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Browsing Biological Sciences - Student Works by Subject "cancer treatment"
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Item 9-(2-Phosphonyl-methoxyethyl)-adenine promotes erythrocytic differentiation and disrupts cell replication in chronic myelogenous leukemia K562 cells(2021) Wiseman, Brittany; Harcombe, Kimberley; Bernstein, NinaDisruption during cellular differentiation can cause hematopoietic stem cells to proliferate uncontrollably, resulting in the development of cancer. Differentiation therapies are being investigated as a type of cancer treatment which involve inducing agents that promote the differentiation of cancer cells into those with similar properties to normal blood cells. These cells can then undergo apoptosis at an accelerated and controlled rate compared to cancer cells, making this a potential therapeutic technique. In this study, the ability of human chronic myelogenous leukemia K562 cells to undergo cellular differentiation in response to the inducing agent 9-(2-Phosphonyl-methoxy ethyl)-adenine (PMEA) is investigated. PMEA has previously been shown to disrupt cell replication, and promote erythrocytic differentiation in K562 cells. In order to further test the effectiveness of this inducer, cell proliferation was measured with a cell growth curve, hemoglobin presence was measured with benzidine staining, and gamma-globin expression (a protein subunit of fetal hemoglobin) was measured in both induced and uninduced K562 cell cultures via RT-qPCR and western blotting. The results indicate that PMEA slows cell replication, and promotes hemoglobin (and subsequently gamma-globin) expression in treated cells. In summary, the findings support the conclusion that PMEA is able to promote erythrocytic differentiation in K562 cells, and provides information that supports differentiation therapies as a method for cancer treatment.Item Biochemical characterization of DNA repair enzyme inhibitors, molecules with possible applications to improving cancer treatment(2020) Hamel, Jolie; Bernstein, NinaPolynucleotide kinase-phosphatase (PNKP) is a critical DNA repair enzyme responsible for processing DNA damage caused by radiation. A loss of function in this enzyme results in increased cell susceptibility to radiation-induced DNA damage and subsequent cell death. As radiation therapy is commonly used in cancer treatment, targeted inhibition of PNKP has been proposed to increase the effectiveness of radiation therapy at lower doses. We characterized two previously identified PNKP inhibitors, Candesartan and S4, by their effects on the kinase activity, kinase substrate binding, and phosphatase substrate binding of Caenorhabditis elegans and mouse PNKP. The binding assays were conducted using electromobility shift assays (EMSA), while in vitro kinase assays were performed to assess kinase activity. Both inhibitors had an effect on both domains of PNKP, but were more effective at displacing the phosphatase substrate than the kinase substrate. Comparisons of kinase activity inhibition by new and older samples of inhibitors showed that both Candesartan and S4 degrade over a span of 3-4 months and lose their effectiveness. These inhibitors show promise for applications in cancer treatment, but further research is needed.Item Biochemical characterization of the kinase activity of DNA repair enzyme, PNKP from C. elegans(2015) Oladogba, Oluwatosin; Bernstein, NinaDNA damage by genotoxic agents such as ionizing radiation or reactive oxygen species is likely to occur in the DNA of all living organisms. Therefore the cells of living organisms have developed complex protein networks overtime to help discover and repair DNA damage (Bernstein et al. 2005). Polynucleotide Kinase/Phosphatase (PNKP) is an enzyme that plays a crucial role in repairing a type of DNA damage known as DNA strand breaks (Bernstein et al. 2005). This enzyme has 3 domains, a kinase domain at the C-terminal, a phosphatase domain at the center, and an FHA domain at the N-terminal (Figure 1) (Bernstein et al. 2008). The kinase and phosphatase domains are responsible for directly repairing DNA strand breaks while the FHA domain is responsible for binding PNKP to other DNA repair enzymes (Bernstein et al. 2008). The general objective of this study is to analyze the kinase activity of PNKP derived from C. elegans (CePNKP) in comparison to PNKP derived from humans (hPNKP) by conducting kinase assays. A long term goal for this research is to characterize useful orthologs of PNKP for structural studies of an inhibitor binding to this enzyme. Results from this research showed that the kinase activity of CePNKP is more selective for the recessed 5’ terminus compared to the kinase activity of hPNKP, and this suggests that it might possibly be a good model for hPNKP.