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1.
Bio Protoc ; 14(13): e5026, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-39007161

RESUMO

Diseases caused by trypanosomatid parasites remain a significant unmet medical need for millions of people globally. Trypanosomatid parasites such as Trypanosoma cruzi and subspecies of Trypanosoma brucei cause Chagas disease and human African trypanosomiasis (HAT), respectively. Although efforts to find novel treatments have been successful for HAT, Chagas disease is still treated with decades-old therapies that suffer from long treatment durations and severe safety concerns. We recently described the identification and characterization of the cyanotriazole compound class that kills trypanosomes, in vitro and in vivo, by selective inhibition of the trypanosome nuclear topoisomerase II enzyme. To evaluate whether inhibition of the topoisomerase II enzyme led to parasite death due to lethal double-strand DNA breaks, we developed assays for detecting DNA damage in both intracellular amastigotes of T. cruzi and bloodstream-form T. brucei by using the canonical DNA damage marker γH2A. Herein, this article describes the protocols for detecting DNA damage using an immunofluorescence assessment of γH2A by microscopy in trypanosome parasites. Key features • Immunofluorescence-based assay to detect the γH2A response in T. brucei and T. cruzi parasites. • Robust DNA damage pathway-based cellular assays to evaluate topoisomerase II poisons' ability to cause DNA damage. • A 384-well plate-based T. cruzi protocol allows high-resolution and high-throughput evaluation of compounds that cause DNA damage by measuring γH2A in intracellular parasites. • This assay could be modifiable for evaluation of DNA damage responses in various intracellular and extracellular eukaryotic pathogens.

2.
Proc (Bayl Univ Med Cent) ; 37(2): 218-226, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38343489

RESUMO

Background: In March 2022, a COVID-19 outbreak disrupted the global supply of iodine contrast media (ICM). Healthcare systems implemented contrast-saving strategies to maintain their remaining ICM supplies. This study sought to determine the impact of contrast shortage on the incidence of contrast-associated acute kidney injury (CA-AKI). Methods: This was a retrospective study of 265 patients undergoing 278 percutaneous coronary interventions (PCI) during 4-month periods prior to (9/1/2021 to 12/31/2021) and during (5/1/2022 to 8/31/2022) contrast shortage at a single center. The primary endpoint was the incidence of CA-AKI between study periods. Results: A total of 148 and 130 PCIs were performed before and during contrast shortage, respectively. The incidence of CA-AKI significantly decreased from 11.5% to 4.6% during contrast shortage (P = 0.04). During the shortage, average contrast volume per PCI was significantly lower (123 ± 62 mL vs 88 ± 46 mL, P < 0.001), while coronary imaging was significantly higher (34.3% vs 50%, P = 0.009) compared to preshortage. All-cause mortality at discharge was comparable between study periods (2.8% vs 3.3%, respectively; P = 0.90). Conclusion: The scarcity of ICM for PCI procedures in this single-center experience was associated with a significant increase in the utilization of intravascular imaging and a significant reduction in CA-AKI.

3.
Science ; 380(6652): 1349-1356, 2023 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-37384702

RESUMO

Millions who live in Latin America and sub-Saharan Africa are at risk of trypanosomatid infections, which cause Chagas disease and human African trypanosomiasis (HAT). Improved HAT treatments are available, but Chagas disease therapies rely on two nitroheterocycles, which suffer from lengthy drug regimens and safety concerns that cause frequent treatment discontinuation. We performed phenotypic screening against trypanosomes and identified a class of cyanotriazoles (CTs) with potent trypanocidal activity both in vitro and in mouse models of Chagas disease and HAT. Cryo-electron microscopy approaches confirmed that CT compounds acted through selective, irreversible inhibition of trypanosomal topoisomerase II by stabilizing double-stranded DNA:enzyme cleavage complexes. These findings suggest a potential approach toward successful therapeutics for the treatment of Chagas disease.


