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Dysregulation of Vascular Endothelial Growth Factor (VEGF) and its receptor (VEGFR) contributes to atherosclerosis and cardiovascular disease (CVD), making it a potential target for CVD risk assessment. High throughput screening (HTS) approaches have resulted in large-scale in vitro data, providing mechanistic information that can help assess chemical toxicity and identify molecular-initiating events (MIEs) of adverse outcome pathways (AOPs). AOPs represent a logical sequence of biological responses contributing to toxicity and are valuable tools to inform chemical risk assessments. Here, we used HTS data to formulate an AOP relating VEGF signaling perturbation to atherosclerosis. ToxCast, Tox21, and PubChem data were evaluated to obtain bio-profiles of 4165 compounds active in assays targeting VEGFR. Cheminformatics analysis identified 109 enriched structural fingerprints. Applying a subspace clustering approach based on chemical structure bioactivity yielded 12 primary targets, whose relevance to CVD was confirmed by an AI-assisted literature review. An AOP was hypothesized by coupling mechanistic relationships highlighted by HTS data with literature review findings, linking Serotonin Receptor (HTR), Estrogen Receptor Alpha (ERα), and Vasopressin Receptor (AVPR) targets with VEGFR activity, angiogenic signaling, and atherosclerosis. Several endocrine disrupting chemicals (EDCs), e.g., bisphenols, triclosan, dichlorodiphenyltrichloroethane (DDT), and polychlorinated biphenyls (PCBs), were identified as relevant chemical stressors. Subspace clustering of these chemicals evaluated potential MIEs and highlighted associations with use-case classes. By applying computational methods to profile HTS data and hypothesize a mechanistic AOP, this study proposes a data-driven approach to evaluating environmental cardiotoxicity, which could eventually supplement and reduce the need for animal testing in toxicological assessments.
This study explores how disruptions in VEGFR contribute to atherosclerosis, the buildup of plaques in arteries that can lead to CVD. By analyzing data from HTS relevant to CV health, researchers identify how different chemicals affect VEGFR and potentially cause CVD. Using these screening methods, which quickly test many chemicals, the study identifies specific biological changes leading to adverse health outcomes. This research aims to develop methods to assess chemical toxicity without relying on animal testing, making it relevant to human health. The findings link certain chemicals e.g., bisphenols and DDT, changing VEGRF activity and the development of atherosclerosis. An adverse outcome pathway (AOP) framework maps the sequence of biological events from molecular perturbations to disease, providing mechanistic insight and identifying chemicals impacting the AOP targets. This approach helps understand the risks posed by environmental chemicals and protects public health while reducing animal experiments.
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DNA topoisomerase 1 (Topo 1) is a pivotal player in various DNA processes, including replication, repair, and transcription. It serves as a target for anticancer drugs like camptothecin and its derivatives (Topotecan and SN-38/Irinotecan). However, the emergence of drug resistance and the associated adverse effects, such as alopecia, anemia, dyspnea, fever, chills, and painful or difficult urination, pose significant challenges in Topo 1-targeted therapy, necessitating urgent attention. Human DNA Ligase 1 (hLig I), recognized primarily for its role in DNA replication and repair of DNA breaks, intriguingly exhibits a DNA relaxation activity akin to Topo 1. This raised the hypothesis that hLig I might compensate for Topo 1 inhibition, contributing to resistance against Topo 1 inhibitors. To explore this hypothesis, we assessed the efficacy of hLig I inhibition alone and in combination with Topo 1 in cancer cells. As anticipated, the overexpression of hLig I was observed after Topo 1 inhibition in colorectal cancer cells, affirming our hypothesis. Previously identified as an inhibitor of hLig I's DNA relaxation activity, compound 27 (C 27), when combined with Topotecan, demonstrated a synergistic antiproliferative effect on colorectal cancer cells. Notably, cells with downregulated hLig I (via siRNA, inhibitors, or genetic manipulation) exhibited significantly heightened sensitivity to Topotecan. This observation strongly supports the concept that hLig I contribute to resistance against clinically relevant Topo 1 inhibitors in colorectal cancers. In conclusion, our findings offer evidence for the synergistic impact of combining hLig I inhibitors with Topotecan in the treatment of colorectal cancers, providing a promising strategy to overcome resistance to Topo 1 inhibitors.Communicated by Ramaswamy H. Sarma.
