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

Youth Mainstreaming in Small Arms and Light Weapons Control

This essay examines the critical issue of youth exclusion and its impact on global peace and security, focusing on the inordinate effects of armed violence on youth and the challenges hindering their integration into decision-making spheres. Despite being disproportionately affected by armed violence, youth find themselves marginalized in discussions that directly impact their lives and futures. Through an exploration of grassroots initiatives and governmental actions, the essay highlights the importance of youth mainstreaming in small arms control efforts. It proposes recommendations for research, funding, and inclusion measures to ensure meaningful youth participation in policymaking and implementation processes. Hence, the essay underscores the necessity of incorporating youth perspectives and leadership in small arms and light weapons control initiatives to foster sustainable peace and security worldwide

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

Environmental Woes and Their Economic Echoes

Ph.D.This dissertation is a compilation of three essays on the economic consequences of environmental shocks.In the first chapter, No Point Crying over Spilled Oil: Impact of Crude Oil Spills on Out-Migration in Nigeria, I study adaptation measures adopted by households in the face of land pollution shocks, namely crude oil spills. I use a staggered difference-in-differences framework to find that exposure to crude oil spills increases the likelihood of out-migration. A sub-group analysis helps me investigate the causal mechanism driving my results. I find that oil spills are linked to migration only for those who resided in households that practiced agriculture at baseline. They report fewer hours worked in cultivation and weak evidence suggests that rural household members migrate to urban areas as a consequence of oil spill exposures, indicating a substitution away from their farms. Reported short-term migration responses to oil spill exposure are often marriage-related, while longer-term migrations are reportedly driven by work and education pursuits, predominantly among female members. Thus, persistent exposure to land pollution shocks can prompt agriculture-dependent households to resort to out-migration as a coping strategy.The second chapter, High Temperature and Learning Outcomes: Evidence from Ethiopia, ---co-authored with Kibrom Tafere and A. Patrick Behrer--- investigates the impact of high temperatures on the test scores of students in high-stakes examinations in Ethiopia. We rely on quasi-random variation in daily temperature during the year preceding an exam for identification. Our results indicate that an additional day with maximum temperature exceeding 33°C leads to a significant decrease in students' total test scores by 0.009 standard deviations. We also find meaningful heterogeneity in effects based on the gender of students. Specifically, female students' exam scores appear to be less influenced by high temperatures, implying that climate change has differential impacts by gender. Additionally, we find that students from schools located in hotter regions can better cope with higher temperatures as compared to their counterparts from cooler regions. We posit this as suggestive evidence of heat acclimatization since Ethiopian schools have negligible adoption of cooling technologies.In the third chapter, Agriculture Production Potential of Groundwater Irrigation in Sub-Saharan Africa, ---co-authored with Ifeanyi N. Edochie, Aparajita Goyal, and Andrew Dabalen--- we investigate the potential of the vast under-utilized groundwater reserves available in Sub-Saharan African countries to increase agricultural production and resilience. By combining a novel groundwater aquifer database with geo-spatial agriculture productivity data, we simulate the gains from expanding groundwater access-- ensuring access is kept within sustainable limits-- on agriculture productivity and production and find substantial gains. This analysis is particularly relevant against the backdrop of climate change and the impending disruption to rain-fed agriculture

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

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

First page of documen

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

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