The correlation of UGT1A1 gene polymorphism and unexplained neonatal hyperbilirubinemia in Dai ethnic group of Yunnan Province / 中国新生儿科杂志

Objective:To study the correlation of uridine diphosphate glucuronosyl transferase 1A1(UGT1A1) gene polymorphism and neonatal hyperbilirubinemia among Dai ethnic group in Yunnan province.Methods:From January 2020 to December 2022, Dai neonates with unexplained neonatal hyperbilirubinemia admitted to three hospitals in Yunnan Province were prospectively enrolled into the hyperbilirubinemia group. Neonates hospitalized during the same period without hyperbilirubinemia were selected as the control group. The serum total bilirubin levels were measured and UGT1A1 gene sequencing was performed in all neonates. The differences of genotype frequency and allele frequency of UGT1A1 gene in the two groups were analyzed. Logistic regression analysis was used to analyze the effects of each mutation on hyperbilirubinemia among Dai neonates.Results:A total of 92 neonates were in the hyperbilirubinemia group and 86 in the control group. No significant differences existed between the two groups on following items: gender, age at admission, gestational age (GA), birth weight (BW), feeding pattern, white blood cell count (WBC) and hemoglobin level ( P>0.05).Three mutation loci were detected in the hyperbilirubinemia group (c.211G>A, c.1091C>T and c.1456T>G), with frequencies 45.7%, 3.3% and 2.2%, respectively. Two mutation loci were detected in the control group (c.211G>A and c.1091C>T), with frequencies 17.4% and 1.2%. Correlation analysis showed that c.211G>A frequency (45.7%) and A allele frequency (23.9%) in the hyperbilirubinemia group were significantly higher than the control group ( P<0.05). No significant differences existed in the frequencies of c.1091C>T and c.1456T>G between the two groups ( P>0.05). Logistic regression analysis showed that c.211G>A was risk factor of unexplained neonatal hyperbilirubinemia in Dai neonates ( OR=3.976, 95% CI 1.991-7.941). Conclusions:The most common mutation of UGT1A1 gene in Chinese Dai neonates with unexplained neonatal hyperbilirubinemia in Yunnan Province is c.211G>A, which increases the risk of hyperbilirubinemia.

Acute pancreatitis and severe hyperbilirubinemia as initial presentation of Gilbert syndrome

Gilbert syndrome (GS) is benign, often familial condition characterized by recurrent but asymptomatic mild unconjugated hyperbilirubinemia in the absence of hemolysis or underlying liver disease. The coexistence of GS with other more clinically significant conditions could interfere with their diagnoses. The genetic variation described as GS may affect drug glucuronidation and could potentially precipitate. Gallstones are the commonest ailment affecting the hepato-biliary system. Associated jaundice is usually direct, commonly due to biliary obstructive lesions. Unconjugated hyperbilirubinemia with cholelithiasis is commonly seen with hemolytic disease. In the absence of hemolysis or systemic causes, congenital causes prevail, commonest of which is Gilbert’ Syndrome. Here we report a case of 21-year old male who presented to our hospital with complaint of pain abdomen and was diagnosed as gall stone induced pancreatitis which was further diagnosed as GS after genetic testing for UGT1A1 gene polymorphism.

Combined effect of PNPLA3 rs738409 and UGT1A1 rs10929303 gene polymorphisms on nonalcoholic fatty liver disease in children / 中华肝脏病杂志

Objective: To investigate the combined effects of patatin-like phospholipase domain containing 3 (PNPLA3) rs738409 (C > G) and uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) rs10929303 (C > T) on nonalcoholic fatty liver disease (NAFLD) in children and adolescents so as to provide scientific evidence for NAFLD genetic research. Methods: 1 027 children and adolescents aged 7-18 were selected as the research subjects. The general situation, past medical history, height and body weight measurements, and B- mode ultrasound test of the liver were investigated by dedicated full-time personnel. In addition, the morning fasting venous blood was collected to measure the blood biochemical indicators. DNA was extracted and genotyped for PNPLA3 rs738409 and UGT1A1 rs10929303. Logistic regression analysis was used to analyze the association and combined effect of the two gene polymorphisms and NAFLD. Statistical analysis was performed by t-test, Mann-Whitney U test, or c2 test according to different data. Results: The GG genotype of PNPLA3 rs738409 and the CC genotype of UGT1A1 rs10929303 were associated with an increased risk of developing NAFLD in children by 89% (OR = 1.89, 95% CI: 1.11-3.23, P = 0.019) and 96% (OR = 1.96, 95% CI: 1.21-3.17, P = 0.006), respectively, while the concurrent risk of NAFLD in those who carried the above two genotypes increased by 306% compared with those who did not carry both genotypes (OR = 4.06, 95% CI: 1.90 ~ 8.66, P < 0.001). Conclusion: The combined effect of PNPLA3 and UGT1A1 gene polymorphisms can significantly increase the risk of NAFLD in children, providing new evidence for elucidating the genetic susceptibility to NAFLD.

