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Introduction: Acute lymphoblastic leukemia (ALL) is the most frequent pediatric leukemia; it can be defined according to chromosomic and genomic data. Cytogenetic analyses and determination of chromosomal numbers (such as hypo- or hyperdiploidy) and/or specific chromosomal rearrangements are basic for ALL classification and treatment. Even though cure rates of childhood ALL are at ~95%, pharmacogenetic aspects are of raising importance. Material and Methods: We have analyzed the literature for ALL subtypes, corresponding therapy options, and pharmacogenetic implications. Results: Data for ALL subtypes such as B-ALL, T-ALL, Ph-like ALL, DS-ALL, ETP-ALL, BCR-ABL1-like ALL are presented here. The gene polymorphism which lead to metabolizability of 6-MP are ITPA variants (94C>A) and IVS2+21A>C, in conjunction with TPMT (238G>C, TPMT*3B 460G>A and *3C 719A>G and NUDT15 (415C>T). For methotrexate metabolism gene polymorphisms are found for gene MTHFR as C677T and A1298C. Conclusion: In the last decade in many hospital laboratories, pharmacogenetic aspects gain more and more importance. Application of many molecular biology methods provided progress in treatment and diagnosis of ALL patients. Combination therapy is proposed as an alternative to single drug treatments.

This research investigates the usage of pipette tip micro solid phase extraction for the separation of 6-mercaptopurine of complicated matrices before its spectrophotometric detection. To overcome the non-selectivity of spectrophotometry, an ethylene glycol dimethacrylatebased molecularly imprinted polymer was prepared and applied as an adsorbent, which enabled selective and fast extraction of the analyte. To improve the transfer of the analyte to the adsorbent, a salting-out effect was employed by the addition of 300 mg of NaCl to the sample before performing microextraction. Variables affecting the microextraction of the protocol were investigated utilizing two ways one-factorat-a-time and response surface methodology, which showed good consistency with each other. Extraction parameters were optimized as pH of sample = 9.0, sample volume = 10 ml, amount of adsorbent = 2.0 mg, eluent = 250 µl of methanol:acetonitrile (1:5 v/v), and extraction and elution cycles of 10 and 12 times, respectively. The dynamic linear range of the protocol was 1.0-1000.0 µg l-1, with a limit of detection of 0.25 µg l-1. The method was compared with extraction by a non-imprinted polymer. The extraction efficiency of the analyte was obtained from 96.0% to 99.8%, by relative standard deviations better than 5.3%. The suggested technique was employed to determine 6-mercaptopurine in seawater and body fluid samples, and the results were validated by comparing them to a standard HPLC method. The whole analysis time, including microextraction, was about 25 min and to perform this method, the sole instrument required is a conventional spectrophotometer. [ABSTRACT FROM AUTHOR]

Background: 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. Methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Infertility is a frequent long-term adverse effect of cancer therapy for children. Compromised testicular functions in adolescence are frequent observations after chemotherapy and there are currently no well-established alternatives to avoid this damage. Antimetabolites such as 6-mercaptopurine (6-MP) are used to treat a variety of cancer; however, its treatment-associated adverse effects on the male reproductive functions are overlooked. Here, the molecular processes underlying 6-MP-induced male germ cell damage in juvenile Sprague–Dawley (SD) rats (3 weeks) have been investigated. Rats were administered with low (5 mg/kg), medium (10 mg/kg), and high (20 mg/kg) doses of 6-MP per orally either singly (1 week × 1 cycle) or intermittently (1 week treatment followed by 1 week remission period × 3 cycles). The toxicity was evaluated in terms of genotoxicity and testes- and sperm-related cellular and molecular parameters. Single cycle of exposure either produced mild or no toxic manifestations at the end of the 6th week. Intermittent cycles of exposure, particularly at the 10 and 20 mg/kg, decreased body and organ weights, increased micronucleated cells in the peripheral blood, induced oxidative/nitrosative stress, altered sperm chromatin quality, reduced serum testosterone and follicle stimulating hormone (FSH) levels, increased testicular structural aberrations, DNA damage, and apoptosis, and upregulated TNF-α expression and downregulated p-AMPK and β-catenin expressions. Conclusively, intermittent cycles of exposure at 10 and 20 mg/kg doses to the juvenile rats significantly induced oxidative stress, genotoxicity, and cellular and molecular perturbations in the testes and sperm of adult rats. [ABSTRACT FROM AUTHOR]

Introduction: Acute lymphoblastic leukemia (ALL) is the most frequent pediatric leukemia; it can be defined according to chromosomic and genomic data. Cytogenetic analyses and determination of chromosomal numbers (such as hypo- or hyperdiploidy) and/or specific chromosomal rearrangements are basic for ALL classification and treatment. Even though cure rates of childhood ALL are at ~95%, pharmacogenetic aspects are of raising importance. Material and Methods: We have analyzed the literature for ALL subtypes, corresponding therapy options, and pharmacogenetic implications. Results: Data for ALL subtypes such as B-ALL, T-ALL, Ph-like ALL, DS-ALL, ETP-ALL, BCR-ABL1-like ALL are presented here. The gene polymorphism which lead to metabolizability of 6-MP are ITPA variants (94C>A) and IVS2+21A>C, in conjunction with TPMT (238G>C, TPMT*3B 460G>A and *3C 719A>G and NUDT15 (415C>T). For methotrexate metabolism gene polymorphisms are found for gene MTHFR as C677T and A1298C. Conclusion: In the last decade in many hospital laboratories, pharmacogenetic aspects gain more and more importance. Application of many molecular biology methods provided progress in treatment and diagnosis of ALL patients. Combination therapy is proposed as an alternative to single drug treatments. [ABSTRACT FROM AUTHOR]

6‐Mercaptopurine (6MP) is commonly used in the treatment of acute lymphoblastic leukemia as an important agent in maintenance therapy. Despite its therapeutic benefits, 6MP has some limitations during therapy. Taking into account the disadvantages during 6MP therapy, there is a great need to create an appropriate delivery system for this drug. 6MP contains in its structure nitrogen and sulfur atoms capable of forming coordination compounds with metal ions, for example zinc. Therefore, in this work, we prepared biocompatible hydroxyapatite (HAp) doped with zinc ions, and used it as a carrier for 6MP. Doped HAp has not been used as a carrier for this drug before. The work proved that the prepared carrier‐drug system has a particle size of about 130 nm, which indicates its potential for intravenous delivery. In addition, in an acidic environment (imitating cancer cells), the carrier agglomerates allow targeted release of the drug. The drug is evenly distributed, which indicates that the doses released from it will always be comparable. The release of the drug in a neutral environment is long‐lasting in controlled doses, whereas in an acidic environment it is immediate. The obtained results indicate the high potential of the material in both slow‐release and cancer‐targeted release of 6MP. [ABSTRACT FROM AUTHOR]

BACKGROUND: Maintenance therapy for acute lymphoblastic leukemia (ALL) in young adults Includes a backbone of daily oral 6-mercaptopurine (6-MP) and weekly oral methotrexate (MTX). Oral 6-MP and MTX are associated with large interpersonal variations in drug bioavailability and tolerability and frequently cause adverse events. National Comprehensive Cancer Network guidelines recommend following dose modifications per the chosen treatment regimen, but data regarding the tolerability of oral chemotherapy and frequency of dose modifications during the maintenance phase in adults are lacking. OBJECTIVES: To describe real-world dose adjustments of MTX and 6-MP during the maintenance therapy in young adults, to describe the adverse events related to treatment with 6-MP and MTX, and to assess the incidence of relapse. METHODS: This was a single-center, retrospective, descriptive study of young adults with ALL. We reviewed the medical records of all patients aged 18 to 39 years who were initiated on standard-of-care treatment with CALGB 10403 (C10403) between January 1, 2015, and January 1, 2020, and received maintenance therapy. RESULTS: A total of 12 of the 13 included patients had adverse events requiring a dose adjustment. Overall, there were 130 dose adjustments. Dose interruptions most frequently resulted from grade >2 hepatotoxicity or grade >3 neutropenia. The agents were restarted at lower doses in approximately 50% of the cases, including 8 cases after the first episode of hematologic adverse events or hepatotoxicity. Dose escalations primarily occurred after previous interruption and resumption at a lower dose as a result of adverse events and were well tolerated, with a median of 15% increase per escalation. Of the 13 patients, 4 had disease relapse, 3 of which occurred during maintenance therapy. CONCLUSION: Adverse events leading to dose adjustments were common in the young adults with ALL who received maintenance treatment at our institution, but treatment modifications varied from recommendations in C10403, highlighting the challenges with tolerability and patient and physician protocol compliance in young adults. Additional studies that optimize monitoring, dose modifications, and maintenance dose intensity in adolescents and young adults are warranted. [ABSTRACT FROM AUTHOR]

