Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Toxicon ; 239: 107632, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38310691

RESUMO

Snake venoms are known to contain toxins capable of interfering with normal physiological processes of victims. Specificity of toxins from snake venoms give scope to identify new molecules with therapeutic action and/or help to understand different cellular mechanisms. Russell's viper venom (RVV) is a mixture of many bioactive molecules with enzymatic and non-enzymatic proteins. The present article describes Daboialipase (DLP), an enzymatic phospholipase A2 with molecular mass of 14.3 kDa isolated from RVV. DLP was obtained after cation exchange chromatography followed by size-exclusion high performance liquid chromatography (SE-HPLC). The isolated DLP presented strong inhibition of adenosine di-phosphate (ADP) and collagen induced platelet aggregation. It also showed anti-thrombin properties by significantly extending thrombin time in human blood samples. Trypan blue and resazurin cell viability assays confirmed time-dependent cytotoxic and cytostatic activities of DLP on MCF7 breast cancer cells, in vitro. DLP caused morphological changes and nuclear damage in MCF7 cells. However, DLP did not cause cytotoxic effects on non-cancer HaCaT cells. Peptide sequences of DLP obtained by O-HRLCMS analysis showed similarity with a previously reported PLA2 (Uniprot ID: PA2B_DABRR/PDB ID: 1VIP_A). An active Asp at 49th position, calcium ion binding site and anticoagulant activity sites were identified in 1 VIP_A. These findings are expected to contribute to designing new anti-platelet, anticoagulant and anti-cancer molecules.


Assuntos
Anticoagulantes , Fosfolipases A2 , 60568 , Animais , Humanos , Anticoagulantes/química , Anticoagulantes/isolamento & purificação , Anticoagulantes/farmacologia , Fosfolipases A2/química , Fosfolipases A2/isolamento & purificação , Fosfolipases A2/farmacologia , Trombina/antagonistas & inibidores , Venenos de Víboras/química , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia
2.
Eur Neuropsychopharmacol ; 78: 81-92, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37775363

RESUMO

This meta-analysis investigated the efficacy, safety, and tolerability of lamotrigine versus placebo in preventing relapse and recurrence of mood episodes in women of childbearing age with bipolar I disorder. Following up to 16 weeks' open-label lamotrigine treatment, responders were randomized to double-blind treatment, including lamotrigine 100-400 mg/day or placebo, in four trials of up to 76 weeks. Women aged 18-45 years who received ≥ 1 dose of study treatment and had ≥ 1 efficacy assessment in the double-blind phase were pooled for efficacy analysis. The primary outcome was median time to intervention for any mood episode (TIME). Of 717 eligible women in the open-label phase, 287 responded and were randomized to lamotrigine (n = 153) or placebo (n = 134). The randomized group had a mean (SD) of 2.0(2.02) manic and 2.5(2.02) depressive episodes in the 3 years before screening. Median TIME was 323 days with lamotrigine and 127 days with placebo (HR 0.69; 95% CI 0.49, 0.96; p = 0.030). Lamotrigine delayed time to intervention for any depressive episode (HR 0.59; 95% CI 0.39, 0.90; p = 0.014) with no treatment difference for manic episodes (HR 0.91; 95% CI 0.52, 1.58; p = 0.732). 2/717 (< 1%) participants experienced serious rash-related adverse events (AEs) during the open-label phase, and 52/717 (7%) had non-serious rash-related events leading to study withdrawal. Incidence of AEs and AEs leading to withdrawal were similar between lamotrigine and placebo groups. Lamotrigine delayed relapse and recurrence of mood episodes, largely by preventing depressive episodes, and was well tolerated in women of childbearing age.


