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Despite great therapeutic advances in the field of biologics, small synthetic molecules such as thiopurines, including azathioprine, mercaptopurine, and thioguanine, remain an important therapeutic pillar in the treatment of inflammatory bowel disease, other autoimmune disorders, and cancer. This review presents the latest guidelines for thiopurine administration, highlighting the importance of individualized therapy guided by pharmacogenomics. It emphasizes dose adjustment based on nudix hydrolase 15 (NUDT15) and thiopurine S-methyltransferase (TPMT) genotype, along side thiopurine S-methyltransferase activity and thiopurine metabolic profile. In addition, the article takes a critical look at emerging research in the field of thiopurine pharmaco genomics featuring novel genetic markers and technological developments in genetic testing. Finally, the potential of integrated approaches that combine genetic, meta bolic, and clinical factors to further individualize thiopurine therapy is highlighted.

Due to their impact on several oncogenic client proteins, the Hsp90 family of chaperones has been widely studied for the development of potential anticancer agents. Although several Hsp90 inhibitors have entered clinical trials, most were unsuccessful because they induced a heat shock response (HSR). This issue can be circumvented by using isoform-selective inhibitors, but the high similarity in the ATP-binding sites between the isoforms presents a challenge. Given that Hsp90 shares a conserved Bergerat fold with bacterial DNA gyrase B and human topoisomerase IIα, we repurposed our ATP-competitive inhibitors of these two proteins for Hsp90 inhibition. We virtually screened a library of in-house inhibitors and identified eleven hits for evaluation of Hsp90 binding. Among these, compound 11 displayed low micromolar affinity for Hsp90 and demonstrated a 12-fold selectivity for Hsp90β over its closest isoform, Hsp90α. Out of 29 prepared analogs, 16 showed a preference for Hsp90β over Hsp90α. Furthermore, eleven of these compounds inhibited the growth of several cancer cell lines in vitro. Notably, compound 24e reduced intracellular levels of Hsp90 client proteins in MCF-7 cells, leading to cell cycle arrest in the G0/G1 phase without inducing HSR. This inhibitor exhibited at least a 27-fold preference for Hsp90β and was selective against topoisomerase IIα, a panel of 22 representative protein kinases, and proved to be non-toxic in a zebrafish larvae toxicology model. Finally, molecular modeling, corroborated by STD NMR studies, and the binding of 24e to the S52A mutant of Hsp90α confirmed that the serine to alanine switch drives the selectivity between the two cytoplasmic isoforms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Heat shock protein 90 (Hsp90) and topoisomerase IIα (TopoIIα) are members of the GHKL protein superfamily, both with clinically validated roles as anticancer drug targets. We report the discovery of the first class of dual inhibitors targeting the ATP-binding site of TopoIIα and the C-terminal domain of Hsp90, displaying potent cancer growth inhibition both in vitro and in vivo. Initially, a known TopoIIα inhibitor, compound 3, was shown to bind to the C-terminal domain of Hsp90, but not to its ATP-binding N-terminal domain. Nineteen analogs were then prepared and evaluated to investigate the structure-activity relationships, several of which inhibited the growth of SK-N-MC Ewing sarcoma cells in vitro. Compound 3 emerged as one of the most potent growth inhibitors (IC 50  = 0.33 ± 0.04 µM), demonstrating the ability to induce apoptosis and cell cycle arrest in SK-N-MC cells in vitro, and to slow the growth of Ewing sarcoma in vivo in a zebrafish model., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The interaction between heat shock protein 90 (Hsp90) and Hsp90 co-chaperone cell-division cycle 37 (Cdc37) is crucial for the folding and maturation of several oncogenic proteins, particularly protein kinases. This makes the inhibition of this protein-protein interaction (PPI) an interesting target for developing new anticancer compounds. However, due to the large interaction surface, developing PPI inhibitors is challenging. In this work, we describe the discovery of new Hsp90-Cdc37 PPI inhibitors using a ligand-based virtual screening approach. Initial hit compounds showed Hsp90 binding, resulting in anticancer activity in the MCF-7 breast cancer cell line. To optimize their antiproliferative effect, 35 analogs were prepared. Binding affinity for Hsp90 was determined for the most promising compounds, 8c ( K d = 70.8 μM) and 13g ( K d = 73.3 μM), both of which interfered with the binding of Cdc37 to Hsp90. This resulted in anticancer activity against Ewing sarcoma (SK-N-MC), breast cancer (MCF-7), and leukemia (THP-1) cell lines in vitro . Furthermore, compounds 8c and 13g demonstrated the ability to induce apoptosis in the Ewing sarcoma cell line and caused a decrease in the levels of several known Hsp90 client proteins in MCF-7 cells, all without inducing the heat shock response., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