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Chemical inhibition of the human ether-a -go-go-related gene (hERG) potassium channel leads to a prolonged QT interval that can contribute to severe cardiotoxicity. The adverse effects of hERG inhibition are one of the principal causes of drug attrition in clinical and pre-clinical development. Preliminary studies have demonstrated that a wide range of environmental chemicals and toxicants may also inhibit the hERG channel and contribute to the pathophysiology of cardiovascular (CV) diseases. As part of the US federal Tox21 program, the National Center for Advancing Translational Science (NCATS) applied a quantitative high throughput screening (qHTS) approach to screen the Tox21 library of 10,000 compounds (~7871 unique chemicals) at 14 concentrations in triplicate to identify chemicals perturbing hERG activity in the U2OS cell line thallium flux assay platform. The qHTS cell-based thallium influx assay provided a robust and reliable dataset to evaluate the ability of thousands of drugs and environmental chemicals to inhibit hERG channel protein, and the use of chemical structure-based clustering and chemotype enrichment analysis facilitated the identification of molecular features that are likely responsible for the observed hERG activity. We employed several machine-learning approaches to develop QSAR prediction models for the assessment of hERG liabilities for drug-like and environmental chemicals. The training set was compiled by integrating hERG bioactivity data from the ChEMBL database with the Tox21 qHTS thallium flux assay data. The best results were obtained with the random forest method (~92.6% balanced accuracy). The data and scripts used to generate hERG prediction models are provided in an open-access format as key in vitro and in silico tools that can be applied in a translational toxicology pipeline for drug development and environmental chemical screening.
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Cardiovascular (CV) disease is one of the most prevalent public health concerns, and mounting evidence supports the contribution of environmental chemicals to CV disease burden. In this study, we performed cardiotoxicity profiling for the Tox21 chemical library by focusing on high-throughput screening (HTS) assays whose targets are associated with adverse events related to CV failure modes. Our objective was to develop new hypotheses around environmental chemicals of potential interest for adverse CV outcomes using Tox21/ToxCast HTS data. Molecular and cellular events linked to six failure modes of CV toxicity were cross-referenced with 1399 Tox21/ToxCast assays to identify cardio-relevant bioactivity signatures. The resulting 40 targets, measured in 314 assays, were integrated via a ToxPi visualization tool and ranking system to prioritize 1138 chemicals based upon formal integration across multiple domains of information. Filtering was performed based on cytotoxicity and generalized cell stress endpoints to try and isolate chemicals with effects specific to CV biology, and bioactivity- and structure-based clustering identified subgroups of chemicals preferentially affecting targets such as ion channels and vascular tissue biology. Our approach identified drugs with known cardiotoxic effects, such as estrogenic modulators like clomiphene and raloxifene, anti-arrhythmic drugs like amiodarone and haloperidol, and antipsychotic drugs like chlorpromazine. Several classes of environmental chemicals such as organotins, bisphenol-like chemicals, pesticides, and quaternary ammonium compounds demonstrated strong bioactivity against CV targets; these were compared to existing data in the literature (e.g., from cardiomyocytes, animal data, or human epidemiological studies) and prioritized for further testing.
Assuntos
Doenças Cardiovasculares/induzido quimicamente , Poluentes Ambientais/efeitos adversos , Ensaios de Triagem em Larga Escala , Poluentes Ambientais/química , Humanos , Estrutura MolecularRESUMO
Histone Deacetylases (HDACs) play a significant role in the regulation of gene expression by modifying histones and non-histone substrates. Since they are key regulators in the reversible epigenetic mechanism, they are considered as promising drug targets for the treatment of various cancers. In the present study, we have developed a workflow for identification of HDAC1 inhibitors using a multistage virtual screening approach from Maybridge and Chembridge chemical library. Initially, a support vector machine based classification model was generated, followed by generation of a zinc-binding group (ZBG) based pharmacophore model. The hits screened from these models were further subjected to molecular docking. Finally, a set of twenty-three molecules were selected from Maybridge and Chembridge library. The biological evaluation of these hits revealed that three out of the twenty-three tested compounds are showing HDAC1 inhibition along with the moderate anti-proliferative activity. It was found that the identified inhibitors are exerting chromosomal loss effect in growing yeast cells. Further, to extend the activity spectrum of the identified inhibitors, the optimization guidelines were drawn with the hydration site mapping approach by using in silico tool Watermap.Communicated by Ramaswamy H. Sarma.