Assuntos
Transtorno Bipolar , Exantema , Humanos , Feminino , Lamotrigina/efeitos adversos , Transtorno Bipolar/diagnóstico , Triazinas/efeitos adversos , Anticonvulsivantes/uso terapêutico , Mania/induzido quimicamente , Mania/tratamento farmacológico , Método Duplo-Cego , Recidiva , Exantema/induzido quimicamente , Exantema/tratamento farmacológico , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
Toxicon ; 232: 107213, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37419286

RESUMO

Vipegrin is a 6.8 kDa Kunitz-type serine proteinase inhibitor purified from Russell's viper (Vipera russelii russelii) venom. Kunitz-type serine proteinase inhibitors are non-enzymatic proteins and are ubiquitous constituents of viper venoms. Vipegrin could significantly inhibit the catalytic activity of trypsin. It also posseses disintegrin-like properties and could inhibit collagen and ADP-induced platelet aggregation in a dose-dependent manner. Vipegrin is cytotoxic to MCF7 human breast cancer cells and restricts its invasive property. Confocal microscopic analysis revealed that Vipegrin could induce apoptosis in MCF7 cells. Vipegrin disrupts cell to cell adhesion of MCF7 cells through its disintegrin-like activity. It also causes disruption of attachment of MCF7 cells to synthetic (poly L-lysine) and natural (fibronectin, laminin) matrices. Vipegrin did not cause cytotoxicity on non-cancerous HaCaT, human keratinocytes. The observed properties indicate that Vipegrin may help the development of a potent anti-cancer drug in future.


Assuntos
Inibidores de Serino Proteinase , Animais , Humanos , Inibidores de Serino Proteinase/farmacologia , Venenos de Víboras , Desintegrinas , Agregação Plaquetária , /metabolismo
4.
J Phys Chem B ; 127(1): 104-120, 2023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36594702

RESUMO

Elucidation of the photophysical and biochemical properties of small molecules can facilitate their applications as prospective therapeutic imaging (theragnostic) agents. Herein, we demonstrate the luminescence behavior of a strategically designed potential therapeutic thiosemicarbazone derivative, (E)-1-(4-(diethylamino)-2-hydroxybenzylidene)-4,4-dimethylthiosemicarbazide (DAHTS), accompanied by the illustration of its solvation and solvation dynamics using spectroscopic techniques and exploring its promising antitumor activities by adopting the necessary biochemical assays. Solvent-dependent photophysical properties, namely UV-vis absorption, fluorescence emission, and excitation profiles, concentration-dependent studies, and time-resolved fluorescence decays, serve as footprints to explain the existence of DAHTS monomers, its excited-state intramolecular proton transfer (ESIPT) product, and dimeric and aggregated forms. The emission intensity progressively intensifies with increasing polarity and proticity of the solvents up to MeOH, but in water, a sudden dip is seen. Solvent polarity and H-bonding modulate the fluorescence behavior of the primary emission peak and significantly influence the formation of the dimer and DAHTS aggregates. The designed luminophore (DAHTS) exhibits significant antiproliferative activity against the human lung cancer (A549) cell lines with inhibitory concentrations (IC50) of 16.88 and 11.92 µM for 24 and 48 h, respectively. DAHTS effectively reduces the cell viability and induces cytotoxicity with extensive morphological changes in A549 cells in the form of spikes when compared to the normal HEK cell lines. More importantly, it increases the p53 expression at the mRNA level that consolidates its potential therapeutic activity. The effect of DAHTS on apoptotic pathways against the A549 cell line has been investigated to determine its probable mechanism of cell death. Thus, the all-inclusive understanding of the photophysical properties and the necessary biochemical assays put forward important steps toward tailoring the thiosemicarbazone core structure for favorable cancer theragnostic applications in academic and pharmaceutical research.


Assuntos
Neoplasias Pulmonares , Tiossemicarbazonas , Humanos , Tiossemicarbazonas/farmacologia , Solventes/química , Linhagem Celular , Apoptose , Neoplasias Pulmonares/tratamento farmacológico
5.
J Cell Commun Signal ; 17(3): 773-791, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36538275

RESUMO

Colorectal cancer (CRC) is the third most diagnosed cancer in the world. A better understanding of the molecular mechanism of CRC is essential for making novel strategies for the CRC management and its prevention. The present study aims to explore the molecular mechanism through integrated bioinformatics analysis by analyzing genes and their co-expression pattern in normal and CRC states. GSE110223, GSE110224 and GSE113513 gene expression profiles were analyzed in this study. The co-expression networks for normal and tumor samples were constructed separately and analyzed to identify the modules, sub-networks and key genes. Gene regulatory network analysis was done to understand the regulatory mechanism of selected genes. Survival analysis was performed for the identified sub-networks and key genes to understand their role in CRC progression. A total of seven modules were detected and the KEGG pathway analysis revealed these modules were mainly enriched with cell cycle, metabolism and signaling-related pathways. E2F6 and ETV4 transcription factors regulating the activity of multiple genes of identified modules were found to be up-regulated in CRC. Six Sub-networks and seven key genes, BORA, CCT7, DTL, RUVBL1, RUVBL2, THEM6 and TMEM97 associated with the CRC progression were identified. Disease-gene association analysis identified a novel association of the BORA gene with CRC that activates and regulates the AURORA-PLK1 cascades in the cell cycle. Survival analysis indicates that the overexpressed BORA is associated with unfavourable overall survival in CRC. The mechanistic role of BORA in the regulation of cell cycle progression suggests that BORA might act as a potential therapeutic target for CRC.

