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Understanding And Targeting The Immunosuppressive Tumor Microenvironment, Li Cai, Li Cai

Dissertations & Theses (Open Access)

Immune checkpoint inhibitors (ICIs), such as anti-PD1/PD-L1 and anti-CTLA-4, have shown impressive antitumor efficacy by improving the activity of T cells. While these inhibitors work in many patients with various cancer types, they have minimal or no effect in many more patients. Mounting evidence indicates that, besides current known immune checkpoints, other immunosuppressive components in the tumor microenvironment (TME) need to be targeted to elicit the full immune responses.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immunosuppressive myeloid cells that are involved in cancer progression and therapeutic resistance. In this work, we demonstrated the essential role of MDSCs …

A Molecular And In Vivo Investigation Of Advanced Prostate Cancer: Deconstructing Ampk Activity And Developing An Improved Mouse Model, Sandi Wilkenfeld

Dissertations & Theses (Open Access)

Prostate cancer is one of the leading causes of cancer-related death in men. Prostate cancer is dependent on androgen receptor (AR)-mediated pathways, and AR is therefore targeted to treat advanced prostate cancer. Despite an initial response to current AR-targeted therapies, patients invariably relapse, due in large part to the reactivation of AR through a variety of mechanisms. My goal is to identify pathways downstream of AR that can be therapeutically targeted. We and others previously demonstrated that in prostate cancer, calcium/calmodulin-dependent kinase kinase 2 (CaMKK2) is a direct downstream target of AR, and can promote disease progression through the phosphorylation …

Tissue-Specific Matrix Control Of Cell Cohesion And Migration Signaling Complexes, Tristen Tellman

Dissertations & Theses (Open Access)

The extracellular matrix (ECM) is a complex, interconnected network of three major constituents: collagens, glycoproteins, and proteoglycans, along with their enzyme modifiers. Within this network and beyond the structural role, each ECM molecule contributes a context-specific signal that influences cellular fate and behavior. Among these behaviors, cellular migration provides an essential function in developing tissues, wound healing, and cancer cell metastasis. Using two glandular organs, the normal salivary gland and the cancerous prostate, this dissertation describes the tissue-specific composition of two ECM signaling complexes (type I hemidesmosomes and the perlecan-semaphorin 3A-plexin A1-neuropilin-1 (PSPN) complex) and translates this knowledge into viable …

Identification And Targeting Of Downstream Ar-Camkk2-Mediated Mechanisms For The Treatment Of Advanced Prostate Cancer, Chenchu Lin

Dissertations & Theses (Open Access)

The androgen receptor (AR) is the primary driver of prostate cancer and, therefore, AR-regulated signaling events are essential for the development and progression of the disease. Despite their initial effectiveness, drugs targeting AR eventually fail as sustained inhibition of receptor activity remains a challenge. Previously, Ca²⁺/calmodulin-dependent protein kinase kinase 2 (CAMKK2) was identified as an essential downstream component of AR signaling in prostate cancer that correspondingly tracked with disease progression. While the importance of CAMKK2 in AR-mediated prostate cancer progression has been established, our understanding of the events downstream that promote the disease remains incomplete. Here, I elucidated …

Relevance Of Fgfr1 And Its Isoforms In Prostate Cancer Bone Metastases, Estefania Labanca

Dissertations & Theses (Open Access)

The fibroblast growth factor receptor (FGFR) 1 is implicated in prostate cancer (PCa) progression. Various FGFR1 isoforms have been described and we demonstrate here that the well-characterized FGFR1 a and b isoforms are correlated with the expression of different genes and pathways in human PCa. Direct injection of PC3 PCa cells overexpressing FGFR1 isoforms into the femur of mice resulted in enhanced tumor growth and reduction in bone volume when compared with PC3 expressing empty vector. However, only PC3 overexpressing FGFR1 b was associated with increased osteoclast parameters, suggesting that each isoform may mediate diverse biological effects (similar findings were …

P53r245w Mutation Elicits Metastatic Phenotype In Pten Deficient Prostate Cancer, Ky Pham

Dissertations & Theses (Open Access)