A 13-year-old male undergoing maintenance chemotherapy with methotrexate and 6-mercaptopurine (6MP), for very high-risk B-cell acute lymphoblastic leukemia (ALL), presented with vomiting due to severe hypoglycemia with metabolic acidosis. While his laboratory values were concerning for a critically ill child, the patient was relatively well appearing. Hypoglycemia is a rare but serious side effect of 6MP with an unexpectedly variable presentation; therefore, a high index of suspicion is needed for its prompt detection and treatment. This patient also had severe metabolic acidosis, likely secondary to hypoglycemia, creating a serious clinical picture despite a well-appearing child. This example of incongruity between laboratory tests and clinical appearance adds nuance to the existing literature. Moreover, although 6MP-associated hypoglycemia is rare, it may be more prevalent than the literature suggests, as symptoms of hypoglycemia—nausea, vomiting, and somnolence—mirror common chemotherapy side effects. 6MP-induced hypoglycemia can be ameliorated with the addition of allopurinol to shunt metabolism in favor of the production of therapeutic metabolites over hepatotoxic metabolites. Additionally, a morning administration of 6MP and frequent snacks may also help to prevent hypoglycemia. Overall, this case adds to the literature of unusual reactions to 6MP including hypoglycemia in an older child without traditional risk factors. [ABSTRACT FROM AUTHOR]

Resumen: Introducción y objetivos: La leucopenia relacionada con tiopurina está asociada con polimorfismos en la tiopurina metiltransferasa (TPMT, por sus siglas en inglés) y con el gen NUDT15. Sin embargo, estos polimorfismos explican solo una fracción de la leucopenia relacionada con tiopurina. Nuestro objetivo fue estudiar el papel de un polimorfismo de pirofosfatasa inosina trifosfato (ITPA, por sus siglas en inglés) en pacientes con enfermedad inflamatoria intestinal (EII) y la leucopenia relacionada con tiopurina que no fue explicada por los polimorfismos de TPMT o NUDT15. Material y métodos: Reclutamos a pacientes consecutivos con EII tratados con tiopurinas (azatioprina o 6-mercaptopurina) entre enero del 2019 y marzo del 2020, en un centro de tercer nivel en el norte de la India. La presencia de polimorfismo en ITPA (C.94C>A) fue evaluada en todos los pacientes, junto con su asociación a la leucopenia relacionada con tiopurina. Resultados: De los 33 pacientes (de un total de 119 pacientes) que desarrollaron leucopenia, 8 presentaron polimorfismo en TPMT (n = 1) o NUDT15 (n = 7). De los 111 pacientes restantes, la edad promedio fue de 36.36 ± 13.54 años y 57 (51.3%) fueron varones. Veinticinco (21.01%) presentaron leucopenia no explicada. El polimorfismo en ITPA fue detectado en 4 (16%) pacientes del grupo de leucopenia no explicada y en 24 (27.9%) pacientes del grupo sin leucopenia (p = 0.228). La razón de momios para predecir la leucopenia con polimorfismo en ITPA fue de 0.4921 (IC 95%: 0.1520-1.5830; p = 0.234). Conclusión: El polimorfismo en ITPA (C.94C>A) fue frecuentemente detectado en la población de estudio, pero no fue predictivo para leucopenia en pacientes con EII en terapia con tiopurina. Abstract: Introduction and aim: Thiopurine-related leukopenia is associated with polymorphisms in the thiopurine methyltransferase (TPMT) and nucleoside diphosphate-linked moiety X type motif 15 (NUDT15) genes. However, those polymorphisms explain only a fraction of thiopurine-related leukopenia. Our aim was to study the role of an inosine triphosphate pyrophosphatase (ITPA) polymorphism in patients with inflammatory bowel disease (IBD) and thiopurine-related leukopenia that was unexplained by the TPMT and NUDT15 polymorphisms. Material and methods: We enrolled consecutive IBD patients on thiopurines (azathioprine or 6-mercaptopurine) from January 2019-March 2020, at a tertiary care center in North India. The presence of the ITPA (C.94C>A) polymorphism was evaluated in all patients, along with its association with thiopurine-related leukopenia. Results: Of the 33 patients (from a total of 119 patients) that developed leukopenia, 8 had the TPMT (n = 1) or NUDT15 (n = 7) polymorphism. Of the remaining 111 patients, their mean age was 36.36 ± 13.54 years and 57 (51.3%) were males. Twenty-five (21.01%) had unexplained leukopenia. The ITPA polymorphism was detected in 4 (16%) patients in the unexplained leukopenia group and 24 (27.9%) patients in the non-leukopenia group (P=.228). The odds ratio for predicting leukopenia with the ITPA polymorphism was 0.4921 (95% CI: 0.1520-1.5830; P=.234). Conclusion: The ITPA (C.94C>A) polymorphism was frequently detected in the study population but was not predictive for leukopenia in patients with IBD on thiopurine therapy.

Abstract A 6-year-old girl diagnosed with intermediate-risk acute lymphoblastic leukemia (ALL) presented with severe myelotoxicity and multiple infections during phase IB induction treatment with 6-mercaptopurine (6-MP). In the subsequent treatment phases, which included 6-MP, the patient continued to show bone marrow aplasia and neutropenia, necessitating numerous dose adjustments and interruptions. The recommended dose was eventually reduced to 5 %. A pharmacogenetic analysis, conducted in induction phase IB, detected three single-nucleotide polymorphisms (SNPs) of the thiopurine S-methyltransferase (TPMT) gene, and the phenotype of a normal metabolizer was observed. As a result of a second pharmacogenetic analysis, pathological polymorphisms were revealed in Nudix hydrolase 15 (NUDT15), which may explain the patient’s myelotoxicity. Hence, a pharmacogenetic analysis performed in advance would have been able to prevent her from suffering severe toxicity and/or treatment failure.

Objective: Chemotherapeutic drugs not only have a therapeutic effect, but also cause serious damage to healthy organs. In this study, we investigated on the possible efficacy of propolis (PS) on the sublingual gland tissues exposed to 6-mercaptopurine (6MR) in male rats. Materials and Methods: Twenty-eight Wistar albino rats were allocated to four groups: control (KON), PS, 6MR, 6MR+PS. At 12 days of trial, sublingual glands of all rats were immediately dissected and analysed using the stereological technique and histological examination. Results: Our findings revealed a significant increase in the total volume of stroma and significant decrease in the total volume of the total volumes of mucous acini, straited ducts, interlobular ducts, and intralobular ducts in the 6MR group than the KON group (p<0.05). A significant decrease was also found in the mucous cell number and the serous cell number in the 6MR group than the KON group (p<0.05). In the 6MR+PS group, we observed that the total volume of stroma, as well as the mucous cell number and the serous cell number were increased compared to the 6MR group (p<0.05). Besides, the total volumes of mucous acini, straited ducts, interlobular ducts, and intralobular ducts were significantly increased in the 6MR+PS group than the 6MR group (p<0.05). Conclusion: Our results showed that 6MR treatment caused toxicity in sublingual gland tissues, as well as PS application improved such changes in sublingual glands exposed to 6MR. [ABSTRACT FROM AUTHOR]

Cure rates in pediatric acute lymphoblastic leukemia (ALL) currently approach 90% in the developed world. Treatment involves 6-8 mo of intensive multi-drug chemotherapy followed by 24 mo of maintenance treatment (ALL-MT). The cornerstone of ALL-MT is the daily administration of oral 6-mercaptopurine (6MP), a purine analogue. 6MP is combined with weekly oral methotrexate (MTX), an antifolate drug, to augment therapeutic activity. Some protocols include additional chemotherapy drugs (such as vincristine and corticosteroids) during MT. The objective of ALL-MT is to ensure uninterrupted treatment at the highest tolerated doses of 6MP and MTX. This requires periodic adjustments of 6MP and MTX doses throughout treatment. Tolerance is determined through regular clinical assessments and careful monitoring of blood counts. Tolerated drug doses vary widely among patients, influenced by genetic and non-genetic factors, and require individualized dosing. Suboptimal treatment intensity in ALL-MT is associated with inferior outcomes and results from failure to treat at highest tolerated drug doses and/or interruptions in treatment due to non-adherence or toxicity. Management of MT thus requires close supervision to ensure treatment adherence, periodic drug dose modifications, and treatment to tolerance, while minimizing treatment interruptions due to toxicity. The review highlights these challenges and discusses approaches and strategies for the management of MT, focusing on the Indian context. [ABSTRACT FROM AUTHOR]

