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- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Resource Type: Text
Description
Programmed cell death ligand-1 (PD-L1) is an overexpressed protein on many tumor cell types. PD-L1 is involved in normal immune regulation, playing an important role in self-tolerance and controlling autoimmunity. However, ligation of PD-L1 to PD-1 on activated T cells leads to tumor-mediated T cell suppression. Inhibiting the PD-1/PD-L1 pathway has emerged as an effective target for anti-tumor immunotherapies. Monoclonal antibodies (mAbs) targeting tumor-associated antigens such as PD-L1 have proven to be effective checkpoint blockades, improving therapeutic outcomes for cancer patients and receiving FDA approval as first line therapies for some cancers. A single chain variable fragment (scFv) is composed of the variable heavy and light chain regions of a mAb, connected by a flexible linker. We hypothesized that scFv proteins based on the published anti-PD-L1 monoclonal antibody sequences of atezolizumab and avelumab would bind to cell surface PD-L1. Four single chain variable fragments (scFvs) were constructed based on the sequences of these mAbs. PCR was used to assemble, construct, and amplify DNA fragments encoding the scFvs which were subsequently ligated into a eukaryotic expression vector. Mammalian cells were transfected with the scFv and scFv-IgG plasmids. The scFvs were tested for binding to PD-L1 on tumor cell lysates by western blot and to whole tumor cells by staining and flow cytometry analysis. DNA sequence analysis demonstrated that the scFv constructs were successfully amplified and cloned into the expression vectors and recombinant scFvs were produced. The binding capabilities of the scFvs constucts to PD-L1 protein were confirmed by western blot and flow cytometry analysis. This lead to the idea of constructing a CAR T cell engineered to target PD-L1, providing a possible adoptive T cell immunotherapy.
ContributorsPfeffer, Kirsten M. (Author) / Lake, Douglas (Thesis director) / Ho, Thai (Committee member) / Hastings, Karen (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Background: Coccidioidomycosis (Valley Fever) is a respiratory disease that is caused by the soil-dwelling fungi Coccidioides immitis and Coccidioides posadasii. Because fungal glycosylation patterns are distinct from mammalian glycosylation patterns, we hypothesized that certain lectins (carbohydrate-binding proteins) might have differential binding properties to coccidioidal glycoproteins, and therefore serve as a tool for the purification and characterization of these glycoproteins from patient specimens. Materials and Methods: To identify potential Coccidioides-binding lectins, lectin-based immunohistochemistry was performed using a panel of 21 lectins on lung tissue from human patients infected with Coccidioides. Enzyme-Linked Immunosorbent Assays (ELISAs) were used to confirm and test candidate Coccidioides-binding lectins for their ability to bind to proteins from antigen preparations of laboratory-grown Coccidioides. Inhibition IHC and ELISAs were used to confirm binding properties of these lectins. SDS-PAGE and mass spectrometry were performed on eluates from coccidioidal antigen preparations run through lectin-affinity chromatography columns to characterize and identify lectin-binding coccidioidal glycoproteins. Results: Two GlcNAc-binding lectins, GSLII and sWGA, bound specifically to spherules and endospores in infected human lung tissue, and not to adjacent lung tissue. The binding of these lectins to both Coccidioides proteins in lung tissue and to coccidioidal antigen preparations was confirmed to have lectin-like characteristics. SDS-PAGE analysis of eluates from lectin-affinity chromatography demonstrated that GSLII and sWGA bind to coccidioidal glycoproteins. Mass spectrometric identification of the top ten lectin affinity-purified glycoproteins demonstrated that GSLII and sWGA share affinity to a common set of coccidioidal glycoproteins. Conclusion: This is the first report of lectins that bind specifically to Coccidioides spherules and endospores in infected humans. These lectins may have the potential to serve as tools for a better method of detection and diagnosis of Valley Fever.