Trp53 mutations are the most frequent genetic alterations in prostate cancer and are associated with more aggressive disease and worse overall survival. The majority of Trp53 mutations in prostate cancer are missense mutations, resulting in amino acid substitutions with profound effect. In addition to the loss of wild type function, missense mutations in Trp53 result in a gain-of-function (GOF) phenotype. This GOF phenotype confers biologic advantages to the tumor cells, enabling them to metastasize and invade distant organs. In this study, we generated mice carrying a conditional prostate-specific p53R245W mutant and Pten deletion to access the role of this common …

Integrative Bioinformatics Approaches To Elucidating Prostate Cancer Cell Heterogeneity, Plasticity, And Treatment Response, Hsueh-Ping Chao

Dissertations & Theses (Open Access)

Prostate cancer (PCa) is the most common non-cutaneous tumor in American men, and the second leading cause of cancer-related deaths. PCa-related deaths can be attributed to heterogeneous tumors containing metastatic and therapy-resistant cancer cells. Cancer stem cells (CSC) are an important contributor to this tumor heterogeneity, which are present in primary tumors and become enriched in castration resistant PCa (CRPC). Our lab has demonstrated that the prostate cancer stem cells (PCSCs) are enriched in the phenotypically undifferentiated PCa cell population that lacks the expression of differentiation marker prostate-specific antigen (PSA). Our work has also demonstrated that PCa cells manifest significant …

Outcomes Of Genetic Testing In A Genitourinary Genetics Clinic, Annelise Pace

Dissertations & Theses (Open Access)

Several known hereditary cancer syndromes confer an increased risk for genitourinary (GU)related malignancies. Various guidelines indicate when to refer patients to genetic counseling for GU-related hereditary cancer syndromes but there is limited research on the clinical picture of these patients, including their cancerous and non-cancerous features, the genetic testing strategy for this population, and the probability of having a positive germline mutation if testing is performed. The purpose of this study is to determine the most common indications for ordering genetic testing in a GU Genetics Clinic and evaluate whether there is a relationship between the indication for genetic testing …

Androgen Receptor And Prostate Cancer Cell Heterogeneity, Qu Deng

Dissertations & Theses (Open Access)

Androgen receptor (AR) plays an important role in prostate cancer (PCa) development and has been the main therapeutic target in advanced PCa. AR expression is heterogeneous in both primary PCa and castration resistant prostate cancer (CRPC). However, the functional significance of AR heterogeneity in regulating PCa biology and response to androgen/AR-targeted therapies remains unclear. The overarching hypothesis for my Ph.D is that AR heterogeneity contributes to PCa development, progression, and therapy resistance. A more specific postulate is that PCa cells expressing AR (i.e, AR⁺) and PCa cells expressing little AR (i.e, AR^-/lo) possess intrinsically distinct …

The Role Of Mir-34a In Inhibition Of Prostate Tumor Growth In The Bone And Induction Of Autophagy, Sanchaika Gaur

Dissertations & Theses (Open Access)

Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men in the United States, with most deaths occurring from bone metastasis. Several new therapies have been FDA approved for bone-metastatic PCa, but patient survival has only marginally improved due to therapy resistance, which often arises from constitutive activation of compensatory signaling pathways. This dissertation work focused on a mechanistic understanding of how cross talk between tyrosine kinase receptors contributes to therapy resistance, and how this may be overcome by downregulating expression of these receptors. In PCa cell lines and xenograft models, I demonstrated that activation of IGF-1R …

In Vivo Dosimetry Using Plastic Scintillation Detectors For External Beam Radiation Therapy, Landon S. Wootton

Dissertations & Theses (Open Access)

In vivo dosimetry, the direct measurement of dose delivered to patients during radiation therapy, has significant potential in ensuring safe and effective treatment in radiation therapy. It can serve as point-of-delivery, patient specific quality assurance and direct verification of treatment. Despite evidence that in vivo dosimetry can detect errors in patient treatment that would otherwise go undetected, it is not commonly practiced. This is due in part to a lack of available detectors ideally suited to perform in vivo dosimetry. Plastic scintillation detectors (PSDs) possess a number of dosimetric characteristics advantageous for in vivo dosimetry including water equivalence, real-time capability, …

Cancers Associated With Brca1 And Brca2 Mutations Other Than Breast And Ovarian, Jacqueline Mersch

Dissertations & Theses (Open Access)

Mutations in BRCA1 and BRCA2 cause tumor development in Hereditary Breast and Ovarian Cancer syndrome (HBOC) through accumulation of unrepaired DNA damage. Extensive research of BRCA1 and BRCA2 mutations has led to well-defined breast and ovarian cancer risks in individuals with HBOC. Previous studies have reported additional cancers associated with BRCA mutations; however, the type of cancer, magnitude of risk, and differences between sexes remains to be clarified. Ultimately, a consensus of additional cancer risks can aid in better recommendations for genetic testing and more effective screening and prevention guidelines.

