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Redox Biology Nov 2023NRF2 is a master transcription factor that regulates the stress response. NRF2 is frequently mutated and activated in human esophageal squamous cell carcinoma (ESCC),...
OBJECTIVE
NRF2 is a master transcription factor that regulates the stress response. NRF2 is frequently mutated and activated in human esophageal squamous cell carcinoma (ESCC), which drives resistance to chemotherapy and radiation therapy. Therefore, a great need exists for NRF2 inhibitors for targeted therapy of NRF2 ESCC.
DESIGN
We performed high-throughput screening of two compound libraries from which hit compounds were further validated in human ESCC cells and a genetically modified mouse model. The mechanism of action of one compound was explored by biochemical assays.
RESULTS
Using high-throughput screening of two small molecule compound libraries, we identified 11 hit compounds as potential NRF2 inhibitors with minimal cytotoxicity at specified concentrations. We then validated two of these compounds, pyrimethamine and mitoxantrone, by demonstrating their dose- and time-dependent inhibitory effects on the expression of NRF2 and its target genes in two NRF2 human ESCC cells (KYSE70 and KYSE180). RNAseq and qPCR confirmed the suppression of global NRF2 signaling by these two compounds. Mechanistically, pyrimethamine reduced NRF2 half-life by promoting NRF2 ubiquitination and degradation in KYSE70 and KYSE180 cells. Expression of an Nrf2 allele in mouse esophageal epithelium (Sox2CreER;LSL-Nrf2) resulted in an NRF2 phenotype, which included squamous hyperplasia, hyperkeratinization, and hyperactive glycolysis. Treatment with pyrimethamine (30 mg/kg/day, p.o.) suppressed the NRF2 esophageal phenotype with no observed toxicity.
CONCLUSION
We have identified and validated pyrimethamine as an NRF2 inhibitor that may be rapidly tested in the clinic for NRF2 ESCC.
Topics: Humans; Animals; Mice; Esophageal Squamous Cell Carcinoma; Esophageal Neoplasms; NF-E2-Related Factor 2; Pyrimethamine; Hyperplasia; Cell Line, Tumor; Cell Proliferation
PubMed: 37776708
DOI: 10.1016/j.redox.2023.102901 -
Journal of Clinical Medicine Jan 2022Malaria is a prevalent parasitic disease that is estimated to kill between one and two million people-mostly children-every year. Here, we query PubMed for malaria drug...
Malaria is a prevalent parasitic disease that is estimated to kill between one and two million people-mostly children-every year. Here, we query PubMed for malaria drug resistance and plot the yearly citations of 14 common antimalarials. Remarkably, most antimalarial drugs display cyclic resistance patterns, rising and falling over four decades. The antimalarial drugs that exhibit cyclic resistance are quinine, chloroquine, mefloquine, amodiaquine, artesunate, artemether, sulfadoxine, doxycycline, halofantrine, piperaquine, pyrimethamine, atovaquone, artemisinin, and dihydroartemisinin. Exceptionally, the resistance of the two latter drugs can also correlate with a linear rise. Our predicted antimalarial drug resistance is consistent with clinical data reported by the Worldwide Antimalarial Resistance Network (WWARN) and validates our methodology. Notably, the cyclical resistance suggests that most antimalarial drugs are sustainable in the end. Furthermore, cyclic resistance is clinically relevant and discourages routine monotherapy, in particular, while resistance is on the rise. Finally, cyclic resistance encourages the combination of antimalarial drugs at distinct phases of resistance.
PubMed: 35160232
DOI: 10.3390/jcm11030781 -
Genome Medicine Nov 2023Malaria continues to be a major threat to global public health. Whole genome sequencing (WGS) of the underlying Plasmodium parasites has provided insights into the...
BACKGROUND
Malaria continues to be a major threat to global public health. Whole genome sequencing (WGS) of the underlying Plasmodium parasites has provided insights into the genomic epidemiology of malaria. Genome sequencing is rapidly gaining traction as a diagnostic and surveillance tool for clinical settings, where the profiling of co-infections, identification of imported malaria parasites, and detection of drug resistance are crucial for infection control and disease elimination. To support this informatically, we have developed the Malaria-Profiler tool, which rapidly (within minutes) predicts Plasmodium species, geographical source, and resistance to antimalarial drugs directly from WGS data.