ContributorsChowdhury, Yasmynn (Author) / Lake, Douglas (Thesis director) / Grys, Thomas (Committee member) / Magee, Mitchell (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
Description
Valley Fever, also known as coccidioidomycosis, is a respiratory disease that affects 10,000 people annually, primarily in Arizona and California. Due to a lack of gene annotation, diagnosis and treatment of Valley Fever is severely limited. In turn, gene annotation efforts are also hampered by incomplete genome sequencing. We intend to use proteogenomic analysis to reannotate the Coccidioides posadasii str. Silveira genome from protein-level data. Protein samples extracted from both phases of Silveira were fragmented into peptides, sequenced, and compared against databases of known and predicted proteins sequences, as well as a de novo six-frame translation of the genome. 288 unique peptides were located that did not match a known Silveira annotation, and of those 169 were associated with another Coccidioides strain. Additionally, 17 peptides were found at the boundary of, or outside of, the current gene annotation comprising four distinct clusters. For one of these clusters, we were able to calculate a lower bound and an estimate for the size of the gap between two Silveira contigs using the Coccidioides immitis RS transcript associated with that cluster's peptides \u2014 these predictions were consistent with the current annotation's scaffold structure. Three peptides were associated with an actively translated transposon, and a putative active site was located within an intact LTR retrotransposon. We note that gene annotation is necessarily hindered by the quality and level of detail in prior genome sequencing efforts, and recommend that future studies involving reannotation include additional sequencing as well as gene annotation via proteogenomics or other methods.
ContributorsSherrard, Andrew (Author) / Lake, Douglas (Thesis director) / Grys, Thomas (Committee member) / Mitchell, Natalie (Committee member) / Computing and Informatics Program (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Exosomes have been known to secrete an increased amount of miRNA and noncoding genes that are abnormally expressed in various cancer subtypes. Thus, they may be an early marker for pediatric cancer types that are more difficult to diagnosis without invasive techniques, and may also help identify progression of the disease. In the project, six types of pediatric cancer cell lines, along with their extracted exosomes, were analyzed and tested for different monoclonal antibodies through western blot analysis. The genes EWS-FLI1 and FGFR4 were also identified in some cancer cell lines through Reverse-Transcriptase Polymerase Chain Reaction analysis (RT-PCR). The results were indicative of similar protein markers being found in both the originating cells and their corresponding exosomes.
ContributorsKaur Bhinder, Harsimran (Author) / Lake, Douglas (Thesis director) / Azorsa, David (Committee member) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Cancer is one of the leading causes of death in the world and represents a tremendous burden on patients, families and societies. S. Typhimurium strains are specifically attracted to compounds produced by cancer cells and could overcome the traditional therapeutic barrier. However, a major problem with using live attenuated Salmonella as anti-cancer agents is their toxicity at the dose required for therapeutic efficacy, but reducing the dose results in diminished efficacy. In this project, we explored novel means to reduce the toxicity of the recombinant attenuated Salmonella by genetically engineering those virulence factors to facilitate maximal colonization of tumor tissues and reduced fitness in normal tissues. We have constructed two sets of Salmonella strains. In the first set, each targeted gene was knocked out by deletion of the gene. In the second set, the predicted promoter region of each gene was replaced with a rhamnose-regulated promoter, which will cease the synthesis of these genes in vivo, a rhamnose-free environment.