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Inibidores de Histona Desacetilases , Simulação de Acoplamento Molecular , Máquina de Vetores de Suporte , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases , Histonas , Simulação de Dinâmica Molecular , Relação Quantitativa Estrutura-Atividade , Bibliotecas de Moléculas PequenasRESUMO
The histone acetyl transferase (HAT) are involved in acetylation of histones that lead to transcription activation in numerous gene regulatory mechanisms. There are very few GCN5 HAT inhibitors reported despite of their role in cancer progression. In this study, we have utilized in-silico virtual screening approaches based on various machine learning algorithm to identify potent inhibitors of GCN5 HAT from commercially available Maybridge library. We have generated predictive chemoinformatics models based on k-Nearest neighbour, naïve Bayesian, Random Forest and Support Vector Machine. Based on statistical parameters, the RF and SVM models have shown comparative performance. Therefore, we performed the virtual screening with these two models and the consensus hits were selected for further evaluation using molecular docking into the active site of GCN-5 HAT. Finally, a set of 10 molecules were selected and subjected to biological evaluation. Subsequently, inhibition of acetylation shown by three out of the ten molecules in the in-vitro experiments validated their utility as potential HAT inhibitors. Furthermore, the selected hits have also shown weak cell growth decrease in MCF-7 cancer cell lines, which suggests that after subsequent structural optimization the identified molecules may further be explored for the development of anti-cancer agents.
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Inibidores de Histona Desacetilases/farmacologia , Aprendizado de Máquina , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Histona Acetiltransferases/química , Histona Acetiltransferases/metabolismo , Inibidores de Histona Desacetilases/química , Humanos , Simulação de Acoplamento Molecular , Relação Quantitativa Estrutura-Atividade , Bibliotecas de Moléculas Pequenas/químicaRESUMO
Sexually transmitted diseases like trichomoniasis along with opportunistic fungal infections like candidiasis are major global health burden in female reproductive health. In this context a novel non-nitroimidazole class of substituted carbamothioic amine-1-carbothioic thioanhydride series was designed, synthesized, evaluated for trichomonacidal and fungicidal activities, and was found to be more active than the standard drug Metronidazole (MTZ). Compounds were trichomonicidal in the MIC ranges of 4.77-294.1 µM and 32.46-735.20 µM against MTZ-susceptible and -resistant strains, respectively. Further, compounds inhibited the growth of at least two out of ten fungal strains tested at MIC of 7.50-240.38 µM. The most active compound (20) of this series was 3.8 and 9.5 fold more active than the MTZ against the two Trichomonas strains tested. Compound 20 also significantly inhibited the sulfhydryl groups present over Trichomonas vaginalis and was found to be more active than the MTZ in vivo. Further, a docking analysis carried out with cysteine proteases supported their thiol inhibiting ability and preliminary pharmacokinetic study has shown good distribution and systemic clearance.
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Anidrases Carbônicas/farmacologia , Desenho de Fármacos , Fungicidas Industriais/farmacologia , Compostos de Sulfidrila/farmacologia , Trichomonas/efeitos dos fármacos , Anidrases Carbônicas/síntese química , Anidrases Carbônicas/química , Relação Dose-Resposta a Droga , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Metronidazol/química , Metronidazol/farmacologia , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Compostos de Sulfidrila/síntese química , Compostos de Sulfidrila/química , Trichomonas/crescimento & desenvolvimentoRESUMO
DNA replication and repair are complex processes accomplished by the concerted action of a network of enzymes and proteins. DNA ligases play a crucial role in these processes by catalyzing the nick joining between DNA strands. As compared to normal cells, elevated levels of human DNA ligase I (hLigI) is reported in some cancers. We studied the inhibition of hLigI mediated DNA nick sealing activity followed by the antiproliferative activity of novel indole-chalcone based benzopyran compounds on cancer cells. One molecule called compound 27 showed a notable preference for inhibition of hLigI as compared to other ligases and showed enhanced cytotoxicity against colon cancer (DLD-1) cells as compared to normal cells. Mechanistic studies showed that compound 27 directly interacts with hLigI in a competitive manner and did not interact with the DNA substrate during ligation. This novel and potent hLigI inhibitor showed significant inhibition of both monolayer culture as well as 3D culture of DLD-1 cells that mimic solid tumor. It also affected the migration of DLD-1 cells indicating the potential anti-metastatic activity. This novel hLigI inhibitor could therefore serve as a promising lead for anticancer drug development.