RESULTS
The online and command line versions of Malaria-Profiler detect ~ 250 markers from genome sequences covering Plasmodium speciation, likely geographical source, and resistance to chloroquine, sulfadoxine-pyrimethamine (SP), and other anti-malarial drugs for P. falciparum, but also providing mutations for orthologous resistance genes in other species. The predictive performance of the mutation library was assessed using 9321 clinical isolates with WGS and geographical data, with most being single-species infections (P. falciparum 7152/7462, P. vivax 1502/1661, P. knowlesi 143/151, P. malariae 18/18, P. ovale ssp. 5/5), but co-infections were identified (456/9321; 4.8%). The accuracy of the predicted geographical profiles was high to both continental (96.1%) and regional levels (94.6%). For P. falciparum, markers were identified for resistance to chloroquine (49.2%; regional range: 24.5% to 100%), sulfadoxine (83.3%; 35.4- 90.5%), pyrimethamine (85.4%; 80.0-100%) and combined SP (77.4%). Markers associated with the partial resistance of artemisinin were found in WGS from isolates sourced from Southeast Asia (30.6%).
CONCLUSIONS
Malaria-Profiler is a user-friendly tool that can rapidly and accurately predict the geographical regional source and anti-malarial drug resistance profiles across large numbers of samples with WGS data. The software is flexible with modifiable bioinformatic pipelines. For example, it is possible to select the sequencing platform, display specific variants, and customise the format of outputs. With the increasing application of next-generation sequencing platforms on Plasmodium DNA, Malaria-Profiler has the potential to be integrated into point-of-care and surveillance settings, thereby assisting malaria control. Malaria-Profiler is available online (bioinformatics.lshtm.ac.uk/malaria-profiler) and as standalone software ( https://github.com/jodyphelan/malaria-profiler ).
Topics: Humans; Animals; Antimalarials; Parasites; Coinfection; Malaria; Plasmodium; Malaria, Falciparum; Chloroquine; Malaria, Vivax; Drug Resistance; Plasmodium falciparum
PubMed: 37950308
DOI: 10.1186/s13073-023-01247-7 -
International Journal For Parasitology Jun 2021The global spread of sulfadoxine (Sdx, S) and pyrimethamine (Pyr, P) resistance is attributed to increasing number of mutations in DHPS and DHFR enzymes encoded by... (Review)
Review
The global spread of sulfadoxine (Sdx, S) and pyrimethamine (Pyr, P) resistance is attributed to increasing number of mutations in DHPS and DHFR enzymes encoded by malaria parasites. The association between drug resistance mutations and SP efficacy is complex. Here we provide an overview of the geographical spread of SP resistance mutations in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) encoded dhps and dhfr genes. In addition, we have collated the mutation data and mapped it on to the three-dimensional structures of DHPS and DHFR which have become available. Data from genomic databases and 286 studies were collated to provide a comprehensive landscape of mutational data from 2005 to 2019. Our analyses show that the Pyr-resistant double mutations are widespread in Pf/PvDHFR (P. falciparum ∼61% in Asia and the Middle East, and in the Indian sub-continent; in P. vivax ∼33% globally) with triple mutations prevailing in Africa (∼66%) and South America (∼33%). For PfDHPS, triple mutations dominate South America (∼44%), Asia and the Middle East (∼34%) and the Indian sub-continent (∼27%), while single mutations are widespread in Africa (∼45%). Contrary to the status for P. falciparum, Sdx-resistant single point mutations in PvDHPS dominate globally. Alarmingly, highly resistant quintuple and sextuple mutations are rising in Africa (PfDHFR-DHPS) and Asia (Pf/PvDHFR-DHPS). Structural analyses of DHFR and DHPS proteins in complexes with substrates/drugs have revealed that resistance mutations map proximal to Sdx and Pyr binding sites. Thus new studies can focus on discovery of novel inhibitors that target the non-substrate binding grooves in these two validated malaria parasite drug targets.
Topics: Antimalarials; Dihydropteroate Synthase; Drug Combinations; Drug Resistance; Genotype; Mutation; Plasmodium falciparum; Pyrimethamine; Sulfadoxine; Tetrahydrofolate Dehydrogenase
PubMed: 33775670
DOI: 10.1016/j.ijpara.2020.12.011 -
Infection and Drug Resistance 2022The use of poor quality drugs will have multiple consequences with an extended hazard of growing drug-resistant strains. (Review)
Review
BACKGROUND
The use of poor quality drugs will have multiple consequences with an extended hazard of growing drug-resistant strains.
PURPOSE
The review aimed to provide the quality status of antimalarial drugs in East Africa.
DATA SOURCE
PubMed, Scopus, Web of Science, and Google Scholar were searched from September 5 to September 12, 2021.
STUDY SELECTION
The review included articles available as original research targeted at evaluating the quality of antimalarial drugs. For inclusion, data on at least one of the following quality control parameters were required: packaging and labeling, hardness, friability, weight variation/uniformity of weight, disintegration, dissolution, and assay/percentage purity. Mendeley citation manager version 1.19.4 was used to avoid duplication and organize references, and titles and abstracts were primarily used for screening.
