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1.
J Imaging ; 10(6)2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38921604

RESUMO

X-ray Fluorescence Computed Tomography (XFCT) is an emerging non-invasive imaging technique providing high-resolution molecular-level data. However, increased sensitivity with current benchtop X-ray sources comes at the cost of high radiation exposure. Artificial Intelligence (AI), particularly deep learning (DL), has revolutionized medical imaging by delivering high-quality images in the presence of noise. In XFCT, traditional methods rely on complex algorithms for background noise reduction, but AI holds promise in addressing high-dose concerns. We present an optimized Swin-Conv-UNet (SCUNet) model for background noise reduction in X-ray fluorescence (XRF) images at low tracer concentrations. Our method's effectiveness is evaluated against higher-dose images, while various denoising techniques exist for X-ray and computed tomography (CT) techniques, only a few address XFCT. The DL model is trained and assessed using augmented data, focusing on background noise reduction. Image quality is measured using peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM), comparing outcomes with 100% X-ray-dose images. Results demonstrate that the proposed algorithm yields high-quality images from low-dose inputs, with maximum PSNR of 39.05 and SSIM of 0.86. The model outperforms block-matching and 3D filtering (BM3D), block-matching and 4D filtering (BM4D), non-local means (NLM), denoising convolutional neural network (DnCNN), and SCUNet in both visual inspection and quantitative analysis, particularly in high-noise scenarios. This indicates the potential of AI, specifically the SCUNet model, in significantly improving XFCT imaging by mitigating the trade-off between sensitivity and radiation exposure.

2.
Int J Mol Sci ; 25(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38731956

RESUMO

X-ray fluorescence imaging (XFI) can localize diagnostic or theranostic entities utilizing nanoparticle (NP)-based probes at high resolution in vivo, in vitro, and ex vivo. However, small-animal benchtop XFI systems demonstrating high spatial resolution (variable from sub-millimeter to millimeter range) in vivo are still limited to lighter elements (i.e., atomic number Z≤45). This study investigates the feasibility of focusing hard X-rays from solid-target tubes using ellipsoidal lens systems composed of mosaic graphite crystals with the aim of enabling high-resolution in vivo XFI applications with mid-Z (42≤Z≤64) elements. Monte Carlo simulations are performed to characterize the proposed focusing-optics concept and provide quantitative predictions of the XFI sensitivity, in silico tumor-bearing mice models loaded with palladium (Pd) and barium (Ba) NPs. Based on simulation results, the minimum detectable total mass of PdNPs per scan position is expected to be on the order of a few hundred nanograms under in vivo conform conditions. PdNP masses as low as 150 ng to 50 ng could be detectable with a resolution of 600 µm when imaging abdominal tumor lesions across a range of low-dose (0.8 µGy) to high-dose (8 µGy) exposure scenarios. The proposed focusing-optics concept presents a potential step toward realizing XFI with conventional X-ray tubes for high-resolution applications involving interesting NP formulations.


Assuntos
Grafite , Grafite/química , Animais , Camundongos , Imagem Óptica/métodos , Método de Monte Carlo , Nanopartículas/química , Paládio/química , Simulação por Computador , Espectrometria por Raios X/métodos
4.
BMC Immunol ; 23(1): 53, 2022 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-36324077