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Antineoplásicos/farmacologia , Benzopiranos/farmacologia , Chalcona/farmacologia , Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Ligases/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Benzopiranos/síntese química , Benzopiranos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Chalcona/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Indóis/química , Ligases/metabolismo , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Existing cancer therapies are often associated with drug resistance and toxicity, which results in poor prognosis and recurrence of cancer. This necessitates the identification and development of novel therapeutics against existing as well as novel cellular targets. In this study, a novel class of Benzocoumarin-Stilbene hybrid molecules were synthesized and evaluated for their antiproliferative activity against various cancer cell lines followed by in vivo antitumor activity in a mouse model of cancer. The most promising molecule among the series, i.e. compound (E)-4-(3,5-dimethoxystyryl)-2H-benzo[h]chromen-2-one (19) showed maximum antiproliferative activity in breast cancer cell lines (MDA-MB-231 and 4T1) and decreased the tumor size in the in-vivo 4T1 cell-induced orthotopic syngeneic mouse breast cancer model. The mechanistic studies of compound 19 by various biochemical, cell biology and biophysical approaches suggest that the compound binds to and inhibits the human DNA ligase I enzyme activity that might be the cause for significant reduction in tumor growth and may constitute a promising next-generation therapy against breast cancers.
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Antracenos , Antineoplásicos/química , Antineoplásicos/farmacologia , DNA Ligase Dependente de ATP/antagonistas & inibidores , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estilbenos , Animais , Antracenos/química , Apoptose/efeitos dos fármacos , Neoplasias da Mama , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Estrutura Molecular , Transdução de Sinais/efeitos dos fármacos , Estilbenos/química , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
DNA methylation is an epigenetic change that results in the addition of a methyl group at the carbon-5 position of cytosine residues. DNA methyltransferase (DNMT) inhibitors can suppress tumour growth and have significant therapeutic value. However, the established inhibitors are limited in their application due to their substantial cytotoxicity. Additionally, the standard drugs for DNMT inhibition are non-selective cytosine analogues with considerable cytotoxic side-effects. In the present study, we have designed a workflow by integrating various ligand-based and structure-based approaches to discover new agents active against DNMT1. We have derived a pharmacophore model with the help of available DNMT1 inhibitors. Utilising this model, we performed the virtual screening of Maybridge chemical library and the identified hits were then subsequently filtered based on the Naïve Bayesian classification model. The molecules that have returned from this classification model were subjected to ensemble based docking. We have selected 10 molecules for the biological assay by inspecting the interactions portrayed by these molecules. Three out of the ten tested compounds have shown DNMT1 inhibitory activity. These compounds were also found to demonstrate potential inhibition of cellular proliferation in human breast cancer MDA-MB-231 cells. In the present study, we have utilized a multi-step virtual screening protocol to identify inhibitors of DNMT1, which offers a starting point to develop more potent DNMT1 inhibitors as anti-cancer agents.