DATA EXTRACTION
The sample collection site, drug name, and the quality control parameters tested were retrieved from the selected studies.
DATA SYNTHESIS
Totally, 300 antimalarial drug samples from Ethiopia, Kenya and Tanzania were included in this review. No antimalarial drug tested failed the identification and disintegration test. However, 15.93% (36/226), 5.00% (15/300), and 1.90% (3/158) of antimalarial samples failed the dissolution, assay and mass uniformity test, respectively. Moreover, amodiaquine and sulfadoxine/pyrimethamine samples failed dissolution and assay tests. In addition, amodiaquine samples failed the mass uniformity test. However, artemether/lumefantrine and quinine passed all quality control parameters tested. Overall, 19.67% (59/300) of antimalarial drug samples did not meet at least one quality control parameter. And the higher faller rate was reported for sulfadoxine/pyrimethamine accounting for 52.86% (37/70).
CONCLUSIONS
An unneglected amount of antimalarial drug failed to meet at least one quality control parameter. Strengthening pharmaceutical management systems, including post-marketing surveillance, and providing the resources required for medication quality assurance, are recommended.
PubMed: 36277242
DOI: 10.2147/IDR.S373059 -
Current Medicinal Chemistry Mar 2023Dihydrofolate reductase (DHFR) is an indispensable enzyme required for the survival of most prokaryotic and eukaryotic cells as it is involved in the biosynthesis of...
BACKGROUND
Dihydrofolate reductase (DHFR) is an indispensable enzyme required for the survival of most prokaryotic and eukaryotic cells as it is involved in the biosynthesis of essential cellular components. DHFR has attracted a lot of attention as a molecular target for various diseases like cancer, bacterial infection, malaria, tuberculosis, dental caries, trypanosomiasis, leishmaniasis, fungal infection, influenza, Buruli ulcer, and respiratory illness. Various teams of researchers have reported different DHFR inhibitors to explore their therapeutic efficacy. Despite all the progress made, there is a strong need to find more novel leading structures, which may be used as better and safe DHFR inhibitors, especially against the microorganisms which are resistant to the developed drug candidates.
OBJECTIVE
This review aims to pay attention to recent development, particularly made in the past two decades and published in this field, and pay particular attention to promising DHFR inhibitors. Hence, an attempt has been made in this article to highlight the structure of dihydrofolate reductase, the mechanism of action of DHFR inhibitors, most recently reported DHFR inhibitors, diverse pharmacological applications of DHFR inhibitors, reported in-silico study data and recent patents based on DHFR inhibitors to comprehensively portray the current scenery for researchers interested in designing novel DHFR inhibitors.
CONCLUSION
A critical review of recent studies revealed that most novel DHFR inhibitor compounds either synthetically or naturally derived are characterized by the presence of heterocyclic moieties in their structure. Non-classical antifolates like trimethoprim, pyrimethamine, and proguanil are considered excellent templates to design novel DHFR inhibitors, and most of them have substituted 2,4-diamino pyrimidine motifs. Targeting DHFR has massive potential to be investigated for newer therapeutic possibilities to treat various diseases of clinical importance.
PubMed: 36896902
DOI: 10.2174/0929867330666230310091510 -
Acta Bio-medica : Atenei Parmensis Jul 2023A two-month-old baby boy diagnosed with unspecific congenital toxoplasmosis was referred by a pediatrician to the Clinical Parasitology referral center at the Faculty of...
A two-month-old baby boy diagnosed with unspecific congenital toxoplasmosis was referred by a pediatrician to the Clinical Parasitology referral center at the Faculty of Medicine, Universitas Indonesia. Baby was post-hospitalized in the NICU and required ventilation support for one month. Furthermore, there was history of from various medical conditions, such as intracranial bleeding, convulsion, hypertrophic cardiomyopathy, retinopathy, and renal failure. After two month, there was no significant weight gain, anti-Toxoplasma IgM showed positive results, and anti-Toxoplasma IgM and IgG of the mother were also positive. Baby and mother were successfully treated with pyrimethamine, cotrimoxazole, and folinic acid for one month. At 2 years, there signs of normal motoric, eye, and hearing development with underdeveloped kidneys. Therefore, pre-pregnancy counseling and education aimed at preventing toxoplasmosis during pregnancy should be increased and conducted routinely by health workers or trained cadres to reduce the risk of fetal defects.
