Individual Irinotecan Therapy Under the Guidance of Pre-Treated UGT1A1*6 Genotyping in Gastric Cancer

Background: Severe delayed diarrhea and hematological toxicity limit the use of irinotecan. Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) is a critical enzyme in irinotecan metabolism. The study aims to investigate the safety and efficacy of irinotecan under the guidance of the pre-treatment UGT1A1 genotype in the second-line treatment of gastric cancer. Methods: This study involved 110 patients. Irinotecan was injected intravenously every 3 weeks, and the dose of irinotecan was determined by polymorphism of the UGT1A1 gene, which was divided into three groups (125 mg/m2: GG type; 100 mg/m2: GA type; 75 mg/m2: AA type). The primary end point was overall survival (OS), the secondary end points were progression-free survival (PFS) and safety. Results: One hundred and seven patients received irinotecan treatment and three patients with AA type received paclitaxel treatment. Among 107 patients, there were no significant differences in PFS (4.8 m vs 4.9 m vs 4.4 m; p = 0.5249) and OS (9.3 m vs 9.3 m vs NA; p = 0.6821) among patients with GG/GA/AA subtypes after dose adjustment. For the patient with homozygosity mutation, treatment was switched to paclitaxel. There were no significant differences in PFS and OS among patients with different alleles or after dose adjustment (p > 0.05). There was a significant difference in the risk of delayed diarrhea (p = 0.000), leukopenia (p = 0.003) and neutropenia (p = 0.000) in patients with different UGT1A1*6 genotypes, while no difference in patients with different UGT1A1*28 genotypes. Additionally, grade 3/4 diarrhea, neutropenia, and leukopenia were significantly more common in AA genotype patients compared to GG (2%, 19%, 24%) or GA (23%, 31%, 31%) genotype patients. Conclusion: Individual irinotecan treatment shows encouraging survival and tolerability outcomes in patients with GG/GA subtype. Irinotecan may be not suitable for patients with AA subtype.

Quantitative analysis of the UDP-glucuronosyltransferase transcriptome in human tissues

UDP-glucuronosyltransferases (UGTs) are phase II drug metabolizing enzymes that play important roles in the detoxification of endogenous and exogenous substrates. The 22 human UGTs belong to four families (UGT1, UGT2, UGT3, and UGT8) and differ in their expression, substrate specificity, UDP-sugar preference, and physiological functions. Differential expression/activity of the UGTs contributes to interperson variability in drug responses and toxicity, hormone homeostasis, and disease/cancer risks. However, in normal tissues, the tissue-specific expression profiles and transcriptional regulation of the UGTs are still not fully understood. In this study, we comprehensively analyzed the transcriptome of 22 UGTs in 54 human tissues/regions using RNAseq data from GTEx. We then validated the findings in the liver and small intestine samples using real-time PCR. Our results showed large interindividual variability across tissues in the expression of each UGT and the overall composition of UGT pools, consisting of different UGTs and their splice isoforms. Our results also revealed coexpression of the UGTs, Cytochrome P450s, and many transcription factors in the liver, suggesting potential coregulation or functional coordination. Our results provide the groundwork for future studies to detail further the regulation of the expression and activity of the UGTs.

Properties of Dietary Flavone Glycosides, Aglycones, and Metabolites on the Catalysis of Human Endoplasmic Reticulum Uridine Diphosphate Glucuronosyltransferase 2B7 (UGT2B7)

Flavone glycosides, their aglycones, and metabolites are the major phytochemicals in dietary intake. However, there are still many unknowns about the cellular utilization and active sites of these natural products. Uridine diphosphate glucuronosyltransferases (UGTs) in the endoplasmic reticulum have gene polymorphism distribution in the population and widely mediate the absorption and metabolism of endogenous and exogenous compounds by catalyzing the covalent addition of glucuronic acid and various lipophilic chemicals. Firstly, we found that rutin, a typical flavone O-glycoside, has a stronger UGT2B7 binding effect than its metabolites. After testing a larger number of flavonoids with different aglycones, their aglycones, and metabolites, we demonstrated that typical dietary flavone O-glycosides generally have high binding affinities towards UGT2B7 protein, but the flavone C-glycosides and the phenolic acid metabolites of flavones had no significant effect on this. With the disposition of 4-methylumbelliferone examined by HPLC assay, we determined that 10 μM rutin and nicotifiorin could significantly inhibit the activity of recombinant UGT2B7 protein, which is stronger than isovitexin, vitexin, 3-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid. In addition, in vitro experiments showed that in normal and doxorubicin-induced lipid composition, both flavone O-glycosides rutin and flavone C-glycosides isovitexin at 10 μM had no significant effect on the expression of UGT1A1, UGT2B4, UGT2B7, and UGT2B15 genes for 24 h exposure. The obtained results enrich the regulatory properties of dietary flavone glycosides, aglycones, and metabolites towards the catalysis of UGTs and will contribute to the establishment of a precise nutritional intervention system based on lipid bilayers and theories of nutrients on endoplasmic reticulum and mitochondria communication.