Association of UGT1A1 gene G71R polymorphism with neonatal hyperbilirubinemia / 中国小儿急救医学

Objective:To explore the association between the G71R polymorphism of the UGT1A1 gene and neonatal hyperbilirubinemia. Methods:DNA was extracted from blood samples of 61 neonates with severe neonatal hyperbilirubinemia(severe neonatal hyperbilirubinemia group), 60 neonates with hyperbilirubinemia(hyperbilirubinemia group) and 62 healthy neonates(control group), the G71R mutation of UGT1A1 gene was analyzed by direct sequencing. Results:In severe neonatal hyperbilirubinemia group, there were 17 cases of homozygous mutation(A/A), 23 cases of heterozygous mutation(A/G) , and 21 cases of wild type(G/G) , with 28.87% homozygous mutation rate and 37.70% heterozygous mutation rate.In neonatal hyperbilirubinemia group, there were ten cases of homozygous mutation(A/A), 28 cases of heterozygous mutation(A/G) and 22 cases of wild type(G/G), with 16.67% homozygous mutation rate and 46.67% heterozygous mutation rate.In the control group, there were nine cases of homozygous mutation (A/A), 28 cases of heterozygous mutation(A/G) and 25 cases of wild type(G/G), among which the homozygous mutation rate was 14.52% and the heterozygous mutation rate was 45.16%.The genotype frequency( χ2=4.14, P=0.38)and allele frequency( χ2=2.47, P=0.29)of G71R in severe neonatal hyperbilirubinemia group, neonatal hyperbilirubinemia group and control group were not statistically significant. Conclusion:The G71R polymorphism of the UGT1A1 gene may not be significantly correlated with the prevalence of neonatal hyperbilirubinemia.

Characteristics and Clinical Implication of UGT1A1 Heterozygous Mutation in Tumor / 中国肺癌杂志

BACKGROUND@#The literature recommends that reduced dosage of CPT-11 should be applied in patients with UGT1A1 homozygous mutations, but the impact of UGT1A1 heterozygous mutations on the adverse reactions of CPT-11 is still not fully clear.@*METHODS@#A total of 107 patients with UGT1A1 heterozygous mutation or wild-type, who were treated with CPT-11 from January 2018 to September 2021 in Peking University Third Hospital, were retrospectively enrolled. The adverse reaction spectra of patients with UGT1A1*6 and UGT1A1*28 mutations were analyzed. Adverse reactions were evaluated according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) 5.0. The efficacy was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. The genotypes of UGT1A1*6 and UGT1A1*28 were detected by digital fluorescence molecular hybridization.@*RESULTS@#There were 43 patients with UGT1A1*6 heterozygous mutation, 26 patients with UGT1A1*28 heterozygous mutation, 8 patients with UGT1A1*6 and UGT1A1*28 double heterozygous mutations, 61 patients with heterozygous mutation at any gene locus of UGT1A1*6 and UGT1A1*28. Logistic regression analysis showed that the presence or absence of vomiting (P=0.013) and mucositis (P=0.005) was significantly correlated with heterozygous mutation of UGT1A1*28, and the severity of vomiting (P<0.001) and neutropenia (P=0.021) were significantly correlated with heterozygous mutation of UGT1A1*6. In colorectal cancer, UGT1A1*6 was significantly correlated to diarrhea (P=0.005), and the other adverse reactions spectrum was similar to that of the whole patient cohort, and efficacy and prognosis were similar between patients with different genotypes and patients treated with reduced CPT-11 dosage or not.@*CONCLUSIONS@#In clinical use, heterozygous mutations of UGT1A1*6 and UGT1A1*28 are related to the risk and severity of vomiting, diarrhea, neutropenia and mucositis in patients with Pan-tumor and colorectal cancer post CPT-11 therpy. In colorectal cancer, UGT1A1*6 is significantly related to diarrhea post CPT-11 use, efficacy and prognosis is not affected by various genotypes or CPT-11 dosage reduction.