6.
Toxicon ; 221: 106979, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36423674

RESUMO

Serine Proteinase Associated Disintegrin-1 (SPAD-1) is a low molecular mass (26 kDa) positively charged protein purified from Russell's viper venom (RVV) possessing cytotoxic activity on MCF7, human breast cancer cells. Primary sequence analysis of the protein confirms that it is a novel Snake Venom Serine Proteinase (SVSP) and a member of the trypsin family. SPAD-1 contains a conserved triad of Histidine (H), Aspartic acid(D) and Serine(S) residues at its active site for proteinase activity and also an adjacent histidine-glycine-aspartic acid (HGD) disintegrin-like motif. The serine proteinase and disintegrin parts are functionally active and independent. SPAD-1 showed proteolytic digestion of fibrinogen and fibronectin, but laminin digestion was below the detectable limit. Proteolytically inactivated SPAD-1 inhibited collagen and ADP-induced platelet aggregation. This study proposes considering Serine Proteinase Associated Disintegrin (SPAD) as a new group of snake venom proteins. Members of this group contain a serine proteinase catalytic triad and a disintegrin-like motif. SPAD-1 caused visible morphological changes in MCF7 cells, including a reduction of the cell-to-cell attachments, rounding of cell shape and death, in vitro. SPAD-1 also showed a dose-dependent significant decrease in the invasive potency of breast cancer cells. Confocal microscopic analysis revealed the breakage of nuclei of the SPAD-1-treated cells. SPAD-1 also increased cell detachment from the poly L-lysine-coated, laminin-coated and fibronectin-coated culture plate matrices, confirming the disintegrin activity. This study concludes that SPAD-1 may be a good candidate for anti-tumour drug design in the future.


Assuntos
Neoplasias da Mama , Animais , Humanos , Feminino , Venenos de Víboras/química , Desintegrinas/farmacologia , Fibronectinas , Serina Proteases/farmacologia , Células MCF-7 , Laminina , Histidina , Ácido Aspártico
7.
Toxicon ; 221: 106982, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36435228

RESUMO

Disintegrins are small peptides possessing a tripeptide motif capable of binding to integrins. These were first isolated from viper venoms and are now also found in many other hematophagous organisms. Many integrins have been studied for their role in the onset of disease and the interaction of disintegrins with these receptors makes them potential therapeutic molecules. Disintegrins are also used as molecular scaffolds to design effective drugs for cardiovascular diseases and cancer. Even the gene and protein sequencing data of disintegrins have provided insights into understanding the molecular complexity of disintegrins. In this review, we try to summarize the structural and functional importance of disintegrins in identifying the biological targets and triggering various signaling pathways involved in platelet aggregation and cancer. Also, we have tried to elucidate a possible molecular mechanism behind the action of disintegrins on platelet aggregation and cancer. This understanding will help us to design and to explore more of these integrin-binding molecules.


Assuntos
Desintegrinas , Neoplasias , Humanos , Desintegrinas/química , Agregação Plaquetária , Inibidores da Agregação Plaquetária/química , Venenos de Serpentes/química , Neoplasias/tratamento farmacológico , Integrinas/metabolismo , Venenos de Víboras/química , Proliferação de Células
8.
Biomed Pharmacother ; 139: 111707, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34243615