A retrospective chart review of MD Anderson Cancer Center patients …

Role Of Talin1 Phosphorylation In Beta1 Integrin Activation And Prostate Cancer Metastasis, Jung-Kang Jin

Dissertations & Theses (Open Access)

Talins are adaptor proteins that regulate focal adhesion signaling by conjugating integrins to the cytoskeleton. Talins directly bind and activate integrins but the mechanism by which this occurs is unknown. As integrin activation and overexpression of talins promote prostate cancer metastasis, understanding the mechanism by which talins activate integrins will better elucidate their roles in Prostate cancer metastasis. Phosphorylation of talins on serine 425 has been associated with β1 integrin functions. Work in this dissertation tested the hypothesis that increased talin1 S425 phosphorylation was required for β1 integrin activation and promotion of prostate cancer metastasis.

I first used shRNA to …

The Role Of Il-8-Mediated Src Family Kinase Activation In Tumor-Tumor And Tumor-Stromal Interactions In Metastasis Of Prostate Cancer, Lynnelle Thorpe

Dissertations & Theses (Open Access)

Men with localized prostate cancer (PCa) have a 100% five-year survival rate, but this rate drops to 33% for men with metastatic disease. A better understanding of the metastatic process is needed to develop better therapies for PCa. Aberrant activation of protein tyrosine kinases, including Src Family Kinases (SFKs) contribute to metastasis through numerous functions, one of which leads to increased expression of cytokines, such as IL-8. However, the relationship between Src activity and IL-8 regulation is not completely understood. In cell line models, I determined that IL-8 activates Src and in turn Src activates IL-8 demonstrating a feed forward …

Microrna Regulation Of Prostate Cancer Stem/Progenitor Cells And Prostate Cancer Development, Can Liu

Dissertations & Theses (Open Access)

Most human tumors contain a population of cells with stem cell properties, called cancer stem cells (CSCs), which are believed to be responsible for tumor establishment, metastasis, and resistance to clinical therapy. It’s crucial to understand the regulatory mechanisms unique to CSCs, so that we may design CSC-specific therapeutics. Recent discoveries of microRNA (miRNA) have provided a new avenue in understanding the regulatory mechanisms of cancer. However, how miRNAs may regulate CSCs is still poorly understood. Here, we present miRNA expression profiling in six populations of prostate cancer (PCa) stem/progenitor cells that possess distinct tumorigenic properties. Six miRNAs were identified …

Clinical Trial Enrollment In A Multidisciplinary Prostate Cancer, Delora A. Domain

Dissertations & Theses (Open Access)

Purpose: Clinical oncology trials are hampered by low accrual rates. Less than 5% of adult cancer patients are treated on a clinical trial. We aimed to evaluate clinical trial enrollment in our Multidisciplinary Prostate Cancer Clinic and to assess if a clinical trial initiative, introduced in 2006, increased our trial enrollment.
Methods: Prostate cancer patients with non-metastatic disease who were seen in the clinic from 2004 to 2008 were included in the analysis. Men were categorized by whether they were seen before or after the clinical trial enrollment initiative started in 2006. The initiative included posting trial details in the …

A New Tumor Suppressor Gene Candidate Regulated By The Non-Coding Rna Pca3 In Human Prostate Cancer, Alessandro K. Lee

Dissertations & Theses (Open Access)

Prostate cancer is the second leading cause of cancer-related death and the most common non-skin cancer in men in the USA. Considerable advancements in the practice of medicine have allowed a significant improvement in the diagnosis and treatment of this disease and, in recent years, both incidence and mortality rates have been slightly declining. However, it is still estimated that 1 man in 6 will be diagnosed with prostate cancer during his lifetime, and 1 man in 35 will die of the disease.

In order to identify novel strategies and effective therapeutic approaches in the fight against prostate cancer, it …