Assuntos
Doença de Chagas , Inibidores da Topoisomerase II , Triazóis , Trypanosoma , Tripanossomíase Africana , Animais , Humanos , Camundongos , Doença de Chagas/tratamento farmacológico , Microscopia Crioeletrônica , DNA Topoisomerases Tipo II/metabolismo , Trypanosoma/efeitos dos fármacos , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologia , Inibidores da Topoisomerase II/uso terapêutico , Triazóis/química , Triazóis/farmacologia , Triazóis/uso terapêutico , Tripanossomíase Africana/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos
4.
Cureus ; 15(4): e37140, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37153271

RESUMO

We present a case of a 51-year-old female who presented for evaluation of a large scalp mass found to have a different quartet of vascular malformations- a persistent scalp arteriovenous malformation (sAVM) with sinus pericranii, an inoperable intracranial SM-V brain arteriovenous malformation (bAVM), and a Cognard I dural arteriovenous fistula (dAVF). This is the first reported instance with four distinct vascular pathologies. We review the etiologies of multiple vascular abnormalities in the cerebral circulation that could contribute to this patient's findings and review strategies for treatment. We conducted a retrospective review of the clinical and angiographic records for a single adult female patient, including a management approach and an in-depth literature review. Given the high baseline vascularity of these complex lesions, surgery was not considered the initial therapy. We focused primarily on the sAVM with a staged embolization involving both transarterial and transvenous approaches. Transarterial coil embolizes 5 feeding artery branches of the right external carotid artery, followed by transvenous coil embolization into the common venous pouch accessed through the transosseous sinus pericranii via the SSS, dramatically reduced the size and filling of the large sAVM and eliminated a significant source of hypertensive venous outflow. Serial endovascular treatments of her sAVM led to a significant reduction in size and pulsatility, and the pain from tenderness to palpation was concurrently decreased. Despite multiple treatments, serial angiographic evaluations of her scalp lesion showed continued new development of collaterals. Ultimately the patient elected to forego further treatment for her sAVM. To our knowledge, there has not been another report of a single adult patient with a quartet of vascular malformations in the literature. Treatment paradigms for sAVMs are limited to case reports and small series; however, we purport that the most successful therapeutic approaches are multimodal and likely should incorporate surgical resection when feasible. We emphasize the caution required for patients with multiple other underlying intracranial vascular malformations. The altered intracranial flow dynamics can drastically hinder the success of a unimodal approach involving endovascular therapy alone.

5.
Trends Parasitol ; 39(4): 260-271, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36803572

RESUMO

While prevention is a bedrock of public health, innovative therapeutics are needed to complement the armamentarium of interventions required to achieve disease control and elimination targets for neglected diseases. Extraordinary advances in drug discovery technologies have occurred over the past decades, along with accumulation of scientific knowledge and experience in pharmacological and clinical sciences that are transforming many aspects of drug R&D across disciplines. We reflect on how these advances have propelled drug discovery for parasitic infections, focusing on malaria, kinetoplastid diseases, and cryptosporidiosis. We also discuss challenges and research priorities to accelerate discovery and development of urgently needed novel antiparasitic drugs.


Assuntos
Malária , Doenças Parasitárias , Humanos , Descoberta de Drogas , Doenças Parasitárias/tratamento farmacológico , Antiparasitários/farmacologia , Antiparasitários/uso terapêutico , Malária/tratamento farmacológico , Tecnologia
6.
J Med Chem ; 65(17): 11776-11787, 2022 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-35993839

RESUMO

Human African Trypanosomiasis (HAT) is a vector-borne disease caused by kinetoplastid parasites of the Trypanosoma genus. The disease proceeds in two stages, with a hemolymphatic blood stage and a meningo-encephalic brain stage. In the latter stage, the parasite causes irreversible damage to the brain leading to sleep cycle disruption and is fatal if untreated. An orally bioavailable treatment is highly desirable. In this study, we present a brain-penetrant, parasite-selective 20S proteasome inhibitor that was rapidly optimized from an HTS singleton hit to drug candidate compound 7 that showed cure in a stage II mouse efficacy model. Here, we describe hit expansion and lead optimization campaign guided by cryo-electron microscopy and an in silico model to predict the brain-to-plasma partition coefficient Kp as an important parameter to prioritize compounds for synthesis. The model combined with in vitro and in vivo experiments allowed us to advance compounds with favorable unbound brain-to-plasma ratios (Kp,uu) to cure a CNS disease such as HAT.