UGT1A1 gene mutations in Chinese Dong neonates in Sanjiang, Guangxi / 中国当代儿科杂志

OBJECTIVES@#To study the characteristics of UGT1A1 gene mutations in Dong neonates in Sanjiang County of Liuzhou and its association with the pathogenesis of hyperbilirubinemia in Dong neonates.@*METHODS@#A prospective analysis was performed on 84 neonates who were diagnosed with unexplained hyperbilirubinemia in the Department of Neonatology, Sanjiang County People's Hospital, from January 2021 to January 2022. Sixty healthy neonates born during the same period were enrolled as the control group. Peripheral blood genomic DNA was extracted for both groups, and UGT1A1 exon 1 was amplified by PCR and sequenced.@*RESULTS@#In the case group, 33 neonates were found to have G71R missense mutation, with a mutation rate of 39%. The case group had a significantly higher frequency of A allele than the healthy control group (21% vs 10%, P<0.05). The risk of hyperbilirubinemia in Dong neonates carrying G71R missense mutation was 2.588 times as high as that in healthy neonates carrying wild-type UGT1A1 gene (P<0.05). Hardy-Weinberg equilibrium testing showed that the UGT1A1 G71R locus was in genetic equilibrium in both groups (P>0.05).@*CONCLUSIONS@#UGT1A1 G71R mutation is a high-frequency gene mutation type in Dong neonates in Sanjiang County, and G71R missense mutation is associated with hyperbilirubinemia in Dong neonates.

Association of UGT1A6 gene polymorphism with clinical outcome in pediatric epileptic patients on sodium valproate monotherapy

Pediatric epilepsy comprises chronic neurological disorders characterized by recurrent seizures. Sodium valproate is one of the common antiseizure medications used for treatment. Glucuronide conjugation is the major metabolic pathway of sodium valproate, carried out by the enzyme uridine 5′-diphosphate (UDP) glucuronosyl transferase (UGT) whose gene polymorphisms may alter the clinical outcome. The objective of this study was to assess the association between UGT1A6 genetic polymorphism and clinical outcome in terms of efficacy and tolerability in pediatric epileptic patients on sodium valproate monotherapy. Pediatric epileptic patients (n=65) aged 2-18 years receiving sodium valproate monotherapy for the past one month were included. Genetic polymorphism patterns of UGT1A6 (T19G, A541G, A552C) were evaluated by PCR-RFLP. Clinical outcome was seizure control during the 6 months observation period. Tolerability was measured by estimating the hepatic, renal, and other lab parameters. Out of 65 patients, TT (40%), TG (57%), and GG (3%) patterns were observed in UGT1A6 (T19G) gene, AA (51%), AG (40%), and GG (9%) in (A541G) gene, and AA (43%), AC (43%), and CC (14%) in (A552C) gene. No statistical difference in clinical outcome was found for different UGT1A6 genetic polymorphism patterns. We concluded that different patterns of UGT1A6 genetic polymorphism were not associated with the clinical outcome of sodium valproate in terms of efficacy and tolerability. Sodium valproate was well-tolerated among pediatric patients with epilepsy and can be used as an effective antiseizure medication.

Prevalence of UGT1A1 (TA)n promoter polymorphism in Panamanians neonates with G6PD deficiency

A relationship between the polymorphism in promoter region of the UGT1A1 gene and the development of jaundice has been demonstrated recently. This polymorphism leads to 30% of normal rate transcription initiation of UGT1A1 gene, thus decreasing the bilirubin glucuronidation. The combination of the G6PD deficiency and polymorphism in neonates and adults may cause pronounced hyperbilirubinaemias. The aim of this study was to analyse the variations in the UGT1A1 gene promoter in Panamanians neonates with G6PD deficiency and its association with neonatal jaundice (NJ). We identified five different genotypes of TA repeats, in 17 neonates (42.5%) the normal variant TA6/TA6 and in the other 57.5% of the subjects: TA7/TA7 (12.5%), TA6/TA7 (40%), TA6/ TA8 (2.5%) and TA6/TA5 (2.5%). Additionally 75% of the 16 newborns that showed NJ had an abnormal variant in the promoter sequence, although, there was no significant difference (P = 0.068). The risk of jaundice in neonates with TA7 variant was thrice higher in subjects than with other alleles (P = 0.093, CI: 0.81–11.67). The TA7 allele frequency in this study (0.325) was consistent with the global frequency and similar to Caucasians. The results proved that there is no significant relationship between promoter polymorphism in UGT1A1 and NJ in G6PD deficient Panamanian newborns. Further studies with a greater number of subjects would determine the exact relationship between marked NJ and UGT1A promoter variations.