Postoperative recurrence (POR) is the rule in patients with Crohn's disease (CD), mitigated with prophylactic therapy. The evidence for therapeutic choice and timing of intervention is lacking. We aimed to compare the rates of POR in patients treated early with prophylactic 6-mercaptopurine (6-MP) or adalimumab. We conducted a prospective single-center randomized open-label clinical study in which patients in surgical remission following their first ileocecectomy were randomized to receive early treatment with 6-MP or adalimumab. Patients were followed up clinically every 3 months and underwent endoscopy at weeks 32 and 58 postoperatively. The primary endpoint was endoscopic recurrence (ePOR) at 1 year (week 58), defined as a Rutgeerts score ≥ i2. We enrolled 35 patients (25 males, mean age 35 ± 1.4 years, median disease duration 5 ± 6.1 years) following ileocecectomy. Of these, seven (20%) were current smokers and nine (26%) biologics-experienced. Patients allocated to adalimumab had significantly less ePOR than patients treated with 6MP at week 32 (21% vs. 69%, p = 0.004) and 58 (47% vs. 75%), (p = 0.03, HR = 0.39, 95% CI = 0.16–0.93). POR was associated with an increased diameter of the resected small bowel surgical specimen, lower baseline body mass index (BMI), increased week 18 fecal calprotectin, increased week 18 serum alanine aminotransferase and decreased week 18 hemoglobin level. Adalimumab was more effective than 6-MP in preventing ePOR. Increased operative small bowel diameter and lower postoperative BMI were associated with ePOR. At eighteen weeks, serum hemoglobin, ALT and fecal calprotectin levels were predictive of endoscopic disease recurrence. (ClinicalTrials.gov ID NCT01629628). [ABSTRACT FROM AUTHOR]

In this work, the straightforward synthesis of amphiphilic zwitterionic bioderived block copolymers (BCPs) using glutamic acid (Glu) and cholesterol (Chol) as building blocks are reported. The previously established Glu‐derivative NBoc‐Glu‐OtBu‐methacrylate (NBoc‐Glu‐OtBu‐MA) serves as hydrophobic precursor for the zwitterionic block, while a mostly unexplored cholesteryl‐derived methacrylate monomer (Chol‐MA) with increased side chain flexibility functions as the hydrophobic block. In the first step, NBoc‐Glu‐OtBu‐MA is polymerized via reversible addition‐fragmentation chain‐transfer (RAFT) polymerization. Afterward, the linear polymer is chain‐extended with Chol‐MA, yielding P(NBoc‐Glu‐OtBu‐MA)n‐b‐(Chol‐MA)m BCPs with varying block ratios. After deprotection under acidic conditions, polymers with a block weight ratio of 87:13 (Glu‐OH‐MA:Chol‐MA) readily assemble into polymeric nanoparticles (NPs) of a desirable size below 100 nm diameter, making them good candidates for biomedical applications. The experimental results are supported using computations of the partition coefficients and machine learning models for the prediction of the polymer densities of the different BCPs. In addition, high (up to 20 wt.%) loading of the hydrophobic anti‐cancer drug 6‐mercaptopurine (6‐MP) is achieved in these NPs during the assembly process. The cytostatic activity of 6‐MP NPs is demonstrated in vitro on MDA‐MB‐231 breast cancer cells. These results emphasize the potential of amphiphilic zwitterionic bioderived NPs for the delivery of hydrophobic drugs. [ABSTRACT FROM AUTHOR]

Simple Summary: Drugs used to treat cancer are most often very toxic. Taking their high doses may adversely affect the patient's health, as a result of which the therapy, instead of helping, harms. An example of such a drug is 6-mercaptopurine, described in this paper. Due to these negative properties, it is necessary to create such systems that would release the drug in a controlled manner only in the vicinity of diseased tissues. In this work, a drug carrier was prepared that releases the drug only in the acidic environment of cancer, due to which healthy tissues will not be exposed to it. Systems that release the drug only in an acidic environment have not been described before and the application potential of such a carrier is very large. Hydroxy double salts are layered materials that are considered to be biocompatible. For this reason, research has been initiated on the possibility of their use in drug delivery. Despite their use for several types of drugs, their potential for controlled release of mercaptopurine (MERC) has not been studied. In this work, the synthesized hydroxy double salt (HDS) material was used as a carrier for this drug for the first time. The effectiveness of HDS synthesis has been proven by such techniques as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Based on the FT-IR and energy-dispersive X-ray spectroscopy (EDS) results, the effectiveness of drug sorption was proven. The exact amount of drug retained was determined by the UV-Vis technique. The obtained results indicate that the drug is evenly distributed on the surface of the carrier, which is important during the controlled delivery of drugs. In the most important stage of the research, the effectiveness of drug release in response to changes in the pH of the environment was proven. The drug is not released into an environment that mimics healthy human tissues. It is released only after contact with the acidic environment that usually surrounds cancer cells. The low cellular toxicity of HDS and significant cytotoxic effect of HDS-MERC were confirmed by in vitro studies on MCF-7 human breast and DU145 prostate cancer cell lines and non-cancerous keratinocytes HaCaT. Interestingly, coupling with the HDS carrier increased the cytotoxic effect of MERC towards DU145 cells. Such an "intelligent" drug carrier for mercaptopurine has not been previously described in the literature. The obtained results indicate its great potential. [ABSTRACT FROM AUTHOR]

This study focuses on the use of thiopurines for treating inflammatory bowel diseases (IBD). These drugs undergo enzymatic changes within the body, resulting in active and inactive metabolites that influence their therapeutic effects. The research examines the role of genetic polymorphisms in the enzyme thiopurine S-methyltransferase (TPMT) in predicting the therapeutic response and adverse effects of thiopurine treatment. The TPMT genotype variations impact the individual responses to thiopurines. Patients with reduced TPMT activity are more susceptible to adverse reactions (AEs), such leukopenia, hepatotoxicity, pancreatitis, and nausea, which are common adverse effects of thiopurine therapy. The therapeutic monitoring of the metabolites 6-thioguanine nucleotides (6-TGN) and 6-methyl mercaptopurine (6-MMP) is proposed to optimize treatment and minimize AEs. Patients with higher 6-TGN levels tend to have better clinical responses, while elevated 6-MMP levels are linked to hepatotoxicity. Genotyping for TPMT before or during treatment initiation is suggested to tailor dosing strategies and enhance treatment efficacy while reducing the risk of myelosuppression. In conclusion, this study highlights the importance of considering genetic variations and metabolite levels in optimizing thiopurine therapy for IBD patients, focusing on balance therapeutic efficacy with the prevention of adverse effects and contributing to personalized treatment and better patient outcomes. [ABSTRACT FROM AUTHOR]

Background: Childhood acute lymphoblastic leukemia (ALL) maintenance therapy with oral 6-mercaptopurine (6-MP) and methotrexate prevents leukemic relapse by acting against residual lymphoblasts. Non-adherence to oral maintenance therapy significantly increases ALL relapse risk. The levels of intracellular 6-MP metabolites erythrocyte incorporated (ery-) thioguanine nucleotides (ery-TGN) and methylated 6-MP metabolites (ery-MeMP) can be used to evaluate adherence to 6-MP, however, little is known on their short-term pharmacokinetics. The aim of this study was to assess the changes between trough levels and the levels at 2-hours after 6-MP intake when the 6-MP levels in plasma is expected to have peaked. Materials and methods: Ten ALL patients with stable 6-MP dose were prospectively included. Two blood samples were collected for ery-TGN and ery-MeMP analysis (before 6-MP intake and 2 h after). Results: The median trough ery-TGN was 173 (range 126–299) nmol/mmol hemoglobin (HGB), and 2 h after 6-MP intake the median level was 175 (range 120–293) nmol/mmol HGB. For ery-MeMP, the median trough and 2 h-concentrations were 9 239 (range 1 278–19 645) nmol/mmol HGB and 9 216 (range 1 215–19 519) nmol/mmol HGB, respectively. The median absolute percentual change for both ery-TGN and ery-MeMP were not statistically different from 0, p = 0.28 and p = 0.06, respectively. Conclusions: Intracellular 6-MP metabolites, ery-MeMP and ery-TGN, remain stable 2 h after oral 6-MP intake in patients with a stable 6-MP dose. This data support that blood samples may be used to assess patient adherence irrespective of the timing of 6-MP intake.