Synthetic augmentation of bilirubin metabolism in human pluripotent stem cell-derived liver organoids

UGT1A1 (UDP glucuronosyltransferase family 1 member A1) is the primary enzyme required for bilirubin conjugation, which is essential for preventing hyperbilirubinemia. Animal models lack key human organic anion transporting polypeptides with distinct epigenetic control over bilirubin metabolism, necessitating a human model to interrogate the regulatory mechanism behind UGT1A1 function. Here, we use induced pluripotent stem cells to develop human liver organoids that can emulate conjugation failure phenotype. Bilirubin conjugation assays, chromatin immunoprecipitation, and transcriptome analysis elucidated the role of glucocorticoid antagonism in UGT1A1 activation. This antagonism prevents the binding of transcriptional repressor MECP2 at the expense of NRF2 with associated off-target effects. Therefore, we introduced functional GULO (L-gulonolactone oxidase) in human organoids to augment intracellular ascorbate for NRF2 reactivation. This engineered organoid conjugated more bilirubin and protected against hyperbilirubinemia when transplanted in immunosuppressed Crigler-Najjar syndrome rat model. Collectively, we demonstrate that our organoid system serves as a manipulatable model for interrogating hyperbilirubinemia and potential therapeutic development.

UGT1A1 morpholino antisense oligonucleotides produce mild unconjugated hyperbilirubinemia in cyclosporine A-induced cardiovascular disorders in BLC57 mice

This study aimed to investigate the induction of mild unconjugated hyperbilirubinemia in hepatic UGT1A1 inhibition by Morpholinos antisense in CsA-treated BLC57 mice in comparison with the efficacy of chitosan (CH) as an anti-hypolipidemic natural product. Antisense morpholino oligonucleotides were injected intravenously into CsA-treated mice for 14 days thrice a week. Serum biochemical parameters, antioxidant status, and gene expression analysis of eNOS, PPAR-α, NF-kB, cFn, AT1-R, and ETA-R were determined in cardiac tissues with confirmation by histopathology. Inhibition of UGT1A1 significantly elevated serum unconjugated bilirubin within a physiological range. Furthermore, induced mild hyperbilirubinemia reduces hyperlipidemia, improves antioxidant status, and significantly increases the expression of the cardiac PPAR-α gene while decreasing, ETA-R, iNOS, NF-kB, cFn and AT1-R gene expression in CsA-treated mice. Importantly, mild unconjugated hyperbilirubinemia within physiological ranges may be used as a novel therapeutic strategy to lower hyperlipidemia, atherosclerosis, hypertension, and the CVD outcomes in CsA- treated transplant recipients.

Irinotecan-Induced Toxicity: A Pharmacogenetic Study Beyond UGT1A1

BACKGROUND AND OBJECTIVE

Side effects of irinotecan treatment can be dose limiting and may impair quality of life. In this study, we investigated the correlation between single nucleotide polymorphisms (SNPs) in genes encoding enzymes involved in the irinotecan metabolism and transport, outside UGT1A1, and irinotecan-related toxicity. We focused on carboxylesterases, which are involved in formation of the active metabolite SN-38 and on drug transporters.

METHODS

Patients who provided written informed consent at the Erasmus Medical Center Cancer Institute to the Code Geno study (local protocol: MEC02-1002) or the IRI28-study (NTR-6612) were enrolled in the study and were genotyped for 15 SNPs in the genes CES1, CES2, SLCO1B1, ABCB1, ABCC2, and ABCG2.

RESULTS

From 299 evaluable patients, 86 patients (28.8%) developed severe irinotecan-related toxicity. A significantly higher risk of toxicity was seen in ABCG2 c.421C>A variant allele carriers (P = 0.030, OR 1.88, 95% CI 1.06-3.34). Higher age was associated with all grade diarrhea (P = 0.041, OR 1.03, 95% CI 1.00-1.06). In addition, CES1 c.1165-41C>T and CES1 n.95346T>C variant allele carriers had a lower risk of all-grade thrombocytopenia (P = 0.024, OR 0.42, 95% CI 0.20-0.90 and P = 0.018, OR 0.23, 95% CI 0.08-0.79, respectively).

CONCLUSION

Our study indicates that ABCG2 and CES1 SNPs might be used as predictive markers for irinotecan-induced toxicity.

Il-6 and UGT1A1 variations may related to furosemide resistance in heart failure patients

Furosemide is a diuretic and is used for the treatment of patients with heart failure (HF). It has been found that in some HF patients, the drug does not treat patients efficiently. This condition is named as furosemide resistance. In this study, it is aimed to investigate the relationship between UDP-glucuronosyltransferase 1 (UGT1A1) and interleukine-6 (IL-6) variations with furosemide resistance in HF patients. Sixty HF patients using furosemide (patient group) and 30 healthy individuals (control group) were enrolled in this study. Patients were divided into two subgroups as non-responders (furosemide resistant) group (n = 30) and the responders (non-resistant) group (n = 30) according to the presence of furosemide resistance (n = 30). Variations in the first exon of UGT1A1 and rs1800795 and rs1800796 variations in IL-6 were analyzed by direct sequencing and real-time polymerase chain reaction (RT-PCR), respectively. The effects of newly detected mutations on 3-D protein structure were analyzed by in silico analysis. At the end of the study, 11 variations were detected in UGT1A1, of which nine of them are novel and eight of them cause amino acid change. Also, rs1800795 and rs1800796 variations were detected in all the groups. When patient and control groups were compared with each other, rs1800796 mutation in IL-6 was found statistically high in the patient group (p = 0.027). When the three groups were compared with each other, similarly, rs1800796 mutation in IL-6 was found statistically high in the non-responders group (p = 0.043). When allele distributions were compared between the patient and control groups, the C allele of rs1800795 mutation in IL-6 was found statistically high in the patient group (p = 0.032). When allele distributions were compared between the three groups, 55T-insertion in UGT1A1 was found statistically high in the non-responders group (p = 0.017). According to in silico analysis results, two variations were found deleterious and six variations were detected as probably damaging to protein functions. Our study may contribute to the elucidation of pharmacogenetic features (drug response-gene relationship) and the development of individual-specific treatment strategies in HF patients using furosemide.

