School Of Basic And Applied Sciences

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    APE1/Ref-1 as an emerging therapeutic target for various human diseases: Phytochemical modulation of its functions
    (Nature Publishing Group, 2014) Thakur, Shweta; Sarkar, Bibekananda; Cholia, Ravi P.; Gautam, Nandini; Dhiman, Monisha; Mantha, Anil K.
    Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme involved in the base excision repair (BER) pathway, which repairs oxidative base damage caused by endogenous and exogenous agents. APE1 acts as a reductive activator of many transcription factors (TFs) and has also been named redox effector factor 1, Ref-1. For example, APE1 activates activator protein-1, nuclear factor kappa B, hypoxia-inducible factor 1a, paired box gene 8, signal transducer activator of transcription 3 and p53, which are involved in apoptosis, inflammation, angiogenesis and survival pathways. APE1/Ref-1 maintains cellular homeostasis (redox) via the activation of TFs that regulate various physiological processes and that crosstalk with redox balancing agents (for example, thioredoxin, catalase and superoxide dismutase) by controlling levels of reactive oxygen and nitrogen species. The efficiency of APE1/Ref-1's function(s) depends on pairwise interaction with participant protein(s), the functions regulated by APE1/Ref-1 include the BER pathway, TFs, energy metabolism, cytoskeletal elements and stress-dependent responses. Thus, APE1/Ref-1 acts as a 'hub-protein' that controls pathways that are important for cell survival. In this review, we will discuss APE1/Ref-1's versatile nature in various human etiologies, including neurodegeneration, cancer, cardiovascular and other diseases that have been linked with alterations in the expression, subcellular localization and activities of APE/Ref-1. APE1/Ref-1 can be targeted for therapeutic intervention using natural plant products that modulate the expression and functions of APE1/Ref-1. In addition, studies focusing on translational applications based on APE1/Ref-1-mediated therapeutic interventions are discussed. ? 2014 KSBMB.
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    An in vitro study ascertaining the role of H2O2 and glucose oxidase in modulation of antioxidant potential and cancer cell survival mechanisms in glioblastoma U-87 MG cells
    (Springer New York LLC, 2017) Cholia, Ravi P.; Kumari, Sanju; Kumar, Saurabh; Kaur, Manpreet; Kaur, Manbir; Kumar, Raj; Dhiman, Monisha; Mantha, Anil K.
    Glial cells protect themselves from the elevated reactive oxygen species (ROS) via developing unusual mechanisms to maintain the genomic stability, and reprogramming of the cellular antioxidant system to cope with the adverse effects. In the present study non-cytotoxic dose of oxidants, H2O2 (100??M) and GO (10??U/ml) was used to induce moderate oxidative stress via generating ROS in human glioblastoma cell line U-87 MG cells, which showed a marked increase in the antioxidant capacity as studied by measuring the modulation in expression levels and activities of superoxide dismutase (SOD1 and SOD2) and catalase (CAT) enzymes, and the GSH content. However, pretreatment (3?h) of Curcumin and Quercetin (10??M) followed by the treatment of oxidants enhanced the cell survival, and the levels/activities of the antioxidants studied. Oxidative stress also resulted in an increase in the nitrite levels in the culture supernatants, and further analysis by immunocytochemistry showed an increase in iNOS expression. In addition, phytochemical pretreatment decreased the nitrite level in the culture supernatants of oxidatively stressed U-87 MG cells. Elevated ROS also increased the expression of COX-2 and APE1 enzymes and pretreatment of Curcumin and Quercetin decreased COX-2 expression and increased APE1 expression in the oxidatively stressed U-87 MG cells. The immunocytochemistry also indicates for APE1 enhanced stress-dependent subcellular localization to the nuclear compartment, which advocates for enhanced DNA repair and redox functions of APE1 towards survival of U-87 MG cells. It can be concluded that intracellular oxidants activate the key enzymes involved in antioxidant mechanisms, NO-dependent survival mechanisms, and also in the DNA repair pathways for glial cell survival in oxidative-stress micro-environment. ? 2017, Springer Science+Business Media, LLC.