Aims: This study aimed to investigate the impact of genetic polymorphisms of thiopurine methyltransferase (TPMT) and NUDT15 on pharmacokinetics profile of mercaptopurine in healthy adults in China. Methods: Blood samples were obtained from 45 healthy adult volunteers who were administered azathioprine. Genomic DNA was extracted and sequenced for TPMT and NUDT15. The plasma concentrations of 6-mercaptopurine (6-MP) were determined by ultra-performance liquid chromatography-tandem mass spectrometry. Finally, pharmacokinetic parameters were calculated based on the time-concentration curve. Results: Among the 45 healthy adult volunteers enrolled in the study, two TPMT allelic variants and three NUDT15 allelic variants were detected. In total, six genotypes were identified, including TPMT*1/*1&NUDT15*1/*1, TPMT*1/*1&NUDT15*1/*2, TPMT*1/*1&NUDT15*1/*9, TPMT*1/*1&NUDT15*2/*5, TPMT*1/*6&NUDT15*1/*2, and TPMT*1/*3&NUDT15*1/*2. The results indicated that Area Under Curve (AUC) of 6-MP in volunteers with TPMT*1/*3&NUDT15*1/*2 and TPMT*1/*6&NUDT15*1/*2 were 1.57-1.62-fold higher than in individuals carrying the wild type (TPMT*1/*1&NUDT15*1/*1). Compared with wild type, the half-life (T1/2) of TPMT*1/*6&NUDT15*1/*2 was extended by 1.98 times, whereas T1/2 of TPMT*1/*3&NUDT15*1/*2 decreased by 67%. The maximum concentration (Cmax) of TPMT*1/*3&NUDT15*1/*2 increased significantly by 2.15-fold, whereas the corresponding clearance (CL/F) decreased significantly by 58.75%. Conclusion: The findings of this study corroborate the notion that various genotypes of TPMT and NUDT15 can impact the pharmacokinetics of mercaptopurine, potentially offering foundational insights for personalized mercaptopurine therapy.

BACKGROUND: Azathioprine (AZA) is a widely used immunosuppressant drug. Leukopenia is a serious adverse effect of the drug which often necessitates dose reduction or drug withdrawal. Predictors of leukopenia include genetic and nongenetic factors. Genetic polymorphism of AZA-metabolizing enzyme, thiopurine S-methyltransferase (TPMT) is well established. There is inconclusive evidence about the role of Nudix hydrolase (NUDT15) gene polymorphism. This case-control study assessed the association of genetic polymorphisms of NUDT15 and TPMT with leukopenia induced by AZA.
METHODS: Cases were patients on AZA who developed leukopenia (white blood cell count <4000/μl) within 1 year of treatment initiation that necessitated dose reduction or drug withdrawal. Age and gender-matched patients without leukopenia within 1 year of treatment with AZA served as controls. TPMT (3 loci: c238G to C, c460G to A, c719A to G) and NUDT15 (c 415C to T, rs116855232) genotyping were done using TPMT strip assay and polymerase chain reaction-restriction fragment length polymorphism, respectively. Genotype frequencies were noted, and the odds ratio was calculated to determine the association between genotypes and leukopenia.
RESULTS: Twenty-nine subjects (15 cases and 14 controls) were enrolled. Statistically significant differences were not observed in the TPMT genotype (*1/*1 and *1/*3C) (P = 0.23) between cases and controls. NUDT15 genotypes (*1/*1 and *1/*3) (P = 0.65) also showed no statistically significant difference between cases and controls.
CONCLUSIONS: The above genotypes do not appear to be associated with AZA-induced leukopenia in an eastern Indian population.

