Life Sciences Commons^™

Novel Regulators Of Cellular Secretion Alter The Tumor Microenvironment To Drive Metastasis, Rakhee Bajaj

Dissertations & Theses (Open Access)

Lung cancer is a highly aggressive disease responsible for ~25% of all cancer-related deaths, due in part to its proclivity to metastasize. Treating metastasis holds potential for improving patient survival but requires a deeper investigation into the underlying mechanisms. Some of these processes that can regulate metastasis are: (1) Oncogenic targets of epithelial micro-RNAs (miRNAs) are epigenetically de-repressed upon loss of the miRNAs during epithelial-to-mesenchymal transition (EMT) and in cancer. EMT confers plasticity and fitness to cancer cells promoting their survival through the metastatic cascade. This cascade and EMT are initiated by loss of the miRNA200 family (miR-200) and the …

4d Ex Vivo Crispr/Cas9 Whole-Genome Screen To Identify Genes Regulating Lung Cancer Metastasis, Alexandria Plumer

Dissertations & Theses (Open Access)

Metastatic lung cancer has a 5-year survival rate of 5%. Lung cancers tend to be asymptomatic until late stages, and almost 90% are not diagnosed until they are advanced. Metastases are very rare events, often initiated by a single cell from a primary tumor into a new niche at a distant location. Investigation of the early metastatic process is of urgent need for the development of early diagnostics and targeted therapeutics. We performed a proof-of-concept CRISPR/Cas9 whole genome knockout screen in the A549 lung adenocarcinoma cell line and utilized a novel ex vivo 4D lung metastasis model to find gene …

Uncovering The Zeb1 Interactome To Identify Novel Regulators Of Metastatic Non-Small Cell Lung Cancer, Roxsan Manshouri

Dissertations & Theses (Open Access)

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death in the United States, due in part to the robust affinity of lung cancer cells to metastasize. Understanding the processes that contribute to metastasis provides promise for the discovery of novel therapeutic targets. Epithelial-tomesenchymal transition (EMT) is a proposed model for the initiation of metastasis. During EMT cell adhesion and polarity is reduced, allowing epithelial cancer cells to dissociate from the primary tumor and invade distant organs. The transcription factor zinc finger E-box-binding homeobox 1 (ZEB1) has been reported to uniquely correlate with NSCLC disease progression and to …

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 …

Sphingosine Kinase 1 Regulates Fascin Expression To Promote Metastasis In Triple Negative Breast Cancer, Sunil Acharya

Dissertations & Theses (Open Access)

Distant metastasis is the primary cause of breast cancer–related mortality. To date, effective therapeutic drugs that target metastasis are still lacking. Triple negative breast cancer (TNBC) occurs in high frequency in young women and are more likely to recur and metastasize than are other breast cancer subtypes. Also, TNBC patients cannot benefit from currently available hormonal or targeted therapies, as they lack estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. Thus, understanding the signaling pathways that promote TNBC metastasis and developing novel therapeutic approaches to target them are critical, in order to prolong the survival and improve …

The Role Of The Epithelial-To-Mesenchymal Transition (Emt) In Lung Cancer Progression, David H. Peng

Dissertations & Theses (Open Access)

Lung cancer is the leading cause of cancer-related deaths due to conventional therapy resistance and metastatic disease, therefore understanding the mechanisms governing these biological functions is vital for improving patient survival. Approximately 30% of patients with the adenocarcinoma histologic subset of lung cancer possess an activating KRAS mutation, characterized by a lack of response to chemotherapies with a poor overall 5-year survival rate. Despite the mutational frequency, KRAS remains a challenge to pharmacologically inhibit and current drugs undergoing clinical trials that target specific downstream effector proteins of KRAS, such as MEK inhibitors, have failed to produce significant clinical benefits. Previous …

Microenvironment-Induced Pten Loss By Exosomal Microrna Primes Brain Metastasis Outgrowth, Lin Zhang

Dissertations & Theses (Open Access)

Development of life-threatening cancer metastases at distant organs requires disseminated tumor cells’ adaptation to and co-evolution with the drastically different microenvironments of metastatic sites. Cancer cells of common origin manifest distinct gene expression patterns after metastasizing to different organs. Clearly, the dynamic interplay between metastatic tumor cells and extrinsic signals at individual metastatic organ sites critically impacts the subsequent metastatic outgrowth. Yet, it is unclear when and how disseminated tumor cells acquire the essential traits from the microenvironment of metastatic organs that prime their subsequent outgrowth. Here we show that primary tumor cells with normal expression of PTEN, an important …

Investigating The Roles Of Δnp63 As A Suppressor Of Migration, Invasion, And Metastasis, Ramon E. Flores Gonzalez

Dissertations & Theses (Open Access)

Cancer is one of the leading causes of death and disease in the world. Considerable resources are spent to study and understand cancer, with the hope of developing new treatments and eventually cures that will help millions of people. Efforts to understand cancer are hindered by its inherent complexity and instability. Nonetheless, understanding the basics of tumor development and progression are the key to focused on studying the role of ΔNp63 in cancer, a p53 family member known to be involved in epithelial development, microRNA biogenesis, and stem cell maintenance. Using the strength of in vivo mouse models, we found …

Mechanisms Underlying Distinct Egfr Versus Fgfr-3 And -1 Dependency In Human Bladder Cancer Cells, Tiewei Cheng

Dissertations & Theses (Open Access)

The epidermal growth factor receptor (EGFR) and fibroblast growth factor receptor (FGFR) are activated by gene amplification, mutation and overexpression in bladder cancer, which drives tumor development and progression. Both EGFR and FGFR inhibitors are currently being tested in clinical trials. However, bladder cancer (BC) cells show remarkably heterogeneous sensitivities to both inhibitors, and the molecular determinants of this heterogeneity are presently unclear. Therefore, in this study, using selective EGFR and FGFR inhibitors in BC cells, we demonstrated that FGFR3 and FGFR1 play largely non-overlapping roles in mediating proliferation and invasion in the distinct “epithelial” and “mesenchymal” subsets of human …

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 Type I Insulin-Like Growth Factor Receptor Signaling In Breast Cancer Brain Metastasis, Sandra M. Saldana

Dissertations & Theses (Open Access)

Brain metastasis is a common cause of mortality in cancer patients. Approximately 20-30% of breast cancer patients acquire brain metastasis, yet potential therapeutic targets remain largely unknown. The type I insulin-like growth factor receptor (IGF- IR) is known to play a role in the progression of breast cancer and is currently being investigated in the clinical setting for various types of cancer. The present study demonstrates that the IGF-IR signaling axis is constitutively active in brain-seeking sublines of breast cancer cells, driving an increase in in vitro metastatic properties. We demonstrate that IGF-IR signaling is activated in an autocrine manner …

Galectin-3 Enhances The Malignant Melanoma Phenotype By Regulating Autotaxin, Russell R. Braeuer

Dissertations & Theses (Open Access)

In melanoma patient specimens and cell lines, the over expression of galectin-3 is associated with disease progression and metastatic potential. Herein, we have sought out to determine whether galectin-3 affects the malignant melanoma phenotype by regulating downstream target genes. To that end, galectin-3 was stably silenced by utilizing the lentivirus-incorporated small hairpin RNA in two metastatic melanoma cell lines, WM2664 and A375SM, and subjected to gene expression microarray analysis. We identified and validated the lysophospholipase D enzyme, autotaxin, a promoter of migration, invasion, and tumorigenesis, to be down regulated after silencing galectin-3. Silencing galectin-3 significantly reduced the promoter activity of …