Assuntos
Quinolinas , Trypanosoma , Tripanossomíase Africana , Animais , Microscopia Crioeletrônica , Modelos Animais de Doenças , Humanos , Camundongos , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêutico , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Tripanossomíase Africana/tratamento farmacológico , Tripanossomíase Africana/parasitologia
7.
J Physiol ; 599(24): 5465-5484, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34783016

RESUMO

Ageing and challenging signal-in-noise conditions are known to engage the use of cortical resources to help maintain speech understanding. Extensive corticothalamic projections are thought to provide attentional, mnemonic and cognitive-related inputs in support of sensory inferior colliculus (IC) inputs to the medial geniculate body (MGB). Here we show that a decrease in modulation depth, a temporally less distinct periodic acoustic signal, leads to a jittered ascending temporal code, changing MGB unit responses from adapting responses to responses showing repetition enhancement, posited to aid identification of important communication and environmental sounds. Young-adult male Fischer Brown Norway rats, injected with the inhibitory opsin archaerhodopsin T (ArchT) into the primary auditory cortex (A1), were subsequently studied using optetrodes to record single-units in MGB. Decreasing the modulation depth of acoustic stimuli significantly increased repetition enhancement. Repetition enhancement was blocked by optical inactivation of corticothalamic terminals in MGB. These data support a role for corticothalamic projections in repetition enhancement, implying that predictive anticipation could be used to improve neural representation of weakly modulated sounds. KEY POINTS: In response to a less temporally distinct repeating sound with low modulation depth, medial geniculate body (MGB) single units show a switch from adaptation towards repetition enhancement. Repetition enhancement was reversed by blockade of MGB inputs from the auditory cortex. Collectively, these data argue that diminished acoustic temporal cues such as weak modulation engage cortical processes to enhance coding of those cues in auditory thalamus.


Assuntos
Córtex Auditivo , Corpos Geniculados , Estimulação Acústica , Animais , Masculino , Neurônios , Ratos , Reprodutibilidade dos Testes
8.
mBio ; 12(3): e0068721, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34128702

RESUMO

During mitosis, eukaryotic cells must duplicate and separate their chromosomes in a precise and timely manner. The apparatus responsible for this is the kinetochore, which is a large protein structure that links chromosomal DNA and spindle microtubules to facilitate chromosome alignment and segregation. The proteins that comprise the kinetochore in the protozoan parasite Trypanosoma brucei are divergent from yeast and mammals and comprise an inner kinetochore complex composed of 24 distinct proteins (KKT1 to KKT23, KKT25) that include four protein kinases, CLK1 (KKT10), CLK2 (KKT19), KKT2, and KKT3. We recently reported the identification of a specific trypanocidal inhibitor of T. brucei CLK1, an amidobenzimidazole, AB1. We now show that chemical inhibition of CLK1 with AB1 impairs inner kinetochore recruitment and compromises cell cycle progression, leading to cell death. Here, we show that KKT2 is a substrate for CLK1 and identify phosphorylation of S508 by CLK1 to be essential for KKT2 function and for kinetochore assembly. Additionally, KKT2 protein kinase activity is required for parasite proliferation but not for assembly of the inner kinetochore complex. We also show that chemical inhibition of the aurora kinase AUK1 does not affect CLK1 phosphorylation of KKT2, indicating that AUK1 and CLK1 are in separate regulatory pathways. We propose that CLK1 is part of a divergent signaling cascade that controls kinetochore function via phosphorylation of the inner kinetochore protein kinase KKT2. IMPORTANCE In eukaryotic cells, kinetochores are large protein complexes that link chromosomes to dynamic microtubule tips, ensuring proper segregation and genomic stability during cell division. Several proteins tightly coordinate kinetochore functions, including the protein kinase aurora kinase B. The kinetochore has diverse evolutionary roots. For example, trypanosomatids, single-cell parasitic protozoa that cause several neglected tropical diseases, possess a unique repertoire of kinetochore components whose regulation during the cell cycle remains unclear. Here, we shed light on trypanosomatid kinetochore biology by showing that the protein kinase CLK1 coordinates the assembly of the inner kinetochore by phosphorylating one of its components, KKT2, allowing the timely spatial recruitment of the rest of the kinetochore proteins and posterior attachment to microtubules in a process that is aurora kinase B independent.