RESUMO

Invasive ductal carcinoma (IDC) is the most recurrent cancer, accounting for 80% of all breast cancers worldwide. Originating from the milk duct, it eventually invades the fibrous tissue of the breast outside the duct, proliferation takes 1-2 months for each division. Quinacrine (QC), an FDA-approved small molecule, has been shown to have anti-cancer activity in numerous cancerous cell lines through diverse pathways; ultimately leading to cell death. Here, we have investigated the mode of action of QC in MCF7 cells. This study demonstrated the modulation of cellular cytoskeleton, such as the formation of distinct filopodial and lamellipodial structures and spikes, through the regulation of small-GTPases. We also observed that QC induces a signaling cascade by inducing apoptotic cell death by increasing ROS generation and altering HSP70 expression; which presumably involves ERK regulation. Our findings show that QC could be an attractive chemotherapeutic agent having a "shotgun" nature with potential of inducing different signaling pathways leading to apoptotic cell death. This opens new avenues for research on developing QC as an effective therapeutic agent for the treatment of invasive ductal carcinomas.


Assuntos
Carcinoma Ductal/tratamento farmacológico , Carcinoma Ductal/metabolismo , Citocromos c/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Quinacrina/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Células MCF-7 , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
10.
Oncotarget ; 11(18): 1603-1617, 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32405336

RESUMO

BACKGROUND: Quinacrine (QC) is popular for its anti-malarial activity. It has been reported exhibiting anti-cancerous properties by suppressing nuclear factor-κB and activating p53 signaling; however, its effect on cellular pathways in human non-small cell lung cancer (NSCLC) has not been studied. MATERIALS AND METHODS: Binding of QC with GSTA1 was studied computationally as well as through GST activity assay kit. Cell viability, cell cycle and mitochondrial membrane potential activity were studied using flow cytometry. RT-PCR and western blot were carried out to understand the involvement of various genes at their mRNA as well as protein level. RESULTS: QC inhibited the activity of GSTA1 approximately by 40-45% which inhibits cell survival and promotes apoptosis. QC reduced viability of NSCLC cells in a dose-dependent manner. It also causes nuclear fragmentation, G1/S arrest of cell cycle and ROS generation; which along with disruption of mitochondrial membrane potential activity leads to apoptotic fate. CONCLUSIONS: Results revealed, QC has promising anti-cancer potential against NSCLC cells via inhibition of GSTA1, induction of G1/S arrest and ROS mediated apoptotic signaling.

11.
J Biosci ; 452020.
Artigo em Inglês | MEDLINE | ID: mdl-32098922

RESUMO

Quinacrine (QC), an FDA-approved anti-malarial drug, has shown to have anticancer activities. Due to its 'shotgun' nature, QC has become an inevitable candidate for combination chemotherapy. There is lack of study of the molecular interplay between colorectal cancer (CRC) microenvironment and its metastasis. In this study, we focused on the differential anti-cancerous effect of QC on two different human cancer cell lines, HCT 116 and INT 407. Results suggest that cytotoxicity increased in both the cell lines with an increase in QC concentration. The expression patterns of small-GTPases and caspases were altered significantly in QC-treated cells compared to non-treated cells. HSP70 and p53 showed comparable differences in the expression pattern. The wound-healing assay showed an increase in the denuded zone, with an increase in the concentration of QC. The formation of apoptotic nuclei increased with a rise in the concentration of QC in both the cell lines. The decrease and increase in caspase 9 and caspase 3 expression respectively were studied, confirming apoptosis by the extrinsic pathway.


Assuntos
Apoptose/efeitos dos fármacos , Caspases/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Quinacrina/farmacologia , Antineoplásicos/farmacologia , Caspases/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , GTP Fosfo-Hidrolases/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Humanos
12.
Sci Rep ; 9(1): 436, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679528

RESUMO

Type II alveolar cells are highly robust in nature, yet susceptible to aerosolized nanoparticles (NPs). Dysfunction in these specialized cells, can often lead to emphysema, edema, and pulmonary inflammation. Long-time exposure can also lead to dangerous epigenetic modifications and cancer. Among the manufactured nanomaterials, metal oxide nanoparticles are widely encountered owing to their wide range of applications. Scores of published literatures affirm ZnO NPs are more toxic to human alveolar cells than TiO2. However, signalling cascades deducing differences in human alveolar responses to their exposure is not well documented. With A549 cells, we have demonstrated that epithelial to mesenchymal transition and an increased duration of phosphorylation of eIF2α are crucial mechanisms routing better tolerance to TiO2 NP treatment over exposure to ZnO. The increased migratory capacity may help cells escape away from the zone of stress. Further, expression of chaperone such as Hsp70 is also enhanced during the same dose-time investigations. This is the first report of its kind. These novel findings could be successfully developed in the future to design relief strategies to alleviate metal oxide nanoparticle mediated stress.