ContributorsBenson, Lee Samuel (Author) / Kong, Wei (Thesis director) / Martin, Thomas (Committee member) / Lake, Douglas (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Center for Infectious Diseases and Vaccinology (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
The long-term survival of patients with glioblastoma multiforme is compromised by the tumor's proclivity for local invasion into the surrounding normal brain. These invasive cells escape surgery and display resistance to chemotherapeutic- and radiation-induced apoptosis. We have previously shown that tumor necrosis factor-like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor superfamily, can stimulate glioma cell invasion and survival via binding to the fibroblast growth factor-inducible 14 (Fn14) receptor and subsequent activation of the Rac1/NF-kappaB pathway. In addition, we have reported previously that Fn14 is expressed at high levels in migrating glioma cells in vitro and invading glioma cells in vivo. Here we demonstrate that TWEAK can act as a chemotactic factor for glioma cells, a potential process to drive cell invasion into the surrounding brain tissue. Specifically, we detected a chemotactic migration of glioma cells to the concentration gradient of TWEAK. Since Src family kinases (SFK) have been implicated in chemotaxis, we next determined whether TWEAK:Fn14 engagement activated these cytoplasmic tyrosine kinases. Our data shows that TWEAK stimulation of glioma cells results in a rapid phosphorylation of the SFK member Lyn as determined by multiplex Luminex assay and verified by immunoprecipitation. Immunodepletion of Lyn by siRNA oligonucleotides suppressed the chemoattractive effect of TWEAK on glioma cells. We hypothesize that TWEAK secretion by cells present in the glioma microenvironment induce invasion of glioma cells into the brain parenchyma. Understanding the function and signaling of the TWEAK-Fn14 ligand-receptor system may lead to development of novel therapies to therapeutically target invasive glioma cells.
ContributorsJameson, Nathan Meade (Author) / Anderson, Karen (Thesis director) / Lake, Douglas (Committee member) / Tran, Nhan (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Oropharyngeal cancer (OPC) is the world's sixth most common cancer and in many cases is associated with infection with human papillomavirus (HPV) type 16. Antibodies (Abs) to HPV16 viral antigens are potential diagnostic biomarkers of HPV-associated OPC (HPV OPC). A custom multiplexed bead array assay was used to detect Abs to HPV16 antigens E1, CE2, NE2, E4, E5, E6, E7, L1, and L2. Following extensive optimization of the assay, these genes were expressed as GST-fusion proteins and captured onto anti-GST magnetic beads. Serum was obtained from 256 OPC patients at the time of diagnosis and from 78 healthy controls. The median fluorescent intensity (MFI) was determined for each antigen and ratios of MFI to control GST-fusion protein were determined for each serum sample. Cutoff values were set as the mean + 3 SD of the MFIs of healthy controls and p-values were calculated using Wilcoxon unpaired and Fisher's exact test. Results of this experiment showed that HPV16 E1, CE2, NE2, E4, E6, and E7 Ab levels were elevated in OPC patients compared to controls (p<0.001), as were Ab levels to L1 (p = 0.013) and L2 (p = 0.023), per Fischer's exact test. Abs to CE2, NE2, E6, and E7 were identified as a potential biomarker panel for early detection of HPV OPC. For the 111 patients with known HPV+ tumors as measured by tumor PCR of E6 and/or E7, this assay had a sensitivity of 90% and specificity of 87% (AUC = 0.96). From these results, we conclude that custom bead array assays can be used to detect HPV16 Abs in patient sera, and we have identified a 4-Ab biomarker panel for the early detection of HPV OPC.
ContributorsGoulder, Alison Leigh (Author) / Anderson, Karen (Thesis director) / Lake, Douglas (Committee member) / Cheng, Julia (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
The treatment of melanoma is dependent on what stage the cancer has developed into. Metastatic melanoma is commonly treated with immune checkpoint inhibitors. Unfortunately, not all patients will respond to the treatment as expected. This paper develops important background knowledge on melanoma, how it is treated for each stage, and immune checkpoint inhibitors.