Antibody inhibitors that block PD‐1/PD‐L1 interaction have been approved for oncological clinics, yielding impressive treatment effects. Small molecules inhibiting PD‐1 signalling are at various stages of development, given that small molecular drugs are expected to outperform protein drugs in several ways. Currently, a significant portion of these small molecular inhibitors achieve this purpose by binding to a limited region of the PD‐L1 protein, thereby limiting the choice of chemical structures. Alternative strategies for developing small‐molecular PD‐1 inhibitors are urgently needed to broaden the choice of chemical structures. Here, we report that 6‐mercaptopurine (6‐MP) inhibits PD‐1 signalling, activates T cell function in vitro and in vivo and shrinks tumours by activating cytotoxic T cells. Mechanistically, 6‐MP potently inhibited PD‐1 signalling by blocking the recruitment of SHP2 by PD‐1. Considering that 6‐MP is a chemotherapeutic agent already approved by the FDA for childhood leukaemia, our work revealed a novel anti‐tumour mechanism for this drug and suggests that 6‐MP warrants further clinical evaluation for other tumour types. [ABSTRACT FROM AUTHOR]

Three ruthenium polypyridyl complexes of the type [Ru(N^N)2(6MP)](PF6) where 6MP = 6-mercaptopurine monohydrate; and N^N = 2,2′-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2) and dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq, 3) have been prepared and characterized by analytical and spectroscopic methods. The distorted octahedral geometry crystal structure of complex 1 was determined by single-crystal X-ray crystallography. FT-IR, UV–Vis, and elemental analysis were employed for structural elucidation. Theoretical modelling of the compounds was carried out for electronic property structure investigation along with experimental application as potential chemotherapeutic drug for antimicrobial agents and free radical scavenger. The experimental and theoretical vibrational wavenumbers of the synthesized compounds were compared and observed to be in good agreement. Density functional theory (DFT) at the ωB97XD/gen/def2-SVP/LanL2DZ level of theory was further utilized to investigate the frontier molecular orbitals, and the natural bond orbital (NBO) analysis for the investigation of the bonding interactions of the studied compounds. 1 with energy gap of 4.971 eV possessed higher stability followed by 2 with energy gap of 4.937 eV and 3 with energy gap of 4.756 eV. The natural bond analysis studies reveal that 3 with value 412.24 kcal/mol possessed a higher second-order perturbation energy than 2 (262.10 kcal/mol) and 1 (253.97 kcal/mol). The molecular docking approach reveals that all the studied compounds and ligands are found to have an excellent antibacterial and outstanding antifungal inhibitory activity which is in tandem with results from the in vitro antibacterial and antifungal activities. The order of the binding affinities for the studied compounds and the standard drugs is 2(− 10.8 kcal/mol) > 3(− 10.5 kcal/mol) > 1(− 9.8 kcal/mol) > standard drug (− 7.5 kcal/mol). [ABSTRACT FROM AUTHOR]

Macrophage activation syndrome is a life-threatening syndrome of uncontrolled immune activation with variable clinical presentation making early diagnosis difficult. It is often manifested by the development of multi-organ failure due to systemic inflammatory response. Patients with ulcerative colitis (UC) on purine antimetabolites are at high risk for severe myelosuppression due to the mechanism of thiopurine toxicity which potentially contributes to the development of macrophage activation syndrome. We present a case of a 39-year-old woman with a 2-year history of UC previously treated with 6-mercaptopurine (6-MP) and recent COVID-19 infection, who was admitted to our emergency department for C. difficile infection and subsequently developed macrophage activation syndrome. This case report also raises the question of whether abrupt discontinuation of 6-MP may have contributed to the worsening of the patient's symptoms of underlying hemophagocytic lymphohistiocytosis (HLH) and her rapid deterioration. Both macrophage activation syndrome and COVID-19 infection can produce a large number of pro-inflammatory cytokines termed "cytokine storm," but a pro-inflammatory cytokine panel breakdown helps to differentiate between the two. Our case report emphasizes the importance of close monitoring of patients on purine antimetabolite therapy who present with signs and symptoms of systemic toxicity. [ABSTRACT FROM AUTHOR]

A 6-year-old girl diagnosed with intermediate-risk acute lymphoblastic leukemia (ALL) presented with severe myelotoxicity and multiple infections during phase IB induction treatment with 6-mercaptopurine (6-MP). In the subsequent treatment phases, which included 6-MP, the patient continued to show bone marrow aplasia and neutropenia, necessitating numerous dose adjustments and interruptions. The recommended dose was eventually reduced to 5 %. A pharmacogenetic analysis, conducted in induction phase IB, detected three single-nucleotide polymorphisms (SNPs) of the thiopurine S-methyltransferase (TPMT) gene, and the phenotype of a normal metabolizer was observed. As a result of a second pharmacogenetic analysis, pathological polymorphisms were revealed in Nudix hydrolase 15 (NUDT15), which may explain the patient’s myelotoxicity. Hence, a pharmacogenetic analysis performed in advance would have been able to prevent her from suffering severe toxicity and/or treatment failure. [ABSTRACT FROM AUTHOR]

6-Mercaptopurine (6-MP) is a chemotherapeutic agent with inadequate efficacy due to its poor aqueous solubility and limited bioavailability. Turmeric oil is a naturally occurring bioactive substance obtained from the rhizomes of Curcuma longa Linn that has well-known antiproliferative activities. The aim of this study was to develop a 6-MP-loaded turmeric oil-based self-nanoemulsifying drug delivery system (SNEDDS) to improve the anticancer activity of 6-MP. Turmeric oil was extracted and used in a range of 15–25% to develop SNEDDS formulations utilizing tween 80 and dimethyl sulfoxide as the surfactant and cosurfactant, respectively. The size, charge, and effect of the formulations on the viability against HepG2 and MCF-7 cell models, as well as the apoptosis and cell cycle, were analyzed. The prepared SNEDDS formulations were in the size range of 425.7 ± 7.4–303.6 ± 19.3 nm, using a polydispersity index of 0.429–0.692 and electronegative surface charges. Moreover, 6-MP-loaded SNEDDS with 15% turmeric oil content (F1) showed smaller particle sizes and a noticeable antiproliferative activity against both cell line models. Also, F1 showed a higher rate of late apoptosis than the pure drug and the corresponding non-medicated formulation. A morphological study revealed significant changes in the HepG2 cells compared to untreated cells. More cells halted in the S phase, and a marked decrease in the proportions of cells in the G1/G0 phase was observed when using SNEDDS formulation compared to pure drug. Thus, SNEDDS formulation is a promising drug delivery system for improving the antiproliferative activity of 6-MP, especially when turmeric oil is incorporated. [ABSTRACT FROM AUTHOR]

6-Mercaptopurine (6-MCP) is an antiproliferative purine analog used in acute lymphoblastic leukemia, non-Hodgkin lymphoma, and inflammatory bowel disease (Crohn's disease, ulcerative colitis). Although 6-MCP has the great therapeutic potential for cancer and immunosuppressant-related diseases, 6-MCP is not readily soluble in water, presents a high first-pass effect, short half-life (0.5–1.5 h), and implies a low bioavailability (16%). On the contrary, solid lipid nanoparticles (SLNs) are prepared from solid lipids at room temperature and body temperature. In this study, SLNs were prepared w/o/w double emulsion-solvent evaporation method using Precirol ATO5 as matrix lipid. In the emulsion stabilization, surfactant (Tween 80) and polymeric stabilizer (polyvinyl alcohol [PVA]) were used. Two group formulations using Tween 80 and PVA were compared in terms of particle size, polydispersity index, zeta potential encapsulation efficiency%, and process yield%. Differential calorimetric analysis and release properties were examined for optimum formulation, and release kinetics were calculated. According to studies, sustained release was obtained with SLNs by the Korsmayer–Peppas kinetic model. The in vitro cytotoxicity studies were performed on the hepatocarcinoma (HEP3G) cell line. According to the results, successful SLN formulations were produced, and PVA was found best stabilizer. Optimum formulation exhibited significantly higher cytotoxic effects on HEP3G than on pure 6-MCP. These results demonstrated that solid lipid nanodrug delivery systems have great potential for formulation of 6-MCP. [ABSTRACT FROM AUTHOR]