Research on Therapeutic Mechanism of Canhuang Tablets on Jaundiced Rats Induced by ANIT / 中国实验方剂学杂志

Objective:To explore the therapeutic mechanism of Canhuang tablets on the mRNA and protein expression of farnesoid X receptor (FXR), uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and multidrug resistance associated protein 2 (MRP2) in the liver of jaundiced rats induced by α-naphthalene isothiocyanate (ANIT). Method:The rats were divided into normal group, model group, Canhuang tablets (CHP) group and ursodeoxycholic acid tablets (UDCA) group. The jaundice model was reproduced by ANIT. After the intervention of the corresponding drugs, the contents of total bilirubin (TBIL), total bile acid (TBA), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and the liver histopathology were examined to evaluate the therapeutic effect of CHP. The relative mRNA and protein expressions of FXR, UGT1A1 and MRP2 in rat liver tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Result:CHP can significantly reduce the increase of TBIL, TBA, ALT, AST and ALP caused by ANIT in rat serum, and inhibit the liver pathological changes, which showed that the removing jaundice effect of CHP was better than UDCA. Compared with the normal group, ANIT significantly inhibited the mRNA levels of FXR, UGT1A1 and MRP2 in rat liver tissues after modeling (P<0.01). Compared with the model group, CHP and UDCA significantly increased the mRNA levels of target genes of each protein after intervention (P<0.01), and CHP was superior to UDCA in improving the mRNA level of bilirubin metabolizing enzyme UGT1A1 (P<0.01). In the aspect of affecting protein expression, compared with the normal group, ANIT modeling significantly increased the expression of FXR in rats (P<0.05). CHP intervention showed a tendency to promote the expression of FXR, while UDCA did not, but there was no significant difference between them. In the aspects of promoting bilirubin metabolism and bile excretion, the expressions of UGT1A1 and MRP2 were significantly decreased by ANIT modeling (P<0.01), while the expressions of UGT1A1 and MRP2 proteins were significantly increased after treatment of CHP (P<0.01). CHP was superior to UDCA in increasing the expression of bilirubin and bile acid efflux protein MRP2 (P<0.01). Conclusion:The jaundice abating mechanism of CHP is related to activating FXR mRNA expression in liver, promoting the mRNA and protein expression of bilirubin metabolizing enzyme UGT1A1 and bile acid transporter MRP2, improving liver metabolism of free bilirubin and promoting bile acid excretion from the liver, and alleviating cholestatic liver injury.

Effect of Polyethylene Glycol 400 on Bile Excretion of Baicalin and Its Main Metabolite / 中国实验方剂学杂志

Objective::To investigate the effect of polyethylene glycol 400 (PEG400) on rat bile excretion of baicalin and its main metabolite [baicalein 6-O-β-D-glucuronide (B6G)], and to analyze its mechanism of action. Method::Rats were randomly divided into baicalin+ water group and baicalin+ PEG400 group, the anesthesia was induced by intraperitoneal injection of 10% chloral hydrate (dose of 4 mL·kg-1) to prepare a rat bile duct intubation model. After the rats were fully awake, rats were given baicalin aqueous solution and baicalin PEG400 solution with dose of 168 mg·kg-1 for baicalin, respectively. And bile was collected from 0 h to 12 h after administration. UPLC-MS/MS was used to determine the concentration of drug excreted through bile at different time periods. Thermo Hypersil GOLD C18 column was used with acetonitrile (A)-0.1% formic acid solution (B) as the mobile phase for gradient elution (0-9 min, 90%-27%B; 9-10 min, 27%-90%B; 10-12 min, 90%B), the flow rate was 0.3 mL·min-1, the column temperature was 30 ℃, the injection volume was 5 μL. The mass spectra were obtained in positive ion mode with electrospray ionization (ESI). The effects of PEG400 on the activities and expressions in rat liver of uridine diphosphate glucuronyltransferase (UGT) 1A8 and UGT1A9 were studied in vitro incubation assay and enzyme linked immunosorbent assay (ELISA). Result::Compared with the baicalin+ water group, in the baicalin+ PEG400 group, the bile cumulative excretions of baicalin and B6G increased by 1.8 times and 2.1 times within 12 h, respectively. PEG400 increased the enzyme activities of UGT1A8 and UGT1A9 by 2.0 times and 1.5 times, and their concentrations in liver were increased by 2.2 times and 1.3 times, respectively. Conclusion::PEG400 can significantly increase the bile excretion of baicalin and its main metabolite B6G by enhancing the activities and expressions of UGT1A8 and UGT1A9, and its promoting effect on bile excretion of B6G is greater than that of baicalin, which provides a basis for the rational clinical application of PEG400 and the design of new dosage forms of flavonoids such as baicalin.