RESUMO

BACKGROUND: Macrophages are mononuclear CD34+ antigen-presenting cells of defense mechanism and play dual roles in tumor burden. The immunomodulatory and their antitumor function of ß-defensin 2 is still unclear, despite the accumulating evidence of the response in infection. So, the aim of present study is to elucidate the role of ß-defensin 2 on the level of ROS, cytokines, chemokine expression in macrophages and antitumor function in breast cancer. METHOD: Swiss albino mice were used to harvest PEC macrophages and C127i breast cancer cells line for tumor model was used in this study. Macrophages were harvested and characterized by flow-cytometry using F4/80 and CD11c antibodies. MTT was performed to estimate cytotoxicity and dose optimization of ß-defensin 2. Oxidative stress was analyzed by H2O2 and NO estimation followed by iNOS quantified by q-PCR. Cytokines and chemokines estimation was done using q-PCR. Co-culture experiment was performed to study anti-tumor function using PI for cell cycle, Annexin -V and CFSE analysis for cell proliferation. RESULTS: PEC harvested macrophages were characterized by flow-cytometry using F4/80 and CD11c antibodies with the purity of 8% pure population of macrophages. It was found that 99% of cells viable at the maximum dose of 100 ng/ml of ß-defensin 2 in MTT. Levels of NO and H2O2 were found to be decreased in ß-defensin 2 as compared to control. Expression of cytokines of IFN-γ, IL-1α, TNF-α, TGF-ßwas found to be increased while IL-3 was decreased in ß-defensin 2 group as compared to control. Levels of chemokines CXCL-1, CXCL-5 and CCL5 increased in treated macrophages while CCL24 and CXCL-15 expression decreased. Adhesion receptor (CD32) and fusion receptor (CD204) were decreased in the ß-defensin 2 group as compared to control. Anti-tumor experiment was performed using co-culture experiment apoptosis (Annexin-V) was induced, cell cycle arrest in phage and cell proliferation of C127i cells was decreased. CONCLUSION: This is the first report of ß-defensin 2 modulates macrophage immunomodulatory and their antitumor function in breast cancer. ß-defensin 2 as a new therapeutic target for immunotherapy as an adjuvant in vaccines.


Assuntos
Neoplasias , beta-Defensinas , Animais , Camundongos , beta-Defensinas/metabolismo , beta-Defensinas/farmacologia , Peróxido de Hidrogênio , Macrófagos , Citocinas/metabolismo , Quimiocinas/metabolismo , Quimiocinas/farmacologia , Anexinas/metabolismo , Anexinas/farmacologia , Neoplasias/metabolismo
5.
J Cancer Prev ; 27(3): 170-181, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36258717

RESUMO

Emergence of radioresistance in prostate cancer (PCa) cells is a major obstacle in cancer therapy and contributes to the relapse of the disease. EGF receptor (EGFR) signaling plays an important role in the development of radioresistance. Herein, we have assessed the modulatory effects of silibinin on radiation-induced resistance via DNA repair pathways in EGFR-knockdown DU145 cells. shRNA-based silencing of EGFR was done in radioresistant human PCa DU145 cells and effects of ionizing radiation (IR) and silibinin were assessed using clonogenic and trypan blue assays. Furthermore, radiosensitizing effects of silibinin on PCa in context with EGFR were analyzed using flow cytometry, comet assay, and immunoblotting. Silibinin decreased the colony formation ability with an increased death of DU145 cells exposed to IR (5 Gray), with a concomitant decrease in Rad51 protein expression. Silibinin (25 µM) augmented the IR-induced cytotoxic effect in EGFR-knockdown PCa cells, along with induction of G2/M phase cell cycle arrest. Further, we studied homologous recombination (HR) and non-homologous end joining (NHEJ) pathways in silibinin-induced DNA double-strand breaks in EGFR-knockdown DU145 cells. Silibinin down-regulated the expression of Rad51 and DNA-dependent protein kinase proteins without any considerable effect on Ku70 and Ku80 in IR-exposed EGFR-knockdown PCa cells. The pro-survival signaling proteins, phospho-extracellular signal-regulated kinases (ERK)1/2, phospho-Akt and phospho-STAT3 were decreased by silibinin in EGFR-deficient PCa cells. These findings suggest a novel mechanism of silibinin-induced radiosensitization of PCa cells by targeting DNA repair pathways, HR and NHEJ, and suppressing the pro-survival signaling pathways, ERK1/2, Akt and STAT3, in EGFR-knockdown PCa cells.

6.
J Family Med Prim Care ; 11(1): 353-356, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35309645

RESUMO

While tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease among children, its first presentation in the third decade of life just after successful pregnancy outcome is extremely rare. In fact, survival of both child and mother having uncorrected TOF after noninstitutional delivery is unheard of. Herein, authors report a case of previously undiagnosed TOF associated with other midline congenital abnormalities, that is, nasal dermoid cyst and cleft palate, who presented for the first time with postpartum hemorrhage after an unsupervised home birth. To the best of our knowledge, this unique association has never been described before.