Assuntos
Regulação da Expressão Gênica , Cinetocoros/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas de Protozoários/metabolismo , Transdução de Sinais , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Mitose , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , Proteínas de Protozoários/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
9.
J Med Chem ; 64(13): 9444-9457, 2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34138573

RESUMO

Screening of a library of small polar molecules against Mycobacterium tuberculosis (Mtb) led to the identification of a potent benzoheterocyclic oxime carbamate hit series. This series was subjected to medicinal chemistry progression underpinned by structure-activity relationship studies toward identifying a compound for proof-of-concept studies and defining a lead optimization strategy. Carbamate and free oxime frontrunner compounds with good stability in liver microsomes and no hERG channel inhibition liability were identified and evaluated in vivo for pharmacokinetic properties. Mtb-mediated permeation and metabolism studies revealed that the carbamates were acting as prodrugs. Toward mechanism of action elucidation, selected compounds were tested in biology triage assays to assess their activity against known promiscuous targets. Taken together, these data suggest a novel yet unknown mode of action for these antitubercular hits.


Assuntos
Antituberculosos/farmacologia , Carbamatos/farmacologia , Compostos Heterocíclicos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Oximas/farmacologia , Antituberculosos/química , Antituberculosos/metabolismo , Carbamatos/química , Carbamatos/metabolismo , Relação Dose-Resposta a Droga , Compostos Heterocíclicos/química , Compostos Heterocíclicos/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/metabolismo , Oximas/química , Oximas/metabolismo , Relação Estrutura-Atividade
10.
Cancer Res ; 81(2): 315-331, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33067265

RESUMO

DZIP3/hRUL138 is a poorly characterized RNA-binding RING E3-ubiquitin ligase with functions in embryonic development. Here we demonstrate that DZIP3 is a crucial driver of cancer cell growth, migration, and invasion. In mice and zebrafish cancer models, DZIP3 promoted tumor growth and metastasis. In line with these results, DZIP3 was frequently overexpressed in several cancer types. Depletion of DZIP3 from cells resulted in reduced expression of Cyclin D1 and a subsequent G1 arrest and defect in cell growth. Mechanistically, DZIP3 utilized its two different domains to interact and stabilize Cyclin D1 both at mRNA and protein levels. Using an RNA-binding lysine-rich region, DZIP3 interacted with the AU-rich region in 3' untranslated region of Cyclin D1 mRNA and stabilized it. Using a RING E3-ligase domain, DZIP3 interacted and increased K63-linked ubiquitination of Cyclin D1 protein to stabilize it. Remarkably, DZIP3 interacted with, ubiquitinated, and stabilized Cyclin D1 predominantly in the G1 phase of the cell cycle, where it is needed for cell-cycle progression. In agreement with this, a strong positive correlation of mRNA expression between DZIP3 and Cyclin D1 in different cancer types was observed. Additionally, DZIP3 regulated several cell cycle proteins by modulating the Cyclin D1-E2F axes. Taken together, this study demonstrates for the first time that DZIP3 uses a unique two-pronged mechanism in its stabilization of Cyclin D1 to drive cell-cycle and cancer progression. SIGNIFICANCE: These findings show that DZIP3 is a novel driver of cell-cycle and cancer progression via its control of Cyclin D1 mRNA and protein stability in a cell-cycle phase-dependent manner. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/2/315/F1.large.jpg.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Ciclina D1/química , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/secundário , Estabilidade de RNA , Proteínas de Ligação a RNA/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Movimento Celular , Proliferação de Células , Ciclina D1/genética , Ciclina D1/metabolismo , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação , Prognóstico , Proteínas de Ligação a RNA/genética , Células Tumorais Cultivadas , Ubiquitina-Proteína Ligases/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-Zebra
11.
Int J Mol Sci ; 21(23)2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33271944