Plasma membranes are vital biological structures, serving as protective barriers and participating in various cellular processes. In the field of super-resolution optical microscopy, stimulated emission depletion (STED) nanoscopy has emerged as a powerful method for investigating plasma membrane-related phenomena. However, many applications of STED microscopy are critically restricted by the limited availability of suitable fluorescent probes. This paper reports on the development of two amphiphilic membrane probes, SHE-2H and SHE-2N, specially designed for STED nanoscopy. SHE-2N, in particular, demonstrates quick and stable plasma membrane labelling with negligible intracellular redistribution. Both probes exhibit outstanding photostability and resolution improvement in STED nanoscopy, and are also suited for two-photon excitation microscopy. Furthermore, microscopy experiments and cytotoxicity tests revealed no noticeable cytotoxicity of probe SHE-2N at concentration used for fluorescence imaging. Spectral analysis and fluorescence lifetime measurements conducted on probe SHE-2N using giant unilamellar vesicles, revealed that emission spectra and fluorescence lifetimes exhibited minimal sensitivity to lipid composition variations. These novel probes significantly augment the arsenal of tools available for high-resolution plasma membrane research, enabling a more profound exploration of cellular processes and dynamics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

The development of new anticancer agents is one of the most urgent topics in drug discovery. Inhibition of molecular chaperone Hsp90 stands out as an approach that affects various oncogenic proteins in different types of cancer. These proteins rely on Hsp90 to obtain their functional structure, and thus Hsp90 is indirectly involved in the pathophysiology of cancer. However, the most studied ATP-competitive inhibition of Hsp90 at the N-terminal domain has proven to be largely unsuccessful clinically. Therefore, research has shifted towards Hsp90 C-terminal domain (CTD) inhibitors, which are also the focus of this study. Our recent discovery of compound C has provided us with a starting point for exploring the structure-activity relationship and optimising this new class of triazole-based Hsp90 inhibitors. This investigation has ultimately led to a library of 33 analogues of C that have suitable physicochemical properties and several inhibit the growth of different cancer types in the low micromolar range. Inhibition of Hsp90 was confirmed by biophysical and cellular assays and the binding epitopes of selected inhibitors were studied by STD NMR. Furthermore, the most promising Hsp90 CTD inhibitor 5x was shown to induce apoptosis in breast cancer (MCF-7) and Ewing sarcoma (SK-N-MC) cells while inducing cause cell cycle arrest in MCF-7 cells. In MCF-7 cells, it caused a decrease in the levels of ERα and IGF1R, known Hsp90 client proteins. Finally, 5x was tested in zebrafish larvae xenografted with SK-N-MC tumour cells, where it limited tumour growth with no obvious adverse effects on normal zebrafish development., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Advances in research, including novel biomarker identification and patient stratification, have significantly improved the therapy for childhood acute lymphoblastic leukemia (ALL), though access to improved healthcare services varies across geographical regions. In an effort to evaluate the advances in therapeutic approaches, we performed a retrospective analysis of childhood ALL in Kosovo. Our retrospective analysis included 225 cases diagnosed between 2008 and 2023, representing 52% of 429 diagnosed childhood cancers. The average annual incidence was 14, with a median age diagnosis of seven years, and a male predominance (59.54%). Patients were categorized into risk groups, with the majority (43%) in the standard-risk category. We identified five different treatment protocols for this study period. Over 61% of patients achieved remission after the first chemotherapy cycle and we observed a 20% mortality rate. Survival analysis showed that 55% and 40% of patients achieved 2-year and 5-year event-free survival (EFS), respectively, with significant differences across risk groups. Treatment advancements significantly correlated with improved survival rates, achieving a 5-year overall survival (OS) of 88% in the currently used standardized AIEOP-BFM-2009 protocol. Our study emphasizes the need for continued research and customized care strategies to enhance clinical outcomes.

Determining variant TPMT alleles to predict patient response to thiopurine therapy represents one of the first successful implementations of pharmacogenomics in clinical practice. However, despite the TPMT -adjusted thiopurine dosing, some TPMT wild-type patients still exhibit toxicity at standard doses. Over the past decade, the pharmacogene NUDT15 has emerged as a significant co-modulator of thiopurine therapy. Initially, NUDT15 was considered important predominantly in Asian populations, but recent studies have highlighted its relevance in European populations as well.To evaluate the pharmacogenetic significance of NUDT15 in the Slovenian population, we sequenced extended regions of exon 1 and exon 3 in 109 healthy individuals and 37 patients with acute lymphoblastic leukemia.We identified eight variants, including one with established clinical significance (allele *3) and one extremely rare variant (Chr13 at 48045861; GRCh38, NC_000013.11). The frequencies of most previously described variants in both the general population and in the ALL cohort were consistent with those reported in other European populations, except for rs45465203, which was less frequent in the Slovenian population. None of the variants, except for NUDT15*3 , were associated with cumulative thiopurine doses in ALL patients. However, these variants warrant further investigation in larger ALL cohorts.