Assuntos
Transição Epitelial-Mesenquimal/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Óxido de Zinco/toxicidade , Células A549 , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/genética , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Relação Dose-Resposta a Droga , Transição Epitelial-Mesenquimal/genética , Fator de Iniciação 2 em Eucariotos/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/genética , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fosforilação/efeitos dos fármacos
13.
J Phys Chem B ; 122(14): 3680-3695, 2018 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-29561610

RESUMO

In the development of small-molecule drug candidates, naphthalimide-based compounds hold a very important position as potent anticancer agents with considerable safety in drug discoveries. Being synthetically and readily accessible, naphthalimide compounds with planar architecture have been developed mostly as DNA-targeting intercalators. However, in this article, it is demonstrated, for the first time, that an unfused naphthalimide-benzothiazole bichromophoric compound 2-(6-chlorobenzo[ d] thiazol-2-yl)-1 H-benzo[ de] isoquinoline-1,3(2 H)-dione (CBIQD), seems to expand the bioactivity of naphthalimide as anti-mitotic agent also. Preliminary studies demonstrate that CBIQD interferes with human lung cancer (A549) cell proliferation and growth and causes cellular morphological changes. However, the underlying mechanism of its antitumor action and primary cellular target in A549 cells remained skeptical. Confocal microscopy in A549 cells revealed disruption of interphase microtubule (MT) network and formation of aberrant multipolar spindle. Consistent with microscopy results, UV-vis, steady-state fluorescence, and time-resolved fluorescence (TRF) studies demonstrate that CBIQD efficiently binds to tubulin ( Kb = 2.03 × 105 M-1 ± 1.88%), inhibits its polymerization, and depolymerizes preformed microtubules (MTs). Low doses of CBIQD have also shown specificity toward tubulin protein in the presence of a nonspecific protein like bovine serum albumin as well as other cytoskeleton component, actin. The in vitro determination of binding site coupled with in silico studies suggests that CBIQD may prefer to occupy the colchicine binding site. Further, CBIQD perturbed tubulin conformation to some extent and protected ∼1.4 cysteine residues toward chemical modification by 5,5'-dithiobis-2-nitrobenzoic acid. We also suggest the possible mechanism underlying CBIQD-induced cancer cell cytotoxicity: CBIQD, when bound to tubulin, may prevent it to maintain a straight conformation; consequently, the α- and ß-heterodimers might be no longer available for MT growth. Thus, the consolidated spectroscopic research described herein explores the potential of CBIQD as a new paradigm in the design and development of novel unfused or nonring-fused naphthalimide-based antimitotic cancer therapeutics in medicinal chemistry research.

14.
Nanotoxicology ; 11(6): 713-724, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28830283

RESUMO

Metal oxides (MeOx) are exponentially being used in a wide range of applications and are the largest class of commercially produced nanomaterials. This presents unprecedented human exposure. Thus, understanding nanoparticle induced cellular stress can greatly help design strategies to combat them. Scores of studies have been carried out to understand the effects of MeOx nanoparticle exposure on human alveolar cells, which are highly susceptible to aerosolized matter. There is a huge redundancy of information generated, also, a lack of a comprehensive conglomeration of this information. We have built here in a sincere summary of the cellular responses reported till date as a direct consequence of MeOx nanoparticle exposure on human alveolar (A549) cells. Detailed accounts of cellular morphology modulation, generation of reactive oxygen species (ROS) and oxidative stress, inflammation and cytokine release, genotoxic and epi-genotoxic insults, toxicological trend, nanoparticle internalization, modes of cell death, protein synthesis, and membrane damage among others are discussed. Finally, to aid predictability of the highly dynamic and multifactorial nature of this toxicity, we have hypothesized models that describe the ensuing mechanisms based on common patterns discovered throughout our literature survey.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Dano ao DNA , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Células A549 , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/patologia , Sobrevivência Celular/efeitos dos fármacos , Humanos , Modelos Biológicos , Óxidos/toxicidade , Espécies Reativas de Oxigênio/metabolismo
15.
Toxicon ; 132: 29-39, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28396155

