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European Journal of Medicinal Chemistry Dec 2023The opportunistic apicomplexan parasite Toxoplasma gondii is the etiologic agent for toxoplasmosis, which can infect a widespread range of hosts, particularly humans and... (Review)
Review
The opportunistic apicomplexan parasite Toxoplasma gondii is the etiologic agent for toxoplasmosis, which can infect a widespread range of hosts, particularly humans and warm-blooded animals. The present chemotherapy to treat or prevent toxoplasmosis is deficient and is based on diverse drugs such as atovaquone, trimethoprim, spiramycine, which are effective in acute toxoplasmosis. Therefore, a safe chemotherapy is required for toxoplasmosis considering that its responsible agent, T. gondii, provokes severe illness and death in pregnant women and immunodeficient patients. A certain disadvantage of the available treatments is the lack of effectiveness against the tissue cyst of the parasite. A safe chemotherapy to combat toxoplasmosis should be based on the metabolic differences between the parasite and the mammalian host. This article covers different relevant molecular targets to combat this disease including the isoprenoid pathway (farnesyl diphosphate synthase, squalene synthase), dihydrofolate reductase, calcium-dependent protein kinases, histone deacetylase, mitochondrial electron transport chain, etc.
Topics: Animals; Humans; Female; Pregnancy; Toxoplasma; Toxoplasmosis; Atovaquone; Trimethoprim; Mammals
PubMed: 37871407
DOI: 10.1016/j.ejmech.2023.115885 -
Nature Communications Oct 2023Long-acting injectable medications, such as atovaquone, offer the prospect of a "chemical vaccine" for malaria, combining drug efficacy with vaccine durability. However,...
Long-acting injectable medications, such as atovaquone, offer the prospect of a "chemical vaccine" for malaria, combining drug efficacy with vaccine durability. However, selection and transmission of drug-resistant parasites is of concern. Laboratory studies have indicated that atovaquone resistance disadvantages parasites in mosquitoes, but lack of data on clinically relevant Plasmodium falciparum has hampered integration of these variable findings into drug development decisions. Here we generate atovaquone-resistant parasites that differ from wild type parent by only a Y268S mutation in cytochrome b, a modification associated with atovaquone treatment failure in humans. Relative to wild type, Y268S parasites evidence multiple defects, most marked in their development in mosquitoes, whether from Southeast Asia (Anopheles stephensi) or Africa (An. gambiae). Growth of asexual Y268S P. falciparum in human red cells is impaired, but parasite loss in the mosquito is progressive, from reduced gametocyte exflagellation, to smaller number and size of oocysts, and finally to absence of sporozoites. The Y268S mutant fails to transmit from mosquitoes to mice engrafted with human liver cells and erythrocytes. The severe-to-lethal fitness cost of clinically relevant atovaquone resistance to P. falciparum in the mosquito substantially lessens the likelihood of its transmission in the field.
Topics: Humans; Animals; Mice; Atovaquone; Parasites; Antimalarials; Malaria; Malaria, Falciparum; Plasmodium falciparum; Anopheles; Antiparasitic Agents; Vaccines
PubMed: 37828012
DOI: 10.1038/s41467-023-42030-x -
Materials Today. Bio Dec 2023Radiation therapy (RT) has emerged as one of the most promising anti-tumor strategies for neuroblastoma. Nevertheless, the special tumor microenvironment (TME),...
Radiation therapy (RT) has emerged as one of the most promising anti-tumor strategies for neuroblastoma. Nevertheless, the special tumor microenvironment (TME), including hypoxic and GSH-overexpressed TME, often greatly restricts the RT outcome. In this study, we demonstrated a dual-channel parallel radicals nanoamplifier (ATO@PAE-PEG-AS1411/Fe). The nanoamplifier was shaped into a bilayer shell-core structure, in which atovaquone-loaded poly (β-amino esters)-poly (ethylene glycol) (ATO@PAE-PEG) served as the core while Fe-absorbed AS1411 aptamer (AS1411/Fe) served as the shell. Taking advantage of the targeting ability of AS1411, ATO@PAE-PEG-AS1411/Fe specifically accumulated in tumor cells, and then released ATO as well as Fe in response to the acidic TME. The released ATO dramatically inhibited the mitochondrial respiration of tumor cells, thus sparing vast amounts of oxygen for the generation of free radicals during RT process, which was the first free radicals-amplifying pathway Meanwhile, the released Fe could consume the tumor-overexpressed GSH through the redox reaction, thus effectively preserving the generated free radicals in RT process, which was the second free radicals-amplifying pathway. Taken together, our study demonstrates a dual-channel parallel free radicals-amplifying RT strategy, and it is expected this work will promote the clinical application prospects of RT treatment against neuroblastoma.