7.
Front Endocrinol (Lausanne) ; 12: 671946, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335466

RESUMO

A quantitative deficiency of normally functioning insulin-producing pancreatic beta cells is a major contributor to all common forms of diabetes. This is the underlying premise for attempts to replace beta cells in people with diabetes by pancreas transplantation, pancreatic islet transplantation, and transplantation of beta cells or pancreatic islets derived from human stem cells. While progress is rapid and impressive in the beta cell replacement field, these approaches are expensive, and for transplant approaches, limited by donor organ availability. For these reasons, beta cell replacement will not likely become available to the hundreds of millions of people around the world with diabetes. Since the large majority of people with diabetes have some residual beta cells in their pancreata, an alternate approach to reversing diabetes would be developing pharmacologic approaches to induce these residual beta cells to regenerate and expand in a way that also permits normal function. Unfortunately, despite the broad availability of multiple classes of diabetes drugs in the current diabetes armamentarium, none has the ability to induce regeneration or expansion of human beta cells. Development of such drugs would be transformative for diabetes care around the world. This picture has begun to change. Over the past half-decade, a novel class of beta cell regenerative small molecules has emerged: the DYRK1A inhibitors. Their emergence has tremendous potential, but many areas of uncertainty and challenge remain. In this review, we summarize the accomplishments in the world of beta cell regenerative drug development and summarize areas in which most experts would agree. We also outline and summarize areas of disagreement or lack of unanimity, of controversy in the field, of obstacles to beta cell regeneration, and of challenges that will need to be overcome in order to establish human beta cell regenerative drug therapeutics as a clinically viable class of diabetes drugs.


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Células Secretoras de Insulina/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Regeneração/efeitos dos fármacos , Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Humanos , Células Secretoras de Insulina/citologia , Quinases Dyrk
8.
J Pharm Bioallied Sci ; 13(Suppl 1): S180-S183, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34447070

RESUMO

BACKGROUND: Patients under palliative care and their caregivers often ignore the dental treatment and oral hygiene needs as a result of which they face many day to day problems, which include difficulty in chewing, halitosis, and dry mouth eventually deteriorating the quality of life. OBJECTIVE: The aim of this study is to understand the oral needs and oral health-related concerns of the patients under palliative care. METHODOLOGY: A total of eight patients agreed to enroll in the study. A detailed interview with oral examination, including Sillness and Loe Plaque Index and Decayed Missing and Filled Teeth (dmft) Index, was recorded. Patients were also given the treatment needed if willing for the same. RESULTS: In our study, we observed that the mean dmft scores of dentulous patients were 7.96 ± 3.35, and mean plaque score was 1.75 ± 2.12, which was significantly higher and further highlights the need for dental treatment. CONCLUSION: The patients under palliative care have many oral problems such as dry mouth, difficulty in eating, halitosis which needs to be addressed; hence, dental health plays an important role in improving the quality of life of these patients.

9.
Pediatr Cardiol ; 42(4): 891-897, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33511467

RESUMO

There is a need for a sensitive, safe, and cost-effective tool for coronary assessment among asymptomatic post-operative children who have undergone arterial switch operation (ASO) for transposition of great arteries (TGA). Adenosine stress echocardiography may be useful in assessing major structures as well for coronary functional assessment. Twenty-six children [median age 6.0 years; IQR 4.9-7.1 years, (22 boys)], who had undergone ASO at a median age of 40 days (IQR 30-75 days), were prospectively included. Left ventricular ejection fraction (LVEF) was calculated in both rest and stress studies (140 µg/kg/min of adenosine IV over 4 min), along with assessment of regional myocardial wall motion. Coronary flow reserve (CFR) was also measured in the left anterior descending artery (LAD). Technetium 99m-MIBI [0.2mCi/kg] was injected after 2 min of adenosine infusion. Adenosine infusion had to be stopped in two children, due to transient atrioventricular (AV) block. The LVEF increased from 55.87 ± 7.27 to 61.20 ± 7.70% (p < 0.001) with adenosine stress. No significant regional wall motion abnormality was seen in rest or stress. Distal LAD could not be visualized in four patients. Basal and peak coronary flow velocities were 41.51 ± 14.12 and 74.18 ± 6.01 cm/s. Mean CFR was 1.91 ± 0.51. Myocardial perfusion scintigraphy (MPS) was normal in all the patients. Four patients were lost to follow-up and remaining children did not develop any adverse events in the follow-up period of 64.5 ± 7.19 months. Adenosine stress echocardiography is feasible as the initial screening test in the assessment of asymptomatic post-operative children with ASO, at minimal to no inconvenience to the patient. The findings concurred with stress MPS.


