dc.contributor.author	Szot, Christopher Sang	en
dc.contributor.committeechair	Freeman, Joseph W.	en
dc.contributor.committeechair	Rylander, M. Nichole	en
dc.contributor.committeemember	Robertson, John L.	en
dc.contributor.committeemember	Lee, Yong Woo	en
dc.contributor.committeemember	Rajagopalan, Padmavathy	en
dc.contributor.department	Biomedical Engineering	en
dc.date.accessioned	2014-07-17T12:58:25Z	en
dc.date.available	2014-07-17T12:58:25Z	en
dc.date.issued	2013-01-07	en
dc.description.abstract	The inability to accurately reproduce the complexities of the in vivo tumor microenvironment with reductionist-based two-dimensional in vitro cell culture models has been a notable deterrent in identifying therapeutic agents that reliably translate to in vivo animal and human clinical trials. In an effort to address this, a growing number of three-dimensional (3D) in vitro tumor models capable of mimicking specific tumorigenic processes have emerged within the last decade. This concept stems from the understanding that cells cultured within 3D in vitro matrices have the ability to acquire phenotypes representative of the in vivo microenvironment. The objective of this project was to apply a tissue engineering approach towards developing a 3D in vitro tumor angiogenesis model. Initially, different scaffolds were investigated for supporting 3D tumor growth, including bacterial cellulose, electrospun polycaprolactone/collagen I, and highly porous electrospun poly(L-lactic acid). However, cancer cells cultured on these scaffolds demonstrated poor adhesion, sufficient adhesion with poor infiltration, and increased but still inadequate infiltration, respectively. Collagen I hydrogels were chosen as an appropriate scaffold for facilitating 3D in vitro tumor growth for two reasons -- cell-mediated degradation and immediate 3D cell growth. It was hypothesized that cancer cells cultured within collagen I hydrogels could be encouraged to recapitulate key characteristics of in vivo tumor progression. MDA-MB-231 human breast cancer cells were shown to experience hypoxia and undergo necrosis in response to limitations in oxygen diffusion and competition for nutrients. Upregulation of hypoxia-inducible factor-1" resulted in a significant increase in vascular endothelial growth factor gene expression. To capitalize on this endogenous angiogenic potential, microvascular endothelial cells were cultured on the surface of the designated "bioengineered tumors." It was hypothesized that paracrine signaling between tumor and endothelial cells co-cultured within this system would be sufficient for inducing an angiogenic response in the absence of exogenous pro-angiogenic growth factors. Endothelial cells in the co-culture group were shown to invasively sprout into the underlying collagen matrix, forming a capillary-like tubule network. This project culminated with the establishment of an improved in vitro tumor model that can be used as a tool for accurate evaluation and refinement of cancer therapies.	en
dc.description.degree	Ph. D.	en
dc.format.medium	ETD	en
dc.identifier.other	vt_gsexam:95	en
dc.identifier.uri	http://hdl.handle.net/10919/49597	en
dc.publisher	Virginia Tech	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	tissue engineering	en
dc.subject	co-culture	en
dc.subject	collagen I hydrogel	en
dc.subject	cancer	en
dc.subject	angiogenesis	en
dc.title	A three-dimensional in vitro tumor model representative of the in vivo tumor microenvironment	en
dc.type	Dissertation	en
thesis.degree.discipline	Biomedical Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

A three-dimensional in vitro tumor model representative of the in vivo tumor microenvironment

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