Investigating the Applications of Electroporation Therapy for Targeted Treatment of Glioblastoma Multiforme Based on Malignant Properties of Cells

Glioblastoma multiforme (GBM) is the most common and lethal primary brain cancer with an average survival time of 15 months. GBM is considered incurable with even the most aggressive multimodal therapies and is characterized by near universal recurrence. Irreversible electroporation (IRE) is a cellular ablation method currently being investigated as a therapy for a variety of cancers. Application of IRE involves insertion of electrodes into tissue to deliver pulsed electric fields (PEFs), which destabilize the cell membrane past the point of recovery, thereby inducing cell death. While this treatment modality has numerous advantages, the lack of selectivity for malignant cells limits its application in the brain where damage to healthy tissue is especially deleterious. In this dissertation we hypothesize that a form of IRE therapy, high-frequency IRE (H-FIRE), may be able to act as a selective targeted therapy for GBM due to its ability to create an electric field inside a cell to interact with altered inner organelles. Through a comprehensive investigation involving experimental testing combined with numerical modeling, we have attained results in strong support of this hypothesis. Using tissue engineered hydrogels as our platform for therapy testing, we demonstrate selective ablation of GBM cells. We develop mathematical models that predict the majority of the electric field produced by H-FIRE pulses reach the inside of the cell. We demonstrate that the increased nuclear to cytoplasm ratio (NCR) of malignant GBM cells compared to healthy brain—evidenced in vivo and in in vitro tissue mimics—is correlated with greater ablation volumes and thus lower electric field thresholds for cell death when treated with H-FIRE. We enhance the selectivity achieved with H-FIRE using a molecularly targeted drug that induces an increase in NCR. We tune the treatment pulse parameters to increase selective malignant cell killing. Finally, we demonstrate the ability of H-FIRE to ablate therapy-resistant GBM cells which are a focus of many next-generation GBM therapies. We believe the evidence presented in this dissertation represents the beginning stages in the development of H-FIRE as a selective therapy to be used for treatment of human brain cancer.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Biomedical Engineering

Department dc:contributor.department

Biomedical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2017

Author dc:creator

• Ivey, Jill Winters

Chair dc:contributor.committeechair

• Verbridge, Scott

Committee members dc:contributor.committeemember

• Davalos, Rafael V.
• Rossmeisl, John H. Jr.
• Lee, Yong Woo
• Sheng, Zhi

• pulsed electric fields
• tissue engineering
• hydrogels
• brain cancer therapy
• glioma
• cell morphology
• bipolar pulses
• high frequency

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:12574

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/78806