Gene Therapy in Patients with the Crigler-Najjar Syndrome

BACKGROUND

Patients with the Crigler-Najjar syndrome lack the enzyme uridine diphosphoglucuronate glucuronosyltransferase 1A1 (UGT1A1), the absence of which leads to severe unconjugated hyperbilirubinemia that can cause irreversible neurologic injury and death. Prolonged, daily phototherapy partially controls the jaundice, but the only definitive cure is liver transplantation.

METHODS

We report the results of the dose-escalation portion of a phase 1-2 study evaluating the safety and efficacy of a single intravenous infusion of an adeno-associated virus serotype 8 vector encoding UGT1A1 in patients with the Crigler-Najjar syndrome that was being treated with phototherapy. Five patients received a single infusion of the gene construct (GNT0003): two received 2×1012 vector genomes (vg) per kilogram of body weight, and three received 5×1012 vg per kilogram. The primary end points were measures of safety and efficacy; efficacy was defined as a serum bilirubin level of 300 μmol per liter or lower measured at 17 weeks, 1 week after discontinuation of phototherapy.

RESULTS

No serious adverse events were reported. The most common adverse events were headache and alterations in liver-enzyme levels. Alanine aminotransferase increased to levels above the upper limit of the normal range in four patients, a finding potentially related to an immune response against the infused vector; these patients were treated with a course of glucocorticoids. By week 16, serum bilirubin levels in patients who received the lower dose of GNT0003 exceeded 300 μmol per liter. The patients who received the higher dose had bilirubin levels below 300 μmol per liter in the absence of phototherapy at the end of follow-up (mean [±SD] baseline bilirubin level, 351±56 μmol per liter; mean level at the final follow-up visit [week 78 in two patients and week 80 in the other], 149±33 μmol per liter).

CONCLUSIONS

No serious adverse events were reported in patients treated with the gene-therapy vector GNT0003 in this small study. Patients who received the higher dose had a decrease in bilirubin levels and were not receiving phototherapy at least 78 weeks after vector administration. (Funded by Genethon and others; ClinicalTrials.gov number, NCT03466463.).

Chlorpyrifos and chlorfenapyr resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) relies on UDP-glucuronosyltransferases

Fall armyworm, Spodoptera frugiperda (J. E. Smith), has become an important agricultural pest worldwide. S. frugiperda is mainly controlled by the chemical insecticides, whereas the frequent application of insecticides would result in the resistance development. Insect uridine diphosphate-glucuronosyltransferases (UGTs), as phase II metabolism enzymes, play vital roles in the breakdown of endobiotic and xenobiotics. In this study, 42 UGT genes were identified by RNA-seq, including 29 UGT genes were elevated compared to the susceptible population, and the transcript levels of 3 UGTs (UGT40F20, UGT40R18, and UGT40D17) were increased by more than 2.0-fold in the field populations. Expression pattern analysis revealed that S. frugiperda UGT40F20, UGT40R18, and UGT40D17 were increased by 6.34-, 4.26-, and 8.28-fold, compared the susceptible populations, respectively. The expression of UGT40D17, UGT40F20, and UGT40R18 was affected after exposure to phenobarbital, chlorpyrifos, chlorfenapyr, sulfinpyrazone, and 5-nitrouracil. The induced expression of UGT genes may have improved UGT enzymatic activity, while the inhibition of UGTs genes expression may decreased UGT enzymatic activity. Sulfinpyrazone, and 5-nitrouracil, significantly increased the toxicity of chlorpyrifos and chlorfenapyr, as well as phenobarbital significantly reduced the toxicity of chlorpyrifos and chlorfenapyr against the susceptible populations and field populations of S. frugiperda. The suppression of UGTs (UGT40D17, UGT40F20, and UGT40R18) significantly increased the insensitivity of the field populations to chlorpyrifos and chlorfenapyr. These findings strongly supported our viewpoint that UGTs may play a critical role in insecticide detoxification. This study provides a scientific basis for the management of S. frugiperda.

Bearing variant alleles at uridine glucuronosyltransferase polymorphisms UGT2B7 -161C > T (rs7668258) or UGT1A4*3 c.142 T > G (rs2011425) has no relevant consequences for lamotrigine troughs in adults with epilepsy

PURPOSE

To estimate whether epilepsy patients with variant UGT2B7 -161C > T (rs7668258) or UGT1A4*3 c.142 T > G (rs2011425) alleles differ from their wild-type (wt) peers in exposure to lamotrigine.