Thiopurine S-methyltransferase (TPMT) is an important enzyme involved in the deactivation of thiopurines and represents a major determinant of thiopurine-related toxicities. Despite its well-known importance in thiopurine metabolism, the understanding of its endogenous role is lacking. In the present study, we aimed to gain insight into the molecular processes involving TPMT by applying a data fusion approach to analyze whole-genome expression data. The RNA profiling was done on whole blood samples from 1017 adult male and female donors to the Estonian biobank using Illumina HTv3 arrays. Our results suggest that TPMT is closely related to genes involved in oxidoreductive processes. The in vitro experiments on different cell models confirmed that TPMT influences redox capacity of the cell by altering S-adenosylmethionine (SAM) consumption and consequently glutathione (GSH) synthesis. Furthermore, by comparing gene networks of subgroups of individuals, we identified genes, which could have a role in regulating TPMT activity. The biological relevance of identified genes and pathways will have to be further evaluated in molecular studies., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest that are directly relevant to the content of this article., (Copyright © 2023. Published by Elsevier B.V.)

Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sensitivity when compared to NSBs analyzed with a clinical RT-qPCR test. The diagnostic sensitivity for passive drool saliva was higher than that of oral cavity swab specimens (95% and 87%, respectively). A rapid, sensitive one-step extraction-free RT-qPCR test for detecting SARS-CoV-2 in passive drool saliva is operationally simple and can be easily implemented using existing testing sites, thus allowing high-throughput, rapid, and repeated testing of large populations. Furthermore, saliva testing is adequate to detect individuals in an asymptomatic screening program and can help improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

NOD1 and NOD2 are pattern recognition receptors that have important roles in innate immune responses. Although their overactivation has been linked to a number of diseases, NOD2 in particular remains a virtually unexploited target in this respect, with only one structural class of antagonist reported. To gain insight into the structure-activity relationships of NOD2 antagonists, a series of novel analogs was designed and synthesized, and then screened for antagonist activity versus NOD2, and counter-screened versus NOD1. Compounds 32 and 38 were identified as potent and moderately selective NOD2 antagonists, and 33 and 42 as dual NOD1/NOD2 antagonists, with balanced activities against both targets in the low micromolar range. These data enable in-depth exploration of their structure-activity relationships and provide deeper understanding of the structural features required for NOD2 antagonism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Background: Methylation driven by thiopurine S-methylatransferase (TPMT) is crucial for deactivation of cytostatic and immunosuppressant thiopurines. Despite its remarkable integration into clinical practice, the endogenous function of TPMT is unknown., Methods: To address the role of TPMT in methylation of selenium compounds, we established the research on saturation transfer difference (STD) and 77 Se NMR spectroscopy, fluorescence measurements, as well as computational molecular docking simulations., Results: Using STD NMR spectroscopy and fluorescence measurements of tryptophan residues in TPMT, we determined the binding of selenocysteine (Sec) to human recombinant TPMT. By comparing binding characteristics of Sec in the absence and in the presence of methyl donor, we confirmed S-adenosylmethionine (SAM)-induced conformational changes in TPMT. Molecular docking analysis positioned Sec into the active site of TPMT with orientation relevant for methylation reaction. Se-methylselenocysteine (MeSec), produced in the enzymatic reaction, was detected by 77 Se NMR spectroscopy. A direct interaction between Sec and SAM in the active site of rTPMT and the formation of both products, MeSec and S-adenosylhomocysteine, was demonstrated using NMR spectroscopy., Conclusions: The present study provides evidence on in vitro methylation of Sec by rTPMT in a SAM-dependant manner., General Significance: Our results suggest novel role of TPMT and demonstrate new insights into enzymatic modifications of the 21st amino acid., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Aim: SNPs in the gene for TPMT exemplify one of the most successful translations of pharmacogenomics into clinical practice. This study explains the correlation between common SNPs and variable number of tandem repeats (VNTR) in promoter of the gene., Materials & Methods: We determined VNTR polymorphisms, as well as TPMT*2 and TPMT*3 SNPs and TPMT activity in Slovenian and Italian individuals and lymphoblastoid cell lines., Results: We observed a previously unreported VNTR allele, AB7C, in a TPMT*3A heterozygous individual. VNTRs with two (AB2C) and three or more (ABnC, n ≥ 3) B motifs were statistically significant in complete linkage disequilibrium (D' = 1, r 2  = 1, p < 0.0001) with the TPMT*3C and TPMT*3A alleles, respectively., Conclusion: The study provides insights into the stepwise evolution of TPMT*3 alleles from *3C to *3A, with increasing number of B motifs in the VNTR region.

NOD1 and NOD2 are important members of the pattern recognition receptor family and play a crucial role within the context of innate immunity. However, overactivation of NODs, especially of NOD1, has also been implicated in a number of diseases. Surprisingly, NOD1 remains a virtually unexploited target in this respect. To gain additional insight into the structure-activity relationships of NOD1 inhibitors, a series of novel analogs has been designed and synthesized and then screened for their NOD1-inhibitory activity. Selected compounds were also investigated for their NOD2-inhibitory activity. Two compounds 4 and 15, were identified as potent mixed inhibitors of NOD1 and NOD2, displaying a balanced inhibitory activity on both targets in the low micromolar range. The results obtained have enabled a deeper understanding of the structural requirements for NOD1 and NOD2 inhibition., (Copyright © 2016 Elsevier Ltd. All rights reserved.)