Date on Master's Thesis/Doctoral Dissertation

8-2019

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Pharmacology and Toxicology

Degree Program

Pharmacology and Toxicology, PhD

Committee Chair

Siskind, Leah

Committee Co-Chair (if applicable)

Beverly, Levi

Committee Member

Beverly, Levi

Committee Member

Bates, Paula

Committee Member

Clark, Geoffrey

Committee Member

Donninger, Howard

Committee Member

Mitchell, Robert

Author's Keywords

Lung cancer; ECM; tumor microenvironment; metastasis; invasion; stem cells

Abstract

Lung cancer is the leading cause of cancer related death in the United States and worldwide. Five-year survival rates for non-small cell lung carcinoma patients have not improved in decades, and a majority of patients succumb to metastasis. Identification of therapeutic targets for metastatic disease is essential for the development of novel therapies. However, current 2-dimensional (2D) in vitro models are not reflective of the tumor microenvironment (TME) and are inadequate in identifying therapeutic targets. We adapted a 3-dimensional (3D) extracellular matrix (ECM) in vitro model to a hypoxic incubator to approximate physiological hypoxia of the TME in a microenvironment mimetic culture system. Our overall objective is to determine how ECM interactions with lung adenocarcinoma cells can promote hallmarks of cancer metastasis in a physiologically relevant in vitro system. We assessed three interactions within the TME: the interaction of cancer cells with ECM, the interaction of cancer associated stroma with ECM, and the influence of environment on ECM remodeling. Using established and primary cell lines to produce cell-derived ECM (CDM), we found that lung carcinoma cells grown on 3D CDM adopt a mesenchymal mode of 3D migration and are significantly more invasive compared to 2D. The invasive phenotype was attenuated by inhibitors downstream of “outside-in” integrin signaling including focal adhesion kinase and Src family kinases. 3D CDM and physiological hypoxia enhanced the isolation and proliferation of primary tumor stroma isolated from cancer resections of early stage patients. Patient derived cell lines maintained a stem-like phenotype and expression of tumor promoting factors in an environment dependent manner. Further, they promoted metastasis in a xenograft model and CDM produced from patient derived stroma altered invasive characteristics in cancer cells compared to normal lung fibroblast CDM. Using our microenvironment mimetic model, we demonstrate that we can study ECM-to-cell interactions in a way not possible for traditional 2D models. These interactions play a pivotal role in determining the fate of cancer cells and modulate metastatic potential. Understanding how remodeling of the TME is involved in late stage disease will allow development of preventative and curative therapeutic strategies to halt tumor progression and metastasis.

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