METHODS

Consecutive adults on lamotrigine monotherapy or lamotrigine + valproate co-treatment undergoing routine therapeutic drug monitoring, otherwise generally healthy and free of interacting drugs, were genotyped for UGT2B7 -161C > T and UGT1A4*3 c.142 T > G. Heterozygous, variant homozygous, or combined heterozygous/variant homozygous subjects were compared to their wt controls for dose-adjusted lamotrigine troughs with adjustment for age, sex, body weight, rs7668258/rs2011425, polymorphisms of efflux transporter proteins ABCG2 c.421C > A (rs2231142) and ABCB1 1236C > T (rs1128503), and level of exposure to valproate using covariate entropy balancing.

RESULTS

Of the 471 included patients, 328 (69.6%) were on monotherapy and 143 were co-treated with valproate. Dose-adjusted lamotrigine troughs in UGT2B7 -161C > T heterozygous (CT, n = 237) or variant homozygous (TT, n = 115) subjects were closely similar to those in their wt controls (CC, n = 119): geometric means ratios (GMRs) (frequentist and Bayes) 1.00 (95%CI 0.86-1.16) and 1.00 (95%CrI 0.83-1.22) for CT vs. CC; and 0.97 (0.81-1.17) and 0.97 (0.80-1.20) for TT vs. CC subjects. Lamotrigine troughs were also closely similar in UGT1A4*3 c.142 T > G variant carriers (n = 106: 102 TG + 4 GG subjects) and wt controls (TT, n = 365): GMR = 0.95 (0.81-1.12) frequentist, 0.96 (0.80-1.16) Bayes. GMRs for variant carriers vs. wt controls were around unity also at different levels of exposure to valproate.

CONCLUSION

Dose-adjusted lamotrigine troughs in epilepsy patients with variant UGT2B7 -161C > T or UGT1A4*3 c.142 T > G alleles are equivalent to those in their respective wt peers.

Association of Low Serum Bilirubin Concentrations and Promoter Variations in the UGT1A1 and HMOX1 Genes with Type 2 Diabetes Mellitus in the Czech Population

Bilirubin has potent biological beneficial effects, protecting against atherosclerosis, obesity, and metabolic syndrome. The aim of this study was to assess serum bilirubin concentrations and (TA)n and (GT)n microsatellite variations in the promoter regions of the UGT1A1 and HMOX1 genes, respectively, in patients with type 2 diabetes mellitus (T2DM). The study was carried out in 220 patients with T2DM and 231 healthy control subjects, in whom standard biochemical tests were performed. The (TA)n and (GT)n dinucleotide variations were determined by means of fragment (size-based) analysis using an automated capillary DNA sequencer. Compared to controls, both male and female patients with T2DM had lower serum bilirubin concentrations (9.9 vs. 12.9 μmol/L, and 9.0 vs. 10.6 μmol/L, in men and women, respectively, p < 0.001). Phenotypic Gilbert syndrome was much less prevalent in T2DM patients, as was the frequency of the (TA)7/7UGT1A1 genotype in male T2DM patients. (GT)nHMOX1 genetic variations did not differ between diabetic patients and controls. Our results demonstrate that the manifestation of T2DM is associated with lower serum bilirubin concentrations. Consumption of bilirubin due to increased oxidative stress associated with T2DM seems to be the main explanation, although (TA)n repeat variations in UGT1A1 partially contribute to this phenomenon.

UGT1A1 genotype-guided dosing of irinotecan: time to prioritize patient safety

Tweetable abstract Pretreatment UGT1A1 genotyping and a 70% irinotecan dose intensity in poor metabolizers is safe, feasible, cost-effective and essential for safe irinotecan treatment in cancer patients. It is time to update guidelines to swiftly enable the implementation of UGT1A1 genotype-guided irinotecan dosing in routine oncology care.

Genetic polymorphisms of microsomal epoxide hydrolase and UDP-glucuronosyltransferase (UGT) and its effects on plasma carbamazepine levels and metabolic ratio in persons with epilepsy of South India: A cross-sectional genetic association study

OBJECTIVES

Carbamazepine (CBZ), an anti-seizure drug, is widely prescribed for the management of focal seizures. At a given therapeutic dose, CBZ exhibits marked interindividual variation in the plasma CBZ levels. The aim wasto study the influence of EPHX1 c.337 T>C and UGT2B7*2 genetic polymorphisms on plasma carbamazepine (CBZ) levels in persons with epilepsy (PWE) from South India.

METHODS

115 PWE belong to South India origin who are on carbamazepine monotherapy were recruited. Genotyping of the two variants weredone using RT-PCR method. PWE who had seizure freedom for one year and their last dose which was not changed for one year duration were included and their plasma levels of CBZ and its active metabolite CBZ 10,11 epoxide were analysed by reverse phase HPLC.

RESULTS

In EPHX1 c. 337 (T>C) polymorphism, the PWE carrying CC had lower plasma CBZ levels when compared to CT genotype (2.45 μg/ml vs 3.15 μg/ml. In UGT2B7*2, PWE carrying homozygous mutant TT had higher levels when compared with CT (3.09 μg/ml vs 2.74 μg/ml) genotype but found no statistical significance. Mutant genotype of EPHX1 (CC) had higher metabolic ratio compared to TT genotype (1.33 vs 1.17) but not found to be statistically significant. Mutant genotype of UGT2B7*2 (TT) was found to be having lower metabolic ratio when compared with CC genotype (1.18 vs 1.35; p value =0.08).