Mercaptopurine is one of the drugs used in the treatment of acute lymphoblastic leukemia. A problem with mercaptopurine therapy is its low bioavailability. This problem can be solved by preparing the carrier that releases the drug in lower doses but over a longer period of time. In this work, polydopamine-modified mesoporous silica with adsorbed zinc ions was used as a drug carrier. SEM images confirm the synthesis of spherical carrier particles. The particle size is close to 200 nm, allowing for its use in intravenous delivery. The zeta potential values for the drug carrier indicate that it is not prone to agglomeration. The effectiveness of drug sorption is indicated by a decrease in the zeta potential and new bands in the FT-IR spectra. The drug was released from the carrier for 15 h, so all of the drug can be released during circulation in the bloodstream. The release of the drug from the carrier was sustained, and no 'burst release' was observed. The material also released small amounts of zinc, which are important in the treatment of the disease because these ions can prevent some of the adverse effects of chemotherapy. The results obtained are promising and have great application potential. [ABSTRACT FROM AUTHOR]

Recently, the main interest of analytical chemistry researchers has been the development of green analytical methods to minimize harmful effects on the environment and natural life. Therefore, an RP‐HPLC method was developed and assessed regarding its greenness criteria using three greenness assessment tools: an analytical eco‐scale, an analytical greenness metric approach and a green analytical procedure index. This method aims to separate and quantitatively determine three co‐administered drugs, namely pyridostigmine bromide (PYR), 6‐mercaptopurine (MRC) and prednisolone (PRD), in their tertiary mixture and spiked human plasma. These drugs are co‐administered to manage myasthenia gravis autoimmune disease. The separation was done using a C18 column and a gradient elution of a mixture of 0.1% H3PO4 aqueous solution (pH 2.3) and methanol. The flow rate was adjusted to 1 ml/min and detection was done at 254 (for PYR and PRD) and at 330 nm (for MRC). The lower limits of quantitation were 15, 2, and 5 μg/ml for PYR, MER and PRD, respectively. Linear correlations were obtained and found to be near 1. In addition, the proposed method was validated according to the US Food and Drug Administration's instructions, and the results proved its success to determine the three studied drugs in their tertiary mixture and spiked human plasma. [ABSTRACT FROM AUTHOR]

Abstract Background As a promising strategy to overcome the therapeutic disadvantages of 6-mercaptopurine (6MP), we proposed the encapsulation of 6MP in chitosan nanoparticles (CNPs) to form the 6MP-CNPs complexes. The encapsulation was followed by the loading of complexes on gold nanoparticles (AuNPs) to generate a novel 6MP-CNPs-AuNPs nanocomposite to facilitate the chemo-photothermal therapeutic effect. Methods CNPs were produced based on the ionic gelation method of tripolyphosphate (TPP). Moreover, 6MP-CNPs composite were prepared by the modified ionic gelation method and then loaded on AuNPs which were synthesized according to the standard wet chemical method using trisodium citrate as a reducing and capping agent. The synthesized nanocomposites were characterized by UV–VIS spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The potential cytotoxicity of the prepared nanocomposites on MCF7 cell line was carried out using Sulphorhodamine-B (SRB) assay. Results Optimization of CNPs, 6MP-CNPs, and 6MP-CNPs-AuNPs revealed 130 ± 10, 200 ± 20, and 25 ± 5 nm particle size diameters with narrow size distributions and exhibited high stability with zeta potential 36.9 ± 4.11, 37, and 44.4 mV, respectively. The encapsulation efficiency of 6MP was found to be 57%. The cytotoxicity of 6MP-CNPs and 6MP-CNPs-AuNPs on breast cell line MCF7 was significantly increased and reached IC50 of 9.3 and 8.7 µM, respectively. The co-therapeutic effect of the nanocomposites resulted in an improvement of the therapeutic efficacy compared to the individual effect of chemo- and photothermal therapy. Irradiation of 6MP-CNPs and 6MP-CNPs-AuNPs with a diode laser (DPSS laser, 532 nm) was found to have more inhibition on cell viability with a decrease in IC50 to 5 and 4.4 µM, respectively. Conclusion The Chemo-Photothermal co-therapy treatment with novel prepared nanocomposite exhibits maximum therapeutic efficacy and limits the dosage-related side effects of 6MP. Graphical Abstract

Colon cancer is a significant health concern. The development of effective drug delivery systems is critical for improving treatment outcomes. In this study, we developed a drug delivery system for colon cancer treatment by embedding 6-mercaptopurine (6-MP), an anticancer drug, in a thiolated gelatin/polyethylene glycol diacrylate hydrogel (6MP-GPGel). The 6MP-GPGel continuously released 6-MP, the anticancer drug. The release rate of 6-MP was further accelerated in an acidic or glutathione environment that mimicked a tumor microenvironment. In addition, when pure 6-MP was used for treatment, cancer cells proliferated again from day 5, whereas a continuous supply of 6-MP from the 6MP-GPGel continuously suppressed the survival rate of cancer cells. In conclusion, our study demonstrates that embedding 6-MP in a hydrogel formulation can improve the efficacy of colon cancer treatment and may serve as a promising minimally invasive and localized drug delivery system for future development. [ABSTRACT FROM AUTHOR]

A 13-year-old male undergoing maintenance chemotherapy with methotrexate and 6-mercaptopurine (6MP), for very high-risk B-cell acute lymphoblastic leukemia (ALL), presented with vomiting due to severe hypoglycemia with metabolic acidosis. While his laboratory values were concerning for a critically ill child, the patient was relatively well appearing. Hypoglycemia is a rare but serious side effect of 6MP with an unexpectedly variable presentation; therefore, a high index of suspicion is needed for its prompt detection and treatment. This patient also had severe metabolic acidosis, likely secondary to hypoglycemia, creating a serious clinical picture despite a well-appearing child. This example of incongruity between laboratory tests and clinical appearance adds nuance to the existing literature. Moreover, although 6MP-associated hypoglycemia is rare, it may be more prevalent than the literature suggests, as symptoms of hypoglycemia—nausea, vomiting, and somnolence—mirror common chemotherapy side effects. 6MP-induced hypoglycemia can be ameliorated with the addition of allopurinol to shunt metabolism in favor of the production of therapeutic metabolites over hepatotoxic metabolites. Additionally, a morning administration of 6MP and frequent snacks may also help to prevent hypoglycemia. Overall, this case adds to the literature of unusual reactions to 6MP including hypoglycemia in an older child without traditional risk factors.

Background. 6-mercaptopurine (6-MP) is a drug that is included in the treatment protocols for children and adults with acute lymphoblastic leukemias/lymphomas (ALL/LBL). It is known that individual differences in 6-MP tolerance can be explained by the TPMT and NUDT15 polymorphisms.Aim. To determine 6-MP toxicity profile in adult patients with Ph-negative ALL/LBL treated by ALL-2016 protocol, depending on the TPMT and NUDT15 polymorphisms.Materials and methods. The study included 54 adult patients with Ph-negative ALL/LBL (40 male and 14 female). The median age was 31 (18-51) years. T-ALL/LBL was diagnosed in 29 patients, B-ALL/LBL - in 22, acute leukemia with a mixed immunophenotype - in 3. All patients received treatment according to the multicenter study ALL-2016 (ClinicalTrials.gov, NCT03462095). polymorphisms in NUDT15 (*2, *3) and TPMT (*2, *3A, *3B, *3C) genes were detected using the allele-specific real-time polymerase chain reaction. Genomic DNA was extracted from patients peripheral blood samples. On the induction and consolidation therapy by the protocol, the received and proper 6-MP doses were calculated for all the patients. Drug toxicity was evaluated based on clinical and laboratory data.Results. TPMT and NUDT15 polymorphisms were detected in 11 (20 %) patients, more often in B-ALL - 7 (32 %) of 22 (p 0.05).Conclusion. There were no differences in the received dose of 6-MP and the incidence of toxicity in adult patients between Ph-negative ALL/LBL with or without TPMT and NUDT15 polymorphisms treated according to ALL-2016 protocol (p >0.05). further studies including evaluation of 6-MP metabolites concentrations are required for a more complete understanding of the metabolism of this drug.

