School Of Basic And Applied Sciences
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Item Pseudomonas aeruginosa quorum sensing molecule N-3-oxo-dodecanoyl-Lhomoserine lactone activates human platelets through intracellular calciummediated ROS generation(Elsevier, 2018) Yadav, V. K.; Singh, P. K.; Kalia, M.; Sharma, D.; Singh, S. K.; Agarwal, V.Pseudomonas aeruginosa, an opportunistic pathogen release N-3-oxo-dodecanoyl-l-homoserine lactone (3-oxo-C12HSL) and N-butyryl-l-homoserine lactone (C4-HSL) quorum sensing (QS) molecules to regulate various virulence factors responsible for infection in the host. 3-oxo-C12 HSL not only regulates the bacterial gene expression but also modulates the host cell system. Thus, it is pertinent to evaluate the effect of these QS molecules on blood platelets which is responsible for the maintenance of hemostasis and thrombus formation. Here, in the present study, we showed that 3-oxo-C12 HSL activates platelets in a dose-dependent manner and induces intracellular calcium-mediated reactive oxygen species (ROS) release, whereas no such effect was observed with C4-HSL. 3-oxo-C12 HSL stimulated ROS release was mediated by NADPH oxidase. Results confirmed the involvement of phospholipase C (PLC) and IP3 receptor behind intracellular calcium-mediated ROS generation. The impact of 3-oxo-C12 HSL on platelet activation suggests that it could interfere and alter the normal function of platelet in individuals infected with P. aeruginosa.Item Oxidative stress stimulates invasive potential in rat C6 and human U-87 MG glioblastoma cells via activation and cross-talk between PKM2, ENPP2 and APE1 enzymes.(Springer, 2018) Cholia, Ravi P.; Dhiman, Monisha; Kumar, Raj; Mantha, Anil K.Maintaining genomic integrity is essential for cell survival and viability. Reactive oxygen species (ROS) overproduction results in oxidative stress leading to the genomic instability via generation of small base lesions in DNA and these unrepaired DNA damages lead to various cellular consequences including cancer. Recent data support the concept "oxidative stress is an indispensable participant in fostering proliferation, survival, and migration" in various cancer cell types including glioblastoma cells. In this study we demonstrate that treatment of non-cytotoxic doses of oxidants such as amyloid beta [Aβ(25-35)] peptide, glucose oxidase (GO), and hydrogen peroxide (H2O2) for 24 h and 48 h time points found to increase the expression level and activity of a multifunctional enzyme Apurinic/apyrimidinic endonuclease (APE1), a key enzyme of base excision repair (BER) pathway which takes care of base damages; and also resulted in modulation in the expression levels of downstream BER-pathway enzymes viz. PARP-1, XRCC1, DNA polβ, and ligase IIIα was observed upon oxidative stress in C6 and U-87 MG cells. Oxidants treatment to the C6 and U-87 MG cells also resulted in an elevation in the intracellular expression of glycolytic pathway enzyme Pyruvate kinase M2 (PKM2) and the metastasis inducer protein Ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) as analyzed using Western blotting and Immunofluorescence microscopic studies. Our study also reports that oxidative stress induced for 24 h and 48 h in C6 and U-87 MG cells resulted in extracellular secretion of APE1 and ENPP2 as analyzed using Western blotting in conditioned media. However, the biological significance of extracellular secreted APE1 remains elusive. Oxidative stress also elevated the ENPP2's LysoPLD activity in conditioned media of C6 and U-87 MG cells. Our results also demonstrate that oxidative stress affects the expression level and localization of APE1, PKM2, and ENPP2 in C6 and U-87 MG cells. As evidenced by the colocalization pattern at 24 h and 48 h time points, it can be attributed that oxidative stress mediates crosstalk between APE1, PKM2, and ENPP2. In addition, when C6 and U-87 MG cells were treated with lysophosphatidic acid (LPA), a bioactive lipid that negatively regulates ENPP2's LysoPLD activity at 10 μM concentration, demonstrated strong migratory potential in C6 and U-87 MG cells, and also induced migration upon oxidative stress. Altogether, the findings demonstrate the potential of C6 and U-87 MG cells to utilize three proteins viz. APE1, PKM2, and ENPP2 towards migration and survival of gliomas. Thus the knowledge on oxidative stress induced APE1's interaction with PKM2 and ENPP2 opens a new channel for the therapeutic target(s) for gliomas.Item Antioxidant potential of ganoderic acid in Notch-1 protein in neuroblastoma(Springer, 2018) Gill, Balraj Singh; Navgeet; Kuamr, SanjeevNeuroblastoma is a childhood tumor arising from developing a sympathetic nervous system and causes around 10% of pediatric tumors. Despite advancement in the use of sophisticated techniques in molecular biology, neuroblastoma patient's survivability rate is very less. Notch pathway is significant in upholding cell maintenance and developmental process of organs. Notch-1 proteins are a ligand-activated transmembrane receptor which decides the fate of the cell. Notch signaling leads to transcription of genes which indulged in numerous diseases including tumor progression. Ganoderic acid, a lanosterol triterpene, isolated from fungus Ganoderma lucidum with a wide range of medicinal values. In the present study, various isoforms of the ganoderic acid and natural inhibitors were docked by molecular docking using Maestro 9 in the Notch-1 signaling pathway. The receptor-based molecular docking exposed the best binding interaction of Notch-1 with ganoderic acid A with GScore (- 8.088), kcal/mol, Lipophilic EvdW (- 1.74), Electro (- 1.18), Glide emodel (- 89.944) with the active participation of Arg 189, Arg 199, Glu 232 residues. On the other hand natural inhibitor, curcumin has GScore (- 7.644), kcal/mol, Lipophilic EvdW (- 2.19), Electro (- 0.73), Glide emodel (- 70.957) with Arg 75 residues involved in docking. The ligand binding affinity of ganoderic acid A in Notch-1 is calculated using MM-GBSA (- 76.782), whereas curcumin has (- 72.815) kcal/mol. The