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DNA (Citosina-5-)-Metiltransferase 1/antagonistas & inibidores , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/análise , Inibidores Enzimáticos/farmacologia , Modelos Moleculares , Antineoplásicos/análise , Antineoplásicos/química , Antineoplásicos/farmacologia , Teorema de Bayes , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sistema Livre de Células , DNA (Citosina-5-)-Metiltransferase 1/química , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Inibidores Enzimáticos/química , Células HEK293 , Humanos , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Reprodutibilidade dos Testes , Bibliotecas de Moléculas PequenasRESUMO
Rab proteins form the largest branch of the Ras superfamily. Rab proteins are key regulators of intracellular vesicular transport and membrane trafficking. Although RabGTPases are well-recognized targets in human diseases but are under-explored therapeutically in the Leishmania parasite. Using a quantitative cytofluorimetric assay, we analyzed the composition and organization of Rab6GTPase protein which was found to be primarily localized on the parasite subpellicular membrane and flagellum due to its association with kinesin motor proteins in the cytoskeletal microtubules. Our aim was to also assess the diagnostic role of recombinant Rab6 protein from Leishmania donovani (rLdRab6) using sera/plasma of Indian visceral leishmaniasis (VL) patients. Receiver-operating characteristic (ROC) curve analysis indicated 100% sensitivity and 100% specificity for rLdRab6-based ELISA which was almost similar in comparison to recombinant K39-based ELISA (95.83% sensitivity and 100% specificity). Sera of patients from another intracellular pathogenic infection, Mycobacterium tuberculosis, did not contain any significant levels of anti-rLdRab6 antibody. Thus rLdRab6 accuracy in visceral leishmaniasis diagnosis makes it a promising antigen for clinical use.
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Soros Imunes/imunologia , Leishmania donovani/imunologia , Leishmaniose Visceral/imunologia , Proteínas Recombinantes/imunologia , Proteínas rab de Ligação ao GTP/imunologia , Sequência de Aminoácidos , Western Blotting , Dicroísmo Circular , Clonagem Molecular , Epitopos/química , Epitopos/imunologia , Feminino , Humanos , Leishmania donovani/enzimologia , Leishmania donovani/genética , Leishmaniose Visceral/sangue , Masculino , Microscopia de Fluorescência , Dobramento de Proteína , Estrutura Secundária de Proteína , Curva ROC , Proteínas Recombinantes/análise , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Sensibilidade e Especificidade , Proteínas rab de Ligação ao GTP/análise , Proteínas rab de Ligação ao GTP/química , Proteínas rab de Ligação ao GTP/genéticaRESUMO
Trichomoniasis and candidiasis are amongst the most common morbidity-causing reproductive tract infections, generally treated by Metronidazole and Fluconazole respectively. Poor vaginal efficacy, drug-resistance and non-spermicidal nature limit their use as topical microbicidal contraceptives. Bis(dialkylaminethiocarbonyl)disulfides (4-38) were designed as dually active, non-surfactant molecules capable of eliminating Trichomonas vaginalis and Candida strains as well as irreversibly immobilizing 100% human sperm instantly, at doses non-cytotoxic to human cervical epithelial cells and vaginal microflora in vitro. Compounds 12, 16, 17 were fifty times more active than nonoxynol-9, OTC vaginal spermicide, and compounds 12 and 17 have shown remarkable in vivo activity in rabbit model. Most promising compound 17 has shown promise for further development as a double-edged vaginal microbicide due to their improved activity and safety along with notable in vivo trichomonicidal activity. Role of disulfide group was established by loss of spermicidal activity on chemical modifications (39-56). These disulfides might be targeting thiol groups present over cell membrane of human sperm and Trichomonas as shown by fluorescence labeling of free thiols.
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Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Dissulfetos/química , Espermicidas , Animais , Anti-Infecciosos/química , Candida/efeitos dos fármacos , Masculino , Camundongos , Coelhos , Espermatozoides/efeitos dos fármacos , Trichomonas vaginalis/efeitos dos fármacosRESUMO
Aberrant epigenetic control is a common phenomenon in tumour progression. The epigenetic modifications such as DNA methylation, histone modification and nucleosome remodelling are involved in the regulation of many biological processes, alteration in which can result into tumourogenesis. Histone acetylation is often associated with gene expression; however deacetylated histones generally results in gene suppression. This whole reversible process is mediated by Histone acetyltranferase and Histone deacetylases (HDACs) respectively. HDACs perform the deacetylation of histones in nucleosomes, which intervenes changes in chromatin remodelling, prompting regulation of gene expression. HDACs likewise direct the acetylation status of various other non-histone substrates that includes oncogenes and tumour silencing proteins. As HDAC inhibition induces various tumour cells to enter apoptosis and consequently cell cycle arrest therefore, a large number of HDAC inhibitors have been reported to develop as a new class of anti-cancer agents. Apart from the two existing FDA approved HDAC inhibitors- Varinostat and Depsipetide, recently a new drug Farydak has been approved by the FDA for the treatment of multiple myeloma which thus validated the use of HDAC inhibitors for the treatment of cancer. Also, several other HDAC inhibitors are undergoing clinical trials. Here, we have reviewed the current status of structure based computational studies that has helped to rationalize the successful identification of HDAC inhibitors. The objective of the present review is to provide an overview of contribution of structure-based computational studies that have helped in identifying HDAC inhibitors with an emphasis on the perspectives of its insight, current status, advances and future opportunities as well as the evolving efforts to characterize the structural dynamics of HDACs.