CONCLUSION

PWE carrying EPHX1 c.337 T>C (rs1051740) and UGT2B7*2 (rs7439366) genetic polymorphisms did not affect the plasma CBZ levels and metabolic ratio of PWE of South Indian origin. However, this finding should be confirmed in a larger sample size which may help in optimization and personalized CBZ therapy in South Indians.

The structural basis of conserved residue variant effect on enzyme activity of UGT2B15

UDP-glucuronosyltransferase 2B15 (UGT2B15) is a crucial phase II drug-metabolizing enzyme, which glucuronidates various compounds, including clinical drugs and hormones. Mutants might affect glucuronidation, leading to a disruption of drug metabolism in vivo and decrease of therapeutic effect. Here, we mainly analyzed two representative mutants, H401P and L446S, on UGT2B15 activity using glucuronidation assays, molecular dynamic (MD) simulation and X-ray diffraction methods. The enzyme activity of L446S obviously increased six-fold than the wild type, although the enzyme activities of P191L, T374A, and H401P were lost apparently. Furthermore, we used MD simulations to calculate the energy change in the catalytic process of H401P and L446S, and the results indicated the free binding energies of H401P mutant to oxazepam and UDPGA were -30.98 ± 1.00 kcal/mol and -36.42 ± 1.04 kcal/mol, respectively, increased obviously compared to wild type, suggesting the mutation on position 401 had a crucial effect on the catalysis. Moreover, the three-dimensional structure of UGT2B15 C-terminal domain L446S was determined through protein crystallography and X-ray diffraction technology and the results suggested that one more hydrogen bonding between S446 and K410 was formed in the S446 crystal structure, compared to the wild type. Isothermal titration calorimetry assay further revealed the K_d values of C-terminal domain of UGT2B15 harbored L446S towards the cofactor UDPGA was similar to the value of wild type. Above all, our results pointed out that H401P and L446S affected the enzyme activity by different mechanism. Our work provided a helpful mechanism for variance explained in the UGTs catalyzation process.

Relevance of Human Aldoketoreductases and Microbial β-Glucuronidases in Testosterone Disposition

Testosterone exhibits high variability in pharmacokinetics and glucuronidation after oral administration. Although testosterone metabolism has been studied for decades, the impact of UGT2B17 gene deletion and the role of gut bacterial β-glucuronidases on its disposition are not well characterized. We first performed an exploratory study to investigate the effect of UGT2B17 gene deletion on the global liver proteome, which revealed significant increases in proteins from multiple biological pathways. The most upregulated liver proteins were aldoketoreductases [AKR1D1, AKR1C4, AKR7A3, AKR1A1, and 7-dehydrocholesterol reductase (DHCR7)] and alcohol or aldehyde dehydrogenases (ADH6, ADH1C, ALDH1A1, ALDH9A1, and ALDH5A). In vitro assays revealed that AKR1D1 and AKR1C4 inactivate testosterone to 5β-dihydrotestosterone (5β-DHT) and 3α,5β-tetrahydrotestosterone (3α,5β-THT), respectively. These metabolites also appeared in human hepatocytes treated with testosterone and in human serum collected after oral testosterone dosing in men. Our data also suggest that 5β-DHT and 3α, 5β-THT are then eliminated through glucuronidation by UGT2B7 in UGT2B17 deletion individuals. Second, we evaluated the potential reactivation of testosterone glucuronide (TG) after its secretion into the intestinal lumen. Incubation of TG with purified gut microbial β-glucuronidase enzymes and with human fecal extracts confirmed testosterone reactivation into testosterone by gut bacterial enzymes. Both testosterone metabolic switching and variable testosterone activation by gut microbial enzymes are important mechanisms for explaining the disposition of orally administered testosterone and appear essential to unraveling the molecular mechanisms underlying UGT2B17-associated pathophysiological conditions. SIGNIFICANCE STATEMENT: This study investigated the association of UGT2B17 gene deletion and gut bacterial β-glucuronidases with testosterone disposition in vitro. The experiments revealed upregulation of AKR1D1 and AKR1C4 in UGT2B17 deletion individuals, and the role of these enzymes to inactivate testosterone to 5β-dihydrotestosterone and 3α, 5β-tetrahydrotestosterone, respectively. Key gut bacterial species responsible for testosterone glucuronide activation were identified. These data are important for explaining the disposition of exogenously administered testosterone and appear essential to unraveling the molecular mechanisms underlying UGT2B17-associated pathophysiological conditions.