RESUMO

Pancreatic cancer (pancreatic ductal adenocarcinoma (PDAC/PC)) has been an aggressive disease that is associated with early metastases. It is characterized by dense and collagenous desmoplasia/stroma, predominantly produced by pancreatic stellate cells (PSCs). PSCs interact with cancer cells as well as other stromal cells, facilitating disease progression. A candidate growth factor pathway that may mediate this interaction is the hepatocyte growth factor (HGF)/c-MET pathway. HGF is produced by PSCs and its receptor c-MET is expressed on pancreatic cancer cells and endothelial cells. The current review discusses the role of the MET/HGF axis in tumour progression and dissemination of pancreatic cancer. Therapeutic approaches that were developed targeting either the ligand (HGF) or the receptor (c-MET) have not been shown to translate well into clinical settings. We discuss a two-pronged approach of targeting both the components of this pathway to interrupt the stromal-tumour interactions, which may represent a potential therapeutic strategy to improve outcomes in PC.


Assuntos
Fator de Crescimento de Hepatócito/genética , Fator de Crescimento de Hepatócito/metabolismo , Neoplasias Pancreáticas/etiologia , Neoplasias Pancreáticas/metabolismo , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Animais , Biomarcadores Tumorais , Regulação Neoplásica da Expressão Gênica , Humanos , Estadiamento de Neoplasias , Neovascularização Patológica , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/terapia , Transdução de Sinais , Microambiente Tumoral
12.
Am J Cardiol ; 132: 93-99, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32782067

RESUMO

To compare outcomes of ultrasound guidance (USG) versus fluoroscopy roadmap guidance (FG) angiography for femoral artery access in patients who underwent transfemoral (TF) transcatheter aortic valve implantation (TAVI) to determine whether routine USG use was associated with fewer vascular complications. Vascular complications are the most frequent procedural adverse events associated with TAVI. USG may provide a decreased rate of access site complications during vascular access compared with FG. Patients who underwent TF TAVI between July 2012 and July 2017 were reviewed and outcomes were compared. Vascular complications were categorized by Valve Academic Research Consortium-2 criteria and analyzed by a multivariable logistic regression adjusting for potential confounding risk factors including age, gender, body mass index, peripheral vascular disease, Society of Thoracic Surgeons score and sheath to femoral artery ratio. Of the 612 TAVI patients treated, 380 (63.1%) were performed using USG for access. Routine use of USG began in March 2015 and increased over time. Vascular complications occurred in 63 (10.3%) patients and decreased from 20% to 3.9% during the study period. There were fewer vascular complications with USG versus FG (7.9% vs 14.2%, p = 0.014). After adjusting for potential confounding risk factors that included newer valve systems, smaller sheath sizes and lower risk patients, there was still a 49% reduction in vascular complications with USG (odds ratio 0.51, 95% confidence interval 0.29 to 0.88, p = 0.02). In conclusion, USG for TF TAVI was associated with reduced vascular access site complications compared with FG access even after accounting for potential confounding risk factors and should be considered for routine use for TF TAVI.