An ultra-sensitive and easy-to-use assay for sensing human UGT1A1 activities in biological systems / 药物分析学报

The human UDP-glucuronosyltransferase 1A1 (UGT1A1), one of the most essential conjugative enzymes, is responsible for the metabolism and detoxification of bilirubin and other endogenous substances, as well as many different xenobiotic compounds. Deciphering UGT1A1 relevance to human diseases and characterizing the effects of small molecules on the activities of UGT1A1 requires reliable tools for probing the function of this key enzyme in complex biological matrices. Herein, an easy-to-use assay for highly-selective and sensitive monitoring of UGT1A1 activities in various biological matrices, using liquid chromatography with fluorescence detection (LC-FD), has been developed and validated. The newly developed LC-FD based assay has been confirmed in terms of sensitivity, specificity, precision, quanti-tative linear range and stability. One of its main advantages is lowering the limits of detection and quantification by about 100-fold in comparison to the previous assay that used the same probe substrate, enabling reliable quantification of lower amounts of active enzyme than any other method. The precision test demonstrated that both intra- and inter-day variations for this assay were less than 5.5％. Further-more, the newly developed assay has also been successfully used to screen and characterize the regu-latory effects of small molecules on the expression level of UGT1A1 in living cells. Overall, an easy-to-use LC-FD based assay has been developed for ultra-sensitive UGT1A1 activities measurements in various biological systems, providing an inexpensive and practical approach for exploring the role of UGT1A1 in human diseases, interactions with xenobiotics, and characterization modulatory effects of small mole-cules on this conjugative enzyme.

Study on potential hepatotoxicity of rhein in Rhei Radix et Rhizoma based on liver metabolism / 中国中药杂志

The bilirubin metabolism mediated by the phase Ⅱ metabolizing enzyme UGT1A1 in the liver was evaluated to study the potential hepatotoxicity risk based on investigation on the inhibitory effect of rhein and its metabolites on the UGT1A1 enzyme in Rhei Radix et Rhizoma. Firstly, in vitro liver microsomes incubation was used to initiate the phase Ⅱ metabolic reaction to investigate the inhibitory effect of rheinon UGT1A1 enzyme. Secondly, the phase Ⅰ and phase Ⅱ metabolic reactions were initiated to investigate the hepatotoxicity risk of rhein metabolites. It was found that the rhein and its phase Ⅱ metabolites had no significant inhibitory effect on UGT1A1 enzyme, but its phase Ⅰ metabolites significantly reduced UGT1A1 enzyme activity. Based on the metabolites analysis, it is speculated that the rhein phase Ⅰ metabolite rheinhydroxylate and its tautomers have certain hepatotoxicity risks, while the toxicity risk induced by the prototype and phase Ⅱ metabolites of rheinglucoside, rheinglucuronic acid and rhein sulfate is small.

Prediction of potential drug interactions of apigenin based on molecular docking and in vitro inhibition experiments / 中国中药杂志

The purpose of this study was to investigate the effect of apigenin on UGT1 A1 enzyme activity and to predict the potential drug-drug interaction of apigenin in clinical use. First,on the basis of previous experiments,the binding targets and binding strength of apigenin to UGT1 A1 enzyme were predicted by computer molecular docking method. Then the inhibitory effect of apigenin on UGT1 A1 enzyme was evaluated by in vitro human liver microsomal incubation system. Molecular docking results showed that apigenin was docked into the active region of UGT1 A1 enzyme protein F,consistent with the active region of bilirubin docking,with moderate affinity. Apigenin flavone mother nucleus mainly interacted with amino acid residues ILE343 and VAL345 to form hydrophobic binding Pi-Alkyl. At the same time,the hydroxyl group on the mother nucleus and the amino acid residue LYS346 formed an additional hydrogen bond,which increased the binding of the molecule to the protein. These results suggested that the flavonoid mother nucleus structure had a special structure binding to the enzyme protein UGT1 A1,and the introduction of hydroxyl groups into the mother nucleus can increase the binding ability. In vitro inhibition experiments showed that apigenin had a moderate inhibitory effect on UGT1 A1 enzyme in a way of competitive inhibition,which was consistent with the results of molecular docking. The results of two experiments showed that apigenin was the substrate of UGT1 A1 enzyme,which could inhibit the activity of UGT1 A1 enzyme competitively,and there was a risk of drug interaction between apigenin and UGT1 A1 enzyme substrate in clinical use.