ContributorsStates, Savanna (Author) / Lake, Douglas (Thesis director) / Chang, Yung (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor)
Created2024-05
Description
Small cell carcinoma of the ovary (SCCOHT) is a rare ovarian cancer affecting young women and characterized by mutation in SMARCA4 and silencing of SMARCA2, two tumor suppressors that function as ATPases in the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex. SCCOHT patients face a 5-year survival rate of only 26%, but recently we have identified sensitivity of SCCOHT models to a natural product, triptolide. This study aims to ascertain the mechanism of action of triptolide. Previous SCCOHT epigenetic drug research has shown that some drugs reverse SMARCA2 epigenetic silencing to inhibit tumor growth, therefore it is hypothesized that triptolide acts the same and restores SWI/SNF function. Cells treated with triptolide have no change in SMARCA2 expression, suggesting that re-expression of epigenetically silenced tumor suppressor gene does not underlie its mechanism of action. Growth rates following triptolide treatment were observed in the presence and absence of SMARCA4, but no difference in sensitivity was observed. Thus, it is not likely that triptolide acts by restoring SWI/SNF. Others have observed that triptolide acts on xeroderma pigmentosa type B protein (XPB), a component of super-enhancers, which are DNA regions with high levels of transcription that regulate genes responsible for cell identity and oncogenes driving tumorigenesis. Both SCCOHT-1 and BIN67 cell lines treated with triptolide displayed lower expression of the super-enhancer associated MYC oncogene compared to untreated cells, supporting the theory that triptolide could be inhibiting super-enhancers regulating oncogenes.. A western blot confirmed reduced protein levels of RNA polymerase II and bromodomain 4 (BRD4), two essential components found at high levels at super-enhancers, in BIN67 cells treated with triptolide. ChIP-sequencing of Histone H3 Lysine-27 Acetylation (H3K27ac) marks in BIN67 and SCCOHT-1 cell lines identified super-enhancers in SCCOHT using tools CREAM and ROSE, which were mapped to neighboring genes associated genes and compared with the COSMIC database to identify oncogenes, of which the top 11 were examined by qRT-PCR to ascertain whether triptolide reduces their expression. It has been found that 6 out of 11 of the oncogenes examined (SALL4, MYC, SGK1, HIST1H3B, HMGA2, and CALR) decreased in expression when treated with triptolide. Thus, there is reason to believe that triptolide’s mechanism of action is via inhibition of super-enhancers that regulate oncogene expression.
ContributorsViloria, Nicolle Angela (Author) / Lake, Douglas (Thesis director) / Hendricks, William (Committee member) / Lang, Jessica (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution & Social Change (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Impairments to mitochondrial function and metabolism can make neurons vulnerable to stress and degeneration. Several studies have shown that aberrations in the electron transport chain (ETC) and the Krebs cycle are involved in the pathogenesis of Parkinson’s disease (PD). Therefore, targeting these pathways is becoming increasingly important in the discovery of new treatment for neurodegenerative diseases like PD. (−)-epigallocatechin-3-gallate (EGCG), the most common polyphenol found in Green tea, has been shown to exert neuroprotective effects and lower the risk of developing PD. However, the mechanism by which it accomplishes this remains to be elucidated. The purpose of this study was to shed light on these mechanisms by exploring the effects of EGCG against MPP+-induced mitochondrial dysfunction with PC12 cells being used as a PD pathological cell model. The cell viability differences between cells treated with varying combinations of MPP+ and EGCG were measured using a CCK-8 assay. The morphology changes induced by the different treatments were then identified with fluorescence microscopy. Next, a Seahorse assay was carried out to investigate mitochondrial function followed by GC-MS and LC-MS analysis to evaluate mitochondrial metabolism. 13C metabolic flux analysis was then used to trace the metabolic flux of the Krebs cycle. The results of the CCK-8 assay and fluorescence microscopy showed that EGCG helps attenuate the decreased viability of PC12 cells as well as the morphology changes induced by MPP+. The Seahorse and GC-MS assay found that the it also helps prevent impaired mitochondrial respiration caused by MPP+. The impaired mitochondrial respiration manifested as alterations to the Krebs cycle and glycolysis. In addition, 13C metabolic flux analysis revealed significant increases in Krebs cycle activity in MPP+-induced PC12 cells if treated with EGCG beforehand. Moreover, LC-MS showed a distinct metabolite profile for each group and identified 26 potent biomarkers. In conclusion, this study demonstrated that EGCG exerts a neuroprotective effect on PC12 cells and helps maintain mitochondrial metabolic balance in the presence of MPP+.
ContributorsLawrence, Kent Alexander (Author) / Gu, Haiwei (Thesis director) / Lake, Douglas (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05