Abstract Background A critical challenge in current acute lymphoblastic leukemia (ALL) therapy is treatment intensification in order to reduce the relapse rate in the subset of patients at the highest risk of relapse. The year-long maintenance phase is essential in relapse prevention. The Thiopurine Enhanced ALL Maintenance (TEAM) trial investigates a novel strategy for ALL maintenance. Methods TEAM is a randomized phase 3 sub-protocol to the ALLTogether1 trial, which includes patients 0–45 years of age with newly diagnosed B-cell precursor or T-cell ALL, and stratified to the intermediate risk-high (IR-high) group, in 13 European countries. In the TEAM trial, the traditional methotrexate (MTX)/6-mercaptopurine (6MP) maintenance backbone (control arm) is supplemented with low dose (2.5–12.5 mg/m2/day) oral 6-thioguanine (6TG) (experimental arm), while the starting dose of 6MP is reduced from 75 to 50 mg/m2/day. A total of 778 patients will be included in TEAM during ~ 5 years. The study will close when the last included patient has been followed for 5 years from the end of induction therapy. The primary objective of the study is to significantly improve the disease-free survival (DFS) of IR-high ALL patients by adding 6TG to 6MP/MTX-based maintenance therapy. TEAM has 80% power to detect a 7% increase in 5-year DFS through a 50% reduction in relapse rate. DFS will be evaluated by intention-to-treat analysis. In addition to reducing relapse, TEAM may also reduce hepatotoxicity and hypoglycemia caused by high levels of methylated 6MP metabolites. Methotrexate/6MP metabolites will be monitored and low levels will be reported back to clinicians to identify potentially non-adherent patients. Discussion TEAM provides a novel strategy for maintenance therapy in ALL with the potential of improving DFS through reducing relapse rate. Potential risk factors that have been considered include hepatic sinusoidal obstruction syndrome/nodular regenerative hyperplasia, second cancer, infection, and osteonecrosis. Metabolite monitoring can potentially increase treatment adherence in both treatment arms. Trial registration EudraCT, 2018–001795-38. Registered 2020-05-15, Clinicaltrials.gov , NCT04307576 . Registered 2020-03-13, https://clinicaltrials.gov/ct2/show/NCT04307576

Background Combination therapy with thiopurines and anti-tumor necrosis factor (TNF) is superior to monotherapy in Crohn's disease (CD) and ulcerative colitis (UC). The optimal dose of thiopurines in combination therapy remains unclear. We investigated the impact of thiopurine dose in combination therapy on outcomes in inflammatory bowel disease (IBD). Methods This was a single-center, retrospective study of patients with IBD treated with thiopurine and anti-TNF combination therapy between 1/2012 and 11/2020. A therapeutic dose of thiopurines was defined as =1 mg/kg for 6-mercaptopurine and =2 mg/kg for azathioprine. The primary outcome was anti-drug antibody (ADA) formation in patients on a therapeutic thiopurine dose vs. a lower thiopurine dose group. Secondary outcomes included steroid-free clinical remission, endoscopic healing (absence of ulcers/erosions in CD and Mayo endoscopic score =1 for UC), and normal serum C-reactive protein (CRP) in patients who were on combination therapy. Results A total of 108 patients were included (median age 31.5 years; 58.3% male). A therapeutic dose of thiopurine was used in 19%. In the therapeutic thiopurine dose group, 23.8% developed ADA vs. 29.9% (P=0.58) in the lower dose group. No significant differences were noted between the therapeutic and lower dose thiopurine groups in terms of steroid-free clinical remission (57.1% vs. 60.9%, P=0.75), endoscopic healing (55% vs. 60%, P=0.69), and normal CRP (52.4% vs. 52.9%, P=0.27). Conclusion In our cohort of patients with IBD on anti-TNF combination therapy, thiopurine dose was not associated with significant differences in anti-TNF immunogenicity and clinical outcomes. [ABSTRACT FROM AUTHOR]

Aim: Cancer is one of the most cause of deaths in worldwide. 6-mercaptopurine (6-MP) is successfully to treat leukemia. In recent years, 6-MP has remarkable properties for treating solid tumors. The aim of this study is to radiolabel 6-MP with [99mTc]Tc under appropriate conditions to develop tumor scintigraphic agent. Methods: In this work, 6-MP was radiolabeled using [99mTc]Tc radionuclide, and quality control experiment of [99mTc]Tc-6-MP were assessed via radioactive thin layer chromatography (RTLC). Also, the effect of critical parameters affecting the radiolabeling efficiency (reducing and antioxidant agent, incubation time, pH value, radiation dose) was evaluated. Then, the stability and lipophilicity tests of [99mTc]Tc-6-MP was performed. Results: According to the results, [99mTc]Tc-6-MP was prepared with over 93% labeling efficiency by a novel, easy, and quick direct method with 15-min incubation time at pH 7. To achieve the best radiolabeling condition; 0.5 mg.mL-1 of 6-MP solution, 250 μg of stannous tartrate (reducing agent), 0.050 mg ascorbic acid (antioxidant agent), and 37 MBq [99mTc]Tc was used. The RTLC studies indicated that [99mTc]Tc-6-MP is stable up to 6-h in room temperature. The logP of the [99mTc]Tc-6-MP were found to be -0.021 ± -0.001. Conclusions: The obtained results showed that radiolabeled 6-MP may be a promising tumor diagnostic agent. Further studies are in progress in order to evaluate tumor cell binding capacity and biodistribution of the complex in experimental animals. [ABSTRACT FROM AUTHOR]

Patients diagnosed with acute lymphoblastic leukemia (ALL) bearing t(4;11)/MLL-AF4 have aggressive clinical features, poor prognosis and there is an urgent need for new therapies to improve outcomes. Panobinostat (LBH589) has been identified as a potential therapeutic agent for ALL with t(4;11) and studies suggest that the antineoplastic effects are associated with reduced MLL-AF4 fusion protein and reduced expression of HOX genes. Here, we evaluated the in vitro effects of the combination of LBH589 with methotrexate (MTX) or 6-mercaptopurine (6MP) by cell proliferation assays and Calcusyn software in ALL cell line (RS4;11); the in vivo effects of LBH589 in xenotransplanted NOD-scid IL2Rgammanull mice measuring human lymphoblasts by flow cytometry; and the expression of HOX genes by qPCR after treatment in an adult model of ALL with t(4;11). LBH589 combination with MTX or 6MP did not promote synergistic effects in RS4;11 cell line. LBH589 treatment leads to increased overall survival and reduction of blasts in xenotransplanted mice but caused no significant changes in HOXA7, HOXA9, HOXA10, and MEIS1 expression. The LBH589, alone, showed promising antineoplastic effects in vivo and may represent a potential agent for chemotherapy in ALL patients with t(4;11). [ABSTRACT FROM AUTHOR]

6-Mercaptopurine (6-MP) is a well-known immunosuppressive medication with proven anti-proliferative activities. 6-MP possesses incomplete and highly variable oral absorption due to its poor water solubility, which might reduce its anti-cancer properties. To overcome these negative effects, we developed neutral and positively charged drug-loaded liposomal formulations utilizing the thin-film hydration technique. The prepared liposomal formulations were characterized for their size, polydispersity index (PDI), zeta potential, and entrapment efficiency. The average size of the prepared liposomes was between 574.67 ± 37.29 and 660.47 ± 44.32 nm. Positively charged liposomes (F1 and F3) exhibited a lower PDI than the corresponding neutrally charged ones (F2 and F4). Entrapment efficiency was higher in the neutral liposomes when compared to the charged formulation. F1 showed the lowest IC50 against HepG2, HCT116, and MCF-7 cancer cells. HepG2 cells treated with F1 showed the highest level of inhibition of cell proliferation with no evidence of apoptosis. Cell cycle analysis showed an increase in the G1/G0 and S phases, along with a decrease in the G2/M phases in the cell lines treated with drug loaded positively charged liposomes when compared to free positive liposomes, indicating arrest of cells in the S phase due to the stoppage of priming and DNA synthesis outside the mitotic phase. As a result, liposomes could be considered as an effective drug delivery system for treatment of a variety of cancers; they provide a chance that a nanoformulation of 6-MP will boost the cytotoxicity of the drug in a small pharmacological dose which provides a dosage advantage. [ABSTRACT FROM AUTHOR]

