs frequencies. Additionally, 698 CNPs showed significant differences with false discovery rate (FDR)<0.01 among the 10 populations and these loci overlap with known disease-associated or pharmacogenetic-related genes such as CFHR3 and CFHR1 (age related macular degeneration), GSTTI (metabolism of various carcinogenic compounds and cancers) and UGT2B17 (prostate cancer and graft-versus-host disease). The correlations between CNPs and genome-wide association studies-SNPs were investigated and several loci, which were previously unreported, that may potentially be implicated in complex diseases and traits were found; for example, childhood acute lymphoblastic leukaemia, age-related macular degeneration, breast cancer, response to antipsychotic treatment, rheumatoid arthritis and type-1 diabetes. Additionally, we also found 5014 novel copy number loci that have not been reported previously by McCarroll et al. (2008) in the 10 populations.
    Matched MeSH terms: Glucuronosyltransferase/genetics
  20. The Implication of the Polymorphisms of COX-1, UGT1A6, and CYP2C9 among Cardiovascular Disease (CVD) Patients Treated with Aspirin
    Jalil NJ, Bannur Z, Derahman A, Maskon O, Darinah N, Hamidi H, et al.
    J Pharm Pharm Sci, 2015;18(3):474-83.
    PMID: 26517138
    PURPOSE:   Enzymes potentially responsible for the pharmacokinetic variations of aspirin include cyclooxygenase-1 (COX-1), UDP-glucuronosyltransferase (UGT1A6) and P450 (CYP) (CYP2C9). We therefore aimed to determine the types and frequencies of variants of COX-1 (A-842G), UGT1A6 (UGT1A6*2; A541G and UGT1A6*3; A522C) and CYP2C9 (CYP2C9*3; A1075C) in the three major ethnic groups in Malaysia. In addition, the role of these polymorphisms on aspirin-induced gastritis among the patients was investigated.

    METHODS: A total of 165 patients with cardiovascular disease who were treated with 75-150 mg daily dose of aspirin and 300 healthy volunteers were recruited. DNA was extracted from the blood samples and genotyped for COX-1 (A-842G), UGT1A6 (UGT1A6*2 and UGT1A6*3) and CYP2C9 (CYP2C9*3; A1075C) using allele specific polymerase chain reaction (AS-PCR).

    RESULTS: Variants UGT1A6*2,*3 and CYP2C9*3 were detected in relatively high percentage of 22.83%, 30.0% and 6.50%, respectively; while COX-1 (A-842G) was absent. The genotype frequencies for UGT1A6*2 and *3 were significantly different between Indians and Malays or Chinese. The level of bilirubin among patients with different genotypes of UGT1A6 was significantly different (p-value < 0.05). In addition, CYP2C9*3 was found to be associated with gastritis with an odd ratio of 6.8 (95 % Cl OR: 1.39 - 33.19; P = 0.033).

    CONCLUSION: Screening of patients with defective genetic variants of UGT1A6 and CYP2C9*3 helps in identifying patients at risk of aspirin induced gastritis. However, a randomised clinical study of bigger sample size would be needed before it is translated to clinical use.

    Matched MeSH terms: Glucuronosyltransferase/genetics*
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