PubMed: 37822451
DOI: 10.1016/j.mtbio.2023.100828 -
Pharmaceutical Patent Analyst Jul 2023Repurposing of approved drugs in a new strategy to combat cancer that leads to savings in time and investment. Atovaquone is a US FDA-approved drug for treatment of...
Repurposing of approved drugs in a new strategy to combat cancer that leads to savings in time and investment. Atovaquone is a US FDA-approved drug for treatment of pneumonia and malaria. Patent US2023017373 describe the use of mito-atovaquone for the treatment of several types of cancer. Mito-atovaquone demonstrated antiproliferative activity in cell lines of pancreatic cancer, lung cancer and brain cancer and inhibited tumor growth in syngeneic mouse models and in animals genetically prone to breast cancer. Mito-atovaquone has the potential to be used successfully in the treatment of various types of tumors.
Topics: Mice; Animals; Atovaquone; Drug Repositioning; Antifungal Agents; Naphthoquinones; Pneumonia, Pneumocystis; Neoplasms; Mitomycin
PubMed: 37801038
DOI: 10.4155/ppa-2023-0015 -
Frontiers in Pharmacology 2023
PubMed: 37767402
DOI: 10.3389/fphar.2023.1282233 -
Viruses Aug 2023The emergence of SARS-CoV-1 in 2003 followed by MERS-CoV and now SARS-CoV-2 has proven the latent threat these viruses pose to humanity. While the SARS-CoV-2 pandemic...
The emergence of SARS-CoV-1 in 2003 followed by MERS-CoV and now SARS-CoV-2 has proven the latent threat these viruses pose to humanity. While the SARS-CoV-2 pandemic has shifted to a stage of endemicity, the threat of new coronaviruses emerging from animal reservoirs remains. To address this issue, the global community must develop small molecule drugs targeting highly conserved structures in the coronavirus proteome. Here, we characterized existing drugs for their ability to inhibit the endoribonuclease activity of the SARS-CoV-2 non-structural protein 15 (nsp15) via in silico, in vitro, and in vivo techniques. We have identified nsp15 inhibition by the drugs pibrentasvir and atovaquone which effectively inhibit SARS-CoV-2 and HCoV-OC43 at low micromolar concentrations in cell cultures. Furthermore, atovaquone, but not pibrentasvir, is observed to modulate HCoV-OC43 dsRNA and infection in a manner consistent with nsp15 inhibition. Although neither pibrentasvir nor atovaquone translate to clinical efficacy in a murine prophylaxis model of SARS-CoV-2 infection, atovaquone may serve as a basis for the design of future nsp15 inhibitors.
Topics: Animals; Mice; SARS-CoV-2; COVID-19; Atovaquone; Endoribonucleases; Coronavirus OC43, Human
PubMed: 37766247
DOI: 10.3390/v15091841 -
Confining Prepared Ultrasmall Nanozymes Loading ATO for Lung Cancer Catalytic Therapy/Immunotherapy.Advanced Materials (Deerfield Beach,... Nov 2023Nanozymes with inherent enzyme-mimicking catalytic properties combat malignant tumor progression via catalytic therapy, while the therapeutic efficacy still needs to be...
Nanozymes with inherent enzyme-mimicking catalytic properties combat malignant tumor progression via catalytic therapy, while the therapeutic efficacy still needs to be improved. In this work, ultrasmall platinum nanozymes (nPt) in a confined domain of a wormlike pore channel in gold nanobipyramidal-mesoporous silica dioxide nanocomposites, producing nanozyme carriers AP-mSi with photoenhanced peroxidase ability, are innovatively synthesized. Afterward, based on the prepared AP-mSi, a lung-cancer nanozymes probe (AP-HAI) is ingeniously produced by removing the SiO template, modifying human serum albumin, and loading atovaquone molecules (ATO) as well as IR780. Under NIR light irradiation, inner AuP and IR780 collaborate for photothermal process, thus facilitating the peroxidase-like catalytic process of H O . Additionally, loaded ATO, a cell respiration inhibitor, can impair tumor respiration metabolism and cause oxygen retention, hence enhancing IR780's photodynamic therapy (PDT) effectiveness. As a result, IR780's PDT and nPt nanozymes' photoenhanced peroxidase-like ability endow probes a high ROS productivity, eliciting antitumor immune responses to destroy tumor tissue. Systematic studies reveal that the obvious reactive oxygen species (ROS) generation is obtained by the strategy of using nPt nanozymes and reducing oxygen consumption by ATO, which in turn enables lung-cancer synergetic catalytic therapy/immunogenic-cell-death-based immunotherapy. The results of this work would provide theoretical justification for the practical use of photoenhanced nanozyme probes.