RESUMO

Rhizostoma pulmo (Barrel Jellyfish) is one of the commonly found jellyfishes on the South-Goan coast of India. Here we present characterization of R. pulmo tentacle extract. The tentacle extracts were found to be capable of affecting the hemostatic system at three different levels, as it exhibited fibrinogenolysis, fibrinolysis and inhibition of ADP induced platelet aggregation. It preferentially cleaved the Aα chain of fibrinogen, followed by the Bß chain and the γ chain. The tentacle extract also showed significant hemolytic activity against human RBCs and strong proteolytic activity for substrates like (azo) casein and gelatin. However, this proteolytic activity was completely inhibited by EDTA (metalloproteinase inhibitor) but not by PMSF (serine proteinase inhibitor). The extract was devoid of phospholipase activity. A semi-purified protein possessing fibrinogenolytic activity was obtained by a combination of ammonium sulphate precipitation and size exclusion HPLC. Atomic absorption analysis of this protein indicated presence of Zn2+ and treatment with metalloproteinase inhibitor caused complete loss of activity. A 95 kDa metalloproteinase was identified in this fraction and was named Rhizoprotease. Protein Mass Fingerprinting of Rhizoprotease indicates it to be a novel protein.


Assuntos
Anticoagulantes/isolamento & purificação , Metaloproteases/isolamento & purificação , Cifozoários/enzimologia , Animais , Anticoagulantes/química , Eritrócitos , Fibrinogênio/metabolismo , Fibrinólise , Hemólise , Humanos , Índia , Metaloproteases/química , Agregação Plaquetária/efeitos dos fármacos , Proteólise
16.
Toxicon ; 127: 11-21, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28062165

RESUMO

'Daboialectin', a low molecular weight C-type lectin (18.5 kDa) isolated from Russell's viper venom showed cytotoxic effects on human broncho-alveolar carcinoma derived (A549) cell lines. Daboialectin induced inhibition of A549 cell growth was time and concentration dependent with severe morphological changes by altering the functions of small GTPases such as Rac, Rho and cdc42. ROS induced DNA damage may result in apoptosis by inducing disruption of membrane integrity, blebbing and nuclear disintegration by activating caspases. Our results indicate that Daboialectin, a snake c type lectin (Snaclec) isolated from RVV alters morphology of A549 cells via regulation of cytoskeleton through RHO-GTPases. On other hand, the HSP70 and some other anti-apoptotic proteins required for the survival of cancer cells was found to be down-regulated in presence of Daboialectin. Daboialectin was also found to be inhibitory to anti-adhesive and anti-invasive to A549 cells in vitro. Daboialectin is the first Snaclec reported to induce cytoskeletal changes through regulation of RHO-GTPases and blocking anti-apoptotic pathway for a cancer cell line.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Lectinas Tipo C , Venenos de Víboras/farmacologia , Células A549 , Animais , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citoesqueleto/ultraestrutura , Dano ao DNA/efeitos dos fármacos , Humanos , Proteínas Monoméricas de Ligação ao GTP/metabolismo
17.
Anim Cells Syst (Seoul) ; 21(1): 23-30, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-30460048

RESUMO

Cadmium is one of the age old toxic heavy metal, detrimental to the biological system. In this study, we explored the cellular and molecular mechanisms induced on exposure to different concentrations of cadmium chloride (CdCl2), on three different human cell lines with wild type p53, viz., A549, HEK293 and HCT116. We investigated whether the cellular responses followed, displayed any specific pattern related to their viability, mitochondrial respiration, DNA damage and apoptotic gene expression. All the cell lines showed decrease in viability following exposure to CdCl2. p53 was transcriptionally down regulated in all the three cell lines, but with different extents, in response to increasing concentration of cadmium. The cellular responses of the three cell lines were compared with that of a p53 knock out cell line (HCT116p53-/-). The p53 knock out cell line was highly sensitive to cadmium-induced toxicity; so was the cell line in which p53 mRNA expression was highly down regulated. This might implicate an unknown protective role of p53 signaling during heavy metal toxicity and that one of the possible mechanisms by which cadmium manifests its cytotoxic effect is through the transcriptional down regulation of p53 gene.

