Browsing by Author "Vaughn, Jennifer E."

Now showing 1 - 3 of 3
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    Delay Discounting as a Potential Therapeutic Target for Weight Loss in Breast Cancer Survivors
    Sukumar, Jasmine S.; Vaughn, Jennifer E.; Tegge, Allison; Sardesai, Sagar; Lustberg, Maryam; Stein, Jeffrey (MDPI, 2022-03)
    Simple Summary Obesity is a rising health epidemic in breast cancer survivors and associated with multiple negative health sequalae and increased mortality. Delay Discounting (DD) is a behavioral economic measure of an individual's valuation of future outcomes. While higher DD correlates with obesity in the general adult population, valuation of the future may impact cancer survivors differently due to their unique experiences. We assessed cross-sectional associations between DD, BMI, and healthy lifestyle behaviors in an exploratory analysis of 89 women with hormone receptor positive non-metastatic breast cancer. We found higher DD to be associated with obesity and decreased frequency of vegetable consumption. Future studies should investigate DD as a therapeutic target for novel behavioral interventions in breast cancer survivors affected by obesity. This may improve valuation of the future, increase healthy lifestyle behaviors, and facilitate weight loss to promote overall health and longevity in this population. Obesity in breast cancer (BC) survivors is associated with increased mortality. Delay discounting (DD) is a behavioral economic measure of how individuals value future outcomes. Higher DD correlates with obesity in the general population. Valuation of the future may be associated with obesity differently in cancer survivors. This study evaluated the relationship between DD and obesity in BC survivors. We report an exploratory analysis assessing cross-sectional associations between DD, BMI, and lifestyle behaviors (vegetable and fruit consumption, exercise) related to obesity in 89 women with hormone receptor positive non-metastatic BC. Multivariate linear regression analysis examined demographic and lifestyle behavior variables associated with both BMI and DD. Greater willingness to wait for larger, delayed rewards (lower DD) was significantly associated with lower BMI (standardized beta = -0.32; p < 0.01), independent of age, race, income, time since diagnosis, and menopausal status. There was no significant association between DD and fruit consumption or exercise frequency. Vegetable consumption was significantly associated with lower DD (standardized beta = 0.24; p < 0.05). Higher DD is associated with obesity and decreased frequency of vegetable consumption in BC survivors. Future studies should investigate DD as a therapeutic target for behavioral interventions to facilitate weight loss and promote longevity in this population.
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    Engineered microsystems and their application in the culture and characterization of three-dimensional (3D) breast tumor models
    Menon, Nidhi (Virginia Tech, 2021-05-26)
    Microsystems are a broad category of engineered technologies in the micro and nano scale that have a diverse range of applications. They are emerging as a powerful tool in the field of biomedical research, drug discovery, as well as clinical diagnostics and prognostics, especially with regards to cancer. One of the major challenges in precision and personalized medicine in cancer lies in the technical difficulties of ex-vivo cell culture and propagation of the limited number of primary cells derived from patients. Therefore, our aims are to 1. Develop a biologically relevant platform for culturing cancer cells and characterize how it influences the cell growth and phenotype compared to conventional 2-dimensional(2D) cell culturing techniques, 2. Isolate secondary metabolites from endophytic fungi and screen them on the platform for potential anticancer properties in a preliminary drug discovery pipeline, 3. Design and develop biosensors for quantifying cell responses in real-time within these systems. Several biomaterial scaffolds with microscale architectures have been utilized for engineering the tumor extracellular matrix, but very few studies have thoroughly characterized the phenotypic changes in their cell models, which is critical for translational applications of biomaterial systems. The overall objective of these studies is to engineer a biomimetic platform for the culture of breast cancer cells in vitro and to quantify and profile their phenotypic changes. In order to do this, we first evaluated a blank-slate matrix consisting of thiolated collagen, hyaluronic acid and heparin, cross-linked chemically via Michael addition reaction using diacrylate functionalized poly (ethylene glycol). The hydrogel network was used with triple-negative breast cancer cells and showed significant changes in characteristics, with cells self-assembling to form a 3D spheroid morphology, with higher viability, and exhibiting significantly lower cell death upon chemotherapy treatment, as well as had a decrease in proliferation. Furthemore, the transcriptomic changes quantified using RNA-Seq and Next-Gen Sequencing showed the dramatic changes in some of the commonly targeted pathways in cancer therapy. Furthermore, we were able to show the importance of our biomimetic platform in the process of drug discovery using fungal endophytes and their secondary metabolites as the source for potential anticancer molecules. Additionally, we developed gold nanoparticle and antibody-based (ICAM1 and CD11b) sensors to quantify cell responses spatiotemporally on our platform. We were able to show quenching of the green fluorescent fluorophores due to the Förster Resonance Energy Transfer mechanism between the fluorophore and the gold nanometal surface. We also observed antigen-dependent recovery of fluorescence and inhibition of energy transfer upon the antibody binding to the cell-surface receptors. Future efforts are directed towards incorporating the hydrogel system with antigen-dependent sensors in a conceptually-designed microfluidic platform to spatiotemporally quantify the expression of surface proteins in various cells of the tumor stroma. This includes the migration,infiltration, and polarization of specific immune cells. This approach will provide further insight into the heterogeneity of cells at the single-cell resolution in defined spaces within the 3D microfluidic platform.
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    Investigating Novel Targets to Inhibit Cancer Cell Survival
    Pridham, Kevin J. (Virginia Tech, 2018-04-18)
    Cancer remains the second leading cause of death in the United States and the world, despite years of research and the development of different treatments. One reason for this is cancer cells are able to survive through adaptation to their environment and aberrantly activated growth signaling. As such, developing new therapies that overcome these hurdles are necessary to combat cancer. Previous work in our laboratory using RNA interference screening identified genes that regulate the survival of glioblastoma (GBM) or autophagy in chronic myelogenous leukemia (CML) cancer cells. One screen identified Phosphatidylinositol-4,5-bisophosphate 3-kinase catalytic subunit beta (PIK3CB) in the family of Phosphatidylinositol 3-kinases (PI3K) as a survival kinase gene in GBM. Work contained in this dissertation set out to study PIK3CB mediated GBM cell survival. We report that only PIK3CB, in its family of other PI3K genes, is a biomarker for GBM recurrence and is selectively important for GBM cell survival. Another screen identified the long non-coding RNA, Linc00467, as a gene that regulates autophagy in CML. Autophagy is a dynamic survival process used by all cells, benign and cancerous, where cellular components are broken down and re-assimilated to sustain survival. Work contained in this dissertation set out to characterize the role that Linc00467 serves in regulating autophagy in a myriad of cancers. Collectively our data have showed Linc00467 to actively repress levels of autophagy in cancer cells. Further, our data revealed an important role for Linc00467 in regulating the stability of the autophagy regulating protein serine-threonine kinase 11 (STK11). Because of the unique role that Linc00467 serves in regulating autophagy we renamed it as, autophagy regulating long intergenic noncoding RNA or ARLINC. Taken together the work in this dissertation unveils the inner-workings of two important cancer cell survival pathways and shows their potential for development into therapeutic targets to treat cancer.