Assuntos
Adenosina/administração & dosagem , Transposição das Grandes Artérias/métodos , Ecocardiografia sob Estresse/métodos , Imagem de Perfusão do Miocárdio/métodos , Tecnécio Tc 99m Sestamibi/administração & dosagem , Transposição dos Grandes Vasos/cirurgia , Criança , Pré-Escolar , Vasos Coronários/diagnóstico por imagem , Estudos de Viabilidade , Feminino , Coração/diagnóstico por imagem , Humanos , Masculino , Volume Sistólico , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Função Ventricular Esquerda
10.
J Family Med Prim Care ; 9(3): 1617-1619, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32509661

RESUMO

AIM: The present study was conducted to determine the prevalence rate of dental implants failure and risk factors affecting dental implant outcome. MATERIALS AND METHODS: The present retrospective study was conducted on 826 patients who received 1420 dental implants in both genders. Length of implant, diameter of implant, location of implant, and bone quality were recorded. Risk factors such as habit of smoking, history of diabetes, hypertension, etc., were recorded. RESULTS: In 516 males, 832 dental implants and in 310 females, 588 dental implants were placed. Maximum dental implant failure was seen with length <10 mm (16%), with diameter <3.75 mm, and with type IV bone (20.6%). The difference found to be significant (P < 0.05). Maximum dental implant failures were seen with smoking (37%) followed by hypertension (20.8%), diabetes (20.3%), and CVDs (18.7%). Healthy patients had the lowest failure rate (4.37%). CONCLUSION: Dental implant failure was high in type IV bone, dental implant with <3.75 mm diameter, dental implant with length <10.0 mm, and among smokers.

11.
Chem Biol Interact ; 315: 108898, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31715134

RESUMO

Usnic acid, a dibenzofuran derivative found in many lichen species, is reported to have anticancer activity against human gastric cancer. We investigated the molecular alterations associated with anticancer effects of usnic acid against human gastric adenocarcinoma AGS and gastric carcinoma SNU-1 cells. Usnic acid (10-25 µM) treatment to these cells caused a significant increase in mitochondrial membrane depolarization and apoptotic cells. Apoptosis induction was accompanied by an increase in the ratio of Bax:Bcl-2 expression and cleaved-PARP. Usnic acid increased the comet tail length and tail DNA in alkaline comet assay indicating DNA double-strand breaks which was also evidenced by an increase in γH2A.X (Ser139) phosphorylation. The expression of DNA damage response proteins including DNA-PKcs, pATM (Ser1981), Chk-2 and p53 were increased. Further, N-acetyl cysteine, a known reactive oxygen species (ROS) scavenger, reversed the effects of usnic acid on expression of DNA damage response proteins and γH2A.X (Ser139) phosphorylation. This reversal was also observed in comet assay in a time and dose-dependent manner suggesting that usnic acid-induced DNA damage was caused by ROS. In addition, the non-toxic concentrations (1-10 µM) of usnic acid inhibited colony forming potential of AGS cells indicating its anti-proliferation activity. More importantly, the concentration of usnic acid that caused significant death in gastric cancer cells, did not show any considerable toxicity to normal human embryonic kidney HEK293 cells, human keratinocyte HaCaT cells and mouse primary gastric cells. Collectively, these results for the first time demonstrated the selective apoptotic effect of usnic acid (10-25 µM) through ROS generation and DNA damage on human gastric cancer cells accompanied with upregulation of γH2A.X (Ser139) phosphorylation, DNA-PKcs and p53.


Assuntos
Apoptose/efeitos dos fármacos , Benzofuranos/farmacologia , Dano ao DNA/efeitos dos fármacos , Proteína Quinase Ativada por DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Histonas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Animais , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Neoplasias Gástricas/metabolismo , Regulação para Cima/efeitos dos fármacos
12.
JCI Insight ; 5(1)2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31821176