Topics: Humans; Lung Neoplasms; Reactive Oxygen Species; Silicon Dioxide; Neoplasms; Immunotherapy; Lung; Peroxidases; Cell Line, Tumor
PubMed: 37748441
DOI: 10.1002/adma.202303722 -
Expert Opinion on Therapeutic Targets 2023Drugs targeting mitochondria are emerging as promising antitumor therapeutics in preclinical models. However, a few of these drugs have shown clinical toxicity.... (Review)
Review
INTRODUCTION
Drugs targeting mitochondria are emerging as promising antitumor therapeutics in preclinical models. However, a few of these drugs have shown clinical toxicity. Developing mitochondria-targeted modified natural compounds and US FDA-approved drugs with increased therapeutic index in cancer is discussed as an alternative strategy.
AREAS COVERED
Triphenylphosphonium cation (TPP)-based drugs selectively accumulate in the mitochondria of cancer cells due to their increased negative membrane potential, target the oxidative phosphorylation proteins, inhibit mitochondrial respiration, and inhibit tumor proliferation. TPP-based drugs exert minimal toxic side effects in rodents and humans. These drugs can sensitize radiation and immunotherapies.
EXPERT OPINION
TPP-based drugs targeting the tumor mitochondrial electron transport chain are a new class of oxidative phosphorylation inhibitors with varying antiproliferative and antimetastatic potencies. Some of these TPP-based agents, which are synthesized from naturally occurring molecules and FDA-approved drugs, have been tested in mice and did not show notable toxicity, including neurotoxicity, when used at doses under the maximally tolerated dose. Thus, more effort should be directed toward the clinical translation of TPP-based OXPHOS-inhibiting drugs in cancer prevention and treatment.
Topics: Humans; Mice; Animals; Mitochondria; Oxidative Phosphorylation; Neoplasms; Drug Delivery Systems; Antineoplastic Agents
PubMed: 37736880
DOI: 10.1080/14728222.2023.2261631 -
Emerging Infectious Diseases Oct 2023A 55-year-old man sought treatment for an uncomplicated febrile illness after returning to Canada from the Philippines. A suspected diagnosis of Plasmodium knowlesi... (Review)
Review
A 55-year-old man sought treatment for an uncomplicated febrile illness after returning to Canada from the Philippines. A suspected diagnosis of Plasmodium knowlesi infection was confirmed by PCR, and treatment with atovaquone/proguanil brought successful recovery. We review the evolving epidemiology of P. knowlesi malaria in the Philippines, specifically within Palawan Island.
Topics: Male; Humans; Middle Aged; Philippines; Plasmodium knowlesi; Malaria; Canada; Polymerase Chain Reaction
PubMed: 37735805
DOI: 10.3201/eid2910.230809 -
Advanced Materials (Deerfield Beach,... Jan 2024Taking the significance of the special microenvironment for tumor cell survival into account, disrupting tumor redox homeostasis is highly prospective for improving...
Taking the significance of the special microenvironment for tumor cell survival into account, disrupting tumor redox homeostasis is highly prospective for improving therapeutic efficacy. Herein, a multifunctional 2D vanadium-based MXene nanoplatform, V C /atovaquone@bovine albumin (V C /ATO@BSA, abbreviated as VAB) has been elaborately constructed for ATO-enhanced nanozyme catalytic/photothermal therapy. The redox homeostasis within the tumor cells is eventually disrupted, showing a remarkable anti-tumor effect. The VAB nanoplatform with mixed vanadium valence states can induce a cascade of catalyzed reactions in the tumor microenvironment, generating plenty of reactive oxygen species (ROS) with effective glutathione consumption to amplify oxidative stress. Meanwhile, the stable and strong photothermal effect of VAB under near-infrared irradiation not only causes the necrosis of tumor cells, but also improves its peroxidase-like activity. In addition, the release of ATO can effectively alleviate endogenous oxygen consumption to limit triphosadenine formation and inhibit mitochondrial respiration. As a result, the expression of heat shock proteins is effectively suppressed to overcome thermoresistance and the production of ROS can be further promoted due to mitochondrial injury. Moreover, VAB also presents high photoacoustic and photothermal imaging performances. In brief, the multifunctional nanoplatform can provide ATO-enhanced nanozyme catalytic/photothermal therapy with broadening the biomedical applications of vanadium-based MXene.
Topics: Animals; Cattle; Photothermal Therapy; Vanadium; Prospective Studies; Reactive Oxygen Species; Homeostasis; Oxidation-Reduction; Neoplasms; Catalysis; Tumor Microenvironment; Cell Line, Tumor; Hydrogen Peroxide; Nitrites; Transition Elements
PubMed: 37732568
DOI: 10.1002/adma.202307115