Inositol pyrophosphate 1,5-IP8 regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes pho1, pho84, and tgp1, via its action as an agonist of precocious termination of transcription of the upstream lncRNAs that repress PHO mRNA synthesis. 1,5-IP8 levels are dictated by a balance between the Asp1 N-terminal kinase domain that converts 5-IP7 to 1,5-IP8 and three inositol pyrophosphatases-the Asp1 C-terminal domain (a histidine acid phosphatase), Siw14 (a cysteinyl-phosphatase), and Aps1 (a Nudix enzyme). In this study, we report the biochemical and genetic characterization of Aps1 and an analysis of the effects of Asp1, Siw14, and Aps1 mutations on cellular inositol pyrophosphate levels. We find that Aps1\'s substrate repertoire embraces inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8. Aps1 displays a ~twofold preference for hydrolysis of 1-IP7 versus 5-IP7 and aps1∆ cells have twofold higher levels of 1-IP7 vis-à-vis wild-type cells. While neither Aps1 nor Siw14 is essential for growth, an aps1∆ siw14∆ double mutation is lethal on YES medium. This lethality is a manifestation of IP8 toxicosis, whereby excessive 1,5-IP8 drives derepression of tgp1, leading to Tgp1-mediated uptake of glycerophosphocholine. We were able to recover an aps1∆ siw14∆ mutant on ePMGT medium lacking glycerophosphocholine and to suppress the severe growth defect of aps1∆ siw14∆ on YES by deleting tgp1. However, the severe growth defect of an aps1∆ asp1-H397A strain could not be alleviated by deleting tgp1, suggesting that 1,5-IP8 levels in this double-pyrophosphatase mutant exceed a threshold beyond which overzealous termination affects other genes, which results in cytotoxicity.
OBJECTIVE: Repression of the fission yeast PHO genes tgp1, pho1, and pho84 by lncRNA-mediated interference is sensitive to changes in the metabolism of 1,5-IP8, a signaling molecule that acts as an agonist of precocious lncRNA termination. 1,5-IP8 is formed by phosphorylation of 5-IP7 and catabolized by inositol pyrophosphatases from three distinct enzyme families: Asp1 (a histidine acid phosphatase), Siw14 (a cysteinyl phosphatase), and Aps1 (a Nudix hydrolase). This study entails a biochemical characterization of Aps1 and an analysis of how Asp1, Siw14, and Aps1 mutations impact growth and inositol pyrophosphate pools in vivo. Aps1 catalyzes hydrolysis of inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8 in vitro, with a ~twofold preference for 1-IP7 over 5-IP7. aps1∆ cells have twofold higher levels of 1-IP7 than wild-type cells. An aps1∆ siw14∆ double mutation is lethal because excessive 1,5-IP8 triggers derepression of tgp1, leading to toxic uptake of glycerophosphocholine.

OBJECTIVE: Hematotoxicity is a life-threatening condition that has become the major cause of drug discontinuation in patients with acute lymphoblastic leukemia (ALL). The nudix hydrolase 15 (NUDT15) gene polymorphism (c.415C>T) is reported to have an association with the hematotoxicity of 6-mercaptopurine (6-MP) as maintenance therapy in patients with ALL. However, the prevalence of this genetic polymorphism in the Indonesian population is unknown. This study aimed to assess the frequency of NUDT15 polymorphism among Indonesian pediatric patients with ALL and its association with the hematotoxicity of 6-MP.
METHODS: A total of 101 stored DNA samples from pediatric patients with ALL receiving 6-MP treatment were used for genetic testing. Direct sequencing was conducted to determine the NUDT15 c.415C>T genotype. Chi-square or Fisher\'s exact test were employed to examine the association between the NUDT15 c.415C>T genotype and hematotoxicity.
RESULTS: All (100%) of the DNA samples from patients with ALL treated with 6-MP exhibited a homozygous variant of the NUDT15 c.415C>T genotype, 70.3% of which showed hematotoxicity to some extent. We found no significant differences in NUDT15 gene polymorphism among patients with ALL with different states of hematotoxicity.
CONCLUSIONS: The observed high frequency of NUDT15 c.415C>T in our study population might explain the elevated prevalence of 6-MP-associated hematotoxicity in pediatric patients with ALL within the Indonesian population. Our study provides new insight regarding the NUDT15 gene polymorphism and its relation to hematotoxicity. Further studies are required to determine the necessity of adjusting the initial dose of 6-MP for Indonesian pediatric patients with ALL.

Thiopurines, an effective therapy for Crohn\'s disease (CD), often lead to adverse events (AEs). Gene polymorphisms affecting thiopurine metabolism may predict AEs. This retrospective study in CD patients (n = 114) with TPMT activity > 5 Units/Red Blood Cells analyzed TPMT (c.238 G > C, c.460 G > A, c.719 A > G), ITPA (c.94 C > A, IVS2 + 21 A > C), and NUDT15 (c.415 C > T) polymorphisms. All patients received azathioprine (median dose 2.2 mg/kg) with 41.2% experiencing AEs, mainly myelotoxicity (28.1%). No NUDT15 polymorphisms were found, 7% had TPMT, and 31.6% had ITPA polymorphisms. AEs led to therapy modifications in 41.2% of patients. Multivariate analysis identified advanced age (OR 1.046, p = 0.007) and ITPA IVS2 + 21 A > C (OR 3.622, p = 0.015) as independent predictors of AEs. IVS2 + 21 A > C was also associated with myelotoxicity (OR 2.863, p = 0.021). These findings suggest that ITPA IVS2 + 21 A > C polymorphism and advanced age predict AEs during thiopurine therapy for CD with intermediate-normal TPMT activity.