Assuntos
Estenose da Valva Aórtica/cirurgia , Valva Aórtica/cirurgia , Fluoroscopia/métodos , Cirurgia Assistida por Computador/métodos , Substituição da Valva Aórtica Transcateter/métodos , Ultrassonografia/métodos , Idoso , Idoso de 80 Anos ou mais , Angiografia , Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/diagnóstico , Feminino , Artéria Femoral , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
13.
Nat Microbiol ; 5(10): 1207-1216, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32661312

RESUMO

The kinetochore is a macromolecular structure that assembles on the centromeres of chromosomes and provides the major attachment point for spindle microtubules during mitosis. In Trypanosoma brucei, the proteins that make up the kinetochore are highly divergent; the inner kinetochore comprises at least 20 distinct and essential proteins (KKT1-20) that include four protein kinases-CLK1 (also known as KKT10), CLK2 (also known as KKT19), KKT2 and KKT3. Here, we report the identification and characterization of the amidobenzimidazoles (AB) protein kinase inhibitors that show nanomolar potency against T. brucei bloodstream forms, Leishmania and Trypanosoma cruzi. We performed target deconvolution analysis using a selection of 29 T. brucei mutants that overexpress known essential protein kinases, and identified CLK1 as a primary target. Biochemical studies and the co-crystal structure of CLK1 in complex with AB1 show that the irreversible competitive inhibition of CLK1 is dependent on a Michael acceptor forming an irreversible bond with Cys 215 in the ATP-binding pocket, a residue that is not present in human CLK1, thereby providing selectivity. Chemical inhibition of CLK1 impairs inner kinetochore recruitment and compromises cell-cycle progression, leading to cell death. This research highlights a unique drug target for trypanosomatid parasitic protozoa and a new chemical tool for investigating the function of their divergent kinetochores.


Assuntos
Cinetocoros/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas de Protozoários/antagonistas & inibidores , Trypanosoma brucei brucei/efeitos dos fármacos , Animais , Biomarcadores , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Modelos Animais de Doenças , Expressão Gênica , Humanos , Imunofenotipagem , Cinetocoros/química , Camundongos , Conformação Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas de Protozoários/química , Relação Estrutura-Atividade
14.
J Med Chem ; 63(19): 10773-10781, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-32667203

RESUMO

Visceral leishmaniasis is responsible for up to 30,000 deaths every year. Current treatments have shortcomings that include toxicity and variable efficacy across endemic regions. Previously, we reported the discovery of GNF6702, a selective inhibitor of the kinetoplastid proteasome, which cleared parasites in murine models of leishmaniasis, Chagas disease, and human African trypanosomiasis. Here, we describe the discovery and characterization of LXE408, a structurally related kinetoplastid-selective proteasome inhibitor currently in Phase 1 human clinical trials. Furthermore, we present high-resolution cryo-EM structures of the Leishmania tarentolae proteasome in complex with LXE408, which provides a compelling explanation for the noncompetitive mode of binding of this novel class of inhibitors of the kinetoplastid proteasome.


Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Leishmaniose Visceral/tratamento farmacológico , Oxazóis/química , Oxazóis/farmacologia , Inibidores de Proteassoma/química , Inibidores de Proteassoma/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Animais , Antiprotozoários/uso terapêutico , Cães , Humanos , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/isolamento & purificação , Leishmania major/efeitos dos fármacos , Leishmania major/isolamento & purificação , Leishmaniose Visceral/parasitologia , Fígado/parasitologia , Macaca fascicularis , Camundongos , Camundongos Endogâmicos BALB C , Oxazóis/uso terapêutico , Inibidores de Proteassoma/uso terapêutico , Pirimidinas/uso terapêutico , Ratos , Ratos Sprague-Dawley , Triazóis/química
15.
Br J Cancer ; 122(10): 1486-1495, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32203220