Oral arsenic administration to humanizedUDP-glucuronosyltransferase1 neonatal mice induces UGT1A1 through a dependence on Nrf2 and PXR

Inorganic arsenic (iAs) is an environmental toxicant that can lead to severe health consequences, which can be exacerbated if exposure occurs early in development. Here, we evaluated the impact of oral iAs treatment on UDP-glucuronosyltransferase 1A1 (UGT1A1) expression and bilirubin metabolism in humanized UGT1 (hUGT1) mice. We found that oral administration of iAs to neonatal hUGT1 mice that display severe neonatal hyperbilirubinemia leads to induction of intestinal UGT1A1 and a reduction in total serum bilirubin values. Oral iAs administration accelerates neonatal intestinal maturation, an event that is directly associated with UGT1A1 induction. As a reactive oxygen species producer, oral iAs treatment activated the Keap-Nrf2 pathway in the intestinal tract and liver. When Nrf2-deficient hUGT1 mice (hUGT1/Nrf2-/-) were treated with iAs, it was shown that activated Nrf2 contributed significantly toward intestinal maturation and UGT1A1 induction. However, hepatic UGT1A1 was not induced upon iAs exposure. We previously demonstrated that the nuclear receptor PXR represses liver UGT1A1 in neonatal hUGT1 mice. When PXR was deleted in hUGT1 mice (hUGT1/Pxr-/-), derepression of UGT1A1 was evident in both liver and intestinal tissue in neonates. Furthermore, when neonatal hUGT1/Pxr-/- mice were treated with iAs, UGT1A1 was superinduced in both tissues, confirming PXR release derepressed key regulatory elements on the gene that could be activated by iAs exposure. With iAs capable of generating reactive oxygen species in both liver and intestinal tissue, we conclude that PXR deficiency in neonatal hUGT1/Pxr-/- mice allows greater access of activated transcriptional modifiers such as Nrf2 leading to superinduction of UGT1A1.

A Novel SPTA1 Mutation in a Patient with Hereditary Spherocytosis without a Family History and Coexisting Gilbert's Syndrome

Most patients with hereditary spherocytosis (HS) have a family history of disease, while those without such a history are difficult to diagnose. We herein report a case of HS with no family history harboring a novel heterozygous mutation of SPTA1, c.2161G>A (p.E721K), and a homozygous polymorphism of UGT1A1*6. In silico analyses suggested that the mutation might contribute to the pathogenesis of HS. The coexistence of HS and Gilbert's syndrome increases the risk of gallstones. Therefore, splenectomy, alone or in combination with cholecystectomy, is recommended. The determination of genetic diathesis provides useful information for the management of hemolytic anemia.

UGT1A1 variants in Chinese Uighur and Han newborns and its correlation with neonatal hyperbilirubinemia

To explore the correlation between UGT1A1 variant and neonatal hyperbilirubinemia in Chinese Uighur and Han populations. We conducted this study in Urumqi, China. Umbilical cord blood specimens and clinical information of term infants born in the studied center were collected. Variation status of UGT1A1 was determined by direct sequencing or capillary electrophoresis analysis. 102 Uighur and 99 Han normal term neonates, together with 19 hospitalized term newborns (10 Uighur and 9 Han) due to significant hyperbilirubinemia were enrolled into the final analysis. The incidence of neonates with high-risk transcutaneous bilirubin level (TCB) were much higher in Han newborns than in Uighur newborns(P = 0.01). Also, there was statistically significant difference in (TA) 7 promoter mutation of UGT1A1 between Han and Uighur group(χ2 = 4.675, P = 0.03). Furthermore, exon mutation (c.211 and /or c.1091) in UGT1A1 gene was significantly associated with increased TCB level (ORadj = 1.41, 95%CI: 0.25-2.51, P = 0.002) and higher risk of hyperbilirubinemia in both Han and Uighur infants after adjusted for covariates (ORadj = 2.21, 95%CI: 1.09-4.49, P = 0.03). In conclusion, UGT1A1 promoter polymorphism seem to be an important genetic modulator of plasma bilirubin level and neonatal hyperbilirubinemia risk within ethnic groups. Genetic assessment of UGT1A1 coding variants may be useful for clinical diagnosis of neonatal jaundice.

UGT2B7 c.-161C>T polymorphism frequency in Croatian population

Uridine diphosphate glucuronosyltransferase-2B7 (UGT2B7), enzyme responsible for the elimination of a number of xenobiotics through glucuronidation, is expressed in the gut, kidneys, intestines, and brain. However, data on the frequency of UGT2B7 polymorphisms in the Croatian population are limited. The aim of this study was to assess the frequency of the UGT2B7 c.-161C>T (rs7668258) polymorphism in the Croatian population and to compare it with reported frequencies in other populations. This polymorphism is in complete linkage disequilibrium with the UGT2B7 c.802C>T (UGT2B7*2, rs7439366) variant, which is important in clinical medicine. The study reports data of 501 participants from University Hospital Centre Zagreb. All data were collected and analysed retrospectively. Genotyping was performed by real-time polymerase chain reaction (PCR) using the TaqMan® Drug Metabolism Genotyping Assay for UGT2B7 c.-161C>T (rs7668258). We found that 120 (23.95 %) participants were carriers of the UGT2B7 c.-161CC genotype and 255 (50.9 %) were heterozygous carriers (UGT2B7 c.-161CT), while 126 (25.15 %) were homozygous carriers of the variant allele (UGT2B7 c.-161TT). The frequency of the variant UGT2B7 c.-161C>T allele in this study was T=0.506. The frequency of the UGT2B7 c.-161C>T allelic variants and genotypes in the Croatian population is similar to other European populations.

