Available at: https://digitalcommons.calpoly.edu/theses/2763
Date of Award
3-2024
Degree Name
MS in Biomedical Engineering
Department/Program
Biomedical Engineering
College
College of Engineering
Advisor
Chris Heylman
Advisor Department
Biomedical Engineering
Advisor College
College of Engineering
Abstract
Colorectal cancer is the second most common cause of cancer-related deaths in the United States, with the relative 5-year survival rate for distant stage cancer being only 14%. The most common treatment for colorectal cancer is with chemotherapeutic drugs; however, the discovery of these drugs is costly, time-consuming, and often requires the use of animal models that do not yield results that translate to clinical trials. Due to these shortcomings, researchers seek to develop physiologically relevant in vitro tumor models that more accurately mimic the tumor microenvironment for cheaper and faster high-throughput drug screening. The aim of this research was to develop a colorectal cancer tumor model co-cultured with endothelial and stromal cells, followed by validation with clinically relevant chemotherapeutic agents within microfluidic devices. The first experiment consisted of a lipofection of fibroblasts to yield fluorescently tagged cells that could be later imaged using a fluorescence microscope. The next experiment consisted of a co-culture of tumor, endothelial, and fibroblast cells at varying densities in a twodimensional (2D) culture to determine the optimal plating densities that would yield quantifiable tumor and endothelial network formation. The following experiment used these optimal densities to test the effects of the chemotherapeutic agents oxaliplatin and SN38 on the tumor and endothelial cells in 2D. After the various densities and drug concentrations were tested in 2D, the model was introduced into microfluidic devices. The first experiment in the devices was similar to the first experiment plated in 2D, as it involved the establishment of optimal plating densities of all three cell types within the devices. Similarly, the goal of this experiment was to yield quantifiable tumor and endothelial network formation within the devices. The final experiment performed in this research was the introduction of oxaliplatin and SN38 to the optimized densities v of cells determined from the previous experiment, with the aim of evaluating the effects of these chemotherapeutic agents on the tumor and endothelial cells within microfluidic devices. The two experiments plated in 2D established plating densities to be tested in the devices. These experiments also showed that increasing drug concentrations resulted in reduced tumor count and size and revealed no disruption in the endothelial networks when exposed to oxaliplatin concentrations as high as 50 µM. The final two experiments in microfluidic devices revealed that endothelial network formation is not yet possible within the devices with the current protocols, but that tumor cells still showed dose-dependent responses to drug exposure as they did in 2D. Due to the lack of network formation in this device model, future work is required to allow for endothelial cell organization into networks, to further increase the physiological relevancy of this model to in vivo tumor conditions.
Included in
Bioimaging and Biomedical Optics Commons, Biomedical Devices and Instrumentation Commons, Molecular, Cellular, and Tissue Engineering Commons