Date on Master's Thesis/Doctoral Dissertation

5-2017

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Pharmacology and Toxicology

Degree Program

Pharmacology and Toxicology, PhD

Committee Chair

McMasters, Kelly

Committee Co-Chair (if applicable)

Zhou, Heshan

Committee Member

Zhou, Heshan

Committee Member

States, J. Christopher

Committee Member

Palmer, Kenneth

Committee Member

Zacharias, Wolfgang

Author's Keywords

adenovirus; JNK; oncolysis; autophagy; DNA sequencing; directed evolution

Abstract

Oncolytic adenoviruses (Ads) have great therapeutic potential for lung cancer treatment. Cancer selective E1b-deleted Ads are safe; however, their clinical cancer therapeutic efficacy remains limited. The limited efficacy of Ad virotherapy is due to many factors including inefficient cancer cell lysis, Ad release and spread. Progress in overcoming these barriers to Ad virotherapy are hampered by limited knowledge of the genes associated with enhanced Ad release and spread and the dearth of understanding of the mechanisms by which E1b-deleted Ads cause cancer cell lysis. The role of c-JNK n- terminal kinase (JNK) phosphorylation in this process remains unknown. By uncovering the molecular aspects that enhance Ad spread and oncolysis, this dissertation has addressed critical gaps in the oncolytic Ad field. In chapter II, the novel oncolytic Ad mutant, AdUV, was developed. AdUV displayed enhanced oncolytic effects, release, and spread in A549 cells. AdUV also induced autophagy more effectively than the parental strain Ad5. In chapter III, AdUV was subjected to DNA sequence analysis to determine which AdUV mutations may have induced these enhanced cancer therapeutic effects (spread, Ad release, and oncolysis). For example, mutations to the DNA-binding genes 52K and pV may have enhanced AdUV release. These mutations increased the number of encoded positively-charged amino acids in AdUV. Therefore, I hypothesized that these mutations may have increased AdUV’s binding affinity for the negatively-charged DNA sugar-phosphate backbone. In chapter IV, the mechanism of Ad-induced JNK phosphorylation was investigated to further characterize Ad oncolysis. These data indicated that Ads induce p-JNK via the expression of E1b-19K and E1a. Additionally, we have shown that the p-JNK inducer, etoposide, enhanced oncolytic effects, but not the replication of AdUV in vitro. This work has advanced the knowledge of Ad oncolysis and will lead to further progress in the field of oncolytic virotherapy.

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