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Desenho Assistido por Computador , Desenho de Fármacos , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Humanos , Modelos Moleculares , Estrutura MolecularRESUMO
BACKGROUND: Leptomonas is monogenetic kinetoplastid parasite of insects and is primitive in comparison to Leishmania. Comparative studies of these two kinetoplastid may share light on the evolutionary transition to dixenous parasitism in Leishmania. In order to adapt and survive within two hosts, Leishmania species must have acquired virulence factors in addition to mechanisms that mediate susceptibility/resistance to infection in the pathology associated with disease. Rab proteins are key mediators of vesicle transport and contribute greatly to the evolution of complexity of membrane transport system. In this study we used our whole genome sequence data of these two divergent kinetoplastids to analyze the orthologues/paralogues of Rab proteins. RESULTS: During change of lifestyle from monogenetic (Leptomonas) to digenetic (Leishmania), we found that the prenyl machinery remained unchanged. Geranylgeranyl transferase-I (GGTase-I) was absent in both Leishmania and its sister Leptomonas. Farnesyltransferase (FTase) and geranylgeranyl transferase-II (GGTase-II) were identified for protein prenylation. We predict that activity of the missing alpha-subunit (α-subunit) of GGTase-II in Leptomonas was probably contributed by the α-subunit of FTase, while beta-subunit (ß-subunit) of GGTase-II was conserved and indicated functional conservation in the evolution of these two kinetoplastids. Therefore the ß-subunit emerges as an excellent target for compounds inhibiting parasite activity in clinical cases of co-infections. We also confirmed that during the evolution to digenetic life style in Leishmania, the parasite acquired capabilities to evade drug action and maintain parasite virulence in the host with the incorporation of short-chain dehydrogenase/reductase (SDR/MDR) superfamily in Rab genes. CONCLUSION: Our study based on whole genome sequences is the first to build comparative evolutionary analysis and identification of prenylation proteins in Leishmania and its sister Leptomonas. The information presented in our present work has importance for drug design targeted to kill L. donovani in humans but not affect the human form of the prenylation enzymes.
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Kinetoplastida/genética , Leishmania/genética , Prenilação de Proteína , Alquil e Aril Transferases/metabolismo , Animais , Evolução Biológica , Genoma de Protozoário , Humanos , Insetos/parasitologia , Kinetoplastida/citologia , Kinetoplastida/enzimologia , Kinetoplastida/metabolismo , Leishmania/citologia , Leishmania/enzimologia , Leishmania/metabolismo , Leishmaniose/parasitologia , Redes e Vias MetabólicasRESUMO
Recent advances indicate a possible role of phytochemicals as modulatory factors in signaling pathways. We have previously demonstrated PHLPP2-mediated suppression of Nrf2 responses during oxidant attack. The present study was designed to explore Nrf2-potentiating mechanism of morin, a flavonol, via its possible role in intervening PHLPP2-regulated Akt/GSK3ß/Fyn kinase axis. Efficacy of morin was evaluated against oxidative stress-mediated damage to primary hepatocytes by tert-butyl hydroperoxide (tBHP) and acetaminophen. The anti-cytotoxic effects of morin were found to be a consequence of fortification of Nrf2-regulated antioxidant defenses since morin failed to sustain activities of redox enzyme in Nrf2 silenced hepatocytes. Morin promoted Nrf2 stability and its nuclear retention by possibly modulating PHLPP2 activity which subdues cellular Nrf2 responses by activating Fyn kinase. Pull-down assay using morin-conjugated beads indicated the binding affinity of morin towards PHLPP2. Molecular docking also revealed the propensity of morin to occupy the active site of PHLPP2 enzyme. Thus, dietary phytochemical morin was observed to counteract oxidant-induced hepatocellular damage by promoting Nrf2-regulated transcriptional induction. The findings support the novel role of morin in potentiating Nrf2 responses by limiting PHLPP2 and hence Fyn kinase activation. Therefore, morin may be exploited in developing novel therapeutic strategy aimed at enhancing Nrf2 responses.