BACKGROUND: Therapy with anti-cancer drugs remain the cornerstone of treating cancer. The effectiveness and safety of anti-cancer drugs vary significantly among individuals due to genetic factors influencing the drug response and metabolism. Data on the pharmacogenomic variations in Sri Lankans related to anti-cancer therapy is sparse. As current treatment guidelines in Sri Lanka often do not consider local pharmacogenomic variants, this study aimed to explore the diversity of pharmacogenomic variants in the Sri Lankan population to pave the way for personalized treatment approaches and improve patient outcomes.
METHODS: Pharmacogenomic data regarding variant-drug pairs of genes CYP2D6, DPYD, NUDT15, EPAS1, and XRCC1 with clinical annotations labelled as evidence levels 1A-2B were obtained from the Pharmacogenomics Knowledgebase database. Their frequencies in Sri Lankans were obtained from an anonymized database that was derived from 541 Sri Lankans who underwent exome sequencing at the Human Genetics Unit, Faculty of Medicine, University of Colombo. Variations in DPYD, NUDT15, and EPAS1 genes are related to increased toxicity to fluoropyrimidines, mercaptopurines, and sorafenib respectively. Variations in CYP2D6 and XRCC1 genes are related to changes in efficacy of tamoxifen and platinum compounds, respectively. Minor allele frequencies of these variants were calculated and compared with other populations.
RESULTS: MAFs of rs1065852 c.100 C > T (CYP2D6), rs3918290 c.1905 + 1G > A (DPYD), rs56038477 c.1236G > A (DPYD), rs7557402 c.1035-7 C > G (EPAS1), rs116855232 c.415 C > T (NUDT15*3), and rs25487 c.1196 A > G (XRCC1) were: 12.9% [95%CI:10.9-14.9], 1.5% [95%CI:0.8-2.2], 1.2% [95%CI:0.5-1.8], 37.7% [95%CI:34.8-40.6], 8.3% [95%CI:6.7-10.0], and 64.0% [95%CI:61.1-66.8], respectively. Frequencies of rs1065852 c.100 C > T (CYP2D6), rs7557402 c.1035-7 C > G (EPAS1), and rs25487 (XRCC1) were significantly lower in Sri Lankans, while frequencies of rs116855232 c.415 C > T (NUDT15*3) and rs56038477 c.1236G > A (DPYD) were significantly higher in Sri Lankans when compared to some Western and Asian populations.
CONCLUSIONS: Sri Lankans are likely to show lower toxicity risk with sorafenib (rs7557402 c.84,131 C > G) and, higher toxicity risk with fluoropyrimidines (rs56038477 c.1236G > A) and mercaptopurine (rs116855232 c.415 C > T), and reduced effectiveness with tamoxifen (rs1065852 c.100 C > T) and platinum compounds (rs25487). These findings highlight the potential contribution of these genetic variations to the individual variability in anti-cancer dosage requirements among Sri Lankans.

Acute lymphoblastic leukemia (ALL) is the most frequent pediatric cancer. 6-Mercaptopurine (6-MP) is a key component of ALL treatment. Its use, however, is also associated with adverse drug reactions, particularly myelosuppression. Thiopurine S-methyltransferase (TPMT) and, more recently, Nudix hydrolase 15 (NUDT15) deficiency, due to no-function variants in their respective genes, are well known for their role in the development of this toxicity. Two novel genetic variants, rs12199316 in TPMT and rs73189762 in the NUDT15 gene, were recently identified by targeted sequencing. The latter is particularly interesting because of its potential association with 6-MP intolerance. Here, we assessed the relationship of this variant with the risk of myelosuppression and 6-MP dose intensity in 275 patients treated with Dana Farber Cancer Institute ALL protocols at the Sainte Justine University Health Center. Carriers of the NUDT15 rs73189762 variant allele were at a higher risk of myelosuppression, as shown by absolute phagocyte count reduction during consolidation II and maintenance phases of therapy. Reduction in 6-MP dose intensity was observed in patients with both rs73189762 and known no-function variants in the NUDT15 and TPMT genes. This finding supports the initial observation and suggests that 6-MP dose reduction might be beneficial for individuals with this genotype combination.