Association analysis of the UGT1A1 polymorphism and unexplained neonatal hyperbilirubinemia / 中国新生儿科杂志

Objective To study the relationship between uridine diphosphate glucuronic acid (UGT1A1) gene polymorphism and unexplained neonatal unconjugated hyperbilirubinemia in Jinhua.Method Full-term infants with unidentified non-binding hyperbilirubinemia were selected as hyperbilirubinemia group from January 2016 to December 2017 in the obstetrics or neonatal intensive care unit of Jinhua Central Hospital,healthy full-term neonates and those with physiological jaundice admitted during the same period were selected as control group.Whole blood DNA was extracted and UGT1A1 was sequenced and then annotated with human gene mutation database.The distribution and frequency of UGT1A1 genotype were analyzed.The correlation between different genotypes and unexplained unconjugated hyperbilirubinemia in neonates was also studied.Result Two hundred and forty cases were enrolled in the hyperbilirubinemia group,and 216 cases were enrolled in the control group.Four single nucleotide variation (SNV) sites associated with the disease were found on UGT1A1,which were c.211G＞A (Gly71Arg),c.686C＞A (Pro229Gln),c.1091C＞T (Pro364Leu) and c.1456T＞G (Tyr486Asp),accounting for 83.9％(141/168),1.8％(3/168),8.9％(15/168) and 5.4％(9/168) in the experimental group respectively.The genotype frequency and allele frequency analysis showed that the distribution of the two SNV sites of c.211G＞A and c.1456T＞G were statistically different between the experimental group and the control group (P＜0.05),whereas there was no statistical difference of the other two SNV sites of c.686C＞A and c.1091C＞T between the two groups.Binary Logistic regression analysis showed that c.211G＞A and c.1456T＞G were related to the occurrence of unexplained hyperbilirubinemia,The OR values (95％CI) were 5.412 (3.567～ 8.212) and 8.377 (1.052～66.670) respectively,but no correlation was found of the other two polymorphic loci.At the different genotypes of c.211G＞A locus,the levels of total bilirubin and non-binding bilirubin in infants with homozygous mutant (AA) were higher than those in infants with heterozygous mutant (GA) and wild type (GG),which was statistically significant (P＜0.05).Conclusion The most common mutation site of the UGT1A1 gene in Jinhua is c.211G＞A.The mutations of c.211G＞A and c.1456T＞G are risk factors forunconjugated hyperbilirubinemia in neonates.Of the different genotypes of c.211G＞A locus,the serum bilirubin level of homozygous mutant group was significantly higher than heterozygous mutant group and wild type group.

Recent progress and challenges in screening and characterization of UGT1A1 inhibitors

Uridine-diphosphate glucuronosyltransferase 1A1 (UGT1A1) is an important conjugative enzyme in mammals that is responsible for the conjugation and detoxification of both endogenous and xenobiotic compounds. Strong inhibition of UGT1A1 may trigger adverse drug/herb-drug interactions, or result in metabolic disorders of endobiotic metabolism. Therefore, both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have recommended assaying the inhibitory potential of drugs under development on the human UGT1A1 prior to approval. This review focuses on the significance, progress and challenges in discovery and characterization of UGT1A1 inhibitors. Recent advances in the development of UGT1A1 probes and their application for screening UGT1A1 inhibitors are summarized and discussed in this review for the first time. Furthermore, a long list of UGT1A1 inhibitors, including information on their inhibition potency, inhibition mode, and affinity, has been prepared and analyzed. Challenges and future directions in this field are highlighted in the final section. The information and knowledge that are presented in this review provide guidance for rational use of drugs/herbs in order to avoid the occurrence of adverse effects UGT1A1 inhibition, as well as presenting methods for rapid screening and characterization of UGT1A1 inhibitors and for facilitating investigations on UGT1A1-ligand interactions.