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Flavonoides/farmacologia , Hepatócitos/metabolismo , Fator 2 Relacionado a NF-E2/fisiologia , Estresse Oxidativo , Fosfoproteínas Fosfatases/metabolismo , Acetaminofen/toxicidade , Analgésicos não Narcóticos/toxicidade , Animais , Domínio Catalítico , Células Cultivadas , Citoproteção , Avaliação Pré-Clínica de Medicamentos , Flavonoides/química , Hepatócitos/efeitos dos fármacos , Masculino , Potencial da Membrana Mitocondrial , Simulação de Acoplamento Molecular , Fosfoproteínas Fosfatases/química , Cultura Primária de Células , Ligação Proteica , Estabilidade Proteica , Ratos Wistar , Ativação TranscricionalRESUMO
The growing population and health-care burden (due to STIs and HIV) imposes a particular economic crisis over resource-poor countries. Thus a novel approach as vaginal microbicides emerges as integrated tool to control both population and anti-STIs/HIV. Our continued efforts in this field led to the synthesis of fifteen N-alkyl/aryl-4-(3-substituted-3-phenylpropyl) piperazine-1-carbothioamide (12-26) derivatives as topical vaginal microbicides which were evaluated for anti-Trichomonas, spermicidal, antifungal and reverse transcriptase (RT) inhibitory activities. All compounds were also tested for preliminary safety through cytotoxicity assays against human cervical cell line (HeLa) and the vaginal flora, Lactobacillus. Docking studies were performed to gain an insight into the binding mode and interactions of the most promising compound 12 [oxo derivative], comprising of reverse transcriptase (RT) inhibitory (72.30%), spermicidal (MEC 0.01%), anti-Trichomonas (MIC 46.72 µM) and antifungal (MIC 9.34-74.8 µM) activities, along with its hydroxyl (17) and O-alkylated 4-trifluoromethylphenoxy (22) derivative, with similar activities. The stability of compound 12 in simulated vaginal fluid (SVF) and its preliminary in vivo pharmacokinetics performed in female NZ-rabbits signifies its clinical safety in comparison to marketed spermicide Nonoxynol-9.
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Antibacterianos/farmacologia , Antifúngicos/farmacologia , Piperazinas/farmacologia , DNA Polimerase Dirigida por RNA/metabolismo , Inibidores da Transcriptase Reversa/farmacologia , Espermicidas/farmacologia , Tioamidas/farmacologia , Vagina/efeitos dos fármacos , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Relação Dose-Resposta a Droga , Feminino , Células HeLa , Humanos , Lactobacillus acidophilus/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Testes de Sensibilidade Parasitária , Piperazinas/síntese química , Piperazinas/química , Coelhos , Inibidores da Transcriptase Reversa/síntese química , Inibidores da Transcriptase Reversa/química , Espermicidas/síntese química , Espermicidas/química , Espermatozoides/efeitos dos fármacos , Relação Estrutura-Atividade , Tioamidas/síntese química , Tioamidas/química , Trichomonas vaginalis/efeitos dos fármacosRESUMO
Human DNA ligase1 (hLig1) is the major replicative enzyme in proliferating mammalian cells that join Okazaki fragments of the lagging strand during DNA replication. Interruptions in the process of ligation cause DNA damage to accumulate, resulting in cytotoxicity and cell death. In the present study we demonstrate that pyrrolo[1,4] benzodiazepine (PBD) derivatives exhibit anticancer properties by targeting the nick sealing activity of hLig1 as opposed to the DNA interaction activity known for such compounds. Our in silico and in vitro assays demonstrate the binding of these molecules with amino acid residues present in the DNA binding domain (DBD) of the hLig1 enzyme. Two of these hLig1 inhibitors S010-015 and S010-018 demonstrated selective cytotoxicity against DLD-1 (colon cancer) and HepG2 (hepatic cancer) cells in a dose dependant manner. The molecules also reduced cell viability and colony formation at concentrations of ⩽20µM in DLD-1 and HepG2 cells and induced apoptotic cell death. In yet another significant finding, the molecules reduced the migration of cancer cells in wound healing experiments, indicating their anti-metastatic property. In summary, we report the anticancer activity of PBD derivatives against DLD-1 and HepG2 cells and propose a new molecular target for their activity.