RESUMO

BACKGROUND: Stromal-tumour interactions facilitate pancreatic cancer (PC) progression. The hepatocyte growth factor (HGF)/c-MET pathway is upregulated in PC and mediates the interaction between cancer cells and stromal pancreatic stellate cells (PSCs). This study assessed the effect of HGF/c-MET inhibition plus gemcitabine (G) on the progression of advanced PC. METHODS: Orthotopic PC was produced by implantation of luciferase-tagged human cancer cells + human PSCs into mouse pancreas. Tumours were allowed to develop without treatment for 4 weeks. Mice were then treated for 6 weeks with one of the following: IgG, G, HGF inhibitor (Hi), c-MET inhibitor (Ci), Hi + Ci, Hi + G, Ci + G, or Hi + Ci + G. RESULTS: Bioluminescence imaging showed similar tumour sizes in all mice at the initiation of treatments. Triple therapy (Hi + Ci + G): (1) completely eliminated metastasis; (2) significantly reduced tumour size as assessed by bioluminescence and at necropsy; (3) significantly reduced proliferating cancer cell density and stem cell marker DCLK1 expression in tumours. In vitro 3D culture studies supported our in vivo findings. CONCLUSION: Even at an advanced disease stage, a two-pronged approach, targeting (a) HGF/c-MET with relevant inhibitors and (b) cancer cells with chemotherapy, completely eliminated metastasis and significantly decreased tumour growth, suggesting that this is a promising treatment approach for PC.


Assuntos
Carcinogênese/efeitos dos fármacos , Fator de Crescimento de Hepatócito/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/genética , Neoplasias Pancreáticas/tratamento farmacológico , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Animais , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Quinases Semelhantes a Duplacortina , Fator de Crescimento de Hepatócito/genética , Humanos , Imunoglobulina G/farmacologia , Camundongos , Metástase Neoplásica , Estadiamento de Neoplasias , Células-Tronco Neoplásicas , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Células Estreladas do Pâncreas/efeitos dos fármacos , Células Estreladas do Pâncreas/metabolismo , Proteínas Proto-Oncogênicas c-met/genética , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Gencitabina
16.
Trop Med Infect Dis ; 5(1)2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32092897

RESUMO

The twentieth century ended with human African trypanosomiasis (HAT) epidemics raging across many parts of Africa. Resistance to existing drugs was emerging, and many programs aiming to contain the disease had ground to a halt, given previous success against HAT and the competing priorities associated with other medical crises ravaging the continent. A series of dedicated interventions and the introduction of innovative routes to develop drugs, involving Product Development Partnerships, has led to a dramatic turnaround in the fight against HAT caused by Trypanosoma brucei gambiense. The World Health Organization have been able to optimize the use of existing tools to monitor and intervene in the disease. A promising new oral medication for stage 1 HAT, pafuramidine maleate, ultimately failed due to unforeseen toxicity issues. However, the clinical trials for this compound demonstrated the possibility of conducting such trials in the resource-poor settings of rural Africa. The Drugs for Neglected Disease initiative (DNDi), founded in 2003, has developed the first all oral therapy for both stage 1 and stage 2 HAT in fexinidazole. DNDi has also brought forward another oral therapy, acoziborole, potentially capable of curing both stage 1 and stage 2 disease in a single dosing. In this review article, we describe the remarkable successes in combating HAT through the twenty first century, bringing the prospect of the elimination of this disease into sight.

17.
Trop Med Infect Dis ; 5(1)2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32079320

RESUMO

Current anti-trypanosomal therapies suffer from problems of longer treatment duration, toxicity and inadequate efficacy, hence there is a need for safer, more efficacious and 'easy to use' oral drugs. Previously, we reported the discovery of the triazolopyrimidine (TP) class as selective kinetoplastid proteasome inhibitors with in vivo efficacy in mouse models of leishmaniasis, Chagas Disease and African trypanosomiasis (HAT). For the treatment of HAT, development compounds need to have excellent penetration to the brain to cure the meningoencephalic stage of the disease. Here we describe detailed biological and pharmacological characterization of triazolopyrimidine compounds in HAT specific assays. The TP class of compounds showed single digit nanomolar potency against Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense strains. These compounds are trypanocidal with concentration-time dependent kill and achieved relapse-free cure in vitro. Two compounds, GNF6702 and a new analog NITD689, showed favorable in vivo pharmacokinetics and significant brain penetration, which enabled oral dosing. They also achieved complete cure in both hemolymphatic (blood) and meningoencephalic (brain) infection of human African trypanosomiasis mouse models. Mode of action studies on this series confirmed the 20S proteasome as the target in T. brucei. These proteasome inhibitors have the potential for further development into promising new treatment for human African trypanosomiasis.

