Addressing the Hippo in the Room: Investigating the Mechanism of YAP/TAZ as a Treatment Target in Clear Cell Renal Cell Carcinoma

Ph.D.Clear Cell Renal Cell Carcinoma (ccRCC) is the most common subtype of kidney neoplasms characterized by a near universal inactivation of the von Hippel-Lindau (VHL) tumor suppressor protein. Targeted therapies that inhibit the unfettered transcriptional signaling of Hypoxia-inducible Factor 2ɑ (HIF2ɑ) transcription factor and its downstream pro-angiogenic effectors, consequential to VHL loss, has undoubtedly improved patient survival. Despite these improvements, a substantial fraction of patients with advanced ccRCC experience upfront or acquired resistance to presently available treatment options, warranting the investigation into adjunct therapies capable of improving efficacy and response duration to existing treatments. Assessing tumor copy number alteration, methylation, and expression data from large ccRCC patient cohorts, we demonstrate that dysregulation of the Hippo tumor suppressor pathway occurs commonly in ccRCC, correlates with increased YAP/TAZ target gene expression, and is associated with worse overall survival in treatment naïve patients. In addition, we showed that high YAP/TAZ gene signature is associated with poor treatment response to therapies that target HIF2ɑ-VEGF signaling. In vivo efficacy studies with a first-in-class TEAD palmitoylation inhibitor or YAP/TAZ-targeted shRNAs showed both forms of YAP/TAZ silencing substantially delays the development of acquired resistance to a clinical HIF2ɑ inhibitor in a ccRCC xenograft model sensitive to HIF2ɑ inhibition. Moreover, the TEAD inhibitor also exhibited profound single agent anti-tumor efficacy in a patient-derived ccRCC xenograft model of upfront resistance to HIF2ɑ-targeted treatments. By combining ATAC-seq, BRB-seq and Cut&Tag analysis, we assessed the chromatin binding and gene regulation of YAP and HIF2ɑ, and unveiled that these two proteins are co-recruited to AP-1 sites through interactions with the AP-1 transcription factors. YAP/TAZ, HIF2ɑ and JUN are dependent on each other to maintain their expression, and function cooperatively to promote the expression of highly expressed transcription factors and other important oncogenes. Our findings not only revealed the therapeutic potentials of adjunct YAP/TAZ-based therapies in the treatment of advanced ccRCC, but also revealed novel mechanistic insights into the dynamic interactions among YAP, HIF2ɑ and AP-1 proteins that could be further exploited to improve treatment for ccRCC

Random Utilities and How to Find Them

Ph.D.In this dissertation, I study the random utility model. The random utility model is an extension of the classic paradigm of economics which assumes that decision makers choose according to some underlying preference. The random utility model extends this paradigm by allowing for heterogeneity across either a population of decision makers or across time for the same decision maker. This heterogeneity is modeled as there being a distribution over preferences inducing a distribution over choices. In Chapter 1, I study when an analyst is able to recover the underlying distribution over preferences from choice data. I provide fully characteristic conditions under which we are able to recover the underlying distribution over preferences. In Chapter 2, I readdress the problem of testing the random utility model. While axiomatic tests of the random utility model have been known, only recently has a hypothesis test for the random utility model been developed which can be applied to real data. However, this hypothesis test is not computationally feasible in many reasonable applications. I provide an alternative hypothesis test, applicable to real data, that offers large computational improvements over the current standard methodology. In Chapter 3, I study the random utility model in a dynamic setting where a decision maker's past choices can impact their preference today. First, I broach the problem of aggregation. In general, if a decision maker's preference depends on their history of choices, the time average of their choices does not coincide with the random utility model. I provide characteristic conditions for when the random utility model is an accurate model of time aggregated choice. Second, I develop a test for this type of dynamic random utility when we have time disaggregated but population level data. I provide a fully characteristic axiomatic test as well as a hypothesis test for history dependent random utility for this type of data

The Repeating Book: In Search of the Creole Text in the Caribbean

Ph.D.In my dissertation, I argue that Caribbean thought and literature exhibit exceptional characteristics that make them unique, sharing features that make them what I call the “creole text.” Orlando Fals Borda’s Historia Doble de la Costa (1979-86) and Antonio Benítez Rojo's La Isla que se Repite (1989) guide my analysis. Historia Doble de la Costa is a much lesser-known book, it is a tetralogy that navigates between a poetic and a historicist discourse which, for lack of a better term, can be described as a social history whose structure duplicates its pages as if it contained two books, one of them a history from below, with parallel texts on facing pages. Historia Doble de la Costa also repeats itself because each of its four volumes repeat elements of the others to narrate the histories of the different subregional islets of the Colombian Caribbean. Through drawing on Benitez Rojo idea of “repetition”, I show that this repetition characterizes textual creolity in general, such as in C.L.R. James's The Black Jacobins (1938), Fernando Ortiz's Contrapunteo Cubano del Tabaco y el Azúcar (1940), Lydia Cabrera's El Monte (1954), George Lamming's The Pleasures of the Exile (1960), Édouard Glissant's Le Discours Antillais (1981), Manuel Zapata Olivella's Changó, el Gran Putas (1983), among others. I maintain that the creole text is cannibalistic in the sense that it is a textual assemblage that combines different fields of knowledge, approaches, intellectual traditions, formats and writing styles in an undisciplined manner. This anthropophagous attitude constitutes an artistic amalgam, unclassifiable, with a tendency towards excessiveness and the baroque, generating polyphony. In this way, the creole text opens up, including not only the oral record and myth, but also narrating the agency of subjects previously considered passive objects, in particular, the historical experience of the African diaspora

