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

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%),

Semi-Annual Report to Congress, April 1, 2023 – September 30, 2023

First page of documen

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

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

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

Racial and Ethnic Disparities in Vaccination Coverage across Thirteen States: A County-Level Analysis

M.S.Despite significant strides in vaccine development and dissemination during the COVID-19 pandemic, limited and patchy vaccine uptake highlights a critical public health challenge for future pandemics. However, the inadequacy of detailed data has hampered our ability to understand the ethnic and racial disparities in COVID-19 vaccinations Previous research has primarily focused on national or state-level disparities, highlighting the need for county-level analyses. This study aims to bridge this gap by analyzing disparities at the county level, providing a more accurate assessment of COVID-19 vaccination inequities. Specifically, we investigate the geographic distribution of COVID-19 vaccination disparities for Black and Hispanic populations, whether there are disparities between urban and rural counties, and whether significant differences exist in racial/ethnic disparity in vaccination rates when analyzed at the county level compared to state and national rates. Data was collected from 13 state health departments between June 22, 2021, and July 22, 2021, and included COVID vaccination counts disaggregated by county and race/ethnicity group. The findings reveal significant spatial heterogeneity in both Black and Hispanic vaccination disparity. Urban areas exhibited higher levels of Black disparity. Rural areas exhibited higher levels of Hispanic disparity. It was also determined that state-level analyses significantly obscure true disparities, highlighting the importance of county-level data. The findings from this study underscore the importance of targeted interventions tailored to specific geographic contexts and emphasize the imperative forpolicymakers and public health officials to prioritize the collection and utilization of granular county-level data to effectively address racial and ethnic disparities in vaccination efforts, thereby fostering more equitable health outcomes for all communities

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

Exploring Mechanisms by Which CodY Regulate the Activity of the Sae Two-Component System to Control Virulence in Staphylococcus aureus

Ph.D.Staphylococcus aureus is a ubiquitous Gram-positive bacterium that colonizes up to 30% of the human population. As an opportunistic human pathogen, the bacterium is a leading cause of skin and soft tissue infections, endocarditis, and bacteremia. Drug resistance compounds the problem, and the lack of an efficacious vaccine emphasizes the need for new therapies to combat staphylococcal infections. One exciting approach is to target the regulation of virulence genes. Virulence genes are often regulated by multiple factors that respond to different environmental cues. Some of the factors act directly on virulence genes; others control virulence indirectly by controlling the expression or activity of other regulators. My dissertation research focuses on CodY, an amino acid- and GTP-responsive global transcriptional regulator of many metabolic pathways, and the mechanism by which it funnels nutrient depletion signals through a major regulator of virulence-the SaeR/S two-component system. Previous work by others and I in the Brinsmade lab and elsewhere showed that overexpressing the sensor kinase gene saeS and the response regulator gene saeR does not increase the expression of the Sae regulon genes. To explain this surprising result, my thesis provides experimental support for the hypothesis that CodY controls the cellular fraction of activated SaeR (SaeR~P) to adjust the expression of virulence factor genes. In Chapter II, I show that transcriptional regulation of the sae locus is dispensable for CodY-dependent upregulation of the Sae regulon. Moreover, CodY-deficient S. aureus strains have higher SaeS kinase activity, correlating with increased membrane branch- chain fatty acids derived from isoleucine. In chapter III, I show that CodY regulates SaeS kinase activity during periods of nutrient sufficiency by repressing the genes that code for enzymes and proteins that catalyze branched-chain fatty acid synthesis. Additional work herein focuses on the molecular mechanism by which the branched-chain fatty acids alter the SaeS signaling complex. My work contributes to the elucidation of a novel method of post-transcriptional virulence regulation by branched-chain fatty acids. Understanding the molecular basis of this regulation is an important first step in characterizing potentially new anti-virulence targets with therapeutic potential