Assuntos
Antineoplásicos/farmacologia , Benzodiazepinonas/farmacologia , DNA Ligases/metabolismo , Apoptose/efeitos dos fármacos , Sequência de Bases , Linhagem Celular , DNA/efeitos dos fármacos , DNA Ligase Dependente de ATP , Primers do DNA , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Técnicas In Vitro , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Espectrometria de Fluorescência , Cicatrização/efeitos dos fármacosRESUMO
Prophylactic prevention is considered as the most promising strategy to tackle STI/HIV. Twenty-five dithiocarbamate-thiourea hybrids (14-38) were synthesized as woman controlled topical vaginal microbicides to counter Trichomonas vaginalis and sperm along with RT inhibition potential. The four promising compounds (18, 26, 28 and 33) were tested for safety through cytotoxic assay against human cervical cell line (HeLa) and compatibility with vaginal flora, Lactobacillus. Docking study of most promising vaginal microbicide (33) revealed that it docked in a position and orientation similar to known reverse transcriptase inhibitor Nevirapine. The preliminary in vivo pharmacokinetics of compound 33 was performed in NZ-rabbits to evaluate systemic toxicity in comparison to Nonoxynol-9.
Assuntos
Anti-Infecciosos/farmacologia , Tiocarbamatos/farmacologia , Tioureia/farmacologia , Vagina , Anti-Infecciosos/química , Feminino , HIV/efeitos dos fármacos , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Tiocarbamatos/química , Tioureia/química , Trichomonas vaginalis/efeitos dos fármacosRESUMO
Virtual screening (VS) is a well-established technique, which is now routinely employed in computer aided drug designing process. VS can be broadly classified into two categories, i.e., ligand-based and structure-based approach. In recent years, VS has emerged as a time saving and cost effective technique, capable of screening millions of compounds in a user friendly manner. In the area of cancer drug design, VS methods have been widely used and helped in identifying novel molecules as potential anti-cancer agents. Both ligand-based VS (LBVS) structure-based VS (SBVS) methods have been highly useful in the identification of a number of potential anti-cancer agents exhibiting activities in nanomolar range. In tune with the rapid progress in the enhancement of computational power, VS has witnessed significant change in terms of speed and hit rate and in future it is expected that VS will be a preferential alternative to high throughput screening (HTS). This review, discusses recent trends and contribution of VS in the area of anti-cancer drug discovery.
Assuntos
Antineoplásicos/química , Simulação por Computador , Avaliação Pré-Clínica de Medicamentos/métodos , Desenho de Fármacos , Descoberta de Drogas/métodosRESUMO
Serine hydroxymethyltransferase belongs to the class of pyridoxal-5-phosphate enzymes along with aspartate aminotransferase. To explore the function of residue(s) involved in binding of the carboxylate group of Tetrahydrofolic acid (THF) to L. donovani cytosolic serine hydroxymethyltransferase (LdcSHMT), the gene was cloned in pET-28(a) vector, overexpressed and purified to homogeneity. With the help of docking results of THF to the active site of protein, the key residues involved in interaction were identified. In an attempt to unravel the function of Arg265 residue involved in binding of the carboxylate group of THF, Arg-265 was mutated to Ala by site-directed mutagenesis. The Arg265Ala-LdcSHMT showed increased Km value (threefold) and decreased kcat/Km value (threefold) for H4-folate as compared with wild type enzyme. The wild and mutant enzymes exhibited similar Km and kcat/Km values for L-allo-threonine. Unlike the wild type enzyme, mutant failed to form characteristic quinonoid intermediate and was unable to carry out the exchange of α-proton from glycine in the presence of Tetrahydrofolate. These results suggested that Arg265 residue is required for the binding of Tetrahydrofolate and may be the base that abstracts α-proton from glycine, leading to formation of quinonoid intermediate in cytosolic SHMT of L. donovani.