RESUMO

Small molecule inhibitors of dual specificity, tyrosine phosphorylation-regulated kinase 1A (DYRK1A), including harmine and others, are able to drive human ß cell regeneration. While DYRK1A is certainly a target of this class, whether it is the only or the most important target is uncertain. Here, we employ a combined pharmacologic and genetic approach to refine the potential mitogenic targets of the DYRK1A inhibitor family in human islets. A combination of human ß cell RNA sequencing, DYRK1A inhibitor kinome screens, pharmacologic inhibitors, and targeted silencing of candidate genes confirms that DYRK1A is a central target. Surprisingly, however, DYRK1B also proves to be an important target: silencing DYRK1A results in an increase in DYRK1B. Simultaneous silencing of both DYRK1A and DYRK1B yields greater ß cell proliferation than silencing either individually. Importantly, other potential kinases, such as the CLK and the GSK3 families, are excluded as important harmine targets. Finally, we describe adenoviruses that are able to silence up to 7 targets simultaneously. Collectively, we report that inhibition of both DYRK1A and DYRK1B is required for induction of maximal rates of human ß cell proliferation, and we provide clarity for future efforts in structure-based drug design for human ß cell regenerative drugs.


Assuntos
Células Secretoras de Insulina/metabolismo , Mitógenos/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Proteínas Tirosina Quinases/efeitos dos fármacos , Adolescente , Adulto , Idoso , Proliferação de Células/efeitos dos fármacos , Feminino , Expressão Gênica , Quinase 3 da Glicogênio Sintase/genética , Quinase 3 da Glicogênio Sintase/metabolismo , Harmina/metabolismo , Harmina/farmacologia , Humanos , Insulinoma , Masculino , Pessoa de Meia-Idade , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Adulto Jovem , Quinases Dyrk
13.
Mitochondrion ; 48: 1-10, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-29902665

RESUMO

Mancozeb (Manganese ethylene bis-dithiocarbamate with zinc salt) is a dithiocarbamate fungicide used to control fungal disease in many fruit plants, flowers and the maintenance of field crops. The effect of mancozeb on cell viability of human gastric adenocarcinoma AGS, SNU-1 cells and human normal FHs 74 Int cells were investigated. This study demonstrated that mancozeb was able to inhibit cell proliferation by 56-82% at 5-10 µM concentrations after 48 h. Mancozeb treatment for 48 h resulted in 33% (P < 0.05) and 61% (P < 0.001) increase in apoptotic cells at 5 and 10 µM concentrations in AGS cells, respectively. Treatment with mancozeb did not cause cell cycle arrest, while modulated the expression level of cleaved caspase-3, and cleavage of poly-(ADP-ribose) polymerase. Furthermore, treatment with mancozeb caused a rapid stimulation of reactive oxygen species (ROS) and loss of mitochondrial transmembrane potential. The results also showed that mancozeb-induced apoptosis was accompanied by up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL. Overall, our data suggested that mancozeb caused ROS generation which induced significant (P < 0.05) apoptosis in AGS cells that was attenuated with pretreatment of NAC. More importantly, same concentration of mancozeb did not show any considerable effect on cell growth, death, cell cycle arrest and ROS generation in normal FHs 74 Int cells. Overall, for the first time these results suggest that mancozeb has selective anticancer activity at lower concentrations against gastric cancer cells.


Assuntos
Apoptose/efeitos dos fármacos , Maneb/farmacologia , Mitocôndrias/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Zineb/farmacologia , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Neoplasias Gástricas/metabolismo , Regulação para Cima/efeitos dos fármacos , Proteína bcl-X/metabolismo
14.
Environ Toxicol Pharmacol ; 63: 103-114, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30199797

RESUMO

Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics.


Assuntos
Dano ao DNA , Estresse Oxidativo , Praguicidas/intoxicação , Doença de Alzheimer/induzido quimicamente , Doença de Alzheimer/genética , Doença de Alzheimer/mortalidade , Epigênese Genética/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Doenças dos Genitais Femininos/induzido quimicamente , Doenças dos Genitais Femininos/genética , Doenças dos Genitais Femininos/mortalidade , Doenças dos Genitais Masculinos/induzido quimicamente , Doenças dos Genitais Masculinos/genética , Doenças dos Genitais Masculinos/mortalidade , Humanos , Masculino , Neoplasias/induzido quimicamente , Neoplasias/genética , Neoplasias/mortalidade , Doença de Parkinson/etiologia , Doença de Parkinson/genética , Doença de Parkinson/mortalidade , Doenças Respiratórias/induzido quimicamente , Doenças Respiratórias/genética , Doenças Respiratórias/mortalidade
15.
Eur J Med Chem ; 157: 1005-1016, 2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30170319