Study on hepatotoxicity of physcion based on liver metabolism in vitro / 中国中药杂志

To evaluate the hepatotoxicity risks of physcion on the basis of the bilirubin metabolism mediated by glucuronidation of UDP-glucuronosyltransferases 1A1(UGT1A1 enzyme). The monomers were added into the rat liver microsomes to test the hepatotoxicity by using bilirubin as UGT1A1 enzyme substrate, with apparent inhibition constant K_i as the evaluation index. Liver microsome incubation in vitro was adopted to initiate phase Ⅱ metabolic reaction and investigate the inhibitory effect of physcion. Then the phase Ⅰ and Ⅱ metabolic reactions were initiated to investigate the comprehensive inhibition of metabolites and prototype components. The results showed that when only the phase Ⅱ reaction was initiated, physcion directly acted on the UGT1A1 enzyme in a prototype form, exhibited weak inhibition and the inhibition type was mixed inhibition; When the phase Ⅰ and Ⅱ reactions were initiated simultaneously, the inhibitory effects of physcion on UGT1A1 enzyme became strong and the inhibition type was mixed inhibition, suggesting that physcion had phase Ⅰ and Ⅱ metabolic processes, and the metabolites had strong inhibitory effect on UGT1A1 enzyme. This experiment preliminarily proved that the metabolites of physcion may be the main components to induce hepatotoxicity.

Relationship between UGT1A1 gene polymorphisms and irinotecan-induced severe adverse events / 中华肿瘤杂志

Objective@#To investigate the relationship between UGT1A1*6, UGT1A1*28, UGT1A1*60 and UGT1A1*93 polymorphisms and irinotecan-induced severe adverse reactions(grade 3-4 delayed diarrhea and neutropenia) in Chinese cancer patients.@*Methods@#A total of 141 cancer patients treated with irinotecan were enrolled in this study. Peripheral venous blood was collected and genomic DNA was extracted. The genetic polymorphisms of UGT1A1*6, UGT1A1*28, UGT1A1*60 and UGT1A1*93 were analyzed by PCR and direct sequencing. The adverse reactions during chemotherapy were observed and recorded. The incidence of severe adverse reactions was compared among patients with different genotypes.@*Results@#Among 141 patients, the cases with UGT1A1*6 GG, GA and AA genotypes were 71, 54 and 16, while those with UGT1A1*28 TA6/6, TA6/7 and TA7/7 genotypes were 105, 33 and 3, respectively. The cases with UGT1A1*60 AA, AC and CC genotypes were 52, 80 and 9, while those with UGT1A1*93 GG, GA and AA genotypes were 105, 32 and 4, respectively. The patients with grade 3-4 delayed diarrhea and neutropenia were 23 and 56, respectively. Multivariate logistic regression analysis showed that UGT1A1*6 and UGT1A1*60 genetic polymorphisms were independent factors influencing the occurrence of grade 3-4 delayed diarrhea. The risk of grade 3-4 delayed diarrhea in homozygous AA carriers of UGT1A1*6 increased 3.79 times compared with that in wild-type GG carriers (95%CI: 1.35-10.67). Moreover, the risk of grade 3-4 delayed diarrhea in homozygous CC carriers of UGT1A1*60 was 20.42 times compared with that in wild-type AA carriers (95%CI: 3.52-118.33). In addition, UGT1A1*28 genetic polymorphism was an independent factor of the occurrence of grade 3-4 neutropenia. The patients with homozygous TA7/7 carriers of UGT1A1*28 had an 1.61 times higher risk of grade 3-4 neutropenia compared with those with wild-type TA6/6 carriers (95%CI: 1.44-12.65). There was no correlation between UGT1A1*93 genetic polymorphism and severe adverse reactions caused by irinotecan.@*Conclusion@#The cancer patients who carried UGT1A1*6, UGT1A1*28 and UGT1A1*60 gene polymorphisms have high risk of severe adverse events caused by irinotecan-based chemotherapy.

Study on spectrum of UGT1A1 mutations in connection with inherited non-hemolytic unconjugated hyperbilirubinemia / 中华肝脏病杂志