18.
Pancreatology ; 20(3): 409-418, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31928917

RESUMO

Tumour-stromal interactions have now been acknowledged to play a major role in pancreatic cancer (PC) progression. The abundant collagenous stroma is produced by a specific cell type in the pancreas-the pancreatic stellate cell (PSC). Pancreatic stellate cells (PSCs) are a unique resident cell type of pancreas and with a critical role in both healthy and diseased pancreas. Accumulating evidence indicates that PSCs interact closely with cancer cells as well as with other cell types of the stroma such as immune cells, endothelial cells and neuronal cells, to set up a growth permissive microenvironment for pancreatic tumours, which facilitates local tumour growth as well as distant metastasis. Consequently, recent work in the field has focused on the development of novel therapeutic approaches targeting the stroma to inhibit PC progression. Such a multi-pronged approach targeting both tumour and stromal elements of PC has been successfully applied in pre-clinical settings. The challenge now is to translate the pre-clinical findings into the clinical setting to achieve better outcomes for pancreatic cancer patients.


Assuntos
Neoplasias Pancreáticas/patologia , Células Estreladas do Pâncreas/patologia , Progressão da Doença , Humanos , Microambiente Tumoral
19.
Proc (Bayl Univ Med Cent) ; 34(1): 5-10, 2020 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-33456136

RESUMO

Enhanced recovery after surgery (ERAS) protocols are gaining wide acceptance. We evaluated ERAS protocol implementation in transfemoral transcatheter aortic valve replacement (TAVR) patients. The ERAS protocol included (1) moderate sedation or general anesthesia with on-table extubation, (2) no pulmonary artery or urinary catheters, (3) arterial line removal within 4 hours, (4) no postoperative narcotics, (5) mobilization at 4 hours and ambulation within 8 hours, and (6) antihypertensive reinstitution without nodal blockers. Patients who received TAVR before and after ERAS implementation were compared (N = 121 and N = 368, respectively). The primary endpoint was total hospital length of stay (LOS). ERAS patients had a lower mean Society of Thoracic Surgeons predicted risk of mortality (6.7% vs 7.5%; P = 0.04). Unadjusted analysis demonstrated that ERAS was associated with significantly decreased mean LOS (2.8 vs 4.0 days, P < 0.001), decreased 30-day mortality (0.8% vs 5.0%; P = 0.003), and increased discharge home (90.2% vs 79.3%, P = 0.002) with no increase in 30-day readmission (11.1% vs 14.0%, P = 0.39). After risk adjustment, ERAS patients had a 1.87-day shorter LOS (P = 0.001) and trended toward increased discharge home (odds ratio 1.76, P = 0.078) without increased readmission (odds ratio 0.74, P = 0.4). An ERAS protocol for TAVR is safe and is associated with shorter LOS without increased readmission.

20.
ACS Infect Dis ; 6(1): 3-13, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31808676

RESUMO

In May 2019, the Wellcome Centre for Anti-Infectives Research (WCAIR) at the University of Dundee, UK, held an international conference with the aim of discussing some key questions around discovering new medicines for infectious diseases and a particular focus on diseases affecting Low and Middle Income Countries. There is an urgent need for new drugs to treat most infectious diseases. We were keen to see if there were lessons that we could learn across different disease areas and between the preclinical and clinical phases with the aim of exploring how we can improve and speed up the drug discovery, translational, and clinical development processes. We started with an introductory session on the current situation and then worked backward from clinical development to combination therapy, pharmacokinetic/pharmacodynamic (PK/PD) studies, drug discovery pathways, and new starting points and targets. This Viewpoint aims to capture some of the learnings.


Assuntos
Controle de Doenças Transmissíveis , Doenças Transmissíveis/tratamento farmacológico , Congressos como Assunto , Terapia Combinada , Doenças Transmissíveis/epidemiologia , Descoberta de Drogas , Avaliação Pré-Clínica de Medicamentos , Infecções por HIV/tratamento farmacológico , Humanos , Pobreza , Reino Unido
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