RESUMO

The Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase 1A (DYRK1A) is an enzyme that has been implicated as an important drug target in various therapeutic areas, including neurological disorders (Down syndrome, Alzheimer's disease), oncology, and diabetes (pancreatic ß-cell expansion). Current small molecule DYRK1A inhibitors are ATP-competitive inhibitors that bind to the kinase in an active conformation. As a result, these inhibitors are promiscuous, resulting in pharmacological side effects that limit their therapeutic applications. None are in clinical trials at this time. In order to identify a new DYRK1A inhibitor scaffold, we constructed a homology model of DYRK1A in an inactive, DFG-out conformation. Virtual screening of 2.2 million lead-like compounds from the ZINC database, followed by in vitro testing of selected 68 compounds revealed 8 hits representing 5 different chemical classes. We chose to focus on one of the hits from the computational screen, thiadiazine 1 which was found to inhibit DYRK1A with IC50 of 9.41 µM (Kd = 7.3 µM). Optimization of the hit compound 1, using structure-activity relationship (SAR) analysis and in vitro testing led to the identification of potent thiadiazine analogs with significantly improved binding as compared to the initial hit (Kd = 71-185 nM). Compound 3-5 induced human ß-cell proliferation at 5 µM while showing selectivity for DYRK1A over DYRK1B and DYRK2 at 10 µM. This newly developed DYRK1A inhibitor scaffold with unique kinase selectivity profiles has potential to be further optimized as novel therapeutics for diabetes.


Assuntos
Células Secretoras de Insulina/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Tiadiazinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Relação Estrutura-Atividade , Tiadiazinas/síntese química , Tiadiazinas/química , Quinases Dyrk
16.
J Med Chem ; 61(17): 7687-7699, 2018 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-30059217

RESUMO

DYRK1A has been implicated as an important drug target in various therapeutic areas, including neurological disorders and oncology. DYRK1A has more recently been shown to be involved in pathways regulating human ß-cell proliferation, thus making it a potential therapeutic target for both Type 1 and Type 2 diabetes. Our group, using a high-throughput phenotypic screen, identified harmine that is able to induce ß-cell proliferation both in vitro and in vivo. Since harmine has suboptimal kinase selectivity, we sought to expand structure-activity relationships for harmine's DYRK1A activity, to enhance selectivity, while retaining human ß-cell proliferation capability. We carried out the optimization of the 1-position of harmine and synthesized 15 harmine analogues. Six compounds showed excellent DYRK1A inhibition with IC50 in the range of 49.5-264 nM. Two compounds, 2-2 and 2-8, exhibited excellent human ß-cell proliferation at doses of 3-30 µM, and compound 2-2 showed improved kinase selectivity as compared to harmine.


Assuntos
Harmina/química , Células Secretoras de Insulina/efeitos dos fármacos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Animais , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Fatores de Transcrição NFATC/genética , Fatores de Transcrição NFATC/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Ratos , Relação Estrutura-Atividade , Quinases Dyrk
17.
ACS Chem Biol ; 12(11): 2788-2803, 2017 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-28945333

RESUMO

A lack of target specificity has greatly hindered the success of inhibitor development against matrix metalloproteinases (MMPs) for the treatment of various cancers. The MMP catalytic domains are highly conserved, whereas the hemopexin-like domains of MMPs are unique to each family member. The hemopexin-like domain of MMP-9 enhances cancer cell migration through self-interaction and heterointeractions with cell surface proteins including CD44 and α4ß1 integrin. These interactions activate EGFR-MAP kinase dependent signaling that leads to cell migration. In this work, we generated a library of compounds, based on hit molecule N-[4-(difluoromethoxy)phenyl]-2-[(4-oxo-6-propyl-1H-pyrimidin-2-yl)sulfanyl]-acetamide, that target the hemopexin-like domain of MMP-9. We identify N-(4-fluorophenyl)-4-(4-oxo-3,4,5,6,7,8-hexahydroquinazolin-2-ylthio)butanamide, 3c, as a potent lead (Kd = 320 nM) that is specific for binding to the proMMP-9 hemopexin-like domain. We demonstrate that 3c disruption of MMP-9 homodimerization prevents association of proMMP-9 with both α4ß1 integrin and CD44 and results in the dissociation of EGFR. This disruption results in decreased phosphorylation of Src and its downstream target proteins focal adhesion kinase (FAK) and paxillin (PAX), which are implicated in promoting tumor cell growth, migration, and invasion. Using a chicken chorioallantoic membrane in vivo assay, we demonstrate that 500 nM 3c blocks cancer cell invasion of the basement membrane and reduces angiogenesis. In conclusion, we present a mechanism of action for 3c whereby targeting the hemopexin domain results in decreased cancer cell migration through simultaneous disruption of α4ß1 integrin and EGFR signaling pathways, thereby preventing signaling bypass. Targeting through the hemopexin-like domain is a powerful approach to antimetastatic drug development.