Topics: Infant; Pregnancy; Male; Female; Humans; Infant, Newborn; Toxoplasmosis, Congenital; Antibodies, Protozoan; Toxoplasma; Neonatal Screening; Immunoglobulin M
PubMed: 37486604
DOI: 10.23750/abm.v94iS1.14308 -
Journal of Basic Microbiology Dec 2022Malaria caused by Plasmodium vivax is comparatively less virulent than Plasmodium falciparum, which can also lead to severe disease and death. It shows a wide... (Review)
Review
Malaria caused by Plasmodium vivax is comparatively less virulent than Plasmodium falciparum, which can also lead to severe disease and death. It shows a wide geographical distribution. Chloroquine serves as a drug of choice, with primaquine as a radical cure. However, with the appearance of resistance to chloroquine and treatment has been shifted to artemisinin combination therapy followed by primaquine as a radical cure. Sulphadoxine-pyrimethamine, mefloquine, and atovaquone-proguanil are other drugs of choice in chloroquine-resistant areas, and later resistance was soon reported for these drugs also. The emergence of drug resistance serves as a major hurdle to controlling and eliminating malaria. The discovery of robust molecular markers and regular surveillance for the presence of mutations in malaria-endemic areas would serve as a helpful tool to combat drug resistance. Here, in this review, we will discuss the endemicity of P. vivax, a historical overview of antimalarial drugs, the appearance of drug resistance and molecular markers with their global distribution along with different measures taken to reduce malaria burden due to P. vivax infection and their resistance.
Topics: Humans; Plasmodium vivax; Primaquine; Antimalarials; Malaria, Vivax; Chloroquine; Malaria
PubMed: 36125207
DOI: 10.1002/jobm.202200316 -
IUBMB Life Mar 2022Cancer accounted for nearly 10 million deaths in 2020 and is the second leading cause of death worldwide. The chemotherapeutic agents that are in clinical practice... (Review)
Review
Cancer accounted for nearly 10 million deaths in 2020 and is the second leading cause of death worldwide. The chemotherapeutic agents that are in clinical practice possess a broad range of severe adverse effects towards vital organs which emphasizes the importance of the discovery of new therapeutic agents or repurposing of existing drugs for the treatment of human cancers. Pyrimethamine is an antiparasitic drug used for the treatment of malaria and toxoplasmosis with a well-documented excellent safety profile. In the last 5 years, numerous efforts have been made to explore the anticancer potential of pyrimethamine in in vitro and in vivo preclinical models and to repurpose it as an anticancer agent. The studies have demonstrated that pyrimethamine inhibits oncogenic proteins such as STAT3, NF-κB, DX2, MAPK, DHFR, thymidine phosphorylase, telomerase, and many more in a different types of cancer models. Moreover, pyrimethamine has been reported to work in synergy with other anticancer agents, such as temozolomide, to induce apoptosis of tumor cells. Recently, the results of phase-1/2 clinical trials demonstrated that pyrimethamine administration reduces the expression of STAT3 signature genes in tumor tissues of chronic lymphocytic leukemia patients with a good therapeutic response. In the present article, we have reviewed most of the published articles related to the antitumor effects of pyrimethamine in malignancies of breast, liver, lung, skin, ovary, prostate, pituitary, and leukemia in in vitro and in vivo settings. We have also discussed the pharmacokinetic profile and results of clinical trials obtained after pyrimethamine treatment. From these studies, we believe that pyrimethamine has the potential to be repurposed as an anticancer drug.
Topics: Antineoplastic Agents; Apoptosis; Female; Humans; Neoplasms; Pyrimethamine; Temozolomide
PubMed: 34921584
DOI: 10.1002/iub.2590 -
Molecules (Basel, Switzerland) Feb 2020In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand...
In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand the contribution of four point mutations (N51I, C59R, S108N, and I164L) within the active site of the malaria parasite enzyme dihydrofolate reductase (DHFR) towards the resistance of the antimalarial drug pyrimethamine. Homology modeling was used to obtain full-length models of wild type (WT) and mutant DHFR. Molecular docking was employed to dock pyrimethamine onto the generated structures. Subsequent all-atom molecular dynamics (MD) simulations and binding free-energy computations highlighted that pyrimethamine's stability and affinity inversely relates to the number of mutations within its binding site and, hence, resistance severity. Generally, mutations led to reduced binding affinity to pyrimethamine and increased conformational plasticity of DHFR. Next, dynamic residue network analysis (DRN) was applied to determine the impact of mutations and pyrimethamine binding on communication dispositions of DHFR residues. DRN revealed residues with distinctive communication profiles, distinguishing WT from drug-resistant mutants as well as pyrimethamine-bound from pyrimethamine-free models. Our results provide a new perspective on the understanding of mutation-induced drug resistance.
Topics: Amino Acids; Catalytic Domain; Drug Resistance; Ligands; Molecular Dynamics Simulation; Mutation; Plasmodium falciparum; Protein Domains; Pyrimethamine; Tetrahydrofolate Dehydrogenase; Thermodynamics
PubMed: 32085470
DOI: 10.3390/molecules25040904