This study evaluated the effectiveness of NUDT15 codon 139 genotyping in optimizing thiopurine treatment for inflammatory bowel disease (IBD) in Japan, using real-world data, and aimed to establish genotype-based treatment strategies.
A retrospective analysis of 4628 IBD patients who underwent NUDT15 codon 139 genotyping was conducted. This study assessed the purpose of the genotyping test and subsequent prescriptions following the obtained results. Outcomes were compared between the Genotyping group (thiopurine with genotyping test) and Non-genotyping group (thiopurine without genotyping test). Risk factors for adverse events (AEs) were analyzed by genotype and prior genotyping status.
Genotyping test for medical purposes showed no significant difference in thiopurine induction rates between Arg/Arg and Arg/Cys genotypes, but nine Arg/Cys patients opted out of thiopurine treatment. In the Genotyping group, Arg/Arg patients received higher initial doses than the Non-genotyping group, while Arg/Cys patients received lower ones (median 25 mg/day). Fewer AEs occurred in the Genotyping group because of their lower incidence in Arg/Cys cases. Starting with < 25 mg/day of AZA reduced AEs in Arg/Cys patients, while Arg/Arg patients had better retention rates when maintaining ≥ 75 mg AZA. Nausea and liver injury correlated with thiopurine formulation but not dosage. pH-dependent mesalamine reduced leukopenia risk in mesalamine users.
NUDT15 codon 139 genotyping effectively reduces thiopurine-induced AEs and improves treatment retention rates in IBD patients after genotype-based dose adjustments. This study provides data-driven treatment strategies based on genotype and identifies risk factors for specific AEs, contributing to a refined thiopurine treatment approach.

Tumor cells must rewire nucleotide synthesis to satisfy the demands of unbridled proliferation. Meanwhile, they exhibit augmented reactive oxygen species (ROS) production which paradoxically damages DNA and free deoxy-ribonucleoside triphosphates (dNTPs). How these metabolic processes are integrated to fuel tumorigenesis remains to be investigated. MYC family oncoproteins coordinate nucleotide synthesis and ROS generation to drive the development of numerous cancers. We herein perform a Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based functional screen targeting metabolic genes and identified nudix hydrolase 1 (NUDT1) as a MYC-driven dependency. Mechanistically, MYC orchestrates the balance of two metabolic pathways that act in parallel, the NADPH oxidase 4 (NOX4)-ROS pathway and the Polo like kinase 1 (PLK1)-NUDT1 nucleotide-sanitizing pathway. We describe LC-1-40 as a potent, on-target degrader that depletes NUDT1 in vivo. Administration of LC-1-40 elicits excessive nucleotide oxidation, cytotoxicity and therapeutic responses in patient-derived xenografts. Thus, pharmacological targeting of NUDT1 represents an actionable MYC-driven metabolic liability.

Borneol, camphor, and bornyl acetate are highly promising monoterpenoids widely used in medicine, flavor, food, and chemical applications. Bornyl diphosphate (BPP) serves as a common precursor for the biosynthesis of these monoterpenoids. Although bornyl diphosphate synthase (BPPS) that catalyzes the cyclization of geranyl diphosphate (GPP) to BPP has been identified in multiple plants, the enzyme responsible for the hydrolysis of BPP to produce borneol has not been reported. Here, we conducted in vitro and in vivo functional characterization to identify the Nudix hydrolase WvNUDX24 from W. villosa, which specifically catalyzes the hydrolysis of BPP to generate bornyl phosphate (BP), and then BP forms borneol under the action of phosphatase. Subcellular localization experiments indicated that the hydrolysis of BPP likely occurs in the cytoplasm. Furthermore, site-directed mutagenesis experiments revealed that four critical residues (R84, S96, P98, and G99) for the hydrolysis activity of WvNUDX24. Additionally, the functional identification of phosphatidic acid phosphatase (PAP) demonstrated that WvPAP5 and WvPAP10 were able to hydrolyze geranylgeranyl diphosphate (GGPP) and farnesyl diphosphate (FPP) to generate geranylgeranyl phosphate (GGP) and farnesyl phosphate (FP), respectively, but could not hydrolyze BPP, GPP, and neryl diphosphate (NPP) to produce corresponding monophosphate products. These findings highlight the essential role of WvNUDX24 in the first step of BPP hydrolysis to produce borneol and provide genetic elements for the production of BPP-related terpenoids through plant metabolic engineering and synthetic biology.