Assuntos
Precursores Enzimáticos/antagonistas & inibidores , Precursores Enzimáticos/metabolismo , Adesões Focais/efeitos dos fármacos , Metaloproteinase 9 da Matriz/metabolismo , Inibidores de Metaloproteinases de Matriz/química , Inibidores de Metaloproteinases de Matriz/farmacologia , Domínios Proteicos/efeitos dos fármacos , Animais , Células COS , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Galinhas , Chlorocebus aethiops , Precursores Enzimáticos/química , Adesões Focais/metabolismo , Hemopexina/química , Humanos , Receptores de Hialuronatos/metabolismo , Integrina alfa4beta1/metabolismo , Metaloproteinase 9 da Matriz/química , Modelos Moleculares , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
19.
J Vasc Interv Neurol ; 9(1): 7-11, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27403217

RESUMO

The authors present a unique case of intracranial lipoma in the interpeduncular cistern associated with proximal P1 segment fenestration. This patient is a 20-year-old male with extensive psychiatric history and complaints of recent auditory hallucinations. Cranial magnetic resonance imaging (MRI) (T1, T2, and FLAIR) showed a hyperintense lesion in the left aspect of interpeduncular cistern with a prominent flow void within the hyperintense lesion suggestive of a combined vascular-lipomatous lesion. Computed tomography (CT) angiography showed a high-riding large tortuous P1 segment on the left side with proximal fenestration, the ectatic posteromedial limb harboring a fusiform dilated segment. Since there are anecdotal cases of cerebral aneurysms associated with intracranial lipomas, a conventional angiography was done, which confirmed a proximal left P1 fenestration and a fusiform-dilated segment, and no aneurysm. There are few cases of hallucinations associated with a vascular midbrain pathology reported in literature, but hallucinations associated with a combination of lipoma and arterial ectasia have never been reported. This article not only demonstrates the MRI and angiographic appearance of this rare lipomatous lesion but also highlights this unique association and significance of auditory hallucinations as a clinical presentation, akin to peduncular hallucinosis.

20.
BJR Case Rep ; 2(2): 20150322, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-30363681

RESUMO

Metastasis to the pituitary gland/sella turcica is an uncommon complication of thyroid cancer. Treating this condition is a challenge in the setting of pituitary insufficiency due to this lesion, and recombinant human thyroid-stimulating hormone (rhTSH) stimulation becomes critically essential. We present a rare case of an 82-year-old female patient with follicular carcinoma of the thyroid with metastasis to the sella turcica in addition to multiple skeletal and lung metastases. MRI of the brain showed a hypointense suprasellar lesion on T 1 weighted images. The thyroid-stimulating hormone level remained persistently low even 4 weeks after thyroidectomy. A whole-body pertechnetate scan could not localize any abnormal tracer uptake and radioactive iodine uptake was also persistently low. The patient did not have symptoms related to pituitary involvement but TSH and early morning adrenocorticotrophic hormone levels were low. After thorough discussion with the neurosurgeon and radiotherapist, it was decided to start the patient on high-dose radioiodine treatment. Persistently low TSH level was a concern for starting radioiodine therapy. In view of this clinical context, rhTSH stimulation was used to achieve adequate TSH levels prior to radioiodine therapy. Subsequently, the patient was treated with 3.7 GBq (100 mci) of high-dose radioiodine. A post-therapy scan demonstrated radioiodine concentration in the thyroid bed remnant, multiple skeletal lesions and the sellar region. Thus, the use of rhTSH was critical in the management of this patient. It helped in radioiodine treatment by stimulating radioiodine uptake in the remnant and at the metastatic sites.

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