Objective@#To compare and analyze patient’s general condition, changes in laboratory parameters, and the spectrum of UGT1A1 mutations in patients with inherited non-hemolytic unconjugated hyperbilirubinemia.@*Methods@#A retrospective study was conducted at Nanjing Second Hospital from January 2015 to July 2018 and patients’ demographic characteristics, liver function test, and UGT1A1 gene were analyzed. The categorical variable data were compared by χ 2 test. The normal distribution continuous variable data were compared by t-test and the non-normal distribution continuous variable data were compared using Mann-Whitney U test.@*Results@#Of the 51 patients with inherited non-hemolytic unconjugated hyperbilirubinemia, 44 (86.3%) were Gilbert’s syndrome (GS) and seven (13.7%) were Crigler-Najjar syndrome type II (CNS- II). The male to female ratio was 2.9:1 and the average age was 36.11 ± 13.17 years. Six variant types were detected: C. -40_-39insTA, C. -3279T > G, c.211G > A (p.G71R), c.686C > A (p.P229Q), c.1091C > T (p.P364L), c.1456T > G (P.Y486D). Among them, c.211G > A accounted for 58.82% (30/51), c.-40_-39insTA accounted for 27.5% (14/51), and c.1456T > G accounted for 25.5% (13/51). The total bilirubin(TB) and unconjugated bilirubin (UCB) in CNS-II patients were significantly higher than GS patients[155.91 (130 ~ 207) vs. 38.25(29 ~ 52.15) μmol/L, U = 0, P < 0.01; 144.13 (120.8 ~ 197) vs. 30.00 (21.7 ~ 46.75) μmol/L, U = 0.00, P < 0.01, respectively]. Exon mutations of c.1091C > T and c.1456T > G were statistically significant(P < 0.01).There were no differences in age, TB, UCB, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) between the c.211G > A homozygous variants and heterozygous variants (P > 0.05).@*Conclusion@#The common pathogenic mutations of UGT1A1 gene were c.211G > A, c.-40_-39insTA, c.1456T > G. c.211G > A. The mutation has little effect on the level of total bilirubin, but c.1091C > T, c.1456T > G mutations has great influence on the level of total bilirubin.

Study on UGT1 A1?6 gene polymorphisms in cancer patients of Han population in Anhui area / 中国药理学通报

Aim To investigate the gene frequency of UGT1 A1?6 in cancer patients in Anhui Han popula-tion. Methods The 222 cases of blood samples of Han cancer patients were collected from different re-gions of Anhui province, and the UGT1A1?6 geno-types were detected by in situ hybridization fluorescencestaining. Results Patients with a UGT1A1?6 wild type ( GG ) accounted for ( 159 cases, 71. 62％) , which were higher than those of heterozygous mutations ( GA, 52 cases, 23. 42％) and of homozygous muta-tions ( AA, 11 cases, 4. 96％) of the total cases. The mutation rate of UGT1 A1?6 was 16. 67％, and partic-ularly in patients with esophageal cancer it was 43. 75％. The rates of mutation in the patients in Ma ' anshan and Chuzhou were 40. 01％ and 34. 62％, re-spectively, both significantly higher than those of othertumors and regions. Conclusions Cancer patients in Anhui Han population have a high mutant frequency of UGT1 A1?6 . The UGT1 A1?6 genotyping can indi-rectly predict the risk of irinotecan's adverse reaction, which obviously enhances the potentially individualized treatment of irinotecan.

Pharmacogenetic testing in oncology: a Brazilian perspective

Pharmacogenetics, a major component of individualized or precision medicine, relies on human genetic diversity. The remarkable developments in sequencing technologies have revealed that the number of genetic variants modulating drug action is much higher than previously thought and that a true personalized prediction of drug response requires attention to rare mutations (minor allele frequency, MAF<1%) in addition to polymorphisms (MAF>1%) in pharmacogenes. This has major implications for the conceptual development and clinical implementation of pharmacogenetics. Drugs used in cancer treatment have been major targets of pharmacogenetics studies, encompassing both germline polymorphisms and somatic variants in the tumor genome. The present overview, however, has a narrower scope and is focused on germline cancer pharmacogenetics, more specifically, on drug/gene pairs for which pharmacogenetics-informed prescription guidelines have been published by the Clinical Pharmacogenetics Implementation Consortium and/or the Dutch Pharmacogenetic Working Group, namely, thiopurines/TPMT, fluoropyrimidines/UGT1A1, irinotecan/UGT1A1 and tamoxifen/CYP2D6. I begin by reviewing the general principles of pharmacogenetics-informed prescription, pharmacogenetics testing and the perceived barriers to the adoption of routine pharmacogenetics testing in clinical practice. Then, I highlight aspects of the pharmacogenetics testing of the selected drug-gene pairs and finally present pharmacogenetics data from Brazilian studies pertinent to these drug-gene pairs. I conclude with the notion that pharmacogenetics testing has the potential to greatly benefit patients by enabling precision medicine applied to drug therapy, ensuring better efficacy and reducing the risk of adverse effects.