Regulation of Steroid Hormone Biosynthesis by Thymic Epithelial Cells

Ph.D.Selective processes early in T cell development ensure that most thymocytes expressing αβ T cell antigen receptors (TCRs) are eliminated, and only self-restricted and self-tolerant cells join the peripheral T cell repertoire. Glucocorticoids produced by thymic epithelial cells (TECs) promote the survival of such thymocytes to increase the breadth and efficacy of the repertoire. There are two TEC subsets, cortical (cTECs) and medullary (mTECs), each contributing to selection at different developmental stages. The exact source and regulation of thymic-derived glucocorticoid production are not fully understood, and their precise identification will help determine whether they enhance positive selection or antagonize negative selection. It was hypothesized that glucocorticoids are synthesized by cTECs, with the potential to influence both stages of selection. To test this, a transgenic reporter mouse was utilized in which endogenous Cyp11b1, the final and essential enzyme in de novo glucocorticoid biosynthesis, was fused with fluorescent mScarlet. Cyp11b1mScarlet was detected in a lineage of mTECs that express the transcription factor Aire, which is known to drive promiscuous expression of tissue-restricted antigens (TRAs) involved in negative selection and the establishment of peripheral immune tolerance. In Aire-knockout mice, detection of Cyp11b1mScarlet, transcripts encoding enzymes required for the de novo pathway, and ex-vivo glucocorticoid synthesis were significantly reduced, supporting Aire’s role in regulating glucocorticoid biosynthesis. This presents a novel yet paradoxical role for Aire in promoting both positive and negative thymocyte selection, the combined effect serving to enlarge the pool of self-restricted yet self-tolerant T cells. This also supports a new function for Aire in coordinating the expression of genes involved in an entire biosynthetic pathway whose secondary products have known paracrine functions. To this end, Aire was found to drive de novo sex steroid biosynthesis, supporting a broader role for Aire in shaping the thymic microenvironment and paving the way for future investigations

Trauma-Informed Practices for Teaching and Learning

Trauma-informed pedagogy is a strategic pedagogical approach that prioritizes emotional resilience and inclusivity across academic environments. While it is a well-established paradigm in K-12 education, these pedagogical practices are not as well described in higher education. In this session, workshop participants will reflect on well-established trauma-informed principles, and through vignette based discussions, participants will collaboratively develop strategies to apply in their own educational contexts

Impact of an Open Access Scheduling System on No-Show Rates in an Urban Federally Qualified Health Center

D.N.P.No-show medical appointments lead to health disparities and threaten the financial survival of Federally Qualified Health Centers (FQHCs). Open access scheduling eliminates long lead times, a common reason for no-show visits. Preventive health screenings and chronic disease management were drastically reduced during the COVID-19 pandemic, requiring innovative methods to increase access to care. The purpose of this quality improvement (QI) project was to measure the impact of an open access scheduling system on no-show rates in an urban FQHC. A pre-post observational design compared two days per week of no-show data for a span of 10 weeks between two family medicine physicians’ schedules. No-show data from the pre-intervention group (N = 175) was collected from October 17, 2022–December 20, 2022 and compared to no-show data from the open access post-intervention group (N = 82) collected from October 16, 2023–December 19, 2023. No-show rates were significantly lower in the open access post-intervention group (3.5%) compared to the traditional pre-intervention group (36%),

Intratumor Heterogeneity Drives the Evolution of Multiple Populations with Metastatic Initiating Capabilities in a Genetically Engineered Mouse Model of Triple Negative Breast Cancer