QikProp analyzed the various drug-likeness parameters such as absorption, distribution, metabolism, excretion, and toxicity (ADME/T) and isoforms of ganoderic acid require some modification to fall under Lipinski rule. The ganoderic acid A and curcumin were the best-docked among different compounds and exhibits downregulation in Notch-1 mRNA expression and inhibits proliferation, viability, and ROS activity in IMR-32 cells.Item Role of Helicobacter pylori Enriched Media in Inducing Oxidative Stress in Human Cell lines(Central University of Punjab, 2018) Samal, Pallavi; Dhiman, MonishaHelicobacter pylori is a gram-negative, helical, microaerophilic bacterium which colonizes the human gastrointestinal tract. Vacuolating cytotoxin A (VacA) is one of the major virulent factors. Reactive oxygen species (ROS) and Reactive nitrogen species (RNS) produced by the immune and epithelial cells damage the host cell thereby resulting in a persistent infection. The prolonged infection results in chronic inflammation, oxidative stress and DNA damage. The microbe affects the major macromolecules of the host tissues lipids, proteins and DNA which leads to lipid peroxidation, protein oxidation and DNA fragmentation hence making the oxidative stress a deleterious damage. Role of H. pylori enriched media (HPEM) in inducing oxidative stress in two human cell lines AGS (human gastric cell line) and THP-1(human monocytic cell line) was studied in present work. The AGS cells and THP-1 cells was treated with various concentrations of HPEM and oxidative stress was evaluated by examining the levels of protein carbonyls, TBARS (thiobarbituric acid reactive species) and nitric oxide by spectophotometric and Western blotting methods. The oxidative stress induced by HPEM showed damaging effects on the cell membrane, protein and produced significantly high nitric oxide (NO) when compared with the untreated controls. From the present work it can be concluded that HPEM exposure to THP-1 and AGS cells enhanced the oxidative stress which leads to cellular damage and is ultimately responsible for the severe H. pylori associated fatal complications during its pathogenesis.Item Metformin inhibits human breast cancer cell growth by promoting apoptosis via a ROS-independent pathway involving mitochondrial dysfunction: pivotal role of superoxide dismutase (SOD)(Springer, 2018) Sharma, Prateek; Kumar, SanjeevPurpose Despite a growing body of evidence indicating a potential efficacy of the anti-diabetic metformin as anti-cancer agent, the exact mechanism underlying this efficacy has remained largely unknown. Here, we aimed at assessing putative mechanisms associated with the ability of metformin to reduce the proliferation and migration of breast cancer cells. Methods A battery of in vitro assays including MTT, colony formation, NBT and scratch wound healing assays were performed to assess the viability, proliferation, anti-oxidative potential and migration of breast cancer-derived MCF-7, MDA-MB-231 and T47D cells, respectively. Reactive oxygen species (ROS) assays along with fluorescence microscopy were used to assess apoptotic parameters. Quantification of SOD, Bcl-2, Bax, MMPs, miR-21 and miR-155 expression was performed using qRT-PCR. Results We found that metformin inhibited the growth, proliferation and clonogenic potential of the breast cancer-derived cells tested. ROS levels were found to be significantly reduced by metformin and, concomitantly, superoxide dismutase (SOD) isoforms were found to be upregulated. Mitochondrial dysfunction was observed in metformin treated cells, indicating apoptosis. In metastatic MDA-MB-231 cells, migration was found to be suppressed by metformin through deregulation of the matrix metalloproteinases MMP-2 and MMP-9. The oncogenic microRNAs miR-21 and miR-155 were found to be downregulated by metformin, which may be correlated with the suppression of cell proliferation and/or migration. Conclusions Our data indicate that metformin may play a pivotal role in modulating the anti-oxidant system, including the SOD machinery, in breast cancer-derived cells. Our observations were validated by in silico analyses, indicating a close interaction between SOD and metformin. We also found that metformin may inhibit breast cancer-derived cell proliferation through apoptosis induction via the mitochondrial pathway. Finally, we found that metformin may modulate the pro-apoptotic Bax, anti-apoptotic Bcl-2, MMP-2, MMP-9, miR-21 and miR-155 expression levels. These findings may be instrumental for the clinical management and/or (targeted) treatment of breast cancer.Item APE1: A Molecule of Focus with Neuroprotective and Anti-Cancer Properties(OMICS Publishing Group, 2013) Mantha, Anil K.Apurinic/Apyrimidinic endonuclease (APE1) is a multi-functional, central enzyme of base excision repair (BER) pathway that takes care of oxidized base damage (AP sites and strand breaks) caused by both endogenous and exogenous oxidative DNA damaging agents. In repair function, APE1 exhibits majorly abasic (AP) endonuclease activity and stable interaction(s) with BER-pathway participant proteins. Second function of APE1 is redox activation of various transcription factors (TFs e.g., c-jun, NF-kB, p53 and HIF1α) and also named as redox effector factor 1(Ref-1). In redox function, APE1 reductively activates TFs involved in regulation of gene expression for cell survival mechanisms through stable pair-wise interaction(s). Recent studies have indicated that APE1 also possesses other distinct functions such as RNA metabolism, riboendonuclease activity and protein-protein interaction for maintaining cellular homeostasis. Altered APE1 expression has been reported in various cancers and neurodegenerative diseases. Taken together such findings advocates the necessity to delineate the underlying molecular mechanism(s) for understanding its role in various biological functions, that could be translated to its application in therapeutics against human diseases like cancer, neurodegenerative diseases and other pathologies such as cardiovascular diseases.