18.
Arch Biochem Biophys ; 590: 20-26, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26558696

RESUMO

A metalloproteinase anticoagulant toxin of molecular weight 66 kDa has been purified from the venom of Indian monocled cobra (Naja kaouthia). This toxin named as NKV 66 cleaved fibrinogen in a dose and time dependent manner. The digestion process was specific to Aα chain and cleaved fibrinogen to peptide fragments. NKV 66 completely liquefied the fibrin clots developed in vitro in 18 h. Plasma recalcification time and thrombin time were significantly prolonged following treatment of plasma with NKV 66. NKV 66 significantly inhibited ADP and collagen induced platelet aggregation in a dose dependent manner. It showed disintegrin like activity on A549 cells cultured in vitro. About 40% inhibition of adherence of A549 cells to matrix was observed following NKV 66 treatment also NKV 66 treated A549 cells were drastically inhibited from passing through the matrix in cell invasion assays in vitro, suggesting anti-adhesive properties of NKV 66.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Venenos Elapídicos/administração & dosagem , Metaloproteases/administração & dosagem , Agregação Plaquetária/efeitos dos fármacos , Coagulação Sanguínea/fisiologia , Adesão Celular/fisiologia , Linhagem Celular , Movimento Celular/fisiologia , Relação Dose-Resposta a Droga , Fibrinogênio/química , Fibrinolíticos , Hemólise/efeitos dos fármacos , Hemólise/fisiologia , Humanos , Cinética , Peso Molecular , Agregação Plaquetária/fisiologia
19.
Stat Methods Med Res ; 25(5): 1836-1853, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-24108268

RESUMO

In biomedical and epidemiological studies, often outcomes obtained are of mixed discrete and continuous in nature. Furthermore, due to some technical inconvenience or else, continuous responses are censored and also a few covariates cease to be observed completely. In this paper, we develop a model to tackle these complex situations. Our methodology is developed in a more general framework and provides a full-scale robust analysis of such complex models. The proposed robust maximum likelihood estimators of the model parameters are resistant to potential outliers in the data. We discuss the asymptotic properties of the robust estimators. To avoid computational difficulties involving irreducibly high-dimensional integrals, we propose a Monte Carlo method based on the Metropolis algorithm for approximating the robust maximum likelihood estimators. We study the empirical properties of these estimators in simulations. We also illustrate the proposed robust method using clustered data on blood sugar content from a clinical trial of individuals who were investigated for diabetes.


Assuntos
Algoritmos , Funções Verossimilhança , Método de Monte Carlo , Glicemia/análise , Diabetes Mellitus/sangue , Humanos , Probabilidade
20.
Toxicon ; 108: 216-25, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26519780

RESUMO

Russell's viper with its five sub-species is found throughout the Indian subcontinent. Its venom is primarily hemotoxic. However, its envenomation causes damage to several physiological systems. The present work was aimed to study the dose and time dependent cytotoxic effects of Russell's viper venom (RVV) on human A549 cells grown in vitro. Time dependent changes have been observed in cellular morphology following exposure to RVV. Presence of stress granules, rounding-off of the cells, and formation of punctate structure and loss of cell-cell contact characterized the cellular effects. Fluorescence microscopic studies revealed that apoptotic cell population increased on exposure to RVV. Further to understand the mechanism of these effects, status of small GTPase (smGTPases) expression were studied by Western blot and RT-PCR; as smGTPases play pivotal roles in deciding the cellular morphology, polarity, cell movement and overall signaling cascade. It was shown for the first time that expression patterns of Rac, Rho and CDC42 genes are altered on exposure to RVV. Similarly, significant difference in the expression pattern of HSP70 and p53 at the mRNA levels were noted. Our results confirmed that RVV induces apoptosis in A549 cells; this was further confirmed by AO/EtBr staining as well as caspase-3 assay. All experiments were compared using RVV unexposed cells. We propose for the first time that RVV induces morphological changes in human A549 cells through modulation of smGTPase expression and affects the cellular-nuclear architecture which in turn interferes in proliferation and migration of these cells along with apoptosis.


Assuntos
Expressão Gênica/efeitos dos fármacos , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Venenos de Víboras/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteína X Associada a bcl-2/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...