Background: As a promising strategy to overcome the therapeutic disadvantages of 6-mercaptopurine (6MP), we proposed the encapsulation of 6MP in chitosan nanoparticles (CNPs) to form the 6MP-CNPs complexes. The encapsulation was followed by the loading of complexes on gold nanoparticles (AuNPs) to generate a novel 6MP-CNPs-AuNPs nanocomposite to facilitate the chemo-photothermal therapeutic effect. Methods: CNPs were produced based on the ionic gelation method of tripolyphosphate (TPP). Moreover, 6MP-CNPs composite were prepared by the modified ionic gelation method and then loaded on AuNPs which were synthesized according to the standard wet chemical method using trisodium citrate as a reducing and capping agent. The synthesized nanocomposites were characterized by UV–VIS spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The potential cytotoxicity of the prepared nanocomposites on MCF7 cell line was carried out using Sulphorhodamine-B (SRB) assay. Results: Optimization of CNPs, 6MP-CNPs, and 6MP-CNPs-AuNPs revealed 130 ± 10, 200 ± 20, and 25 ± 5 nm particle size diameters with narrow size distributions and exhibited high stability with zeta potential 36.9 ± 4.11, 37, and 44.4 mV, respectively. The encapsulation efficiency of 6MP was found to be 57%. The cytotoxicity of 6MP-CNPs and 6MP-CNPs-AuNPs on breast cell line MCF7 was significantly increased and reached IC50 of 9.3 and 8.7 µM, respectively. The co-therapeutic effect of the nanocomposites resulted in an improvement of the therapeutic efficacy compared to the individual effect of chemo- and photothermal therapy. Irradiation of 6MP-CNPs and 6MP-CNPs-AuNPs with a diode laser (DPSS laser, 532 nm) was found to have more inhibition on cell viability with a decrease in IC50 to 5 and 4.4 µM, respectively. Conclusion: The Chemo-Photothermal co-therapy treatment with novel prepared nanocomposite exhibits maximum therapeutic efficacy and limits the dosage-related side effects of 6MP. [ABSTRACT FROM AUTHOR]

Complement-mediated hemolytic uremic syndrome (CM-HUS) following chemotherapy for pediatric acute lymphoid neoplasms has rarely been reported. We report the case of an 8-year-old boy with T-lymphoblastic lymphoma (T-LBL) who developed CM-HUS with complement factor H (CFH) mutations (S1191L, V1197A) during induction therapy. Safe administration of chemotherapy after CM-HUS recovery was challenging. By closely monitoring hemolytic and renal parameters during the 2-year treatment period, we observed four episodes of microangiopathic hemolytic anemia (MAHA) with hypocomplementemia and low haptoglobin but no renal dysfunction or thrombocytopenia. Here, we describe the MAHA and CM-HUS episodes in the hopes of elucidating the complex pathophysiology of disorders associated with CFH mutation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A robust nanozyme β-CD@MnO 2 NNS was designed via simple modification. • β-CD@MnO 2 NNS possesses excellently enhanced catalytic activity. • Visual and portable smartphone-integrated sensing of 6-mercaptopurine was realized. • The proposed method has a wide linear range and a low LOD. • This method displays a good assay performance in real samples. 6-mercaptopurine (6-MP) is widely used in the treatment of many diseases, but exhibits some serious side effects due to its toxicity. Therefore, it is important and imperative to effectively control and monitoring concentration of 6-MP. Herein, we designed a smartphone-assisted colorimetric sensing platform for 6-MP detection, based on an excellent β-cyclodextrin modified MnO 2 nanosheets (β-CD@MnO 2 NNS) mediated oxidase-like activity. β-CD@MnO 2 NNS can directly oxidizes 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized TMB with color changes, yielding more than 3-fold higher oxidase-like catalytic activity compared with individual MnO 2 NNS. After adding 6-MP, β-CD@MnO 2 NNS can be reduced to Mn2+ and lose their oxidase-like properties, resulting in a color and absorbance change for sensitive and selectivity detection of 6-MP. Meanwhile, the smartphone-based color recognition application can intuitively and simply measure the concentration of 6-MP. The limits of detection UV–vis instrument and smartphone were 0.35 μM and 0.86 μM, respectively. This method has also been successfully applied to the detection of real samples. Finally, this study provides a new promising platform for detection of 6-MP and is expected to be used in application of pharmaceutical analysis and biomedicine. [ABSTRACT FROM AUTHOR]

Autoimmune enteropathy (AIE) is a rare disease, characterized by intractable diarrhea, villous atrophy of the small intestine, and the presence of circulating anti-enterocyte autoantibodies. Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, and mutations in FOXP3, which is a master gene of regulatory T cells (Tregs), are major causes of AIE. Recent studies have demonstrated that mutations in other Treg-associated genes, such as CD25 and CTLA4, show an IPEX-like phenotype. We present the case of a 13-year-old girl with CTLA4 haploinsufficiency, suffering from recurrent immune thrombocytopenic purpura and intractable diarrhea. We detected an autoantibody to the AIE-related 75 kDa antigen (AIE-75), a hallmark of the IPEX syndrome, in her serum. She responded well to a medium dose of prednisolone and a controlled dose of 6-mercaptopurine (6-MP), even after the cessation of prednisolone administration. Serum levels of the soluble interleukin-2 receptor and immunoglobulin G (IgG) were useful in monitoring disease activity during 6-MP therapy. In conclusion, autoimmune-mediated mechanisms, similar to the IPEX syndrome, may be involved in the development of enteropathy in CTLA4 haploinsufficiency. Treatment with 6-MP and monitoring of disease activity using serum levels of soluble interleukin-2 receptor and IgG is suggested for such cases.

Introduction: Mercaptopurine (6-MP) is the backbone of the consolidation and maintenance therapy for paediatric acute lymphoblastic leukaemia (ALL). Nevertheless, it can cause critical myelosuppression. Predicting adverse reactions to 6-MP often involves the investigation of pharmacogenetic variants; in particular thiopurine S-methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15). Lately, NUDT15 variants have been shown to play a significant pharmacogenetic role in predicting 6-MP intolerance in children of Asian descent. Case Report: We present a six-year-old male child of Indian origin with persistent cytopenia after treatment. This prompted targeted sequencing of the genes TPMT and NUD15. The results revealed two copies of the variant of NUD15 rs116855232, that is, NUDT15 *2 genotype. Management and Outcome: Since the NUDT15 *2 allele classified the patient as a poor metabolizer, he was restarted on a low dose of 6-MP, which he tolerated. Discussion: Individuals with the NUDT15 *2allele (*2/*2 genotype) are poor metabolizers of thiopurines which results in an adverse reaction to 6-MP. About 3.5% of Indians show variations in the TPMT gene as compared to 19.4% variations observed in NUDT15, which makes the latter a more reliable disease marker. [ABSTRACT FROM AUTHOR]

Summary: Inherited genetic variation is associated with 6‐mercaptopurine (6‐MP) dose reduction and frequent toxicities induced by 6‐MP. However, the tolerable dose for 6‐MP is not fully predicted by the known variation in NUDT15 and TPMT among Asian children with acute lymphoblastic leukaemia (ALL). We performed a genome‐wide association study (GWAS) related to 6‐MP dose among Japanese children with ALL. This GWAS comprised 224 patients previously enrolled in Tokyo Children's Cancer Study Group clinical studies with replication attempted in 55 patients. Genome‐wide single nucleotide polymorphism (SNP) genotypes were evaluated for association with average 6‐MP dose during the initial 168 days of maintenance therapy. Possible associations were observed across five gene‐coding regions, among which only variants at 13q14.2 were significant and replicated genome‐wide (rs116855232, NUDT15, β = −10.99, p = 3.7 × 10−13). Notable findings were observed for variants in AFF3 (rs75364948, p = 2.05 × 10−6) and CHST11 (rs1148407, p = 2.09 × 10−6), but were not replicated possibly due to small numbers. A previously reported candidate SNP in MTHFR was associated with higher average 6‐MP dose (rs1801133, p = 0.045), and FOLH1 (rs12574928) was associated in an evaluation of candidate regions (padjust = 0.013). This study provides strong evidence that rs116855232 in NUDT15 is the genetic factor predominantly associated with 6‐MP tolerable dose in children in Japan. [ABSTRACT FROM AUTHOR]