The Mutation Hotspots at UGT1A Locus May Be Associated with Gilbert's Syndrome Affecting the Taiwanese Population

Gilbert's syndrome is mainly diagnosed through genetic analysis and is primarily detected through a mutation in the promoter region of the UGT1A1 gene. However, most of the research has been conducted on Caucasian populations. In this study, we studied the Han population in Taiwan to investigate the possibility of other mutations that could cause Gilbert's syndrome. This study comprised a test group of 45 Taiwanese individuals with Gilbert's syndrome and 180 healthy Taiwanese individuals as a control group. We extracted DNA from the blood samples and then used Axiom Genome-Wide TWB 2.0 array plates for genotyping. Out of 302,771 single nucleotide polymorphisms (SNPs) from 225 subjects, we detected 57 SNPs with the most significant shift in allele frequency; 27 SNPs among them were located in the UGT1A region. Most of the detected SNPs highly correlated with each other and are located near the first exon of UGT1A1, UGT1A3, UGT1A6, and UGT1A7. We used these SNPs as an input for the machine learning algorithms and developed prediction models. Our study reveals a good association between the 27 SNPs detected and Gilbert's syndrome. Hence, this study provides a reference for diagnosing Gilbert's syndrome in the Taiwanese population in the future.

Influence of UGT1A1 Genetic Variants on Free Bilirubin Levels in Japanese Newborns: A Preliminary Study

BACKGROUND

Free bilirubin (Bf) is a better marker than total serum bilirubin (TSB) for predicting bilirubin encephalopathy (BE). To date, two UGT1A1 genetic variants (rs4148323 and rs3064744) have been associated with neonatal hyperbilirubinemia; however, the direct association between UGT1A1 variants and Bf levels in newborns has not been elucidated.

METHODS

We retrospectively analyzed the clinical data of 484 infants, including the genotype data of two UGT1A1 genetic variants. We divided the infants into a high Bf group (Bf ≥ 1.0 µg/dL, n = 77) and a non-high Bf group (Bf < 1.0 µg/dL, n = 407), based on the peak Bf values. Logistic regression analysis was performed to calculate the odds ratios (ORs) for each variant allele compared to wild-type alleles.

RESULTS

The frequencies of the A allele in rs4148323 and (TA)₇ allele in rs3064744 in the high Bf group (29% and 4%, respectively) were significantly different from those in the non-high Bf group (16% and 12%, respectively). In logistic regression analysis, for rs4148323, the A allele was significantly associated with an increased risk of hyper-free bilirubinemia over the G allele (adjusted OR: 1.80, 95% confidence interval [CI]: 1.19-2.72, p < 0.01). However, for rs3064744, the (TA)₇ allele was significantly associated with a decreased risk of hyper-free bilirubinemia over the (TA)₆ allele (adjusted OR: 0.42, 95% CI: 0.18-0.95, p = 0.04).

CONCLUSIONS

This study is the first to show that the A allele in rs4148323 is a risk factor and that the (TA)₇ allele in rs3064744 is a protective factor for developing hyper-free bilirubinemia in Japanese newborns.

Hepatotoxicity with High-Dose Green Tea Extract: Effect of Catechol-O-Methyltransferase and Uridine 5'-Diphospho-glucuronosyltransferase 1A4 Genotypes

The predominant catechin in green tea, epigallocatechin gallate (EGCG), may be hepatotoxic in high doses. Our objective was to investigate the influence of catechol-O-methyltransferase (COMT) and uridine 5'-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotypes on changes in liver injury biomarkers in response to long-term, high-dose green tea extract (GTE) supplementation among postmenopausal women. A secondary analysis was conducted using data from the Minnesota Green Tea Trial (N = 1,075), in which participants were randomized to consume high-dose GTE (843 mg/day EGCG) or placebo capsules for 12 months. Analysis of covariance adjusting for potential confounders was performed to examine changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), AST: ALT ratio, and alkaline phosphatase from baseline to months 3, 6, 9, and 12 across COMT and UGT1A4 genotypes. Mean age and BMI within the GTE group (n = 400) were 59.8 yrs and 25.1 kg/m2, respectively, and 98% of subjects were white. From baseline to month 3, mean AST: ALT ratio change was +1.0% in the COMT (rs4680) A/G genotype versus -4.8% in the A/A genotype (p = 0.03). From baseline to months 6 and 9, respectively, mean ALT change was +78.1% and +82.1% in the UGT1A4 (rs6755571) A/C genotype versus +28.0% and +30.1% in the C/C genotype (p < 0.001 and p = 0.004, respectively). The UGT1A4 (rs6755571) A/C genotype may be an important risk factor for clinically-relevant serum transaminase elevations with 6-9 months of high-dose GTE supplementation among postmenopausal women. Understanding the genetic underpinnings of GTE-related hepatotoxicity may allow for a genetically-informed paradigm for therapeutic use of GTE.

