Theses And Dissertation
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Item Assessment of antioxidant potential of phytochemicals in human glioblastoma (U-87 MG) cells(Central University of Punjab, 2014) Kaur, Manpreet; Mantha, Anil K.Imbalance between production of reactive oxygen/nitrogen species (ROS/RNS) leads to oxidative stress and has been well documented for mitochondrial dysfunction, a prime cause towards pathogenesis of neurological diseases and cancer. Glioblastoma Multiforme (GBM) is a highly aggressive, invasive and primary brain tumor which shows resistance to chemotherapy and radiotherapy. Superoxide dismutase (SOD) is an antioxidant enzyme that scavenges the production of superoxide radicals and dismutases into H?O? which is further converted into H?O and O? by catalase (CAT) enzyme. Apurinic/Apyrimidinic endonuclease (APE1) is a central enzyme of base excision repair (BER) pathway with two important functions; DNA repair and redox regulation of transcription factors (TFs) responsible for cell survival. In this study, it was seen that oxidative stress induced by endogenously found oxidants H?O? and glucose oxidase (GO) enhanced the activities of both CuZn-SOD and MnSOD in U-87 MG cells. In addition, CuZn-SOD levels were found to be increased in H?O?-induced oxidative stress and MnSOD levels were found to be increased in both H?O? and GO- induced oxidative stress. Further, pretreatment with phytochemicals Curcumin and Quercetin modulated the activities and expression of both forms of SOD studied. The BER-pathway enzyme, APE1 level was found to be decreased in mitochondria of oxidative stress induced U-87 MG cells by H?O? and GO, and in contrast APE1 level was found to be increased in cytosol, which indicates that oxidative stress affects the expression level and sub-cellular localization of APE1. Taken together, these results indicate that in GBM it is more likely that activated SOD a key player of antioxidant system and APE1 a key player in BER-pathway might be facilitating cancer cells to survive in oxidative stress environment.Item Design and synethesis of APE1 inhibitors as putative anticancer agents(Central University of Punjab, 2014) Kaur, Gagandeep; Kumar, RajSuccess in chemotherapy has not been attained completely yet and has remained a worried issue from years. Various reasons drive this failure, but the much talked about is failure due to emergence of resistance to chemotherapeutic drugs due to various factors. One of the major reasons here we have targeted is the resistance developed against DNA damaging chemotherapy due to over activation of APE1 enzyme evolved in BER pathway, which is the major repair pathway responsible for 95% of the DNA repair. Design and synthesis of APE1 inhibitors using rational approach fulfilling the pharmacophoric requirements has been carried out in this research work. Molecular modelling studies were performed to confirm that designed compounds fit well into the repair active cavity. 14 compounds have been designed and synthesized having pyrazolo-quinazolines core structure. The anticancer potential of the 8 representative compounds was evaluated against rat C-6 glial cell line at different concentrations. All synthesized compounds showed good anticancer activity against rat C-6 glial cell lines. The inhibitory potential of the compounds obtained from the MTT assay results helped us to formulate the SAR studies. Further ROS measurement was also carried out using DCFDA assay. Compounds showing good MTT results were also found to be potential antioxidants which conclude their mechanism of anticancer activity through APE1 inhibition. The active compounds may be taken further for lead optimisation and mechanistic interventions for their in vitro binding studies on APE1 in future.