Summary: 6‐Mercaptopurine (6‐MP) is widely used for the treatment of paediatric leukaemia and lymphoma. Recently, germline variants in the NUDT15 gene have been identified as one of the major genetic causes for 6‐MP–associated adverse effects such as myelosuppression. Patients with hypomorphic NUDT15 variants accumulate excessive levels of DNA‐incorporated thioguanine in white blood cells, resulting in severe myelosuppression. Although preclinical studies suggest that these variants may influence the protein stability of NUDT15, this has not been directly characterised in patients. In this study, we report the development of a series of novel monoclonal antibodies against NUDT15, using which we quantitatively assessed NUDT15 protein levels in 37 patients with acute lymphoblastic leukaemia treated with 6‐MP, using sandwich enzyme‐linked immunosorbent assay (ELISA). The NUDT15 genotype was highly correlated with its protein levels (p < 0.0001), with homozygous and compound heterozygous patients showing exceedingly low NUDT15 expression. There was a positive correlation between NUDT15 protein level and 6‐MP tolerance (r = 0.631, p < 0.0001). In conclusion, our results point to low NUDT15 protein abundance as the biochemical basis for NUDT15‐mediated 6‐MP intolerance, thus providing a phenotypic readout of inherited NUDT15 deficiency. [ABSTRACT FROM AUTHOR]

Thiopurine drugs azathioprine (AZA) and 6-mercaptopurine (6-MP) are used extensively in pediatric and adult patients with inflammatory and neoplastic diseases. They are metabolized to 6-thioguanine nucleotides (6-TGN) or to 6-methyl-mercaptopurine nucleotides (6-MMPN). The balance between 6-TGN and 6-MMPN is highly variable and monitoring is recommended, but its benefit in outcome gives rise to conflicting results, potentially increased by differences in quantifying 6-MP metabolism. Our aim was to report (1) the HPLC-UV procedure used in our laboratory to quantify red blood cells (RBCs) with 6-TGN and 6-MMPN (as its derivate: 6-MMP(d)) in patients treated with thiopurines and (2) additional tests, sometimes confirmatory, to improve method standardization. The comparison of two methods to count RBCs shows that metabolite concentrations were slightly lower in the washed and resuspended RBCs than in whole blood. Perchloric acid (0.7 M), dithiothreitol (DTT, final 0.013 M sample concentration) and 60 min hydrolysis were selected for acid hydrolysis. (3) Monitoring data from 83 patients receiving AZA or 6-MP showed that at steady state, only 53/183 (29%) had 6-TGN and 6-MMPN in the recommended therapeutic range. Our method is discussed in light of the technical conditions and sample stability data from 17 publications identified since the first analytical report in 1987. Monitoring data demonstrate, if required, that inter-patient variability in 6-TGN and 6-MMPN concentrations is high in samples from treated patients. [ABSTRACT FROM AUTHOR]

6-mercaptopurine (6-MP) plays a critical role in the treatment of pediatric acute lymphoblastic leukemia (ALL). NUDT15 and TPMT gene variants have been strongly associated with myelotoxicity caused by using 6-MP. Therefore, the purpose of this study is to investigate the frequency of NUDT15 and TPMT polymorphisms, as well as the impact of NUDT15 variants on the use of 6-MP to treat pediatric ALL in Vietnam. Sanger sequencing was applied to detect NUDT15 and TPMT gene variants in 70 pediatric ALL patients. Duration of drug interruption, level of neutropenia, and 6-MP tolerance dose were recorded. NUDT15 variants were detected from 23 out of 70 (32.9%) patients. Three well-known haplotype variants were identified as NUDT15 *2 (p.V18_V19insGV and p.R139C), *3 (p.R139C), and *6 (p.V18_V19insGV); besides, a novel NUDT15 p.R11Q was not previously reported. The NUDT15 wild-type, heterozygous variant, and homozygous variant genotypes were 67.1%, 30.1%, and 2.8%, respectively. Two TPMT heterozygous polymorphisms were TPMT*3C and *6, accounted for 2.8%. Patients with intermediate and low activity NUDT15 were given the median 6-MP tolerance dose of 55.2 and 37.2 versus 69.5 mg/m2/day of patients with NUDT15 normal activity (p = 0.0001). Patients with homozygous variant diplotype were drastically sensitive to 6-MP, with an average dose intensity of 49.6%, compared to 73.6% and 92.7% of those with heterozygous and wild-type diplotype, respectively (p = 0.0001). Our results suggest that 6-MP dose adjustment should be based on NUDT15 variants in pediatric Vietnamese ALL patients. [ABSTRACT FROM AUTHOR]

Objective To compare oral 6-mercaptopurine（6-MP）tolerance during maintenance therapy between children with wild-type and mutant acute lymphoblastic leukemia（ALL）at rs116855232 of NUDT15 gene. Methods Thirty-two children with ALL were divided into the wild-type group（24 cases）and mutant group（8 cases）according to the presence or absence of mutation at rs116855232 of NUDT15 gene. The doses of 6-MP，blood count，frequency of agranulocytosis during maintenance treatment，frequency of usage of short-acting recombinant human granulocyte colony-stimulating factor，frequency of infection，level of liver function，and prognosis of children were compared between the two groups. Results Compared with the wild-type group，the daily dosage of 6-MP in the mutant group was less（P<0. 05）. Compared with the wild-type group，the levels of leukocytes and platelets in the mutant group decreased（both P<0. 05）. Compared with the wild-type group，the frequencies of agranulocytosis and usage of short-acting recombinant human granulocyte colony-stimulating factor in the mutant group increased（both P<0. 05）. No significant difference was found in the infection frequency between the two groups（P>0. 05）. Compared with the wild-type group，the levels of ALT and AFU in the mutant group decreased（both P<0. 05）. The primary disease of children in the two groups was in complete remission. Conclusions Compared with the wild-type，the rs116855232 mutation in the NUDT15 gene reduces mercaptopurine tol⁃ erance in children with ALL，reduces the dosage of 6-MP，decreases white blood cells and platelets，and increases the risk of myelosuppression，but does not increase the risk of infection. The risk of abnormal liver function decreases，and the primary disease control is not affected. [ABSTRACT FROM AUTHOR]

Thiopurine prodrugs (azathioprine, AZA, and 6-mercaptopurine, 6MP) are embryotoxic to rodents and rabbits. Little is known about the developmental toxicity of 6-methylmercaptopurine riboside (6MMPr), a thiopurine drug metabolite that is thought to mediate its liver toxicity. A limb bud assay found that 6MMPr impairs the in vitro morphogenetic differentiation of mouse limb extremities, being more potent than 6MP in the assay. This study evaluated the embryotoxicity of 6MMPr (0, 7.5, 15, 30 mg/kg bw sc) in rats after single-dose exposure in mid organogenesis (GD10). One group of pregnant rats was similarly treated with 6MP (15 mg/kg bw sc). After C-section (GD21), fetuses were weighed, and examined for external abnormalities. One third of each litter was examined for soft-tissue abnormalities while the remaining fetuses were cleared and stained for skeleton evaluation. 6MMPr caused a dose-dependent maternal weight loss followed by recovery before term pregnancy. Except for a nonsignificant increase in embryolethality and slight reduction in fetal weight at 30 mg/kg bw, no indication of embryotoxicity was noted at this dose or at lower doses of 6MMPr. In contrast, 6MP led to nearly 98 % of post-implantation losses in the presence of slight-to-mild maternal toxicity. These results are consistent with the notion that maternal treatment with 6MMPr affects embryo development, causing a nonsignificant increase in embryolethality and a slight reduction in fetal weight at 30 mg/kg bw. However, there was no increase in abnormalities at this dose, which was severely toxic to the dams, as reflected in the maternal weight gain data. • Repeated dosing with 6MMPr (≥7.5 mg/kg bw/d) was lethal to non-pregnant female rats. • Single doses of 6MMPr ≥ 7.5 mg/kg bw were maternally toxic. • Even at maternally toxic doses, 6MMPr caused no increase in fetal abnormalities in rats. • 6MMPr given in mid-organogenesis (GD10) was not teratogenic. • In contrast to 6MMPr, 6MP was a developmental toxicant in rats. [ABSTRACT FROM AUTHOR]