Ph.D.Heterogeneity within primary tumors allows cancer cells to acquire traits advantageous to their survival and growth, but a better understanding of how this heterogeneity influences metastasis is required. Using a genetically engineered mouse model (GEMM) of triple negative breast cancer (TNBC), we investigated the evolution of tumor heterogeneity during disease progression, and its contribution on metastasis. Here, we show that late malignant tumors (LM) have an enhanced ability to invade and form pulmonary metastases compared to early malignant (EM) tumors. To understand the changes taking place during progression to promote this enhanced metastatic capability, we employed bulk RNA-sequencing (RNA seq) and single cell RNA-sequencing (scRNA-seq). RNA-seq revealed that LM tumors are enriched in programs that contribute to invasion and metastasis such as epithelial-mesenchymal-transition (EMT), hypoxia, and ECM-receptor interactions. Even though the contribution of EMT on metastasis is unclear, the significant upregulation of EMT genes in LM tumors led us to assess experimental lung metastases for two canonical EMT markers, EpCAM and Vimentin. We found that lung metastases formed from LM tumors expressed varying levels of Vimentin, which did not always mirror the EMT phenotype of the primary tumor. scRNA-seq revealed the transcriptional heterogeneity that exists between and within LM and EM tumors, showing subpopulations with unique molecular signatures. During tumor progression, LM tumors experience a loss of mammary epithelial lineage as observed by the downregulation in luminal genes such as Krt8, Wfdc18, Ptn, Kit, Barx2, and Prom1. However, LM tumors did not exhibit a gain in basal features (Trp63, Col17a1, and Krt14). To better understand the contribution of tumor heterogeneity on metastasis, we identified three subpopulations that were unique to LM tumors including EpCAM low, EpCAM high Itga2 low, and EpCAM high Itga2 high tumor cells. While EpCAM low subpopulations exhibited an enhanced ability to invade in vitro, EpCAM high subpopulations displayed a greater ability to form lung metastases. Importantly, we found that multiple subpopulations are comprised of metastasis-initiating cells (MICs), and this metastatic capability was independent of their EMT status. Additionally, our findings suggest that mesenchymal-epithelial-transition (MET) is not required for tumor cells to survive and proliferate after the colonization of a secondary site. Collectively, our findings reveal the existence of MICs in multiple tumor subpopulations, and provides insight to the contribution of heterogeneity and EMT on metastasis

The Relationship Between Food Insecurity and Unmet Need for Modern Contraceptives: A Country-Level Analysis

M.P.P.Though access to modern contraceptive methods (MCMs) has improved globally over the past several decades, there remains a high level of unmet need among women of reproductive age (ages 15-49), particularly in low- and lower-middle income countries (LMICs). While little past research exists that examines the impact that food insecurity has on unmet need for MCMs, what does exist suggests that food insecure women are less likely to have pregnancy intentions than women who are food secure, but simultaneously less likely to be using any form of contraception. I use country-level panel data on 122 countries between 2015 and 2022 to investigate the relationship between moderate-to-severe food insecurity (MSFI) on unmet need for MCMs among women of reproductive age. Because most past research has explored the relationship at a hyper-local level and/or taken a qualitative approach to the question, this paper represents a geographic expansion on previous work. My study findings support my hypothesis, suggesting a positive relationship between MSFI and unmet need for MCMs on a global scale that is stronger among LMICs

Under One Roof: The Relationship Between Grandparent Co-Residence and Adolescent Mental Health

M.P.P.Multigenerational living is on the rise in the United States, with more children living in multigenerational households than in previous decades. However, the bulk of the literature on multigenerational living focuses on the financial and health impacts for adult generations. The outcomes of children in multigenerational households are not well-documented, despite the fact that 10% of children under 18 resided in multigenerational households in 2023. Mental health outcomes among children and youth are of particular concern in the United States, where the prevalence of depression among adolescents has been increasing at a faster rate than any other age group since 2009. This study investigates the relationship between living in a multigenerational household and depression among children using a sample of 4,834 middle and high school survey respondents from Waves 1 and 2 of the National Longitudinal Study of Adolescent to Adult Health (Add Health). Grandparent co-residence is measured in Wave 1 (1994-95) and measures of depression incidence and symptom severity are constructed from Wave 2 (1996) responses to Center for Epidemiologic Studies Depression Scale (CES-D) instrument questions. I estimate the association between living with one or more grandparents and depression incidence and symptomatology using regression analysis in which I control for demographics, parental relationships, household structure, violence exposure and religiosity. I find no statistically significant relationship between grandparent co-residence and depression in this sample, although results indicate an inverse association between strength of parental relationships and depression incidence and symptomatology. Future research should involve a larger sample of longitudinal data in order to further shed light on the relationship between household structure and adolescent mental health

Recordando la Patria Perdida: Identidad Nacional y Memoria en Narrativas Sobre la Migración Venezolana

Ph.D.This dissertation focuses on the Venezuelan migration and refugee crisis in the twenty-first century. Through literary and film analysis and historical contextualization, I analyze how various written and audiovisual narratives represent the construction of the memory and national identity of Venezuelan migrants from dissimilar social classes and races. My work contributes to migration studies and film and literary criticism in Latin America by drawing attention to multimedia narratives that illustrate a migration crisis with global implications. The dissertation comprises four chapters. The first chapter analyzes three collective imaginary constructions that influence the memory and national identity of Venezuelan migrants. These constructions include Venezuelan nationalism based on the epic history of this country, the oil’s cultural impact in Venezuela, and the Venezuelan diaspora’s media representation as a symbol of the nation’s decline. The second chapter demonstrates how the novel La hija de la española (2021) by Karina Sainz Borgo depicts a repugnant Venezuela that contaminates the protagonist’s national identity and increases their nostalgia for a lost country. In the third chapter, I analyze how Eduardo Sánchez Rugeles’s novel Blue Label / Etiqueta Azul (2010) and Alejandro Bellame’s film Dirección Opuesta (2021) represent the protagonists’ fragmented memories and national identity within a Caracas symbolized as between rubble and ruins. The final chapter explores how the music videos “Me fui” (2019) by Reymar Perdomo and “Tonada del caminante” (2018) by Pía Páez shape the collective memory and resilience of Venezuelan migrants from the lower classes