Activation of Alternative Bilirubin Clearance Pathways Partially Reduces Hyperbilirubinemia in a Mouse Model Lacking Functional Ugt1a1 Activity

Bilirubin is a heme catabolite and Ugt1a1 is the only enzyme involved in the biological elimination of bilirubin. Partially functional or non-functional Ugt1a1 may result in neuronal damage and death due to the accumulation of unconjugated bilirubin in the brain. The understanding of the role of alternative bilirubin detoxification mechanisms that can reduce bilirubin toxicity risk is crucial for developing novel therapeutic strategies. To provide a proof-of-principle showing whether activation of alternative detoxification pathways could lead to life-compatible bilirubin levels in the absence of Ugt1a1 activity, we used Ugt1^−/− hyperbilirubinemic mice devoid of bilirubin glucuronidation activity. We treated adult Ugt1^−/− mice with TCPOBOP, a strong agonist of the constitutive androstane receptor (CAR). TCPOBOP treatment decreased plasma and liver tissue bilirubin levels by about 38%, and resulted in the transcriptional activation of a vast array of genes involved in bilirubin transport and metabolism. However, brain bilirubin level was unaltered. We observed ~40% degradation of bilirubin in the liver microsomes from TCPOBOP treated Ugt1^−/− mice. Our findings suggest that, in the absence of Ugt1a1, the activation of alternative bilirubin clearance pathways can partially improve hyperbilirubinemic conditions. This therapeutic approach may only be considered in a combinatorial manner along with other treatments.

Susceptibility Loci in SLC15A1, UGT1A3, and CWC27 Genes Associated with Bladder Cancer in the Northeast Chinese Population

Bladder cancer (BCa) is an increasingly severe clinical and public health issue. Therefore, we aim to investigate BCa susceptibility loci in the Chinese population. In this study, 487 BCa patients and 563 controls were recruited from the First Affiliated Hospital of China Medical University from July 2015 to September 2020. A total of ten single-nucleotide polymorphisms (SNPs) in solute carrier family 15 member 1 (SLC15A1), CWC27 spliceosome associated cyclophilin (CWC27), or UDP glucuronosyltransferase family 1 member A3 (UGT1A3) genes were genotyped. The associations between the candidate SNPs and BCa were analyzed using genotype and haplotype analysis. The results demonstrated that Rs4646227 of SLC15A1 has a significant association with BCa. The patients with CG (OR =2.513, p < 0.05) and GG (OR =2.859, p < 0.05) genotypes had an increasing risk of BCa compared with the CC genotype. For the CWC27 gene, genotypic frequency analysis revealed that the GT or TT genotype of rs2042329 and the CT or TT genotype of rs1870437 were more frequent in BCa patients than those in the control group, indicating that these genotypes were associated with a higher risk of BCa (all p < 0.05). Haplotypes of SLC15A1, UGT1A3, and CWC27 genes found that the C-C-C haplotype of SLC15A1 was associated with a lower risk of BCa while the C-G-C haplotype was associated with a higher risk. For the UGT1A3 gene, a moderate protective effect was observed with the most frequent T-T-C haplotype, and for the CWC27 gene, most of the haplotypes showed no association with BCa, except the G-G-C-T haplotype (order of SNPs: rs2042329-rs7735338-rs1870437-rs2278351, OR =0.81, p =0.038). In sum, this study indicated that rs2042329 and rs1870437 in the CWC27 gene and rs4646227 in the SLC15A1 gene are independent indicators for BCa risk in Chinese people. Further large-scale studies are required to validate these findings. Also, this study provided the theoretical basis for developing new therapeutic drug targeting of BCa.

The influence of UGT1A1 polymorphisms on modified FOLFIRINOX dose in double-variant-type patients with advanced pancreatic cancer

BACKGROUND

UGT1A1 polymorphisms should be considered when using irinotecan-containing regimens, especially in patients with a double-variant-type (DV), including homozygous for UGT1A1*28 and UGT1A1*6 and heterozygous for both UGT1A1*28 and UGT1A1*6. We investigated the safety and efficacy of modified FOLFIRINOX (mFOLFIRINOX) (irinotecan 80 mg/m2) in patients having DV.

METHODS

Patients with advanced pancreatic cancer who had received FOLFIRINOX between January 2015 and December 2019 were included in this study. Non-DV patients received the standard mFOLFIRINOX (irinotecan 150 mg/m2) as first-line (non-DV1) or second-line therapy (non-DV2); however, DV patients received mFOLFIRINOX (irinotecan 80 mg/m2) as the second-line therapy (DV2). We retrospectively evaluated the safety and efficacy of the lowered irinotecan dose in the DV2 group relative to the non-DV1 (safety) or non-DV2 (safety and efficacy) groups.

RESULTS

A total of 235 patients were eligible for this study with 118 patients in the non-DV1, 106 in the non-DV2, and 11 in the DV2 groups. Major grade 3-4 adverse events were neutropenia (33.9, 31.1, and 18.2%) and febrile neutropenia (6.8, 3.8, and 9.1%) in the non-DV1, non-DV2, and DV2 groups, respectively. The median progression-free survival was 3.4 months in the non-DV2 group, and 4.4 months in the DV2 group. The overall survival from the date of starting second-line chemotherapy was 8.8 months in the non-DV2 group and 11.5 months in the DV2 group.

CONCLUSIONS

Based on our findings, the safety and efficacy of mFOLFIRINOX (irinotecan 80 mg/m2) in DV patients were comparable with the standard mFOLFIRINOX (irinotecan 150 mg/m2) in non-DV patients.